[linuxjm/LDP_man-pages.git] / release / man2 / mprotect.2

.\" -*- nroff -*-
.\" Copyright (C) 2007 Michael Kerrisk <mtk.manpages@gmail.com>
.\" and Copyright (C) 1995 Michael Shields <shields@tembel.org>.
.\"
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.\" 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.\" manual page may be incorrect or out-of-date.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 author of this work.
.\"
.\" Modified 1996-10-22 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 1997-05-31 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 2003-08-24 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 2004-08-16 by Andi Kleen <ak@muc.de>
.\" 2007-06-02, mtk: Fairly substantial rewrites and additions, and
.\" a much improved example program.
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-06-01, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated and revised 2003-10-24, Suzuki Takashi.
.\" Updated & Modified 2005-02-08, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified 2005-10-15, Yuichi SATO
.\" Updated 2007-06-11, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.54
.\"
.\"WORD: bitwise-or             ¥Ó¥Ã¥È¤´¤È¤ÎÏÀÍýÏÂ
.\"WORD: protection             ¥¢¥¯¥»¥¹Êݸî
.\"WORD: read-only              Æɤ߼è¤êÀìÍÑ
.\"
.TH MPROTECT 2 2008-08-06 "Linux" "Linux Programmer's Manual"
.SH ̾Á°
mprotect \- ¥á¥â¥êÎΰè¤ÎÊݸî¤òÀßÄꤹ¤ë
.SH ½ñ¼°
.nf
.B #include <sys/mman.h>
.sp
.BI "int mprotect(const void *" addr ", size_t " len ", int " prot );
.fi
.SH ÀâÌÀ
.BR mprotect ()
¤Ï¡¢¶è´Ö [\fIaddr\fP,\ \fIaddr\fP+\fIlen\fP\-1] ¤Î¥¢¥É¥ì¥¹ÈϰϤò´Þ¤à
¸Æ¤Ó½Ð¤·¸µ¤Î¥×¥í¥»¥¹¤Î¥á¥â¥ê¥Ú¡¼¥¸¤Î¥¢¥¯¥»¥¹Êݸî¤òÊѹ¹¤¹¤ë¡£
.I addr
¤Ï¥Ú¡¼¥¸¶­³¦¤Ë°ìÃפ·¤Æ¤¤¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£

¸Æ¤Ó½Ð¤·¸µ¤Î¥×¥í¥»¥¹¤¬¥¢¥¯¥»¥¹Êݸî¤Ë°ãÈ¿¤¹¤ë¤è¤¦¤Ê¥á¥â¥ê¥¢¥¯¥»¥¹¤ò
¹Ô¤ª¤¦¤È¤¹¤ë¤È¡¢¥«¡¼¥Í¥ë¤Ï¥·¥°¥Ê¥ë
.B SIGSEGV
¤ò¤½¤Î¥×¥í¥»¥¹¤ËÂФ·¤ÆÀ¸À®¤¹¤ë¡£
.PP
.I prot
¤Ë¤Ï¡¢
.B PROT_NONE
¤«¡¢°Ê²¼¤Î¥ê¥¹¥È¤Î
.B PROT_NONE
°Ê³°¤ÎÃͤò¥Ó¥Ã¥ÈËè¤ÎÏÀÍýÏ (bitwize-or) ¤Ç»ØÄꤹ¤ë:
.TP 1.1i
.B PROT_NONE
¤½¤Î¥á¥â¥ê¤Ë¤ÏÁ´¤¯¥¢¥¯¥»¥¹¤Ç¤­¤Ê¤¤¡£
.TP
.B PROT_READ
¤½¤Î¥á¥â¥ê¤òÆɤ߼è¤ë¤³¤È¤¬¤Ç¤­¤ë¡£
.TP
.B PROT_WRITE
¤½¤Î¥á¥â¥ê¤òÊѹ¹¤Ç¤­¤ë¡£
.TP
.B PROT_EXEC
¤½¤Î¥á¥â¥ê¤Ï¼Â¹Ô²Äǽ¤Ç¤¢¤ë¡£
.\" FIXME
.\" Document PROT_GROWSUP and PROT_GROWSDOWN
.SH ÊÖ¤êÃÍ
À®¸ù¤·¤¿¾ì¹ç¡¢
.BR mprotect ()
¤Ï 0 ¤òÊÖ¤¹¡£¥¨¥é¡¼¤Î¾ì¹ç¤Ï \-1 ¤¬Ê֤ꡢ
.I errno
¤¬Å¬ÀÚ¤ËÀßÄꤵ¤ì¤ë¡£
.SH ¥¨¥é¡¼
.TP
.B EACCES
»ØÄꤵ¤ì¤¿¥¢¥¯¥»¥¹¤ò¥á¥â¥ê¤ËÀßÄꤹ¤ë¤³¤È¤¬¤Ç¤­¤Ê¤¤¡£
¤³¤ì¤Ï¡¢Î㤨¤Ð
¥Õ¥¡¥¤¥ë¤òÆɤ߼è¤êÀìÍѤÇ
.BR mmap (2)
¤·¤Æ¤ª¤ê¡¢¤½¤ÎÎΰè¤ËÂФ·¤Æ
.BR mprotect ()
¤ò¸Æ¤Ó½Ð¤·¤Æ
.B PROT_WRITE
¤ËÀßÄꤷ¤è¤¦¤È¤·¤¿¾ì¹ç¤ËȯÀ¸¤¹¤ë¡£
.TP
.B EINVAL
\fIaddr\fP ¤¬Í­¸ú¤Ê¥Ý¥¤¥ó¥¿¤Ç¤Ê¤¤¤«¡¢
¥·¥¹¥Æ¥à¤Î¥Ú¡¼¥¸¥µ¥¤¥º¤ÎÇÜ¿ô¤Ç¤Ê¤¤¡£
.\" Or: both PROT_GROWSUP and PROT_GROWSDOWN were specified in 'prot'.
.TP
.B ENOMEM
¥«¡¼¥Í¥ëÆâÉô¤Î¹½Â¤ÂΤò³ä¤êÅö¤Æ¤ë¤³¤È¤¬¤Ç¤­¤Ê¤«¤Ã¤¿¡£
.TP
.B ENOMEM
.RI [ addr ,
.IR addr + len ]
¤È¤¤¤¦ÈϰϤΥ¢¥É¥ì¥¹¤¬¥×¥í¥»¥¹¤Î¥¢¥É¥ì¥¹¶õ´Ö¤È¤·¤ÆÉÔÀµ¤Ç¤¢¤ë¤«¡¢
¤½¤ÎÈϰϤΥ¢¥É¥ì¥¹¤¬¥Þ¥Ã¥×¤µ¤ì¤Æ¤¤¤Ê¤¤ 1 ¤Ä°Ê¾å¤Î¥Ú¡¼¥¸¤ò»Ø¤·¤Æ¤¤¤ë
(¥«¡¼¥Í¥ë 2.4.19 ¤è¤êÁ°¤Ç¤Ï¡¢¤³¤Î¾õ¶·¤Ç¥¨¥é¡¼
.B EFAULT
¤¬´Ö°ã¤Ã¤ÆÀ¸À®¤µ¤ì¤Æ¤¤¤¿)¡£
.SH ½àµò
SVr4, POSIX.1-2001.
.\" SVr4 ¤Ç¤Ï¾¤Ë¥¨¥é¡¼¥³¡¼¥É EAGAIN ¤¬ÄêµÁ¤µ¤ì¤Æ¤¤¤ë¡£
.\" SVr4 ¤Î¥¨¥é¡¼¾ò·ï¤Ï Linux ¤Î¤â¤Î¤Ë¤­¤Á¤ó¤ÈÂбþ¤·¤Ê¤¤¡£
POSIX ¤Ç¤Ï¡¢
.BR mmap (2)
·Ðͳ¤Ç³ÍÆÀ¤·¤Æ¤¤¤Ê¤¤¥á¥â¥êÎΰè¤ËÂФ·¤Æ
.BR mprotect ()
¤ò¹Ô¤Ã¤¿¾ì¹ç¤Î
.BR mprotect ()
¤ÎÆ°ºî¤Ï̤ÄêµÁ¤Ç¤¢¤ë¤È¤µ¤ì¤Æ¤¤¤ë¡£
.SH Ãí°Õ
Linux ¤Ç¤Ï¡¢(¥«¡¼¥Í¥ë vsyscall Îΰè°Ê³°¤Î)
Ǥ°Õ¤Î¥×¥í¥»¥¹¥¢¥É¥ì¥¹¶õ´Ö¤ËÂФ·¤Æ
.BR mprotect ()
¤ò¸Æ¤Ó½Ð¤¹¤³¤È¤¬¡¢¾ï¤Ëµö¤µ¤ì¤Æ¤¤¤ë¡£
¤³¤ì¤ÏÆä˴û¸¤Î¥³¡¼¥É¥Þ¥Ã¥Ô¥ó¥°¤ò½ñ¤­¹þ¤ß²Äǽ¤Ë¤¹¤ë¤¿¤á¤Ë»È¤ï¤ì¤ë¡£

.B PROT_EXEC
¤¬
.B PROT_READ
¤È°Û¤Ê¤ë±Æ¶Á¤ò»ý¤Ä¤«Èݤ«¤Ï¡¢¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤È¥«¡¼¥Í¥ë¤Î¥Ð¡¼¥¸¥ç¥ó¤Ë°Í¸¤¹¤ë¡£
(i386 ¤Ê¤É¤Î) ¤¤¤¯¤Ä¤«¤Î¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤Ç¤Ï¡¢
.B PROT_WRITE
¤ò¥»¥Ã¥È¤¹¤ë¤È¡¢°ÅÌۤΤ¦¤Á¤Ë
.B PROT_READ
¤¬¥»¥Ã¥È¤µ¤ì¤ë¡£

POSIX.1-2001 ¤Ç¤Ï¡¢
.I prot
¤Ç»ØÄꤵ¤ì¤Æ¤¤¤Ê¤¤¥¢¥¯¥»¥¹¤òµö²Ä¤¹¤ë¼ÂÁõ¤òǧ¤á¤Æ¤¤¤ë¡£
¤¿¤À¤·¡¢ºÇÄã¸Â¡¢
.B PROT_WRITE
¤¬¥»¥Ã¥È¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¤Ë¤Î¤ß½ñ¤­¹þ¤ß¥¢¥¯¥»¥¹¤¬µö²Ä¤µ¤ì¡¢
.B PROT_NONE
¤¬¥»¥Ã¥È¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¤Ë¤Ï¥¢¥¯¥»¥¹¤Ïµö²Ä¤µ¤ì¤Ê¤¤ÅÀ¤À¤±¤Ï
Ëþ¤¿¤¹É¬Íפ¬¤¢¤ë¡£
.SH Îã
.\" sigaction.2 refers to this example
.PP
°Ê²¼¤Î¥×¥í¥°¥é¥à¤Ï¡¢¥á¥â¥ê¥Ú¡¼¥¸¤ò 4¤Ä³ÎÊݤ·¡¢¤½¤Î¤¦¤Á 3ÈÖÌܤΥڡ¼¥¸¤ò
Æɤ߹þ¤ßÀìÍѤËÀßÄꤹ¤ë¡£¤½¤Î¸å¤Ç¡¢³ÎÊݤ·¤¿Îΰè¤Î¥¢¥É¥ì¥¹¤Î¾®¤µ¤¤Êý¤«¤é
Â礭¤ÊÊý¤Ë¸þ¤«¤Ã¤Æ½çÈ֤˥Х¤¥ÈÃͤòÊѹ¹¤¹¤ë¥ë¡¼¥×¤ò¼Â¹Ô¤¹¤ë¡£

¥×¥í¥°¥é¥à¤ò¼Â¹Ô¤·¤¿¾ì¹ç¤Î°ìÎã¤ò°Ê²¼¤Ë¼¨¤¹¡£

.in +4n
.nf
.RB "$" " ./a.out"
Start of region:        0x804c000
Got SIGSEGV at address: 0x804e000
.fi
.SS ¥×¥í¥°¥é¥à¤Î¥½¡¼¥¹
\&
.in
.nf
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>

#define handle_error(msg) \\
    do { perror(msg); exit(EXIT_FAILURE); } while (0)

char *buffer;

static void
handler(int sig, siginfo_t *si, void *unused)
{
    printf("Got SIGSEGV at address: 0x%lx\\n",
            (long) si\->si_addr);
    exit(EXIT_FAILURE);
}

int
main(void)
{
    char *p;
    int pagesize;
    struct sigaction sa;

    sa.sa_flags = SA_SIGINFO;
    sigemptyset(&sa.sa_mask);
    sa.sa_sigaction = handler;
    if (sigaction(SIGSEGV, &sa, NULL) == \-1)
        handle_error("sigaction");

    pagesize = sysconf(_SC_PAGE_SIZE);
    if (pagesize == \-1)
        handle_error("sysconf");

    /* Allocate a buffer aligned on a page boundary;
       initial protection is PROT_READ | PROT_WRITE */

    buffer = memalign(pagesize, 4 * pagesize);
    if (buffer == NULL)
        handle_error("memalign");

    printf("Start of region:        0x%lx\\n", (long) buffer);

    if (mprotect(buffer + pagesize * 2, pagesize,
                PROT_NONE) == \-1)
        handle_error("mprotect");

    for (p = buffer ; ; )
        *(p++) = \(aqa\(aq;

    printf("Loop completed\\n");     /* Should never happen */
    exit(EXIT_SUCCESS);
}
.fi
.SH ´ØÏ¢¹àÌÜ
.BR mmap (2),
.BR sysconf (3)