freebsd-dev/lib/libc/sys/munmap.2

.\" Copyright (c) 1991, 1993
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.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\"	@(#)munmap.2	8.3 (Berkeley) 5/27/94
.\"
.Dd June 22, 2017
.Dt MUNMAP 2
.Os
.Sh NAME
.Nm munmap
.Nd remove a mapping
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/mman.h
.Ft int
.Fn munmap "void *addr" "size_t len"
.Sh DESCRIPTION
The
.Fn munmap
system call
deletes the mappings and guards for the specified address range,
and causes further references to addresses within the range
to generate invalid memory references.
.Sh RETURN VALUES
.Rv -std munmap
.Sh ERRORS
The
.Fn munmap
system call
will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fa addr
argument was not page aligned, the
.Fa len
argument was zero or negative, or
some part of the region being unmapped is outside the
valid address range for a process.
.El
.Sh "SEE ALSO"
.Xr madvise 2 ,
.Xr mincore 2 ,
.Xr mmap 2 ,
.Xr mprotect 2 ,
.Xr msync 2 ,
.Xr getpagesize 3
.Sh HISTORY
The
.Fn munmap
system call first appeared in
.Bx 4.4 .
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" Copyright (c) 1991, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" modification, are permitted provided that the following conditions`
			`.\" are met:`
			`.\" 1. Redistributions of source code must retain the above copyright`
			`.\" notice, this list of conditions and the following disclaimer.`
			`.\" 2. Redistributions in binary form must reproduce the above copyright`
			`.\" notice, this list of conditions and the following disclaimer in the`
			`.\" documentation and/or other materials provided with the distribution.`
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96 2017-02-28 23:42:47 +00:00			`.\" 3. Neither the name of the University nor the names of its contributors`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" may be used to endorse or promote products derived from this software`
			`.\" without specific prior written permission.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
			`.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE`
			`.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`.\" SUCH DAMAGE.`
			`.\"`
Merge from Lite2 onto mainline - - add undelete() and undelete.2 (requires libc minor bump some time) - man page updates 1997-03-11 11:35:56 +00:00			`.\" @(#)munmap.2 8.3 (Berkeley) 5/27/94`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\"`
Implement address space guards. Guard, requested by the MAP_GUARD mmap(2) flag, prevents the reuse of the allocated address space, but does not allow instantiation of the pages in the range. It is useful for more explicit support for usual two-stage reserve then commit allocators, since it prevents accidental instantiation of the mapping, e.g. by mprotect(2). Use guards to reimplement stack grow code. Explicitely track stack grow area with the guard, including the stack guard page. On stack grow, trivial shift of the guard map entry and stack map entry limits makes the stack expansion. Move the code to detect stack grow and call vm_map_growstack(), from vm_fault() into vm_map_lookup(). As result, it is impossible to get random mapping to occur in the stack grow area, or to overlap the stack guard page. Enable stack guard page by default. Reviewed by: alc, markj Man page update reviewed by: alc, bjk, emaste, markj, pho Tested by: pho, Qualys Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D11306 (man pages) 2017-06-24 17:01:11 +00:00			`.Dd June 22, 2017`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Dt MUNMAP 2`
			`.Os`
			`.Sh NAME`
			`.Nm munmap`
			`.Nd remove a mapping`
Introduce ".Lb" macro to libc manpages. More libraries manpages updates following. 2000-04-21 09:42:15 +00:00			`.Sh LIBRARY`
			`.Lb libc`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In sys/mman.h`
Minor mdoc fixes in msync.2 and munmap.2. Add RETURN VALUES and ERRORS sections to mincore. Closes PR# 1493. 1997-01-11 23:33:18 +00:00			`.Ft int`
Convert caddr_t --> void * for sys/mman.h functions. mlock, mmap, mprotect, msync, munlock, and munmap are defined by POSIX as taking void . The const modifier has been added to mlock, munlock, and mprotect as the standard dictates. minherit comes from OpenBSD and has been updated to conform with their recent change to void . madvise and mincore are not defined by POSIX, but their arguments have been modified to be consistent with the POSIX-defined functions. mincore takes a const pointer, but madvise does not due to the MADV_FREE case. Discussed with: bde 1997-12-31 01:22:01 +00:00			`.Fn munmap "void *addr" "size_t len"`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh DESCRIPTION`
			`The`
			`.Fn munmap`
			`system call`
Implement address space guards. Guard, requested by the MAP_GUARD mmap(2) flag, prevents the reuse of the allocated address space, but does not allow instantiation of the pages in the range. It is useful for more explicit support for usual two-stage reserve then commit allocators, since it prevents accidental instantiation of the mapping, e.g. by mprotect(2). Use guards to reimplement stack grow code. Explicitely track stack grow area with the guard, including the stack guard page. On stack grow, trivial shift of the guard map entry and stack map entry limits makes the stack expansion. Move the code to detect stack grow and call vm_map_growstack(), from vm_fault() into vm_map_lookup(). As result, it is impossible to get random mapping to occur in the stack grow area, or to overlap the stack guard page. Enable stack guard page by default. Reviewed by: alc, markj Man page update reviewed by: alc, bjk, emaste, markj, pho Tested by: pho, Qualys Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D11306 (man pages) 2017-06-24 17:01:11 +00:00			`deletes the mappings and guards for the specified address range,`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`and causes further references to addresses within the range`
			`to generate invalid memory references.`
			`.Sh RETURN VALUES`
Use the ``.Rv -std'' mdoc(7) macro in appropriate cases. Reviewed by: ru 2001-08-09 13:32:13 +00:00			`.Rv -std munmap`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh ERRORS`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`The`
			`.Fn munmap`
			`system call`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`will fail if:`
			`.Bl -tag -width Er`
			`.It Bq Er EINVAL`
			`The`
			`.Fa addr`
mdoc(7) police: "The .Fa argument.". 2002-12-19 09:40:28 +00:00			`argument was not page aligned, the`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Fa len`
Document EINVAL for len == 0. 2003-11-10 08:02:05 +00:00			`argument was zero or negative, or`
Merge from Lite2 onto mainline - - add undelete() and undelete.2 (requires libc minor bump some time) - man page updates 1997-03-11 11:35:56 +00:00			`some part of the region being unmapped is outside the`
			`valid address range for a process.`
Prepare for mdoc(7)NG. 2000-12-29 14:08:20 +00:00			`.El`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh "SEE ALSO"`
			`.Xr madvise 2 ,`
Correct a bunch of man page cross references and generally try and silence "manck". ncurses, rpc, and some of the gnu stuff are still a big mess, however. 1996-02-11 22:38:05 +00:00			`.Xr mincore 2 ,`
We are munmap(2), so there's no need to list ourselves in the SEE ALSO section; instead, list our partner in crime, mmap(2). PR: 33153 Submitted by: Faried Nawaz <fn@hungry.org> 2002-01-07 06:12:25 +00:00			`.Xr mmap 2 ,`
Minor mdoc fixes in msync.2 and munmap.2. Add RETURN VALUES and ERRORS sections to mincore. Closes PR# 1493. 1997-01-11 23:33:18 +00:00			`.Xr mprotect 2 ,`
Sort cross references. 1997-01-20 23:23:22 +00:00			`.Xr msync 2 ,`
Correct a bunch of man page cross references and generally try and silence "manck". ncurses, rpc, and some of the gnu stuff are still a big mess, however. 1996-02-11 22:38:05 +00:00			`.Xr getpagesize 3`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh HISTORY`
			`The`
			`.Fn munmap`
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe. 2002-12-18 09:22:32 +00:00			`system call first appeared in`
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages. 1996-08-22 23:31:07 +00:00			`.Bx 4.4 .`