1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #include <stdatomic.h>
20 #include <stdint.h>
21 #include <string.h>
22
23 #include "avassert.h"
24 #include "buffer_internal.h"
25 #include "common.h"
26 #include "mem.h"
27 #include "thread.h"
28
buffer_create(AVBuffer * buf,uint8_t * data,size_t size,void (* free)(void * opaque,uint8_t * data),void * opaque,int flags)29 static AVBufferRef *buffer_create(AVBuffer *buf, uint8_t *data, size_t size,
30 void (*free)(void *opaque, uint8_t *data),
31 void *opaque, int flags)
32 {
33 AVBufferRef *ref = NULL;
34
35 buf->data = data;
36 buf->size = size;
37 buf->free = free ? free : av_buffer_default_free;
38 buf->opaque = opaque;
39
40 atomic_init(&buf->refcount, 1);
41
42 buf->flags = flags;
43
44 ref = av_mallocz(sizeof(*ref));
45 if (!ref)
46 return NULL;
47
48 ref->buffer = buf;
49 ref->data = data;
50 ref->size = size;
51
52 return ref;
53 }
54
av_buffer_create(uint8_t * data,size_t size,void (* free)(void * opaque,uint8_t * data),void * opaque,int flags)55 AVBufferRef *av_buffer_create(uint8_t *data, size_t size,
56 void (*free)(void *opaque, uint8_t *data),
57 void *opaque, int flags)
58 {
59 AVBufferRef *ret;
60 AVBuffer *buf = av_mallocz(sizeof(*buf));
61 if (!buf)
62 return NULL;
63
64 ret = buffer_create(buf, data, size, free, opaque, flags);
65 if (!ret) {
66 av_free(buf);
67 return NULL;
68 }
69 return ret;
70 }
71
av_buffer_default_free(void * opaque,uint8_t * data)72 void av_buffer_default_free(void *opaque, uint8_t *data)
73 {
74 av_free(data);
75 }
76
av_buffer_alloc(size_t size)77 AVBufferRef *av_buffer_alloc(size_t size)
78 {
79 AVBufferRef *ret = NULL;
80 uint8_t *data = NULL;
81
82 data = av_malloc(size);
83 if (!data)
84 return NULL;
85
86 ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
87 if (!ret)
88 av_freep(&data);
89
90 return ret;
91 }
92
av_buffer_allocz(size_t size)93 AVBufferRef *av_buffer_allocz(size_t size)
94 {
95 AVBufferRef *ret = av_buffer_alloc(size);
96 if (!ret)
97 return NULL;
98
99 memset(ret->data, 0, size);
100 return ret;
101 }
102
av_buffer_ref(const AVBufferRef * buf)103 AVBufferRef *av_buffer_ref(const AVBufferRef *buf)
104 {
105 AVBufferRef *ret = av_mallocz(sizeof(*ret));
106
107 if (!ret)
108 return NULL;
109
110 *ret = *buf;
111
112 atomic_fetch_add_explicit(&buf->buffer->refcount, 1, memory_order_relaxed);
113
114 return ret;
115 }
116
buffer_replace(AVBufferRef ** dst,AVBufferRef ** src)117 static void buffer_replace(AVBufferRef **dst, AVBufferRef **src)
118 {
119 AVBuffer *b;
120
121 b = (*dst)->buffer;
122
123 if (src) {
124 **dst = **src;
125 av_freep(src);
126 } else
127 av_freep(dst);
128
129 if (atomic_fetch_sub_explicit(&b->refcount, 1, memory_order_acq_rel) == 1) {
130 /* b->free below might already free the structure containing *b,
131 * so we have to read the flag now to avoid use-after-free. */
132 int free_avbuffer = !(b->flags_internal & BUFFER_FLAG_NO_FREE);
133 b->free(b->opaque, b->data);
134 if (free_avbuffer)
135 av_free(b);
136 }
137 }
138
av_buffer_unref(AVBufferRef ** buf)139 void av_buffer_unref(AVBufferRef **buf)
140 {
141 if (!buf || !*buf)
142 return;
143
144 buffer_replace(buf, NULL);
145 }
146
av_buffer_is_writable(const AVBufferRef * buf)147 int av_buffer_is_writable(const AVBufferRef *buf)
148 {
149 if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)
150 return 0;
151
152 return atomic_load(&buf->buffer->refcount) == 1;
153 }
154
av_buffer_get_opaque(const AVBufferRef * buf)155 void *av_buffer_get_opaque(const AVBufferRef *buf)
156 {
157 return buf->buffer->opaque;
158 }
159
av_buffer_get_ref_count(const AVBufferRef * buf)160 int av_buffer_get_ref_count(const AVBufferRef *buf)
161 {
162 return atomic_load(&buf->buffer->refcount);
163 }
164
av_buffer_make_writable(AVBufferRef ** pbuf)165 int av_buffer_make_writable(AVBufferRef **pbuf)
166 {
167 AVBufferRef *newbuf, *buf = *pbuf;
168
169 if (av_buffer_is_writable(buf))
170 return 0;
171
172 newbuf = av_buffer_alloc(buf->size);
173 if (!newbuf)
174 return AVERROR(ENOMEM);
175
176 memcpy(newbuf->data, buf->data, buf->size);
177
178 buffer_replace(pbuf, &newbuf);
179
180 return 0;
181 }
182
av_buffer_realloc(AVBufferRef ** pbuf,size_t size)183 int av_buffer_realloc(AVBufferRef **pbuf, size_t size)
184 {
185 AVBufferRef *buf = *pbuf;
186 uint8_t *tmp;
187 int ret;
188
189 if (!buf) {
190 /* allocate a new buffer with av_realloc(), so it will be reallocatable
191 * later */
192 uint8_t *data = av_realloc(NULL, size);
193 if (!data)
194 return AVERROR(ENOMEM);
195
196 buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
197 if (!buf) {
198 av_freep(&data);
199 return AVERROR(ENOMEM);
200 }
201
202 buf->buffer->flags_internal |= BUFFER_FLAG_REALLOCATABLE;
203 *pbuf = buf;
204
205 return 0;
206 } else if (buf->size == size)
207 return 0;
208
209 if (!(buf->buffer->flags_internal & BUFFER_FLAG_REALLOCATABLE) ||
210 !av_buffer_is_writable(buf) || buf->data != buf->buffer->data) {
211 /* cannot realloc, allocate a new reallocable buffer and copy data */
212 AVBufferRef *new = NULL;
213
214 ret = av_buffer_realloc(&new, size);
215 if (ret < 0)
216 return ret;
217
218 memcpy(new->data, buf->data, FFMIN(size, buf->size));
219
220 buffer_replace(pbuf, &new);
221 return 0;
222 }
223
224 tmp = av_realloc(buf->buffer->data, size);
225 if (!tmp)
226 return AVERROR(ENOMEM);
227
228 buf->buffer->data = buf->data = tmp;
229 buf->buffer->size = buf->size = size;
230 return 0;
231 }
232
av_buffer_replace(AVBufferRef ** pdst,const AVBufferRef * src)233 int av_buffer_replace(AVBufferRef **pdst, const AVBufferRef *src)
234 {
235 AVBufferRef *dst = *pdst;
236 AVBufferRef *tmp;
237
238 if (!src) {
239 av_buffer_unref(pdst);
240 return 0;
241 }
242
243 if (dst && dst->buffer == src->buffer) {
244 /* make sure the data pointers match */
245 dst->data = src->data;
246 dst->size = src->size;
247 return 0;
248 }
249
250 tmp = av_buffer_ref(src);
251 if (!tmp)
252 return AVERROR(ENOMEM);
253
254 av_buffer_unref(pdst);
255 *pdst = tmp;
256 return 0;
257 }
258
av_buffer_pool_init2(size_t size,void * opaque,AVBufferRef * (* alloc)(void * opaque,size_t size),void (* pool_free)(void * opaque))259 AVBufferPool *av_buffer_pool_init2(size_t size, void *opaque,
260 AVBufferRef* (*alloc)(void *opaque, size_t size),
261 void (*pool_free)(void *opaque))
262 {
263 AVBufferPool *pool = av_mallocz(sizeof(*pool));
264 if (!pool)
265 return NULL;
266
267 ff_mutex_init(&pool->mutex, NULL);
268
269 pool->size = size;
270 pool->opaque = opaque;
271 pool->alloc2 = alloc;
272 pool->alloc = av_buffer_alloc; // fallback
273 pool->pool_free = pool_free;
274
275 atomic_init(&pool->refcount, 1);
276
277 return pool;
278 }
279
av_buffer_pool_init(size_t size,AVBufferRef * (* alloc)(size_t size))280 AVBufferPool *av_buffer_pool_init(size_t size, AVBufferRef* (*alloc)(size_t size))
281 {
282 AVBufferPool *pool = av_mallocz(sizeof(*pool));
283 if (!pool)
284 return NULL;
285
286 ff_mutex_init(&pool->mutex, NULL);
287
288 pool->size = size;
289 pool->alloc = alloc ? alloc : av_buffer_alloc;
290
291 atomic_init(&pool->refcount, 1);
292
293 return pool;
294 }
295
buffer_pool_flush(AVBufferPool * pool)296 static void buffer_pool_flush(AVBufferPool *pool)
297 {
298 while (pool->pool) {
299 BufferPoolEntry *buf = pool->pool;
300 pool->pool = buf->next;
301
302 buf->free(buf->opaque, buf->data);
303 av_freep(&buf);
304 }
305 }
306
307 /*
308 * This function gets called when the pool has been uninited and
309 * all the buffers returned to it.
310 */
buffer_pool_free(AVBufferPool * pool)311 static void buffer_pool_free(AVBufferPool *pool)
312 {
313 buffer_pool_flush(pool);
314 ff_mutex_destroy(&pool->mutex);
315
316 if (pool->pool_free)
317 pool->pool_free(pool->opaque);
318
319 av_freep(&pool);
320 }
321
av_buffer_pool_uninit(AVBufferPool ** ppool)322 void av_buffer_pool_uninit(AVBufferPool **ppool)
323 {
324 AVBufferPool *pool;
325
326 if (!ppool || !*ppool)
327 return;
328 pool = *ppool;
329 *ppool = NULL;
330
331 ff_mutex_lock(&pool->mutex);
332 buffer_pool_flush(pool);
333 ff_mutex_unlock(&pool->mutex);
334
335 if (atomic_fetch_sub_explicit(&pool->refcount, 1, memory_order_acq_rel) == 1)
336 buffer_pool_free(pool);
337 }
338
pool_release_buffer(void * opaque,uint8_t * data)339 static void pool_release_buffer(void *opaque, uint8_t *data)
340 {
341 BufferPoolEntry *buf = opaque;
342 AVBufferPool *pool = buf->pool;
343
344 if(CONFIG_MEMORY_POISONING)
345 memset(buf->data, FF_MEMORY_POISON, pool->size);
346
347 ff_mutex_lock(&pool->mutex);
348 buf->next = pool->pool;
349 pool->pool = buf;
350 ff_mutex_unlock(&pool->mutex);
351
352 if (atomic_fetch_sub_explicit(&pool->refcount, 1, memory_order_acq_rel) == 1)
353 buffer_pool_free(pool);
354 }
355
356 /* allocate a new buffer and override its free() callback so that
357 * it is returned to the pool on free */
pool_alloc_buffer(AVBufferPool * pool)358 static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
359 {
360 BufferPoolEntry *buf;
361 AVBufferRef *ret;
362
363 av_assert0(pool->alloc || pool->alloc2);
364
365 ret = pool->alloc2 ? pool->alloc2(pool->opaque, pool->size) :
366 pool->alloc(pool->size);
367 if (!ret)
368 return NULL;
369
370 buf = av_mallocz(sizeof(*buf));
371 if (!buf) {
372 av_buffer_unref(&ret);
373 return NULL;
374 }
375
376 buf->data = ret->buffer->data;
377 buf->opaque = ret->buffer->opaque;
378 buf->free = ret->buffer->free;
379 buf->pool = pool;
380
381 ret->buffer->opaque = buf;
382 ret->buffer->free = pool_release_buffer;
383
384 return ret;
385 }
386
av_buffer_pool_get(AVBufferPool * pool)387 AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
388 {
389 AVBufferRef *ret;
390 BufferPoolEntry *buf;
391
392 ff_mutex_lock(&pool->mutex);
393 buf = pool->pool;
394 if (buf) {
395 memset(&buf->buffer, 0, sizeof(buf->buffer));
396 ret = buffer_create(&buf->buffer, buf->data, pool->size,
397 pool_release_buffer, buf, 0);
398 if (ret) {
399 pool->pool = buf->next;
400 buf->next = NULL;
401 buf->buffer.flags_internal |= BUFFER_FLAG_NO_FREE;
402 }
403 } else {
404 ret = pool_alloc_buffer(pool);
405 }
406 ff_mutex_unlock(&pool->mutex);
407
408 if (ret)
409 atomic_fetch_add_explicit(&pool->refcount, 1, memory_order_relaxed);
410
411 return ret;
412 }
413
av_buffer_pool_buffer_get_opaque(const AVBufferRef * ref)414 void *av_buffer_pool_buffer_get_opaque(const AVBufferRef *ref)
415 {
416 BufferPoolEntry *buf = ref->buffer->opaque;
417 av_assert0(buf);
418 return buf->opaque;
419 }
420