source: trunk/third-party/evutil_rand.c @ 12568

Last change on this file since 12568 was 12568, checked in by livings124, 11 years ago

add a temporary custom version of evutil_rand.c

File size: 4.0 KB
Line 
1/*
2 * Copyright (c) 2007-2010 Niels Provos and Nick Mathewson
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. The name of the author may not be used to endorse or promote products
13 *    derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27/* This file has our secure PRNG code.  On platforms that have arc4random(),
28 * we just use that.  Otherwise, we include arc4random.c as a bunch of static
29 * functions, and wrap it lightly.  We don't expose the arc4random*() APIs
30 * because A) they aren't in our namespace, and B) it's not nice to name your
31 * APIs after their implementations.  We keep them in a separate file
32 * so that other people can rip it out and use it for whatever.
33 */
34
35#include "event2/event-config.h"
36
37#include <limits.h>
38
39#include "util-internal.h"
40#include "evthread-internal.h"
41
42#ifdef _EVENT_HAVE_ARC4RANDOM
43#include <stdlib.h>
44#include <string.h>
45int
46evutil_secure_rng_init(void)
47{
48        /* call arc4random() now to force it to self-initialize */
49        (void) arc4random();
50        return 0;
51}
52int
53evutil_secure_rng_global_setup_locks_(const int enable_locks)
54{
55        return 0;
56}
57
58static void
59ev_arc4random_buf(void *buf, size_t n)
60{
61#ifdef _EVENT_HAVE_ARC4RANDOM_BUF
62    arc4random_buf(buf, n);
63#else
64        unsigned char *b = buf;
65        /* Make sure that we start out with b at a 4-byte alignment; plenty
66         * of CPUs care about this for 32-bit access. */
67        if (n >= 4 && ((ev_uintptr_t)b) & 3) {
68                ev_uint32_t u = arc4random();
69                int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
70                memcpy(b, &u, n_bytes);
71                b += n_bytes;
72                n -= n_bytes;
73        }
74        while (n >= 4) {
75                *(ev_uint32_t*)b = arc4random();
76                b += 4;
77                n -= 4;
78        }
79        if (n) {
80                ev_uint32_t u = arc4random();
81                memcpy(b, &u, n);
82        }
83#endif
84}
85
86#else /* !_EVENT_HAVE_ARC4RANDOM { */
87
88#ifdef _EVENT_ssize_t
89#define ssize_t _EVENT_SSIZE_t
90#endif
91#define ARC4RANDOM_EXPORT static
92#define _ARC4_LOCK() EVLOCK_LOCK(arc4rand_lock, 0)
93#define _ARC4_UNLOCK() EVLOCK_UNLOCK(arc4rand_lock, 0)
94#ifndef _EVENT_DISABLE_THREAD_SUPPORT
95static void *arc4rand_lock;
96#endif
97
98#define ARC4RANDOM_UINT32 ev_uint32_t
99#define ARC4RANDOM_NOSTIR
100#define ARC4RANDOM_NORANDOM
101#define ARC4RANDOM_NOUNIFORM
102
103#include "./arc4random.c"
104
105#ifndef _EVENT_DISABLE_THREAD_SUPPORT
106int
107evutil_secure_rng_global_setup_locks_(const int enable_locks)
108{
109        EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
110        return 0;
111}
112#endif
113
114int
115evutil_secure_rng_init(void)
116{
117        int val;
118
119        _ARC4_LOCK();
120        if (!arc4_seeded_ok)
121                arc4_stir();
122        val = arc4_seeded_ok ? 0 : -1;
123        _ARC4_UNLOCK();
124        return val;
125}
126
127static void
128ev_arc4random_buf(void *buf, size_t n)
129{
130    arc4random_buf(buf, n);
131}
132
133#endif /* } !_EVENT_HAVE_ARC4RANDOM */
134
135void
136evutil_secure_rng_get_bytes(void *buf, size_t n)
137{
138        ev_arc4random_buf(buf, n);
139}
140
141void
142evutil_secure_rng_add_bytes(const char *buf, size_t n)
143{
144        arc4random_addrandom((unsigned char*)buf,
145            n>(size_t)INT_MAX ? INT_MAX : (int)n);
146}
147
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