SETEUID
Section: Linux Programmer's Manual (2)
Updated: 2009-10-17
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NAME
seteuid, setegid - set effective user or group ID
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int seteuid(uid_t euid);
int setegid(gid_t egid);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
seteuid(),
setegid():
-
_BSD_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
DESCRIPTION
seteuid()
sets the effective user ID of the calling process.
Unprivileged user processes may only set the effective user ID to the
real user ID, the effective user ID or the saved set-user-ID.
Precisely the same holds for
setegid()
with "group" instead of "user".
RETURN VALUE
On success, zero is returned.
On error, -1 is returned, and
errno
is set appropriately.
ERRORS
- EPERM
-
The calling process is not privileged (Linux: does not have the
CAP_SETUID
capability in the case of
seteuid(),
or the
CAP_SETGID
capability in the case of
setegid())
and
euid
(respectively,
egid)
is not the real user (group) ID, the effective user (group) ID,
or the saved set-user-ID (saved set-group-ID).
CONFORMING TO
4.3BSD, POSIX.1-2001.
NOTES
Setting the effective user (group) ID to the
saved set-user-ID (saved set-group-ID) is
possible since Linux 1.1.37 (1.1.38).
On an arbitrary system one should check
_POSIX_SAVED_IDS.
Under libc4, libc5 and glibc 2.0
seteuid(euid)
is equivalent to
setreuid(-1, euid)
and hence may change the saved set-user-ID.
Under glibc 2.1 and later it is equivalent to
setresuid(-1, euid, -1)
and hence does not change the saved set-user-ID.
Similar remarks hold for
setegid().
According to POSIX.1,
seteuid()
(setegid())
need not permit
euid
(egid)
to be the same value as the current effective user (group) ID,
and some implementations do not permit this.
SEE ALSO
geteuid(2),
setresuid(2),
setreuid(2),
setuid(2),
capabilities(7),
credentials(7)
COLOPHON
This page is part of release 3.27 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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Time: 19:49:19 GMT, April 27, 2011