1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)mprotect.2 8.1 (Berkeley) 6/9/93 33.\" $FreeBSD: src/lib/libc/sys/mprotect.2,v 1.9.2.5 2002/12/23 20:47:17 trhodes Exp $ 34.\" 35.Dd January 31, 2010 36.Dt MPROTECT 2 37.Os 38.Sh NAME 39.Nm mprotect 40.Nd control the protection of pages 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In sys/types.h 45.In sys/mman.h 46.Ft int 47.Fn mprotect "void *addr" "size_t len" "int prot" 48.Sh DESCRIPTION 49The 50.Fn mprotect 51system call 52changes the specified pages to have protection 53.Fa prot . 54Not all implementations will guarantee protection on a page basis; 55the granularity of protection changes may be as large as an entire region. 56A region is the virtual address space defined by the start 57and end addresses of a 58.Vt "struct vm_map_entry" . 59.Pp 60Currently these protection bits are known, 61which can be combined, OR'd together: 62.Bl -tag -width "PROT_WRITE" -offset indent 63.It Dv PROT_NONE 64No permissions at all. 65.It Dv PROT_READ 66The pages can be read. 67.It Dv PROT_WRITE 68The pages can be written. 69.It Dv PROT_EXEC 70The pages can be executed. 71.El 72.Sh RETURN VALUES 73.Rv -std mprotect 74.Sh ERRORS 75The 76.Fn mprotect 77function will fail if: 78.Bl -tag -width Er 79.It Bq Er EINVAL 80The virtual address range specified by the 81.Fa addr 82and 83.Fa len 84arguments is not valid. 85.It Bq Er EACCES 86The calling process was not allowed to change 87the protection to the value specified by 88the 89.Fa prot 90argument. 91.El 92.Sh SEE ALSO 93.Xr madvise 2 , 94.Xr mincore 2 , 95.Xr msync 2 , 96.Xr munmap 2 97.Sh HISTORY 98The 99.Fn mprotect 100function first appeared in 101.Bx 4.4 . 102