84d9c625bf
- Fix for possible unset uid/gid in toproto
- Fix for default mtree style
- Update libelf
- Importing libexecinfo
- Resynchronize GCC, mpc, gmp, mpfr
- build.sh: Replace params with show-params.
This has been done as the make target has been renamed in the same
way, while a new target named params has been added. This new
target generates a file containing all the parameters, instead of
printing it on the console.
- Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
get getservbyport() out of the inner loop
Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
92 lines
3 KiB
Groff
92 lines
3 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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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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.\" from: @(#)memcmp.3 8.1 (Berkeley) 6/4/93
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.\" $NetBSD: memcmp.3,v 1.11 2013/06/24 04:21:20 riastradh Exp $
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.\"
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.Dd June 23, 2013
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.Dt MEMCMP 3
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.Os
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.Sh NAME
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.Nm memcmp
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.Nd compare byte string
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In string.h
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.Ft int
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.Fn memcmp "const void *b1" "const void *b2" "size_t len"
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.Sh DESCRIPTION
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The
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.Fn memcmp
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function
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compares byte string
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.Fa b1
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against byte string
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.Fa b2 .
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Both strings are assumed to be
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.Fa len
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bytes long.
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.Sh RETURN VALUES
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The
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.Fn memcmp
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function
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returns zero if the two strings are identical,
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otherwise returns the difference between the first two differing bytes
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(treated as unsigned char values, so that
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.Sq Li \e200
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is greater than
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.Sq Li \&\e0 ,
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for example).
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Zero-length strings are always identical.
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.Pp
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Do not use
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.Fn memcmp
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to compare cryptographic secrets, because the time it takes varies
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depending on how many bytes are the same, and thus leaks information
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about the two strings by a timing side channel.
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To compare secrets, hashes, message authentication codes, etc., use
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.Xr consttime_memequal 3
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instead.
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.Sh SEE ALSO
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.Xr bcmp 3 ,
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.Xr consttime_memequal 3 ,
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.Xr strcasecmp 3 ,
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.Xr strcmp 3 ,
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.Xr strcoll 3 ,
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.Xr strxfrm 3
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.Sh STANDARDS
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The
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.Fn memcmp
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function
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conforms to
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.St -ansiC .
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