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

NAME

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

SYNOPSIS

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

       int setresuid(uid_t ruid, uid_t euid, uid_t suid);
       int setresgid(gid_t rgid, gid_t egid, gid_t sgid);

DESCRIPTION

       setresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process.

       Unprivileged  user  processes may change the real UID, effective UID, and saved set-user-ID, each to one of: the current real UID, the cur-
       rent effective UID or the current saved set-user-ID.

       Privileged processes (on Linux, those having the CAP_SETUID capability) may set the real UID, effective UID, and saved set-user-ID to arbi-
       trary values.

       If one of the arguments equals -1, the corresponding value is not changed.

       Regardless  of  what  changes are made to the real UID, effective UID, and saved set-user-ID, the file system UID is always set to the same
       value as the (possibly new) effective UID.

       Completely analogously, setresgid() sets the real GID, effective GID, and saved set-group-ID of the calling process  (and  always  modifies
       the file system GID to be the same as the effective GID), with the same restrictions for unprivileged processes.

RETURN VALUE

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

ERRORS

       EAGAIN uid does not match the current UID and this call would bring that user ID over its RLIMIT_NPROC resource limit.

       EPERM  The  calling  process  is not privileged (did not have the CAP_SETUID capability) and tried to change the IDs to values that are not
	      permitted.

VERSIONS

       These calls are available under Linux since Linux 2.1.44.

CONFORMING TO

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

NOTES

       Under HP-UX and FreeBSD, the prototype is found in <unistd.h>.  Under Linux the prototype is provided by glibc since version 2.3.2.

       The original Linux setresuid() and setresgid() system calls supported only 16-bit user and group IDs.  Subsequently, Linux 2.4 added setre-
       suid32()  and  setresgid32(),  supporting  32-bit IDs.  The glibc setresuid() and setresgid() wrapper functions transparently deal with the
       variations across kernel versions.

SEE ALSO

       getresuid(2), getuid(2), setfsgid(2), setfsuid(2), setreuid(2), setuid(2), capabilities(7), credentials(7)

COLOPHON

       This page is part of release 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2010-11-22							      SETRESUID(2)