.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright (C) 1996 Andries Brouwer <aeb@cwi.nl>
.\" and Copyright (C) 2006, 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.\" manual page may be incorrect or out-of-date.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 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2000-03-25 by Jim Van Zandt <jrv@vanzandt.mv.com>
.\" Modified 2001-10-04 by John Levon <moz@compsoc.man.ac.uk>
.\" Modified 2003-02-02 by Andi Kleen <ak@muc.de>
.\" Modified 2003-05-21 by Michael Kerrisk <mtk.manpages@gmail.com>
.\"	MAP_LOCKED works from 2.5.37
.\" Modified 2004-06-17 by Michael Kerrisk <mtk.manpages@gmail.com>
.\" Modified 2004-09-11 by aeb
.\" Modified 2004-12-08, from Eric Estievenart <eric.estievenart@free.fr>
.\" Modified 2004-12-08, mtk, formatting tidy-ups
.\" Modified 2006-12-04, mtk, various parts rewritten
.\" 2007-07-10, mtk, Added an example program.
.\"
.\" Japanese Version Copyright (c) 1997-2000 SUTO, Mitsuaki and NAKANO Takeo
.\"         all rights reserved.
.\" Translated 1997-06-26, SUTO, Mitsuaki <suto@av.crl.sony.co.jp>
.\" Updated & Modified 1999-03-01, NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated 2000-10-12, Nakano Takeo
.\" Updated 2001-08-16, Nakano Takeo
.\" Updated 2001-11-11, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2002-08-13, Akihiro MOTOKI
.\" Updated 2003-07- 2, Akihiro MOTOKI
.\" Updated 2003-09-14, Akihiro MOTOKI
.\" Updated & Modified 2004-12-28, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated 2005-09-06, Akihiro MOTOKI
.\" Updated 2005-10-05, Akihiro MOTOKI
.\" Updated 2006-07-23, Akihiro MOTOKI, LDP v2.36
.\" Updated 2007-01-07, Akihiro MOTOKI, LDP v2.43
.\" Updated 2007-05-04, Akihiro MOTOKI, LDP v2.46
.\" Updated 2007-09-03, Akihiro MOTOKI, LDP v2.64
.\"
.\"WORD		file descriptor		ե뵭һ
.\"
.TH MMAP 2 2007-11-25 "Linux" "Linux Programmer's Manual"
.SH ̾
mmap, munmap \- եǥХ˥ޥå/ޥåפ
.SH 
.nf
.B #include <sys/mman.h>
.sp
.BI "void *mmap(void *" start ", size_t " length \
", int " prot ", int " flags ,
.BI "           int " fd ", off_t " offset );
.BI "int munmap(void *" start ", size_t " length );
.fi
.SH 
.BR mmap ()
ϡޥåԥ󥰤ƤӽФץβۥɥ쥹֤˺롣
ޥåԥ󥰤γϥɥ쥹
.I start
ǻꤵ롣ޥåԥ󥰤Ĺ
.I length
ǻꤵ롣

.I start
 NULL ξ硢ͥ뤬ޥåԥ󥰤륢ɥ쥹򤹤롣
ˡϺǤܿΤ뿷ޥåԥ󥰤κˡǤ롣
.I start
 NULL Ǥʤ硢ͥϥޥåԥ󥰤ɤ֤뤫ΥҥȤȤ
.I start
Ѥ롣Linux Ǥϡޥåԥ󥰤 (ɥ쥹礭ʤ)
Υڡ˺롣
ޥåԥ󥰤Υɥ쥹ϡƤӽФ֤ͤȤ֤롣

եޥåԥ󥰤Ƥϡ
եǥץ
.I fd
ǻȤե (⤷¾Υ֥) Υեå
.I offset
鳫Ϥ
.I length
ХȤΥǡǽ
(եޥåԥ󥰤̵̾ޥåԥ󥰤ȿиǤ롣
.B MAP_ANONYMOUS
򻲾)
.I offset

.I sysconf(_SC_PAGE_SIZE)
֤ڡܿǤʤФʤʤ
.LP

.I prot
ˤϡޥåԥ󥰤ΥݸɤΤ褦˹Ԥʤꤹ
(եΥץ⡼ɤ̷⤷ƤϤʤ)
.I prot
ˤϡ
.B PROT_NONE
ʲΥե饰ҤȤİʾӥå (OR) ȤäΤ
Ǥ롣
.TP 1.1i
.B PROT_EXEC
ڡϼ¹ԲǽǤ롣
.TP
.B PROT_READ
ڡɤ߹߲ǽǤ롣
.TP
.B PROT_WRITE
ڡ˽񤭹߲ǽǤ롣
.TP
.B PROT_NONE
ڡˤϥǤʤ
.LP
.I flags
ˤꡢޥåԥ󥰤Ф빹Ʊΰޥåԥ󥰤Ƥ
¾Υץ˸뤫ޥåԥ󥰸Υե̤
뤫ꤵ롣ưϡʲͤΤ줫Ĥ
(ʣϻǤʤ) 
.I flags
˴ޤ뤳Ȥǻꤹ롣
.TP 1.1i
.B MAP_SHARED
Υޥåԥ󥰤ͭ롣
ޥåԥ󥰤Ф빹ϤΥեޥåԥ󥰤Ƥ¾Υץ
鸫롣ϥޥåԥ󥰸Υե̤롣
եμºݤι
.BR msync (2)
ޤ
.BR munmap ()
ƤФޤǹԤʤȤ⤢롣
.TP
.B MAP_PRIVATE
ץ饤١Ȥ copy-on-write (񤭹߻ԡ) ޥåפ롣
ޥåԥ󥰤Ф빹Ʊեޥåԥ󥰤Ƥ¾Υץ
ˤϸޥåԥ󥰸Υե̤뤳Ȥʤ
.BR mmap ()
θƤӽФ˥ޥåԥ󥰸ΥեФƹԤ줿ѹ
ޥåΰȿǤ뤫ɤϵꤵƤʤ
.LP
嵭ĤΥե饰 POSIX.1-2001 ǵꤵƤ롣

ˡʲͤΤ 0 İʾӥå (OR) 
.I flags
˻ꤹ뤳ȤǤ롣
.TP
.B MAP_32BIT
ޥåԥ󥰤ץΥɥ쥹֤Ƭ 2GB ϰϤ֤롣
.B MAP_FIXED
åȤƤϡΥե饰̵뤵롣
ߤΤȤΥե饰ݡȤƤΤϡx86-64 ƥ
 64 ӥåȡץˤĤƤΤߤǤ롣
.TP
.B MAP_ANON
.B MAP_ANONYMOUS
Ʊ졣侩
.TP
.B MAP_ANONYMOUS
ޥåԥ󥰤ϤɤΥեȤϢդʤ
ޥåԥ󥰤Ƥ 0 ǽ롣

.I fd

.I offset
̵뤵롣
ˤäƤ
.B MAP_ANONYMOUS
(⤷
.BR MAP_ANON )
ꤵ줿硢
.I fd
 \-1 ˤɬפꡢ
ܿɬפʥץꥱǤɬ
.I fd
 \-1 ˤ٤Ǥ롣
.B MAP_ANONYMOUS

.B MAP_SHARED
Ȥ߹碌ƤѤ
ͥ 2.4 ʹߤ Linux ǤΤߥݡȤƤ롣
.TP
.B MAP_DENYWRITE
Υե饰̵뤵
.\" 1.1.36 Ƴ졢1.3.24 Ǻ줿
(äϡޥå׸Υեؤν񤭹ߤԤȤȡ顼
.B ETXTBUSY
ǼԤ褦˥ʥ뤬ꤵƤ denial-of-service
(ӥ) θȤʤä)
.TP
.B MAP_EXECUTABLE
Υե饰̵뤵롣
.\" 1.1.38 Ƴ졢1.3.24 Ǻ줿
.\" proc_follow_link ǥƥȤե饰Ǥ롣(äϡ
.\" ޥå׸Υե뤬¹ԲǽǤ뤳ȤΤ餻褦ˤʤäƤ
.\" ξϼºݤˤϤɤǤȤʤä)
.\" Linus  MAP_EXECUTABLE ˴Ϣ DoS ä򤷤
.\" MAP_DENYWRITE ΤȤͤƤΤʡ
.TP
.B MAP_FILE
ߴΤΥե饰̵뤵롣
.\" On some systems, this was required as the opposite of
.\" MAP_ANONYMOUS -- mtk, 1 May 2007
.TP
.B MAP_FIXED
.I start
򥢥ɥ쥹ΥҥȤȤƻѤΤǤϤʤ
.I start
ǻꤵ줿ɥ쥹򤽤Τޤ޻Ѥƥޥåԥ󥰤֤롣
.I start
ϥڡܿǤʤФʤʤ
.I start

.I len
ǻꤵ줿ΰ褬¸Υޥåԥ󥰤ΥڡȽŤʤ硢
¸Υޥåԥ󥰤νŤʤäʬϼΤƤ롣
⤷ꤵ줿ɥ쥹ѤǤʤ硢
.BR mmap ()
ϼԤ롣
ޥåԥ󥰤ФƸꥢɥ쥹׵᤹Τϰ̤ܿΤǡ
ΥץϻѤʤȤ侩롣
.TP
.B MAP_GROWSDOWN
åѤ˻Ѥ롣ޥåԥ󥰤ǵո˹ԤȤ
ͥ벾ۥꥷƥ˻ؼ롣
(ޥåԥ󥰤̾ϥꡦɥ쥹ä˹Ԥ
Υץꤹȵո˥ޥåԥ󥰤Ԥ)
.TP
.BR MAP_LOCKED " (Linux 2.5.37 ʹ)"
ޥåפ줿ΰΥڡ
.BR mlock (2)
ˡǥ˥å롣
ΥͥǤϡΥե饰̵뤵롣
.\" Υե饰åȤƤȡޥåԥ󥰤줿ڡϥåץ
.\" ʤ
.TP
.BR MAP_NONBLOCK " (Linux 2.5.46 ʹ)"
.B MAP_POPULATE
Ȥ߹碌Τ̣߰ġ
read-ahead (äɤ߹ळ) ¹Ԥʤ
ñˡǤ RAM ¸ߤڡФ
ڡơ֥륨ȥǤ롣
.TP
.B MAP_NORESERVE
Υޥåԥ󥰤Ф륹å׶֤ͽԤʤ
å׶֤ͽ󤷤ϡΥޥåԥ󥰤ѹɬǽʤȤ
ݾڤ롣ͽԤʤä硢ʪ˶ʤ
񤭹߻
.B SIGSEGV
顼뤳Ȥ롣
.BR proc (5)

.I /proc/sys/vm/overcommit_memory
եˤĤƤε⻲ȡ
С 2.6 ΥͥǤϡΥե饰Ͻ񤭹߲ǽ
ץ饤١ȡޥåԥ󥰤ˤĤƤΤ߸̤ä
.TP
.BR MAP_POPULATE " (Linux 2.5.46 ʹ)"
եäɤ߹ (read-ahead) Ȥǡ
եޥåԥѤΥڡơ֥ (populate) 
(äƥڡեȤ (prefault))
θϡޥåԥ󥰤Ф륢ڡեȤ
֥åʤʤ롣
.LP
嵭Υե饰Ǥϡ
.B MAP_FIXED
 POSIX.1-2001 ǵꤵƤ롣
ʤ顢ۤȤɤΥƥ
.B MAP_ANONYMOUS
(ޤϤƱǤ
.BR MAP_ANON )
⥵ݡȤƤ롣
.LP
ĤΥƥǤϡ嵭ʳ˥ե饰Ȥ
.BR MAP_AUTOGROW ,
.BR MAP_AUTORESRV ,
.BR MAP_COPY ,
.B MAP_LOCAL
ꤵƤ롣
.LP
.BR mmap ()
ˤäƥޥåפ줿°
.BR fork (2)
κݤ˷Ѿ롣
.LP
եϥڡܤΰ˥ޥåפ롣ڡ
ܤǤʤեξ硢ޥå׻˻Ĥΰ 0 졢ΰ
񤭤ߤԤäƤե˽񤭽Ф뤳ȤϤʤޥåԥ󥰤Ԥä
եΥѹ硢եɲä줿줿ΰб
ޥåפ줿ڡФƤɤΤ褦ʱƶ뤫ϵꤵƤʤ
ƥॳ
.BR munmap ()
ϻꤵ줿ɥ쥹ϰϤΥޥåפõ
ʹߤΤϰؤΥ껲ȤȤʤ롣
ΰϡץλȤˤ⼫ưŪ˥ޥåפ롣
ե뵭һҤ򥯥Ƥ⡢ΰϥޥåפʤ
.LP
.I start
ɥ쥹ϥڡܤǤʤФʤʤꤵ줿ϰϤΰʬ
ޤƤΥڡϥޥåפ졢ʹߤˤΥڡؤλȤ
.B SIGSEGV
ȯ롣
ꤷϰ˥ޥåפ줿ڡĤޤޤƤʤǤ
顼ˤʤʤ
եȴϢդ줿ޥåԥ󥰤ξ硢ޥåԥ󥰤줿ե
.I st_atime
եɤϡ
.BR mmap ()
Ƥ饢ޥå (unmap) ޤǤδ֤˹뤳Ȥ롣
ޤǤ˹ԤƤʤСޥåפ줿ڡؤκǽλȤä
ݤ˹롣
.LP
.B PROT_WRITE

.B MAP_SHARED
ξꤷƥޥåפ줿եξ硢񤭹ߤȡ
.I st_ctime

.I st_mtime
ξեɤϡޥåפ줿ΰؤν񤭹ߤǡ
.B MS_SYNC
ޤ
.B MS_ASYNC
ե饰ꤷ
.BR msync (2)
ƤФޤǤ˹롣
.SH ֤
.BR mmap ()
ȥޥåפ줿ΰؤΥݥ󥿤֤
Ԥ
.B MAP_FAILED
(Ĥޤ
.IR "(void\ *)\ \-1" )
֤
.I errno
顼ƤˤäƥåȤ롣
.BR munmap ()
 0 ֤Ԥ \-1 ֤
.I errno
åȤ (¿ξ
.B EINVAL
ˤʤ)
.SH 顼
.TP
.B EACCES
ʲΤ줫ξ硣
ե뵭һҤλ褬̾ΥեǤϤʤ (non-regular file) 
.B MAP_PRIVATE
׵ᤷ
.I fd
ɤ߹Ѥ˥ץ󤵤Ƥʤ
.B MAP_SHARED
׵ᤷ
.B PROT_WRITE
򥻥åȤ
.I fd
ɤ߽񤭥⡼
.RB ( O_RDWR )
ǥץ󤵤Ƥʤ
.B PROT_WRITE
򥻥åȤեɲ (append) ѤǤ롣
.TP
.B EAGAIN
ե뤬åƤ롣ޤϥåƤ꤬¿
.RB ( setrlimit (2)
򻲾)
.TP
.B EBADF
.I fd
ͭʥե뵭һ (file descriptor) ǤϤʤ
(
.B MAP_ANONYMOUS
åȤƤʤ)
.TP
.B EINVAL
.I start

.I length

.I offset
ŬڤǤʤ
(㤨С礭Ȥڡ˥饤ȤƤʤ)
.TP
.B EINVAL
(Linux 2.6.12 ʹ)
.I length
 0 Ǥä
.TP
.B EINVAL
.I flags

.B MAP_PRIVATE

.B MAP_SHARED
ΤɤޤޤƤʤä⤷
ξޤޤƤ
.TP
.B ENFILE
.\" ϶ͭƿ̾ (anonymous) ȤΤΤΤǤ롣
.\" [2.6.7] shmem_zero_setup()-->shmem_file_setup()-->get_empty_filp()
ץ󤵤줿եƥ¤ã
.\" .TP
.\" .B ENOEXEC
.\" եɤ߹Ѥ˥ޥåפǤʤä
.TP
.B ENODEV
ꤵ줿ե뤬֤Ƥե륷ƥबޥåԥ󥰤򥵥ݡ
Ƥʤ
.TP
.B ENOMEM
˶ʤޤϽΥץΥޥåԥ󥰿Ķᤷ
.TP
.B EPERM
.I prot

.B PROT_EXEC
Ԥ褦˻ꤵƤ뤬
no-exec ǥޥȤ줿ե륷ƥΥե
ޥåΰ褬бƤ롣
.\" (2.4.25 / 2.6.0 ʹ)
.TP
.B ETXTBSY
.B MAP_DENYWRITE
åȤƤ뤬
.I fd
ǻꤵƤ륪֥ȤϽ񤭹Ѥ˳Ƥ롣
.LP
ޥåΰѤݤˡʲΥʥ뤬ȯ뤳Ȥ:
.TP
.B SIGSEGV
ɤ߹Ѥ mmap 줿ΰؽ񤭹ߤԤȤ
.TP
.B SIGBUS
ХåեΤե˴ϢŤƤʤʬ
(㤨Хեۤʬʤɡˤ
¾Υץեڤͤ᤿ʤɤޤޤ)
˥褦Ȥ
.SH 
SVr4, 4.4BSD, POSIX.1-2001.
.\" SVr4 ˤϤ ENXIO  ENODEV Υ顼ɤˤĤƤεҤ롣
.\" SUSv2 ˤϤ EMFILE  EOVERFLOW Υ顼ɤˤĤƤεҤ롣
.SH 
.BR mmap (),
.BR msync (2)
.BR munmap ()
Ѳǽ POSIX ƥǤϡ
.B _POSIX_MAPPED_FILES
 <unistd.h>  0 礭ͤ
.RB ( sysconf (3)
⻲ȤΤ)
.\" POSIX.1-2001: _POSIX_MAPPED_FILES  -1  0  200112L 
.\" 줫뤳ȤˤʤäƤ롣
.\" -1: Բġ0: sysconf() 䤤碌
.\" glibc Ǥ POSIX_MAPPED_FILES  1 Ƥ롣
.SH 
ͥ 2.4 ʹߡΥƥॳ
.BR mmap2 (2)
˼ä줿
ߤǤϡ
.\" ץåȥեˤۤʤ뤬 glibc 2.1/2.2 ꤫顣
glibc 
.BR mmap ()
Υåѡؿ
.I offset
ŬڤĴƤ
.BR mmap2 (2)
ư롣

(i386 ʤɤ) ĤΥƥǤϡ
.B PROT_WRITE
򥻥åȤȡۤΤ
.B PROT_READ
åȤ롣
.B PROT_READ
򥻥åȤݤ˰ۤΤ
.B PROT_EXEC
åȤ뤫ɤϡƥ¸Ǥ롣
ܿθץǤϡ
˥ޥåפΰǥɤ¹Ԥϡ
.B PROT_EXEC
򥻥åȤ٤Ǥ롣
.SH Х
Linux ˤƤϡ嵭
.B MAP_NORESERVE
ǽҤ٤Ƥ褦ݾڤϤʤ
ǥեȤǤϡƥबȤڤäˤϡ
ɤΥץĶλ뤫ʬʤǤ롣

2.6.7 ΥͥǤϡ
.I prot

.B PROT_NONE
ꤵ줿ˤΤߡ
.B MAP_POPULATE
ե饰Ϥġ

SUSv3 Ǥϡ
.I length
 0 ξ硢
.BR mmap ()
ϼԤȵꤵƤ롣ʤ顢2.6.12 ΥͥǤϡ
ξ
.BR mmap ()
Ƥ (ޥåԥ󥰤Ϻ줺
.I start
֤Ƥ)
ͥ 2.6.12 ʹߤǤϡ
.BR mmap ()
ϥ顼
.B EINVAL
ǼԤ롣
.SH 
.PP
ʲΥץϡܤΥޥɥ饤ǻꤵ줿
եΰɸϤɽ롣
ɽϰϤϡܡܤΥޥɥ饤Ϥ
եåȤĹǻꤵ롣
Υץϡꤵ줿եɬפʥڡΥꡦ
ޥåԥ󥰤
.BR write (2)
Ȥäƽ˾ΥХȤϤ롣
.nf

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

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

int
main(int argc, char *argv[])
{
    char *addr;
    int fd;
    struct stat sb;
    off_t offset, pa_offset;
    size_t length;
    ssize_t s;

    if (argc < 3 || argc > 4) {
        fprintf(stderr, "%s file offset [length]\\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    fd = open(argv[1], O_RDONLY);
    if (fd == \-1)
        handle_error("open");

    if (fstat(fd, &sb) == \-1)           /* To obtain file size */
        handle_error("fstat");

    offset = atoi(argv[2]);
    pa_offset = offset & ~(sysconf(_SC_PAGE_SIZE) \- 1);
        /* offset for mmap() must be page aligned */

    if (offset >= sb.st_size) {
        fprintf(stderr, "offset is past end of file\\n");
        exit(EXIT_FAILURE);
    }

    if (argc == 4) {
        length = atoi(argv[3]);
        if (offset + length > sb.st_size)
            length = sb.st_size \- offset;
                /* Can't display bytes past end of file */

    } else {    /* No length arg ==> display to end of file */
        length = sb.st_size \- offset;
    }

    addr = mmap(NULL, length + offset \- pa_offset, PROT_READ,
                MAP_PRIVATE, fd, pa_offset);
    if (addr == MAP_FAILED)
        handle_error("mmap");

    s = write(STDOUT_FILENO, addr + offset \- pa_offset, length);
    if (s != length) {
        if (s == \-1)
            handle_error("write");

        fprintf(stderr, "partial write");
        exit(EXIT_FAILURE);
    }

    exit(EXIT_SUCCESS);
} /* main */
.fi
\"O .SH "SEE ALSO"
.SH Ϣ
.BR getpagesize (2),
.BR mincore (2),
.BR mlock (2),
.BR mmap2 (2),
.BR mremap (2),
.BR msync (2),
.BR remap_file_pages (2),
.BR setrlimit (2),
.BR shm_open (3)
.br
B.O. Gallmeister, POSIX.4, O'Reilly, pp. 128-129 and 389-391.
.\"
.\" θˤĤƸäƤߤ: ץ饤١Ȥɤ߹ѤΥޥåԥ󥰤
.\" ͭ줿ɤ߹ѤΥޥåԥ󥰤 100% 
.\" ֤⤷פ֤פ֤֤פʤ-- Linus