Finish v0.3.0

2019-05-08 17:07:11 +02:00
parent 3d9beb5ee0
commit 7d9085fecf
330 changed files with 45755 additions and 0 deletions
@@ -0,0 +1,55 @@
+///                MentOS, The Mentoring Operating system project
+/// @file dirent.h
+/// @brief Functions used to manage directories.
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// The maximum length for a name.
+#define NAME_MAX 30
+
+/// @brief Contains the entries of a directory.
+typedef struct dirent_t
+{
+    /// The inode of the entry.
+    ino_t d_ino;
+
+    /// The type of the entry.
+    int d_type;
+
+    /// The nam of the entry.
+    char d_name[NAME_MAX + 1];
+} dirent_t;
+
+/// @brief Contains information concerning a directory.
+typedef struct DIR
+{
+    /// Filesystem directory handle.
+    int handle;
+
+    /// The currently opened entry.
+    ino_t cur_entry;
+
+    /// Path to the directory.
+    char path[NAME_MAX + 1];
+
+    /// Next directory item.
+    dirent_t entry;
+} DIR;
+
+/// @brief      Opens a directory and returns a handler to it.
+/// @param path The path of the directory.
+/// @return     Pointer to the directory. Otherwise, NULL.
+DIR *opendir(const char *path);
+
+/// @brief Given a pointer to a directory, it closes it.
+int closedir(DIR *dirp);
+
+/// @brief At each call of this function, it returns a pointer to the next
+/// element inside the directory.
+/// @return A pointer to the next element. If there are no more elments, it
+/// returns NULL.
+dirent_t *readdir(DIR *dirp);
@@ -0,0 +1,383 @@
+///                MentOS, The Mentoring Operating system project
+/// @file process.c
+/// @brief System call errors definition.
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+extern int *__geterrno();
+
+#define errno (*__geterrno())
+
+/// Operation not permitted.
+#define EPERM 1
+
+/// No such file or directory.
+#define ENOENT 2
+
+/// No such process.
+#define ESRCH 3
+
+/// Interrupted system call.
+#define EINTR 4
+
+///I/O error.
+#define EIO 5
+
+/// No such device or address.
+#define ENXIO 6
+
+/// Arg list too long.
+#define E2BIG 7
+
+/// Exec format error.
+#define ENOEXEC 8
+
+/// Bad file number.
+#define EBADF 9
+
+/// No child processes.
+#define ECHILD 10
+
+/// Try again.
+#define EAGAIN 11
+
+/// Out of memory.
+#define ENOMEM 12
+
+/// Permission denied.
+#define EACCES 13
+
+/// Bad address.
+#define EFAULT 14
+
+/// Block device required.
+#define ENOTBLK 15
+
+/// Device or resource busy.
+#define EBUSY 16
+
+/// File exists.
+#define EEXIST 17
+
+/// Cross-device link.
+#define EXDEV 18
+
+/// No such device.
+#define ENODEV 19
+
+/// Not a directory.
+#define ENOTDIR 20
+
+/// Is a directory.
+#define EISDIR 21
+
+/// Invalid argument.
+#define EINVAL 22
+
+/// File table overflow.
+#define ENFILE 23
+
+/// Too many open files.
+#define EMFILE 24
+
+/// Not a typewriter.
+#define ENOTTY 25
+
+/// Text file busy.
+#define ETXTBSY 26
+
+/// File too large.
+#define EFBIG 27
+
+/// No space left on device.
+#define ENOSPC 28
+
+/// Illegal seek.
+#define ESPIPE 29
+
+/// Read-only file system.
+#define EROFS 30
+
+/// Too many links.
+#define EMLINK 31
+
+/// Broken pipe.
+#define EPIPE 32
+
+/// Math argument out of domain of func.
+#define EDOM 33
+
+/// Math result not representable.
+#define ERANGE 34
+
+/// Resource deadlock would occur.
+#define EDEADLK 35
+
+/// File name too long.
+#define ENAMETOOLONG 36
+
+/// No record locks available.
+#define ENOLCK 37
+
+/// Function not implemented.
+#define ENOSYS 38
+
+/// Directory not empty.
+#define ENOTEMPTY 39
+
+/// Too many symbolic links encountered.
+#define ELOOP 40
+
+/// Operation would block.
+#define EWOULDBLOCK EAGAIN
+
+/// No message of desired type.
+#define ENOMSG 42
+
+/// Identifier removed.
+#define EIDRM 43
+
+/// Channel number out of range.
+#define ECHRNG 44
+
+/// Level 2 not synchronized.
+#define EL2NSYNC 45
+
+/// Level 3 halted.
+#define EL3HLT 46
+
+/// Level 3 reset.
+#define EL3RST 47
+
+/// Link number out of range.
+#define ELNRNG 48
+
+/// Protocol driver not attached.
+#define EUNATCH 49
+
+/// No CSI structure available.
+#define ENOCSI 50
+
+/// Level 2 halted.
+#define EL2HLT 51
+
+/// Invalid exchange.
+#define EBADE 52
+
+/// Invalid request descriptor.
+#define EBADR 53
+
+/// Exchange full.
+#define EXFULL 54
+
+/// No anode.
+#define ENOANO 55
+
+/// Invalid request code.
+#define EBADRQC 56
+
+/// Invalid slot.
+#define EBADSLT 57
+
+// TODO: doxygen comment.
+#define EDEADLOCK EDEADLK
+
+/// Bad font file format.
+#define EBFONT 59
+
+/// Device not a stream.
+#define ENOSTR 60
+
+/// No data available.
+#define ENODATA 61
+
+/// Timer expired.
+#define ETIME 62
+
+/// Out of streams resources.
+#define ENOSR 63
+
+/// Machine is not on the network.
+#define ENONET 64
+
+/// Package not installed.
+#define ENOPKG 65
+
+/// Object is remote.
+#define EREMOTE 66
+
+/// Link has been severed.
+#define ENOLINK 67
+
+/// Advertise error.
+#define EADV 68
+
+/// Srmount error.
+#define ESRMNT 69
+
+/// Communication error on send.
+#define ECOMM 70
+
+/// Protocol error.
+#define EPROTO 71
+
+/// Multihop attempted.
+#define EMULTIHOP 72
+
+/// RFS specific error.
+#define EDOTDOT 73
+
+/// Not a data message.
+#define EBADMSG 74
+
+/// Value too large for defined data type.
+#define EOVERFLOW 75
+
+/// Name not unique on network.
+#define ENOTUNIQ 76
+
+/// File descriptor in bad state.
+#define EBADFD 77
+
+/// Remote address changed.
+#define EREMCHG 78
+
+/// Can not access a needed shared library.
+#define ELIBACC 79
+
+/// Accessing a corrupted shared library.
+#define ELIBBAD 80
+
+/// .lib section in a.out corrupted.
+#define ELIBSCN 81
+
+/// Attempting to link in too many shared libraries.
+#define ELIBMAX 82
+
+/// Cannot exec a shared library directly.
+#define ELIBEXEC 83
+
+/// Illegal byte sequence.
+#define EILSEQ 84
+
+/// Interrupted system call should be restarted.
+#define ERESTART 85
+
+/// Streams pipe error.
+#define ESTRPIPE 86
+
+/// Too many users.
+#define EUSERS 87
+
+///Socket operation on non-socket.
+#define ENOTSOCK 88
+
+/// Destination address required.
+#define EDESTADDRREQ 89
+
+/// Message too long.
+#define EMSGSIZE 90
+
+/// Protocol wrong type for socket.
+#define EPROTOTYPE 91
+
+/// Protocol not available.
+#define ENOPROTOOPT 92
+
+/// Protocol not supported.
+#define EPROTONOSUPPORT 93
+
+/// Socket type not supported.
+#define ESOCKTNOSUPPORT 94
+
+/// Operation not supported on transport endpoint.
+#define EOPNOTSUPP 95
+
+/// Protocol family not supported.
+#define EPFNOSUPPORT 96
+
+/// Address family not supported by protocol.
+#define EAFNOSUPPORT 97
+
+/// Address already in use.
+#define EADDRINUSE 98
+
+/// Cannot assign requested address.
+#define EADDRNOTAVAIL 99
+
+/// Network is down.
+#define ENETDOWN 100
+
+/// Network is unreachable.
+#define ENETUNREACH 101
+
+/// Network dropped connection because of reset.
+#define ENETRESET 102
+
+/// Software caused connection abort.
+#define ECONNABORTED 103
+
+/// Connection reset by peer.
+#define ECONNRESET 104
+
+/// No buffer space available.
+#define ENOBUFS 105
+
+/// Transport endpoint is already connected.
+#define EISCONN 106
+
+/// Transport endpoint is not connected.
+#define ENOTCONN 107
+
+/// Cannot send after transport endpoint shutdown.
+#define ESHUTDOWN 108
+
+/// Too many references: cannot splice.
+#define ETOOMANYREFS 109
+
+/// Connection timed out.
+#define ETIMEDOUT 110
+
+/// Connection refused.
+#define ECONNREFUSED 111
+
+/// Host is down.
+#define EHOSTDOWN 112
+
+/// No route to host.
+#define EHOSTUNREACH 113
+
+///Operation already in progress.
+#define EALREADY 114
+
+/// Operation now in progress.
+#define EINPROGRESS 115
+
+/// Stale NFS file handle.
+#define ESTALE 116
+
+/// Structure needs cleaning.
+#define EUCLEAN 117
+
+/// Not a XENIX named type file.
+#define ENOTNAM 118
+
+/// No XENIX semaphores available.
+#define ENAVAIL 119
+
+/// Is a named type file.
+#define EISNAM 120
+
+/// Remote I/O error.
+#define EREMOTEIO 121
+
+/// Quota exceeded.
+#define EDQUOT 122
+
+/// No medium found.
+#define ENOMEDIUM 123
+
+/// Wrong medium type.
+#define EMEDIUMTYPE 124
@@ -0,0 +1,53 @@
+///                MentOS, The Mentoring Operating system project
+/// @file ipc.h
+/// @brief
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "stddef.h"
+
+/// Create key if key does not exist.
+#define IPC_CREAT	01000
+
+/// Fail if key exists.
+#define IPC_EXCL	02000
+
+/// Return error on wait.
+#define IPC_NOWAIT	04000
+
+/// Remove identifier.
+#define IPC_RMID	0
+
+/// Set `ipc_perm' options.
+#define IPC_SET		1
+
+/// Get `ipc_perm' options.
+#define IPC_STAT	2
+
+/// See ipcs.
+#define IPC_INFO	3
+
+struct ipc_perm {
+    /// Creator user id.
+    uid_t	cuid;
+
+    /// Creator group id.
+    gid_t	cgid;
+
+    /// User id.
+    uid_t	uid;
+
+    /// Group id.
+    gid_t	gid;
+
+    /// r/w permission.
+    ushort	mode;
+
+    /// Sequence # (to generate unique msg/sem/shm id).
+    ushort	seq;
+
+    /// User specified msg/sem/shm key.
+    key_t	key;
+};
@@ -0,0 +1,7 @@
+///                MentOS, The Mentoring Operating system project
+/// @file module.h
+/// @brief
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
@@ -0,0 +1,43 @@
+///                MentOS, The Mentoring Operating system project
+/// @file reboot.h
+/// @brief
+/// @copyright (c) 2019 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
+
+#define LINUX_REBOOT_MAGIC2 672274793
+
+#define LINUX_REBOOT_MAGIC2A 85072278
+
+#define LINUX_REBOOT_MAGIC2B 369367448
+
+#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
@@ -0,0 +1,132 @@
+///                MentOS, The Mentoring Operating system project
+/// @file shm.h
+/// @brief
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "ipc.h"
+#include "debug.h"
+#include "clock.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
+
+typedef unsigned long shmatt_t;
+
+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;
+
+	struct shmid_ds *next;
+
+	// Where shm created is memorized, should be a file.
+	void *shm_location;
+};
+
+/// @@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);
@@ -0,0 +1,42 @@
+///                MentOS, The Mentoring Operating system project
+/// @file stat.h
+/// @brief Stat functions.
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "clock.h"
+#include "stddef.h"
+
+/// @brief Data structure which contains information about a file.
+typedef struct stat_t
+{
+    /// ID of device containing file.
+    dev_t st_dev;
+    /// Fle serial number.
+    ino_t st_ino;
+    /// Mode of file.
+    mode_t st_mode;
+    /// User id del file.
+    uid_t st_uid;
+    /// Group id del file.
+    gid_t st_gid;
+    /// Dimensione del file.
+    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;
+
+/// @brief      Retrieves information about the file at the given location.
+/// @param path 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 stat(const char *path, stat_t *buf);
+
+// TODO: doxygen comment.
+int mkdir(const char *path, mode_t mode);
@@ -0,0 +1,67 @@
+///                MentOS, The Mentoring Operating system project
+/// @file types.h
+/// @brief Collection of Kernel datatype
+/// @copyright (c) 2019 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;
+
+/// 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;
@@ -0,0 +1,95 @@
+///                MentOS, The Mentoring Operating system project
+/// @file unistd.h
+/// @brief Functions used to manage files.
+/// @copyright (c) 2019 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+#include "types.h"
+#include "stddef.h"
+
+//======== Standard file descriptors ===========================================
+/// Standard input.
+#define STDIN_FILENO -3
+
+/// Standard output.
+#define STDOUT_FILENO -2
+
+/// Standard error output.
+#define STDERR_FILENO -1
+//==============================================================================
+
+/// Maximum number of opened file.
+#define MAX_OPEN_FD 4
+
+/// @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    Used to set the file status flags and file access modes
+///                 of the open file description.
+/// @param mode     Specifies the file mode bits be applied when a new file
+///                 is created.
+/// @return         Returns a file descriptor, a small, nonnegative integer for
+///                 use in subsequent system calls.
+int open(const char *pathname, int flags, mode_t mode);
+
+/// @brief        Close a file descriptor.
+/// @param fildes The file descriptor.
+/// @return       The result of the operation.
+int close(int fildes);
+
+/// @brief      Removes the given directory.
+/// @param path The path to the directory to remove.
+/// @return
+int rmdir(const char *path);
+
+/// @brief Wrapper for exit system call.
+extern void exit(int status);
+
+/// @brief        Return the process identifier of the calling process.
+/// @return pid_t process identifier.
+extern pid_t getpid();
+
+/// @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 -1 for errors, 0 to the new
+///        process, and the process ID of the new process to the old process.
+/// @return
+extern pid_t vfork();
+
+/// @brief      Replaces the current process image with a new process image.
+/// @param path The path to the binary file to execute.
+/// @param argv The list of arguments.
+/// @param envp
+/// @return
+extern int execve(const char *path, 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      Reboot system call.
+/// @param cmd
+/// @param arg
+/// @return
+int reboot(int magic1, int magic2, unsigned int cmd, void *arg);
+
+void getcwd(char *path, size_t size);
+
+void chdir(char const *path);
@@ -0,0 +1,29 @@
+///                MentOS, The Mentoring Operating system project
+/// @file utsname.h
+/// @brief Functions used to provide information about the machine & OS.
+/// @copyright (c) 2019 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];
+
+    /// The version of the OS.
+    char version[SYS_LEN];
+
+    /// The name of the machine.
+    char machine[SYS_LEN];
+} utsname_t;
+
+/// @brief Sets the values of os_infos.
+int uname(utsname_t *os_infos);
@@ -0,0 +1,60 @@
+///                MentOS, The Mentoring Operating system project
+/// @file wait.h
+/// @brief
+/// @copyright (c) 2019 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
+
+/// @brief Return for children that are stopped, and whose status has not
+///        been reported.
+#define WUNTRACED 0x00000002
+
+/// @brief returns true if the child process exited because of a signal that
+///        was not caught.
+#define WIFSIGNALED(status) (!WIFSTOPPED(status) && !WIFEXITED(status))
+
+/// @brief returns true if the child process that caused the return is
+///        currently stopped; this is only possible if the call was done using
+///        WUNTRACED().
+#define WIFSTOPPED(status) (((status)&0xff) == 0x7f)
+
+/// @brief evaluates to the least significant eight bits of the return code
+///        of the child that terminated, which may have been set as the argument
+///        to a call to exit() or as the argument for a return statement in the
+///        main  program. This macro can only be evaluated if WIFEXITED()
+///        returned nonzero.
+#define WEXITSTATUS(status) (((status)&0xff00) >> 8)
+
+/// @brief returns the number of the signal that caused the child process to
+///        terminate. This macro can only be evaluated if WIFSIGNALED() returned
+///        nonzero.
+#define WTERMSIG(status) ((status)&0x7f)
+
+/// @brief Is nonzero if the child exited normally.
+#define WIFEXITED(status) (WTERMSIG(status) == 0)
+
+/// @brief returns the number of the signal that caused the child to stop.
+///        This macro can only be evaluated if WIFSTOPPED() returned nonzero.
+#define WSTOPSIG(status) (WEXITSTATUS(status))
+
+extern pid_t wait(int *status);
+
+/// @brief   Suspends the execution of the calling thread until a child
+///          specified by pid argument has changed state.
+/// @details
+///          By default, waitpid() waits only for terminated children, but this
+///          behavior is modifiable via the options argument, as described below.
+///          The value of pid can be:
+///        - 1    meaning wait for any child process.
+///          0    meaning wait for any child process whose process group ID is
+///               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);