1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/*
* Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_IO_H
#include <io.h>
#endif
#if HAVE_CRYPTGENRANDOM
#include <windows.h>
#include <wincrypt.h>
#endif
#include <fcntl.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include "avassert.h"
#include "internal.h"
#include "intreadwrite.h"
#include "timer.h"
#include "random_seed.h"
#include "sha.h"
#ifndef TEST
#define TEST 0
#endif
static int read_random(uint32_t *dst, const char *file)
{
#if HAVE_UNISTD_H
int fd = avpriv_open(file, O_RDONLY);
int err = -1;
if (fd == -1)
return -1;
err = read(fd, dst, sizeof(*dst));
close(fd);
return err;
#else
return -1;
#endif
}
static uint32_t get_generic_seed(void)
{
uint64_t tmp[120/8];
struct AVSHA *sha = (void*)tmp;
clock_t last_t = 0;
clock_t last_td = 0;
static uint64_t i = 0;
static uint32_t buffer[512] = { 0 };
unsigned char digest[20];
uint64_t last_i = i;
av_assert0(sizeof(tmp) >= av_sha_size);
if(TEST){
memset(buffer, 0, sizeof(buffer));
last_i = i = 0;
}else{
#ifdef AV_READ_TIME
buffer[13] ^= AV_READ_TIME();
buffer[41] ^= AV_READ_TIME()>>32;
#endif
}
for (;;) {
clock_t t = clock();
if (last_t + 2*last_td + 1 >= t) {
last_td = t - last_t;
buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U);
} else {
last_td = t - last_t;
buffer[++i & 511] += last_td % 3294638521U;
if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8)
break;
}
last_t = t;
}
if(TEST) {
buffer[0] = buffer[1] = 0;
} else {
#ifdef AV_READ_TIME
buffer[111] += AV_READ_TIME();
#endif
}
av_sha_init(sha, 160);
av_sha_update(sha, (const uint8_t *)buffer, sizeof(buffer));
av_sha_final(sha, digest);
return AV_RB32(digest) + AV_RB32(digest + 16);
}
uint32_t av_get_random_seed(void)
{
uint32_t seed;
#if HAVE_CRYPTGENRANDOM
HCRYPTPROV provider;
if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
BOOL ret = CryptGenRandom(provider, sizeof(seed), (PBYTE) &seed);
CryptReleaseContext(provider, 0);
if (ret)
return seed;
}
#endif
#if HAVE_ARC4RANDOM
return arc4random();
#endif
if (read_random(&seed, "/dev/urandom") == sizeof(seed))
return seed;
if (read_random(&seed, "/dev/random") == sizeof(seed))
return seed;
return get_generic_seed();
}
|
