SETEGID(2) Linux Programmer's Manual SETEGID(2)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);
DESCRIPTIONseteuid() sets the effective user ID of the current process. Unprivi‐
leged 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 current process is not privileged (Linux: does not have the
CAP_SETUID capability in the case of seteuid(), or the CAP_SET‐
GID capability in the case of setegid()) and euid (resp. egid)
is not the real user (group) ID, the effective user (group) ID,
or the saved set-user-ID (saved set-group-ID).
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 glibc2.0 seteuid(euid) is equivalent to
setreuid(-1, euid) and hence may change the saved set-user-ID. Under
glibc2.1 it is equivalent to setresuid(-1, euid,-1) and hence does not
change the saved set-user-ID. Similar remarks hold for setegid().
CONFORMING TO
4.3BSD, POSIX.1-2001.
SEE ALSOgeteuid(2), setresuid(2), setreuid(2), setuid(2), capabilities(7)Linux 2.6.6 2004-05-27 SETEGID(2)