2 * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
29 #if HAVE_CRYPTGENRANDOM
39 #include "intreadwrite.h"
41 #include "random_seed.h"
48 static int read_random(uint32_t *dst
, const char *file
)
51 int fd
= avpriv_open(file
, O_RDONLY
);
56 err
= read(fd
, dst
, sizeof(*dst
));
65 static uint32_t get_generic_seed(void)
68 struct AVSHA
*sha
= (void*)tmp
;
70 static uint64_t i
= 0;
71 static uint32_t buffer
[512] = { 0 };
72 unsigned char digest
[20];
75 av_assert0(sizeof(tmp
) >= av_sha_size
);
78 memset(buffer
, 0, sizeof(buffer
));
82 buffer
[13] ^= AV_READ_TIME();
83 buffer
[41] ^= AV_READ_TIME()>>32;
93 buffer
[++i
& 511] += (t
- last_t
) % 3294638521U;
94 if (last_i
&& i
- last_i
> 4 || i
- last_i
> 64 || TEST
&& i
- last_i
> 8)
101 buffer
[0] = buffer
[1] = 0;
103 av_sha_init(sha
, 160);
104 av_sha_update(sha
, (const uint8_t *)buffer
, sizeof(buffer
));
105 av_sha_final(sha
, digest
);
106 return AV_RB32(digest
) + AV_RB32(digest
+ 16);
109 uint32_t av_get_random_seed(void)
113 #if HAVE_CRYPTGENRANDOM
115 if (CryptAcquireContext(&provider
, NULL
, NULL
, PROV_RSA_FULL
,
116 CRYPT_VERIFYCONTEXT
| CRYPT_SILENT
)) {
117 BOOL ret
= CryptGenRandom(provider
, sizeof(seed
), (PBYTE
) &seed
);
118 CryptReleaseContext(provider
, 0);
124 if (read_random(&seed
, "/dev/urandom") == sizeof(seed
))
126 if (read_random(&seed
, "/dev/random") == sizeof(seed
))
128 return get_generic_seed();
141 for (retry
=0; retry
<3; retry
++){
143 seeds
[i
] = av_get_random_seed();
145 if (seeds
[j
] == seeds
[i
])
148 printf("seeds OK\n");
152 printf("FAIL at %d with %X\n", j
, seeds
[j
]);