NAME
setreuid —
set real and effective user
ID's
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
setreuid(
uid_t
ruid,
uid_t euid);
DESCRIPTION
The real and effective user ID's of the current process are set according to the
arguments. If the real user ID is changed, the saved user ID is changed to the
new value of the effective user ID.
If
ruid or
euid is -1, the current
uid is filled in by the system. Unprivileged users may change the real user ID
to the effective user ID, and may change the effective user ID to the real
user ID or the saved user ID; only the super-user may make other changes.
The
setreuid() function has been used to swap the real and
effective user IDs in set-user-ID programs to temporarily relinquish the
set-user-ID value. This purpose is now better served by the use of the
seteuid() function (see
setuid(2)).
When setting the real and effective user IDs to the same value, this function is
equivalent to the
setuid() function. When setting only the
effective user ID, this function is equivalent to the
seteuid() function.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1
is returned and
errno is set to indicate the error.
ERRORS
-
-
- [
EPERM
]
- The current process is not the super-user and a change
other than changing the effective user-id to the real user-id was
specified.
SEE ALSO
getuid(2),
seteuid(2),
setgid(2),
setuid(2)
HISTORY
The
setreuid() function call appeared in
4.2BSD. An incompatible version was implemented in
4.4BSD. It was reimplemented in
NetBSD 1.2 in a way compatible with
4.3BSD, SunOS and Linux, but should not be used in new
code.