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 <stdint.h>
20 #include <string.h>
21
22 #include "atomic.h"
23 #include "buffer_internal.h"
24 #include "common.h"
25 #include "mem.h"
26 #include "thread.h"
27
av_buffer_create(uint8_t * data,int size,void (* free)(void * opaque,uint8_t * data),void * opaque,int flags)28 AVBufferRef *av_buffer_create(uint8_t *data, int size,
29 void (*free)(void *opaque, uint8_t *data),
30 void *opaque, int flags)
31 {
32 AVBufferRef *ref = NULL;
33 AVBuffer *buf = NULL;
34
35 buf = av_mallocz(sizeof(*buf));
36 if (!buf)
37 return NULL;
38
39 buf->data = data;
40 buf->size = size;
41 buf->free = free ? free : av_buffer_default_free;
42 buf->opaque = opaque;
43 buf->refcount = 1;
44
45 if (flags & AV_BUFFER_FLAG_READONLY)
46 buf->flags |= BUFFER_FLAG_READONLY;
47
48 ref = av_mallocz(sizeof(*ref));
49 if (!ref) {
50 av_freep(&buf);
51 return NULL;
52 }
53
54 ref->buffer = buf;
55 ref->data = data;
56 ref->size = size;
57
58 return ref;
59 }
60
av_buffer_default_free(void * opaque,uint8_t * data)61 void av_buffer_default_free(void *opaque, uint8_t *data)
62 {
63 av_free(data);
64 }
65
av_buffer_alloc(int size)66 AVBufferRef *av_buffer_alloc(int size)
67 {
68 AVBufferRef *ret = NULL;
69 uint8_t *data = NULL;
70
71 data = av_malloc(size);
72 if (!data)
73 return NULL;
74
75 ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
76 if (!ret)
77 av_freep(&data);
78
79 return ret;
80 }
81
av_buffer_allocz(int size)82 AVBufferRef *av_buffer_allocz(int size)
83 {
84 AVBufferRef *ret = av_buffer_alloc(size);
85 if (!ret)
86 return NULL;
87
88 memset(ret->data, 0, size);
89 return ret;
90 }
91
av_buffer_ref(AVBufferRef * buf)92 AVBufferRef *av_buffer_ref(AVBufferRef *buf)
93 {
94 AVBufferRef *ret = av_mallocz(sizeof(*ret));
95
96 if (!ret)
97 return NULL;
98
99 *ret = *buf;
100
101 avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1);
102
103 return ret;
104 }
105
buffer_replace(AVBufferRef ** dst,AVBufferRef ** src)106 static void buffer_replace(AVBufferRef **dst, AVBufferRef **src)
107 {
108 AVBuffer *b;
109
110 b = (*dst)->buffer;
111
112 if (src) {
113 **dst = **src;
114 av_freep(src);
115 } else
116 av_freep(dst);
117
118 if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {
119 b->free(b->opaque, b->data);
120 av_freep(&b);
121 }
122 }
123
av_buffer_unref(AVBufferRef ** buf)124 void av_buffer_unref(AVBufferRef **buf)
125 {
126 if (!buf || !*buf)
127 return;
128
129 buffer_replace(buf, NULL);
130 }
131
av_buffer_is_writable(const AVBufferRef * buf)132 int av_buffer_is_writable(const AVBufferRef *buf)
133 {
134 if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)
135 return 0;
136
137 return avpriv_atomic_int_get(&buf->buffer->refcount) == 1;
138 }
139
av_buffer_get_opaque(const AVBufferRef * buf)140 void *av_buffer_get_opaque(const AVBufferRef *buf)
141 {
142 return buf->buffer->opaque;
143 }
144
av_buffer_get_ref_count(const AVBufferRef * buf)145 int av_buffer_get_ref_count(const AVBufferRef *buf)
146 {
147 return buf->buffer->refcount;
148 }
149
av_buffer_make_writable(AVBufferRef ** pbuf)150 int av_buffer_make_writable(AVBufferRef **pbuf)
151 {
152 AVBufferRef *newbuf, *buf = *pbuf;
153
154 if (av_buffer_is_writable(buf))
155 return 0;
156
157 newbuf = av_buffer_alloc(buf->size);
158 if (!newbuf)
159 return AVERROR(ENOMEM);
160
161 memcpy(newbuf->data, buf->data, buf->size);
162
163 buffer_replace(pbuf, &newbuf);
164
165 return 0;
166 }
167
av_buffer_realloc(AVBufferRef ** pbuf,int size)168 int av_buffer_realloc(AVBufferRef **pbuf, int size)
169 {
170 AVBufferRef *buf = *pbuf;
171 uint8_t *tmp;
172
173 if (!buf) {
174 /* allocate a new buffer with av_realloc(), so it will be reallocatable
175 * later */
176 uint8_t *data = av_realloc(NULL, size);
177 if (!data)
178 return AVERROR(ENOMEM);
179
180 buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
181 if (!buf) {
182 av_freep(&data);
183 return AVERROR(ENOMEM);
184 }
185
186 buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE;
187 *pbuf = buf;
188
189 return 0;
190 } else if (buf->size == size)
191 return 0;
192
193 if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) ||
194 !av_buffer_is_writable(buf)) {
195 /* cannot realloc, allocate a new reallocable buffer and copy data */
196 AVBufferRef *new = NULL;
197
198 av_buffer_realloc(&new, size);
199 if (!new)
200 return AVERROR(ENOMEM);
201
202 memcpy(new->data, buf->data, FFMIN(size, buf->size));
203
204 buffer_replace(pbuf, &new);
205 return 0;
206 }
207
208 tmp = av_realloc(buf->buffer->data, size);
209 if (!tmp)
210 return AVERROR(ENOMEM);
211
212 buf->buffer->data = buf->data = tmp;
213 buf->buffer->size = buf->size = size;
214 return 0;
215 }
216
av_buffer_pool_init2(int size,void * opaque,AVBufferRef * (* alloc)(void * opaque,int size),void (* pool_free)(void * opaque))217 AVBufferPool *av_buffer_pool_init2(int size, void *opaque,
218 AVBufferRef* (*alloc)(void *opaque, int size),
219 void (*pool_free)(void *opaque))
220 {
221 AVBufferPool *pool = av_mallocz(sizeof(*pool));
222 if (!pool)
223 return NULL;
224
225 ff_mutex_init(&pool->mutex, NULL);
226
227 pool->size = size;
228 pool->opaque = opaque;
229 pool->alloc2 = alloc;
230 pool->pool_free = pool_free;
231
232 avpriv_atomic_int_set(&pool->refcount, 1);
233
234 return pool;
235 }
236
av_buffer_pool_init(int size,AVBufferRef * (* alloc)(int size))237 AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size))
238 {
239 AVBufferPool *pool = av_mallocz(sizeof(*pool));
240 if (!pool)
241 return NULL;
242
243 ff_mutex_init(&pool->mutex, NULL);
244
245 pool->size = size;
246 pool->alloc = alloc ? alloc : av_buffer_alloc;
247
248 avpriv_atomic_int_set(&pool->refcount, 1);
249
250 return pool;
251 }
252
253 /*
254 * This function gets called when the pool has been uninited and
255 * all the buffers returned to it.
256 */
buffer_pool_free(AVBufferPool * pool)257 static void buffer_pool_free(AVBufferPool *pool)
258 {
259 while (pool->pool) {
260 BufferPoolEntry *buf = pool->pool;
261 pool->pool = buf->next;
262
263 buf->free(buf->opaque, buf->data);
264 av_freep(&buf);
265 }
266 ff_mutex_destroy(&pool->mutex);
267
268 if (pool->pool_free)
269 pool->pool_free(pool->opaque);
270
271 av_freep(&pool);
272 }
273
av_buffer_pool_uninit(AVBufferPool ** ppool)274 void av_buffer_pool_uninit(AVBufferPool **ppool)
275 {
276 AVBufferPool *pool;
277
278 if (!ppool || !*ppool)
279 return;
280 pool = *ppool;
281 *ppool = NULL;
282
283 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
284 buffer_pool_free(pool);
285 }
286
287 #if USE_ATOMICS
288 /* remove the whole buffer list from the pool and return it */
get_pool(AVBufferPool * pool)289 static BufferPoolEntry *get_pool(AVBufferPool *pool)
290 {
291 BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL;
292
293 while (cur != last) {
294 last = cur;
295 cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL);
296 if (!cur)
297 return NULL;
298 }
299
300 return cur;
301 }
302
add_to_pool(BufferPoolEntry * buf)303 static void add_to_pool(BufferPoolEntry *buf)
304 {
305 AVBufferPool *pool;
306 BufferPoolEntry *cur, *end = buf;
307
308 if (!buf)
309 return;
310 pool = buf->pool;
311
312 while (end->next)
313 end = end->next;
314
315 while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) {
316 /* pool is not empty, retrieve it and append it to our list */
317 cur = get_pool(pool);
318 end->next = cur;
319 while (end->next)
320 end = end->next;
321 }
322 }
323 #endif
324
pool_release_buffer(void * opaque,uint8_t * data)325 static void pool_release_buffer(void *opaque, uint8_t *data)
326 {
327 BufferPoolEntry *buf = opaque;
328 AVBufferPool *pool = buf->pool;
329
330 if(CONFIG_MEMORY_POISONING)
331 memset(buf->data, FF_MEMORY_POISON, pool->size);
332
333 #if USE_ATOMICS
334 add_to_pool(buf);
335 #else
336 ff_mutex_lock(&pool->mutex);
337 buf->next = pool->pool;
338 pool->pool = buf;
339 ff_mutex_unlock(&pool->mutex);
340 #endif
341
342 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
343 buffer_pool_free(pool);
344 }
345
346 /* allocate a new buffer and override its free() callback so that
347 * it is returned to the pool on free */
pool_alloc_buffer(AVBufferPool * pool)348 static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
349 {
350 BufferPoolEntry *buf;
351 AVBufferRef *ret;
352
353 ret = pool->alloc2 ? pool->alloc2(pool->opaque, pool->size) :
354 pool->alloc(pool->size);
355 if (!ret)
356 return NULL;
357
358 buf = av_mallocz(sizeof(*buf));
359 if (!buf) {
360 av_buffer_unref(&ret);
361 return NULL;
362 }
363
364 buf->data = ret->buffer->data;
365 buf->opaque = ret->buffer->opaque;
366 buf->free = ret->buffer->free;
367 buf->pool = pool;
368
369 ret->buffer->opaque = buf;
370 ret->buffer->free = pool_release_buffer;
371
372 #if USE_ATOMICS
373 avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
374 avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1);
375 #endif
376
377 return ret;
378 }
379
av_buffer_pool_get(AVBufferPool * pool)380 AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
381 {
382 AVBufferRef *ret;
383 BufferPoolEntry *buf;
384
385 #if USE_ATOMICS
386 /* check whether the pool is empty */
387 buf = get_pool(pool);
388 if (!buf && pool->refcount <= pool->nb_allocated) {
389 av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n");
390 while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated))
391 buf = get_pool(pool);
392 }
393
394 if (!buf)
395 return pool_alloc_buffer(pool);
396
397 /* keep the first entry, return the rest of the list to the pool */
398 add_to_pool(buf->next);
399 buf->next = NULL;
400
401 ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
402 buf, 0);
403 if (!ret) {
404 add_to_pool(buf);
405 return NULL;
406 }
407 #else
408 ff_mutex_lock(&pool->mutex);
409 buf = pool->pool;
410 if (buf) {
411 ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
412 buf, 0);
413 if (ret) {
414 pool->pool = buf->next;
415 buf->next = NULL;
416 }
417 } else {
418 ret = pool_alloc_buffer(pool);
419 }
420 ff_mutex_unlock(&pool->mutex);
421 #endif
422
423 if (ret)
424 avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
425
426 return ret;
427 }
428