getresgid(2) [debian man page]

SETRESUID(2)						      BSD System Calls Manual						      SETRESUID(2)

NAME

     getresgid, getresuid, setresgid, setresuid -- get or set real, effective and saved user or group ID

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/types.h>
     #include <unistd.h>

     int
     getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);

     int
     getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);

     int
     setresgid(gid_t rgid, gid_t egid, gid_t sgid);

     int
     setresuid(uid_t ruid, uid_t euid, uid_t suid);

DESCRIPTION

     The setresuid() system call sets the real, effective and saved user IDs of the current process.  The analogous setresgid() sets the real,
     effective and saved group IDs.

     Privileged processes may set these IDs to arbitrary values.  Unprivileged processes are restricted in that each of the new IDs must match one
     of the current IDs.

     Passing -1 as an argument causes the corresponding value to remain unchanged.

     The getresgid() and getresuid() calls retrieve the real, effective, and saved group and user IDs of the current process, respectively.

RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS

     [EPERM]		The calling process was not privileged and tried to change one or more IDs to a value which was not the current real ID,
			the current effective ID nor the current saved ID.

     [EFAULT]		An address passed to getresgid() or getresuid() was invalid.

SEE ALSO

     getegid(2), geteuid(2), getgid(2), getuid(2), issetugid(2), setgid(2), setregid(2), setreuid(2), setuid(2)

STANDARDS

     These system calls are not available on many platforms.  They exist in FreeBSD to support Linux binaries linked against GNU libc2.

HISTORY

     These functions first appeared in HP-UX.

BSD
								  April 13, 2001							       BSD

GETRESUID(2)                                                 Linux Programmer's Manual                                                GETRESUID(2)

NAME

       getresuid, getresgid - get real, effective and saved user/group IDs

SYNOPSIS

       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <unistd.h>

       int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
       int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);

DESCRIPTION

       getresuid()  returns  the  real  UID, the effective UID, and the saved set-user-ID of the calling process, in the arguments ruid, euid, and
       suid, respectively.  getresgid() performs the analogous task for the process's group IDs.

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EFAULT One of the arguments specified an address outside the calling program's address space.

VERSIONS

       These system calls appeared on Linux starting with kernel 2.1.44.

       The prototypes are given by glibc since version 2.3.2, provided _GNU_SOURCE is defined.

CONFORMING TO

       These calls are nonstandard; they also appear on HP-UX and some of the BSDs.

NOTES

       The original Linux getresuid() and getresgid() system calls supported only 16-bit user and group IDs.  Subsequently, Linux 2.4 added getre-
       suid32()  and  getresgid32(),  supporting  32-bit IDs.  The glibc getresuid() and getresgid() wrapper functions transparently deal with the
       variations across kernel versions.

SEE ALSO

       getuid(2), setresuid(2), setreuid(2), setuid(2), credentials(7)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux                                                               2017-09-15                                                        GETRESUID(2)