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/* $OpenBSD: rand.c,v 1.17 2016/10/22 19:19:34 tb Exp $ */ |
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/*- |
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* Copyright (c) 1990 The Regents of the University of California. |
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* 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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#include <sys/types.h> |
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#include <stdlib.h> |
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static int rand_deterministic; |
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static u_int next = 1; |
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int |
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rand_r(u_int *seed) |
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{ |
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*seed = *seed * 1103515245 + 12345; |
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return (*seed & RAND_MAX); |
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} |
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DEF_WEAK(rand_r); |
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#if defined(APIWARN) |
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__warn_references(rand_r, |
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"warning: rand_r() is not random, it is deterministic."); |
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#endif |
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int |
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rand(void) |
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{ |
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✓✓ |
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if (rand_deterministic == 0) |
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return (arc4random() & RAND_MAX); |
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return (rand_r(&next)); |
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} |
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#if defined(APIWARN) |
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__warn_references(rand, |
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"warning: rand() may return deterministic values, is that what you want?"); |
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#endif |
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void |
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srand(u_int seed) |
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{ |
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rand_deterministic = 0; |
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} |
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void |
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srand_deterministic(u_int seed) |
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{ |
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rand_deterministic = 1; |
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next = seed; |
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} |