NAME
seteuid, setegid - set effective user or group ID
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
I int seteuid(uid_t euid );
I int setegid(gid_t egid );
DESCRIPTION
R seteuid ()
sets the effective user ID of the current 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
R 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 current process is not privileged (Linux: does not have the
CAP_SETUID
capability in the case of
R seteuid (),
or the
CAP_SETGID
capability in the case of
R setegid ())
and
euid
(resp.
R 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
I seteuid( euid )
is equivalent to
I setreuid(-1, euid )
and hence may change the saved set-user-ID.
Under glibc2.1 it is equivalent to
I setresuid(-1, euid ,-1)
and hence does not change the saved set-user-ID.
Similar remarks hold for
R setegid ().
SEE ALSO
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