[apple/xnu.git] / bsd / man / man2 / mprotect.2

.\"
.\" Copyright (c) 2008 Apple Inc.  All rights reserved.
.\"
.\" @APPLE_LICENSE_HEADER_START@
.\" 
.\" This file contains Original Code and/or Modifications of Original Code
.\" as defined in and that are subject to the Apple Public Source License
.\" Version 2.0 (the 'License'). You may not use this file except in
.\" compliance with the License. Please obtain a copy of the License at
.\" http://www.opensource.apple.com/apsl/ and read it before using this
.\" file.
.\" 
.\" The Original Code and all software distributed under the License are
.\" distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
.\" FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
.\" Please see the License for the specific language governing rights and
.\" limitations under the License.
.\" 
.\" @APPLE_LICENSE_HEADER_END@
.\"
.\"
.\"	$NetBSD: mprotect.2,v 1.6 1995/10/12 15:41:08 jtc Exp $
.\"
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. 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.
.\"
.\" 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.
.\"
.\"	@(#)mprotect.2	8.1 (Berkeley) 6/9/93
.\" $FreeBSD: src/lib/libc/sys/mprotect.2,v 1.18 2007/01/09 00:28:15 imp Exp $
.\"
.Dd October 16, 2008
.Dt MPROTECT 2
.Os
.Sh NAME
.Nm mprotect
.Nd control the protection of pages
.Sh SYNOPSIS
.Fd #include <sys/mman.h>
.Ft int
.Fo mprotect
.Fa "void *addr"
.Fa "size_t len"
.Fa "int prot"
.Fc
.Sh DESCRIPTION
The
.Fn mprotect
system call
changes the specified pages to have protection
.Fa prot .
Not all implementations will guarantee protection on a page basis but Mac OS X's
current implementation does.
.Pp
When a program violates the protections of a page, it gets a SIGBUS or SIGSEGV signal. 
.Pp
Currently
.Fa prot
can be one or more of the following:
.Pp
.Bl -tag -width ".Dv PROT_WRITE" -compact
.It Dv PROT_NONE
No permissions at all.
.It Dv PROT_READ
The pages can be read.
.It Dv PROT_WRITE
The pages can be written.
.It Dv PROT_EXEC
The pages can be executed.
.El
.Sh RETURN VALUES
Upon successful completion,
a value of 0 is returned.
Otherwise, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn mprotect
will fail if:
.Bl -tag -width Er
.\" ===========
.It Bq Er EACCES
The requested protection conflicts with
the access permissions of the process
on the specified address range.
.\" ===========
.\" .It Bq Er EAGAIN
.\" Insufficient memory resources exist to allow locking a private page
.\" under PROT_WRITE.
.\" ===========
.It Bq Er EINVAL
.Fa addr
is not a multiple of the page size (i.e.
.Fa addr
is not page-aligned).
.\" ===========
.\" .It Bq Er ENOMEM
.\" The specified address range is outside of the address range
.\" of the process or includes an unmapped page.
.\" ===========
.It Bq Er ENOTSUP
The combination of accesses requested in
.Fa prot
is not supported.
.El
.Sh LEGACY SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/mman.h>
.Pp
The include file
.In sys/types.h
is necessary.
.Pp
.Ft int
.br
.Fo mprotect
.Fa "caddr_t addr"
.Fa "size_t len"
.Fa "int prot"
.Fc ;
.Pp
The type of
.Fa addr
has changed.
.Sh SEE ALSO
.Xr madvise 2 , 
.Xr mincore 2 , 
.Xr msync 2 ,
.Xr munmap 2 ,
.Xr compat 5
.Sh HISTORY
The
.Fn mprotect
function first appeared in 4.4BSD.
Commit	Line	Data
b0d623f7 A	1	.\"
	2	.\" Copyright (c) 2008 Apple Inc. All rights reserved.
	3	.\"
	4	.\" @APPLE_LICENSE_HEADER_START@
	5	.\"
	6	.\" This file contains Original Code and/or Modifications of Original Code
	7	.\" as defined in and that are subject to the Apple Public Source License
	8	.\" Version 2.0 (the 'License'). You may not use this file except in
	9	.\" compliance with the License. Please obtain a copy of the License at
	10	.\" http://www.opensource.apple.com/apsl/ and read it before using this
	11	.\" file.
	12	.\"
	13	.\" The Original Code and all software distributed under the License are
	14	.\" distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	15	.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	16	.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	17	.\" FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	.\" Please see the License for the specific language governing rights and
	19	.\" limitations under the License.
	20	.\"
	21	.\" @APPLE_LICENSE_HEADER_END@
	22	.\"
	23	.\"
9bccf70c A	24	.\" $NetBSD: mprotect.2,v 1.6 1995/10/12 15:41:08 jtc Exp $
	25	.\"
	26	.\" Copyright (c) 1991, 1993
	27	.\" The Regents of the University of California. All rights reserved.
	28	.\"
	29	.\" Redistribution and use in source and binary forms, with or without
	30	.\" modification, are permitted provided that the following conditions
	31	.\" are met:
	32	.\" 1. Redistributions of source code must retain the above copyright
	33	.\" notice, this list of conditions and the following disclaimer.
	34	.\" 2. Redistributions in binary form must reproduce the above copyright
	35	.\" notice, this list of conditions and the following disclaimer in the
	36	.\" documentation and/or other materials provided with the distribution.
	37	.\" 3. All advertising materials mentioning features or use of this software
	38	.\" must display the following acknowledgement:
	39	.\" This product includes software developed by the University of
	40	.\" California, Berkeley and its contributors.
	41	.\" 4. Neither the name of the University nor the names of its contributors
	42	.\" may be used to endorse or promote products derived from this software
	43	.\" without specific prior written permission.
	44	.\"
	45	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	46	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	47	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	48	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	49	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	50	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	51	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	52	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	53	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	54	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	55	.\" SUCH DAMAGE.
	56	.\"
	57	.\" @(#)mprotect.2 8.1 (Berkeley) 6/9/93
b0d623f7	58	.\" $FreeBSD: src/lib/libc/sys/mprotect.2,v 1.18 2007/01/09 00:28:15 imp Exp $
9bccf70c	59	.\"
b0d623f7	60	.Dd October 16, 2008
9bccf70c A	61	.Dt MPROTECT 2
	62	.Os
	63	.Sh NAME
	64	.Nm mprotect
	65	.Nd control the protection of pages
	66	.Sh SYNOPSIS
9bccf70c A	67	.Fd #include <sys/mman.h>
9bccf70c A	68	.Ft int
2d21ac55 A	69	.Fo mprotect
	70	.Fa "void *addr"
	71	.Fa "size_t len"
	72	.Fa "int prot"
	73	.Fc
9bccf70c A	74	.Sh DESCRIPTION
	75	The
	76	.Fn mprotect
	77	system call
	78	changes the specified pages to have protection
	79	.Fa prot .
b0d623f7 A	80	Not all implementations will guarantee protection on a page basis but Mac OS X's
	81	current implementation does.
	82	.Pp
	83	When a program violates the protections of a page, it gets a SIGBUS or SIGSEGV signal.
	84	.Pp
	85	Currently
	86	.Fa prot
	87	can be one or more of the following:
	88	.Pp
	89	.Bl -tag -width ".Dv PROT_WRITE" -compact
	90	.It Dv PROT_NONE
	91	No permissions at all.
	92	.It Dv PROT_READ
	93	The pages can be read.
	94	.It Dv PROT_WRITE
	95	The pages can be written.
	96	.It Dv PROT_EXEC
	97	The pages can be executed.
	98	.El
9bccf70c A	99	.Sh RETURN VALUES
	100	Upon successful completion,
	101	a value of 0 is returned.
	102	Otherwise, a value of -1 is returned and
	103	.Va errno
	104	is set to indicate the error.
2d21ac55 A	105	.Sh ERRORS
	106	.Fn mprotect
	107	will fail if:
	108	.Bl -tag -width Er
	109	.\" ===========
	110	.It Bq Er EACCES
	111	The requested protection conflicts with
	112	the access permissions of the process
	113	on the specified address range.
	114	.\" ===========
	115	.\" .It Bq Er EAGAIN
	116	.\" Insufficient memory resources exist to allow locking a private page
	117	.\" under PROT_WRITE.
	118	.\" ===========
	119	.It Bq Er EINVAL
	120	.Fa addr
b0d623f7 A	121	is not a multiple of the page size (i.e.
	122	.Fa addr
	123	is not page-aligned).
2d21ac55 A	124	.\" ===========
	125	.\" .It Bq Er ENOMEM
	126	.\" The specified address range is outside of the address range
	127	.\" of the process or includes an unmapped page.
	128	.\" ===========
	129	.It Bq Er ENOTSUP
	130	The combination of accesses requested in
	131	.Fa prot
	132	is not supported.
	133	.El
	134	.Sh LEGACY SYNOPSIS
	135	.Fd #include <sys/types.h>
	136	.Fd #include <sys/mman.h>
	137	.Pp
	138	The include file
	139	.In sys/types.h
	140	is necessary.
	141	.Pp
	142	.Ft int
	143	.br
	144	.Fo mprotect
	145	.Fa "caddr_t addr"
	146	.Fa "size_t len"
	147	.Fa "int prot"
	148	.Fc ;
	149	.Pp
	150	The type of
	151	.Fa addr
	152	has changed.
9bccf70c A	153	.Sh SEE ALSO
	154	.Xr madvise 2 ,
	155	.Xr mincore 2 ,
	156	.Xr msync 2 ,
2d21ac55 A	157	.Xr munmap 2 ,
2d21ac55 A	158	.Xr compat 5
9bccf70c A	159	.Sh HISTORY
	160	The
	161	.Fn mprotect
	162	function first appeared in 4.4BSD.