setreuid, setregid - set real and/or effective user or
group ID
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int setreuid(uid_t ruid, uid_t euid);
int setregid(gid_t rgid, gid_t egid);
DESCRIPTION
setreuid sets real and effective user IDs of the current
process. Unprivileged users may only set the real user ID
to the real user ID or the effective user ID, and may only
set the effective user ID to the real user ID, the effec
tive user ID or the saved user ID.
Supplying a value of -1 for either the real or effective
user ID forces the system to leave that ID unchanged.
If the real user ID is set or the effective user ID is set
to a value not equal to the previous real user ID, the
saved user ID will be set to the new effective user ID.
Completely analogously, setregid sets real and effective
group ID's of the current process, and all of the above
holds 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 the super-user and
changes other than (i) swapping the effective user
(group) ID with the real user (group) ID, or (ii)
setting one to the value of the other or (iii) set
ting the effective user (group) ID to the value of
the saved user (group) ID was specified.
NOTES
Setting the effective user (group) ID to the saved user ID
is possible since Linux 1.1.37 (1.1.38).
CONFORMING TO
BSD 4.3 (the setreuid and setregid function calls first
appeared in 4.2BSD).
SEE ALSO
getuid(2), getgid(2), setuid(2), setgid(2), seteuid(2),
setresuid(2)
Man(1) output converted with
man2html