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38e23c88db
Attempt to read from /dev/urandom and /dev/random with O_NONBLOCK set. If neither succeeds, proceed with fallbacks. Originally committed as revision 23903 to svn://svn.ffmpeg.org/ffmpeg/trunk
68 lines
1.7 KiB
C
68 lines
1.7 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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#include <unistd.h>
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#include <fcntl.h>
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#include "timer.h"
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#include "random_seed.h"
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#include "avutil.h"
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static int read_random(uint32_t *dst, const char *file)
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{
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int fd = 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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#if HAVE_FCNTL && defined(O_NONBLOCK)
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if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK) != -1)
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#endif
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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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}
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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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int err;
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err = read_random(&seed, "/dev/urandom");
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if (err != sizeof(seed))
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err = read_random(&seed, "/dev/random");
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if (err == sizeof(seed))
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return seed;
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#ifdef AV_READ_TIME
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seed = AV_READ_TIME();
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#endif
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// XXX what to do ?
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return seed;
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}
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#if LIBAVUTIL_VERSION_MAJOR < 51
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attribute_deprecated uint32_t ff_random_get_seed(void);
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uint32_t ff_random_get_seed(void)
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{
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return av_get_random_seed();
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}
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#endif
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