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.\" $DragonFly: src/lib/libc/sys/mprotect.2,v 1.4 2004/07/15 04:50:49 hmp Exp $ 35.\" 36.Dd June 9, 1993 37.Dt MPROTECT 2 38.Os 39.Sh NAME 40.Nm mprotect 41.Nd control the protection of pages 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In sys/types.h 46.In sys/mman.h 47.Ft int 48.Fn mprotect "const void *addr" "size_t len" "int prot" 49.Sh DESCRIPTION 50The 51.Fn mprotect 52system call 53changes the specified pages to have protection 54.Fa prot . 55Not all implementations will guarantee protection on a page basis; 56the granularity of protection changes may be as large as an entire region. 57A region is the virtual address space defined by the start 58and end addresses of a 59.Vt "struct vm_map_entry" . 60.Pp 61Currently these protection bits are known, 62which can be combined, OR'd together: 63.Bl -tag -width "PROT_WRITE" -offset indent 64.It Dv PROT_NONE 65No permissions at all. 66.It Dv PROT_READ 67The pages can be read. 68.It Dv PROT_WRITE 69The pages can be written. 70.It Dv PROT_EXEC 71The pages can be executed. 72.El 73.Sh RETURN VALUES 74.Rv -std mprotect 75.Sh ERRORS 76The 77.Fn mprotect 78function will fail if: 79.Bl -tag -width Er 80.It Bq Er EINVAL 81The virtual address range specified by the 82.Fa addr 83and 84.Fa len 85arguments is not valid. 86.It Bq Er EACCES 87The calling process was not allowed to change 88the protection to the value specified by 89the 90.Fa prot 91argument. 92.El 93.Sh SEE ALSO 94.Xr madvise 2 , 95.Xr mincore 2 , 96.Xr msync 2 , 97.Xr munmap 2 98.Sh HISTORY 99The 100.Fn mprotect 101function first appeared in 102.Bx 4.4 . 103