.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\"                               1993 Michael Haardt, Ian Jackson.
.\" and Copyright (C) 2007 Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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.
.\"
.\" Modified 1993-07-21 Rik Faith (faith@cs.unc.edu)
.\" Modified 1994-08-21 by Michael Chastain (mec@shell.portal.com):
.\"   Removed note about old kernel (pre-1.1.44) using wrong id on path.
.\" Modified 1996-03-18 by Martin Schulze (joey@infodrom.north.de):
.\"   Stated more clearly how it behaves with symbolic links.
.\" Added correction due to Nick Duffek (nsd@bbc.com), aeb, 960426
.\" Modified 1996-09-07 by Michael Haardt:
.\"   Restrictions for NFS
.\" Modified 1997-09-09 by Joseph S. Myers <jsm28@cam.ac.uk>
.\" Modified 1998-01-13 by Michael Haardt:
.\"   Using access is often insecure
.\" Modified 2001-10-16 by aeb
.\" Modified 2002-04-23 by Roger Luethi <rl@hellgate.ch>
.\" Modified 2004-06-23 by Michael Kerrisk
.\" 2007-06-10, mtk, various parts rewritten, and added BUGS section.
.\"
.\" Japanese Version Copyright (c) 1997-1998 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-12-17, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified 1998-05-11, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2001-12-14, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2002-06-17, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2005-02-23, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2007-05-01, Akihiro MOTOKI, LDP v2.46
.\" Updated 2007-09-04, Akihiro MOTOKI, LDP v2.64
.\"
.\"WORD:	permission		
.\"WORD:	privileges		
.\"WORD:	user			桼
.\"WORD:	file system		ե롦ƥ
.\"WORD:	object			֥
.\"WORD:	symbolic link		ܥå
.\"WORD:	refer			Ȥ
.\"WORD:	mask			ޥ
.\"WORD:	path			ѥ
.\"WORD:	effective user-ID	¸桼ID
.\"WORD:	real user-ID		¥桼ID
.\"WORD:	uid			桼 ID
.\"WORD:	gid			롼 ID
.\"WORD:	directory		ǥ쥯ȥ
.\"WORD:	call			
.\"WORD:	kernel			ͥ
.\"WORD:	memory			
.\"WORD:	dangling		Τʤ
.\"
.TH ACCESS 2 2007-07-10 "Linux" "Linux Programmer's Manual"
.SH ̾
access \- եФ¥桼ǤΥå
.SH 
.nf
.B #include <unistd.h>
.sp
.BI "int access(const char *" pathname ", int " mode );
.fi
.SH 
.BR access ()
ϡƤӽФץե
.I pathname
˥Ǥ뤫ɤå롣
.I pathname
ܥå󥯤ξ硢ܥå󥯤Ÿ롣

.\" F_OK is defined as 0 on every system that I know of.
.I mode
ϥåԤꤹΤǡͤ
.BR F_OK 
.\" 䤬ΤäƤ뤹٤ƤΥƥ F_OK  0 Ƥ롣
⤷
.BR R_OK ", " W_OK ", " X_OK
 1İʾΥӥåñ̤¤鹽ޥǤ롣
.B F_OK
ϥե뤬¸ߤ뤫ɤΤߤ򸡺롣
.BR R_OK ", " W_OK ", " X_OK
ϡե뤬¸ߤơ줾ɤ߹ߡ񤭹ߡ¹ԤεĤ뤫
򸡺롣

åϡºݤԤݤ˻Ѥ¸ (effective) ID Ǥʤ
ƤӽФץ
.I " (real)"
UID 
.I " (real)"
GID ȤäƹԤ롣
ˤꡢset-user-ID ץǡץư桼θ¤
ñ˷ꤹ뤳ȤǤ롣

ƤӽФץøץ (Ĥޤꡢץμ UID  0) ξ硢
̾ΥեФ
.B X_OK
ΥåϡΥեνͭԡ롼ס¾ͤΤ줫
¹ԵĤͭˤʤäƤ롣
.SH ֤
(Ƥ׵ᤵ줿Ĥ줿)֤롣
顼ξ (ʤȤĤ
.I mode
׵ᤵ줿Ĥʤä䡢¾Υ顼)
\-1 ֤졢
.I errno
Ŭڤꤵ롣
.SH 顼
.BR access ()
ϰʲξ˼Ԥ롣
.TP
.B EACCES
׵ᤵ줿
Υե뼫Ȥ˵ݤ줿
.I pathname
ػޤǥǥ쥯ȥΤ줫Ф븡
(search permission) ʤä
.RB ( path_resolution (7)
⻲ȤΤ)
.TP
.B ELOOP
.I pathname
褹ݤܥå󥯤¿᤮롣
.TP
.B ENAMETOOLONG
.I pathname
Ĺ᤮롣
.TP
.B ENOENT
.I pathname
ѥΤ줫¸ߤʤ
Τʤ (dangling) ܥå󥯤ˤʤäƤ롣
.TP
.B ENOTDIR
.I pathname
Υǥ쥯ȥʬºݤˤϥǥ쥯ȥǤʤ
.TP
.B EROFS
ɤ߹ (read-only) Υե롦ƥФƽ񤭹ߵĤ
׵ᤷ
.PP
.BR access ()
ϰʲͳˤ꼺Ԥ뤳Ȥ롣
.TP
.B EFAULT
.I pathname
ǽʥɥ쥹֤γؤƤ롣
.TP
.B EINVAL
.I mode
ͤꤵ줿
.TP
.B EIO
I/O 顼ȯ
.TP
.B ENOMEM
ͥ˽ʬʥ꤬ʤ
.TP
.B ETXTBSY
¹ΥեФƽ񤭹ߤ׵ᤷ
.SH 
SVr4, 4.3BSD, POSIX.1-2001.
.SH 
.PP
.BR ٹ :
桼㤨
.BR open (2)
ˤ륢ǽɤ(ºݤ˹Ԥ)
.BR access ()
ȤäƥåΤϡƥۡθˤʤ롣
ʤʤå򤷤Ƥ
ºݤ˥եΥץ򤹤֤ûֳ֤ѤǤ뤫Ǥ롣
.BR ͳΤǡΥƥॳȤΤ򤱤٤Ǥ롣
.PP
.I mode
ǻꤵ줿̤Τ줫ĤǤݤȡ
Ȥ
.I mode
ǻꤵ줿¾Υ̤Ĥ줿ȤƤ⡢
.BR access ()
ϥ顼֤
.PP
POSIX.1-2001 Ǥϡ
ƤӽФץŬڤøäƤ
(Ĥޤꡢѡ桼ξ)
Ȥեμ¹ԵĥӥåȤåȤƤʤƤ
.B X_OK
ΥåȤ֤ǧƤ롣
.\" HPU-UX 11  Tru64 5.1 ϤΤ褦ˤʤäƤ롣
Linux ϤΤ褦ˤϤʤäƤʤ
.PP
.I pathname
Υץեåǥ쥯ȥƤФ
 (ʤ¹ԥ) Ĥ줿ˤΤߡ
եϥǽȤʤ롣
줫Υǥ쥯ȥ꤬ԲĤξ硢
ե뼫ȤΥĤ˴ؤ餺
.BR access ()
ϼԤ롣
.PP
ӥåȤΤߤå졢եμƤϥåʤ
äơǥ쥯ȥ꤬񤭹߲ǽȤʤäϡǥ쥯ȥ
ե뤳ȤǽʤȤ̣ΤǤꡢǥ쥯ȥ
եȤƽ񤭹ळȤǤ櫓ǤϤʤ
Ʊͤ DOS Υեϡּ¹ԲǽפȽǤ뤬
.BR execve (2)
ϼԤ
.PP
.BR access ()
ϡ UID ޥåԥ󥰤Ѥ NFS ե롦ƥǤ
ǽʤ⤷ʤʤʤ UID Υޥåԥ󥰤ϥС
Ԥʤ졢Υå򤹤륯饤ȤˤϸʤǤ롣
.SH Х
С 2.4 (Ȥ) Υͥˤϡѡ桼Ǥ
.B X_OK
Υåΰ˴̯롣
ǥ쥯ȥʳΥե
(桼롼ס¾ͤ) ƤΥƥˤĤ
¹ԵĤʤ硢
.BR access ()
Υå \-1 ֤Τ
.I mode

.B X_OK
ꤵ줿ȤǤ
.I mode

.B R_OK

.B W_OK
˻ꤵ줿ˤ
.BR access ()
 0 ֤
.\" εưϼλΤä褦Ǥ롣
(С 2.6.3 )  2.6 ϤΥͥ
2.4 ϤΥͥƱͤư򤹤롣

2.6.20 ΥͥǤϡ
ե뤬¸ߤե륷ƥ
.BR mount (2)
ݤ˻ꤵ줿
.B MS_NOEXEC
ե饰θ̤
.BR access ()
̵뤷Ƥ
ͥ 2.6.20 ʹߤǤϡ
.BR access ()
ϤΥե饰θ褦ˤʤäƤ롣
.SH Ϣ
.BR chmod (2),
.BR chown (2),
.BR faccessat (2),
.BR open (2),
.BR setgid (2),
.BR setuid (2),
.BR stat (2),
.BR eauidaccess (3),
.BR credentials (7),
.BR path_resolution (7)