1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. 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 * Posix rand_r function added May 1999 by Wes Peters <wes@softweyr.com>.
30 */
31
32#if defined(LIBC_SCCS) && !defined(lint)
33static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93";
34#endif /* LIBC_SCCS and not lint */
35#include <sys/cdefs.h>
| 1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. 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 * Posix rand_r function added May 1999 by Wes Peters <wes@softweyr.com>.
30 */
31
32#if defined(LIBC_SCCS) && !defined(lint)
33static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93";
34#endif /* LIBC_SCCS and not lint */
35#include <sys/cdefs.h>
|
36__FBSDID("$FreeBSD: head/lib/libc/stdlib/rand.c 252608 2013-07-03 21:21:54Z ache $");
| 36__FBSDID("$FreeBSD: head/lib/libc/stdlib/rand.c 252648 2013-07-03 23:27:04Z ache $");
|
37
38#include "namespace.h"
39#include <sys/param.h>
40#include <sys/sysctl.h>
41#include <sys/types.h>
42#include <stdlib.h>
43#include "un-namespace.h"
44
45#ifdef TEST
46#include <stdio.h>
47#endif /* TEST */
48
49static int
50do_rand(unsigned long *ctx)
51{
52#ifdef USE_WEAK_SEEDING
53/*
54 * Historic implementation compatibility.
55 * The random sequences do not vary much with the seed,
56 * even with overflowing.
57 */
58 return ((*ctx = *ctx * 1103515245 + 12345) % ((u_long)RAND_MAX + 1));
59#else /* !USE_WEAK_SEEDING */
60/*
61 * Compute x = (7^5 * x) mod (2^31 - 1)
62 * without overflowing 31 bits:
63 * (2^31 - 1) = 127773 * (7^5) + 2836
64 * From "Random number generators: good ones are hard to find",
65 * Park and Miller, Communications of the ACM, vol. 31, no. 10,
66 * October 1988, p. 1195.
67 */
68 long hi, lo, x;
69
70 /* Must be in [1, 0x7ffffffe] range at this point. */
71 hi = *ctx / 127773;
72 lo = *ctx % 127773;
73 x = 16807 * lo - 2836 * hi;
74 if (x < 0)
75 x += 0x7fffffff;
76 *ctx = x;
77 /* Transform to [0, 0x7ffffffd] range. */
78 return (x - 1);
79#endif /* !USE_WEAK_SEEDING */
80}
81
82
83int
84rand_r(unsigned int *ctx)
85{
86 u_long val = (u_long) *ctx;
87#ifndef USE_WEAK_SEEDING
88 /* Transform to [1, 0x7ffffffe] range. */
89 val = (val % 0x7ffffffe) + 1;
90#endif
91 int r = do_rand(&val);
92
| 37
38#include "namespace.h"
39#include <sys/param.h>
40#include <sys/sysctl.h>
41#include <sys/types.h>
42#include <stdlib.h>
43#include "un-namespace.h"
44
45#ifdef TEST
46#include <stdio.h>
47#endif /* TEST */
48
49static int
50do_rand(unsigned long *ctx)
51{
52#ifdef USE_WEAK_SEEDING
53/*
54 * Historic implementation compatibility.
55 * The random sequences do not vary much with the seed,
56 * even with overflowing.
57 */
58 return ((*ctx = *ctx * 1103515245 + 12345) % ((u_long)RAND_MAX + 1));
59#else /* !USE_WEAK_SEEDING */
60/*
61 * Compute x = (7^5 * x) mod (2^31 - 1)
62 * without overflowing 31 bits:
63 * (2^31 - 1) = 127773 * (7^5) + 2836
64 * From "Random number generators: good ones are hard to find",
65 * Park and Miller, Communications of the ACM, vol. 31, no. 10,
66 * October 1988, p. 1195.
67 */
68 long hi, lo, x;
69
70 /* Must be in [1, 0x7ffffffe] range at this point. */
71 hi = *ctx / 127773;
72 lo = *ctx % 127773;
73 x = 16807 * lo - 2836 * hi;
74 if (x < 0)
75 x += 0x7fffffff;
76 *ctx = x;
77 /* Transform to [0, 0x7ffffffd] range. */
78 return (x - 1);
79#endif /* !USE_WEAK_SEEDING */
80}
81
82
83int
84rand_r(unsigned int *ctx)
85{
86 u_long val = (u_long) *ctx;
87#ifndef USE_WEAK_SEEDING
88 /* Transform to [1, 0x7ffffffe] range. */
89 val = (val % 0x7ffffffe) + 1;
90#endif
91 int r = do_rand(&val);
92
|
93 *ctx = (unsigned int) val;
| 93#ifdef USE_WEAK_SEEDING
94 *ctx = (unsigned int)val;
95#else
96 *ctx = (unsigned int)(val - 1);
97#endif
|
94 return (r);
95}
96
97
98static u_long next = 1;
99
100int
101rand()
102{
103 return (do_rand(&next));
104}
105
106void
107srand(seed)
108u_int seed;
109{
110 next = seed;
111#ifndef USE_WEAK_SEEDING
112 /* Transform to [1, 0x7ffffffe] range. */
113 next = (next % 0x7ffffffe) + 1;
114#endif
115}
116
117
118/*
119 * sranddev:
120 *
121 * Many programs choose the seed value in a totally predictable manner.
122 * This often causes problems. We seed the generator using pseudo-random
123 * data from the kernel.
124 */
125void
126sranddev()
127{
128 int mib[2];
129 size_t len;
130
131 len = sizeof(next);
132
133 mib[0] = CTL_KERN;
134 mib[1] = KERN_ARND;
135 sysctl(mib, 2, (void *)&next, &len, NULL, 0);
136#ifndef USE_WEAK_SEEDING
137 /* Transform to [1, 0x7ffffffe] range. */
138 next = (next % 0x7ffffffe) + 1;
139#endif
140}
141
142
143#ifdef TEST
144
145main()
146{
147 int i;
148 unsigned myseed;
149
150 printf("seeding rand with 0x19610910: \n");
151 srand(0x19610910);
152
153 printf("generating three pseudo-random numbers:\n");
154 for (i = 0; i < 3; i++)
155 {
156 printf("next random number = %d\n", rand());
157 }
158
159 printf("generating the same sequence with rand_r:\n");
160 myseed = 0x19610910;
161 for (i = 0; i < 3; i++)
162 {
163 printf("next random number = %d\n", rand_r(&myseed));
164 }
165
166 return 0;
167}
168
169#endif /* TEST */
170
| 98 return (r);
99}
100
101
102static u_long next = 1;
103
104int
105rand()
106{
107 return (do_rand(&next));
108}
109
110void
111srand(seed)
112u_int seed;
113{
114 next = seed;
115#ifndef USE_WEAK_SEEDING
116 /* Transform to [1, 0x7ffffffe] range. */
117 next = (next % 0x7ffffffe) + 1;
118#endif
119}
120
121
122/*
123 * sranddev:
124 *
125 * Many programs choose the seed value in a totally predictable manner.
126 * This often causes problems. We seed the generator using pseudo-random
127 * data from the kernel.
128 */
129void
130sranddev()
131{
132 int mib[2];
133 size_t len;
134
135 len = sizeof(next);
136
137 mib[0] = CTL_KERN;
138 mib[1] = KERN_ARND;
139 sysctl(mib, 2, (void *)&next, &len, NULL, 0);
140#ifndef USE_WEAK_SEEDING
141 /* Transform to [1, 0x7ffffffe] range. */
142 next = (next % 0x7ffffffe) + 1;
143#endif
144}
145
146
147#ifdef TEST
148
149main()
150{
151 int i;
152 unsigned myseed;
153
154 printf("seeding rand with 0x19610910: \n");
155 srand(0x19610910);
156
157 printf("generating three pseudo-random numbers:\n");
158 for (i = 0; i < 3; i++)
159 {
160 printf("next random number = %d\n", rand());
161 }
162
163 printf("generating the same sequence with rand_r:\n");
164 myseed = 0x19610910;
165 for (i = 0; i < 3; i++)
166 {
167 printf("next random number = %d\n", rand_r(&myseed));
168 }
169
170 return 0;
171}
172
173#endif /* TEST */
174
|