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FFmpeg/libavutil/random_seed.c
Steve Lhomme abf806f7f1 random_seed: use bcrypt instead of the old wincrypt API
Remove the wincrypt API calls since we don't support XP anymore and
bcrypt is available since Vista, even on Windows Store builds.

Signed-off-by: Martin Storsjö <martin@martin.st>
2018-04-19 10:54:26 +03:00

117 lines
3.1 KiB
C

/*
* Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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_BCRYPT
#include <windows.h>
#include <bcrypt.h>
#endif
#include <fcntl.h>
#include <math.h>
#include <time.h>
#include "internal.h"
#include "intreadwrite.h"
#include "mem.h"
#include "timer.h"
#include "random_seed.h"
#include "sha.h"
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)
{
struct AVSHA *sha = av_sha_alloc();
clock_t last_t = 0;
static uint64_t i = 0;
static uint32_t buffer[512] = { 0 };
unsigned char digest[20];
uint64_t last_i = i;
for (;;) {
clock_t t = clock();
if (last_t == t) {
buffer[i & 511]++;
} else {
buffer[++i & 511] += (t - last_t) % 3294638521U;
if (last_i && i - last_i > 4 || i - last_i > 64)
break;
}
last_t = t;
}
if (!sha) {
uint32_t seed = 0;
int j;
// Unable to allocate an SHA context, just XOR the buffer together
// to create something hopefully unique.
for (j = 0; j < 512; j++)
seed ^= buffer[j];
return seed;
}
av_sha_init(sha, 160);
av_sha_update(sha, (const uint8_t *) buffer, sizeof(buffer));
av_sha_final(sha, digest);
av_free(sha);
return AV_RB32(digest) + AV_RB32(digest + 16);
}
uint32_t av_get_random_seed(void)
{
uint32_t seed;
#if HAVE_BCRYPT
BCRYPT_ALG_HANDLE algo_handle;
NTSTATUS ret = BCryptOpenAlgorithmProvider(&algo_handle, BCRYPT_RNG_ALGORITHM,
MS_PRIMITIVE_PROVIDER, 0);
if (BCRYPT_SUCCESS(ret)) {
NTSTATUS ret = BCryptGenRandom(algo_handle, (UCHAR*)&seed, sizeof(seed), 0);
BCryptCloseAlgorithmProvider(algo_handle, 0);
if (BCRYPT_SUCCESS(ret))
return seed;
}
#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();
}