.\" Copyright (c) 1983, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     From: @(#)setuid.3	6.4 (Berkeley) 4/19/91
.\"	$Id: setuid.2,v 1.2 1994/04/21 21:30:20 wollman Exp $
.\"
.Dd March 16, 1994
.Dt SETUID 2
.Os
.Sh NAME
.Nm setuid ,
.Nm seteuid ,
.\" .Nm setruid ,
.Nm setgid ,
.Nm setegid ,
.\" .Nm setrgid
.Nd set user and group ID
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Ft int
.Fn setuid "uid_t uid"
.Ft int
.Fn seteuid "uid_t euid"
.\" .Ft int
.\" .Fn setruid "uid_t ruid"
.Ft int
.Fn setgid "gid_t gid"
.Ft int
.Fn setegid "gid_t egid"
.\" .Ft int
.\" .Fn setrgid "gid_t rgid"
.Sh DESCRIPTION
The
.Fn setuid
function
.Pq Fn setgid
sets the real, effective, and saved
user IDs (group IDs) of the current process
as specified.
.Pp
The
.Fn seteuid
function
.Pq Fn setegid
sets the effective user ID (group ID) of the
current process.
.\".Pp
.\" The
.\" .Fn setruid
.\" function
.\" .Pq Fn setrgid
.\" sets the real user ID (group ID) of the
.\" current process.
.Pp
When any of these calls succeed, the
.Dv SUGID
process flag is turned on, and remains on until the process calls
.Xr execve 2 ;
this flag can be inspected with
.Xr ps 1 .
.Sh RETURN VALUES
Upon success, these functions return 0;
otherwise \-1 is returned.
.Pp
If the user is not the super user, and the ID specified is not the
current real ID, the
.Nm setuid
and
.Nm setgid
functions return \-1.
.Pp
If the user is not the super user, and the ID specfied is not the
current real ID, the
.\" nor the saved ID, the
.\" should this really be true that setuid(geteuid()) is not allowed?
.Nm seteuid
and
.Nm setegid
functions return \-1.
.Sh SEE ALSO
.Xr setreuid 2 ,
.Xr setregid 2 ,
.Xr getuid 2 ,
.Xr getgid 2 ,
.Xr execve 2 ,
.Xr ps 1
.Sh HISTORY
A
.Fn setuid
and
.Fn setgid
syscall appeared in 
.At v6 .