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 current 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 arbitrary 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 filesystem 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 filesystem 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 setresuid32() 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 3.54 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/.


  Copyright (C) 1997 Andries Brouwer (aebcwi.nl)

%%%LICENSE_START(VERBATIM)
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
%%%LICENSE_END

Modified, 2003-05-26, Michael Kerrisk, <mtk.manpagesgmail.com>