[linuxjm/LDP_man-pages.git] / draft / man2 / chroot.2

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.\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992
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.\" which is licensed free of charge, as they might when working
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.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
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.\" Modified by Michael Haardt <michael@moria.de>
.\" Modified 1993-07-21 by Rik Faith <faith@cs.unc.edu>
.\" Modified 1994-08-21 by Michael Chastain <mec@shell.portal.com>
.\" Modified 1996-06-13 by aeb
.\" Modified 1996-11-06 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 1997-08-21 by Joseph S. Myers <jsm28@cam.ac.uk>
.\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" Japanese Version Copyright (c) 1996 Yosiaki Yanagihara
.\"         all rights reserved.
.\" Translated Mon Jun 24 14:29:55 JST 1996
.\"         by Yosiaki Yanagihara <yosiaki@bsd2.kbnes.nec.co.jp>
.\" Modified Sat Dec 13 23:29:07 JST 1997
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated & Modified Fri 6 Apr 2001
.\"         by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated & Modified Thu Dec 23 10:04:20 JST 2004
.\"         by Yuichi SATO <ysato444@yahoo.co.jp>
.\"
.TH CHROOT 2 2010-09-20 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.\"O chroot \- change root directory
.SH ̾Á°
chroot \- ¥ë¡¼¥È¡¦¥Ç¥£¥ì¥¯¥È¥ê¤òÊѹ¹¤¹¤ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <unistd.h>
.sp
.BI "int chroot(const char *" path );
.sp
.in -4n
.\"O Feature Test Macro Requirements for glibc (see
.\"O .BR feature_test_macros (7)):
glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
.RB ( feature_test_macros (7)
»²¾È):
.in
.sp
.BR chroot ():
.ad l
.RS 4
.PD 0
.TP 4
.\"O Since glibc 2.2.2:
glibc 2.2.2 °Ê¹ß:
.nf
_BSD_SOURCE ||
    (_XOPEN_SOURCE\ >=\ 500 ||
        _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED) &&
    !(_POSIX_C_SOURCE\ >=\ 200112L || _XOPEN_SOURCE\ >=\ 600)
.fi
.TP 4
.\"O Before glibc 2.2.2: none
glibc 2.2.2 ¤è¤êÁ°: ¤Ê¤·
.PD
.RE
.ad b
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O .BR chroot ()
.\"O changes the root directory of the calling process to that specified in
.\"O .IR path .
.\"O This directory will be used for pathnames beginning with \fI/\fP.
.\"O The root directory is inherited by all children of the calling process.
.BR chroot ()
¤Ï¡¢¸Æ¤Ó½Ð¤·¸µ¥×¥í¥»¥¹¤Î¥ë¡¼¥È¡¦¥Ç¥£¥ì¥¯¥È¥ê¤ò
.I path
¤Ç»ØÄꤵ¤ì¤¿¥Ç¥£¥ì¥¯¥È¥ê¤ËÊѹ¹¤¹¤ë¡£
¤³¤Î¥Ç¥£¥ì¥¯¥È¥ê°Ê²¼¤¬ \fI/\fP ¤«¤é»Ï¤Þ¤ë¥Ñ¥¹Ì¾¤È¤·¤Æ»È¤ï¤ì¤ë¡£
¤³¤Î¥ë¡¼¥È¡¦¥Ç¥£¥ì¥¯¥È¥ê¤Ï¸Æ¤Ó½Ð¤·¸µ¤Î¥×¥í¥»¥¹¤ÎÁ´¤Æ¤Î»Ò¥×¥í¥»¥¹¤Ë¼õ¤±·Ñ¤¬¤ì¤ë¡£
.\"O 
.PP
.\"O Only a privileged process (Linux: one with the
.\"O .B CAP_SYS_CHROOT
.\"O capability) may call
.\"O .BR chroot ().
Æø¢¥×¥í¥»¥¹ (Linux ¤Ç¤Ï¡¢
.B CAP_SYS_CHROOT
¥±¡¼¥Ñ¥Ó¥ê¥Æ¥£¤ò»ý¤Ä¥×¥í¥»¥¹) ¤Î¤ß¤¬
.BR chroot ()
¤ò¸Æ¤Ó½Ð¤¹¤³¤È¤¬¤Ç¤­¤ë¡£
.\"O 
.PP
.\"O This call changes an ingredient in the pathname resolution process
.\"O and does nothing else.
¤³¤Î¥³¡¼¥ë¤Ï¥Ñ¥¹Ì¾²ò·è¤Î²áÄø¤Ç¹½À®Í×ÁǤòÊѹ¹¤¹¤ë¤Î¤ß¤Ç¡¢
¤½¤Î¾¤Ë¤Ï²¿¤â¹Ô¤ï¤Ê¤¤¡£
.\"O 
.PP
.\"O This call does not change the current working directory,
.\"O so that after the call \(aq\fI.\fP\(aq can
.\"O be outside the tree rooted at \(aq\fI/\fP\(aq.
.\"O In particular, the superuser can escape from a "chroot jail"
.\"O by doing:
¤³¤Î¥³¡¼¥ë¤Ï¸½ºß¤Îºî¶È¥Ç¥£¥ì¥¯¥È¥ê
(working directory) ¤òÊѹ¹¤·¤Ê¤¤¡£
¤½¤Î¤¿¤á¡¢¤³¤Î¥³¡¼¥ë¤Î¸å¤Ë \(aq\fI.\fP\(aq ¤¬ \(aq\fI/\fP\(aq ¤ò
º¬¤È¤¹¤ë¥Ä¥ê¡¼¤Î³°¤Ë¤Ê¤ë¾ì¹ç¤¬¤¢¤ë¡£
Æäˡ¢¥¹¡¼¥Ñ¡¼¡¦¥æ¡¼¥¶¡¼¤Ï°Ê²¼¤Î¤è¤¦¤Ë¤¹¤ë¤³¤È¤Ç
"chroot jail" ¤«¤éƨ¤²½Ð¤»¤Æ¤·¤Þ¤¦¡£
.nf

    mkdir foo; chroot foo; cd ..
.fi

.\"O This call does not close open file descriptors, and such file
.\"O descriptors may allow access to files outside the chroot tree.
¤³¤Î¥³¡¼¥ë¤Ï¥ª¡¼¥×¥ó¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤ò¥¯¥í¡¼¥º¤·¤Ê¤¤¤Î¤Ç¡¢
¤³¤Î¤è¤¦¤Ê¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ï chroot ¥Ä¥ê¡¼¤Î³°¤Ë¤¢¤ë
¥Õ¥¡¥¤¥ë¤Ë¥¢¥¯¥»¥¹¤Ç¤­¤ë¡£
.\"O .SH "RETURN VALUE"
.SH ÊÖ¤êÃÍ
.\"O On success, zero is returned.
.\"O On error, \-1 is returned, and
.\"O .I errno
.\"O is set appropriately.
À®¸ù¤¹¤ë¤È 0 ¤òÊÖ¤¹¡£
¼ºÇÔ¤¹¤ë¤È \-1 ¤òÊÖ¤·¡¢
.I errno
¤ËŬÀÚ¤ÊÃͤòÀßÄꤹ¤ë¡£
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.\"O Depending on the file system, other errors can be returned.
.\"O The more general errors are listed below:
¥Õ¥¡¥¤¥ë¥·¥¹¥Æ¥à¤Ë¤è¤Ã¤Æ¤Ï¾¤Î¥¨¥é¡¼¤¬ÊÖ¤µ¤ì¤ë»ö¤¬¤¢¤ë¡£
°ìÈÌŪ¤Ê¥¨¥é¡¼¤ò°Ê²¼¤Ëµó¤²¤ë:
.TP
.B EACCES
.\"O Search permission is denied on a component of the path prefix.
¥Ñ¥¹Ì¾¤ÎÅÓÃæ¤Î¤É¤³¤«¤Ë¸¡º÷µö²Ä (search permission) ¤¬¤Ê¤¤¡£
.\"O (See also
.\"O .BR path_resolution (7).)
.RB ( path_resolution (7)
¤â»²¾È¤¹¤ë¤³¤È¡£)
.\"O .\" Also search permission is required on the final component,
.\"O .\" maybe just to guarantee that it is a directory?
.\" ¥Ñ¥¹Ì¾¤ÎºÇ¸å¤Î¹½À®Í×ÁǤˤ⸡º÷µö²Ä¤¬É¬ÍפǤ¢¤ë¡£
.\" ¤ª¤½¤é¤¯¡¢¤½¤ì¤¬¥Ç¥£¥ì¥¯¥È¥ê¤Ç¤¢¤ë¤³¤È¤òÊݾڤ¹¤ë¤¿¤á¤Ê¤Î¤«?
.TP
.B EFAULT
.\"O .I path
.\"O points outside your accessible address space.
.I path
¤¬³ä¤êÅö¤Æ¤é¤ì¤¿¥¢¥É¥ì¥¹¶õ´Ö³°¤ò»Ø¤·¤Æ¤¤¤ë¡£
.TP
.B EIO
.\"O An I/O error occurred.
I/O ¥¨¥é¡¼¤¬È¯À¸¤·¤¿¡£
.TP
.B ELOOP
.\"O Too many symbolic links were encountered in resolving
.\"O .IR path .
.I path
¤ò²ò·è¤¹¤ëºÝ¤ËÁø¶ø¤·¤¿¥·¥ó¥Ü¥ê¥Ã¥¯¡¦¥ê¥ó¥¯¤¬Â¿²á¤®¤ë¡£
.TP
.B ENAMETOOLONG
.\"O .I path
.\"O is too long.
.I path
¤¬Ä¹²á¤®¤ë¡£
.TP
.B ENOENT
.\"O The file does not exist.
¥Õ¥¡¥¤¥ë¤¬Â¸ºß¤·¤Ê¤¤¡£
.TP
.B ENOMEM
.\"O Insufficient kernel memory was available.
¥«¡¼¥Í¥ë¤Ë½½Ê¬¤Ê¥á¥â¥ê¤¬¤Ê¤¤¡£
.TP
.B ENOTDIR
.\"O A component of
.\"O .I path
.\"O is not a directory.
.I path
¤ÎÆâÍƤ¬¥Ç¥£¥ì¥¯¥È¥ê¤Ç¤Ï¤Ê¤¤¡£
.TP
.B EPERM
.\"O The caller has insufficient privilege.
¸Æ¤Ó½Ð¤·Â¦¤Ë½½Ê¬¤ÊÆø¢¤¬¤Ê¤¤¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
.\"O SVr4, 4.4BSD, SUSv2 (marked LEGACY).
.\"O This function is not part of POSIX.1-2001.
.\"O .\" SVr4 documents additional EINTR, ENOLINK and EMULTIHOP error conditions.
.\"O .\" X/OPEN does not document EIO, ENOMEM or EFAULT error conditions.
SVr4, 4.4BSD, SUSv2 (⤷¡¢SUSv2 ¤Ç¤Ï²áµî¤Î̾»Ä¤È¤µ¤ì¤Æ¤¤¤ë)¡£
¤³¤Î´Ø¿ô¤Ï POSIX.1-2001 ¤Ë¤Ï¤Ê¤¤¡£
.\" SVr4 ¤Ë¤Ï¾¤Ë EINTR, ENOLINK, EMULTIHOP ¥¨¥é¡¼¾õÂ֤ˤĤ¤¤Æ¤Îµ­½Ò¤¬¤¢¤ë¡£
.\" X/OPEN ¤Ë¤Ï EIO, ENOMEM, EFAULT ¥¨¥é¡¼¾õÂ֤ε­½Ò¤Ï¤Ê¤¤¡£
.\"O .SH NOTES
.SH Ãí°Õ
.\"O A child process created via
.\"O .BR fork (2)
.\"O inherits its parent's root directory.
.\"O The root directory is left unchanged by
.\"O .BR execve (2).
.BR fork (2)
¤ÇºîÀ®¤µ¤ì¤¿»Ò¥×¥í¥»¥¹¤Ï¡¢
¿Æ¥×¥í¥»¥¹¤Î¥ë¡¼¥È¡¦¥Ç¥£¥ì¥¯¥È¥ê¤ò·Ñ¾µ¤¹¤ë¡£
.BR execve (2)
¤Î¾ì¹ç¤â¡¢¥ë¡¼¥È¡¦¥Ç¥£¥ì¥¯¥È¥ê¤ÏÊѹ¹¤µ¤ì¤Ê¤¤¡£

.\"O FreeBSD has a stronger
.\"O .BR jail ()
.\"O system call.
FreeBSD ¤Ë¤Ï¤è¤ê¶¯ÎϤÊ
.BR jail ()
¥·¥¹¥Æ¥à¥³¡¼¥ë¤¬¤¢¤ë¡£
.\" FIXME . eventually say something about containers,
.\" virtual servers, etc.?
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR chdir (2),
.BR path_resolution (7)