rand.c revision 1.15 
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/types.h>
31#include <stdlib.h>
32
33static int rand_deterministic;
34static u_int next = 1;
35
36int
37rand_r(u_int *seed)
38{
39	*seed = *seed * 1103515245 + 12345;
40	return (*seed % ((u_int)RAND_MAX + 1));
41}
42DEF_WEAK(rand_r);
43
44#if defined(APIWARN)
45__warn_references(rand_r,
46    "warning: rand_r() is not random, it is deterministic.");
47#endif
48
49int
50rand(void)
51{
52	if (rand_deterministic == 0)
53		return (arc4random() % ((u_int)RAND_MAX + 1));
54	return (rand_r(&next));
55}
56
57#if defined(APIWARN)
58__warn_references(rand,
59    "warning: rand() may return deterministic values, is that what you want?");
60#endif
61
62void
63srand(u_int seed)
64{
65	rand_deterministic = 0;
66}
67
68void
69srand_deterministic(u_int seed)
70{
71	rand_deterministic = 1;
72	next = seed;
73}
74