Fix difference between PGID and GID. Correctly set UID and GID of new processes. Implement set/get PGID and GID.

libc/CMakeLists.txt

@@ -89,8 +89,12 @@ add_library(
     ${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

libc/inc/fcntl.h

@@ -20,20 +20,21 @@
 /// @brief The file modes.
 /// @{
 
-#define S_IRWXU 0000700U ///< RWX mask for user.
-#define S_IRUSR 0000400U ///< R for user.
-#define S_IWUSR 0000200U ///< W for user.
-#define S_IXUSR 0000100U ///< X for user.
-
-#define S_IRWXG 0000070U ///< RWX mask for group.
-#define S_IRGRP 0000040U ///< R for group.
-#define S_IWGRP 0000020U ///< W for group.
-#define S_IXGRP 0000010U ///< X for group.
-
-#define S_IRWXO 0000007U ///< RWX mask for group.
-#define S_IROTH 0000004U ///< R for group.
-#define S_IWOTH 0000002U ///< W for group.
-#define S_IXOTH 0000001U ///< X for group.
+#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

libc/inc/sys/unistd.h

@@ -84,6 +84,19 @@ extern pid_t getsid(pid_t pid);
 ///        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();
@@ -94,6 +107,16 @@ extern pid_t getgid();
 ///        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();

libc/src/unistd/getpgid.c

@@ -0,0 +1,11 @@
+///                MentOS, The Mentoring Operating system project
+/// @file getpgid.c
+/// @brief
+/// @copyright (c) 2014-2021 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"
+
+_syscall1(pid_t, getpgid, pid_t, pid)

libc/src/unistd/getuid.c

@@ -0,0 +1,11 @@
+///                MentOS, The Mentoring Operating system project
+/// @file getuid.c
+/// @brief
+/// @copyright (c) 2014-2021 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"
+
+_syscall0(uid_t, getuid)

libc/src/unistd/setpgid.c

@@ -0,0 +1,11 @@
+///                MentOS, The Mentoring Operating system project
+/// @file setpgid.c
+/// @brief
+/// @copyright (c) 2014-2021 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"
+
+_syscall2(int, setpgid, pid_t, pid, pid_t, pgid)

libc/src/unistd/setuid.c

@@ -0,0 +1,11 @@
+///                MentOS, The Mentoring Operating system project
+/// @file setuid.c
+/// @brief
+/// @copyright (c) 2014-2021 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"
+
+_syscall1(int, setuid, uid_t, pid)