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	579a137897
	
	
	
		
			
			* commit '880391ed2d2faf796ca3a16f63cec69767546a21': libavutil: use avpriv_open() Conflicts: libavutil/random_seed.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
		
			
				
	
	
		
			153 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			153 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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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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| 
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| #include "config.h"
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| 
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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_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 "timer.h"
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| #include "random_seed.h"
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| #include "sha.h"
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| #include "intreadwrite.h"
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| 
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| #ifndef TEST
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| #define TEST 0
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| #endif
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| 
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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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| 
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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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| 
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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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| 
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| static uint32_t get_generic_seed(void)
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| {
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|     uint8_t tmp[120];
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|     struct AVSHA *sha = (void*)tmp;
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|     clock_t last_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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| 
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|     av_assert0(sizeof(tmp) >= av_sha_size);
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| 
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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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| 
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|     for (;;) {
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|         clock_t t = clock();
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| 
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|         if(last_t == t){
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|             buffer[i&511]++;
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|         }else{
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|             buffer[++i&511]+= (t-last_t) % 3294638521U;
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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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|     }
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| 
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|     if(TEST)
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|         buffer[0] = buffer[1] = 0;
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| 
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|     av_sha_init(sha, 160);
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|     av_sha_update(sha, (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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| 
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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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| 
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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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| 
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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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| 
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| #if TEST
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| #undef printf
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| #define N 256
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| #include <stdio.h>
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| 
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| int main(void)
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| {
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|     int i, j, retry;
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|     uint32_t seeds[N];
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| 
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|     for (retry=0; retry<3; retry++){
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|         for (i=0; i<N; i++){
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|             seeds[i] = av_get_random_seed();
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|             for (j=0; j<i; j++)
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|                 if (seeds[j] == seeds[i])
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|                     goto retry;
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|         }
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|         printf("seeds OK\n");
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|         return 0;
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|         retry:;
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|     }
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|     printf("FAIL at %d with %X\n", j, seeds[j]);
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|     return 1;
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| }
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| #endif
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