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144 lines
3.6 KiB
144 lines
3.6 KiB
/* |
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* Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "config.h" |
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#if HAVE_UNISTD_H |
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#include <unistd.h> |
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#endif |
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#if HAVE_IO_H |
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#include <io.h> |
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#endif |
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#if HAVE_CRYPTGENRANDOM |
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#include <windows.h> |
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#include <wincrypt.h> |
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#endif |
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#include <fcntl.h> |
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#include <math.h> |
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#include <time.h> |
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#include <string.h> |
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#include "avassert.h" |
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#include "internal.h" |
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#include "intreadwrite.h" |
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#include "timer.h" |
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#include "random_seed.h" |
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#include "sha.h" |
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#ifndef TEST |
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#define TEST 0 |
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#endif |
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static int read_random(uint32_t *dst, const char *file) |
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{ |
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#if HAVE_UNISTD_H |
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int fd = avpriv_open(file, O_RDONLY); |
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int err = -1; |
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if (fd == -1) |
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return -1; |
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err = read(fd, dst, sizeof(*dst)); |
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close(fd); |
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return err; |
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#else |
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return -1; |
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#endif |
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} |
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static uint32_t get_generic_seed(void) |
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{ |
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uint64_t tmp[120/8]; |
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struct AVSHA *sha = (void*)tmp; |
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clock_t last_t = 0; |
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clock_t last_td = 0; |
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clock_t init_t = 0; |
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static uint64_t i = 0; |
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static uint32_t buffer[512] = { 0 }; |
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unsigned char digest[20]; |
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uint64_t last_i = i; |
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av_assert0(sizeof(tmp) >= av_sha_size); |
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if(TEST){ |
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memset(buffer, 0, sizeof(buffer)); |
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last_i = i = 0; |
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}else{ |
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#ifdef AV_READ_TIME |
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buffer[13] ^= AV_READ_TIME(); |
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buffer[41] ^= AV_READ_TIME()>>32; |
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#endif |
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} |
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for (;;) { |
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clock_t t = clock(); |
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if (last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t) { |
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last_td = t - last_t; |
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buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U); |
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} else { |
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last_td = t - last_t; |
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buffer[++i & 511] += last_td % 3294638521U; |
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if ((t - init_t) >= CLOCKS_PER_SEC>>5) |
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if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) |
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break; |
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} |
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last_t = t; |
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if (!init_t) |
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init_t = t; |
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} |
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if(TEST) { |
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buffer[0] = buffer[1] = 0; |
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} else { |
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#ifdef AV_READ_TIME |
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buffer[111] += AV_READ_TIME(); |
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#endif |
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} |
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av_sha_init(sha, 160); |
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av_sha_update(sha, (const uint8_t *)buffer, sizeof(buffer)); |
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av_sha_final(sha, digest); |
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return AV_RB32(digest) + AV_RB32(digest + 16); |
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} |
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uint32_t av_get_random_seed(void) |
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{ |
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uint32_t seed; |
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#if HAVE_CRYPTGENRANDOM |
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HCRYPTPROV provider; |
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if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, |
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CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) { |
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BOOL ret = CryptGenRandom(provider, sizeof(seed), (PBYTE) &seed); |
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CryptReleaseContext(provider, 0); |
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if (ret) |
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return seed; |
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} |
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#endif |
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#if HAVE_ARC4RANDOM |
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return arc4random(); |
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#endif |
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if (read_random(&seed, "/dev/urandom") == sizeof(seed)) |
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return seed; |
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if (read_random(&seed, "/dev/random") == sizeof(seed)) |
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return seed; |
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return get_generic_seed(); |
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}
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