NAME
setreuid —
set real and effective user
ID's
LIBRARY
library “libc”
SYNOPSIS
#include
<unistd.h>
int
setreuid(uid_t
ruid, uid_t
euid);
DESCRIPTION
The real and effective user IDs of the current process are set according to the arguments. 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 vice-versa; only the super-user may make other changes.If the real user ID is changed (i.e. ruid is not -1) or the effective user ID is changed to something other than the real user ID, then the saved user ID will be set to the effective user ID.
The
setreuid()
system call 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(2) system call.
When setting the real and effective user IDs to the
same value, the standard
setuid()
system call is preferred.
RETURN VALUES
The setreuid() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable 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
HISTORY
The setreuid() system call appeared in
4.2BSD.