.\" Copyright (C), 1994, Graeme W. Wilford (Wilf).
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Fri Jul 29th 12:56:44 BST 1994  Wilf. <G.Wilford@ee.surrey.ac.uk>
.\" Changes inspired by patch from Richard Kettlewell
.\"   <richard@greenend.org.uk>, aeb 970616.
.\" Modified, 27 May 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"     Added notes on capability requirements
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated Sat Mar  1 16:32:11 JST 1997
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified Sun Sep 28 20:26:49 JST 1997
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated & Modified Sat May 22 18:21:45 JST 2004
.\"         by Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified Wed Jan  5 00:51:28 JST 2005 by Yuichi SATO
.\"
.\"WORD:	identity		
.\"WORD:	effective user ID	¸桼ID
.\"WORD:	real user ID		¥桼ID
.\"WORD:	saved user ID		¸桼ID
.\"WORD:	implement		
.\"WORD:	root			롼
.\"WORD:	super-user		ѡ桼
.\"
.TH SETUID 2 2004-05-27 "Linux" "Linux Programmer's Manual"
.SH ̾
setuid \- 桼 (identity) ꤹ
.SH 
.B #include <sys/types.h>
.br
.B #include <unistd.h>
.sp
.BI "int setuid(uid_t " uid );
.SH 
.BR setuid ()
ϸƤӽФΥץμ¸ (effective) 桼 ID ꤹ롣
⤷ƤӽФץμ¸ UID  root ʤС
 (real) UID ¸ (saved) set-user-ID ꤵ롣
.PP
Linux Ǥϡ
.BR setuid ()

.B _POSIX_SAVED_IDS
ä POSIX ǤΤ褦˼Ƥ롣
 (롼Ȱʳ) set-user-ID ץˤΥ桼ø
ͿøɬפʤŻ򤷡μ¸桼 ID 
ˡǺƤ᤹Ȥ
.PP
桼롼 (root) ޤϥץब롼Ȥ set-user-ID ƤʤС
̤դʧ롣
.BR setuid ()
ؿϸƤӽФԤμ¸桼 ID å
줬ѡ桼ʤС
ץ˴ϢƤΥ桼 ID 
.I uid
ꤹ롣
줬Ԥʤ줿ˤϥץबƤӥ롼Ȥø뤳ȤϤǤʤ
.PP
Τ褦ˡset-user-ID-root ץϰŪ˥롼øͿ
롼ȤǤʤ褦˿񤦤ȤǤ줫
.BR setuid ()
ȤäƺƤӥ롼ø뤳ȤǤʤ褦ˤ롣
(POSIX ǤʤBSD) 
.BR seteuid (2)
ǹԤʤȤǤ롣
.SH ֤
 0 ֤롣顼ξ \-1 ֤졢
.I errno
Ŭڤꤵ롣
.SH 顼
.TP
.B EAGAIN
.I uid
ߤΥ桼 ID ȥޥå
.I uid
ˤäƥץ꥽
.B RLIMIT_NPROC
Ķ
.TP
.B EPERM
桼ø
(Linux Ǥ
.B CAP_SETUID
ѥӥƥ (capability) )
.I uid
ƤӽФץμ UID ޤ¸ set-user-ID Ȱפʤ
.SH 
SVr4, POSIX.1-2001.
4.4BSD ΥȤϴʸߴϤʤ
BSD Υϼ (real)¸ (saved)¸ (effective) ID Ƥꤹ롣
.\" SVr4 ˤ¾ EINVAL 顼ˤĤƤεҤ롣
.SH 
.SS Linux Ǥ
Linux ϥե롦ƥࡦ桼 ID γǰġ
̾ϼ¸桼 ID 
.BR setuid ()
ϸƤӽФΥץΥե롦ƥࡦ桼 ID ꤹ롣
.BR setfsuid (2)
⻲Ȥ뤳ȡ
.PP
.I uid
Τμ¸ uid ȰۤäƤ硢ץϥפ뤳Ȥ
ػߤ롣
.SH Ϣ
.BR getuid (2),
.BR seteuid (2),
.BR setfsuid (2),
.BR setreuid (2),
.BR capabilities (7),
.BR credentials (7)