IABSD.fr/src/lib/libc/stdlib/rand.c

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• Author : tb
  Date : 2017-11-28 06:55:49
  Hash : e34cb67c
  Message : GNU ld has prefixed the contents of .gnu.warning.SYMBOL sections with "warning: " since 2003, so the messages themselves need not contain the prefix anymore. From Scott Cheloha ok jca, deraadt

• lib/libc/stdlib/rand.c

• /*	$OpenBSD: rand.c,v 1.18 2017/11/28 06:55:49 tb Exp $ */
  /*-
   * Copyright (c) 1990 The Regents of the University of California.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/types.h>
  #include <stdlib.h>
  
  static int rand_deterministic;
  static u_int next = 1;
  
  int
  rand_r(u_int *seed)
  {
  	*seed = *seed * 1103515245 + 12345;
  	return (*seed & RAND_MAX);
  }
  DEF_WEAK(rand_r);
  
  #if defined(APIWARN)
  __warn_references(rand_r,
      "rand_r() is not random, it is deterministic.");
  #endif
  
  int
  rand(void)
  {
  	if (rand_deterministic == 0)
  		return (arc4random() & RAND_MAX);
  	return (rand_r(&next));
  }
  
  #if defined(APIWARN)
  __warn_references(rand,
      "rand() may return deterministic values, is that what you want?");
  #endif
  
  void
  srand(u_int seed)
  {
  	rand_deterministic = 0;
  }
  
  void
  srand_deterministic(u_int seed)
  {
  	rand_deterministic = 1;
  	next = seed;
  }