[apple/xnu.git] / bsd / man / man2 / setreuid.2

.\" Copyright (c) 1980, 1991, 1993, 1994
.\"	The Regents of the University of California.  All rights reserved.
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.\" modification, are permitted provided that the following conditions
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.\"    notice, this list of conditions and the following disclaimer in the
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.\" 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
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.\"     @(#)setreuid.2	8.2 (Berkeley) 4/16/94
.\" $FreeBSD: src/lib/libc/sys/setreuid.2,v 1.6.2.6 2001/12/14 18:34:01 ru Exp $
.\"
.Dd February 8, 2001
.Dt SETREUID 2
.Os
.Sh NAME
.Nm setreuid
.Nd set real and effective user IDs
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn setreuid "uid_t ruid" "uid_t euid"
.Sh DESCRIPTION
The real and effective user IDs of the
current process are set according to the arguments.
If
.Fa ruid
or
.Fa 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.
.Pp
The
.Fn 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
.Fn seteuid
function (see
.Xr setuid 2 ) .
.Pp
When setting the real and effective user IDs to the same value,
the standard
.Fn setuid
function is preferred.
.Sh RETURN VALUES
.Rv -std setreuid
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er 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.
.El
.Sh SEE ALSO
.Xr getuid 2 ,
.Xr issetugid 2 ,
.Xr seteuid 2 ,
.Xr setuid 2
.Sh HISTORY
The
.Fn setreuid
system call appeared in
.Bx 4.2 .
Commit	Line	Data
6d2010ae A	1	.\" Copyright (c) 1980, 1991, 1993, 1994
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)setreuid.2 8.2 (Berkeley) 4/16/94
	33	.\" $FreeBSD: src/lib/libc/sys/setreuid.2,v 1.6.2.6 2001/12/14 18:34:01 ru Exp $
	34	.\"
	35	.Dd February 8, 2001
	36	.Dt SETREUID 2
	37	.Os
	38	.Sh NAME
	39	.Nm setreuid
	40	.Nd set real and effective user IDs
	41	.Sh LIBRARY
	42	.Lb libc
	43	.Sh SYNOPSIS
	44	.In unistd.h
	45	.Ft int
	46	.Fn setreuid "uid_t ruid" "uid_t euid"
	47	.Sh DESCRIPTION
	48	The real and effective user IDs of the
	49	current process are set according to the arguments.
	50	If
	51	.Fa ruid
	52	or
	53	.Fa euid
	54	is -1, the current uid is filled in by the system.
	55	Unprivileged users may change the real user
	56	ID to the effective user ID and vice-versa; only the super-user may
	57	make other changes.
	58	.Pp
	59	The
	60	.Fn setreuid
	61	function has been used to swap the real and effective user IDs
	62	in set-user-ID programs to temporarily relinquish the set-user-ID value.
	63	This purpose is now better served by the use of the
	64	.Fn seteuid
65	function (see
66	.Xr setuid 2 ) .
67	.Pp
68	When setting the real and effective user IDs to the same value,
69	the standard
70	.Fn setuid
71	function is preferred.
72	.Sh RETURN VALUES
73	.Rv -std setreuid
74	.Sh ERRORS
75	.Bl -tag -width Er
76	.It Bq Er EPERM
77	The current process is not the super-user and a change
78	other than changing the effective user-id to the real user-id
79	was specified.
80	.El
81	.Sh SEE ALSO
82	.Xr getuid 2 ,
83	.Xr issetugid 2 ,
84	.Xr seteuid 2 ,
85	.Xr setuid 2
86	.Sh HISTORY
87	The
88	.Fn setreuid
89	system call appeared in
90	.Bx 4.2 .