Merge branch 'hotfix/v0.5.4'

Debugging hotfix

.clang-format

@@ -11,23 +11,24 @@
 ---
 AccessModifierOffset: -4
 AlignAfterOpenBracket: Align
-AlignConsecutiveAssignments: false
+AlignConsecutiveAssignments: true
 AlignConsecutiveDeclarations: false
+AlignConsecutiveMacros: true
 #AlignEscapedNewlines: Left # Unknown to clang-format-4.0
-AlignOperands: true
-AlignTrailingComments: false
+AlignOperands: AlignAfterOperator
+AlignTrailingComments: true
 AllowAllParametersOfDeclarationOnNextLine: false
-AllowShortBlocksOnASingleLine: false
 AllowShortCaseLabelsOnASingleLine: false
 AllowShortFunctionsOnASingleLine: None
-AllowShortIfStatementsOnASingleLine: false
-AllowShortLoopsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: Never
+AllowShortLoopsOnASingleLine: true
+AllowShortBlocksOnASingleLine: Always
 AlwaysBreakAfterDefinitionReturnType: None
 AlwaysBreakAfterReturnType: None
 AlwaysBreakBeforeMultilineStrings: false
-AlwaysBreakTemplateDeclarations: false
+AlwaysBreakTemplateDeclarations: Yes
 BinPackArguments: true
-BinPackParameters: true
+BinPackParameters: false
 BraceWrapping:
   AfterClass: false
   AfterControlStatement: false
@@ -52,7 +53,7 @@ BreakConstructorInitializersBeforeComma: false
 #BreakConstructorInitializers: BeforeComma # Unknown to clang-format-4.0
 BreakAfterJavaFieldAnnotations: false
 BreakStringLiterals: false
-ColumnLimit: 80
+ColumnLimit: 0
 CommentPragmas: '^ IWYU pragma:'
 #CompactNamespaces: false # Unknown to clang-format-4.0
 ConstructorInitializerAllOnOneLineOrOnePerLine: false
@@ -463,7 +464,7 @@ SpacesInContainerLiterals: false
 SpacesInCStyleCastParentheses: false
 SpacesInParentheses: false
 SpacesInSquareBrackets: false
-Standard: Cpp03
+Standard: Auto
 TabWidth: 4
-UseTab: Always
+UseTab: Never
 ...

.github/workflows/main.yml

@@ -0,0 +1,90 @@
+name: Main
+on:
+    push:
+        branches-ignore:
+            - "releases/**"
+        paths-ignore:
+            - "**.md"
+            - ".gitignore"
+    pull_request:
+        paths-ignore:
+            - "**.md"
+            - ".gitignore"
+jobs:
+    doxygen:
+        name: Doxygen
+        runs-on: ubuntu-latest
+        steps:
+            - name: Clone repo
+              uses: actions/checkout@v3
+
+            - name: Install Doxygen Ubuntu
+              run: |
+                  sudo apt-get update
+                  sudo apt-get install -y doxygen nasm
+
+            - name: Generate documentation
+              run: |
+                  cmake -B build -D DOXYGEN_WARN_AS_ERROR=NO
+                  cmake --build build --target mentos_documentation
+
+    test:
+        name: Build
+        strategy:
+            fail-fast: false
+            matrix:
+                include: [
+                    # You can access the following values via ${{ matrix.??? }}
+                    #
+                    #   pkgs         : apt-get package names.  It can include multiple package names which are delimited by space.
+                    #   cc           : C compiler executable.
+                    #   cxx          : C++ compiler executable for `make ctocpptest`.
+                    #   x32          : Set 'true' if compiler supports x32.  Otherwise, set 'false'.
+                    #                  Set 'fail' if it supports x32 but fails for now.  'fail' cases must be removed.
+                    #   x86          : Set 'true' if compiler supports x86 (-m32).  Otherwise, set 'false'.
+                    #                  Set 'fail' if it supports x86 but fails for now.  'fail' cases must be removed.
+                    #   cxxtest      : Set 'true' if it can be compiled as C++ code.  Otherwise, set 'false'.
+                    #   freestanding : Set 'true' if it can be compiled and execute freestanding code.  Otherwise, set 'false'.
+                    #                  Usually, it requires Linux, x86_64 and gcc/g++.
+                    #   os           : GitHub Actions YAML workflow label.  See https://github.com/actions/virtual-environments#available-environments
+                    # gcc
+                    { pkgs: 'nasm',               cc: gcc,    cxx: g++,    os: ubuntu-latest, },
+                    { pkgs: 'gcc-12 g++-12 nasm', cc: gcc-12, cxx: g++-12, os: ubuntu-22.04,  },
+                    { pkgs: 'gcc-11 g++-11 nasm', cc: gcc-11, cxx: g++-11, os: ubuntu-22.04,  },
+                    { pkgs: 'gcc-10 g++-10 nasm', cc: gcc-10, cxx: g++-10, os: ubuntu-22.04,  },
+                    { pkgs: 'gcc-9 g++-9 nasm',   cc: gcc-9,  cxx: g++-9,  os: ubuntu-22.04,  },
+                    { pkgs: 'gcc-8 g++-8 nasm',   cc: gcc-8,  cxx: g++-8,  os: ubuntu-20.04,  },
+                    { pkgs: 'gcc-7 g++-7 nasm',   cc: gcc-7,  cxx: g++-7,  os: ubuntu-20.04,  },
+                    # clang
+                    { pkgs: 'nasm',          cc: clang,    cxx: clang++,    os: ubuntu-latest, },
+                    { pkgs: 'clang-14 nasm', cc: clang-14, cxx: clang++-14, os: ubuntu-22.04,  },
+                    { pkgs: 'clang-13 nasm', cc: clang-13, cxx: clang++-13, os: ubuntu-22.04,  },
+                    { pkgs: 'clang-12 nasm', cc: clang-12, cxx: clang++-12, os: ubuntu-22.04,  },
+                    { pkgs: 'clang-11 nasm', cc: clang-11, cxx: clang++-11, os: ubuntu-22.04,  },
+                    { pkgs: 'clang-10 nasm', cc: clang-10, cxx: clang++-10, os: ubuntu-20.04,  },
+                    { pkgs: 'clang-9 nasm',  cc: clang-9,  cxx: clang++-9,  os: ubuntu-20.04,  },
+                    { pkgs: 'clang-8 nasm',  cc: clang-8,  cxx: clang++-8,  os: ubuntu-20.04,  },
+                    { pkgs: 'clang-7 nasm',  cc: clang-7,  cxx: clang++-7,  os: ubuntu-20.04,  },
+                ]
+
+        runs-on: ${{ matrix.os }}
+
+        # Set environment variables
+        env:
+            # We globally set CC and CXX to improve compatibility with .travis.yml
+            CC: ${{ matrix.cc }}
+            CXX: ${{ matrix.cxx }}
+
+        steps:
+            - name: Clone repo
+              uses: actions/checkout@v3
+
+            - name: Install dependencies
+              run: |
+                  sudo apt-get update
+                  sudo apt-get install -y ${{ matrix.pkgs }}
+
+            - name: Build
+              run: |
+                  cmake -B build
+                  cmake --build build --parallel 2 --verbose

.gitignore

@@ -1,3 +1,15 @@
+# Covers Visual Studio Code
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+!.vscode/*.code-snippets
+# Local History for Visual Studio Code
+.history/
+# Built Visual Studio Code Extensions
+*.vsix
+
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
@@ -99,3 +111,12 @@ src/initscp/initfscp
 
 # OS generated files
 .DS_Store
+
+# OS filesystem files.
+files/bin/**
+
+# ISO creation files.
+iso/boot/*.bin
+
+# Visual Studio Code
+.vscode

.travis.jml

@@ -1,23 +0,0 @@
-dist      : xenial
-sudo      : required
-language  : c
-
-matrix:
-  include:
-    - compiler: gcc
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - gcc-5
-      env: COMPILER=gcc-5
-
-before_install:
-  - sudo apt-get update -qq
-  - sudo apt-get install -qq nasm
-
-script:
-  - mkdir build
-  - cd build
-  - cmake -DCMAKE_C_COMPILER=$COMPILER .. && make

CMakeLists.txt

@@ -1,77 +1,213 @@
-cmake_minimum_required(VERSION 2.8.4)
+# =============================================================================
+# Set the minimum required version of cmake.
+cmake_minimum_required(VERSION 3.1...3.22)
+# Initialize the project.
+project(mentos C ASM)
 
-# ------------------------------------------------------------------------------
-# Add the debugging option.
-set(DEBUGGING_TYPE "DEBUG_STDIO" CACHE STRING
-    "Chose the type of debugging: DEBUG_STDIO DEBUG_LOG")
-set_property(
-    CACHE DEBUGGING_TYPE PROPERTY STRINGS
-    DEBUG_STDIO
-    DEBUG_LOG)
-if ("${DEBUGGING_TYPE}" STREQUAL "DEBUG_STDIO" OR
-    "${DEBUGGING_TYPE}" STREQUAL "DEBUG_LOG")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D${DEBUGGING_TYPE}")
-    message(STATUS "Setting debugging type to ${DEBUGGING_TYPE}.")
-else ()
-    message(FATAL_ERROR "Debugging type ${DEBUGGING_TYPE} is not valid.")
-endif ()
+# =============================================================================
+# BUILD TYPE (Debug/Release)
+# =============================================================================
+
+# Set the default build type to Debug.
+if(NOT CMAKE_BUILD_TYPE)
+    message(STATUS "Setting build type to 'Debug' as none was specified.")
+    set(CMAKE_BUILD_TYPE "Debug" CACHE STRING "Choose the type of build." FORCE)
+endif()
+
+# =============================================================================
+# DOCUMENTATION
+# =============================================================================
+add_subdirectory(doc)
+
+# =============================================================================
+# OS-SPECIFIC COMPILERS
+# =============================================================================
+
+# Add operating system specific option.
+message(STATUS "Crosscompiling : ${CMAKE_CROSSCOMPILING}")
+message(STATUS "System name    : ${CMAKE_HOST_SYSTEM_NAME}")
+message(STATUS "Kernel version : ${CMAKE_SYSTEM_VERSION}")
+if((${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Darwin") OR APPLE)
+    # Set the Apple MacOSx compilers.
+    if(CMAKE_VERSION VERSION_LESS "3.6.0")
+        include(CMakeForceCompiler)
+        cmake_force_c_compiler(i386-elf-gcc Clang)
+        cmake_force_cxx_compiler(i386-elf-g++ Clang)
+    else()
+        set(CMAKE_C_COMPILER i386-elf-gcc)
+        set(CMAKE_CXX_COMPILER i386-elf-g++)
+        set(CMAKE_AR i386-elf-ar)
+    endif()
+    # Speicfy the linker.
+    set(CMAKE_LINKER i386-elf-ld)
+    # Specify the linker flags.
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -nostdlib")
+elseif((${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Windows") OR WIN32)
+  # Windows set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -sdl)
+else()
+    # Generic Unix System.
+    # Find the `lsb_release` program.
+    find_program(LSB_RELEASE_EXEC lsb_release HINTS /usr/bin/ /usr/local/bin/)
+    # Mark the program path as advanced, we do not want it to appear as an option.
+    mark_as_advanced(LSB_RELEASE_EXEC)
+    # Get the version.
+    execute_process(
+        COMMAND "${LSB_RELEASE_EXEC}" --short --release
+        OUTPUT_VARIABLE LSB_RELEASE_VERSION_SHORT
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    message(STATUS "LSB version    : ${LSB_RELEASE_VERSION_SHORT}")
+    if(${LSB_RELEASE_VERSION_SHORT} MATCHES "^18")
+        # Ubuntu 18 set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -sdl)
+    elseif(${LSB_RELEASE_VERSION_SHORT} MATCHES "^19")
+        # Ubuntu 19
+        set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -display gtk)
+    elseif(${LSB_RELEASE_VERSION_SHORT} MATCHES "^20")
+        # Ubuntu 20
+        set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -display gtk)
+    else()
+        # set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -sdl)
+    endif()
+    # Speicfy the linker.
+    set(CMAKE_LINKER ld)
+endif()
+
+# =============================================================================
+# COMPILATION
+# =============================================================================
 
-# ------------------------------------------------------------------------------
 # Add the sub-directories.
+add_subdirectory(programs)
+add_subdirectory(programs/tests)
 add_subdirectory(mentos)
-add_subdirectory(initscp)
+add_subdirectory(libc)
 
-# ------------------------------------------------------------------------------
-# Generate the initrd filesystem.
-add_custom_target(
-    initfs
-    COMMAND echo "---------------------------------------------"
-    COMMAND echo "Initializing 'initfs'..."
-    COMMAND echo "---------------------------------------------"
-    COMMAND initfscp -s ${CMAKE_SOURCE_DIR}/files -t ${CMAKE_BINARY_DIR}/initfs -m /dev
-    COMMAND echo "---------------------------------------------"
-    COMMAND echo "Done!"
-    COMMAND echo "---------------------------------------------"
-    DEPENDS initfscp
+# =============================================================================
+# FILESYSTEM
+# =============================================================================
+
+# MentOS is compatible with EXT2 fileystems. This target generates an EXT2
+# fileystem using the content of the `files` folder.
+add_custom_target(filesystem
+    BYPRODUCTS ${CMAKE_BINARY_DIR}/rootfs.img
+    COMMAND echo '============================================================================='
+    COMMAND echo 'Creating EXT2 filesystem...'
+    COMMAND echo '============================================================================='
+    COMMAND mkdir -p ${CMAKE_SOURCE_DIR}/files/proc
+    COMMAND mkdir -p ${CMAKE_SOURCE_DIR}/files/dev
+    COMMAND mke2fs -L 'rootfs' -N 0 -d ${CMAKE_SOURCE_DIR}/files -b 4096 -m 5 -r 1 -t ext2 -v -F ${CMAKE_BINARY_DIR}/rootfs.img 32M
+    COMMAND echo '============================================================================='
+    COMMAND echo 'Done!'
+    COMMAND echo '============================================================================='
+    DEPENDS all_programs all_tests
 )
 
-# ------------------------------------------------------------------------------
-# Set memory size.
-SET(MEMORY_SIZE 1096M)
+# =============================================================================
+# EMULATION SERIAL OUTPUT OPTION
+# =============================================================================
+# Set the list of valid emulator output options.
+set(EMULATOR_OUTPUT_TYPES OUTPUT_STDIO OUTPUT_LOG)
+# Add the emulator output option.
+set(EMULATOR_OUTPUT_TYPE "OUTPUT_STDIO" CACHE STRING "Chose the type of emulator output: ${EMULATOR_OUTPUT_TYPES}")
+# List of emulator output options.
+set_property(CACHE EMULATOR_OUTPUT_TYPE PROPERTY STRINGS ${EMULATOR_OUTPUT_TYPES})
+# Check which emulator output option is currently active.
+list(FIND EMULATOR_OUTPUT_TYPES ${EMULATOR_OUTPUT_TYPE} INDEX)
+if(index EQUAL -1)
+    message(FATAL_ERROR "Emulator output type ${EMULATOR_OUTPUT_TYPE} is not valid.")
+else()
+    message(STATUS "Setting emulator output type to ${EMULATOR_OUTPUT_TYPE}.")
+endif()
 
-# ------------------------------------------------------------------------------
-# Builds the code and runs qemu with the built Os.
-SET(EMULATOR qemu-system-i386)
-if (${DEBUGGING_TYPE} STREQUAL DEBUG_LOG)
-    SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -serial file:serial.log)
-elseif (${DEBUGGING_TYPE} STREQUAL DEBUG_STDIO)
-    SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -serial stdio)
-endif ()
-SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -vga std)
-SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -k it)
-SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -sdl)
-SET(EMULATOR_FLAGS ${EMULATOR_FLAGS} -m ${MEMORY_SIZE})
-SET(EMULATOR_KERNEL -kernel mentos/kernel.bin)
-SET(EMULATOR_FS -initrd initfs)
+# =============================================================================
+# EMULATOR CONFIGURATION
+# =============================================================================
 
+# Set the emulator.
+set(EMULATOR qemu-system-i386)
+# Set the debug type.
+if(${EMULATOR_OUTPUT_TYPE} STREQUAL OUTPUT_LOG)
+    set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -serial file:${CMAKE_BINARY_DIR}/serial.log)
+elseif(${EMULATOR_OUTPUT_TYPE} STREQUAL OUTPUT_STDIO)
+    set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -serial stdio)
+endif(${EMULATOR_OUTPUT_TYPE} STREQUAL OUTPUT_LOG)
+# Set the type of video.
+set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -vga std)
+# Set the amount of memory.
+set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -m 1096M)
+# Set the EXT2 drive.
+set(EMULATOR_FLAGS ${EMULATOR_FLAGS} -drive file=${CMAKE_BINARY_DIR}/rootfs.img,format=raw)
+
+# =============================================================================
+# Booting with QEMU for fun
+# =============================================================================
+
+# This first target runs the emualtor passing the kernel binary file.
 add_custom_target(
     qemu
-    COMMAND ${EMULATOR} ${EMULATOR_FLAGS} ${EMULATOR_KERNEL} ${EMULATOR_FS}
-    DEPENDS MentOs
-    DEPENDS initfs
+    COMMAND test -e ${CMAKE_BINARY_DIR}/rootfs.img || ${CMAKE_COMMAND} -E cmake_echo_color --red "No filesystem file detected, you need to run: make filesystem"
+    COMMAND ${EMULATOR} ${EMULATOR_FLAGS} -kernel ${CMAKE_BINARY_DIR}/mentos/kernel-bootloader.bin
+    DEPENDS kernel-bootloader.bin
 )
 
-# ------------------------------------------------------------------------------
-# Builds the code and runs qemu with the built Os.
-SET(EMULATOR_FLAGS_GDB ${EMULATOR_FLAGS} -s -S)
-SET(GDB_PROG cgdb)
-SET(GDB_ARGS -x ${CMAKE_SOURCE_DIR}/.gdb.debug)
+# =============================================================================
+# Booting with QEMU+GDB for debugging
+# =============================================================================
 
+# First, we need to generate a GDB file containing all the symbols of all our
+# executables.
+add_custom_target(
+    gdbinit
+    BYPRODUCTS ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND bash ${CMAKE_SOURCE_DIR}/scripts/get_text_address.sh ${CMAKE_BINARY_DIR}/mentos/kernel.bin > ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND bash ${CMAKE_SOURCE_DIR}/scripts/get_text_address.sh ${CMAKE_BINARY_DIR}/mentos/kernel-bootloader.bin >> ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND bash ${CMAKE_SOURCE_DIR}/scripts/get_text_address.sh ${CMAKE_BINARY_DIR}/programs/tests/test_* >> ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND bash ${CMAKE_SOURCE_DIR}/scripts/get_text_address.sh ${CMAKE_BINARY_DIR}/programs/prog_* >> ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND echo "break boot.c: boot_main" >> ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND echo "break kernel.c: kmain" >> ${CMAKE_BINARY_DIR}/.gdbinit
+    COMMAND echo "target remote localhost:1234" >> ${CMAKE_BINARY_DIR}/.gdbinit
+    DEPENDS kernel-bootloader.bin
+    DEPENDS all_programs
+    DEPENDS all_tests
+    DEPENDS libc
+)
+
+# This second target runs the emualtor passing the kernel binary file, and also
+# the `-s -S` options. This basically tells the emulator to run the kernel in
+# debug mode, and pause it up until a debugger connects to it.
 add_custom_target(
     qemu-gdb
-    COMMAND xterm -geometry 160x30-0-0 -e ${EMULATOR} ${EMULATOR_FLAGS_GDB} ${EMULATOR_KERNEL} ${EMULATOR_FS} &
-    COMMAND xterm -geometry 160x30-0+0 -e ${GDB_PROG} ${GDB_ARGS} &
-    DEPENDS MentOs
-    DEPENDS initfs
+    COMMAND test -e ${CMAKE_BINARY_DIR}/rootfs.img || ${CMAKE_COMMAND} -E cmake_echo_color --red "No filesystem file detected, you need to run: make filesystem"
+    COMMAND echo "\n\n"
+    COMMAND echo "Now, QEMU has loaded the kernel, and it is waiting that you\n"
+    COMMAND echo "remotely connect to it. To start debugging, open a new shell\n"
+    COMMAND echo "in THIS same folder, and just type :\n"
+    COMMAND printf "    cgdb -q -iex %q" "add-auto-load-safe-path ."
+    COMMAND echo "\n\n"
+    COMMAND ${EMULATOR} ${EMULATOR_FLAGS} -s -S -kernel ${CMAKE_BINARY_DIR}/mentos/kernel-bootloader.bin
+    DEPENDS kernel-bootloader.bin
+    DEPENDS .gdbinit
 )
 
+# =============================================================================
+# Booting with QEMU+GRUB
+# =============================================================================
+
+# First, we need to build the ISO for the cdrom.
+add_custom_target(
+  cdrom.iso
+  COMMAND cp -rf ${CMAKE_SOURCE_DIR}/iso .
+  COMMAND cp ${CMAKE_BINARY_DIR}/mentos/kernel-bootloader.bin ${CMAKE_BINARY_DIR}/iso/boot
+  COMMAND grub-mkrescue -o ${CMAKE_BINARY_DIR}/cdrom.iso ${CMAKE_BINARY_DIR}/iso
+  DEPENDS kernel-bootloader.bin
+)
+
+# This third target runs the emualtor, but this time, the kernel binary file is
+# inside the cdrom, so we will not pass the `-kernel` option. We will pass the
+# `-cdrom` option and the `-boot d` option, all the other options will remain
+# the same.
+add_custom_target(
+    qemu-grub
+    COMMAND ${EMULATOR} ${EMULATOR_FLAGS} -boot d -cdrom ${CMAKE_BINARY_DIR}/cdrom.iso
+    DEPENDS cdrom.iso
+)

CODING_STYLE.md

@@ -1,9 +0,0 @@
-Code Styles for this project
-============================
-
-
-If you'd like to contribute you are welcome, thus refer to the following coding
-styles please:
-
-* **C**: _the Linux kernel coding style_
-  https://www.kernel.org/doc/html/v4.10/process/coding-style.html

LICENSE.md

@@ -1,7 +1,6 @@
 MIT License
 
-Copyright (c) 2019 Alessandro Danese, Enrico Fraccaroli, Luigi Capogrosso, 
-Mirco De Marchi
+Copyright (c) 2014-2022 MentOs-Team.
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,86 +1,246 @@
-MentOS
-======
+# MentOS
 
 [![forthebadge](https://forthebadge.com/images/badges/built-with-love.svg)](https://forthebadge.com)
 [![forthebadge](https://forthebadge.com/images/badges/made-with-c.svg)](https://forthebadge.com)
 [![forthebadge](https://forthebadge.com/images/badges/for-you.svg)](https://forthebadge.com)
 
-What is MentOS
------------------
+## 1. What is MentOS
 
-MentOS (Mentoring Operating system) is an open source educational operating
-system.
-The goal of MentOS is to provide a project environment that is realistic
-enough to show how a real Operating System work, yet simple enough that
-students can understand and modify it in significant ways.
+MentOS (Mentoring Operating System) is an open source educational operating
+system. The goal of MentOS is to provide a project environment that is realistic
+enough to show how a real Operating System work, yet simple enough that students
+can understand and modify it in significant ways.
 
-There are so many operating systems, why did we write MentOS?
-It is true, there are a lot of education operating system, BUT
-how many of them follow the guideline defined by Linux?
+There are so many operating systems, why did we write MentOS? It is true, there
+are a lot of education operating system, BUT how many of them follow the
+guideline de fined by Linux?
+
+MentOS aims to have the same Linux's data structures and algorithms. It has a
+well-documented source code, and you can compile it on your laptop in a few
+seconds!
 
-MentOS aims to have the same Linux's data structures and algorithms. It
-has a well-documented source code, and you can compile it on your laptop
-in a few seconds!
 If you are a beginner in Operating-System developing, perhaps MentOS is the
 right operating system to start with.
 
+Parts of MentOS are inherited or inspired by a similar educational operating 
+system called [DreamOs](https://github.com/dreamos82/DreamOs) written by Ivan
+Gualandri.
 
-Developers
-----------------
-Main Developers:
+## 2. Implemented features
+Follows the list of implemented features:
 
- * [Enrico Fraccaroli](https://github.com/Galfurian)
- * [Alessandro Danese](https://github.com/alessandroDanese88)
- * [Luigi Capogrosso](https://github.com/luigicapogrosso)
- * [Mirco De Marchi](https://github.com/mircodemarchi)
+**Processes and Events**
+ - [x] Memory protection (User vs Kernel);
+ - [x] Processes;
+ - [x] Scheduler (synchronous and asynchronous);
+ - [x] Interrupts and Exceptions;
+ - [x] Signals;
+ - [x] Timers and RTC;
+ - [x] Wait-queues;
+ - [x] System Calls;
+ - [ ] Multi-core;
+ 
+**Memory**
+ - [x] Paging;
+ - [x] Buddy System;
+ - [x] Slab Allocation;
+ - [x] Zone Allocator;
+ - [x] Cache Allocator;
+ - [x] Heap;
+ - [x] Virtual Addressing;
 
-Prerequisites
------------------
-For compiling the main system:
+**Filesystem**
+ - [x] Virtual Filesystem (VFS);
+ - [x] Initramfs;
+ - [x] EXT2;
+ - [x] Procfs;
 
- * nasm
- * gcc
- * g++
- * make
- * cmake
- * git
+**Input/Output**
+ - [x] Programmable Interrupt Controller (PIC) drivers;
+ - [x] Keyboard drivers (IT/ENG layouts);
+ - [x] Video drivers;
+ - [ ] VGA drivers;
 
-To run and try:
+I will try to keep it updated...
 
- * qemu-system-x86
+## 3. Prerequisites
 
-For debugging:
+MentOS is compatible with the main **unix-based** operating systems. It has been
+tested with *Ubuntu*, *WSL1*, *WSL2*, and  *MacOS*.
 
- * ccmake
- * gdb or cgdb
- * xterm
+### 3.1. Generic Prerequisites
 
-Compiling MentOS
------------------
-Compile and boot MentOS with qemu:
+#### 3.1.1. Compile
 
+For compiling the system:
+
+ - nasm
+ - gcc
+ - make
+ - cmake
+ - git
+ - ccmake (suggested)
+ - e2fsprogs (should be already installed)
+
+Under **MacOS**, for compiling, you have additional dependencies:
+
+ - i386-elf-binutils
+ - i386-elf-gcc
+
+#### 3.1.2. Execute
+
+To execute the operating system, you need to install:
+
+ - qemu-system-i386 (or qemu-system-x86)
+
+#### 3.1.3. Debug
+
+For debugging we suggest using:
+
+ - gdb or cgdb
+
+### 3.2. installation Prerequisites
+
+Under **Ubuntu**, you can type the following commands:
+
+```bash
+sudo apt-get update && sudo apt-get upgrade -y
+sudo apt-get install -y build-essential git cmake qemu-system-x86 nasm e2fsprogs
+sudo apt-get install -y gdb cgdb
 ```
+Note: Older versions might have `qemu-system-i386` instead of `qemu-system-x86`.
+
+Under **MacOS** you also need to install the i386-elf cross-compiler. The
+simplest installation method is through Homebrew package manager.
+Install [Homebrew](https://brew.sh/index_it) if you don't already have it, and
+then type the following commands:
+
+```bash
+brew update && brew upgrade
+brew install i386-elf-binutils i386-elf-gcc git cmake qemu nasm e2fsprogs
+brew install gdb cgdb #<- for debug only
+```
+
+## 4. Compiling MentOS and generating the EXT2 filesystem
+
+Compile MentOS with:
+
+```bash
 cd <clone_directory>
 mkdir build
 cd build
 cmake ..
 make
+```
+
+Then, generate the EXT2 filesystem with:
+
+```bash
+make filesystem
+```
+you just need to generate the filesystem once. If you change a `program` you need to re-generate the entire filesystem with `make filesystem`, but this will override any changes you made to the files inside the `rootfs.img`. In the future I will find a way to update just the `/usr/bin` directory and the programs.
+
+## 5. Running MentOS
+
+Boot MentOS with qemu:
+
+```bash
 make qemu
 ```
 
-If you want to access to the shell, use one of the usernames listed in files/passwd.
+To login, use one of the usernames listed in `files/etc/passwd`.
 
-Change the scheduling algorithm
------------------
+## 6. Kernel logging
+The kernel provides ways of printing logging messages *from* inside the kernel code *to* the bash where you executed the `make qemu`.
 
-MentOS provides three different scheduling algorithms:
-
-* Round-Robin
-* Priority
-* Completely Fair Scheduling
-
-If you want to change the scheduling algorithm:
+These *logging* functions are:
+```C++
+#define pr_emerg(...)
+#define pr_alert(...)
+#define pr_crit(...)
+#define pr_err(...)
+#define pr_warning(...)
+#define pr_notice(...)
+#define pr_info(...)
+#define pr_debug(...)
+#define pr_default(...)
 ```
+
+You use them like you would use a `printf`:
+```C++
+    if (fd < 0) {
+        pr_err("Failed to open file '%s', received file descriptor %d.\n", filename, fd);
+        return 1;
+    }
+```
+
+By default only message that goes from `pr_notice` included down to `pr_emerg` are displayed.
+
+Each logging function (they are actually macros) is a wrapper that automatically sets the desired **log level**. Each log level is identified by a number, and declared as follows:
+```C++
+#define LOGLEVEL_DEFAULT (-1) ///< default-level messages.
+#define LOGLEVEL_EMERG   0    ///< system is unusable.
+#define LOGLEVEL_ALERT   1    ///< action must be taken immediately.
+#define LOGLEVEL_CRIT    2    ///< critical conditions.
+#define LOGLEVEL_ERR     3    ///< error conditions.
+#define LOGLEVEL_WARNING 4    ///< warning conditions.
+#define LOGLEVEL_NOTICE  5    ///< normal but significant condition.
+#define LOGLEVEL_INFO    6    ///< informational.
+#define LOGLEVEL_DEBUG   7    ///< debug-level messages.
+```
+
+You can change the logging level by including the following lines at the beginning of your source code:
+```C++
+// Include the kernel log levels.
+#include "sys/kernel_levels.h"
+/// Change the header.
+#define __DEBUG_HEADER__ "[ATA   ]"
+/// Set the log level.
+#define __DEBUG_LEVEL__ LOGLEVEL_INFO
+```
+This example sets the `__DEBUG_LEVEL__`, so that all the messages from `INFO` and below are shown. While `__DEBUG_HEADER__` is just a string that is automatically prepended to your message, helping you identifying from which code the message is coming from.
+
+## 7. Change the scheduling algorithm
+
+MentOS supports scheduling algorithms for aperiodic:
+
+ - Round-Robin (RR)
+ - Highest Priority
+ - Completely Fair Scheduling (CFS)
+ - Aperiodic Earliest Deadline First (AEDF)
+
+It also supports periodic algorithms:
+
+ - Earliest Deadline First (EDF)
+ - Rate Monotonic (RM)
+
+If you want to change the scheduling algorithm, to Round-Robin (RR) for instance:
+
+```bash
+cd build
+cmake -DSCHEDULER_TYPE=SCHEDULER_RR ..
+make
+make qemu
+```
+
+or you can activate one of the others:
+
+```bash
+# Highest Priority
+cmake -DSCHEDULER_TYPE=SCHEDULER_PRIORITY ..
+# Completely Fair Scheduling (CFS)
+cmake -DSCHEDULER_TYPE=SCHEDULER_CFS      ..
+# Earliest Deadline First (EDF)
+cmake -DSCHEDULER_TYPE=SCHEDULER_EDF      ..
+# Rate Monotonic (RM)
+cmake -DSCHEDULER_TYPE=SCHEDULER_RM       ..
+# Aperiodic Earliest Deadline First (AEDF)
+cmake -DSCHEDULER_TYPE=SCHEDULER_AEDF     ..
+```
+
+Otherwise you can use `ccmake`:
+
+```bash
 cd build
 cmake ..
 ccmake ..
@@ -97,72 +257,85 @@ ENABLE_BUDDY_SYSTEM              OFF
 SCHEDULER_TYPE                   SCHEDULER_RR
 ```
 
-Select SCHEDULER_TYPE, and type Enter to scroll the three available algorithms
-(SCHEDULER_RR, SCHEDULER_PRIORITY, SCHEDULER_CFS).
-Afterwards,
-```
-type c
-type g
+Select SCHEDULER_TYPE, and type Enter to scroll the three available algorithms (SCHEDULER_RR, SCHEDULER_PRIORITY, SCHEDULER_CFS, SCHEDULER_EDF, SCHEDULER_RM, SCHEDULER_AEDF). Afterwards, you need to
+
+```bash
+<press c>
+<press g>
 make
 make qemu
 ```
 
-Enable to Buddy System
------------------
+## 8. Use Debugger
 
-MentOS provides a Buddy System to manage the allocation and deallocation of
-page frames in the physical memory.
+If you want to use GDB to debug MentOS, first you need to compile everything:
 
-If you want to enable the MentOS's Buddy System:
-```
-cd build
-cmake ..
-ccmake ..
-```
-
-Now you should see something like this:
-
-```
-BUILD_DOCUMENTATION              ON
-CMAKE_BUILD_TYPE
-CMAKE_INSTALL_PREFIX             /usr/local
-DEBUGGING_TYPE                   DEBUG_STDIO
-ENABLE_BUDDY_SYSTEM              OFF
-SCHEDULER_TYPE                   SCHEDULER_RR
-```
-
-Select ENABLE_BUDDY_SYSTEM, and type Enter.
-You should see something like this:
-```
-BUILD_DOCUMENTATION              ON
-CMAKE_BUILD_TYPE
-CMAKE_INSTALL_PREFIX             /usr/local
-DEBUGGING_TYPE                   DEBUG_STDIO
-ENABLE_BUDDY_SYSTEM              ON
-SCHEDULER_TYPE                   SCHEDULER_RR
-```
-
-Afterwards,
-```
-type c
-type g
-make
-make qemu
-```
-
-Use Debugger
------------------
-If you want to use GDB to debug MentOS:
-```
+```bash
 cd build
 cmake ..
 make
+```
+
+Then, you need to generate a file called `.gdbinit` placed inside the `build` directory, which will tell **gdb** which *object* file he needs to read in order to allow proper debugging. Basically, it provides for each binary file, the location of their `.text` section. To generate the file, just execute:
+```bash
+make gdbinit
+```
+
+Finally, you run qemu in debugging mode with:
+```bash
 make qemu-gdb
 ```
 
-If you did everything correctly, you should have 3 windows with:
+If you did everything correctly, you should see an empty QEMU window. Basically, QEMU is waiting for you to connect *remotely* with gdb. Anyway, running `make qemu-gdb` will make your current shell busy, you cannot call `gdb` in it. You need to open a new shell inside the `build` folder and do a:
+```bash
+cgdb -q -iex 'add-auto-load-safe-path .'
 ```
-1) - Kernel Booting on qemu
-2) - Shell with video printing of statistics previously discussed
-3) - Debugger cgdb with code screening
+
+Now you should have in front of you:
+ 1. the QEMU window waiting for you;
+ 2. the **first** shell where you ran `make qemu-gdb`, which is also waiting for you;
+ 3. the **second** shell where `gdb` is runnign and, you guessed it, is waiting for you.
+
+By default I placed a breakpoint at the begginning of (1) the *bootloader* and (2) the *kernel* itself.
+
+So, when gdb starts you need to first give a continue:
+```bash
+(gdb) continue
 ```
+
+This will make the kernel run, and stop at the **first** breakpoint which is inside the *bootloader*:
+```bash
+Breakpoint 1, boot_main (...) at .../mentos/src/boot.c:220
+220     {
+```
+
+giving a second `continue` will get you to the start of the operating system:
+
+This will make the kernel run, and stop at the **second** breakpoint which is inside the *kernel*:
+```bash
+Breakpoint 2, kmain (...) at .../mentos/src/kernel.c:95
+95      {
+```
+
+## 9. Contributors
+
+Project Manager:
+
+* [Enrico Fraccaroli](https://github.com/Galfurian)
+
+Developers:
+* [Alessandro Danese](https://github.com/alessandroDanese88), [Luigi Capogrosso](https://github.com/luigicapogrosso), [Mirco De Marchi](https://github.com/mircodemarchi)
+    - Protection ring
+    - libc
+* Andrea Cracco
+    - Buddy System, Heap, Paging, Slab, Caching, Zone
+    - Process Image, ELF
+    - VFS: procfs
+    - Bootloader
+* Linda Sacchetto, Marco Berti
+    - Real time scheduler
+* Daniele Nicoletti, Filippo Ziche
+    - Real time scheduler (Asynchronous EDF)
+    - Soft IRQs
+    - Timer
+    - Signals

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-

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@@ -1 +0,0 @@
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doc/CMakeLists.txt

@@ -0,0 +1,290 @@
+# Find Doxygen
+find_package(Doxygen)
+
+if (DOXYGEN_FOUND)
+    # Read the file with the version.
+    file(READ ${PROJECT_SOURCE_DIR}/mentos/inc/version.h version_file)
+    # Extract the OS version.
+    string(REGEX MATCH "OS_MAJOR_VERSION ([0-9]*)" _ ${version_file})
+    set(OS_MAJOR_VERSION ${CMAKE_MATCH_1})
+    string(REGEX MATCH "OS_MINOR_VERSION ([0-9]*)" _ ${version_file})
+    set(OS_MINOR_VERSION ${CMAKE_MATCH_1})
+    string(REGEX MATCH "OS_MICRO_VERSION ([0-9]*)" _ ${version_file})
+    set(OS_MICRO_VERSION ${CMAKE_MATCH_1})
+    # Setup the Doxygen documentation.
+    set(DOXYGEN_PROJECT_NAME "MentOS")
+    set(DOXYGEN_PROJECT_NUMBER "${OS_MAJOR_VERSION}.${OS_MINOR_VERSION}.${OS_MICRO_VERSION}")
+    set(DOXYGEN_PROJECT_BRIEF "The Mentoring Operating System")
+    set(DOXYGEN_USE_MDFILE_AS_MAINPAGE ${PROJECT_SOURCE_DIR}/README.md)
+    set(DOXYGEN_IMAGE_PATH ${PROJECT_SOURCE_DIR}/doc/resources)
+    set(DOXYGEN_SHOW_INCLUDE_FILES NO)
+    set(DOXYGEN_GENERATE_TREEVIEW NO)
+    set(DOXYGEN_WARN_NO_PARAMDOC YES)
+    set(DOXYGEN_HTML_STYLESHEET ${PROJECT_SOURCE_DIR}/doc/doxygen.css)
+    doxygen_add_docs(
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+        ${PROJECT_SOURCE_DIR}/README.md
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+        ${PROJECT_SOURCE_DIR}/LICENSE.md
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+        ${PROJECT_SOURCE_DIR}/mentos/inc/klib/stack_helper.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/klib/stdatomic.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/link_access.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/buddysystem.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/gfp.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/kheap.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/paging.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/slab.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/vmem_map.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/mem/zone_allocator.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/multiboot.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/process/prio.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/process/process.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/process/scheduler.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/process/wait.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/proc_access.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/errno.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/ipc.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/kernel_levels.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/module.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/reboot.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/types.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/sys/utsname.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/system/panic.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/system/printk.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/system/signal.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/system/syscall.h
+        ${PROJECT_SOURCE_DIR}/mentos/inc/version.h
+        ${PROJECT_SOURCE_DIR}/mentos/src/boot.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/descriptor_tables/exception.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/descriptor_tables/gdt.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/descriptor_tables/idt.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/descriptor_tables/interrupt.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/descriptor_tables/tss.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/devices/fpu.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/devices/pci.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/ata.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/fdc.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/keyboard/keyboard.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/keyboard/keymap.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/mouse.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/ps2.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/drivers/rtc.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/elf/elf.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/ext2.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/ioctl.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/namei.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/open.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/procfs.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/readdir.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/read_write.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/stat.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/fs/vfs.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/hardware/cpuid.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/hardware/pic8259.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/hardware/timer.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/debug.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/mm_io.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/port_io.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/proc_running.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/proc_system.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/proc_video.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/stdio.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/vga/vga.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/io/video.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/ipc/msg.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/ipc/sem.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/ipc/shm.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/kernel/sys.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/kernel.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/assert.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/ctype.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/fcvt.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/hashmap.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/libgen.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/list.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/math.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/mutex.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/ndtree.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/rbtree.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/spinlock.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/strerror.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/string.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/time.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/vscanf.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/klib/vsprintf.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/buddysystem.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/kheap.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/paging.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/slab.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/vmem_map.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/mem/zone_allocator.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/multiboot.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/process/process.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/process/scheduler.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/process/scheduler_algorithm.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/process/wait.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/sys/module.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/sys/utsname.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/system/errno.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/system/panic.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/system/printk.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/system/signal.c
+        ${PROJECT_SOURCE_DIR}/mentos/src/system/syscall.c
+    )
+endif (DOXYGEN_FOUND)

doc/HOWTO_use_grub_script.md

@@ -1,17 +0,0 @@
-* * *
-### Come usare lo script per generare un'entry di GRUB #
-* * *
-
-#### 1. Inserire la partizione dei sorgenti
-Questo significa dire al programma in quale partizione si trova la vostra directory dei sorgenti.
-Ad esempio se siete su **/dev/hda2**, dovrete inserire **hda2**
-
-#### 2. Inserire il mountpoint
-Tale partizione ha un mountpoint (se non lo conoscete, date da shell il comando mount senza argomenti oppure date uno sguardo in **/etc/fstab**). Ad esempio potrà essere **/** o anche **/home/vostroutente** se tenete la home directory in una partizione separata.
-
-#### 3. Attenzione al path
-Il path dell'immagine di MentOS sarà calcolato automaticamente, ma per fare questo lo script dev'essere nella stessa directory dell'immagine.
-Dopodiché vi basta confermare ed avere la vostra entry nel file **menu.lst**
-
-**ATTENZIONE: Usatelo solo se sapete cosa state facendo. Lo script e' stato testato e funziona, ma non rispondiamo di eventuali blocchi del vostro computer.**
-

doc/scan_codes_it.md

@@ -0,0 +1,105 @@
+
+#define KEY_LEFT_WIN      0xE05b
+#define KEY_RIGHT_WIN     0xE05c
+
+                        Normal  Shifted Ctrl    Alt
+KEY_A               0x001E  A           0x1E61  0x1E41  0x1E01  0x1E00  
+KEY_B               0x0030  B           0x3062  0x3042  0x3002  0x3000  
+KEY_C               0x002E  C           0x2E63  0x2E42  0x2E03  0x2E00  
+KEY_D               0x0020  D           0x2064  0x2044  0x2004  0x2000  
+KEY_E               0x0012  E           0x1265  0x1245  0x1205  0x1200  
+KEY_F               0x0021  F           0x2166  0x2146  0x2106  0x2100  
+KEY_G               0x0022  G           0x2267  0x2247  0x2207  0x2200  
+KEY_H               0x0023  H           0x2368  0x2348  0x2308  0x2300  
+KEY_I               0x0017  I           0x1769  0x1749  0x1709  0x1700  
+KEY_J               0x0024  J           0x246A  0x244A  0x240A  0x2400  
+KEY_K               0x0025  K           0x256B  0x254B  0x250B  0x2500  
+KEY_L               0x0026  L           0x266C  0x264C  0x260C  0x2600  
+KEY_M               0x0032  M           0x326D  0x324D  0x320D  0x3200  
+KEY_N               0x0031  N           0x316E  0x314E  0x310E  0x3100  
+KEY_O               0x0018  O           0x186F  0x184F  0x180F  0x1800  
+KEY_P               0x0019  P           0x1970  0x1950  0x1910  0x1900  
+KEY_Q               0x0010  Q           0x1071  0x1051  0x1011  0x1000  
+KEY_R               0x0013  R           0x1372  0x1352  0x1312  0x1300  
+KEY_S               0x001F  S           0x1F73  0x1F53  0x1F13  0x1F00  
+KEY_T               0x0014  T           0x1474  0x1454  0x1414  0x1400  
+KEY_U               0x0016  U           0x1675  0x1655  0x1615  0x1600  
+KEY_V               0x002F  V           0x2F76  0x2F56  0x2F16  0x2F00  
+KEY_W               0x0011  W           0x1177  0x1157  0x1117  0x1100  
+KEY_X               0x002D  X           0x2D78  0x2D58  0x2D18  0x2D00  
+KEY_Y               0x0015  Y           0x1579  0x1559  0x1519  0x1500  
+KEY_Z               0x002C  Z           0x2C7A  0x2C5A  0x2C1A  0x2C00
+
+KEY_1               0x0002  1 !         0x0231  0x0221  0x0000  0x7800
+KEY_2               0x0003  2 "         0x0332  0x0322  0x0300  0x7900
+KEY_3               0x0004  3 £         0x0433  0x049C  0x0000  0x7A00
+KEY_4               0x0005  4 $         0x0534  0x0524  0x0000  0x7B00
+KEY_5               0x0006  5 %         0x0635  0x0625  0x0000  0x7C00
+KEY_6               0x0007  6 &         0x0736  0x075E  0x071E  0x7D00
+KEY_7               0x0008  7 /         0x0837  0x0826  0x0000  0x7E00
+KEY_8               0x0009  8 (         0x0938  0x0928  0x0000  0x7F00
+KEY_9               0x000A  9 )         0x0A39  0x0A29  0x0000  0x8000
+KEY_0               0x000B  0 =         0x0B30  0x0B3D  0x0000  0x8100
+
+KEY_GRAVE           0x0029  \ |         0x295C  0x297C  0x0000  0x2900
+KEY_APOSTROPHE      0x000C  ' ?         0x0C27  0x0C3F  0x0000  0x8200
+KEY_I_ACC           0x000D  ì ^         0x0D8D  0x0D5E  0x0000  0x8300
+KEY_LEFT_BRAKET     0x001A  è é [       0x1A8A  0x1A82  0x0000  0x1A5B
+KEY_RIGHT_BRAKET    0x001B  + * ]       0x1B2B  0x1B2A  0x0000  0x1B5D
+KEY_SEMICOLON       0x0027  ò ç @       0x2795  0x2780  0x0000  0x2740
+KEY_DOUBLE_QUOTES   0x0028  à ° #       0x2885  0x28A7  0x0000  0x2823
+KEY_BACKSLASH       0x002B  ù §         0x2B97  0x2BA7  0x0000  0x2B00
+KEY_KP_LESS         0x0056  < >         0x563C  0x563E  0x0000  0x5600
+KEY_COMMA           0x0033  , ;         0x332C  0x333B  0x0000  0x3300
+KEY_PERIOD          0x0034  . :         0x342E  0x343A  0x0000  0x3400
+KEY_MINUS           0x0035  - _         0x352D  0x355F  0x0000  0x3500
+
+KEY_F1              0x003B  F1          0x3B00  0x5400  0x5E00  0x6800
+KEY_F2              0x003C  F2          0x3C00  0x5500  0x5F00  0x6900
+KEY_F3              0x003D  F3          0x3D00  0x5600  0x6000  0x6A00
+KEY_F4              0x003E  F4          0x3E00  0x5700  0x6100  0x6B00
+KEY_F5              0x003F  F5          0x3F00  0x5800  0x6200  0x6C00
+KEY_F6              0x0040  F6          0x4000  0x5900  0x6300  0x6D00
+KEY_F7              0x0041  F7          0x4100  0x5A00  0x6400  0x6E00
+KEY_F8              0x0042  F8          0x4200  0x5B00  0x6500  0x6F00
+KEY_F9              0x0043  F9          0x4300  0x5C00  0x6600  0x7000
+KEY_F10             0x0044  F10         0x4400  0x5D00  0x6700  0x7100
+KEY_F11             0x0057  F11         0x5700  0x5900  0x5B00  0x5D00
+KEY_F12             0x0058  F12         0x5800  0x5A00  0x5C00  0x5E00
+
+KEY_BACKSPACE       0x000E  BackSpace   0x0E08  0x0E08  0x0E7F  0x0E00
+KEY_ENTER           0x001C  Enter       0x1C0D  0x1C0D  0x1C0A  0xA600
+KEY_ESCAPE          0x0001  Esc         0x011B  0x011B  0x011B  0x0100
+KEY_TAB             0x000F  Tab         0x0F09  0x0F00  0x9400  0xA500
+KEY_SPACE           0x0039  SpaceBar    0x3920  0x3920  0x3920  0x3920
+
+KEY_INSERT          0xE052  Ins         0x5200  0x5230  0x9200  0xA200
+KEY_HOME            0xE047  Home        0x4700  0x4737  0x7700  0x9700
+KEY_PAGE_UP         0xE049  PgUp        0x4900  0x4939  0x8400  0x9900
+KEY_DELETE          0xE053  Del         0x5300  0x532E  0x9300  0xA300
+KEY_END             0xE04F  End         0x4F00  0x4F31  0x7500  0x9F00
+KEY_PAGE_DOWN       0xE051  PgDn        0x5100  0x5133  0x7600  0xA100
+
+KEY_UP_ARROW        0xE048  Up Arrow    0x4800  0x4838  0x8D00  0x9800
+KEY_DOWN_ARROW      0xE050  Down Arrow  0x5000  0x5032  0x9100  0xA000
+KEY_LEFT_ARROW      0xE04B  Left Arrow  0x4B00  0x4B34  0x7300  0x9B00
+KEY_RIGHT_ARROW     0xE04D  Right Arrow 0x4D00  0x4D36  0x7400  0x9D00
+
+KEY_KP_DIV          0xE035  Kp.Div      0xE035  0xE035  0x3500  0x3500
+KEY_KP_MUL          0x0037  Kp.Mul      0x372A  0x372A  0x3700  0x3700
+KEY_KP_SUB          0x004A  Kp.Sub      0x4A2D  0x4A2D  0x4A00  0x4A00
+KEY_KP_ADD          0x004E  Kp.Add      0x4E2B  0x4E2B  0x4E00  0x4E00
+KEY_KP_RETURN       0xE01C  Kp.Enter    0xE01C  0xE01C  0x1C00  0x1C00
+
+KEY_KP7             0x0047              0x4737  0x4737  0x4700  0x4700
+KEY_KP8             0x0048              0x4838  0x4838  0x4800  0x4800
+KEY_KP9             0x0049              0x4939  0x4939  0x4900  0x4900
+KEY_KP4             0x004B              0x4B34  0x4B34  0x4B00  0x4B00
+KEY_KP5             0x004C              0x4C35  0x4C35  0x4C00  0x4C00
+KEY_KP6             0x004D              0x4D36  0x4D36  0x4D00  0x4D00
+KEY_KP1             0x004F              0x4F31  0x4F31  0x4F00  0x4F00
+KEY_KP2             0x0050              0x5032  0x5032  0x5000  0x5000
+KEY_KP3             0x0051              0x5133  0x5133  0x5100  0x5100
+KEY_KP0             0x0052              0x5230  0x5230  0x5200  0x5200
+
+KEY_KP_DEC          0x0053              0x532E  0x532E  0x5300  0x5300

doc/signal.md

@@ -0,0 +1,49 @@
+# Signal
+
+## Legenda
+
+The **first column** of the table represent the implementation status,
+specifically:
+
+1. Implemented
+2. Tested
+
+If the column is empty it means that it's not implemented yet.
+
+## Implementation Status
+
+```
+ S | Number | Signal    | Standard | Action | Comment
+---+--------+-----------+----------+--------+------------------------------
+   |    1   | SIGHUP    | P1990    | Term   | Hangup detected on controlling terminal or death of controlling process
+   |    2   | SIGINT    | P1990    | Term   | Interrupt from keyboard
+   |    3   | SIGQUIT   | P1990    | Core   | Quit from keyboard
+   |    4   | SIGILL    | P1990    | Core   | Illegal Instruction
+   |    5   | SIGTRAP   | P2001    | Core   | Trace/breakpoint trap
+ 2 |    6   | SIGABRT   | P1990    | Core   | Abort signal from abort(3)
+   |    7   | SIGEMT    |   -      | Term   | Emulator trap
+ 2 |    8   | SIGFPE    | P1990    | Core   | Floating-point exception
+ 2 |    9   | SIGKILL   | P1990    | Term   | Kill signal
+   |   10   | SIGBUS    | P2001    | Core   | Bus error (bad memory access)
+   |   11   | SIGSEGV   | P1990    | Core   | Invalid memory reference
+   |   12   | SIGSYS    | P2001    | Core   | Bad system call (SVr4); see also seccomp(2)
+   |   13   | SIGPIPE   | P1990    | Term   | Broken pipe: write to pipe with no readers; see pipe(7)
+ 2 |   14   | SIGALRM   | P1990    | Term   | Timer signal from alarm(2)
+ 2 |   15   | SIGTERM   | P1990    | Term   | Termination signal
+ 2 |   16   | SIGUSR1   | P1990    | Term   | User-defined signal 1
+ 2 |   17   | SIGUSR2   | P1990    | Term   | User-defined signal 2
+ 1 |   18   | SIGCHLD   | P1990    | Ign    | Child stopped or terminated
+   |   19   | SIGPWR    |   -      | Term   | Power failure (System V)
+   |   20   | SIGWINCH  |   -      | Ign    | Window resize signal (4.3BSD, Sun)
+   |   21   | SIGURG    | P2001    | Ign    | Urgent condition on socket (4.2BSD)
+   |   22   | SIGPOLL   | P2001    | Term   | Pollable event (Sys V); synonym for SIGIO
+ 2 |   23   | SIGSTOP   | P1990    | Stop   | Stop process
+   |   24   | SIGTSTP   | P1990    | Stop   | Stop typed at terminal
+ 2 |   25   | SIGCONT   | P1990    | Cont   | Continue if stopped
+   |   26   | SIGTTIN   | P1990    | Stop   | Terminal input for background process
+   |   27   | SIGTTOU   | P1990    | Stop   | Terminal output for background process
+   |   28   | SIGVTALRM | P2001    | Term   | Virtual alarm clock (4.2BSD)
+ 2 |   29   | SIGPROF   | P2001    | Term   | Profiling timer expired
+   |   30   | SIGXCPU   | P2001    | Core   | CPU time limit exceeded (4.2BSD); see setrlimit(2)
+   |   31   | SIGXFSZ   | P2001    | Core   | File size limit exceeded (4.2BSD); see setrlimit(2)
+```

doc/syscall.md

@@ -0,0 +1,207 @@
+# System Call
+
+## Legenda
+
+The **first column** of the table represent the implementation status,
+specifically:
+
+1. Implemented
+2. Tested
+
+If the column is empty it means that it's not implemented yet.
+
+## Implementation Status
+
+```
+ S | EAX | Name                       | Source                      | EBX                      | ECX                          | EDX                     | ESX             | EDI              |
+---+-----+----------------------------+-----------------------------+--------------------------+------------------------------+-------------------------+-----------------+------------------|
+ 2 | 1   | sys_exit                   | kernel/exit.c               | int                      | -                            | -                       | -               | -                |
+ 2 | 2   | sys_fork                   | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
+ 2 | 3   | sys_read                   | fs/read_write.c             | unsigned int             | char *                       | size_t                  | -               | -                |
+ 2 | 4   | sys_write                  | fs/read_write.c             | unsigned int             | const char *                 | size_t                  | -               | -                |
+ 2 | 5   | sys_open                   | fs/open.c                   | const char *             | int                          | int                     | -               | -                |
+ 2 | 6   | sys_close                  | fs/open.c                   | int                      | -                            | -                       | -               | -                |
+ 2 | 7   | sys_waitpid                | kernel/exit.c               | pid_t                    | unsigned int *               | int                     | -               | -                |
+   | 8   | sys_creat                  | fs/open.c                   | const char *             | int                          | -                       | -               | -                |
+   | 9   | sys_link                   | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
+ 2 | 10  | sys_unlink                 | fs/namei.c                  | const char *             | -                            | -                       | -               | -                |
+ 2 | 11  | sys_execve                 | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
+ 2 | 12  | sys_chdir                  | fs/open.c                   | const char *             | -                            | -                       | -               | -                |
+ 2 | 13  | sys_time                   | kernel/time.c               | int *                    | -                            | -                       | -               | -                |
+   | 14  | sys_mknod                  | fs/namei.c                  | const char *             | int                          | dev_t                   | -               | -                |
+   | 15  | sys_chmod                  | fs/open.c                   | const char *             | mode_t                       | -                       | -               | -                |
+   | 16  | sys_lchown                 | fs/open.c                   | const char *             | uid_t                        | gid_t                   | -               | -                |
+ 2 | 18  | sys_stat                   | fs/stat.c                   | char *                   | struct __old_kernel_stat *   | -                       | -               | -                |
+ 2 | 19  | sys_lseek                  | fs/read_write.c             | unsigned int             | off_t                        | unsigned int            | -               | -                |
+ 2 | 20  | sys_getpid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 21  | sys_mount                  | fs/super.c                  | char *                   | char *                       | char *                  | -               | -                |
+   | 22  | sys_oldumount              | fs/super.c                  | char *                   | -                            | -                       | -               | -                |
+   | 23  | sys_setuid                 | kernel/sys.c                | uid_t                    | -                            | -                       | -               | -                |
+   | 24  | sys_getuid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 25  | sys_stime                  | kernel/time.c               | int *                    | -                            | -                       | -               | -                |
+   | 26  | sys_ptrace                 | arch/i386/kernel/ptrace.c   | long                     | long                         | long                    | long            | -                |
+   | 27  | sys_alarm                  | kernel/sched.c              | unsigned int             | -                            | -                       | -               | -                |
+ 2 | 28  | sys_fstat                  | fs/stat.c                   | unsigned int             | struct __old_kernel_stat *   | -                       | -               | -                |
+   | 29  | sys_pause                  | arch/i386/kernel/sys_i386.c | -                        | -                            | -                       | -               | -                |
+   | 30  | sys_utime                  | fs/open.c                   | char *                   | struct utimbuf *             | -                       | -               | -                |
+   | 33  | sys_access                 | fs/open.c                   | const char *             | int                          | -                       | -               | -                |
+ 1 | 34  | sys_nice                   | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
+   | 36  | sys_sync                   | fs/buffer.c                 | -                        | -                            | -                       | -               | -                |
+ 1 | 37  | sys_kill                   | kernel/signal.c             | int                      | int                          | -                       | -               | -                |
+   | 38  | sys_rename                 | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
+ 2 | 39  | sys_mkdir                  | fs/namei.c                  | const char *             | int                          | -                       | -               | -                |
+ 2 | 40  | sys_rmdir                  | fs/namei.c                  | const char *             | -                            | -                       | -               | -                |
+   | 41  | sys_dup                    | fs/fcntl.c                  | unsigned int             | -                            | -                       | -               | -                |
+   | 42  | sys_pipe                   | arch/i386/kernel/sys_i386.c | unsigned long *          | -                            | -                       | -               | -                |
+   | 43  | sys_times                  | kernel/sys.c                | struct tms *             | -                            | -                       | -               | -                |
+ 2 | 45  | sys_brk                    | mm/mmap.c                   | unsigned long            | -                            | -                       | -               | -                |
+   | 46  | sys_setgid                 | kernel/sys.c                | gid_t                    | -                            | -                       | -               | -                |
+   | 47  | sys_getgid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+ 1 | 48  | sys_signal                 | kernel/signal.c             | int                      | __sighandler_t               | -                       | -               | -                |
+   | 49  | sys_geteuid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 50  | sys_getegid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 51  | sys_acct                   | kernel/acct.c               | const char *             | -                            | -                       | -               | -                |
+   | 52  | sys_umount                 | fs/super.c                  | char *                   | int                          | -                       | -               | -                |
+ 1 | 54  | sys_ioctl                  | fs/ioctl.c                  | unsigned int             | unsigned int                 | unsigned long           | -               | -                |
+   | 55  | sys_fcntl                  | fs/fcntl.c                  | unsigned int             | unsigned int                 | unsigned long           | -               | -                |
+   | 57  | sys_setpgid                | kernel/sys.c                | pid_t                    | pid_t                        | -                       | -               | -                |
+   | 59  | sys_olduname               | arch/i386/kernel/sys_i386.c | struct oldold_utsname *  | -                            | -                       | -               | -                |
+   | 60  | sys_umask                  | kernel/sys.c                | int                      | -                            | -                       | -               | -                |
+   | 61  | sys_chroot                 | fs/open.c                   | const char *             | -                            | -                       | -               | -                |
+   | 62  | sys_ustat                  | fs/super.c                  | dev_t                    | struct ustat *               | -                       | -               | -                |
+   | 63  | sys_dup2                   | fs/fcntl.c                  | unsigned int             | unsigned int                 | -                       | -               | -                |
+ 2 | 64  | sys_getppid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 65  | sys_getpgrp                | kernel/sys.c                | -                        | -                            | -                       | -               | -                |
+   | 66  | sys_setsid                 | kernel/sys.c                | -                        | -                            | -                       | -               | -                |
+ 1 | 67  | sys_sigaction              | arch/i386/kernel/signal.c   | int                      | const struct old_sigaction * | struct old_sigaction *  | -               | -                |
+   | 68  | sys_sgetmask               | kernel/signal.c             | -                        | -                            | -                       | -               | -                |
+   | 69  | sys_ssetmask               | kernel/signal.c             | int                      | -                            | -                       | -               | -                |
+   | 70  | sys_setreuid               | kernel/sys.c                | uid_t                    | uid_t                        | -                       | -               | -                |
+   | 71  | sys_setregid               | kernel/sys.c                | gid_t                    | gid_t                        | -                       | -               | -                |
+   | 72  | sys_sigsuspend             | arch/i386/kernel/signal.c   | int                      | int                          | old_sigset_t            | -               | -                |
+   | 73  | sys_sigpending             | kernel/signal.c             | old_sigset_t *           | -                            | -                       | -               | -                |
+   | 74  | sys_sethostname            | kernel/sys.c                | char *                   | int                          | -                       | -               | -                |
+   | 75  | sys_setrlimit              | kernel/sys.c                | unsigned int             | struct rlimit *              | -                       | -               | -                |
+   | 76  | sys_getrlimit              | kernel/sys.c                | unsigned int             | struct rlimit *              | -                       | -               | -                |
+   | 77  | sys_getrusage              | kernel/sys.c                | int                      | struct rusage *              | -                       | -               | -                |
+   | 78  | sys_gettimeofday           | kernel/time.c               | struct timeval *         | struct timezone *            | -                       | -               | -                |
+   | 79  | sys_settimeofday           | kernel/time.c               | struct timeval *         | struct timezone *            | -                       | -               | -                |
+   | 80  | sys_getgroups              | kernel/sys.c                | int                      | gid_t *                      | -                       | -               | -                |
+   | 81  | sys_setgroups              | kernel/sys.c                | int                      | gid_t *                      | -                       | -               | -                |
+   | 83  | sys_symlink                | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
+   | 84  | sys_lstat                  | fs/stat.c                   | char *                   | struct __old_kernel_stat *   | -                       | -               | -                |
+   | 85  | sys_readlink               | fs/stat.c                   | const char *             | char *                       | int                     | -               | -                |
+   | 86  | sys_uselib                 | fs/exec.c                   | const char *             | -                            | -                       | -               | -                |
+   | 87  | sys_swapon                 | mm/swapfile.c               | const char *             | int                          | -                       | -               | -                |
+ 1 | 88  | sys_reboot                 | kernel/sys.c                | int                      | int                          | int                     | void *          | -                |
+ 1 | 89  | old_readdir                | fs/readdir.c                | unsigned int             | void *                       | unsigned int            | -               | -                |
+   | 90  | old_mmap                   | arch/i386/kernel/sys_i386.c | struct mmap_arg_struct * | -                            | -                       | -               | -                |
+   | 91  | sys_munmap                 | mm/mmap.c                   | unsigned long            | size_t                       | -                       | -               | -                |
+   | 92  | sys_truncate               | fs/open.c                   | const char *             | unsigned long                | -                       | -               | -                |
+   | 93  | sys_ftruncate              | fs/open.c                   | unsigned int             | unsigned long                | -                       | -               | -                |
+   | 94  | sys_fchmod                 | fs/open.c                   | unsigned int             | mode_t                       | -                       | -               | -                |
+   | 95  | sys_fchown                 | fs/open.c                   | unsigned int             | uid_t                        | gid_t                   | -               | -                |
+   | 96  | sys_getpriority            | kernel/sys.c                | int                      | int                          | -                       | -               | -                |
+   | 97  | sys_setpriority            | kernel/sys.c                | int                      | int                          | int                     | -               | -                |
+   | 99  | sys_statfs                 | fs/open.c                   | const char *             | struct statfs *              | -                       | -               | -                |
+   | 100 | sys_fstatfs                | fs/open.c                   | unsigned int             | struct statfs *              | -                       | -               | -                |
+   | 101 | sys_ioperm                 | arch/i386/kernel/ioport.c   | unsigned long            | unsigned long                | int                     | -               | -                |
+   | 102 | sys_socketcall             | net/socket.c                | int                      | unsigned long *              | -                       | -               | -                |
+   | 103 | sys_syslog                 | kernel/printk.c             | int                      | char *                       | int                     | -               | -                |
+   | 104 | sys_setitimer              | kernel/itimer.c             | int                      | struct itimerval *           | struct itimerval *      | -               | -                |
+   | 105 | sys_getitimer              | kernel/itimer.c             | int                      | struct itimerval *           | -                       | -               | -                |
+   | 106 | sys_newstat                | fs/stat.c                   | char *                   | struct stat *                | -                       | -               | -                |
+   | 107 | sys_newlstat               | fs/stat.c                   | char *                   | struct stat *                | -                       | -               | -                |
+   | 108 | sys_newfstat               | fs/stat.c                   | unsigned int             | struct stat *                | -                       | -               | -                |
+ 1 | 109 | sys_uname                  | arch/i386/kernel/sys_i386.c | struct old_utsname *     | -                            | -                       | -               | -                |
+   | 110 | sys_iopl                   | arch/i386/kernel/ioport.c   | unsigned long            | -                            | -                       | -               | -                |
+   | 111 | sys_vhangup                | fs/open.c                   | -                        | -                            | -                       | -               | -                |
+   | 112 | sys_idle                   | arch/i386/kernel/process.c  | -                        | -                            | -                       | -               | -                |
+   | 113 | sys_vm86old                | arch/i386/kernel/vm86.c     | unsigned long            | struct vm86plus_struct *     | -                       | -               | -                |
+   | 114 | sys_wait4                  | kernel/exit.c               | pid_t                    | unsigned long *              | int options             | struct rusage * | -                |
+   | 115 | sys_swapoff                | mm/swapfile.c               | const char *             | -                            | -                       | -               | -                |
+   | 116 | sys_sysinfo                | kernel/info.c               | struct sysinfo *         | -                            | -                       | -               | -                |
+ * | 117 | sys_ipc(*Note)             | arch/i386/kernel/sys_i386.c | uint                     | int                          | int                     | int             | void *           |
+   | 118 | sys_fsync                  | fs/buffer.c                 | unsigned int             | -                            | -                       | -               | -                |
+   | 119 | sys_sigreturn              | arch/i386/kernel/signal.c   | unsigned long            | -                            | -                       | -               | -                |
+   | 120 | sys_clone                  | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
+   | 121 | sys_setdomainname          | kernel/sys.c                | char *                   | int                          | -                       | -               | -                |
+   | 122 | sys_newuname               | kernel/sys.c                | struct new_utsname *     | -                            | -                       | -               | -                |
+   | 123 | sys_modify_ldt             | arch/i386/kernel/ldt.c      | int                      | void *                       | unsigned long           | -               | -                |
+   | 124 | sys_adjtimex               | kernel/time.c               | struct timex *           | -                            | -                       | -               | -                |
+   | 125 | sys_mprotect               | mm/mprotect.c               | unsigned long            | size_t                       | unsigned long           | -               | -                |
+ 1 | 126 | sys_sigprocmask            | kernel/signal.c             | int                      | old_sigset_t *               | old_sigset_t *          | -               | -                |
+   | 127 | sys_create_module          | kernel/module.c             | const char *             | size_t                       | -                       | -               | -                |
+   | 128 | sys_init_module            | kernel/module.c             | const char *             | struct module *              | -                       | -               | -                |
+   | 129 | sys_delete_module          | kernel/module.c             | const char *             | -                            | -                       | -               | -                |
+   | 130 | sys_get_kernel_syms        | kernel/module.c             | struct kernel_sym *      | -                            | -                       | -               | -                |
+   | 131 | sys_quotactl               | fs/dquot.c                  | int                      | const char *                 | int                     | caddr_t         | -                |
+   | 132 | sys_getpgid                | kernel/sys.c                | pid_t                    | -                            | -                       | -               | -                |
+ 1 | 133 | sys_fchdir                 | fs/open.c                   | unsigned int             | -                            | -                       | -               | -                |
+   | 134 | sys_bdflush                | fs/buffer.c                 | int                      | long                         | -                       | -               | -                |
+   | 135 | sys_sysfs                  | fs/super.c                  | int                      | unsigned long                | unsigned long           | -               | -                |
+   | 136 | sys_personality            | kernel/exec_domain.c        | unsigned long            | -                            | -                       | -               | -                |
+   | 138 | sys_setfsuid               | kernel/sys.c                | uid_t                    | -                            | -                       | -               | -                |
+   | 139 | sys_setfsgid               | kernel/sys.c                | gid_t                    | -                            | -                       | -               | -                |
+   | 140 | sys_llseek                 | fs/read_write.c             | unsigned int             | unsigned long                | unsigned long           | loff_t *        | unsigned int     |
+ 2 | 141 | sys_getdents               | fs/readdir.c                | unsigned int             | void *                       | unsigned int            | -               | -                |
+   | 142 | sys_select                 | fs/select.c                 | int                      | fd_set *                     | fd_set *                | fd_set *        | struct timeval * |
+   | 143 | sys_flock                  | fs/locks.c                  | unsigned int             | unsigned int                 | -                       | -               | -                |
+   | 144 | sys_msync                  | mm/filemap.c                | unsigned long            | size_t                       | int                     | -               | -                |
+   | 145 | sys_readv                  | fs/read_write.c             | unsigned long            | const struct iovec *         | unsigned long           | -               | -                |
+   | 146 | sys_writev                 | fs/read_write.c             | unsigned long            | const struct iovec *         | unsigned long           | -               | -                |
+   | 147 | sys_getsid                 | kernel/sys.c                | pid_t                    | -                            | -                       | -               | -                |
+   | 148 | sys_fdatasync              | fs/buffer.c                 | unsigned int             | -                            | -                       | -               | -                |
+   | 149 | sys_sysctl                 | kernel/sysctl.c             | struct __sysctl_args *   | -                            | -                       | -               | -                |
+   | 150 | sys_mlock                  | mm/mlock.c                  | unsigned long            | size_t                       | -                       | -               | -                |
+   | 151 | sys_munlock                | mm/mlock.c                  | unsigned long            | size_t                       | -                       | -               | -                |
+   | 152 | sys_mlockall               | mm/mlock.c                  | int                      | -                            | -                       | -               | -                |
+   | 153 | sys_munlockall             | mm/mlock.c                  | -                        | -                            | -                       | -               | -                |
+ 1 | 154 | sys_sched_setparam         | kernel/sched.c              | pid_t                    | struct sched_param *         | -                       | -               | -                |
+ 1 | 155 | sys_sched_getparam         | kernel/sched.c              | pid_t                    | struct sched_param *         | -                       | -               | -                |
+   | 156 | sys_sched_setscheduler     | kernel/sched.c              | pid_t                    | int                          | struct sched_param *    | -               | -                |
+   | 157 | sys_sched_getscheduler     | kernel/sched.c              | pid_t                    | -                            | -                       | -               | -                |
+   | 158 | sys_sched_yield            | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
+   | 159 | sys_sched_get_priority_max | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
+   | 160 | sys_sched_get_priority_min | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
+   | 161 | sys_sched_rr_get_interval  | kernel/sched.c              | pid_t                    | struct timespec *            | -                       | -               | -                |
+   | 162 | sys_nanosleep              | kernel/sched.c              | struct timespec *        | struct timespec *            | -                       | -               | -                |
+   | 163 | sys_mremap                 | mm/mremap.c                 | unsigned long            | unsigned long                | unsigned long           | unsigned long   | -                |
+   | 164 | sys_setresuid              | kernel/sys.c                | uid_t                    | uid_t                        | uid_t                   | -               | -                |
+   | 165 | sys_getresuid              | kernel/sys.c                | uid_t *                  | uid_t *                      | uid_t *                 | -               | -                |
+   | 166 | sys_vm86                   | arch/i386/kernel/vm86.c     | struct vm86_struct *     | -                            | -                       | -               | -                |
+   | 167 | sys_query_module           | kernel/module.c             | const char *             | int                          | char *                  | size_t          | size_t *         |
+   | 168 | sys_poll                   | fs/select.c                 | struct pollfd *          | unsigned int                 | long                    | -               | -                |
+   | 169 | sys_nfsservctl             | fs/filesystems.c            | int                      | void *                       | void *                  | -               | -                |
+   | 170 | sys_setresgid              | kernel/sys.c                | gid_t                    | gid_t                        | gid_t                   | -               | -                |
+   | 171 | sys_getresgid              | kernel/sys.c                | gid_t *                  | gid_t *                      | gid_t *                 | -               | -                |
+   | 172 | sys_prctl                  | kernel/sys.c                | int                      | unsigned long                | unsigned long           | unsigned long   | unsigned long    |
+   | 173 | sys_rt_sigreturn           | arch/i386/kernel/signal.c   | unsigned long            | -                            | -                       | -               | -                |
+   | 174 | sys_rt_sigaction           | kernel/signal.c             | int                      | const struct sigaction *     | struct sigaction *      | size_t          | -                |
+   | 175 | sys_rt_sigprocmask         | kernel/signal.c             | int                      | sigset_t *                   | sigset_t *              | size_t          | -                |
+   | 176 | sys_rt_sigpending          | kernel/signal.c             | sigset_t *               | size_t                       | -                       | -               | -                |
+   | 177 | sys_rt_sigtimedwait        | kernel/signal.c             | const sigset_t *         | siginfo_t *                  | const struct timespec * | size_t          | -                |
+   | 178 | sys_rt_sigqueueinfo        | kernel/signal.c             | int                      | int                          | siginfo_t *             | -               | -                |
+   | 179 | sys_rt_sigsuspend          | arch/i386/kernel/signal.c   | sigset_t *               | size_t                       | -                       | -               | -                |
+   | 180 | sys_pread                  | fs/read_write.c             | unsigned int             | char *                       | size_t                  | loff_t          | -                |
+   | 181 | sys_pwrite                 | fs/read_write.c             | unsigned int             | const char *                 | size_t                  | loff_t          | -                |
+   | 182 | sys_chown                  | fs/open.c                   | const char *             | uid_t                        | gid_t                   | -               | -                |
+ 1 | 183 | sys_getcwd                 | fs/dcache.c                 | char *                   | unsigned long                | -                       | -               | -                |
+   | 184 | sys_capget                 | kernel/capability.c         | cap_user_header_t        | cap_user_data_t              | -                       | -               | -                |
+   | 185 | sys_capset                 | kernel/capability.c         | cap_user_header_t        | const cap_user_data_t        | -                       | -               | -                |
+   | 186 | sys_sigaltstack            | arch/i386/kernel/signal.c   | const stack_t *          | stack_t *                    | -                       | -               | -                |
+   | 187 | sys_sendfile               | mm/filemap.c                | int                      | int                          | off_t *                 | size_t          | -                |
+   |     |                            |                             |                          |                              |                         |                 |                  |
+ 2 | 188 | sys_waitperiod             | kernel/sched.c              |                          |                              |                         |                 |                  |
+   | 189 | sys_msgctl                 |                             | int                      |                              |                         |                 |                  |
+   | 190 | sys_msgget                 |                             |                          |                              |                         |                 |                  |
+   | 191 | sys_msgrcv                 |                             |                          |                              |                         |                 |                  |
+   | 192 | sys_msgsnd                 |                             |                          |                              |                         |                 |                  |
+   | 193 | sys_semctl                 |                             |                          |                              |                         |                 |                  |
+   | 194 | sys_semget                 |                             |                          |                              |                         |                 |                  |
+   | 195 | sys_semop                  |                             |                          |                              |                         |                 |                  |
+   | 196 | sys_shmat                  |                             |                          |                              |                         |                 |                  |
+   | 197 | sys_shmctl                 |                             |                          |                              |                         |                 |                  |
+   | 198 | sys_shmdt                  |                             |                          |                              |                         |                 |                  |
+   | 199 | sys_shmget                 |                             |                          |                              |                         |                 |                  |
+```

doc/syscall.txt

@@ -1,181 +0,0 @@
-| EAX | Name                       | Source                      | EBX                      | ECX                          | EDX                     | ESX             | EDI              |
-|:----|:---------------------------|:----------------------------|:-------------------------|:-----------------------------|:------------------------|:----------------|:-----------------|
-| 1   | sys_exit                   | kernel/exit.c               | int                      | -                            | -                       | -               | -                |
-| 2   | sys_fork                   | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
-| 3   | sys_read                   | fs/read_write.c             | unsigned int             | char *                       | size_t                  | -               | -                |
-| 4   | sys_write                  | fs/read_write.c             | unsigned int             | const char *                 | size_t                  | -               | -                |
-| 5   | sys_open                   | fs/open.c                   | const char *             | int                          | int                     | -               | -                |
-| 6   | sys_close                  | fs/open.c                   | unsigned int             | -                            | -                       | -               | -                |
-| 7   | sys_waitpid                | kernel/exit.c               | pid_t                    | unsigned int *               | int                     | -               | -                |
-| 8   | sys_creat                  | fs/open.c                   | const char *             | int                          | -                       | -               | -                |
-| 9   | sys_link                   | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
-| 10  | sys_unlink                 | fs/namei.c                  | const char *             | -                            | -                       | -               | -                |
-| 11  | sys_execve                 | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
-| 12  | sys_chdir                  | fs/open.c                   | const char *             | -                            | -                       | -               | -                |
-| 13  | sys_time                   | kernel/time.c               | int *                    | -                            | -                       | -               | -                |
-| 14  | sys_mknod                  | fs/namei.c                  | const char *             | int                          | dev_t                   | -               | -                |
-| 15  | sys_chmod                  | fs/open.c                   | const char *             | mode_t                       | -                       | -               | -                |
-| 16  | sys_lchown                 | fs/open.c                   | const char *             | uid_t                        | gid_t                   | -               | -                |
-| 18  | sys_stat                   | fs/stat.c                   | char *                   | struct __old_kernel_stat *   | -                       | -               | -                |
-| 19  | sys_lseek                  | fs/read_write.c             | unsigned int             | off_t                        | unsigned int            | -               | -                |
-| 20  | sys_getpid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 21  | sys_mount                  | fs/super.c                  | char *                   | char *                       | char *                  | -               | -                |
-| 22  | sys_oldumount              | fs/super.c                  | char *                   | -                            | -                       | -               | -                |
-| 23  | sys_setuid                 | kernel/sys.c                | uid_t                    | -                            | -                       | -               | -                |
-| 24  | sys_getuid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 25  | sys_stime                  | kernel/time.c               | int *                    | -                            | -                       | -               | -                |
-| 26  | sys_ptrace                 | arch/i386/kernel/ptrace.c   | long                     | long                         | long                    | long            | -                |
-| 27  | sys_alarm                  | kernel/sched.c              | unsigned int             | -                            | -                       | -               | -                |
-| 28  | sys_fstat                  | fs/stat.c                   | unsigned int             | struct __old_kernel_stat *   | -                       | -               | -                |
-| 29  | sys_pause                  | arch/i386/kernel/sys_i386.c | -                        | -                            | -                       | -               | -                |
-| 30  | sys_utime                  | fs/open.c                   | char *                   | struct utimbuf *             | -                       | -               | -                |
-| 33  | sys_access                 | fs/open.c                   | const char *             | int                          | -                       | -               | -                |
-| 34  | sys_nice                   | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
-| 36  | sys_sync                   | fs/buffer.c                 | -                        | -                            | -                       | -               | -                |
-| 37  | sys_kill                   | kernel/signal.c             | int                      | int                          | -                       | -               | -                |
-| 38  | sys_rename                 | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
-| 39  | sys_mkdir                  | fs/namei.c                  | const char *             | int                          | -                       | -               | -                |
-| 40  | sys_rmdir                  | fs/namei.c                  | const char *             | -                            | -                       | -               | -                |
-| 41  | sys_dup                    | fs/fcntl.c                  | unsigned int             | -                            | -                       | -               | -                |
-| 42  | sys_pipe                   | arch/i386/kernel/sys_i386.c | unsigned long *          | -                            | -                       | -               | -                |
-| 43  | sys_times                  | kernel/sys.c                | struct tms *             | -                            | -                       | -               | -                |
-| 45  | sys_brk                    | mm/mmap.c                   | unsigned long            | -                            | -                       | -               | -                |
-| 46  | sys_setgid                 | kernel/sys.c                | gid_t                    | -                            | -                       | -               | -                |
-| 47  | sys_getgid                 | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 48  | sys_signal                 | kernel/signal.c             | int                      | __sighandler_t               | -                       | -               | -                |
-| 49  | sys_geteuid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 50  | sys_getegid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 51  | sys_acct                   | kernel/acct.c               | const char *             | -                            | -                       | -               | -                |
-| 52  | sys_umount                 | fs/super.c                  | char *                   | int                          | -                       | -               | -                |
-| 54  | sys_ioctl                  | fs/ioctl.c                  | unsigned int             | unsigned int                 | unsigned long           | -               | -                |
-| 55  | sys_fcntl                  | fs/fcntl.c                  | unsigned int             | unsigned int                 | unsigned long           | -               | -                |
-| 57  | sys_setpgid                | kernel/sys.c                | pid_t                    | pid_t                        | -                       | -               | -                |
-| 59  | sys_olduname               | arch/i386/kernel/sys_i386.c | struct oldold_utsname *  | -                            | -                       | -               | -                |
-| 60  | sys_umask                  | kernel/sys.c                | int                      | -                            | -                       | -               | -                |
-| 61  | sys_chroot                 | fs/open.c                   | const char *             | -                            | -                       | -               | -                |
-| 62  | sys_ustat                  | fs/super.c                  | dev_t                    | struct ustat *               | -                       | -               | -                |
-| 63  | sys_dup2                   | fs/fcntl.c                  | unsigned int             | unsigned int                 | -                       | -               | -                |
-| 64  | sys_getppid                | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 65  | sys_getpgrp                | kernel/sys.c                | -                        | -                            | -                       | -               | -                |
-| 66  | sys_setsid                 | kernel/sys.c                | -                        | -                            | -                       | -               | -                |
-| 67  | sys_sigaction              | arch/i386/kernel/signal.c   | int                      | const struct old_sigaction * | struct old_sigaction *  | -               | -                |
-| 68  | sys_sgetmask               | kernel/signal.c             | -                        | -                            | -                       | -               | -                |
-| 69  | sys_ssetmask               | kernel/signal.c             | int                      | -                            | -                       | -               | -                |
-| 70  | sys_setreuid               | kernel/sys.c                | uid_t                    | uid_t                        | -                       | -               | -                |
-| 71  | sys_setregid               | kernel/sys.c                | gid_t                    | gid_t                        | -                       | -               | -                |
-| 72  | sys_sigsuspend             | arch/i386/kernel/signal.c   | int                      | int                          | old_sigset_t            | -               | -                |
-| 73  | sys_sigpending             | kernel/signal.c             | old_sigset_t *           | -                            | -                       | -               | -                |
-| 74  | sys_sethostname            | kernel/sys.c                | char *                   | int                          | -                       | -               | -                |
-| 75  | sys_setrlimit              | kernel/sys.c                | unsigned int             | struct rlimit *              | -                       | -               | -                |
-| 76  | sys_getrlimit              | kernel/sys.c                | unsigned int             | struct rlimit *              | -                       | -               | -                |
-| 77  | sys_getrusage              | kernel/sys.c                | int                      | struct rusage *              | -                       | -               | -                |
-| 78  | sys_gettimeofday           | kernel/time.c               | struct timeval *         | struct timezone *            | -                       | -               | -                |
-| 79  | sys_settimeofday           | kernel/time.c               | struct timeval *         | struct timezone *            | -                       | -               | -                |
-| 80  | sys_getgroups              | kernel/sys.c                | int                      | gid_t *                      | -                       | -               | -                |
-| 81  | sys_setgroups              | kernel/sys.c                | int                      | gid_t *                      | -                       | -               | -                |
-
-| 83  | sys_symlink                | fs/namei.c                  | const char *             | const char *                 | -                       | -               | -                |
-| 84  | sys_lstat                  | fs/stat.c                   | char *                   | struct __old_kernel_stat *   | -                       | -               | -                |
-| 85  | sys_readlink               | fs/stat.c                   | const char *             | char *                       | int                     | -               | -                |
-| 86  | sys_uselib                 | fs/exec.c                   | const char *             | -                            | -                       | -               | -                |
-| 87  | sys_swapon                 | mm/swapfile.c               | const char *             | int                          | -                       | -               | -                |
-| 88  | sys_reboot                 | kernel/sys.c                | int                      | int                          | int                     | void *          | -                |
-| 89  | old_readdir                | fs/readdir.c                | unsigned int             | void *                       | unsigned int            | -               | -                |
-| 90  | old_mmap                   | arch/i386/kernel/sys_i386.c | struct mmap_arg_struct * | -                            | -                       | -               | -                |
-| 91  | sys_munmap                 | mm/mmap.c                   | unsigned long            | size_t                       | -                       | -               | -                |
-| 92  | sys_truncate               | fs/open.c                   | const char *             | unsigned long                | -                       | -               | -                |
-| 93  | sys_ftruncate              | fs/open.c                   | unsigned int             | unsigned long                | -                       | -               | -                |
-| 94  | sys_fchmod                 | fs/open.c                   | unsigned int             | mode_t                       | -                       | -               | -                |
-| 95  | sys_fchown                 | fs/open.c                   | unsigned int             | uid_t                        | gid_t                   | -               | -                |
-| 96  | sys_getpriority            | kernel/sys.c                | int                      | int                          | -                       | -               | -                |
-| 97  | sys_setpriority            | kernel/sys.c                | int                      | int                          | int                     | -               | -                |
-| 99  | sys_statfs                 | fs/open.c                   | const char *             | struct statfs *              | -                       | -               | -                |
-| 100 | sys_fstatfs                | fs/open.c                   | unsigned int             | struct statfs *              | -                       | -               | -                |
-| 101 | sys_ioperm                 | arch/i386/kernel/ioport.c   | unsigned long            | unsigned long                | int                     | -               | -                |
-| 102 | sys_socketcall             | net/socket.c                | int                      | unsigned long *              | -                       | -               | -                |
-| 103 | sys_syslog                 | kernel/printk.c             | int                      | char *                       | int                     | -               | -                |
-| 104 | sys_setitimer              | kernel/itimer.c             | int                      | struct itimerval *           | struct itimerval *      | -               | -                |
-| 105 | sys_getitimer              | kernel/itimer.c             | int                      | struct itimerval *           | -                       | -               | -                |
-| 106 | sys_newstat                | fs/stat.c                   | char *                   | struct stat *                | -                       | -               | -                |
-| 107 | sys_newlstat               | fs/stat.c                   | char *                   | struct stat *                | -                       | -               | -                |
-| 108 | sys_newfstat               | fs/stat.c                   | unsigned int             | struct stat *                | -                       | -               | -                |
-| 109 | sys_uname                  | arch/i386/kernel/sys_i386.c | struct old_utsname *     | -                            | -                       | -               | -                |
-| 110 | sys_iopl                   | arch/i386/kernel/ioport.c   | unsigned long            | -                            | -                       | -               | -                |
-| 111 | sys_vhangup                | fs/open.c                   | -                        | -                            | -                       | -               | -                |
-| 112 | sys_idle                   | arch/i386/kernel/process.c  | -                        | -                            | -                       | -               | -                |
-| 113 | sys_vm86old                | arch/i386/kernel/vm86.c     | unsigned long            | struct vm86plus_struct *     | -                       | -               | -                |
-| 114 | sys_wait4                  | kernel/exit.c               | pid_t                    | unsigned long *              | int options             | struct rusage * | -                |
-| 115 | sys_swapoff                | mm/swapfile.c               | const char *             | -                            | -                       | -               | -                |
-| 116 | sys_sysinfo                | kernel/info.c               | struct sysinfo *         | -                            | -                       | -               | -                |
-| 117 | sys_ipc(*Note)             | arch/i386/kernel/sys_i386.c | uint                     | int                          | int                     | int             | void *           |
-| 118 | sys_fsync                  | fs/buffer.c                 | unsigned int             | -                            | -                       | -               | -                |
-| 119 | sys_sigreturn              | arch/i386/kernel/signal.c   | unsigned long            | -                            | -                       | -               | -                |
-| 120 | sys_clone                  | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
-| 121 | sys_setdomainname          | kernel/sys.c                | char *                   | int                          | -                       | -               | -                |
-| 122 | sys_newuname               | kernel/sys.c                | struct new_utsname *     | -                            | -                       | -               | -                |
-| 123 | sys_modify_ldt             | arch/i386/kernel/ldt.c      | int                      | void *                       | unsigned long           | -               | -                |
-| 124 | sys_adjtimex               | kernel/time.c               | struct timex *           | -                            | -                       | -               | -                |
-| 125 | sys_mprotect               | mm/mprotect.c               | unsigned long            | size_t                       | unsigned long           | -               | -                |
-| 126 | sys_sigprocmask            | kernel/signal.c             | int                      | old_sigset_t *               | old_sigset_t *          | -               | -                |
-| 127 | sys_create_module          | kernel/module.c             | const char *             | size_t                       | -                       | -               | -                |
-| 128 | sys_init_module            | kernel/module.c             | const char *             | struct module *              | -                       | -               | -                |
-| 129 | sys_delete_module          | kernel/module.c             | const char *             | -                            | -                       | -               | -                |
-| 130 | sys_get_kernel_syms        | kernel/module.c             | struct kernel_sym *      | -                            | -                       | -               | -                |
-| 131 | sys_quotactl               | fs/dquot.c                  | int                      | const char *                 | int                     | caddr_t         | -                |
-| 132 | sys_getpgid                | kernel/sys.c                | pid_t                    | -                            | -                       | -               | -                |
-| 133 | sys_fchdir                 | fs/open.c                   | unsigned int             | -                            | -                       | -               | -                |
-| 134 | sys_bdflush                | fs/buffer.c                 | int                      | long                         | -                       | -               | -                |
-| 135 | sys_sysfs                  | fs/super.c                  | int                      | unsigned long                | unsigned long           | -               | -                |
-| 136 | sys_personality            | kernel/exec_domain.c        | unsigned long            | -                            | -                       | -               | -                |
-| 138 | sys_setfsuid               | kernel/sys.c                | uid_t                    | -                            | -                       | -               | -                |
-| 139 | sys_setfsgid               | kernel/sys.c                | gid_t                    | -                            | -                       | -               | -                |
-| 140 | sys_llseek                 | fs/read_write.c             | unsigned int             | unsigned long                | unsigned long           | loff_t *        | unsigned int     |
-| 141 | sys_getdents               | fs/readdir.c                | unsigned int             | void *                       | unsigned int            | -               | -                |
-| 142 | sys_select                 | fs/select.c                 | int                      | fd_set *                     | fd_set *                | fd_set *        | struct timeval * |
-| 143 | sys_flock                  | fs/locks.c                  | unsigned int             | unsigned int                 | -                       | -               | -                |
-| 144 | sys_msync                  | mm/filemap.c                | unsigned long            | size_t                       | int                     | -               | -                |
-| 145 | sys_readv                  | fs/read_write.c             | unsigned long            | const struct iovec *         | unsigned long           | -               | -                |
-| 146 | sys_writev                 | fs/read_write.c             | unsigned long            | const struct iovec *         | unsigned long           | -               | -                |
-| 147 | sys_getsid                 | kernel/sys.c                | pid_t                    | -                            | -                       | -               | -                |
-| 148 | sys_fdatasync              | fs/buffer.c                 | unsigned int             | -                            | -                       | -               | -                |
-| 149 | sys_sysctl                 | kernel/sysctl.c             | struct __sysctl_args *   | -                            | -                       | -               | -                |
-| 150 | sys_mlock                  | mm/mlock.c                  | unsigned long            | size_t                       | -                       | -               | -                |
-| 151 | sys_munlock                | mm/mlock.c                  | unsigned long            | size_t                       | -                       | -               | -                |
-| 152 | sys_mlockall               | mm/mlock.c                  | int                      | -                            | -                       | -               | -                |
-| 153 | sys_munlockall             | mm/mlock.c                  | -                        | -                            | -                       | -               | -                |
-| 154 | sys_sched_setparam         | kernel/sched.c              | pid_t                    | struct sched_param *         | -                       | -               | -                |
-| 155 | sys_sched_getparam         | kernel/sched.c              | pid_t                    | struct sched_param *         | -                       | -               | -                |
-| 156 | sys_sched_setscheduler     | kernel/sched.c              | pid_t                    | int                          | struct sched_param *    | -               | -                |
-| 157 | sys_sched_getscheduler     | kernel/sched.c              | pid_t                    | -                            | -                       | -               | -                |
-| 158 | sys_sched_yield            | kernel/sched.c              | -                        | -                            | -                       | -               | -                |
-| 159 | sys_sched_get_priority_max | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
-| 160 | sys_sched_get_priority_min | kernel/sched.c              | int                      | -                            | -                       | -               | -                |
-| 161 | sys_sched_rr_get_interval  | kernel/sched.c              | pid_t                    | struct timespec *            | -                       | -               | -                |
-| 162 | sys_nanosleep              | kernel/sched.c              | struct timespec *        | struct timespec *            | -                       | -               | -                |
-| 163 | sys_mremap                 | mm/mremap.c                 | unsigned long            | unsigned long                | unsigned long           | unsigned long   | -                |
-| 164 | sys_setresuid              | kernel/sys.c                | uid_t                    | uid_t                        | uid_t                   | -               | -                |
-| 165 | sys_getresuid              | kernel/sys.c                | uid_t *                  | uid_t *                      | uid_t *                 | -               | -                |
-| 166 | sys_vm86                   | arch/i386/kernel/vm86.c     | struct vm86_struct *     | -                            | -                       | -               | -                |
-| 167 | sys_query_module           | kernel/module.c             | const char *             | int                          | char *                  | size_t          | size_t *         |
-| 168 | sys_poll                   | fs/select.c                 | struct pollfd *          | unsigned int                 | long                    | -               | -                |
-| 169 | sys_nfsservctl             | fs/filesystems.c            | int                      | void *                       | void *                  | -               | -                |
-| 170 | sys_setresgid              | kernel/sys.c                | gid_t                    | gid_t                        | gid_t                   | -               | -                |
-| 171 | sys_getresgid              | kernel/sys.c                | gid_t *                  | gid_t *                      | gid_t *                 | -               | -                |
-| 172 | sys_prctl                  | kernel/sys.c                | int                      | unsigned long                | unsigned long           | unsigned long   | unsigned long    |
-| 173 | sys_rt_sigreturn           | arch/i386/kernel/signal.c   | unsigned long            | -                            | -                       | -               | -                |
-| 174 | sys_rt_sigaction           | kernel/signal.c             | int                      | const struct sigaction *     | struct sigaction *      | size_t          | -                |
-| 175 | sys_rt_sigprocmask         | kernel/signal.c             | int                      | sigset_t *                   | sigset_t *              | size_t          | -                |
-| 176 | sys_rt_sigpending          | kernel/signal.c             | sigset_t *               | size_t                       | -                       | -               | -                |
-| 177 | sys_rt_sigtimedwait        | kernel/signal.c             | const sigset_t *         | siginfo_t *                  | const struct timespec * | size_t          | -                |
-| 178 | sys_rt_sigqueueinfo        | kernel/signal.c             | int                      | int                          | siginfo_t *             | -               | -                |
-| 179 | sys_rt_sigsuspend          | arch/i386/kernel/signal.c   | sigset_t *               | size_t                       | -                       | -               | -                |
-| 180 | sys_pread                  | fs/read_write.c             | unsigned int             | char *                       | size_t                  | loff_t          | -                |
-| 181 | sys_pwrite                 | fs/read_write.c             | unsigned int             | const char *                 | size_t                  | loff_t          | -                |
-| 182 | sys_chown                  | fs/open.c                   | const char *             | uid_t                        | gid_t                   | -               | -                |
-| 183 | sys_getcwd                 | fs/dcache.c                 | char *                   | unsigned long                | -                       | -               | -                |
-| 184 | sys_capget                 | kernel/capability.c         | cap_user_header_t        | cap_user_data_t              | -                       | -               | -                |
-| 185 | sys_capset                 | kernel/capability.c         | cap_user_header_t        | const cap_user_data_t        | -                       | -               | -                |
-| 186 | sys_sigaltstack            | arch/i386/kernel/signal.c   | const stack_t *          | stack_t *                    | -                       | -               | -                |
-| 187 | sys_sendfile               | mm/filemap.c                | int                      | int                          | off_t *                 | size_t          | -                |
-| 190 | sys_vfork                  | arch/i386/kernel/process.c  | struct pt_regs           | -                            | -                       | -               | -                |
-|     |                            |                             |                          |                              |                         |                 |                  |

files/etc/group

@@ -0,0 +1,2 @@
+root:x:0:user,root,marco
+user:x:1000:banana,marco

files/etc/hostname

@@ -0,0 +1 @@
+avalon

files/etc/motd

@@ -0,0 +1 @@
+Call `man` to have a list of all the commands.

files/etc/passwd

@@ -0,0 +1,2 @@
+root:root:0:0:Root User:/root:/bin/shell
+user:user:1000:1000:Normal User:/home/user:/bin/shell

files/passwd

@@ -1,3 +0,0 @@
-root:password
-user:computer
-asd:asd

files/prog/more.c

@@ -1,28 +0,0 @@
-#include <stdio.h>
-#include <fcntl.h>
-
-void main(int argc, char ** argv)
-{
-    if (argc == 2)
-    {
-        // Try to open the file.
-        int fd = open(argv[1], O_RDONLY, 42);
-        if (fd > -1)
-        {
-            char c;
-            // Put on the standard output the characters.
-            while (read(fd, &c, 1)) putchar(c);
-            putchar('\n');
-            putchar('\n');
-            close(fd);
-        }
-        else
-        {
-            printf("%s: cannot find the file.\n\n", argv[1]);
-        }
-    }
-    else
-    {
-        printf("Usage: more file\n\n");
-    }
-}

files/test2.txt

@@ -1 +1,3 @@
 come va ?
+AAA
+

files/usr/share/man/cat.man

@@ -0,0 +1,8 @@
+SYNOPSIS
+    cat [FILE]
+
+DESCRIPTION
+    Prints the content of the given file.
+
+OPTIONS
+    -h --help : shows command help.

files/usr/share/man/clear.man

@@ -0,0 +1,5 @@
+SYNOPSIS
+    clear
+
+DESCRIPTION
+    Clears the screen.

files/usr/share/man/cpuid.man

@@ -0,0 +1,5 @@
+SYNOPSIS
+    cpuid
+
+DESCRIPTION
+    Not currently implemented.

files/usr/share/man/date.man

@@ -0,0 +1,5 @@
+SYNOPSIS
+    date
+
+DESCRIPTION
+    Shows the current date.

files/usr/share/man/echo.man

@@ -0,0 +1,6 @@
+SYNOPSIS
+    echo [STRING]
+
+DESCRIPTION
+    Displays a line of text.
+    

files/usr/share/man/ls.man

@@ -0,0 +1,12 @@
+SYNOPSIS
+    ls [OPTIONS] [FILE/FOLDER]
+
+DESCRIPTION
+    List information about the given file, or the files contained in the given
+    folder. If not argument is provided it will list information about files
+    inside the current folder.
+    
+OPTIONS
+    -h --help : shows command help.
+    -a --all  : list all entries.
+    -l --long : show the entries as a detailed long list.

initscp/CMakeLists.txt

@@ -1,28 +0,0 @@
-# ------------------------------------------------------------------------------
-# Initialize the project.
-project(initfscp C ASM)
-
-# ------------------------------------------------------------------------------
-# Set the project name.
-set(PROJECT_NAME initfscp)
-
-# ------------------------------------------------------------------------------
-# Set the compiler options (original).
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g3")
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ggdb")
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
-
-# ------------------------------------------------------------------------------
-# Add the includes.
-include_directories(inc)
-
-# ------------------------------------------------------------------------------
-# Add the source files.
-set(SOURCE_FILES src/initfscp.c)
-
-# ------------------------------------------------------------------------------
-# Add the executable.
-add_executable(initfscp ${SOURCE_FILES})
-
-

initscp/README.md

@@ -1,20 +0,0 @@
-----
-README
-initfscp - Autore di questa guida: Aleksej
-----
-
-initfscp e' un programma che serve a creare un'immagine contenente il file system utilizzato da MentOS.
-Consente di inserirci dei files e/o dei mountpoint (massimo 32) all'interno. 
-Per far ciò digitare il comando "initfscp [-m mountpoint1 -m mountpoint2 ... -m mountpoint n] file1 file2 ... nomefs" 
-
-dove:
-- -m mountpoint1 -m mountpoint2 ... -m mountpoint n (facoltativo) indicano i mountpoint da inserire nel filesystem appena creato. 
-- "file1 file2 ..." sono i files che inseriremo nel filesystem,
-- "nomefs" è il nome che daremo all'immagine.
-Ad esempio vogliamo inserire i file topolino, pippo e paperino nell'immagine che chiameremo disney, quindi digitiamo:
-  initfscp topolino pippo paperino disney
-così facendo initfscp genererà l'immagine disney.
-
-Altri comandi disponibili:
---help (-h) per visualizzare una guida più sintetica.
---version (-v) per visualizzare la versione utilizzata attualmente di initfscp.

initscp/inc/initfscp.h

@@ -1,42 +0,0 @@
-/// @file   initfscp.h
-/// @brief
-
-#pragma once
-
-#define MAX_FILENAME_LENGTH 64
-#define MAX_FILES 32
-#define INITFSCP_VER "0.3.0"
-
-#define FS_FILE 0x01 ///< Identifies a file.
-#define FS_DIRECTORY 0x02 ///< Identifies a directory.
-#define FS_CHARDEVICE 0x04 ///< Identifies a character devies.
-#define FS_BLOCKDEVICE 0x08 ///< Identifies a block devies.
-#define FS_PIPE 0x10 ///< Identifies a pipe.
-#define FS_SYMLINK 0x20 ///< Identifies a symbolic link.
-#define FS_MOUNTPOINT 0x40 ///< Identifies a mount-point.
-
-#define RESET "\033[00m"
-#define BLACK "\033[30m"
-#define RED "\033[31m"
-#define GREEN "\033[32m"
-#define YELLOW "\033[33m"
-#define BLUE "\033[34m"
-#define MAGENTA "\033[35m"
-#define CYAN "\033[36m"
-#define WHITE "\033[37m"
-
-/// @brief Information concerning a file.
-typedef struct initrd_file_t {
-	/// Number used as delimiter, it must be set to 0xBF.
-	int magic;
-	/// The name of the file.
-	char fileName[MAX_FILENAME_LENGTH];
-	/// The type of the file.
-	short int file_type;
-	/// The uid of the owner.
-	int uid;
-	/// Offset of the starting address.
-	unsigned int offset;
-	/// Dimension of the file.
-	unsigned int length;
-} initrd_file_t;

initscp/src/initfscp.c

@@ -1,324 +0,0 @@
-/// @file   initfscp.c
-/// @brief
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <initfscp.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <libgen.h>
-#include <dirent.h>
-#include <assert.h>
-
-static FILE *target_fs = NULL;
-static initrd_file_t headers[MAX_FILES];
-static char mount_points[MAX_FILES][MAX_FILENAME_LENGTH];
-static int mountpoint_idx = 0;
-static int header_idx = 0;
-static int header_offset = 0;
-
-static inline void usage(char *prgname)
-{
-	printf("Usage:\n");
-	printf(" %s --help        For this screen\n", prgname);
-	printf(" %s --source [-s] The source directory.\n", prgname);
-	printf(" %s --target [-t] The target file for the initfs.\n", prgname);
-}
-
-static inline void version(char *prgname)
-{
-	printf("%s version: %s\n", prgname, INITFSCP_VER);
-}
-
-static inline bool is_option_mount_point(char *arg)
-{
-	if (arg == NULL)
-		return false;
-	return ((strcmp(arg, "-m") == 0) || (strcmp(arg, "--mountpoint") == 0));
-}
-
-static inline bool is_option_source(char *arg)
-{
-	if (arg == NULL)
-		return false;
-	return ((strcmp(arg, "-s") == 0) || (strcmp(arg, "--source") == 0));
-}
-
-static inline bool is_option_target(char *arg)
-{
-	if (arg == NULL)
-		return false;
-	return ((strcmp(arg, "-t") == 0) || (strcmp(arg, "--target") == 0));
-}
-
-static inline bool is_mount_point(char *name)
-{
-	if (name == NULL)
-		return false;
-	// Check if the name matches with a mount-point.
-	for (int i = 0; i < mountpoint_idx; ++i) {
-		if (strcmp(name, mount_points[i]) == 0) {
-			return true;
-		}
-	}
-	return false;
-}
-
-static FILE *openfile(const char *dirname, struct dirent *dir, const char *mode)
-{
-	char pathname[1024];
-	FILE *fp;
-	sprintf(pathname, "%s/%s", dirname, dir->d_name);
-	fp = fopen(pathname, mode);
-	return fp;
-}
-
-static bool open_target_fs(int argc, char *argv[])
-{
-	printf("%-64s", "Opening target filesystem...");
-	for (int i = 1; i < argc; ++i) {
-		if (is_option_target(argv[i]) && ((i + 1) < argc)) {
-			target_fs = fopen(argv[i + 1], "w");
-			printf("[" GREEN "DONE" RESET "]\n\n");
-			return true;
-		}
-	}
-	printf("[" RED "FAILED" RESET "]\n\n");
-	return false;
-}
-
-static bool init_headers()
-{
-	printf("%-64s", "Initializing headers structures...");
-	for (size_t i = 0; i < MAX_FILES; i++) {
-		headers[i].magic = 0xBF;
-		memset(headers[i].fileName, 0, MAX_FILENAME_LENGTH);
-		headers[i].file_type = 0;
-		headers[i].uid = 0;
-		headers[i].offset = 0;
-		headers[i].length = 0;
-	}
-	printf("[" GREEN "DONE" RESET "]\n\n");
-	return true;
-}
-
-static bool init_mount_points(int argc, char *argv[])
-{
-	printf("Initializing mount points...\n");
-	for (int i = 1; i < argc; ++i) {
-		if (is_option_mount_point(argv[i]) && ((i + 1) < argc)) {
-			strcpy(mount_points[mountpoint_idx], argv[i + 1]);
-			printf("[%3d] MPNT: %-52s", mountpoint_idx,
-				   mount_points[mountpoint_idx]);
-			printf("[" CYAN "DONE" RESET "]\n");
-			++mountpoint_idx;
-		}
-	}
-	printf("[" GREEN "DONE" RESET "]\n\n");
-	return true;
-}
-
-static bool create_file_headers(char *mountpoint, char *directory)
-{
-	assert(mountpoint && "Received null mountpoint.");
-	assert(directory && "Received null directory.");
-
-	// ------------------------------------------------------------------------
-	char absolute_path[256];
-	memset(absolute_path, 0, 256);
-	strcpy(absolute_path, mountpoint);
-	strcat(absolute_path, directory);
-
-	// ------------------------------------------------------------------------
-	DIR *source_dir = opendir(absolute_path);
-	if (source_dir == NULL) {
-		printf("[" RED "FAILED" RESET "]\n");
-		printf("Could not open source directory %s.\n", absolute_path);
-		return false;
-	}
-	struct dirent *entry;
-	while ((entry = readdir(source_dir)) != NULL) {
-		if ((strcmp(entry->d_name, ".") == 0) ||
-			(strcmp(entry->d_name, "..") == 0)) {
-			continue;
-		}
-		if (entry->d_type != DT_DIR) {
-			char relative_filename[256];
-			strcpy(relative_filename, directory);
-			strcat(relative_filename, "/");
-			strcat(relative_filename, entry->d_name);
-
-			// ----------------------------------------------------------------
-			FILE *fd = openfile(absolute_path, entry, "r+");
-			printf("[%3d] FILE: %-52s", header_idx, relative_filename);
-			if (fd == NULL) {
-				printf("[" RED "FAILED" RESET "]\n");
-				printf("Error while opening file : %s\n", relative_filename);
-			}
-			fseek(fd, 0, SEEK_END);
-			long length = ftell(fd);
-			fclose(fd);
-
-			// ----------------------------------------------------------------
-			strcpy(headers[header_idx].fileName, relative_filename);
-			headers[header_idx].file_type = FS_FILE;
-			headers[header_idx].length = length;
-			headers[header_idx].offset = header_offset;
-
-			// ----------------------------------------------------------------
-			printf("[" BLUE "OPEN" RESET "]");
-			printf("[OFFSET:%6d]", headers[header_idx].offset);
-			printf("[SIZE:%6d]", headers[header_idx].length);
-			printf("[" GREEN "DONE" RESET "]\n");
-
-			header_offset += headers[header_idx].length;
-			++header_idx;
-		} else {
-			// ----------------------------------------------------------------
-			char sub_directory[256];
-			memset(sub_directory, 0, 256);
-			strcpy(sub_directory, directory);
-			strcat(sub_directory, "/");
-			strcat(sub_directory, entry->d_name);
-
-			// ----------------------------------------------------------------
-			strcpy(headers[header_idx].fileName, sub_directory);
-			headers[header_idx].file_type = FS_DIRECTORY;
-			headers[header_idx].length = 0;
-			headers[header_idx].offset = 0 /*++header_offset*/;
-
-			// ----------------------------------------------------------------
-			// Check if the directory is a mountpoint.
-			if (is_mount_point(headers[header_idx].fileName)) {
-				headers[header_idx].file_type = FS_MOUNTPOINT;
-			}
-
-			// ----------------------------------------------------------------
-			printf("[%3d] %3s : %-52s", header_idx,
-				   (headers[header_idx].file_type == FS_DIRECTORY) ? "DIR" :
-																	 "MPT",
-				   sub_directory);
-			printf("[" BLUE "OPEN" RESET "]");
-			printf("[OFFSET:%6d]", headers[header_idx].offset);
-			printf("[SIZE:%6d]", headers[header_idx].length);
-			printf("[" GREEN "DONE" RESET "]\n");
-
-			// ----------------------------------------------------------------
-			++header_idx;
-
-			// ----------------------------------------------------------------
-			create_file_headers(mountpoint, sub_directory);
-		}
-	}
-	closedir(source_dir);
-	return true;
-}
-
-static bool write_file_system(char *mountpoint)
-{
-	printf("Copying data to filesystem...\n");
-	for (int i = 0; i < MAX_FILES; i++) {
-		// --------------------------------------------------------------------
-		char absolute_path[256];
-		memset(absolute_path, 0, 256);
-		strcpy(absolute_path, mountpoint);
-		strcat(absolute_path, headers[i].fileName);
-
-		// --------------------------------------------------------------------
-		if (headers[i].file_type == FS_FILE) {
-			FILE *fd2 = fopen(absolute_path, "r+");
-			if (fd2 == NULL) {
-				continue;
-			}
-			printf("[%3d] FILE: %-92s", i, absolute_path);
-			char *buffer = (char *)malloc(headers[i].length);
-			fread(buffer, 1, headers[i].length, fd2);
-			fwrite(buffer, 1, headers[i].length, target_fs);
-			printf("[" GREEN "DONE" RESET "]\n");
-			fclose(fd2);
-			free(buffer);
-		}
-	}
-	printf("[" GREEN "DONE" RESET "]\n\n");
-	return true;
-}
-
-int main(int argc, char *argv[])
-{
-	printf("Welcome to MentOS initfs file copier tool\n\n");
-	if (argc <= 1) {
-		if (argv[0][0] == '.') {
-			version(argv[0] + 2);
-		}
-		usage(argv[0]);
-		return EXIT_FAILURE;
-	}
-	if (!strcmp(argv[1], "--version") || !strcmp(argv[1], "-v")) {
-		version(argv[0] + 2);
-		return EXIT_SUCCESS;
-	}
-	if (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")) {
-		usage(argv[0]);
-		return EXIT_SUCCESS;
-	}
-
-	// ------------------------------------------------------------------------
-	// Open the fs.
-	if (!open_target_fs(argc, argv)) {
-		printf("Could not open target FileSystem.\n");
-		return EXIT_FAILURE;
-	}
-
-	// ------------------------------------------------------------------------
-	// Initialize the headers.
-	if (!init_headers()) {
-		printf("Could not initialize headers.\n");
-		fclose(target_fs);
-		return EXIT_FAILURE;
-	}
-
-	// ------------------------------------------------------------------------
-	// Initialize the mountpoints.
-	if (!init_mount_points(argc, argv)) {
-		printf("Could not initialize mount points.\n");
-		fclose(target_fs);
-		return EXIT_FAILURE;
-	}
-
-	// ------------------------------------------------------------------------
-	// Create file headers.
-	header_offset = sizeof(struct initrd_file_t) * MAX_FILES + sizeof(int);
-	printf("Creating headers...\n");
-	for (uint32_t i = 1; i < argc; ++i) {
-		if (is_option_source(argv[i]) && ((i + 1) < argc)) {
-			if (!create_file_headers(argv[i + 1], "")) {
-				printf("Could not create file headers.\n");
-				fclose(target_fs);
-				return EXIT_FAILURE;
-			}
-		}
-	}
-	printf("[" GREEN "DONE" RESET "]\n\n");
-
-	// ------------------------------------------------------------------------
-	// Copying information about headers on filesystem.
-	printf("%-64s", "Copying information about headers to filesystem...");
-	fwrite(&header_idx, sizeof(int), 1, target_fs);
-	fwrite(headers, sizeof(struct initrd_file_t), 32, target_fs);
-	printf("[" GREEN "DONE" RESET "]\n\n");
-
-	// ------------------------------------------------------------------------
-	// Write headers on filesystem.
-	for (uint32_t i = 1; i < argc; ++i) {
-		if (is_option_source(argv[i]) && ((i + 1) < argc)) {
-			if (!write_file_system(argv[i + 1])) {
-				printf("Could not write on filesystem.\n");
-				fclose(target_fs);
-				return EXIT_FAILURE;
-			}
-		}
-	}
-	fclose(target_fs);
-	return 0;
-}

iso/boot/grub/grub.cfg

@@ -0,0 +1,7 @@
+set timeout=1
+set default=0
+
+menuentry "MentOS" {
+     multiboot /boot/kernel-bootloader.bin
+     boot
+}

libc/CMakeLists.txt

@@ -0,0 +1,148 @@
+# =============================================================================
+# Author: Enrico Fraccaroli
+# =============================================================================
+# Set the minimum required version of cmake.
+cmake_minimum_required(VERSION 3.1...3.22)
+# Initialize the project.
+project(libc C ASM)
+
+# =============================================================================
+# ASSEMBLY
+# =============================================================================
+
+# Enable the assembly language.
+enable_language(ASM)
+# Find the NASM compiler.
+find_program(ASM_COMPILER NAMES nasm HINTS /usr/bin/ /usr/local/bin/)
+# Mark the variable ASM_COMPILER as advanced.
+mark_as_advanced(ASM_COMPILER)
+# Check that we have found the compiler.
+if(NOT ASM_COMPILER)
+    message(FATAL_ERROR "ASM compiler not found!")
+endif(NOT ASM_COMPILER)
+# Set the asm compiler.
+set(CMAKE_ASM_COMPILER ${ASM_COMPILER})
+# Set the assembly compiler flags.
+set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -f elf")
+set(CMAKE_ASM_COMPILE_OBJECT "<CMAKE_ASM_COMPILER> <FLAGS> -o <OBJECT> <SOURCE>")
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -g")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -O0")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -F dwarf")
+elseif(CMAKE_BUILD_TYPE STREQUAL "Release")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -g")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -O3")
+endif(CMAKE_BUILD_TYPE STREQUAL "Debug")
+
+# =============================================================================
+# C WARNINGs
+# =============================================================================
+
+# Warning flags.
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wpedantic")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pedantic-errors")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wshadow")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
+
+# Disable some specific warnings.
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-function")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-variable")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unknown-pragmas")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-missing-braces")
+
+# Set the compiler options.
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -static")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -nostdlib")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -nostdinc")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-builtin")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-stack-protector")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-pic")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fomit-frame-pointer")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -m32")
+if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10)
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fcommon")
+endif()
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=i686")
+
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g3")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ggdb")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0")
+elseif(CMAKE_BUILD_TYPE STREQUAL "Release")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
+endif(CMAKE_BUILD_TYPE STREQUAL "Debug")
+
+# =============================================================================
+# Add the library.
+add_library(
+    ${PROJECT_NAME}
+
+    ${PROJECT_SOURCE_DIR}/src/stdio.c
+    ${PROJECT_SOURCE_DIR}/src/ctype.c
+    ${PROJECT_SOURCE_DIR}/src/string.c
+    ${PROJECT_SOURCE_DIR}/src/stdlib.c
+    ${PROJECT_SOURCE_DIR}/src/math.c
+    ${PROJECT_SOURCE_DIR}/src/fcvt.c
+    ${PROJECT_SOURCE_DIR}/src/time.c
+    ${PROJECT_SOURCE_DIR}/src/strerror.c
+    ${PROJECT_SOURCE_DIR}/src/termios.c
+    ${PROJECT_SOURCE_DIR}/src/libgen.c
+    ${PROJECT_SOURCE_DIR}/src/vsprintf.c
+    ${PROJECT_SOURCE_DIR}/src/vscanf.c
+    ${PROJECT_SOURCE_DIR}/src/pwd.c
+    ${PROJECT_SOURCE_DIR}/src/grp.c
+    ${PROJECT_SOURCE_DIR}/src/sched.c
+    ${PROJECT_SOURCE_DIR}/src/setenv.c
+    ${PROJECT_SOURCE_DIR}/src/assert.c
+    ${PROJECT_SOURCE_DIR}/src/abort.c
+    ${PROJECT_SOURCE_DIR}/src/io/mm_io.c
+    ${PROJECT_SOURCE_DIR}/src/io/port_io.c
+    ${PROJECT_SOURCE_DIR}/src/ipc/ipc.c
+    ${PROJECT_SOURCE_DIR}/src/sys/unistd.c
+    ${PROJECT_SOURCE_DIR}/src/sys/errno.c
+    ${PROJECT_SOURCE_DIR}/src/sys/utsname.c
+    ${PROJECT_SOURCE_DIR}/src/sys/ioctl.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/creat.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getppid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getpid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/exit.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/setsid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getsid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/setpgid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getpgid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/setgid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getgid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/setuid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getuid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/fork.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/read.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/write.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/exec.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/nice.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/open.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/reboot.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/waitpid.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/chdir.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getcwd.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/close.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/stat.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/rmdir.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/mkdir.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/unlink.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/getdents.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/lseek.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/kill.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/signal.c
+    ${PROJECT_SOURCE_DIR}/src/unistd/interval.c
+    ${PROJECT_SOURCE_DIR}/src/libc_start.c
+    ${PROJECT_SOURCE_DIR}/src/debug.c
+    ${PROJECT_SOURCE_DIR}/src/crt0.S
+)
+
+# Add the includes.
+target_include_directories(${PROJECT_NAME} PUBLIC inc)
+
+# Remove the 'lib' prefix.
+set_target_properties(${PROJECT_NAME} PROPERTIES PREFIX "")

libc/inc/array.h

@@ -0,0 +1,38 @@
+/// @file array.h
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#ifdef __KERNEL__
+/// Function for allocating memory for the array.
+#define ARRAY_ALLOC kmalloc
+/// Function for freeing the memory for the array.
+#define ARRAY_FREE  kfree
+#else
+/// Function for allocating memory for the array.
+#define ARRAY_ALLOC malloc
+/// Function for freeing the memory for the array.
+#define ARRAY_FREE  free
+#endif
+
+/// @brief Declares a new dynamic-size array structure.
+#define DECLARE_ARRAY(type, name)                                                     \
+    typedef struct arr_##name##_t {                                                   \
+        const unsigned size;                                                          \
+        type *buffer;                                                                 \
+    } arr_##name##_t;                                                                 \
+    arr_##name##_t alloc_arr_##name(unsigned len)                                     \
+    {                                                                                 \
+        arr_##name##_t a = { len, len > 0 ? ARRAY_ALLOC(sizeof(type) * len) : NULL }; \
+        memset(a.buffer, 0, sizeof(type) * len);                                      \
+        return a;                                                                     \
+    }                                                                                 \
+    static inline void free_arr_##name(arr_##name##_t *arr)                           \
+    {                                                                                 \
+        ARRAY_FREE(arr->buffer);                                                      \
+    }
+
+#undef ARRAY_ALLOC malloc
+#undef ARRAY_FREE free

libc/inc/assert.h

@@ -0,0 +1,19 @@
+/// @file assert.h
+/// @brief Defines the function and pre-processor macro for assertions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief           Function used to log the information of a failed assertion.
+/// @param assertion The failed assertion.
+/// @param file      The file where the assertion is located.
+/// @param function  The function where the assertion is.
+/// @param line      The line inside the file.
+void __assert_fail(const char *assertion, const char *file, const char *function, unsigned int line);
+
+/// @brief Extract the filename from the full path provided by __FILE__.
+#define __FILENAME__ (__builtin_strrchr(__FILE__, '/') ? __builtin_strrchr(__FILE__, '/') + 1 : __FILE__)
+
+/// @brief Assert function.
+#define assert(expression) ((expression) ? (void)0 : __assert_fail(#expression, __FILENAME__, __func__, __LINE__))

libc/inc/bits/ioctls.h

@@ -0,0 +1,9 @@
+/// @file ioctls.h
+/// @brief Input/Output ConTroL (IOCTL) numbers.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#define TCGETS 0x5401U ///< Get the current serial port settings.
+#define TCSETS 0x5402U ///< Set the current serial port settings.

libc/inc/bits/stat.h

@@ -0,0 +1,35 @@
+/// @file stat.h
+/// @brief Defines the structure used by the functiosn fstat(), lstat(), and stat().
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#if !defined(__SYS_STAT_H) && !defined(__KERNEL__)
+#error "Never include <bits/stat.h> directly; use <sys/stat.h> instead."
+#endif
+
+#include "stddef.h"
+#include "time.h"
+
+/// @brief Data structure which contains information about a file.
+typedef struct stat_t {
+    /// ID of device containing file.
+    dev_t st_dev;
+    /// File serial number.
+    ino_t st_ino;
+    /// Mode of file.
+    mode_t st_mode;
+    /// File user id.
+    uid_t st_uid;
+    /// File group id.
+    gid_t st_gid;
+    /// File Size.
+    off_t st_size;
+    /// Time of last access.
+    time_t st_atime;
+    /// Time of last data modification.
+    time_t st_mtime;
+    /// Time of last status change.
+    time_t st_ctime;
+} stat_t;

libc/inc/bits/termios-struct.h

@@ -0,0 +1,46 @@
+/// @file termios-struct.h
+/// @brief Definition of the `termios` structure.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// Type for control characters.
+typedef unsigned char cc_t;
+/// Type for speed.
+typedef unsigned int speed_t;
+/// Type for flags.
+typedef unsigned int tcflag_t;
+/// The number of control characters.
+#define NCCS 32
+
+/// @brief Stores information about a terminal IOs.
+typedef struct termios {
+    tcflag_t c_iflag; ///< input mode flags
+    tcflag_t c_oflag; ///< output mode flags
+    tcflag_t c_cflag; ///< control mode flags
+    tcflag_t c_lflag; ///< local mode flags
+    cc_t c_line;      ///< line discipline
+    cc_t c_cc[NCCS];  ///< control characters
+    speed_t c_ispeed; ///< input speed
+    speed_t c_ospeed; ///< output speed
+} termios_t;
+
+//These flags generally control higher-level aspects of input processing than
+// the input modes flags described in Input Modes, such as echoing, signals, and
+// the choice of canonical or noncanonical input.
+
+#define ISIG    0x00000080 ///< Controls whether the INTR, QUIT, and SUSP characters are recognized.
+#define ICANON  0x00000100 ///< Enables canonical input processing mode.
+#define ECHO    0x00000008 ///< Echo input characters.
+#define ECHOE   0x00000002 ///< If ICANON is set, the ERASE character erases the preceding character.
+#define ECHOK   0x00000004 ///< If ICANON is set, the KILL character erases the current line.
+#define ECHONL  0x00000010 ///< If ICANON is set, echo the NL character even if ECHO is not set.
+#define NOFLSH  0x80000000 ///< Do not clear in/out queues when receiving INTR, QUIT, and SUSP.
+#define TOSTOP  0x00400000 ///< Allows SIGTTOU signals generated by background processes.
+#define ECHOCTL 0x00000040 ///< If this and ECHO are set, control characters with ‘^’ are echoed.
+#define ECHOKE  0x00000001 ///< If ICANON is set, KILL is echoed by erasing each character on the line.
+#define IEXTEN  0x00000400 ///< Enables implementation-defined input processing.
+
+/// @brief Mask for extracting control values.
+#define CTRL(x) (x & 037)

libc/inc/ctype.h

@@ -0,0 +1,56 @@
+/// @file ctype.h
+/// @brief Functions related to character handling.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Check if the given value is a digit.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isdigit(int c);
+
+/// @brief Check if the given value is a letter.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isalpha(int c);
+
+/// @brief Check if the given value is a control character.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int iscntrl(int c);
+
+/// @brief Check if the given value is either a letter or a digit.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isalnum(int c);
+
+/// @brief Check if the given value is an hexadecimal digit.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isxdigit(int c);
+
+/// @brief Check if the given value is a lower case letter.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int islower(int c);
+
+/// @brief Check if the given value is an upper case letter.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isupper(int c);
+
+/// @brief Transforms the given value into a lower case letter.
+/// @param c The input letter.
+/// @return The input letter turned into a lower case letter.
+int tolower(int c);
+
+/// @brief Transforms the given value into an upper case letter.
+/// @param c The input letter.
+/// @return The input letter turned into an upper case letter.
+int toupper(int c);
+
+/// @brief Check if the given value is a whitespace.
+/// @param c The input character.
+/// @return 1 on success, 0 otherwise.
+int isspace(int c);

libc/inc/debug.h

@@ -0,0 +1,44 @@
+/// @file debug.h
+/// @brief Debugging primitives.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#ifndef __DEBUG_HEADER__
+/// Header for identifying outputs coming from a mechanism.
+#define __DEBUG_HEADER__
+#endif
+
+/// @brief Extract the filename from the full path provided by __FILE__.
+#define __FILENAME__ (__builtin_strrchr(__FILE__, '/') ? __builtin_strrchr(__FILE__, '/') + 1 : __FILE__)
+
+/// @brief Prints the given character to debug output.
+/// @param c The character to print.
+void dbg_putchar(char c);
+
+/// @brief Prints the given string to debug output.
+/// @param s The string to print.
+void dbg_puts(const char *s);
+
+/// @brief Prints the given string to the debug output.
+/// @param file   The name of the file.
+/// @param fun    The name of the function.
+/// @param line   The line inside the file.
+/// @param format The format to used, see printf.
+/// @param ...    The list of arguments.
+void dbg_printf(const char *file, const char *fun, int line, const char *format, ...);
+
+/// @brief Transforms the given amount of bytes to a readable string.
+/// @param bytes The bytes to turn to string.
+/// @return String representing the bytes in human readable form.
+const char *to_human_size(unsigned long bytes);
+
+/// @brief Transforms the given value to a binary string.
+/// @param value to print.
+/// @param length of the binary output.
+/// @return String representing the binary value.
+const char *dec_to_binary(unsigned long value, unsigned length);
+
+/// Prints a debugging message.
+#define pr_debug(...) dbg_printf(__FILENAME__, __func__, __LINE__, __DEBUG_HEADER__ __VA_ARGS__)

libc/inc/fcntl.h

@@ -0,0 +1,46 @@
+/// @file fcntl.h
+/// @brief Headers of functions fcntl() and open().
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#define O_RDONLY    00000000U ///< Open for reading only.
+#define O_WRONLY    00000001U ///< Open for writing only.
+#define O_RDWR      00000002U ///< Open for reading and writing.
+#define O_CREAT     00000100U ///< Create if nonexistant.
+#define O_EXCL      00000200U ///< Error if already exists.
+#define O_TRUNC     00001000U ///< Truncate to zero length.
+#define O_APPEND    00002000U ///< Set append mode.
+#define O_NONBLOCK  00004000U ///< No delay.
+#define O_DIRECTORY 00200000U ///< If file exists has no effect. Otherwise, the file is created.
+
+/// @defgroup ModeBitsAccessPermission Mode Bits for Access Permission
+/// @brief The file modes.
+/// @{
+
+#define S_ISUID 0x0800 ///< Set user id on execution
+#define S_ISGID 0x0400 ///< Set group id on execution
+#define S_ISVTX 0x0200 ///< Save swapped text even after use (Sticky Bit)
+#define S_IRWXU 0x01C0 ///< rwx------- : User can read/write/execute
+#define S_IRUSR 0x0100 ///< -r-------- : User can read
+#define S_IWUSR 0x0080 ///< --w------- : User can write
+#define S_IXUSR 0x0040 ///< ---x------ : User can execute
+#define S_IRWXG 0x0038 ///< ----rwx--- : Group can read/write/execute
+#define S_IRGRP 0x0020 ///< ----r----- : Group can read
+#define S_IWGRP 0x0010 ///< -----w---- : Group can write
+#define S_IXGRP 0x0008 ///< ------x--- : Group can execute
+#define S_IRWXO 0x0007 ///< -------rwx : Others can read/write/execute
+#define S_IROTH 0x0004 ///< -------r-- : Others can read
+#define S_IWOTH 0x0002 ///< --------w- : Others can write
+#define S_IXOTH 0x0001 ///< ---------x : Others can execute
+
+#define S_ISDIR(m)  (((m)&0170000) == 0040000) ///< directory.
+#define S_ISCHR(m)  (((m)&0170000) == 0020000) ///< char special
+#define S_ISBLK(m)  (((m)&0170000) == 0060000) ///< block special
+#define S_ISREG(m)  (((m)&0170000) == 0100000) ///< regular file
+#define S_ISFIFO(m) (((m)&0170000) == 0010000) ///< fifo
+#define S_ISLNK(m)  (((m)&0170000) == 0120000) ///< symbolic link
+#define S_ISSOCK(m) (((m)&0170000) == 0140000) ///< socket
+
+/// @}

libc/inc/fcvt.h

@@ -0,0 +1,36 @@
+/// @file fcvt.h
+/// @brief Declare the functions required to turn double values into a string.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Thif function transforms `value` into a string of digits inside `buf`,
+///         representing the whole part followed by the decimal part.
+/// @details
+/// For instance, 512.765 will result in:
+///     decpt = 3
+///     sign  = 0
+///     buf   = "512765"
+/// @param arg      The argument to turn into string.
+/// @param chars    The total number of digits.
+/// @param decpt    The position of the decimal point.
+/// @param sign     The sign of the number.
+/// @param buf      Buffer where the digits should be placed.
+/// @param buf_size Dimension of the buffer.
+void ecvtbuf(double arg, int chars, int *decpt, int *sign, char *buf, unsigned buf_size);
+
+/// @brief Thif function transforms `value` into a string of digits inside `buf`,
+///         representing the whole part followed by the decimal part.
+/// @details
+/// For instance, 512.765 will result in:
+///     decpt = 3
+///     sign  = 0
+///     buf   = "512765"
+/// @param arg      The argument to turn into string.
+/// @param decimals The total number of digits to write after the decimal point.
+/// @param decpt    The position of the decimal point.
+/// @param sign     The sign of the number.
+/// @param buf      Buffer where the digits should be placed.
+/// @param buf_size Dimension of the buffer.
+void fcvtbuf(double arg, int decimals, int *decpt, int *sign, char *buf, unsigned buf_size);

libc/inc/grp.h

@@ -0,0 +1,72 @@
+/// @file grp.h
+/// @brief Defines the structures and functions for managing groups.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// Maximum number of users per group
+#define MAX_MEMBERS_PER_GROUP 64
+
+/// @brief Contains user group informations.
+typedef struct group {
+    /// The name of the group.
+    char *gr_name;
+    /// Encrypted password.
+    char *gr_passwd;
+    /// Group ID.
+    gid_t gr_gid;
+    /// List of group members.
+    char *gr_mem[MAX_MEMBERS_PER_GROUP + 1];
+} group_t;
+
+/// @brief Provides access to the group database entry for `uid`.
+/// @param gid The gid to search inside the database.
+/// @return A pointer to the structure containing the database entry.
+group_t *getgrgid(gid_t gid);
+
+/// @brief Provides access to the group database entry for `name`.
+/// @param name The name to search inside the database.
+/// @return A pointer to the structure containing the database entry.
+group_t *getgrnam(const char *name);
+
+/// @brief Provides the same information as getgrgid but it stores the results
+/// inside group, and the string information are store store inside `buf`.
+/// @param gid The uid to search inside the database.
+/// @param group The structure containing pointers to the entry fields.
+/// @param buf The buffer where the strings should be stored.
+/// @param buflen The lenght of the buffer.
+/// @param result A pointer to the result or NULL is stored here.
+/// @return If the entry was found returns zero and set *result to group, if the
+/// entry was not found returns zero and set *result to NULL, on failure returns
+/// a number and sets  and set *result to NULL.
+int getgrgid_r(gid_t gid, group_t *group, char *buf, size_t buflen, group_t **result);
+
+/// @brief Provides the same information as getgrnam but it stores the results
+///inside group, and the string information are store store inside `buf`.
+/// @param name The name to search inside the database.
+/// @param group The structure containing pointers to the entry fields.
+/// @param buf The buffer where the strings should be stored.
+/// @param buflen The lenght of the buffer.
+/// @param result A pointer to the result or NULL is stored here.
+/// @return If the entry was found returns zero and set *result to group, if the
+/// entry was not found returns zero and set *result to NULL, on failure returns
+/// a number and sets  and set *result to NULL.
+int getgrnam_r(const char *name, group_t *group, char *buf, size_t buflen, group_t **result);
+
+/// @brief Returns a pointer to a structure containing the broken-out fields of
+/// an entry in the group database.
+/// @return pointer to the group entry.
+/// @details When first called returns a pointer to a group structure containing
+/// the first entry in the group database. Thereafter, it returns a pointer to a
+/// group structure containing the next group structure in the group database,
+/// so successive calls may be used to search the entire database.
+group_t *getgrent(void);
+
+/// @brief Rewinds the group database to allow repeated searches.
+void endgrent(void);
+
+/// @brief May be called to close the group database when processing is complete.
+void setgrent(void);

libc/inc/io/mm_io.h

@@ -0,0 +1,26 @@
+/// @file mm_io.h
+/// @brief Memory Mapped IO functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stdint.h"
+
+/// @brief Reads a 8-bit value from the given address.
+uint8_t in_memb(uint32_t addr);
+
+/// @brief Reads a 16-bit value from the given address.
+uint16_t in_mems(uint32_t addr);
+
+/// @brief Reads a 32-bit value from the given address.
+uint32_t in_meml(uint32_t addr);
+
+/// @brief Writes a 8-bit value at the given address.
+void out_memb(uint32_t addr, uint8_t value);
+
+/// @brief Writes a 16-bit value at the given address.
+void out_mems(uint32_t addr, uint16_t value);
+
+/// @brief Writes a 32-bit value at the given address.
+void out_meml(uint32_t addr, uint32_t value);

libc/inc/io/port_io.h

@@ -0,0 +1,42 @@
+/// @file port_io.h
+/// @brief Byte I/O on ports prototypes.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stdint.h"
+
+/// @brief      Used for reading from the I/O ports.
+/// @param port The input port.
+/// @return     The read value.
+uint8_t inportb(uint16_t port);
+
+/// @brief      Used for reading 2 bytes from the I/O ports.
+/// @param port The input port.
+/// @return     The read value.
+uint16_t inports(uint16_t port);
+
+void inportsm(uint16_t port, uint8_t *data, unsigned long size);
+
+/// @brief      Used for reading 4 bytes from the I/O ports.
+/// @param port The input port.
+/// @return     The read value.
+uint32_t inportl(uint16_t port);
+
+/// @brief      Use this to write to I/O ports to send bytes to devices.
+/// @param port The output port.
+/// @param data The data to write.
+void outportb(uint16_t port, uint8_t data);
+
+/// @brief      Use this to write to I/O ports to send 2 bytes to devices.
+/// @param port The output port.
+/// @param data The data to write.
+void outports(uint16_t port, uint16_t data);
+
+void outportsm(uint16_t port, uint8_t *data, uint16_t size);
+
+/// @brief      Use this to write to I/O ports to send 4 bytes to devices.
+/// @param port The output port.
+/// @param data The data to write.
+void outportl(uint16_t port, uint32_t data);

libc/inc/ipc/ipc.h

@@ -0,0 +1,24 @@
+/// @file ipc.h
+/// @brief Inter-Process Communication (IPC) structures.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Permission details of an IPC object.
+struct ipc_perm {
+    /// Key supplied to msgget(2).
+    key_t __key;
+    /// Effective UID of owner.
+    uid_t uid;
+    /// Effective GID of owner.
+    gid_t gid;
+    /// Effective UID of creator.
+    uid_t cuid;
+    /// Effective GID of creator.
+    gid_t cgid;
+    /// Permissions.
+    unsigned short mode;
+    /// Sequence number.
+    unsigned short __seq;
+};

libc/inc/ipc/msg.h

@@ -0,0 +1,125 @@
+/// @file msg.h
+/// @brief Definition of structure for managing message queues.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "sys/types.h"
+#include "stddef.h"
+#include "time.h"
+#include "ipc.h"
+
+/// Type for storing the number of messages in a message queue.
+typedef unsigned int msgqnum_t;
+
+/// Type for storing the number of bytes in a message queue.
+typedef unsigned int msglen_t;
+
+/// @brief Buffer to use with the message queue IPC.
+typedef struct msgbuf {
+    /// Type of the message.
+    long mtype;
+    /// Text of the message.
+    char mtext[1];
+} msgbuf_t;
+
+/// @brief Message queue data structure.
+typedef struct msqid_ds {
+    /// Ownership and permissions.
+    struct ipc_perm msg_perm;
+    /// Time of last msgsnd(2).
+    time_t msg_stime;
+    /// Time of last msgrcv(2).
+    time_t msg_rtime;
+    /// Time of creation or last modification by msgctl().
+    time_t msg_ctime;
+    /// Number of bytes in queue.
+    unsigned long msg_cbytes;
+    /// Number of messages in queue.
+    msgqnum_t msg_qnum;
+    /// Maximum number of bytes in queue.
+    msglen_t msg_qbytes;
+    /// PID of last msgsnd(2).
+    pid_t msg_lspid;
+    /// PID of last msgrcv(2).
+    pid_t msg_lrpid;
+} msqid_ds_t;
+
+#ifdef __KERNEL__
+
+/// @brief Get a System V message queue identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created message queue, or to create a new set.
+/// @param msgflg controls the behaviour of the function.
+/// @return the message queue identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long sys_msgget(key_t key, int msgflg);
+
+/// @brief Used to send messages.
+/// @param msqid the message queue identifier.
+/// @param msgp points to a used-defined msgbuf.
+/// @param msgsz specifies the size in bytes of mtext.
+/// @param msgflg specifies the action to be taken in case of specific events.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_msgsnd(int msqid, msgbuf_t *msgp, size_t msgsz, int msgflg);
+
+/// @brief Used to receive messages.
+/// @param msqid the message queue identifier.
+/// @param msgp points to a used-defined msgbuf.
+/// @param msgsz specifies the size in bytes of mtext.
+/// @param msgtyp specifies the type of message requested, as follows:
+/// - msgtyp == 0: the first message on the queue is received.
+/// - msgtyp  > 0: the first message of type, msgtyp, is received.
+/// - msgtyp  < 0: the first message of the lowest type that is less than or
+///                equal to the absolute value of msgtyp is received.
+/// @param msgflg specifies the action to be taken in case of specific events.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_msgrcv(int msqid, msgbuf_t *msgp, size_t msgsz, long msgtyp, int msgflg);
+
+/// @brief Message queue control operations.
+/// @param msqid the message queue identifier.
+/// @param cmd The command to perform.
+/// @param buf used with IPC_STAT and IPC_SET.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_msgctl(int msqid, int cmd, msqid_ds_t *buf);
+
+#else
+
+/// @brief Get a System V message queue identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created message queue, or to create a new set.
+/// @param msgflg controls the behaviour of the function.
+/// @return the message queue identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long msgget(key_t key, int msgflg);
+
+/// @brief Used to send messages.
+/// @param msqid the message queue identifier.
+/// @param msgp points to a used-defined msgbuf.
+/// @param msgsz specifies the size in bytes of mtext.
+/// @param msgflg specifies the action to be taken in case of specific events.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long msgsnd(int msqid, msgbuf_t *msgp, size_t msgsz, int msgflg);
+
+/// @brief Used to receive messages.
+/// @param msqid the message queue identifier.
+/// @param msgp points to a used-defined msgbuf.
+/// @param msgsz specifies the size in bytes of mtext.
+/// @param msgtyp specifies the type of message requested, as follows:
+/// - msgtyp == 0: the first message on the queue is received.
+/// - msgtyp  > 0: the first message of type, msgtyp, is received.
+/// - msgtyp  < 0: the first message of the lowest type that is less than or
+///                equal to the absolute value of msgtyp is received.
+/// @param msgflg specifies the action to be taken in case of specific events.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long msgrcv(int msqid, msgbuf_t *msgp, size_t msgsz, long msgtyp, int msgflg);
+
+/// @brief Message queue control operations.
+/// @param msqid the message queue identifier.
+/// @param cmd The command to perform.
+/// @param buf used with IPC_STAT and IPC_SET.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long msgctl(int msqid, int cmd, msqid_ds_t *buf);
+
+#endif

libc/inc/ipc/sem.h

@@ -0,0 +1,75 @@
+/// @file sem.h
+/// @brief Definition of structure for managing semaphores.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "sys/types.h"
+#include "stddef.h"
+#include "time.h"
+#include "ipc.h"
+
+/// @brief Buffer to use with the semaphore IPC.
+struct sembuf {
+    /// Semaphore index in array.
+    unsigned short sem_num;
+    /// Semaphore operation.
+    short sem_op;
+    /// Operation flags.
+    short sem_flg;
+};
+
+#ifdef __KERNEL__
+
+/// @brief Get a System V semaphore set identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created semaphore set, or to create a new set.
+/// @param nsems number of semaphores.
+/// @param semflg controls the behaviour of the function.
+/// @return the semaphore set identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long sys_semget(key_t key, int nsems, int semflg);
+
+/// @brief Performs operations on selected semaphores in the set.
+/// @param semid the semaphore set identifier.
+/// @param sops specifies operations to be performed on single semaphores.
+/// @param nsops number of operations.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_semop(int semid, struct sembuf *sops, unsigned nsops);
+
+/// @brief Performs control operations on a semaphore set.
+/// @param semid the semaphore set identifier.
+/// @param semnum the n-th semaphore of the set on which we perform the operations.
+/// @param cmd the command to perform.
+/// @param arg
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_semctl(int semid, int semnum, int cmd, unsigned long arg);
+
+#else
+
+/// @brief Get a System V semaphore set identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created semaphore set, or to create a new set.
+/// @param nsems number of semaphores.
+/// @param semflg controls the behaviour of the function.
+/// @return the semaphore set identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long semget(key_t key, int nsems, int semflg);
+
+/// @brief Performs operations on selected semaphores in the set.
+/// @param semid the semaphore set identifier.
+/// @param sops specifies operations to be performed on single semaphores.
+/// @param nsops number of operations.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long semop(int semid, struct sembuf *sops, unsigned nsops);
+
+/// @brief Performs control operations on a semaphore set.
+/// @param semid the semaphore set identifier.
+/// @param semnum the n-th semaphore of the set on which we perform the operations.
+/// @param cmd the command to perform.
+/// @param arg
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long semctl(int semid, int semnum, int cmd, unsigned long arg);
+
+#endif

libc/inc/ipc/shm.h

@@ -0,0 +1,206 @@
+/// @file shm.h
+/// @brief Definition of structure for managing shared memories.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "sys/types.h"
+#include "stddef.h"
+#include "time.h"
+#include "ipc.h"
+
+/// Data type for storing the number of attaches.
+typedef unsigned long shmatt_t;
+
+/// @brief Shared memory data structure.
+struct shmid_ds {
+    /// Operation permission struct.
+    struct ipc_perm shm_perm;
+    /// Size of segment in bytes.
+    size_t shm_segsz;
+    /// Time of last shmat().
+    time_t shm_atime;
+    /// Time of last shmdt().
+    time_t shm_dtime;
+    /// Time of last change by shmctl().
+    time_t shm_ctime;
+    /// Pid of creator.
+    pid_t shm_cpid;
+    /// Pid of last shmop.
+    pid_t shm_lpid;
+    /// Number of current attaches.
+    shmatt_t shm_nattch;
+    /// Pointer to the next shared memory data structure.
+    struct shmid_ds *next;
+    /// Where shm created is memorized, should be a file.
+    void *shm_location;
+};
+
+#if 0
+
+#include "ipc.h"
+#include "debug.h"
+#include "time.h"
+#include "kheap.h"
+#include "stddef.h"
+#include "paging.h"
+#include "syscall.h"
+#include "scheduler.h"
+
+//======== Permission flag for shmget ==========================================
+// or S_IRUGO from <linux/stat.h>.
+#define SHM_R      0400
+
+// or S_IWUGO from <linux/stat.h>.
+#define SHM_W      0200
+//==============================================================================
+
+//======== Flags for shmat =====================================================
+// Attach read-only else read-write.
+#define SHM_RDONLY 010000
+
+// Round attach address to SHMLBA.
+#define SHM_RND    020000
+
+// Take-over region on attach.
+#define SHM_REMAP  040000
+
+// Execution access.
+#define SHM_EXEC   0100000
+//==============================================================================
+
+//======== Commands for shmctl =================================================
+// Lock segment (root only).
+#define SHM_LOCK   11
+
+// Unlock segment (root only).
+#define SHM_UNLOCK 12
+//==============================================================================
+
+// Ipcs ctl commands.
+#define SHM_STAT   13
+
+#define SHM_INFO 14
+
+#define SHM_STAT_ANY  15
+
+//======== shm_mode upper byte flags ===========================================
+// segment will be destroyed on last detach.
+#define SHM_DEST      01000
+
+// Segment will not be swapped.
+#define SHM_LOCKED    02000
+
+// Segment is mapped via hugetlb.
+#define SHM_HUGETLB   04000
+
+// Don't check for reservations.
+#define SHM_NORESERVE 010000
+
+/// @@brief Syscall Service Routine: Shared memory control operation.
+int syscall_shmctl(int *args);
+
+/// @@brief Syscall Service Routine: Get shared memory segment.
+int syscall_shmget(int *args);
+
+/// @@brief Syscall Service Routine: Attach shared memory segment.
+void *syscall_shmat(int *args);
+
+/// @@brief Syscall  Service Routine: Detach shared memory segment.
+int syscall_shmdt(int *args);
+
+/// @@brief User Wrapper: Shared memory control operation.
+int shmctl(int shmid, int cmd, struct shmid_ds *buf);
+
+/// @@brief User Wrapper: Get shared memory segment.
+int shmget(key_t key, size_t size, int flags);
+
+/// @@brief User Wrapper: Attach shared memory segment.
+void *shmat(int shmid, void *shmaddr, int flag);
+
+/// @@brief User Wrapper: Detach shared memory segment.
+int shmdt(void *shmaddr);
+
+/// @@brief Find shmid_ds on list.
+struct shmid_ds *find_shm_fromid(int shmid);
+
+/// @@brief Find shmid_ds on list.
+struct shmid_ds *find_shm_fromkey(key_t key);
+
+/// @@brief shmid_ds on list.
+struct shmid_ds *find_shm_fromvaddr(void *shmvaddr);
+
+#endif
+
+#ifdef __KERNEL__
+
+/// @brief Get a System V shared memory identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created shared memory, or to create a new one.
+/// @param size of the shared memory, rounded up to a multiple of PAGE_SIZE.
+/// @param flag controls the behaviour of the function.
+/// @return the shared memory identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long sys_shmget(key_t key, size_t size, int flag);
+
+/// @brief Attaches the shared memory segment identified by shmid to the address
+/// space of the calling process.
+/// @param shmid the shared memory identifier.
+/// @param shmaddr the attaching address.
+/// @param shmflg controls the behaviour of the function.
+/// @return returns the address of the attached shared memory segment; on error
+/// (void *) -1 is returned, and errno is set to indicate the error.
+void * sys_shmat(int shmid, const void *shmaddr, int shmflg);
+
+/// @brief Detaches the shared memory segment located at the address specified
+/// by shmaddr from the address space of the calling process
+/// @param shmaddr the address of the shared memory segment.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long sys_shmdt(const void *shmaddr);
+
+/// @brief Performs the control operation specified by cmd on the shared memory
+/// segment whose identifier is given in shmid.
+/// @param shmid the shared memory identifier.
+/// @param cmd the command to perform.
+/// @param buf is a pointer to a shmid_ds structure.
+/// @return a non-negative value basedon on the requested operation, -1 on
+/// failure and errno is set to indicate the error.
+long sys_shmctl(int shmid, int cmd, struct shmid_ds *buf);
+
+#else
+
+/// @brief Get a System V shared memory identifier.
+/// @param key can be used either to obtain the identifier of a previously
+/// created shared memory, or to create a new one.
+/// @param size of the shared memory, rounded up to a multiple of PAGE_SIZE.
+/// @param flag controls the behaviour of the function.
+/// @return the shared memory identifier, -1 on failure, and errno is set to
+/// indicate the error.
+long shmget(key_t key, size_t size, int flag);
+
+/// @brief Attaches the shared memory segment identified by shmid to the address
+/// space of the calling process.
+/// @param shmid the shared memory identifier.
+/// @param shmaddr the attaching address.
+/// @param shmflg controls the behaviour of the function.
+/// @return returns the address of the attached shared memory segment; on error
+/// (void *) -1 is returned, and errno is set to indicate the error.
+void * shmat(int shmid, const void *shmaddr, int shmflg);
+
+/// @brief Detaches the shared memory segment located at the address specified
+/// by shmaddr from the address space of the calling process
+/// @param shmaddr the address of the shared memory segment.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+long shmdt(const void *shmaddr);
+
+/// @brief Performs the control operation specified by cmd on the shared memory
+/// segment whose identifier is given in shmid.
+/// @param shmid the shared memory identifier.
+/// @param cmd the command to perform.
+/// @param buf is a pointer to a shmid_ds structure.
+/// @return a non-negative value basedon on the requested operation, -1 on
+/// failure and errno is set to indicate the error.
+long shmctl(int shmid, int cmd, struct shmid_ds *buf);
+
+#endif

libc/inc/libgen.h

@@ -0,0 +1,40 @@
+/// @file libgen.h
+/// @brief String routines.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "stddef.h"
+
+// TODO: doxygen comment.
+/// @brief
+/// @param out
+/// @param cur
+/// @param sep
+/// @param max
+/// @result
+int parse_path(char *out, char **cur, char sep, size_t max);
+
+// TODO: doxygen comment.
+/// @brief
+/// @param path
+/// @result
+char *dirname(const char *path);
+
+// TODO: doxygen comment.
+/// @brief
+/// @param path
+/// @result
+char *basename(const char *path);
+
+/// @brief Return the canonicalized absolute pathname.
+/// @param path     The path we are canonicalizing.
+/// @param resolved The canonicalized path.
+/// @return
+/// If there is no error, realpath() returns a pointer to the resolved.
+/// Otherwise, it returns NULL, the contents of the array resolved
+/// are undefined, and errno is set to indicate the error.
+/// @details
+/// If resolved is NULL, then realpath() uses malloc
+/// to allocate a buffer of up to PATH_MAX bytes to hold the
+/// resolved pathname, and returns a pointer to this buffer.
+char *realpath(const char *path, char *resolved);

libc/inc/limits.h

@@ -0,0 +1,57 @@
+/// @file limits.h
+/// @brief OS numeric limits.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// Number of bits in a `char'.
+#define CHAR_BIT 8
+
+/// Minimum value a `signed char' can hold.
+#define SCHAR_MIN -128
+
+/// Maximum value a `signed char' can hold.
+#define SCHAR_MAX +127
+
+/// Minimum value a `signed char' can hold.
+#define CHAR_MIN SCHAR_MIN
+
+/// Maximum value a `signed char' can hold.
+#define CHAR_MAX SCHAR_MAX
+
+/// Maximum value a `char' can hold.
+#define UCHAR_MAX 255
+
+/// Minimum value a `signed short int' can hold.
+#define SHRT_MIN (-32768)
+
+/// Maximum value a `signed short int' can hold.
+#define SHRT_MAX (+32767)
+
+/// Maximum value a `unsigned short int' can hold.
+#define USHRT_MAX 65535
+
+/// Minimum value a `signed int' can hold.
+#define INT_MIN (-2147483648)
+
+/// Maximum values a `signed int' can hold.
+#define INT_MAX (+2147483647)
+
+/// Maximum value an `unsigned int' can hold.
+#define UINT_MAX (+2147483647)
+
+/// Maximum value a `signed long int' can hold.
+#define LONG_MIN (-2147483648L)
+
+/// Minimum value a `signed long int' can hold.
+#define LONG_MAX (+2147483647L)
+
+/// Maximum number of characters in a file name.
+#define NAME_MAX 255
+
+/// Maximum number of characters in a path name.
+#define PATH_MAX 4096
+
+/// Maximum pid number.
+#define PID_MAX_LIMIT 32768

libc/inc/math.h

@@ -0,0 +1,157 @@
+/// @file math.h
+/// @brief Mathematical constants and functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief The absolute value.
+#define abs(a) (((a) < 0) ? -(a) : (a))
+
+/// @brief The max of the two values.
+#define max(a, b) (((a) > (b)) ? (a) : (b))
+
+/// @brief The min of the two values.
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+
+/// @brief The sign the the passed value.
+#define sign(x) ((x < 0) ? -1 : ((x > 0) ? 1 : 0))
+
+/// @brief e
+#define M_E 2.7182818284590452354
+
+/// @brief log_2 e
+#define M_LOG2E 1.4426950408889634074
+
+/// @brief log_10 e
+#define M_LOG10E 0.43429448190325182765
+
+/// @brief log_e 2
+#define M_LN2 0.69314718055994530942
+
+/// @brief log_e 10
+#define M_LN10 2.30258509299404568402
+
+/// @brief pi
+#define M_PI 3.14159265358979323846
+
+/// @brief pi / 2
+#define M_PI_2 1.57079632679489661923
+
+/// @brief pi / 4
+#define M_PI_4 0.78539816339744830962
+
+/// @brief 1 / pi
+#define M_1_PI 0.31830988618379067154
+
+/// @brief 2 / pi
+#define M_2_PI 0.63661977236758134308
+
+/// @brief 2 / sqrt(pi)
+#define M_2_SQRTPI 1.12837916709551257390
+
+/// @brief sqrt(2)
+#define M_SQRT2 1.41421356237309504880
+
+/// @brief  1 / sqrt(2)
+#define M_SQRT1_2 0.70710678118654752440
+
+/// @brief Returns the integral value that is nearest to x, with
+///        halfway cases rounded away from zero.
+/// @param x Value to round.
+/// @result The value of x rounded to the nearest integral
+///         (as a floating-point value).
+double round(double x);
+
+/// @brief Rounds x upward, returning the smallest integral value
+///        that is not less than x.
+/// @param x Value to round up.
+/// @return The smallest integral value that is not less than x
+///         (as a floating-point value).
+double ceil(double x);
+
+/// @brief Rounds x downward, returning the largest integral value
+///        that is not greater than x.
+/// @param x Value to round down.
+/// @return The value of x rounded downward (as a floating-point value).
+double floor(double x);
+
+/// @brief Returns base raised to the power exponent:
+/// @param base     Base value.
+/// @param exponent Exponent value.
+/// @result The result of raising base to the power exponent.
+/// @details
+/// If the base is finite negative and the exponent is finite but not an
+///  integer value, it causes a domain error.
+/// If both base and exponent are zero, it may also cause a domain error
+///  on certain implementations.
+/// If base is zero and exponent is negative, it may cause a domain error
+///  or a pole error (or none, depending on the library implementation).
+/// The function may also cause a range error if the result is too great
+///  or too small to be represented by a value of the return type.
+double pow(double base, double exponent);
+
+/// @brief Returns the base-e exponential function of x, which is e raised
+///        to the power x: e^x.
+/// @param x Value of the exponent.
+/// @return Exponential value of x.
+/// @details
+/// If the magnitude of the result is too large to be represented by a value
+///  of the return type, the function returns HUGE_VAL (or HUGE_VALF or
+///  HUGE_VALL) with the proper sign, and an overflow range error occurs and
+///  the global variable errno is set to ERANGE.
+double exp(double x);
+
+/// @brief Returns the absolute value of x: |x|.
+/// @param x Value whose absolute value is returned.
+/// @result The absolute value of x.
+double fabs(double x);
+
+/// @brief Returns the absolute value of x: |x|.
+/// @param x Value whose absolute value is returned.
+/// @result The absolute value of x.
+float fabsf(float x);
+
+/// @brief Returns the square root of x.
+/// @param x Value whose square root is computed.
+/// @return Square root of x. If x is negative, the global variable errno
+///         is set to EDOM.
+double sqrt(double x);
+
+/// @brief Returns the square root of x.
+/// @param x Value whose square root is computed.
+/// @return Square root of x. If x is negative, the global variable errno
+///         is set to EDOM.
+float sqrtf(float x);
+
+/// @brief Checks if the input value is Infinite (INF).
+/// @param x The value to check.
+/// @return 1 if INF, 0 otherwise.
+int isinf(double x);
+
+/// @brief Checks if the input value is Not A Number (NAN).
+/// @param x The value to check.
+/// @return 1 if NAN, 0 otherwise.
+int isnan(double x);
+
+/// @brief Logarithm function in base 10.
+/// @param x Topic of the logarithm function.
+/// @return Return the result.
+double log10(double x);
+
+/// @brief Natural logarithm function.
+/// @param x Topic of the logarithm function.
+/// @return Return the result.
+double ln(double x);
+
+/// @brief Logarithm function in base x.
+/// @param x Base of the logarithm.
+/// @param y Topic of the logarithm function.
+/// @return Return the result.
+double logx(double x, double y);
+
+/// @brief Breaks x into an integral and a fractional part, both parts have the same sign as x.
+/// @param x       The value we want to break.
+/// @param intpart Where we store the integer part.
+/// @return the fractional part.
+double modf(double x, double *intpart);

libc/inc/pwd.h

@@ -0,0 +1,55 @@
+/// @file pwd.h
+/// @brief Contains the structure and functions for managing passwords.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// @brief Stores user account information.
+typedef struct passwd_t {
+    char *pw_name;   ///< User's login name.
+    char *pw_passwd; ///< Encrypted password (not currently).
+    uid_t pw_uid;    ///< User ID.
+    gid_t pw_gid;    ///< Group ID.
+    char *pw_gecos;  ///< User's full name.
+    char *pw_dir;    ///< User's login directory.
+    char *pw_shell;  ///< User's login shell.
+} passwd_t;
+
+/// @brief Provides access to the password database entry for `name`.
+/// @param name The name to search inside the database.
+/// @return A pointer to the structure containing the database entry.
+passwd_t *getpwnam(const char *name);
+
+/// @brief Provides access to the password database entry for `uid`.
+/// @param uid The uid to search inside the database.
+/// @return A pointer to the structure containing the database entry.
+passwd_t *getpwuid(uid_t uid);
+
+/// @brief Provides the same information as getpwnam but it stores the
+///        results inside pwd, and the string information are store store
+///        inside `buf`.
+/// @param name   The name to search inside the database.
+/// @param pwd    The structure containing pointers to the entry fields.
+/// @param buf    The buffer where the strings should be stored.
+/// @param buflen The lenght of the buffer.
+/// @param result A pointer to the result or NULL is stored here.
+/// @return If the entry was found returns zero and set *result to pwd,
+///         if the entry was not found returns zero and set *result to NULL,
+///         on failure returns a number and sets  and set *result to NULL.
+int getpwnam_r(const char *name, passwd_t *pwd, char *buf, size_t buflen, passwd_t **result);
+
+/// @brief Provides the same information as getpwuid but it stores the
+///        results inside pwd, and the string information are store store
+///        inside `buf`.
+/// @param uid    The uid to search inside the database.
+/// @param pwd    The structure containing pointers to the entry fields.
+/// @param buf    The buffer where the strings should be stored.
+/// @param buflen The lenght of the buffer.
+/// @param result A pointer to the result or NULL is stored here.
+/// @return If the entry was found returns zero and set *result to pwd,
+///         if the entry was not found returns zero and set *result to NULL,
+///         on failure returns a number and sets  and set *result to NULL.
+int getpwuid_r(uid_t uid, passwd_t *pwd, char *buf, size_t buflen, passwd_t **result);

libc/inc/ring_buffer.h

@@ -0,0 +1,127 @@
+/// @file ring_buffer.h
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Declares a fixed-size ring-buffer.
+#define DECLARE_FIXED_SIZE_RING_BUFFER(type, name, length, init)                     \
+    typedef struct fs_rb_##name##_t {                                                \
+        unsigned size, read, write;                                                  \
+        type buffer[length];                                                         \
+    } fs_rb_##name##_t;                                                              \
+    static inline void fs_rb_##name##_init(fs_rb_##name##_t *rb)                     \
+    {                                                                                \
+        rb->size = length;                                                           \
+        rb->read = rb->write = 0;                                                    \
+        char *dst            = (char *)rb->buffer;                                   \
+        long num             = sizeof(type) * length;                                \
+        while (num--) *dst++ = (char)(init & 0xFF);                                  \
+    }                                                                                \
+    static inline unsigned fs_rb_##name##_step(fs_rb_##name##_t *rb, unsigned index) \
+    {                                                                                \
+        return (index == (rb->size - 1)) ? 0 : index + 1;                            \
+    }                                                                                \
+    static inline void fs_rb_##name##_push_front(fs_rb_##name##_t *rb, type item)    \
+    {                                                                                \
+        if (fs_rb_##name##_step(rb, rb->write) == rb->read)                          \
+            rb->read = fs_rb_##name##_step(rb, rb->read);                            \
+        rb->buffer[rb->write] = item;                                                \
+        rb->write             = fs_rb_##name##_step(rb, rb->write);                  \
+    }                                                                                \
+    static inline type fs_rb_##name##_empty(fs_rb_##name##_t *rb)                    \
+    {                                                                                \
+        return rb->write == rb->read;                                                \
+    }                                                                                \
+    static inline type fs_rb_##name##_pop_back(fs_rb_##name##_t *rb)                 \
+    {                                                                                \
+        type item = init;                                                            \
+        if (!fs_rb_##name##_empty(rb)) {                                             \
+            item     = rb->buffer[rb->read];                                         \
+            rb->read = fs_rb_##name##_step(rb, rb->read);                            \
+        }                                                                            \
+        return item;                                                                 \
+    }                                                                                \
+    static inline type fs_rb_##name##_pop_front(fs_rb_##name##_t *rb)                \
+    {                                                                                \
+        if (fs_rb_##name##_empty(rb))                                                \
+            return init;                                                             \
+        rb->write = (rb->write > 0) ? rb->write - 1 : rb->size - 1;                  \
+        return rb->buffer[rb->write];                                                \
+    }                                                                                \
+    static inline type fs_rb_##name##_get(fs_rb_##name##_t *rb, unsigned index)      \
+    {                                                                                \
+        if (index < rb->size)                                                        \
+            return rb->buffer[index];                                                \
+        return init;                                                                 \
+    }                                                                                \
+    static inline type fs_rb_##name##_back(fs_rb_##name##_t *rb)                     \
+    {                                                                                \
+        if (fs_rb_##name##_empty(rb))                                                \
+            return init;                                                             \
+        return rb->buffer[rb->read];                                                 \
+    }                                                                                \
+    static inline type fs_rb_##name##_front(fs_rb_##name##_t *rb)                    \
+    {                                                                                \
+        if (fs_rb_##name##_empty(rb))                                                \
+            return init;                                                             \
+        return rb->buffer[(rb->write > 0) ? rb->write - 1 : rb->size - 1];           \
+    }
+
+#ifdef __KERNEL__
+/// Function for allocating memory for the ring buffer.
+#define RING_BUFFER_ALLOC kmalloc
+/// Function for freeing the memory for the ring buffer.
+#define RING_BUFFER_FREE  kfree
+#else
+/// Function for allocating memory for the ring buffer.
+#define RING_BUFFER_ALLOC malloc
+/// Function for freeing the memory for the ring buffer.
+#define RING_BUFFER_FREE  free
+#endif
+
+/// @brief Declares a dynamic-size ring-buffer.
+#define DECLARE_RING_BUFFER(type, name, init)                                                       \
+    typedef struct rb_##name##_t {                                                                  \
+        const unsigned size;                                                                        \
+        unsigned read, write;                                                                       \
+        type *buffer;                                                                               \
+    } rb_##name##_t;                                                                                \
+    static inline rb_##name##_t alloc_rb_##name(unsigned len)                                       \
+    {                                                                                               \
+        rb_##name##_t rb = { len, 0U, 0U, len > 0 ? RING_BUFFER_ALLOC(sizeof(type) * len) : NULL }; \
+        memset(rb.buffer, init, sizeof(type) * len);                                                \
+        return rb;                                                                                  \
+    }                                                                                               \
+    static inline void free_rb_##name(rb_##name##_t *rb)                                            \
+    {                                                                                               \
+        RING_BUFFER_FREE(rb->buffer);                                                               \
+    }                                                                                               \
+    static inline unsigned step_rb_##name(rb_##name##_t *rb, unsigned index)                        \
+    {                                                                                               \
+        return (index == (rb->size - 1)) ? 0 : index + 1;                                           \
+    }                                                                                               \
+    static inline void push_rb_##name(rb_##name##_t *rb, type item)                                 \
+    {                                                                                               \
+        if (step_rb_##name(rb, rb->write) == rb->read)                                              \
+            rb->read = step_rb_##name(rb, rb->read);                                                \
+        rb->buffer[rb->write] = item;                                                               \
+        rb->write             = step_rb_##name(rb, rb->write);                                      \
+    }                                                                                               \
+    static inline void pop_rb_##name(rb_##name##_t *rb, type *item)                                 \
+    {                                                                                               \
+        *item = init;                                                                               \
+        if (rb->write != rb->read) {                                                                \
+            *item    = rb->buffer[rb->read];                                                        \
+            rb->read = step_rb_##name(rb, rb->read);                                                \
+        }                                                                                           \
+    }                                                                                               \
+    static inline void get_rb_##name(rb_##name##_t *rb, unsigned index, type *item)                 \
+    {                                                                                               \
+        if (index < rb->size)                                                                       \
+            *item = rb->buffer[index];                                                              \
+    }
+
+#undef RING_BUFFER_ALLOC
+#undef RING_BUFFER_FREE

libc/inc/sched.h

@@ -0,0 +1,43 @@
+/// @file sched.h
+/// @brief Structures and functions for managing the scheduler.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "sys/types.h"
+#include "time.h"
+#include "stdbool.h"
+
+/// @brief Structure that describes scheduling parameters.
+typedef struct sched_param_t {
+    /// Static execution priority.
+    int sched_priority;
+    /// Expected period of the task
+    time_t period;
+    /// Absolute deadline
+    time_t deadline;
+    /// Absolute time of arrival of the task
+    time_t arrivaltime;
+    /// Is task periodic?
+    bool_t is_periodic;
+} sched_param_t;
+
+/// @brief Sets scheduling parameters.
+/// @param pid pid of the process we want to change the parameters. If zero,
+/// then the parameters of the calling process are set.
+/// @param param The interpretation of the argument param depends on the
+/// scheduling policy of the thread identified by pid.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int sched_setparam(pid_t pid, const sched_param_t *param);
+
+/// @brief Gets scheduling parameters.
+/// @param pid pid of the process we want to retrieve the parameters. If zero,
+/// then the parameters of the calling process are returned.
+/// @param param The interpretation of the argument param depends on the
+/// scheduling policy of the thread identified by pid.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int sched_getparam(pid_t pid, sched_param_t *param);
+
+/// @brief Placed at the end of an infinite while loop, stops the process until,
+/// its next period starts. The calling process must be a periodic one.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int waitperiod();

libc/inc/signal.h

@@ -0,0 +1,272 @@
+/// @file signal.h
+/// @brief Signals definition.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "sys/types.h"
+
+/// @brief List of signals.
+typedef enum {
+    SIGHUP    = 1,  ///< Hang up detected on controlling terminal or death of controlling process.
+    SIGINT    = 2,  ///< Issued if the user sends an interrupt signal (Ctrl + C).
+    SIGQUIT   = 3,  ///< Issued if the user sends a quit signal (Ctrl + D).
+    SIGILL    = 4,  ///< Illegal Instruction.
+    SIGTRAP   = 5,  ///< Trace/breakpoint trap.
+    SIGABRT   = 6,  ///< Abort signal from abort().
+    SIGEMT    = 7,  ///< Emulator trap.
+    SIGFPE    = 8,  ///< Floating-point arithmetic exception.
+    SIGKILL   = 9,  ///< If a process gets this signal it must quit immediately and will not perform any clean-up operations.
+    SIGBUS    = 10, ///< Bus error (bad memory access).
+    SIGSEGV   = 11, ///< Invalid memory reference.
+    SIGSYS    = 12, ///< Bad system call (SVr4).
+    SIGPIPE   = 13, ///< Broken pipe: write to pipe with no readers.
+    SIGALRM   = 14, ///< Alarm clock signal (used for timers).
+    SIGTERM   = 15, ///< Software termination signal (sent by kill by default).
+    SIGUSR1   = 16, ///< User-defined signal 1.
+    SIGUSR2   = 17, ///< User-defined signal 2.
+    SIGCHLD   = 18, ///< Child stopped or terminated.
+    SIGPWR    = 19, ///< Power failure.
+    SIGWINCH  = 20, ///< Window resize signal.
+    SIGURG    = 21, ///< Urgent condition on socket.
+    SIGPOLL   = 22, ///< Pollable event.
+    SIGSTOP   = 23, ///< Stop process.
+    SIGTSTP   = 24, ///< Stop typed at terminal.
+    SIGCONT   = 25, ///< Continue if stopped.
+    SIGTTIN   = 26, ///< Terminal input for background process.
+    SIGTTOU   = 27, ///< Terminal output for background process.
+    SIGVTALRM = 28, ///< Virtual alarm clock.
+    SIGPROF   = 29, ///< Profiling timer expired.
+    SIGXCPU   = 30, ///< CPU time limit exceeded.
+    SIGXFSZ   = 31, ///< File size limit exceeded.
+    NSIG
+} signal_type_t;
+
+/// @brief Codes that indentify the sender of a signal.
+typedef enum {
+    SI_NOINFO, ///< Unable to determine complete signal information.
+
+    // Signal         : -
+    // Enabled fields : si_pid, si_uid
+    SI_USER, ///< Signal sent by kill(), pthread_kill(), raise(), abort() or alarm().
+
+    // Signal         : -
+    // Enabled fields : -
+    SI_KERNEL, ///< Generic kernel function
+
+    // Signal         : -
+    // Enabled fields : si_pid, si_uid, si_value
+    SI_QUEUE,   ///< Signal was sent by sigqueue().
+    SI_TIMER,   ///< Signal was generated by expiration of a timer set by timer_settimer().
+    SI_ASYNCIO, ///< Signal was generated by completion of an asynchronous I/O request.
+    SI_MESGQ,   ///< Signal was generated by arrival of a message on an empty message queue.
+
+    // Signal         : SIGILL
+    // Enabled fields : si_addr (address of failing instruction)
+    ILL_ILLOPC, ///< Illegal opcode.
+    ILL_ILLOPN, ///< Illegal operand.
+    ILL_ILLADR, ///< Illegal addressing mode.
+    ILL_ILLTRP, ///< Illegal trap.
+    ILL_PRVOPC, ///< Privileged opcode.
+    ILL_PRVREG, ///< Privileged register.
+    ILL_COPROC, ///< Coprocessor error.
+    ILL_BADSTK, ///< Internal stack error.
+
+    // Signal         : SIGFPE
+    // Enabled fields : si_addr (address of failing instruction)
+    FPE_INTDIV, ///< Integer divide-by-zero.
+    FPE_INTOVF, ///< Integer overflow.
+    FPE_FLTDIV, ///< Floating point divide-by-zero.
+    FPE_FLTOVF, ///< Floating point overflow.
+    FPE_FLTUND, ///< Floating point underflow.
+    FPE_FLTRES, ///< Floating point inexact result.
+    FPE_FLTINV, ///< Invalid floating point operation.
+    FPE_FLTSUB, ///< Subscript out of range.
+
+    // Signal         : SIGSEGV
+    // Enabled fields : si_addr (address of faulting memory reference)
+    SEGV_MAPERR, ///< Address not mapped.
+    SEGV_ACCERR, ///< Invalid permissions.
+
+    // Signal         : SIGBUS
+    // Enabled fields : si_addr (address of faulting memory reference)
+    BUS_ADRALN, ///< Invalid address alignment.
+    BUS_ADRERR, ///< Non-existent physical address.
+    BUS_OBJERR, ///< Object-specific hardware error.
+
+    // Signal         : SIGTRAP
+    // Enabled fields : -
+    TRAP_BRKPT, ///< Process breakpoint.
+    TRAP_TRACE, ///< Process trace trap.
+
+    // Signal         : SIGCHLD
+    // Enabled fields : si_pid (child process ID)
+    //                  si_uid (real user ID of process that sent the signal)
+    //                  si_status (exit value or signal)
+    CLD_EXITED,    ///< Child has exited.
+    CLD_KILLED,    ///< Child has terminated abnormally and did not create a core file.
+    CLD_DUMPED,    ///< Child has terminated abnormally and created a core file.
+    CLD_TRAPPED,   ///< Traced child has trapped.
+    CLD_STOPPED,   ///< Child has stopped.
+    CLD_CONTINUED, ///< Stopped child has continued.
+
+    // Signal         : SIGIO/SIGPOLL
+    // Enabled fields : si_band
+    POLL_IN,  ///< Data input available.
+    POLL_OUT, ///< Output buffers available.
+    POLL_MSG, ///< Input message available.
+    POLL_ERR, ///< I/O error.
+    POLL_PRI, ///< High priority input available.
+    POLL_HUP, ///< Device disconnected.
+} signal_sender_code_t;
+
+/// @brief Defines what to do with the provided signal mask.
+typedef enum {
+    /// @brief The set of blocked signals is the union of the current set
+    ///        and the set argument.
+    SIG_BLOCK,
+    /// @brief The signals in set are removed from the current set of
+    ///        blocked signals. It is permissible to attempt to unblock
+    ///        a signal which is not blocked.
+    SIG_UNBLOCK,
+    /// @brief The set of blocked signals is set to the argument set.
+    SIG_SETMASK
+} sigmask_how_t;
+
+/// @defgroup SigactionFlags Flags associated with a sigaction.
+/// @{
+
+#define SA_NOCLDSTOP 0x00000001U ///< Turn off SIGCHLD when children stop.
+#define SA_NOCLDWAIT 0x00000002U ///< Flag on SIGCHLD to inhibit zombies.
+#define SA_SIGINFO   0x00000004U ///< sa_sigaction specifies the signal-handling function for signum.
+#define SA_ONSTACK   0x08000000U ///< Indicates that a registered stack_t will be used.
+#define SA_RESTART   0x10000000U ///< Flag to get restarting signals (which were the default long ago)
+#define SA_NODEFER   0x40000000U ///< Prevents the current signal from being masked in the handler.
+#define SA_RESETHAND 0x80000000U ///< Clears the handler when the signal is delivered.
+
+/// @}
+
+/// Type of a signal handler.
+typedef void (*sighandler_t)(int);
+
+#define SIG_DFL ((sighandler_t)0)  ///< Default signal handling.
+#define SIG_IGN ((sighandler_t)1)  ///< Ignore signal.
+#define SIG_ERR ((sighandler_t)-1) ///< Error return from signal.
+
+/// @brief Structure used to mask and unmask signals.
+/// @details
+/// Each unsigned long consists of 32 bits, thus, the maximum number of signals
+/// that may be declared is 64.
+/// Signals are divided into two cathegories, identified by the two unsigned longs:
+///     [ 1, 31] corresponds to normal signals;
+///     [32, 64] corresponds to real-time signals.
+typedef struct sigset_t {
+    /// Signals divided into two cathegories.
+    unsigned long sig[2];
+} sigset_t;
+
+/// @brief Holds the information on how to handle a specific signal.
+typedef struct sigaction_t {
+    /// This field specifies the type of action to be performed; its value can be a pointer
+    /// to the signal handler, SIG_DFL (that is, the value 0) to specify that the default
+    /// action is performed, or SIG_IGN (that is, the value 1) to specify that the signal is
+    /// ignored.
+    sighandler_t sa_handler;
+    /// This sigset_t variable specifies the signals to be masked when running the signal handler
+    sigset_t sa_mask;
+    /// This set of flags specifies how the signal must be handled;
+    unsigned int sa_flags;
+} sigaction_t;
+
+/// @brief Data passed with signal info.
+typedef union sigval {
+    int sival_int;   ///< Integer value.
+    void *sival_ptr; ///< Pointer value.
+} sigval_t;
+
+/// @brief Stores information about an occurrence of a specific signal.
+typedef struct siginfo_t {
+    /// The signal number.
+    int si_signo;
+    /// A code identifying who raised the signal (see signal_sender_code_t).
+    int si_code;
+    /// Signal value.
+    sigval_t si_value;
+    /// The error code of the instruction that caused the signal to be raised, or 0 if there was no error.
+    int si_errno;
+    /// Process ID of sending process.
+    pid_t si_pid;
+    /// Real user ID of sending process.
+    uid_t si_uid;
+    /// Address at which fault occurred.
+    void *si_addr;
+    /// Exit value or signal for process termination.
+    int si_status;
+    /// Band event for SIGPOLL/SIGIO.
+    int si_band;
+} siginfo_t;
+
+/// @brief Send signal to a process.
+/// @param pid The pid of the process to which we send the signal.
+/// @param sig The type of signal to send.
+/// @return On success 0, on error -1 and errno is set appropriately.
+int kill(pid_t pid, int sig);
+
+/// @brief Sets the disposition of the signal signum to handler.
+/// @param signum  The signal number.
+/// @param handler The handler for the signal.
+/// @return The previous value of the signal handler, or SIG_ERR on error.
+sighandler_t signal(int signum, sighandler_t handler);
+
+/// @brief Examine and change a signal action.
+/// @param signum Specifies the signal and can be any valid signal except SIGKILL and SIGSTOP.
+/// @param act    If non-NULL, the new action for signal signum is installed from act.
+/// @param oldact If non-NULL, the previous action is saved in oldact.
+/// @return returns 0 on success; on error, -1 is returned, and errno is set to indicate the error.
+int sigaction(int signum, const sigaction_t *act, sigaction_t *oldact);
+
+/// @brief Examine and change blocked signals.
+/// @param how    Determines the behavior of the call.
+/// @param set    The set of signals to manage by the function.
+/// @param oldset If non-NULL, the previous value of the signal mask is stored here.
+/// @return returns 0 on success, and -1 on error (errno is set to indicate the cause).
+/// @details
+/// If set is NULL, then the signal mask is unchanged (i.e., how is
+///  ignored), but the current value of the signal mask is
+///  nevertheless returned in oldset (if it is not NULL).
+int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
+
+/// @brief Returns the string describing the given signal.
+/// @param sig The signal to inquire.
+/// @return String representing the signal.
+const char *strsignal(int sig);
+
+/// @brief Prepare an empty set.
+/// @param set The set to manipulate.
+/// @return 0 on success and -1 on error.
+int sigemptyset(sigset_t *set);
+
+/// @brief Prepare a full set.
+/// @param set The set to manipulate.
+/// @return 0 on success and -1 on error.
+int sigfillset(sigset_t *set);
+
+/// @brief Adds the given signal to the correct set.
+/// @param set    The set to manipulate.
+/// @param signum The signalt to handle.
+/// @return 0 on success and -1 on error.
+int sigaddset(sigset_t *set, int signum);
+
+/// @brief Removes the given signal to the correct set.
+/// @param set    The set to manipulate.
+/// @param signum The signalt to handle.
+/// @return 0 on success and -1 on error.
+int sigdelset(sigset_t *set, int signum);
+
+/// @brief Checks if the given signal is part of the set.
+/// @param set    The set to manipulate.
+/// @param signum The signalt to handle.
+/// @return 1 if signum is a member of set,
+///         0 if signum is not a member, and -1 on error.
+int sigismember(sigset_t *set, int signum);

libc/inc/stdarg.h

@@ -1,7 +1,6 @@
-///                MentOS, The Mentoring Operating system project
 /// @file stdarg.h
-/// @brief
-/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// @brief Contains the macros required to manage variable number of arguments.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
 /// See LICENSE.md for details.
 
 #pragma once
@@ -16,7 +15,7 @@ typedef char *va_list;
 
 /// @brief Amount of space required in an argument list (ie. the stack) for an
 /// argument of type t.
-#define va_size(t)                                                             \
+#define va_size(t) \
     (((sizeof(t) + sizeof(va_item) - 1) / sizeof(va_item)) * sizeof(va_item))
 
 /// @brief The start of a variadic list.

libc/inc/stdbool.h

@@ -0,0 +1,12 @@
+/// @file stdbool.h
+/// @brief Defines the boolean values.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Define boolean value.
+typedef enum bool_t {
+    false, ///< [0] False.
+    true ///< [1] True.
+} __attribute__((__packed__)) bool_t;

libc/inc/stddef.h

@@ -0,0 +1,70 @@
+/// @file stddef.h
+/// @brief Define basic data types.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#ifndef NULL
+/// @brief Define NULL.
+#define NULL ((void *)0)
+#endif
+
+#ifndef EOF
+/// @brief Define End-Of-File.
+#define EOF (-1)
+#endif
+
+/// @brief Define the size of a buffer.
+#define BUFSIZ 512
+
+/// Is the signed integer type of the result of subtracting two pointers.
+typedef long signed int ptrdiff_t;
+
+/// Define the byte type.
+typedef unsigned char byte_t;
+
+/// Define the generic size type.
+typedef unsigned long size_t;
+
+/// Define the generic signed size type.
+typedef long ssize_t;
+
+/// Define the type of an inode.
+typedef unsigned int ino_t;
+
+/// Used for device IDs.
+typedef unsigned int dev_t;
+
+/// The type of user-id.
+typedef unsigned int uid_t;
+
+/// The type of group-id.
+typedef unsigned int gid_t;
+
+/// The type of offset.
+typedef long int off_t;
+
+/// The type of mode.
+typedef unsigned int mode_t;
+
+/// This data-type is used to set protection bits of pages.
+typedef unsigned int pgprot_t;
+
+/// It evaluates to the offset (in bytes) of a given member within
+/// a struct or union type, an expression of type size_t.
+#define offsetof(type, member) \
+    ((size_t) & (((type *)0)->member))
+
+/// Retrieve an enclosing structure from a pointer to a nested element.
+#if 1
+#define container_of(ptr, type, member) \
+    ((type *)((char *)(1 ? (ptr) : &((type *)0)->member) - offsetof(type, member)))
+#else
+#define container_of(ptr, type, member) \
+    ((type *)((char *)ptr - offsetof(type, member)))
+#endif
+
+/// Returns the alignment, in bytes, of the specified type.
+#define alignof(type) offsetof( \
+    struct { char c; type member; }, member)

libc/inc/stdint.h

@@ -1,7 +1,6 @@
-///                MentOS, The Mentoring Operating system project
 /// @file stdint.h
-/// @brief
-/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// @brief Standard integer data-types.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
 /// See LICENSE.md for details.
 
 #pragma once

libc/inc/stdio.h

@@ -0,0 +1,126 @@
+/// @file stdio.h
+/// @brief Standard I/0 functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stdarg.h"
+#include "stddef.h"
+
+/// @brief The maximum number of digits of an integer.
+#define MAX_DIGITS_IN_INTEGER 11
+/// @brief The size of 'gets' buffer.
+#define GETS_BUFFERSIZE 255
+
+#ifndef EOF
+/// @brief Define the End-Of-File.
+#define EOF (-1)
+#endif
+
+#define SEEK_SET 0 ///< The file offset is set to offset bytes.
+#define SEEK_CUR 1 ///< The file offset is set to its current location plus offset bytes.
+#define SEEK_END 2 ///< The file offset is set to the size of the file plus offset bytes.
+
+#ifndef __KERNEL__
+/// @brief Writes the given character to the standard output (stdout).
+/// @param character The character to send to stdout.
+void putchar(int character);
+
+/// @brief Writes the string pointed by str to the standard output (stdout)
+///        and appends a newline character.
+/// @param str The string to send to stdout.
+void puts(char *str);
+
+/// @brief Returns the next character from the standard input (stdin).
+/// @return The character received from stdin.
+int getchar();
+
+/// @brief Reads characters from the standard input (stdin).
+/// @param str Where the characters are stored.
+/// @return The string received from standard input.
+char *gets(char *str);
+
+/// @brief Same as getchar but reads from the given file descriptor.
+/// @param fd The file descriptor from which it reads.
+/// @return The read character.
+int fgetc(int fd);
+
+/// @brief Same as gets but reads from the given file descriptor.
+/// @param buf The buffer where the string should be placed.
+/// @param n   The amount of characters to read.
+/// @param fd  The file descriptor from which it reads.
+/// @return The read string.
+char *fgets(char *buf, int n, int fd);
+#endif
+
+/// @brief Convert the given string to an integer.
+/// @param str The string to convert.
+/// @return The integer contained inside the string.
+int atoi(const char *str);
+
+/// @brief Converts the initial part of `str` to a long int value according to
+///        the given base, which.
+/// @param str    This is the string containing the integral number.
+/// @param endptr Set to the character after the numerical value.
+/// @param base   The base must be between 2 and 36 inclusive, or special 0.
+/// @return Integral number as a long int value, else zero value is returned.
+long strtol(const char *str, char **endptr, int base);
+
+/// @brief Write formatted output to stdout.
+/// @param fmt The format string.
+/// @param ... The list of arguments.
+/// @return On success, the total number of characters written is returned.
+///         On failure, a negative number is returned.
+int printf(const char *fmt, ...);
+
+/// @brief Write formatted output to `str`.
+/// @param str The buffer where the formatted string will be placed.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param ... The list of arguments.
+/// @return On success, the total number of characters written is returned.
+///         On failure, a negative number is returned.
+int sprintf(char *str, const char *fmt, ...);
+
+#ifndef __KERNEL__
+/// @brief The same as sprintf, but it putput on file.
+/// @param fd  The file descriptor associated with the file.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param ... The list of arguments.
+/// @return On success, the total number of characters written is returned.
+///         On failure, a negative number is returned.
+int fprintf(int fd, const char *fmt, ...);
+#endif
+
+/// @brief Write formatted data from variable argument list to string.
+/// @param str  Pointer to a buffer where the resulting C-string is stored.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param args A variable arguments list.
+/// @return On success, the total number of characters written is returned.
+///         On failure, a negative number is returned.
+int vsprintf(char *str, const char *fmt, va_list args);
+
+#ifndef __KERNEL__
+/// @brief Read formatted input from stdin.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param ... The list of arguments where the values are stored.
+/// @return On success, the function returns the number of items of the
+///         argument list successfully filled. EOF otherwise.
+int scanf(const char *fmt, ...);
+
+/// @brief Read formatted data from string.
+/// @param str String processed as source to retrieve the data.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param ... The list of arguments where the values are stored.
+/// @return On success, the function returns the number of items of the
+///         argument list successfully filled. EOF otherwise.
+int sscanf(const char *str, const char *fmt, ...);
+
+/// @brief The same as sscanf but the source is a file.
+/// @param fd  The file descriptor associated with the file.
+/// @param fmt  Format string, following the same specifications as printf.
+/// @param ... The list of arguments where the values are stored.
+/// @return On success, the function returns the number of items of the
+///         argument list successfully filled. EOF otherwise.
+int fscanf(int fd, const char *fmt, ...);
+#endif

libc/inc/stdlib.h

@@ -0,0 +1,70 @@
+/// @file stdlib.h
+/// @brief Useful generic functions and macros.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// @brief Returns the number of usable bytes in the block pointed to by ptr.
+/// @param ptr The pointer for which we want to retrieve the usable size.
+/// @return The number of usable bytes in the block of allocated memory
+///         pointed to by ptr. If ptr is not a valid pointer, 0 is returned.
+size_t malloc_usable_size(void *ptr);
+
+/// @brief Provides dynamically allocated memory.
+/// @param size The amount of memory to allocate.
+/// @return A pointer to the allocated memory.
+void *malloc(unsigned int size);
+
+/// @brief Allocates a block of memory for an array of num elements.
+/// @param num  The number of elements.
+/// @param size The size of an element.
+/// @return A pointer to the allocated memory.
+void *calloc(size_t num, size_t size);
+
+/// @brief Reallocates the given area of memory.
+/// @param ptr  The pointer to the memory to reallocate.
+/// @param size The new size for the memory.
+/// @return A pointer to the new portion of memory.
+/// @details
+/// It must be previously allocated by malloc(), calloc() or realloc() and
+/// not yet freed with a call to free or realloc. Otherwise, the results
+/// are undefined.
+void *realloc(void *ptr, size_t size);
+
+/// @brief Frees dynamically allocated memory.
+/// @param ptr The pointer to the allocated memory.
+void free(void *ptr);
+
+/// The maximum value returned by the rand function.
+#define RAND_MAX ((1U << 31U) - 1U)
+
+/// @brief Allows to set the seed of the random value generator.
+/// @param x The new seed.
+void srand(int x);
+
+/// @brief Generates a random value.
+/// @return The random value.
+int rand();
+
+/// @brief Cause an abnormal program termination with core-dump.
+void abort();
+
+/// @brief Tries to adds the variable to the environment.
+/// @param name      Name of the variable.
+/// @param value     Value of the variable.
+/// @param overwrite Override existing variable value or not.
+/// @return Zero on success, or -1 on error with errno indicating the cause.
+int setenv(const char *name, const char *value, int overwrite);
+
+/// @brief Tries to remove the variable from the environment.
+/// @param name      Name of the variable.
+/// @return Zero on success, or -1 on error with errno indicating the cause.
+int unsetenv(const char *name);
+
+/// @brief Returns the value of the given variable.
+/// @param name Name of the variable.
+/// @return A pointer to the value, or NULL if there is no match.
+char *getenv(const char *name);

libc/inc/strerror.h

@@ -0,0 +1,13 @@
+/// @file strerror.h
+/// @brief Contains the function that transfornms an errno into a string.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include <sys/errno.h>
+
+/// @brief Returns the string representing the error number.
+/// @param errnum The error number.
+/// @return The string representing the error number.
+char *strerror(int errnum);

libc/inc/string.h

@@ -0,0 +1,310 @@
+/// @file string.h
+/// @brief String routines.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// @brief Copies the first num characters of source to destination.
+/// @param destination Pointer to the destination array where the content is to be copied.
+/// @param source      String to be copied.
+/// @param num         Maximum number of characters to be copied from source.
+/// @return destination is returned.
+char *strncpy(char *destination, const char *source, size_t num);
+
+/// @brief Compares up to n characters of s1 to those of s2.
+/// @param s1 First string to be compared.
+/// @param s2 Second string to be compared.
+/// @param n  Maximum number of characters to compare.
+/// @return
+/// Returns an integral value indicating the relationship between the strings:
+///     <0 the first character that does not match has a lower
+///        value in s1 than in s2
+///      0 the contents of both strings are equal
+///     >0 the first character that does not match has a greater
+///        value in s1 than in s2
+int strncmp(const char *s1, const char *s2, size_t n);
+
+/// @brief Case insensitive string compare.
+/// @param s1 First string to be compared.
+/// @param s2 Second string to be compared.
+/// @return
+/// Returns an integral value indicating the relationship between the strings:
+///     <0 the first character that does not match has a lower
+///        value in s1 than in s2
+///      0 the contents of both strings are equal
+///     >0 the first character that does not match has a greater
+///        value in s1 than in s2
+int stricmp(const char *s1, const char *s2);
+
+/// @brief Case-insensitively compare up to n characters of s1 to those of s2.
+/// @param s1 First string to be compared.
+/// @param s2 Second string to be compared.
+/// @param n  Maximum number of characters to compare.
+/// @return
+/// Returns an integral value indicating the relationship between the strings:
+///     <0 the first character that does not match has a lower
+///        value in s1 than in s2
+///      0 the contents of both strings are equal
+///     >0 the first character that does not match has a greater
+///        value in s1 than in s2
+int strnicmp(const char *s1, const char *s2, size_t n);
+
+/// @brief Returns a pointer to the first occurrence of ch in str.
+/// @param s  The string where the search is performed.
+/// @param ch Character to be located.
+/// @return A pointer to the first occurrence of character in str.
+char *strchr(const char *s, int ch);
+
+/// @brief Returns a pointer to the last occurrence of ch in str.
+/// @param s  The string where the search is performed.
+/// @param ch Character to be located.
+/// @return A pointer to the last occurrence of character in str.
+char *strrchr(const char *s, int ch);
+
+/// @brief Returns a pointer to the first occurrence of s2 in s1,
+///        or NULL if s2 is not part of s1.
+/// @param s1 String to be scanned
+/// @param s2 String containing the sequence of characters to match.
+/// @return A pointer to the first occurrence in s1 of the entire
+///         sequence of characters specified in s2, or a null pointer
+///         if the sequence is not present in s1.
+char *strstr(const char *s1, const char *s2);
+
+/// @brief Returns the length of the initial portion of string which consists
+///        only of characters that are part of control.
+/// @param string  String to be scanned.
+/// @param control String containing the characters to match.
+/// @return The number of characters in the initial segment of string which
+///         consist only of characters from control.
+size_t strspn(const char *string, const char *control);
+
+/// @brief Calculates the length of the initial segment of string which
+///        consists entirely of characters not in control.
+/// @param string  String to be scanned.
+/// @param control String containing the characters to match.
+/// @return The number of characters in the initial segment of string which
+///         consist only of characters that are not inside control.
+size_t strcspn(const char *string, const char *control);
+
+/// @brief Finds the first character in the string string that matches any
+///        character specified in control.
+/// @param string  String to be scanned.
+/// @param control String containing the characters to match.
+/// @return
+/// A pointer to the first occurrence in string of any of the characters
+/// that are part of control, or a null pointer if none of the characters
+/// of control is found in string before the terminating null-character.
+char *strpbrk(const char *string, const char *control);
+
+/// @brief Make a copy of the given string.
+/// @param s String to duplicate.
+/// @return On success, returns a pointer to the duplicated string.
+///         On failure, returns NULL with errno indicating the cause.
+char *strdup(const char *s);
+
+/// @brief Make a copy of at most n bytes of the given string.
+/// @param s String to duplicate.
+/// @param n The number of character to duplicate.
+/// @return On success, returns a pointer to the duplicated string.
+///         On failure, returns NULL with errno indicating the cause.
+char *strndup(const char *s, size_t n);
+
+/// @brief Appends a copy of the string src to the string dst.
+/// @param dst Pointer to the destination array, which should be large enough
+///            to contain the concatenated resulting string.
+/// @param src String to be appended. This should not overlap dst.
+/// @return destination is returned.
+char *strcat(char *dst, const char *src);
+
+/// @brief Appends a copy of the string src to the string dst, up to n bytes.
+/// @param dst Pointer to the destination array, which should be large enough
+///            to contain the concatenated resulting string.
+/// @param src String to be appended. This should not overlap dst.
+/// @param n   The number of bytes to copy.
+/// @return destination is returned.
+char *strncat(char *dst, const char *src, size_t n);
+
+/// @brief Fill the string s with the character c.
+/// @param s The string that you want to fill.
+/// @param c The character that you want to fill the string with.
+/// @return The address of the string, s.
+char *strset(char *s, int c);
+
+/// @brief Fill the string s with the character c, up to the given length n.
+/// @param s The string that you want to fill.
+/// @param c The character that you want to fill the string with.
+/// @param n The maximum number of bytes to fill.
+/// @return The address of the string, s.
+char *strnset(char *s, int c, size_t n);
+
+/// @brief Reverse the string s.
+/// @param s The given string which is needed to be reversed.
+/// @return The address of the string, s.
+char *strrev(char *s);
+
+/// @brief Splits string into tokens.
+/// @param str   String to truncate.
+/// @param delim String containing the delimiter characters.
+/// @return If a token is found, a pointer to the beginning of the token.
+///         Otherwise, a null pointer.
+/// @details
+/// Notice that str is modified by being broken into smaller strings (tokens).
+/// A null pointer may be specified, in which case the function continues
+/// scanning where a previous successful call to the function ended.
+char *strtok(char *str, const char *delim);
+
+/// @brief This function is a reentrant version strtok().
+/// @param str     String to truncate.
+/// @param delim   String containing the delimiter characters.
+/// @param saveptr Pointer used internally to maintain context between calls.
+/// @return
+/// @details
+/// The saveptr argument is a pointer to a char * variable that is used
+/// internally by strtok_r() in order to maintain context between successive
+/// calls that parse the same string.
+/// On the first call to strtok_r(), str should point to the string to be
+/// parsed, and the value of saveptr is ignored. In subsequent calls, str
+/// should be NULL, and saveptr should be unchanged since the previous call.
+char *strtok_r(char *str, const char *delim, char **saveptr);
+
+/// @brief Copies the values of num bytes from the location pointed by source
+/// to the memory block pointed by destination.
+/// @param dst Pointer to the destination array where the content is to be
+///            copied, type-casted to a pointer of type void*.
+/// @param src Pointer to the source of data to be copied, type-casted to
+///            a pointer of type const void*.
+/// @param n   Number of bytes to copy.
+/// @return A pointer to dst is returned.
+void *memmove(void *dst, const void *src, size_t n);
+
+/// @brief Searches for the first occurrence of the character c (an unsigned
+///        char) in the first n bytes of the string pointed to, by the
+///        argument str.
+/// @param ptr Pointer to the block of memory where the search is performed.
+/// @param c   Value to be located.
+/// @param n   Number of bytes to be analyzed.
+/// @return A pointer to the first occurrence of value in the block of memory.
+void *memchr(const void *ptr, int c, size_t n);
+
+/// @brief Converts a given string into lowercase.
+/// @param s String which we want to convert into lowercase.
+/// @return A pointer to s.
+char *strlwr(char *s);
+
+/// @brief Converts a given string into uppercase.
+/// @param s String which we want to convert into uppercase.
+/// @return A pointer to s.
+char *strupr(char *s);
+
+/// @brief The memccpy function copies no more than n bytes from memory
+///        area src to memory area dest, stopping when the character c is
+///        found.
+/// @param dst Points to the destination memory area.
+/// @param src Points to the source memory area.
+/// @param c   The delimiter used to stop.
+/// @param n   The maximum number of copied bytes.
+/// @return A pointer to the next character in dst after c, or NULL if c
+///         was not found in the first n characters of src.
+void *memccpy(void *dst, const void *src, int c, size_t n);
+
+/// @brief Copy a block of memory, handling overlap.
+/// @param dst Pointer to the destination.
+/// @param src Pointer to the source.
+/// @param num  Number of bytes to be copied.
+/// @return Pointer to the destination.
+void *memcpy(void *dst, const void *src, size_t num);
+
+/// @brief Compares the first n bytes of str1 and str2.
+/// @param ptr1 First pointer to block of memory.
+/// @param ptr2 Second pointer to block of memory.
+/// @param n    Number of bytes to compare.
+/// @return
+/// Returns an integral value indicating the relationship between
+/// the memory blocks:
+///     <0 the first byte that does not match has a lower
+///        value in ptr1 than in ptr2
+///      0 the contents of both memory blocks are equal
+///     >0 the first byte that does not match has a greater
+///        value in ptr1 than in ptr2
+int memcmp(const void *ptr1, const void *ptr2, size_t n);
+
+/// @brief Sets the first num bytes of the block of memory pointed by ptr
+///        to the specified value.
+/// @param ptr   Pointer to the block of memory to set.
+/// @param value Value to be set.
+/// @param num   Number of bytes to be set to the given value.
+/// @return The same ptr.
+void *memset(void *ptr, int value, size_t num);
+
+/// @brief Copy the string src into the array dst.
+/// @param dst The destination array where the content is to be copied.
+/// @param src String to be copied.
+/// @return A pointer to dst is returned.
+char *strcpy(char *dst, const char *src);
+
+/// @brief Checks if the two strings are equal.
+/// @param s1 First string to be compared.
+/// @param s2 Second string to be compared.
+/// @return
+/// Returns an integral value indicating the relationship between the strings:
+///     <0 the first character that does not match has a lower
+///        value in s1 than in s2
+///      0 the contents of both strings are equal
+///     >0 the first character that does not match has a greater
+///        value in s1 than in s2
+int strcmp(const char *s1, const char *s2);
+
+/// @brief Returns the length of the string s.
+/// @param s Pointer to the null-terminated byte string to be examined.
+/// @return The length of the null-terminated string str.
+size_t strlen(const char *s);
+
+/// @brief Returns the number of characters inside s, excluding the
+///        terminating null byte ('\0'), but at most count.
+/// @param s Pointer to the null-terminated byte string to be examined.
+/// @param maxlen The upperbound on the length.
+/// @return Returns strlen(s), if that is less than maxlen, or maxlen
+///         if there is no null terminating ('\0') among the first maxlen
+///         characters pointed to by s.
+size_t strnlen(const char *s, size_t maxlen);
+
+/// @brief Removes any whitespace characters from the beginning and end of str.
+/// @param str The string to trim.
+/// @return A pointer to str.
+char *trim(char *str);
+
+/// @brief Separate the given string based on a given delimiter.
+/// @param stringp The string to separate.
+/// @param delim   The delimiter used to separate the string.
+/// @return Returns a pointer to stringp.
+/// @details
+/// Finds the first token in stringp, that is delimited by one of the bytes in
+/// the string delim. This token is terminated by overwriting the delimiter
+/// with a null byte ('\0'), and *stringp is updated to point past the token.
+/// In case no delimiter was found, the token is taken to be the entire string
+/// *stringp, and *stringp is made NULL.
+char *strsep(char **stringp, const char *delim);
+
+/// @brief Move the number "num" into a string.
+/// @param buffer The string containing the number.
+/// @param num    The number to convert.
+/// @param base   The base used to convert.
+/// @return A pointer to buffer.
+char *itoa(char *buffer, unsigned int num, unsigned int base);
+
+/// @brief Replaces the occurrences of find with replace inside str.
+/// @param str     The string to manipulate.
+/// @param find    The character to replace.
+/// @param replace The character used to replace.
+/// @return A pointer to str.
+char *replace_char(char *str, char find, char replace);
+
+/// @brief Converts a file mode (the type and permission information associated
+///        with an inode) into a symbolic string which is stored in the location
+///        referenced by p.
+/// @param mode File mode that encodes access permissions and file type.
+/// @param p    Buffer used to hold the string representation of file mode m.
+void strmode(mode_t mode, char *p);

libc/inc/sys/bitops.h

@@ -0,0 +1,44 @@
+/// @file bitops.h
+/// @brief Bitmasks functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#define bit_set(V, B)          ((V) | (1U << (B)))   ///< Sets the given bit.
+#define bit_clear(V, B)        ((V) & ~(1U << (B)))  ///< Clears the given bit.
+#define bit_flip(V, B)         ((V) ^ (1U << (B)))   ///< Flips the given bit.
+#define bit_set_assign(V, B)   ((V) |= (1U << (B)))  ///< Sets the given bit, permanently.
+#define bit_clear_assign(V, B) ((V) &= ~(1U << (B))) ///< Clears the given bit, permanently.
+#define bit_flip_assign(V, B)  ((V) ^= (1U << (B)))  ///< Flips the given bit, permanently.
+#define bit_check(V, B)        ((V) & (1U << (B)))   ///< Checks if the given bit is 1.
+
+#define bitmask_set(V, M)          ((V) | (M))   ///< Sets the bits identified by the mask.
+#define bitmask_clear(V, M)        ((V) & ~(M))  ///< Clears the bits identified by the mask.
+#define bitmask_flip(V, M)         ((V) ^ (M))   ///< Flips the bits identified by the mask.
+#define bitmask_set_assign(V, M)   ((V) |= (M))  ///< Sets the bits identified by the mask, permanently.
+#define bitmask_clear_assign(V, M) ((V) &= ~(M)) ///< Clears the bits identified by the mask, permanently.
+#define bitmask_flip_assign(V, M)  ((V) ^= (M))  ///< Flips the bits identified by the mask, permanently.
+#define bitmask_check(V, M)        ((V) & (M))   ///< Checks if the bits identified by the mask are all 1.
+
+/// @brief Finds the first bit at zero, starting from the less significative bit.
+/// @param value the value we need to analyze.
+/// @return the position of the first zero bit.
+static inline int find_first_zero(unsigned long value)
+{
+    for (int i = 0; i < 32; ++i)
+        if (!bit_check(value, i))
+            return i;
+    return 0;
+}
+
+/// @brief Finds the first bit not zero, starting from the less significative bit.
+/// @param value the value we need to analyze.
+/// @return the position of the first non-zero bit.
+static inline int find_first_non_zero(unsigned long value)
+{
+    for (int i = 0; i < 32; ++i)
+        if (bit_check(value, i))
+            return i;
+    return 0;
+}

libc/inc/sys/dirent.h

@@ -0,0 +1,50 @@
+/// @file dirent.h
+/// @brief Functions used to manage directories.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "limits.h"
+#include "stddef.h"
+
+/// File types for `d_type'.
+enum {
+    DT_UNKNOWN = 0,
+    DT_FIFO    = 1,
+    DT_CHR     = 2,
+    DT_DIR     = 4,
+    DT_BLK     = 6,
+    DT_REG     = 8,
+    DT_LNK     = 10,
+    DT_SOCK    = 12,
+    DT_WHT     = 14
+};
+
+/// @brief Characters describing the direactory entry.
+static const char dt_char_array[] = {
+    '?', // DT_UNKNOWN = 0,
+    'p', // DT_FIFO = 1,
+    'c', // DT_CHR  = 2,
+    '*',
+    'd', // DT_DIR  = 4,
+    '*',
+    'b', // DT_BLK  = 6,
+    '*',
+    '-', // DT_REG  = 8,
+    '*',
+    'l', // DT_LNK  = 10,
+    '*',
+    's', // DT_SOCK = 12,
+    '*',
+    '?', // DT_WHT  = 14
+};
+
+/// Directory entry.
+typedef struct dirent_t {
+    ino_t d_ino;             ///< Inode number.
+    off_t d_off;             ///< Offset to next linux_dirent.
+    unsigned short d_reclen; ///< Length of this linux_dirent.
+    unsigned short d_type;   ///< type of the directory entry.
+    char d_name[NAME_MAX];   ///< Filename (null-terminated)
+} dirent_t;

libc/inc/sys/errno.h

@@ -0,0 +1,137 @@
+/// @file errno.h
+/// @brief System call errors definition.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+extern int *__geterrno();
+
+/// Provide easy access to the error number.
+#define errno (*__geterrno())
+
+#define EPERM           1 ///< Operation not permitted.
+#define ENOENT          2 ///< No such file or directory.
+#define ESRCH           3 ///< No such process.
+#define EINTR           4 ///< Interrupted system call.
+#define EIO             5 ///< I/O error.
+#define ENXIO           6 ///< No such device or address.
+#define E2BIG           7 ///< Arg list too long.
+#define ENOEXEC         8 ///< Exec format error.
+#define EBADF           9 ///< Bad file number.
+#define ECHILD          10 ///< No child processes.
+#define EAGAIN          11 ///< Try again.
+#define ENOMEM          12 ///< Out of memory.
+#define EACCES          13 ///< Permission denied.
+#define EFAULT          14 ///< Bad address.
+#define ENOTBLK         15 ///< Block device required.
+#define EBUSY           16 ///< Device or resource busy.
+#define EEXIST          17 ///< File exists.
+#define EXDEV           18 ///< Cross-device link.
+#define ENODEV          19 ///< No such device.
+#define ENOTDIR         20 ///< Not a directory.
+#define EISDIR          21 ///< Is a directory.
+#define EINVAL          22 ///< Invalid argument.
+#define ENFILE          23 ///< File table overflow.
+#define EMFILE          24 ///< Too many open files.
+#define ENOTTY          25 ///< Not a typewriter.
+#define ETXTBSY         26 ///< Text file busy.
+#define EFBIG           27 ///< File too large.
+#define ENOSPC          28 ///< No space left on device.
+#define ESPIPE          29 ///< Illegal seek.
+#define EROFS           30 ///< Read-only file system.
+#define EMLINK          31 ///< Too many links.
+#define EPIPE           32 ///< Broken pipe.
+#define EDOM            33 ///< Math argument out of domain of func.
+#define ERANGE          34 ///< Math result not representable.
+#define EDEADLK         35 ///< Resource deadlock would occur.
+#define ENAMETOOLONG    36 ///< File name too long.
+#define ENOLCK          37 ///< No record locks available.
+#define ENOSYS          38 ///< Function not implemented.
+#define ENOTEMPTY       39 ///< Directory not empty.
+#define ELOOP           40 ///< Too many symbolic links encountered.
+#define EWOULDBLOCK     EAGAIN ///< Operation would block.
+#define ENOMSG          42 ///< No message of desired type.
+#define EIDRM           43 ///< Identifier removed.
+#define ECHRNG          44 ///< Channel number out of range.
+#define EL2NSYNC        45 ///< Level 2 not synchronized.
+#define EL3HLT          46 ///< Level 3 halted.
+#define EL3RST          47 ///< Level 3 reset.
+#define ELNRNG          48 ///< Link number out of range.
+#define EUNATCH         49 ///< Protocol driver not attached.
+#define ENOCSI          50 ///< No CSI structure available.
+#define EL2HLT          51 ///< Level 2 halted.
+#define EBADE           52 ///< Invalid exchange.
+#define EBADR           53 ///< Invalid request descriptor.
+#define EXFULL          54 ///< Exchange full.
+#define ENOANO          55 ///< No anode.
+#define EBADRQC         56 ///< Invalid request code.
+#define EBADSLT         57 ///< Invalid slot.
+#define EDEADLOCK       EDEADLK ///< Resource deadlock would occur.
+#define EBFONT          59 ///< Bad font file format.
+#define ENOSTR          60 ///< Device not a stream.
+#define ENODATA         61 ///< No data available.
+#define ETIME           62 ///< Timer expired.
+#define ENOSR           63 ///< Out of streams resources.
+#define ENONET          64 ///< Machine is not on the network.
+#define ENOPKG          65 ///< Package not installed.
+#define EREMOTE         66 ///< Object is remote.
+#define ENOLINK         67 ///< Link has been severed.
+#define EADV            68 ///< Advertise error.
+#define ESRMNT          69 ///< Srmount error.
+#define ECOMM           70 ///< Communication error on send.
+#define EPROTO          71 ///< Protocol error.
+#define EMULTIHOP       72 ///< Multihop attempted.
+#define EDOTDOT         73 ///< RFS specific error.
+#define EBADMSG         74 ///< Not a data message.
+#define EOVERFLOW       75 ///< Value too large for defined data type.
+#define ENOTUNIQ        76 ///< Name not unique on network.
+#define EBADFD          77 ///< File descriptor in bad state.
+#define EREMCHG         78 ///< Remote address changed.
+#define ELIBACC         79 ///< Can not access a needed shared library.
+#define ELIBBAD         80 ///< Accessing a corrupted shared library.
+#define ELIBSCN         81 ///< .lib section in a.out corrupted.
+#define ELIBMAX         82 ///< Attempting to link in too many shared libraries.
+#define ELIBEXEC        83 ///< Cannot exec a shared library directly.
+#define EILSEQ          84 ///< Illegal byte sequence.
+#define ERESTART        85 ///< Interrupted system call should be restarted.
+#define ESTRPIPE        86 ///< Streams pipe error.
+#define EUSERS          87 ///< Too many users.
+#define ENOTSOCK        88 ///< Socket operation on non-socket.
+#define EDESTADDRREQ    89 ///< Destination address required.
+#define EMSGSIZE        90 ///< Message too long.
+#define EPROTOTYPE      91 ///< Protocol wrong type for socket.
+#define ENOPROTOOPT     92 ///< Protocol not available.
+#define EPROTONOSUPPORT 93 ///< Protocol not supported.
+#define ESOCKTNOSUPPORT 94 ///< Socket type not supported.
+#define EOPNOTSUPP      95 ///< Operation not supported on transport endpoint.
+#define EPFNOSUPPORT    96 ///< Protocol family not supported.
+#define EAFNOSUPPORT    97 ///< Address family not supported by protocol.
+#define EADDRINUSE      98 ///< Address already in use.
+#define EADDRNOTAVAIL   99 ///< Cannot assign requested address.
+#define ENETDOWN        100 ///< Network is down.
+#define ENETUNREACH     101 ///< Network is unreachable.
+#define ENETRESET       102 ///< Network dropped connection because of reset.
+#define ECONNABORTED    103 ///< Software caused connection abort.
+#define ECONNRESET      104 ///< Connection reset by peer.
+#define ENOBUFS         105 ///< No buffer space available.
+#define EISCONN         106 ///< Transport endpoint is already connected.
+#define ENOTCONN        107 ///< Transport endpoint is not connected.
+#define ESHUTDOWN       108 ///< Cannot send after transport endpoint shutdown.
+#define ETOOMANYREFS    109 ///< Too many references: cannot splice.
+#define ETIMEDOUT       110 ///< Connection timed out.
+#define ECONNREFUSED    111 ///< Connection refused.
+#define EHOSTDOWN       112 ///< Host is down.
+#define EHOSTUNREACH    113 ///< No route to host.
+#define EALREADY        114 ///< Operation already in progress.
+#define EINPROGRESS     115 ///< Operation now in progress.
+#define ESTALE          116 ///< Stale NFS file handle.
+#define EUCLEAN         117 ///< Structure needs cleaning.
+#define ENOTNAM         118 ///< Not a XENIX named type file.
+#define ENAVAIL         119 ///< No XENIX semaphores available.
+#define EISNAM          120 ///< Is a named type file.
+#define EREMOTEIO       121 ///< Remote I/O error.
+#define EDQUOT          122 ///< Quota exceeded.
+#define ENOMEDIUM       123 ///< No medium found.
+#define EMEDIUMTYPE     124 ///< Wrong medium type.
+#define ENOTSCHEDULABLE 125 ///< The periodc process cannot be scheduled.

libc/inc/sys/ioctl.h

@@ -0,0 +1,14 @@
+/// @file ioctl.h
+/// @brief Input/Output ConTroL (IOCTL) functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Perform the I/O control operation specified by REQUEST on FD.
+///   One argument may follow; its presence and type depend on REQUEST.
+/// @param fd      Must be an open file descriptor.
+/// @param request The device-dependent request code
+/// @param data    An untyped pointer to memory.
+/// @return Return value depends on REQUEST. Usually -1 indicates error.
+int ioctl(int fd, unsigned long int request, void *data);

libc/inc/sys/reboot.h

@@ -0,0 +1,35 @@
+/// @file reboot.h
+/// @brief Defines the values required to issue a reboot.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// Magic values required to use _reboot() system call.
+#define LINUX_REBOOT_MAGIC1 0xfee1dead
+/// Magic values required to use _reboot() system call.
+#define LINUX_REBOOT_MAGIC2 672274793
+/// Magic values required to use _reboot() system call.
+#define LINUX_REBOOT_MAGIC2A 85072278
+/// Magic values required to use _reboot() system call.
+#define LINUX_REBOOT_MAGIC2B 369367448
+/// Magic values required to use _reboot() system call.
+#define LINUX_REBOOT_MAGIC2C 537993216
+
+// Commands accepted by the _reboot() system call.
+/// Restart system using default command and mode.
+#define LINUX_REBOOT_CMD_RESTART 0x01234567
+/// Stop OS and give system control to ROM monitor, if any.
+#define LINUX_REBOOT_CMD_HALT 0xCDEF0123
+/// Ctrl-Alt-Del sequence causes RESTART command.
+#define LINUX_REBOOT_CMD_CAD_ON 0x89ABCDEF
+/// Ctrl-Alt-Del sequence sends SIGINT to init task.
+#define LINUX_REBOOT_CMD_CAD_OFF 0x00000000
+/// Stop OS and remove all power from system, if possible.
+#define LINUX_REBOOT_CMD_POWER_OFF 0x4321FEDC
+/// Restart system using given command string.
+#define LINUX_REBOOT_CMD_RESTART2 0xA1B2C3D4
+/// Suspend system using software suspend if compiled in.
+#define LINUX_REBOOT_CMD_SW_SUSPEND 0xD000FCE2
+/// Restart system using a previously loaded Linux kernel
+#define LINUX_REBOOT_CMD_KEXEC 0x45584543

libc/inc/sys/stat.h

@@ -0,0 +1,42 @@
+/// @file stat.h
+/// @brief Stat functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+#define __SYS_STAT_H
+
+#include "bits/stat.h"
+#include "stddef.h"
+#include "time.h"
+
+/// @brief Retrieves information about the file at the given location.
+/// @param path The path to the file that is being inquired.
+/// @param buf  A structure where data about the file will be stored.
+/// @return Returns a negative value on failure.
+int stat(const char *path, stat_t *buf);
+
+/// @brief Retrieves information about the file at the given location.
+/// @param fd  The file descriptor of the file that is being inquired.
+/// @param buf A structure where data about the file will be stored.
+/// @return Returns a negative value on failure.
+int fstat(int fd, stat_t *buf);
+
+/// @brief Creates a new directory at the given path.
+/// @param path The path of the new directory.
+/// @param mode The permission of the new directory.
+/// @return Returns a negative value on failure.
+int mkdir(const char *path, mode_t mode);
+
+/// @brief Removes the given directory.
+/// @param path The path to the directory to remove.
+/// @return Returns a negative value on failure.
+int rmdir(const char *path);
+
+/// @brief Creates a new file or rewrite an existing one.
+/// @param path path to the file.
+/// @param mode mode for file creation.
+/// @return file descriptor number, -1 otherwise and errno is set to indicate the error.
+/// @details
+/// It is equivalent to: open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)
+int creat(const char *path, mode_t mode);

libc/inc/sys/types.h

@@ -0,0 +1,69 @@
+/// @file types.h
+/// @brief Collection of Kernel datatype
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// The type of process id.
+typedef signed int pid_t;
+
+/// The type of process user variable.
+typedef unsigned int user_t;
+
+/// The type of process status.
+typedef unsigned int status_t;
+
+/// Type for system keys.
+typedef int key_t;
+
+/// Defines the list of flags of a process.
+typedef enum eflags_list {
+    /// Carry flag.
+    EFLAG_CF = (1 << 0),
+
+    /// Parity flag.
+    EFLAG_PF = (1 << 2),
+
+    /// Auxiliary carry flag.
+    EFLAG_AF = (1 << 4),
+
+    /// Zero flag.
+    EFLAG_ZF = (1 << 6),
+
+    /// Sign flag.
+    EFLAG_SF = (1 << 7),
+
+    /// Trap flag.
+    EFLAG_TF = (1 << 8),
+
+    /// Interrupt enable flag.
+    EFLAG_IF = (1 << 9),
+
+    /// Direction flag.
+    EFLAG_DF = (1 << 10),
+
+    /// Overflow flag.
+    EFLAG_OF = (1 << 11),
+
+    /// Nested task flag.
+    EFLAG_NT = (1 << 14),
+
+    ///  Resume flag.
+    EFLAG_RF = (1 << 16),
+
+    /// Virtual 8086 mode flag.
+    EFLAG_VM = (1 << 17),
+
+    /// Alignment check flag (486+).
+    EFLAG_AC = (1 << 18),
+
+    /// Virutal interrupt flag.
+    EFLAG_VIF = (1 << 19),
+
+    /// Virtual interrupt pending flag.
+    EFLAG_VIP = (1 << 20),
+
+    /// ID flag.
+    EFLAG_ID = (1 << 21),
+} eflags_list;

libc/inc/sys/unistd.h

@@ -0,0 +1,249 @@
+/// @file unistd.h
+/// @brief Functions used to manage files.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "sys/types.h"
+#include "sys/dirent.h"
+#include "stddef.h"
+
+#define STDIN_FILENO  0 ///< Standard input.
+#define STDOUT_FILENO 1 ///< Standard output.
+#define STDERR_FILENO 2 ///< Standard error output.
+
+/// @brief        Read data from a file descriptor.
+/// @param fd     The file descriptor.
+/// @param buf    The buffer.
+/// @param nbytes The number of bytes to read.
+/// @return       The number of read characters.
+ssize_t read(int fd, void *buf, size_t nbytes);
+
+/// @brief        Write data into a file descriptor.
+/// @param fd     The file descriptor.
+/// @param buf    The buffer collecting data to written.
+/// @param nbytes The number of bytes to write.
+/// @return       The number of written bytes.
+ssize_t write(int fd, void *buf, size_t nbytes);
+
+/// @brief Opens the file specified by pathname.
+/// @param pathname A pathname for a file.
+/// @param flags file status flags and file access modes of the open file description.
+/// @param mode the file mode bits be applied when a new file is created.
+/// @return file descriptor number, -1 otherwise and errno is set to indicate the error.
+int open(const char *pathname, int flags, mode_t mode);
+
+/// @brief Close a file descriptor.
+/// @param fd The file descriptor.
+/// @return The result of the operation.
+int close(int fd);
+
+/// @brief Repositions the file offset inside a file.
+/// @param fd     The file descriptor of the file.
+/// @param offset The offest to use for the operation.
+/// @param whence The type of operation.
+/// @return  Upon successful completion, returns the resulting offset
+/// location as measured in bytes from the beginning of the file. On
+/// error, the value (off_t) -1 is returned and errno is set to
+/// indicate the error.
+off_t lseek(int fd, off_t offset, int whence);
+
+/// @brief Delete a name and possibly the file it refers to.
+/// @param path The path to the file.
+/// @return
+int unlink(const char *path);
+
+/// @brief Wrapper for exit system call.
+/// @param status The exit status.
+extern void exit(int status);
+
+/// @brief Returns the process ID (PID) of the calling process.
+/// @return pid_t process identifier.
+extern pid_t getpid();
+
+///@brief  Return session id of the given process.
+///        If pid == 0 return the SID of the calling process
+///        If pid != 0 return the SID corresponding to the process having identifier == pid
+///@param pid process identifier from wich we want the SID
+///@return On success return SID of the session
+///        Otherwise return -1 with errno set on: EPERM or ESRCH  
+extern pid_t getsid(pid_t pid);
+
+///@brief creates a new session if the calling process is not a
+///       process group leader.  The calling process is the leader of the
+///       new session (i.e., its session ID is made the same as its process
+///       ID).  The calling process also becomes the process group leader
+///       of a new process group in the session (i.e., its process group ID
+///       is made the same as its process ID).
+///@return On success return SID of the session just created
+///        Otherwise return -1 with errno : EPERM 
+extern pid_t setsid();
+
+///@brief returns the Process Group ID (PGID) of the process specified by pid.
+/// If pid is zero, the process ID of the calling process is used.
+/// @param pid process of which we want to know the PGID.
+/// @return the PGID of the specified process.
+pid_t getpgid(pid_t pid);
+
+/// @brief Sets the Process Group ID (PGID) of the process specified by pid.
+/// If pid is zero, the process ID of the calling process is used.
+/// @param pid process of which we want to set the PGID.
+/// @param pgid the PGID we want to set.
+/// @return returns zero. On error, -1 is returned, and errno is set appropriately.
+int setpgid(pid_t pid, pid_t pgid);
+
+///@brief returns the group ID of the calling process.
+///@return GID of the current process
+extern pid_t getgid();
+
+///@brief sets the effective group ID of the calling process.
+///@param pid process identifier to 
+///@return On success, zero is returned.
+///        Otherwise returns -1 with errno set to :EINVAL or EPERM  
+extern int setgid(pid_t pid);
+
+///@brief Returns the User ID of the calling process.
+///@return User ID of the current process.
+extern uid_t getuid();
+
+///@brief Sets the effective User ID of the calling process.
+///@param uid the new User ID.
+///@return On success, zero is returned.
+///        Otherwise returns -1 with errno set to :EINVAL or EPERM  
+extern int setuid(uid_t uid);
+
+/// @brief Returns the parent process ID (PPID) of the calling process.
+/// @return pid_t parent process identifier.
+extern pid_t getppid();
+
+/// @brief Clone the calling process, but without copying the whole address space.
+///        The calling process is suspended until the new process exits or is
+///        replaced by a call to `execve'.
+/// @return Return -1 for errors, 0 to the new process, and the process ID of
+///         the new process to the old process.
+extern pid_t fork();
+
+/// @brief Replaces the current process image with a new process image (argument list).
+/// @param path The absolute path to the binary file to execute.
+/// @param arg  A list of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param ...  The argument list.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execl(const char *path, const char *arg, ...);
+
+/// @brief Replaces the current process image with a new process image (argument list).
+/// @param file The name of the binary file to execute, which is searched inside the
+///             paths specified inside the PATH environmental variable.
+/// @param arg  A list of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param ...  The argument list.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execlp(const char *file, const char *arg, ...);
+
+/// @brief Replaces the current process image with a new process image (argument list).
+/// @param path The absolute path to the binary file to execute.
+/// @param arg  A list of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param ...  The argument list which contains as last argument the environment.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execle(const char *path, const char *arg, ...);
+
+/// @brief Replaces the current process image with a new process image (argument list).
+/// @param file The name of the binary file to execute, which is searched inside the
+///             paths specified inside the PATH environmental variable.
+/// @param arg  A list of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param ...  The argument list which contains as last argument the environment.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execlpe(const char *file, const char *arg, ...);
+
+/// @brief Replaces the current process image with a new process image (argument vector).
+/// @param path The absolute path to the binary file to execute.
+/// @param argv A vector of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execv(const char *path, char *const argv[]);
+
+/// @brief Replaces the current process image with a new process image (argument vector).
+/// @param file The name of the binary file to execute, which is searched inside the
+///             paths specified inside the PATH environmental variable.
+/// @param argv A vector of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execvp(const char *file, char *const argv[]);
+
+/// @brief Replaces the current process image with a new process
+///        image (argument vector), allows the caller to specify
+///        the environment of the executed program via `envp`.
+/// @param path The absolute path to the binary file to execute.
+/// @param argv A vector of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param envp A vector of one or more pointers to null-terminated strings that represent
+///             the environment list available to the executed program.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execve(const char *path, char *const argv[], char *const envp[]);
+
+/// @brief Replaces the current process image with a new process
+///        image (argument vector), allows the caller to specify
+///        the environment of the executed program via `envp`.
+/// @param file The name of the binary file to execute, which is searched inside the
+///             paths specified inside the PATH environmental variable.
+/// @param argv A vector of one or more pointers to null-terminated strings that represent
+///             the argument list available to the executed program.
+/// @param envp A vector of one or more pointers to null-terminated strings that represent
+///             the environment list available to the executed program.
+/// @return Returns -1 only if an error has occurred, and sets errno.
+int execvpe(const char *file, char *const argv[], char *const envp[]);
+
+/// @brief Adds inc to the nice value for the calling thread.
+/// @param inc The value to add to the nice.
+/// @return On success, the new nice value is returned. On error, -1 is
+///         returned, and errno is set appropriately.
+int nice(int inc);
+
+/// @brief Reboots the system, or enables/disables the reboot keystroke.
+/// @param magic1 fails (with the error EINVAL) unless equals LINUX_REBOOT_MAGIC1.
+/// @param magic2 fails (with the error EINVAL) unless equals LINUX_REBOOT_MAGIC2.
+/// @param cmd The command to send to the reboot.
+/// @param arg Argument passed with some specific commands.
+/// @return For the values of cmd that stop or restart the system, a
+///         successful call to reboot() does not return. For the other cmd
+///         values, zero is returned on success. In all cases, -1 is
+///         returned on failure, and errno is set appropriately.
+int reboot(int magic1, int magic2, unsigned int cmd, void *arg);
+
+/// @brief Get current working directory.
+/// @param buf  The array where the CWD will be copied.
+/// @param size The size of the array.
+/// @return On success, returns the same pointer to buf.
+///         On failure, returnr NULL, and errno is set to indicate the error.
+char *getcwd(char *buf, size_t size);
+
+/// @brief Changes the current working directory to the given path.
+/// @param path The new current working directory.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int chdir(char const *path);
+
+/// @brief Is identical to chdir(), the only difference is that the
+///        directory is given as an open file descriptor.
+/// @param fd The file descriptor of the open directory.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int fchdir(int fd);
+
+/// Provide access to the directory entries.
+/// @param fd The fd pointing to the opened directory.
+/// @param dirp The buffer where de data should be placed.
+/// @param count The size of the buffer.
+/// @return On success, the number of bytes read is returned.  On end of
+///         directory, 0 is returned.  On error, -1 is returned, and errno is set
+///         appropriately.
+int getdents(int fd, dirent_t *dirp, unsigned int count);
+
+/// @brief Send signal to calling thread after desired seconds.
+/// @param seconds the amount of seconds.
+/// @return If there is a previous alarm() request with time remaining, alarm()
+/// shall return a non-zero value that is the number of seconds until the
+/// previous request would have generated a SIGALRM signal. Otherwise, alarm()
+/// shall return 0.
+int alarm(int seconds);

libc/inc/sys/utsname.h

@@ -0,0 +1,29 @@
+/// @file utsname.h
+/// @brief Functions used to provide information about the machine & OS.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// Maximum length of the string used by utsname.
+#define SYS_LEN 257
+
+/// @brief Holds information concerning the machine and the os.
+typedef struct utsname_t {
+    /// The name of the system.
+    char sysname[SYS_LEN];
+    /// The name of the node.
+    char nodename[SYS_LEN];
+    /// Operating system release (e.g., "2.6.28").
+    char release[SYS_LEN];
+    /// The version of the OS.
+    char version[SYS_LEN];
+    /// The name of the machine.
+    char machine[SYS_LEN];
+} utsname_t;
+
+
+/// @brief Returns system information in the structure pointed to by buf.
+/// @param buf Buffer where the info will be placed.
+/// @return 0 on success, a negative value on failure.
+int uname(utsname_t* buf);

libc/inc/sys/wait.h

@@ -1,13 +1,10 @@
-///                MentOS, The Mentoring Operating system project
 /// @file wait.h
-/// @brief
-/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// @brief Event management functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
 /// See LICENSE.md for details.
 
 #pragma once
 
-#include "types.h"
-
 /// @brief Return immediately if no child is there to be waited for.
 #define WNOHANG 0x00000001
 
@@ -43,10 +40,30 @@
 ///        This macro can only be evaluated if WIFSTOPPED() returned nonzero.
 #define WSTOPSIG(status) (WEXITSTATUS(status))
 
+//==== Task States ============================================================
+#define TASK_RUNNING         0x00     ///< The process is either: 1) running on CPU or 2) waiting in a run queue.
+#define TASK_INTERRUPTIBLE   (1 << 0) ///< The process is sleeping, waiting for some event to occur.
+#define TASK_UNINTERRUPTIBLE (1 << 1) ///< Similar to TASK_INTERRUPTIBLE, but it doesn't process signals.
+#define TASK_STOPPED         (1 << 2) ///< Stopped, it's not running, and not able to run.
+#define TASK_TRACED          (1 << 3) ///< Is being monitored by other processes such as debuggers.
+#define EXIT_ZOMBIE          (1 << 4) ///< The process has terminated.
+#define EXIT_DEAD            (1 << 5) ///< The final state.
+//==============================================================================
+
+/// @brief Suspends the execution of the calling thread until ANY child has
+///        changed state.
+/// @param status Variable where the new status of the child is stored.
+/// @return On error, -1 is returned, otherwise it returns the pid of the
+///         child that has unlocked the wait.
 extern pid_t wait(int *status);
 
 /// @brief   Suspends the execution of the calling thread until a child
 ///          specified by pid argument has changed state.
+/// @param pid     Se details below for more information.
+/// @param status  Variable where the new status of the child is stored.
+/// @param options Waitpid options.
+/// @return On error, -1 is returned, otherwise it returns the pid of the
+///         child that has unlocked the wait.
 /// @details
 ///          By default, waitpid() waits only for terminated children, but this
 ///          behavior is modifiable via the options argument, as described below.
@@ -56,5 +73,4 @@ extern pid_t wait(int *status);
 ///               equal to that of the calling process.
 ///        > 0    meaning wait for the child whose process ID is equal to the
 ///               value of pid.
-/// @return On error, -1 is returned.
 extern pid_t waitpid(pid_t pid, int *status, int options);

libc/inc/system/syscall_types.h

@@ -0,0 +1,307 @@
+/// @file syscall_types.h
+/// @brief System Call numbers.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#define __NR_exit                   1   ///< System-call number for `exit`
+#define __NR_fork                   2   ///< System-call number for `fork`
+#define __NR_read                   3   ///< System-call number for `read`
+#define __NR_write                  4   ///< System-call number for `write`
+#define __NR_open                   5   ///< System-call number for `open`
+#define __NR_close                  6   ///< System-call number for `close`
+#define __NR_waitpid                7   ///< System-call number for `waitpid`
+#define __NR_creat                  8   ///< System-call number for `creat`
+#define __NR_link                   9   ///< System-call number for `link`
+#define __NR_unlink                 10  ///< System-call number for `unlink`
+#define __NR_execve                 11  ///< System-call number for `execve`
+#define __NR_chdir                  12  ///< System-call number for `chdir`
+#define __NR_time                   13  ///< System-call number for `time`
+#define __NR_mknod                  14  ///< System-call number for `mknod`
+#define __NR_chmod                  15  ///< System-call number for `chmod`
+#define __NR_lchown                 16  ///< System-call number for `lchown`
+#define __NR_stat                   18  ///< System-call number for `stat`
+#define __NR_lseek                  19  ///< System-call number for `lseek`
+#define __NR_getpid                 20  ///< System-call number for `getpid`
+#define __NR_mount                  21  ///< System-call number for `mount`
+#define __NR_oldumount              22  ///< System-call number for `oldumount`
+#define __NR_setuid                 23  ///< System-call number for `setuid`
+#define __NR_getuid                 24  ///< System-call number for `getuid`
+#define __NR_stime                  25  ///< System-call number for `stime`
+#define __NR_ptrace                 26  ///< System-call number for `ptrace`
+#define __NR_alarm                  27  ///< System-call number for `alarm`
+#define __NR_fstat                  28  ///< System-call number for `fstat`
+#define __NR_pause                  29  ///< System-call number for `pause`
+#define __NR_utime                  30  ///< System-call number for `utime`
+#define __NR_access                 33  ///< System-call number for `access`
+#define __NR_nice                   34  ///< System-call number for `nice`
+#define __NR_sync                   36  ///< System-call number for `sync`
+#define __NR_kill                   37  ///< System-call number for `kill`
+#define __NR_rename                 38  ///< System-call number for `rename`
+#define __NR_mkdir                  39  ///< System-call number for `mkdir`
+#define __NR_rmdir                  40  ///< System-call number for `rmdir`
+#define __NR_dup                    41  ///< System-call number for `dup`
+#define __NR_pipe                   42  ///< System-call number for `pipe`
+#define __NR_times                  43  ///< System-call number for `times`
+#define __NR_brk                    45  ///< System-call number for `brk`
+#define __NR_setgid                 46  ///< System-call number for `setgid`
+#define __NR_getgid                 47  ///< System-call number for `getgid`
+#define __NR_signal                 48  ///< System-call number for `signal`
+#define __NR_geteuid                49  ///< System-call number for `geteuid`
+#define __NR_getegid                50  ///< System-call number for `getegid`
+#define __NR_acct                   51  ///< System-call number for `acct`
+#define __NR_umount                 52  ///< System-call number for `umount`
+#define __NR_ioctl                  54  ///< System-call number for `ioctl`
+#define __NR_fcntl                  55  ///< System-call number for `fcntl`
+#define __NR_setpgid                57  ///< System-call number for `setpgid`
+#define __NR_olduname               59  ///< System-call number for `olduname`
+#define __NR_umask                  60  ///< System-call number for `umask`
+#define __NR_chroot                 61  ///< System-call number for `chroot`
+#define __NR_ustat                  62  ///< System-call number for `ustat`
+#define __NR_dup2                   63  ///< System-call number for `dup2`
+#define __NR_getppid                64  ///< System-call number for `getppid`
+#define __NR_getpgrp                65  ///< System-call number for `getpgrp`
+#define __NR_setsid                 66  ///< System-call number for `setsid`
+#define __NR_sigaction              67  ///< System-call number for `sigaction`
+#define __NR_sgetmask               68  ///< System-call number for `sgetmask`
+#define __NR_ssetmask               69  ///< System-call number for `ssetmask`
+#define __NR_setreuid               70  ///< System-call number for `setreuid`
+#define __NR_setregid               71  ///< System-call number for `setregid`
+#define __NR_sigsuspend             72  ///< System-call number for `sigsuspend`
+#define __NR_sigpending             73  ///< System-call number for `sigpending`
+#define __NR_sethostname            74  ///< System-call number for `sethostname`
+#define __NR_setrlimit              75  ///< System-call number for `setrlimit`
+#define __NR_getrlimit              76  ///< System-call number for `getrlimit`
+#define __NR_getrusage              77  ///< System-call number for `getrusage`
+#define __NR_gettimeofday           78  ///< System-call number for `gettimeofday`
+#define __NR_settimeofday           79  ///< System-call number for `settimeofday`
+#define __NR_getgroups              80  ///< System-call number for `getgroups`
+#define __NR_setgroups              81  ///< System-call number for `setgroups`
+#define __NR_symlink                83  ///< System-call number for `symlink`
+#define __NR_lstat                  84  ///< System-call number for `lstat`
+#define __NR_readlink               85  ///< System-call number for `readlink`
+#define __NR_uselib                 86  ///< System-call number for `uselib`
+#define __NR_swapon                 87  ///< System-call number for `swapon`
+#define __NR_reboot                 88  ///< System-call number for `reboot`
+#define __NR_readdir                89  ///< System-call number for `readdir`
+#define __NR_mmap                   90  ///< System-call number for `mmap`
+#define __NR_munmap                 91  ///< System-call number for `munmap`
+#define __NR_truncate               92  ///< System-call number for `truncate`
+#define __NR_ftruncate              93  ///< System-call number for `ftruncate`
+#define __NR_fchmod                 94  ///< System-call number for `fchmod`
+#define __NR_fchown                 95  ///< System-call number for `fchown`
+#define __NR_getpriority            96  ///< System-call number for `getpriority`
+#define __NR_setpriority            97  ///< System-call number for `setpriority`
+#define __NR_statfs                 99  ///< System-call number for `statfs`
+#define __NR_fstatfs                100 ///< System-call number for `fstatfs`
+#define __NR_ioperm                 101 ///< System-call number for `ioperm`
+#define __NR_socketcall             102 ///< System-call number for `socketcall`
+#define __NR_syslog                 103 ///< System-call number for `syslog`
+#define __NR_setitimer              104 ///< System-call number for `setitimer`
+#define __NR_getitimer              105 ///< System-call number for `getitimer`
+#define __NR_newstat                106 ///< System-call number for `newstat`
+#define __NR_newlstat               107 ///< System-call number for `newlstat`
+#define __NR_newfstat               108 ///< System-call number for `newfstat`
+#define __NR_uname                  109 ///< System-call number for `uname`
+#define __NR_iopl                   110 ///< System-call number for `iopl`
+#define __NR_vhangup                111 ///< System-call number for `vhangup`
+#define __NR_idle                   112 ///< System-call number for `idle`
+#define __NR_vm86old                113 ///< System-call number for `vm86old`
+#define __NR_wait4                  114 ///< System-call number for `wait4`
+#define __NR_swapoff                115 ///< System-call number for `swapoff`
+#define __NR_sysinfo                116 ///< System-call number for `sysinfo`
+#define __NR_ipc                    117 ///< System-call number for `ipc`
+#define __NR_fsync                  118 ///< System-call number for `fsync`
+#define __NR_sigreturn              119 ///< System-call number for `sigreturn`
+#define __NR_clone                  120 ///< System-call number for `clone`
+#define __NR_setdomainname          121 ///< System-call number for `setdomainname`
+#define __NR_newuname               122 ///< System-call number for `newuname`
+#define __NR_modify_ldt             123 ///< System-call number for `modify_ldt`
+#define __NR_adjtimex               124 ///< System-call number for `adjtimex`
+#define __NR_mprotect               125 ///< System-call number for `mprotect`
+#define __NR_sigprocmask            126 ///< System-call number for `sigprocmask`
+#define __NR_create_module          127 ///< System-call number for `create_module`
+#define __NR_init_module            128 ///< System-call number for `init_module`
+#define __NR_delete_module          129 ///< System-call number for `delete_module`
+#define __NR_get_kernel_syms        130 ///< System-call number for `get_kernel_syms`
+#define __NR_quotactl               131 ///< System-call number for `quotactl`
+#define __NR_getpgid                132 ///< System-call number for `getpgid`
+#define __NR_fchdir                 133 ///< System-call number for `fchdir`
+#define __NR_bdflush                134 ///< System-call number for `bdflush`
+#define __NR_sysfs                  135 ///< System-call number for `sysfs`
+#define __NR_personality            136 ///< System-call number for `personality`
+#define __NR_setfsuid               138 ///< System-call number for `setfsuid`
+#define __NR_setfsgid               139 ///< System-call number for `setfsgid`
+#define __NR_llseek                 140 ///< System-call number for `llseek`
+#define __NR_getdents               141 ///< System-call number for `getdents`
+#define __NR_select                 142 ///< System-call number for `select`
+#define __NR_flock                  143 ///< System-call number for `flock`
+#define __NR_msync                  144 ///< System-call number for `msync`
+#define __NR_readv                  145 ///< System-call number for `readv`
+#define __NR_writev                 146 ///< System-call number for `writev`
+#define __NR_getsid                 147 ///< System-call number for `getsid`
+#define __NR_fdatasync              148 ///< System-call number for `fdatasync`
+#define __NR_sysctl                 149 ///< System-call number for `sysctl`
+#define __NR_mlock                  150 ///< System-call number for `mlock`
+#define __NR_munlock                151 ///< System-call number for `munlock`
+#define __NR_mlockall               152 ///< System-call number for `mlockall`
+#define __NR_munlockall             153 ///< System-call number for `munlockall`
+#define __NR_sched_setparam         154 ///< System-call number for `sched_setparam`
+#define __NR_sched_getparam         155 ///< System-call number for `sched_getparam`
+#define __NR_sched_setscheduler     156 ///< System-call number for `sched_setscheduler`
+#define __NR_sched_getscheduler     157 ///< System-call number for `sched_getscheduler`
+#define __NR_sched_yield            158 ///< System-call number for `sched_yield`
+#define __NR_sched_get_priority_max 159 ///< System-call number for `sched_get_priority_max`
+#define __NR_sched_get_priority_min 160 ///< System-call number for `sched_get_priority_min`
+#define __NR_sched_rr_get_interval  161 ///< System-call number for `sched_rr_get_interval`
+#define __NR_nanosleep              162 ///< System-call number for `nanosleep`
+#define __NR_mremap                 163 ///< System-call number for `mremap`
+#define __NR_setresuid              164 ///< System-call number for `setresuid`
+#define __NR_getresuid              165 ///< System-call number for `getresuid`
+#define __NR_vm86                   166 ///< System-call number for `vm86`
+#define __NR_query_module           167 ///< System-call number for `query_module`
+#define __NR_poll                   168 ///< System-call number for `poll`
+#define __NR_nfsservctl             169 ///< System-call number for `nfsservctl`
+#define __NR_setresgid              170 ///< System-call number for `setresgid`
+#define __NR_getresgid              171 ///< System-call number for `getresgid`
+#define __NR_prctl                  172 ///< System-call number for `prctl`
+#define __NR_rt_sigreturn           173 ///< System-call number for `rt_sigreturn`
+#define __NR_rt_sigaction           174 ///< System-call number for `rt_sigaction`
+#define __NR_rt_sigprocmask         175 ///< System-call number for `rt_sigprocmask`
+#define __NR_rt_sigpending          176 ///< System-call number for `rt_sigpending`
+#define __NR_rt_sigtimedwait        177 ///< System-call number for `rt_sigtimedwait`
+#define __NR_rt_sigqueueinfo        178 ///< System-call number for `rt_sigqueueinfo`
+#define __NR_rt_sigsuspend          179 ///< System-call number for `rt_sigsuspend`
+#define __NR_pread                  180 ///< System-call number for `pread`
+#define __NR_pwrite                 181 ///< System-call number for `pwrite`
+#define __NR_chown                  182 ///< System-call number for `chown`
+#define __NR_getcwd                 183 ///< System-call number for `getcwd`
+#define __NR_capget                 184 ///< System-call number for `capget`
+#define __NR_capset                 185 ///< System-call number for `capset`
+#define __NR_sigaltstack            186 ///< System-call number for `sigaltstack`
+#define __NR_sendfile               187 ///< System-call number for `sendfile`
+#define __NR_waitperiod             188 ///< System-call number for `waitperiod`
+#define __NR_msgctl                 189 ///<  System-call number for `msgctl`
+#define __NR_msgget                 190 ///<  System-call number for `msgget`
+#define __NR_msgrcv                 191 ///<  System-call number for `msgrcv`
+#define __NR_msgsnd                 192 ///<  System-call number for `msgsnd`
+#define __NR_semctl                 193 ///<  System-call number for `semctl`
+#define __NR_semget                 194 ///<  System-call number for `semget`
+#define __NR_semop                  195 ///<  System-call number for `semop`
+#define __NR_shmat                  196 ///<  System-call number for `shmat`
+#define __NR_shmctl                 197 ///<  System-call number for `shmctl`
+#define __NR_shmdt                  198 ///<  System-call number for `shmdt`
+#define __NR_shmget                 199 ///<  System-call number for `shmget`
+#define SYSCALL_NUMBER              200 ///< The total number of system-calls.
+
+/// @brief Handle the value returned from a system call.
+/// @param type Specifies the type of the returned value.
+/// @param res  The name of the variable where the result of the SC is stored.
+#define __syscall_return(type, res)                        \
+    do {                                                   \
+        if ((unsigned int)(res) >= (unsigned int)(-125)) { \
+            errno = -(res);                                \
+            (res) = -1;                                    \
+        }                                                  \
+        return (type)(res);                                \
+    } while (0)
+
+/// @brief Heart of the code that calls a system call with 0 parameters.
+#define __inline_syscall0(res, name) \
+    __asm__ __volatile__("int $0x80" \
+                         : "=a"(res) \
+                         : "0"(__NR_##name))
+
+/// @brief Heart of the code that calls a system call with 1 parameter.
+#define __inline_syscall1(res, name, arg1)                                    \
+    __asm__ __volatile__("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx" \
+                         : "=a"(res)                                          \
+                         : "0"(__NR_##name), "ri"((int)(arg1))                \
+                         : "memory");
+
+/// @brief Heart of the code that calls a system call with 2 parameters.
+#define __inline_syscall2(res, name, arg1, arg2)                                 \
+    __asm__ __volatile__("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"    \
+                         : "=a"(res)                                             \
+                         : "0"(__NR_##name), "ri"((int)(arg1)), "c"((int)(arg2)) \
+                         : "memory");
+
+/// @brief Heart of the code that calls a system call with 3 parameters.
+#define __inline_syscall3(res, name, arg1, arg2, arg3)                            \
+    __asm__ __volatile__("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"     \
+                         : "=a"(res)                                              \
+                         : "0"(__NR_##name), "ri"((int)(arg1)), "c"((int)(arg2)), \
+                           "d"((int)(arg3))                                       \
+                         : "memory");
+
+/// @brief Heart of the code that calls a system call with 4 parameters.
+#define __inline_syscall4(res, name, arg1, arg2, arg3, arg4)                      \
+    __asm__ __volatile__("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"     \
+                         : "=a"(res)                                              \
+                         : "0"(__NR_##name), "ri"((int)(arg1)), "c"((int)(arg2)), \
+                           "d"((int)(arg3)), "S"((int)(arg4))                     \
+                         : "memory");
+
+/// @brief Heart of the code that calls a system call with 5 parameters.
+#define __inline_syscall5(res, name, arg1, arg2, arg3, arg4, arg5)                \
+    __asm__ __volatile__("push %%ebx ; movl %2,%%ebx ; movl %1,%%eax ; "          \
+                         "int $0x80 ; pop %%ebx"                                  \
+                         : "=a"(res)                                              \
+                         : "i"(__NR_##name), "ri"((int)(arg1)), "c"((int)(arg2)), \
+                           "d"((int)(arg3)), "S"((int)(arg4)), "D"((int)(arg5))   \
+                         : "memory");
+
+/// @brief System call with 0 parameters.
+#define _syscall0(type, name)           \
+    type name(void)                     \
+    {                                   \
+        long __res;                     \
+        __inline_syscall0(__res, name); \
+        __syscall_return(type, __res);  \
+    }
+
+/// @brief System call with 1 parameter.
+#define _syscall1(type, name, type1, arg1)    \
+    type name(type1 arg1)                     \
+    {                                         \
+        long __res;                           \
+        __inline_syscall1(__res, name, arg1); \
+        __syscall_return(type, __res);        \
+    }
+
+/// @brief System call with 2 parameters.
+#define _syscall2(type, name, type1, arg1, type2, arg2) \
+    type name(type1 arg1, type2 arg2)                   \
+    {                                                   \
+        long __res;                                     \
+        __inline_syscall2(__res, name, arg1, arg2);     \
+        __syscall_return(type, __res);                  \
+    }
+
+/// @brief System call with 3 parameters.
+#define _syscall3(type, name, type1, arg1, type2, arg2, type3, arg3) \
+    type name(type1 arg1, type2 arg2, type3 arg3)                    \
+    {                                                                \
+        long __res;                                                  \
+        __inline_syscall3(__res, name, arg1, arg2, arg3);            \
+        __syscall_return(type, __res);                               \
+    }
+
+/// @brief System call with 4 parameters.
+#define _syscall4(type, name, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
+    type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4)                     \
+    {                                                                             \
+        long __res;                                                               \
+        __inline_syscall4(__res, name, arg1, arg2, arg3, arg4);                   \
+        __syscall_return(type, __res);                                            \
+    }
+
+/// @brief System call with 5 parameters.
+#define _syscall5(type, name, type1, arg1, type2, arg2, type3, arg3, type4, arg4, type5, arg5) \
+    type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5)                      \
+    {                                                                                          \
+        long __res;                                                                            \
+        __inline_syscall5(__res, name, arg1, arg2, arg3, arg4, arg5);                          \
+        __syscall_return(type, __res);                                                         \
+    }

libc/inc/termios.h

@@ -0,0 +1,21 @@
+/// @file termios.h
+/// @brief Defines the termios functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "bits/termios-struct.h"
+
+/// @brief Put the state of FD into *TERMIOS_P.
+/// @param fd
+/// @param termios_p
+/// @return
+extern int tcgetattr(int fd, termios_t *termios_p);
+
+/// @brief Set the state of FD to *TERMIOS_P.
+/// @param fd
+/// @param optional_actions
+/// @param termios_p
+/// @return
+extern int tcsetattr(int fd, int optional_actions, const termios_t *termios_p);

libc/inc/time.h

@@ -0,0 +1,124 @@
+/// @file time.h
+/// @brief Time-related functions.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// @brief This timer counts down in real (i.e., wall clock) time. At each
+/// expiration, a SIGALRM signal is generated.
+#define ITIMER_REAL 0
+/// @brief This timer counts down against the user-mode CPU time consumed by the
+/// process. At each expiration, a SIGVTALRM signal is generated.
+#define ITIMER_VIRTUAL 1
+/// @brief This timer counts down against the total (i.e., both user and system)
+/// CPU time consumed by the process. At each expiration, a SIGPROF signal is
+/// generated.
+#define ITIMER_PROF 2
+
+/// Used to store time values.
+typedef unsigned int time_t;
+
+/// Used to get information about the current time.
+typedef struct tm_t {
+    /// Seconds [0 to 59]
+    int tm_sec;
+    /// Minutes [0 to 59]
+    int tm_min;
+    /// Hours [0 to 23]
+    int tm_hour;
+    /// Day of the month [1 to 31]
+    int tm_mday;
+    /// Month [0 to 11]
+    int tm_mon;
+    /// Year [since 1900]
+    int tm_year;
+    /// Day of the week [0 to 6]
+    int tm_wday;
+    /// Day in the year [0 to 365]
+    int tm_yday;
+    /// Is Daylight Saving Time.
+    int tm_isdst;
+} tm_t;
+
+/// Rappresents time.
+typedef struct _timeval {
+    time_t tv_sec;  ///< Seconds.
+    time_t tv_usec; ///< Microseconds.
+} timeval;
+
+/// Rappresents a time interval.
+typedef struct _itimerval {
+    timeval it_interval; ///< Next value.
+    timeval it_value;    ///< Current value.
+} itimerval;
+
+/// @brief Specify intervals of time with nanosecond precision.
+typedef struct timespec {
+    time_t tv_sec; ///< Seconds.
+    long tv_nsec;  ///< Nanoseconds.
+} timespec;
+
+/// @brief Returns the current time.
+/// @param t Where the time should be stored.
+/// @return The current time.
+time_t time(time_t *t);
+
+/// @brief Return the difference between the two time values.
+/// @param time1 The first time value.
+/// @param time2 The second time value.
+/// @return The difference in terms of seconds.
+time_t difftime(time_t time1, time_t time2);
+
+/// @brief The current time broken down into a tm_t structure.
+/// @param timep A pointer to a variable holding the current time.
+/// @return The time broken down.
+tm_t *localtime(const time_t *timep);
+
+/// @brief Formats the time tm according to the format specification format
+///        and places the result in the character array s of size max.
+/// @param s      The destination buffer.
+/// @param max    The maximum length of the buffer.
+/// @param format The buffer used to generate the time.
+/// @param tm     The broken-down time.
+/// @return The number of bytes (excluding the terminating null) placed in s.
+size_t strftime(char *s, size_t max, const char *format, const tm_t *tm);
+
+/// @brief Suspends the execution of the calling thread.
+/// @param req The amount of time we want to sleep.
+/// @param rem The remaining time we did not sleep.
+/// @return If the call is interrupted by a signal handler, nanosleep()
+///         returns -1, sets errno to EINTR, and writes the remaining time
+///         into the structure pointed to by rem unless rem is NULL.
+/// @details
+/// The execution is suspended until either at least the time specified
+/// in *req has elapsed, or the delivery of a signal that triggers the
+/// invocation of a handler in the calling thread or that terminates
+/// the process.
+int nanosleep(const timespec *req, timespec *rem);
+
+/// @brief Causes the calling thread to sleep either until the number of
+///        real-time seconds specified in seconds have elapsed or
+///        until a signal arrives which is not ignored.
+/// @param seconds The number of seconds we want to sleep.
+/// @return Zero if the requested time has elapsed, or the number of seconds
+///         left to sleep, if the call was interrupted by a signal handler.
+unsigned int sleep(unsigned int seconds);
+
+/// @brief Fills the structure pointed to by curr_value with the current setting
+/// for the timer specified by which.
+/// @param which which timer.
+/// @param curr_value where we place the timer value.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int getitimer(int which, itimerval *curr_value);
+
+/// @brief The system provides each process with three interval timers, each
+/// decrementing in a distinct time domain. When any timer expires, a signal is
+/// sent to the process, and the timer (potentially) restarts.
+/// @param which which timer.
+/// @param new_value the new value for the timer.
+/// @param old_value output variable where the function places the previous value.
+/// @return 0 on success, -1 on failure and errno is set to indicate the error.
+int setitimer(int which, const itimerval *new_value, itimerval *old_value);

libc/src/abort.c

@@ -0,0 +1,80 @@
+/// @file abort.c
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "sys/unistd.h"
+#include "string.h"
+#include "signal.h"
+#include "stdio.h"
+
+/// @brief Since there could be signal handlers listening for the abort, we need
+/// to keep track at which stage of the abort we are.
+static int stage = 0;
+
+void abort(void)
+{
+    sigaction_t action;
+    sigset_t sigset;
+
+    /* Unblock SIGABRT.  */
+    if (stage == 0) {
+        ++stage;
+
+        sigemptyset(&sigset);
+        sigaddset(&sigset, SIGABRT);
+        sigprocmask(SIG_UNBLOCK, &sigset, 0);
+    }
+
+    /* Send signal which possibly calls a user handler.  */
+    if (stage == 1) {
+
+        // We must allow recursive calls of abort
+        int save_stage = stage;
+
+        stage = 0;
+        kill(getpid(), SIGABRT);
+        stage = save_stage + 1;
+    }
+
+    /* There was a handler installed.  Now remove it.  */
+    if (stage == 2) {
+        ++stage;
+
+        memset(&action, 0, sizeof(action));
+
+        action.sa_handler = SIG_DFL;
+        sigemptyset(&action.sa_mask);
+        action.sa_flags = 0;
+
+        sigaction(SIGABRT, &action, NULL);
+    }
+
+    /* Try again.  */
+    if (stage == 3) {
+        ++stage;
+
+        kill(getpid(), SIGABRT);
+    }
+
+    /* Now try to abort using the system specific command.  */
+    if (stage == 4) {
+        ++stage;
+
+        __asm__ __volatile__("hlt");
+    }
+
+    /* If we can't signal ourselves and the abort instruction failed, exit.  */
+    if (stage == 5) {
+        ++stage;
+
+        exit(127);
+    }
+
+    // If even this fails try to use the provided instruction to crash
+    //  or otherwise make sure we never return.
+#pragma clang diagnostic push
+#pragma ide diagnostic ignored "EndlessLoop"
+    while (1) __asm__ __volatile__("hlt");
+#pragma clang diagnostic pop
+}

libc/src/assert.c

@@ -0,0 +1,18 @@
+/// @file assert.c
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "assert.h"
+#include "stdlib.h"
+#include "stdio.h"
+
+void __assert_fail(const char *assertion, const char *file, const char *function, unsigned int line)
+{
+    printf("FILE: %s\n"
+           "FUNC: %s\n"
+           "LINE: %d\n\n"
+           "Assertion `%s` failed.\n",
+           file, (function ? function : "NO_FUN"), line, assertion);
+    abort();
+}

libc/src/crt0.S

@@ -0,0 +1,15 @@
+extern main
+extern __libc_start_main
+global _start
+
+; -----------------------------------------------------------------------------
+; SECTION (text)
+; -----------------------------------------------------------------------------
+section .text
+_start:                     ; _start is the entry point known to the linker
+    mov ebp, 0              ; Set ebp to 0 as x86 programs require
+    push main               ; Push the pointer to `main` to the stack.
+    call __libc_start_main  ; Call the libc initialization function.
+    mov ebx, eax            ; Move `main` return value to ebx.
+    mov eax, 1              ; Call the `exit` function by using `int 80` (i.e., a system call)
+    int 0x80

libc/src/ctype.c

@@ -0,0 +1,67 @@
+/// @file ctype.c
+/// @brief Functions related to character handling.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "ctype.h"
+
+/// Distance from a uppercase character to the correspondent lowercase in ASCII.
+#define OFFSET 32
+
+int isdigit(int c)
+{
+    return (c >= 48 && c <= 57);
+}
+
+int isalpha(int c)
+{
+    return ((c >= 65 && c <= 90) || (c >= 97 && c <= 122));
+}
+
+int iscntrl(int c)
+{
+    return ((c >= 0x00 && c <= 0x1F) || (c == 0x7F));
+}
+
+int isalnum(int c)
+{
+    return (isalpha(c) || isdigit(c));
+}
+
+int isxdigit(int c)
+{
+    return (isdigit(c) || (c >= 65 && c <= 70));
+}
+
+int islower(int c)
+{
+    return (c >= 97 && c <= 122);
+}
+
+int isupper(int c)
+{
+    return (c >= 65 && c <= 90);
+}
+
+int tolower(int c)
+{
+    if (isalpha(c) == 0 || islower(c)) {
+        return c;
+    }
+
+    return c + OFFSET;
+}
+
+int toupper(int c)
+{
+    if (isalpha(c) == 0 || isupper(c)) {
+        return c;
+    }
+
+    return c - OFFSET;
+}
+
+int isspace(int c)
+{
+    return (c == ' ');
+}

libc/src/debug.c

@@ -0,0 +1,108 @@
+/// @file   debug.c
+/// @brief  Debugging primitives.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include <debug.h>
+
+#include <stddef.h>
+#include <io/port_io.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/bitops.h>
+#include <math.h>
+
+/// Serial port for QEMU.
+#define SERIAL_COM1 (0x03F8)
+
+#define FG_RESET "\033[0m" ///< ANSI code for resetting.
+
+void dbg_putchar(char c)
+{
+    outportb(SERIAL_COM1, (uint8_t)c);
+}
+
+void dbg_puts(const char *s)
+{
+    while ((*s) != 0)
+        dbg_putchar(*s++);
+}
+
+static inline void __debug_print_header(const char *file, const char *fun, int line)
+{
+    static char tmp_prefix[BUFSIZ], final_prefix[BUFSIZ];
+    dbg_puts(FG_RESET);
+    dbg_puts("[ LB |");
+    sprintf(tmp_prefix, "%s:%d", file, line);
+    sprintf(final_prefix, " %-20s ", tmp_prefix);
+    dbg_puts(final_prefix);
+#if 0
+    dbg_putchar('|');
+    sprintf(final_prefix, " %-25s ]", fun);
+    dbg_puts(final_prefix);
+#else
+    dbg_putchar(']');
+#endif
+}
+
+void dbg_printf(const char *file, const char *fun, int line, const char *format, ...)
+{
+    // Define a buffer for the formatted string.
+    static char formatted[BUFSIZ];
+    static short new_line = 1;
+
+    // Stage 1: FORMAT
+    if (strlen(format) >= BUFSIZ)
+        return;
+
+    // Start variabile argument's list.
+    va_list ap;
+    va_start(ap, format);
+    // Format the message.
+    vsprintf(formatted, format, ap);
+    // End the list of arguments.
+    va_end(ap);
+
+    // Stage 2: SEND
+    if (new_line) {
+        __debug_print_header(file, fun, line);
+        new_line = 0;
+    }
+    for (size_t it = 0; (formatted[it] != 0) && (it < BUFSIZ); ++it) {
+        dbg_putchar(formatted[it]);
+        if (formatted[it] != '\n') {
+            continue;
+        }
+        if ((it + 1) >= BUFSIZ) {
+            continue;
+        }
+        if (formatted[it + 1] == 0) {
+            new_line = 1;
+        } else {
+            __debug_print_header(file, fun, line);
+        }
+    }
+}
+
+const char *to_human_size(unsigned long bytes)
+{
+    static char output[200];
+    const char *suffix[] = { "B", "KB", "MB", "GB", "TB" };
+    char length          = sizeof(suffix) / sizeof(suffix[0]);
+    int i                = 0;
+    double dblBytes      = bytes;
+    if (bytes > 1024) {
+        for (i = 0; (bytes / 1024) > 0 && i < length - 1; i++, bytes /= 1024)
+            dblBytes = bytes / 1024.0;
+    }
+    sprintf(output, "%.03lf %2s", dblBytes, suffix[i]);
+    return output;
+}
+
+const char *dec_to_binary(unsigned long value, unsigned length)
+{
+    static char buffer[33];
+    for (int i = 0, j = 32 - min(max(0, length), 32); j < 32; ++i, ++j)
+        buffer[i] = bit_check(value, 31 - j) ? '1' : '0';
+    return buffer;
+}

libc/src/fcvt.c

@@ -0,0 +1,103 @@
+/// @file fcvt.c
+/// @brief Define the functions required to turn double values into a string.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "fcvt.h"
+#include "math.h"
+
+static void cvt(double arg, int ndigits, int *decpt, int *sign, char *buf, unsigned buf_size, int eflag)
+{
+    int r2;
+    double fi, fj;
+    char *p, *p1;
+
+    char *buf_end = (buf + buf_size);
+
+    if (ndigits < 0) {
+        ndigits = 0;
+    }
+
+    if (ndigits >= buf_size - 1) {
+        ndigits = buf_size - 2;
+    }
+
+    r2    = 0;
+    *sign = 0;
+    p     = &buf[0];
+
+    if (arg < 0) {
+        *sign = 1;
+        arg   = -arg;
+    }
+
+    arg = modf(arg, &fi);
+    p1  = buf_end;
+
+    if (fi != 0) {
+        p1 = buf_end;
+        while (fi != 0) {
+            fj    = modf(fi / 10, &fi);
+            *--p1 = (int)((fj + .03) * 10) + '0';
+            r2++;
+        }
+        while (p1 < buf_end) {
+            *p++ = *p1++;
+        }
+    } else if (arg > 0) {
+        while ((fj = arg * 10) < 1) {
+            arg = fj;
+            r2--;
+        }
+    }
+
+    p1 = &buf[ndigits];
+    if (eflag == 0) {
+        p1 += r2;
+    }
+
+    *decpt = r2;
+    if (p1 < &buf[0]) {
+        buf[0] = '\0';
+        return;
+    }
+
+    while (p <= p1 && p < buf_end) {
+        arg *= 10;
+        arg  = modf(arg, &fj);
+        *p++ = (int)fj + '0';
+    }
+
+    if (p1 >= buf_end) {
+        buf[buf_size - 1] = '\0';
+        return;
+    }
+
+    p = p1;
+    *p1 += 5;
+    while (*p1 > '9') {
+        *p1 = '0';
+        if (p1 > buf) {
+            ++*--p1;
+        } else {
+            *p1 = '1';
+            (*decpt)++;
+            if (eflag == 0) {
+                if (p > buf)
+                    *p = '0';
+                p++;
+            }
+        }
+    }
+    *p = '\0';
+}
+
+void ecvtbuf(double arg, int chars, int *decpt, int *sign, char *buf, unsigned buf_size)
+{
+    cvt(arg, chars, decpt, sign, buf, buf_size, 1);
+}
+
+void fcvtbuf(double arg, int decimals, int *decpt, int *sign, char *buf, unsigned buf_size)
+{
+    cvt(arg, decimals, decpt, sign, buf, buf_size, 0);
+}

libc/src/grp.c

@@ -0,0 +1,238 @@
+/// @file grp.c
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "grp.h"
+#include "sys/unistd.h"
+#include "sys/errno.h"
+#include "assert.h"
+#include "string.h"
+#include "stdio.h"
+#include "debug.h"
+#include "fcntl.h"
+
+static int __fd = -1;
+
+/// @brief It parses the line (as string) and saves its content inside the
+/// group_t structure.
+/// @param grp the struct where we store the information.
+/// @param buf the buffer from which we extract the information.
+static inline void __parse_line(group_t *grp, char *buf)
+{
+    assert(grp && "Received null grp!");
+    char *token;
+    // Parse the group name.
+    if ((token = strtok(buf, ":")) != NULL)
+        grp->gr_name = token;
+    // Parse the group passwd.
+    if ((token = strtok(NULL, ":")) != NULL)
+        grp->gr_passwd = token;
+    // Parse the group id.
+    if ((token = strtok(NULL, ":")) != NULL)
+        grp->gr_gid = atoi(token);
+
+    size_t found_users = 0;
+    while ((token = strtok(NULL, ",\n\0")) != NULL && found_users < MAX_MEMBERS_PER_GROUP) {
+        grp->gr_mem[found_users] = token;
+        found_users += 1;
+    }
+
+    // Null terminate array
+    grp->gr_mem[found_users] = "\0";
+}
+
+static inline char *__search_entry(int fd, char *buf, int buflen, const char *name, gid_t gid)
+{
+    int ret;
+    char c;
+    int pos = 0;
+    while ((ret = read(fd, &c, 1U))) {
+        // Skip carriage return.
+        if (c == '\r')
+            continue;
+        if (pos >= buflen) {
+            errno = ERANGE;
+            return NULL;
+        }
+        // If we have found a newline or the EOF, parse the entry.
+        if ((c == '\n') || (ret == EOF)) {
+            // Close the buffer.
+            buf[pos] = 0;
+            // Check the entry.
+            if (name) {
+                if (strncmp(buf, name, strlen(name)) == 0)
+                    return buf;
+            } else {
+                int gid_start = -1, col_count = 0;
+                for (int i = 0; i < pos; ++i) {
+                    if (buf[i] == ':') {
+                        if (++col_count == 2) {
+                            gid_start = i + 1;
+                            break;
+                        }
+                    }
+                }
+                if ((gid_start != -1) && (gid_start < pos)) {
+                    // Parse the gid.
+                    int found_gid = atoi(&buf[gid_start]);
+                    // Check the gid.
+                    if (found_gid == gid)
+                        return buf;
+                }
+            }
+            // Reset the index.
+            pos = 0;
+            // If we have reached the EOF stop.
+            if (ret == EOF)
+                break;
+        } else {
+            buf[pos++] = c;
+        }
+    }
+    errno = ENOENT;
+    return NULL;
+}
+
+group_t *getgrgid(gid_t gid)
+{
+    static group_t grp;
+    static char buffer[BUFSIZ];
+
+    group_t *result;
+    if (!getgrgid_r(gid, &grp, buffer, BUFSIZ, &result))
+        return NULL;
+
+    return &grp;
+}
+
+group_t *getgrnam(const char *name)
+{
+    if (name == NULL)
+        return NULL;
+
+    static group_t grp;
+    static char buffer[BUFSIZ];
+
+    group_t *result;
+    if (!getgrnam_r(name, &grp, buffer, BUFSIZ, &result))
+        return NULL;
+
+    return &grp;
+}
+
+int getgrgid_r(gid_t gid, group_t *group, char *buf, size_t buflen, group_t **result)
+{
+    int fd = open("/etc/group", O_RDONLY, 0);
+    if (fd == -1) {
+        errno   = ENOENT;
+        *result = NULL;
+        return 0;
+    }
+
+    char *entry = __search_entry(fd, buf, buflen, NULL, gid);
+    if (entry != NULL) {
+        // Close the file.
+        close(fd);
+        // Parse the line.
+        __parse_line(group, entry);
+        // Return success.
+        return 1;
+    }
+
+    // Close the file.
+    close(fd);
+    // Return fail.
+    return 0;
+}
+
+int getgrnam_r(const char *name, group_t *group, char *buf, size_t buflen, group_t **result)
+{
+    int fd = open("/etc/group", O_RDONLY, 0);
+    if (fd == -1) {
+        errno   = ENOENT;
+        *result = NULL;
+        return 0;
+    }
+
+    char *entry = __search_entry(fd, buf, buflen, name, 0);
+    if (entry != NULL) {
+        // Close the file.
+        close(fd);
+        // Parse the line.
+        __parse_line(group, entry);
+        // Return success.
+        return 1;
+    }
+
+    // Close the file.
+    close(fd);
+    // Return fail.
+    return 0;
+}
+
+group_t *getgrent(void)
+{
+    static group_t result;
+
+    if (__fd == -1) {
+        //pr_debug("Opening group file\n");
+        __fd = open("/etc/group", O_RDONLY, 0);
+        if (__fd == -1) {
+            errno = ENOENT;
+            return 0;
+        }
+    }
+
+    int ret;
+    char c;
+    int pos = 0;
+
+    static char buffer[BUFSIZ];
+    while ((ret = read(__fd, &c, 1U))) {
+        // Skip carriage return.
+        if (c == '\r')
+            continue;
+
+        if (pos >= BUFSIZ) {
+            errno = ERANGE;
+            return NULL;
+        }
+
+        // If we have found a newline or the EOF, parse the entry.
+        if ((c == '\n') || (ret == EOF)) {
+            // Close the buffer.
+            buffer[pos] = 0;
+
+            // Check the entry.
+            if (strlen(buffer) != 0) {
+                //pr_debug("Found entry in group file: %s\n", buffer);
+                __parse_line(&result, buffer);
+                return &result;
+            }
+
+            // If we have reached the EOF stop.
+            if (ret == EOF)
+                break;
+
+        } else {
+            buffer[pos++] = c;
+        }
+    }
+
+    errno = ENOENT;
+    return NULL;
+}
+
+void endgrent(void)
+{
+    //pr_debug("Closing group file\n");
+    close(__fd);
+    __fd = -1;
+}
+
+void setgrent(void)
+{
+    //pr_debug("Resetting pointer to beginning of group file\n");
+    lseek(__fd, 0, SEEK_SET);
+}

libc/src/io/mm_io.c

@@ -0,0 +1,36 @@
+/// @file mm_io.c
+/// @brief Memory Mapped IO functions implementation.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "io/mm_io.h"
+
+uint8_t in_memb(uint32_t addr)
+{
+    return *((uint8_t *) (addr));
+}
+
+uint16_t in_mems(uint32_t addr)
+{
+    return *((uint16_t *) (addr));
+}
+
+uint32_t in_meml(uint32_t addr)
+{
+    return *((uint32_t *) (addr));
+}
+
+void out_memb(uint32_t addr, uint8_t value)
+{
+    (*((uint8_t *) (addr))) = (value);
+}
+
+void out_mems(uint32_t addr, uint16_t value)
+{
+    (*((uint16_t *) (addr))) = (value);
+}
+
+void out_meml(uint32_t addr, uint32_t value)
+{
+    (*((uint32_t *) (addr))) = (value);
+}

libc/src/io/port_io.c

@@ -0,0 +1,57 @@
+/// @file port_io.c
+/// @brief Byte I/O on ports prototypes.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "io/port_io.h"
+
+inline uint8_t inportb(uint16_t port)
+{
+    unsigned char data = 0;
+    __asm__ __volatile__("inb %%dx, %%al" : "=a"(data) : "d"(port));
+
+    return data;
+}
+
+inline uint16_t inports(uint16_t port)
+{
+    uint16_t rv;
+    __asm__ __volatile__("inw %1, %0" : "=a"(rv) : "dN"(port));
+
+    return rv;
+}
+
+void inportsm(uint16_t port, uint8_t *data, unsigned long size)
+{
+    __asm__ __volatile__("rep insw"
+                         : "+D"(data), "+c"(size)
+                         : "d"(port)
+                         : "memory");
+}
+
+inline uint32_t inportl(uint16_t port)
+{
+    uint32_t rv;
+    __asm__ __volatile__("inl %%dx, %%eax" : "=a"(rv) : "dN"(port));
+    return rv;
+}
+
+inline void outportb(uint16_t port, uint8_t data)
+{
+    __asm__ __volatile__("outb %%al, %%dx" ::"a"(data), "d"(port));
+}
+
+inline void outports(uint16_t port, uint16_t data)
+{
+    __asm__ __volatile__("outw %1, %0" : : "dN"(port), "a"(data));
+}
+
+void outportsm(uint16_t port, uint8_t *data, uint16_t size)
+{
+    __asm__ __volatile__("rep outsw" : "+S"(data), "+c"(size) : "d"(port));
+}
+
+inline void outportl(uint16_t port, uint32_t data)
+{
+    __asm__ __volatile__("outl %%eax, %%dx" : : "dN"(port), "a"(data));
+}

libc/src/ipc/ipc.c

@@ -0,0 +1,35 @@
+/// @file ipc.c
+/// @brief Inter-Process Communication (IPC) system call implementation.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "sys/unistd.h"
+#include "system/syscall_types.h"
+#include "sys/errno.h"
+#include "stddef.h"
+#include "ipc/sem.h"
+#include "ipc/shm.h"
+#include "ipc/msg.h"
+
+_syscall3(void *, shmat, int, shmid, const void *, shmaddr, int, shmflg)
+
+_syscall3(long, shmget, key_t, key, size_t, size, int, flag)
+
+_syscall1(long, shmdt, const void *, shmaddr)
+
+_syscall3(long, shmctl, int, shmid, int, cmd, struct shmid_ds *, buf)
+
+_syscall3(long, semget, key_t, key, int, nsems, int, semflg)
+
+_syscall3(long, semop, int, semid, struct sembuf *, sops, unsigned, nsops)
+
+_syscall4(long, semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
+
+_syscall2(long, msgget, key_t, key, int, msgflg)
+
+_syscall4(long, msgsnd, int, msqid, struct msgbuf *, msgp, size_t, msgsz, int, msgflg)
+
+_syscall5(long, msgrcv, int, msqid, struct msgbuf *, msgp, size_t, msgsz, long, msgtyp, int, msgflg)
+
+_syscall3(long, msgctl, int, msqid, int, cmd, struct msqid_ds *, buf)
+

libc/src/libc_start.c

@@ -0,0 +1,37 @@
+/// @file libc_start.c
+/// @brief Contains the programs initialization procedure.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "sys/unistd.h"
+#include "stdlib.h"
+#include "string.h"
+#include "assert.h"
+#include "system/syscall_types.h"
+#include "sys/errno.h"
+
+/// @brief Reference to the `environ` variable in `setenv.c`.
+extern char **environ;
+
+/// @brief The entry point to every program.
+/// @param main Pointer to the main function.
+/// @param argc The number of arguments.
+/// @param argv The pointer to the arguments.
+/// @param envp The pointer to the environmental variables.
+/// @return The return of the `main` function.
+int __libc_start_main(int (*main)(int, char **, char **), int argc, char *argv[], char *envp[])
+{
+    //dbg_print("== START %-30s =======================================\n", argv[0]);
+    //dbg_print("__libc_start_main(%p, %d, %p, %p)\n", main, argc, argv, envp);
+    assert(main && "There is no `main` function.");
+    assert(argv && "There is no `argv` array.");
+    assert(envp && "There is no `envp` array.");
+    //dbg_print("environ  : %p\n", environ);
+    // Copy the environ.
+    environ = envp;
+    // Call the main function.
+    int result = main(argc, argv, envp);
+    // Free the environ.
+    //dbg_print("== END   %-30s =======================================\n", argv[0]);
+    return result;
+}

libc/src/libgen.c

@@ -0,0 +1,140 @@
+/// @file libgen.c
+/// @brief String routines.
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include <assert.h>
+#include <stdlib.h>
+#include <sys/unistd.h>
+#include "libgen.h"
+#include "string.h"
+#include "limits.h"
+
+int parse_path(char *out, char **cur, char sep, size_t max)
+{
+    if (**cur == '\0') {
+        return 0;
+    }
+
+    *out++ = **cur;
+    ++*cur;
+    --max;
+
+    while ((max > 0) && (**cur != '\0') && (**cur != sep)) {
+        *out++ = **cur;
+        ++*cur;
+        --max;
+    }
+
+    *out = '\0';
+
+    return 1;
+}
+
+char *dirname(const char *path)
+{
+    static char s[PATH_MAX];
+
+    static char dot[2] = ".";
+
+    // Check the input path.
+    if (path == NULL) {
+        return dot;
+    }
+
+    // Copy the path to the support string.
+    strcpy(s, path);
+
+    // Get the last occurrence of '/'.
+    char *last_slash = strrchr(s, '/');
+
+    if (last_slash == s) {
+        // If the slash is acutally the first character of the string, move the
+        // pointer to the last slash after it.
+        ++last_slash;
+    } else if ((last_slash != NULL) && (last_slash[1] == '\0')) {
+        // If the slash is the last character, we need to search before it.
+        last_slash = memchr(s, '/', last_slash - s);
+    }
+
+    if (last_slash != NULL) {
+        // If we have found it, close the string.
+        last_slash[0] = '\0';
+    } else {
+        // Otherwise, return '.'.
+        return dot;
+    }
+
+    return s;
+}
+
+char *basename(const char *path)
+{
+    char *p = strrchr(path, '/');
+
+    return p ? p + 1 : (char *)path;
+}
+
+char *realpath(const char *path, char *resolved)
+{
+    assert(path && "Provided null path.");
+    if (resolved == NULL)
+        resolved = malloc(sizeof(char) * PATH_MAX);
+    char abspath[PATH_MAX];
+    // Initialize the absolute path.
+    memset(abspath, '\0', PATH_MAX);
+    int remaining;
+    if (path[0] != '/') {
+        // Get the current task.
+        getcwd(abspath, PATH_MAX);
+        // Check the current task.
+        assert((strlen(abspath) > 0) && "There is no current task.");
+        // Check that the current working directory is an absolute path.
+        assert((abspath[0] == '/') && "Current working directory is not an absolute path.");
+        // Count the remaining space in the absolute path.
+        remaining = PATH_MAX - strlen(abspath) - 1;
+        // Add the separator to the end (se strncat for safety).
+        strncat(abspath, "/", remaining);
+        // Set the number of characters that should be copied,
+        // based on the current absolute path.
+        remaining = PATH_MAX - strlen(abspath) - 1;
+        // Append the path.
+        strncat(abspath, path, remaining);
+    } else {
+        // Copy the path into the absolute path.
+        strncpy(abspath, path, PATH_MAX - 1);
+    }
+    // Count the remaining space in the absolute path.
+    remaining = PATH_MAX - strlen(abspath) - 1;
+    // Add the separator to the end (se strncat for safety).
+    strncat(abspath, "/", remaining);
+
+    int absidx = 0, pathidx = 0;
+
+    while (abspath[absidx]) {
+        // Skip multiple consecutive / characters
+        if (!strncmp("//", abspath + absidx, 2)) {
+            absidx++;
+        }
+        // Go to previous directory if /../ is found
+        else if (!strncmp("/../", abspath + absidx, 4)) {
+            // Go to a valid path character (pathidx points to the next one)
+            if (pathidx)
+                pathidx--;
+            while (pathidx && resolved[pathidx] != '/') {
+                pathidx--;
+            }
+            absidx += 3;
+        } else if (!strncmp("/./", abspath + absidx, 3)) {
+            absidx += 2;
+        } else {
+            resolved[pathidx++] = abspath[absidx++];
+        }
+    }
+    // Remove the last /
+    if (pathidx > 1)
+        resolved[pathidx - 1] = '\0';
+    else
+        resolved[1] = '\0';
+    return resolved;
+}

libc/src/math.c

@@ -0,0 +1,179 @@
+/// @file math.c
+/// @brief
+/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "math.h"
+#include "stdint.h"
+
+double round(double x)
+{
+    double out;
+    __asm__ __volatile__("fldln2; fldl %1; frndint"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+double floor(double x)
+{
+    if (x > -1.0 && x < 1.0) {
+        if (x >= 0)
+            return 0.0;
+        return -1.0;
+    }
+    int i = (int)x;
+    if (x < 0)
+        return (double)(i - 1);
+    return (double)i;
+}
+
+double ceil(double x)
+{
+    if (x > -1.0 && x < 1.0) {
+        if (x <= 0)
+            return 0.0;
+        return 1.0;
+    }
+    int i = (int)x;
+    if (x > 0)
+        return (double)(i + 1);
+    return (double)i;
+}
+
+double pow(double base, double exponent)
+{
+    double out;
+    __asm__ __volatile__("fyl2x;"
+                         "fld %%st;"
+                         "frndint;"
+                         "fsub %%st,%%st(1);"
+                         "fxch;"
+                         "fchs;"
+                         "f2xm1;"
+                         "fld1;"
+                         "faddp;"
+                         "fxch;"
+                         "fld1;"
+                         "fscale;"
+                         "fstp %%st(1);"
+                         "fmulp;"
+                         : "=t"(out)
+                         : "0"(base), "u"(exponent)
+                         : "st(1)");
+    return out;
+}
+
+double exp(double x)
+{
+    return pow(M_E, x);
+}
+
+double fabs(double x)
+{
+    double out;
+    __asm__ __volatile__("fldln2; fldl %1; fabs"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+float fabsf(float x)
+{
+    float out;
+    __asm__ __volatile__("fldln2; fldl %1; fabs"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+double sqrt(double x)
+{
+    double out;
+    __asm__ __volatile__("fldln2; fldl %1; fsqrt"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+float sqrtf(float x)
+{
+    float out;
+    __asm__ __volatile__("fldln2; fldl %1; fsqrt"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+int isinf(double x)
+{
+    union {
+        unsigned long long u;
+        double f;
+    } ieee754;
+    ieee754.f = x;
+    return ((unsigned)(ieee754.u >> 32U) & 0x7fffffffU) == 0x7ff00000U &&
+           ((unsigned)ieee754.u == 0);
+}
+
+int isnan(double x)
+{
+    union {
+        unsigned long long u;
+        double f;
+    } ieee754;
+    ieee754.f = x;
+    return ((unsigned)(ieee754.u >> 32) & 0x7fffffff) +
+               ((unsigned)ieee754.u != 0) >
+           0x7ff00000;
+}
+
+double log10(double x)
+{
+    return ln(x) / ln(10);
+}
+
+double ln(double x)
+{
+    double out;
+    __asm__ __volatile__("fldln2; fldl %1; fyl2x"
+                         : "=t"(out)
+                         : "m"(x));
+    return out;
+}
+
+double logx(double x, double y)
+{
+    // Base may not equal 1 or be negative.
+    if (y == 1.f || y < 0.f || ln(y) == 0.f)
+        return 0.f;
+    return ln(x) / ln(y);
+}
+
+/// Max power for forward and reverse projections.
+#define MAXPOWTWO 4.503599627370496000E+15
+
+double modf(double x, double *intpart)
+{
+    register double absvalue;
+    if ((absvalue = (x >= 0.0) ? x : -x) >= MAXPOWTWO) {
+        // It must be an integer.
+        (*intpart) = x;
+    } else {
+        // Shift fraction off right.
+        (*intpart) = absvalue + MAXPOWTWO;
+        // Shift back without fraction.
+        (*intpart) -= MAXPOWTWO;
+
+        // Above arithmetic might round.
+        while ((*intpart) > absvalue) {
+            // Test again just to be sure.
+            (*intpart) -= 1.0;
+        }
+        if (x < 0.0) {
+            (*intpart) = -(*intpart);
+        }
+    }
+    // Signed fractional part.
+    return (x - (*intpart));
+}