cea3a63ba3
This race will always happen sooner or later in a multi-threaded environment and it will over time lead to OOM. This fix works by spinning, there are other ways by which this can be fixed, like simply detecting the issue after it happened and freeing the over-allocated memory or simply using a mutex. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
95 lines
2.6 KiB
C
95 lines
2.6 KiB
C
/*
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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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#ifndef AVUTIL_BUFFER_INTERNAL_H
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#define AVUTIL_BUFFER_INTERNAL_H
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#include <stdint.h>
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#include "buffer.h"
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/**
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* The buffer is always treated as read-only.
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*/
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#define BUFFER_FLAG_READONLY (1 << 0)
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/**
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* The buffer was av_realloc()ed, so it is reallocatable.
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*/
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#define BUFFER_FLAG_REALLOCATABLE (1 << 1)
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struct AVBuffer {
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uint8_t *data; /**< data described by this buffer */
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int size; /**< size of data in bytes */
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/**
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* number of existing AVBufferRef instances referring to this buffer
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*/
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volatile int refcount;
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/**
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* a callback for freeing the data
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*/
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void (*free)(void *opaque, uint8_t *data);
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/**
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* an opaque pointer, to be used by the freeing callback
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*/
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void *opaque;
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/**
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* A combination of BUFFER_FLAG_*
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*/
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int flags;
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};
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typedef struct BufferPoolEntry {
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uint8_t *data;
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/*
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* Backups of the original opaque/free of the AVBuffer corresponding to
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* data. They will be used to free the buffer when the pool is freed.
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*/
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void *opaque;
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void (*free)(void *opaque, uint8_t *data);
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AVBufferPool *pool;
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struct BufferPoolEntry * volatile next;
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} BufferPoolEntry;
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struct AVBufferPool {
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BufferPoolEntry * volatile pool;
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/*
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* This is used to track when the pool is to be freed.
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* The pointer to the pool itself held by the caller is considered to
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* be one reference. Each buffer requested by the caller increases refcount
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* by one, returning the buffer to the pool decreases it by one.
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* refcount reaches zero when the buffer has been uninited AND all the
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* buffers have been released, then it's safe to free the pool and all
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* the buffers in it.
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*/
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volatile int refcount;
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volatile int nb_allocated;
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int size;
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AVBufferRef* (*alloc)(int size);
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};
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#endif /* AVUTIL_BUFFER_INTERNAL_H */
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