107 lines
3.3 KiB
Groff
107 lines
3.3 KiB
Groff
.\" $NetBSD: mprotect.2,v 1.26 2017/05/14 12:30:37 wiz Exp $
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.\"
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.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)mprotect.2 8.1 (Berkeley) 6/9/93
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.\"
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.Dd April 27, 2017
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.Dt MPROTECT 2
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.Os
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.Sh NAME
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.Nm mprotect
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.Nd control the protection of pages
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/mman.h
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.Ft int
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.Fn mprotect "void *addr" "size_t len" "int prot"
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.Sh DESCRIPTION
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The
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.Fn mprotect
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system call
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changes the specified pages to have protection
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.Fa prot .
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Not all implementations will guarantee protection on a page basis;
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the granularity of protection changes may be as large as an entire region.
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.Pp
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The protections (region accessibility) are specified in the
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.Fa prot
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argument by
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.Tn OR Ns 'ing
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the following values:
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.Pp
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.Bl -tag -width MAP_FIXEDX -offset indent
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.It Dv PROT_EXEC
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Pages may be executed.
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.It Dv PROT_READ
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Pages may be read.
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.It Dv PROT_WRITE
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Pages may be written.
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.It Dv PROT_NONE
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Placeholder when requesting no access permission.
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.El
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.Sh RETURN VALUES
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Upon successful completion,
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a value of 0 is returned.
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Otherwise, a value of \-1 is returned and
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EACCES
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A memory protection violation occurred.
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.Pp
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The
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.Dv PROT_EXEC
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flag was attempted on pages which belong to a file system mounted with the
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.Dv NOEXEC
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flag.
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.Pp
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The new protection is less restrictive than the protection originally
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set with
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.Xr mmap 2 .
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.Pp
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PAX mprotect restrictions prohibit the requested protection.
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.It Bq Er EINVAL
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An invalid memory range, or invalid parameters were provided.
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.It Bq Er ENOMEM
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A resource shortage occurred while internally calling
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.Xr uvm_map_protect 9 .
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.El
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.Sh SEE ALSO
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.Xr madvise 2 ,
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.Xr mincore 2 ,
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.Xr msync 2 ,
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.Xr munmap 2
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.Sh HISTORY
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The
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.Fn mprotect
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function first appeared in
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.Bx 4.4 .
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