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avio.c
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1 /*
2  * unbuffered I/O
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/avstring.h"
23 #include "libavutil/dict.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/time.h"
26 #include "os_support.h"
27 #include "avformat.h"
28 #if CONFIG_NETWORK
29 #include "network.h"
30 #endif
31 #include "url.h"
32 
34 
36 {
37  return prev ? prev->next : first_protocol;
38 }
39 
40 /** @name Logging context. */
41 /*@{*/
42 static const char *urlcontext_to_name(void *ptr)
43 {
44  URLContext *h = (URLContext *)ptr;
45  if(h->prot) return h->prot->name;
46  else return "NULL";
47 }
48 
49 static void *urlcontext_child_next(void *obj, void *prev)
50 {
51  URLContext *h = obj;
52  if (!prev && h->priv_data && h->prot->priv_data_class)
53  return h->priv_data;
54  return NULL;
55 }
56 
57 static const AVClass *urlcontext_child_class_next(const AVClass *prev)
58 {
59  URLProtocol *p = NULL;
60 
61  /* find the protocol that corresponds to prev */
62  while (prev && (p = ffurl_protocol_next(p)))
63  if (p->priv_data_class == prev)
64  break;
65 
66  /* find next protocol with priv options */
67  while (p = ffurl_protocol_next(p))
68  if (p->priv_data_class)
69  return p->priv_data_class;
70  return NULL;
71 
72 }
73 
74 static const AVOption options[] = {{NULL}};
76  .class_name = "URLContext",
77  .item_name = urlcontext_to_name,
78  .option = options,
79  .version = LIBAVUTIL_VERSION_INT,
80  .child_next = urlcontext_child_next,
81  .child_class_next = urlcontext_child_class_next,
82 };
83 /*@}*/
84 
85 
86 const char *avio_enum_protocols(void **opaque, int output)
87 {
88  URLProtocol *p;
89  *opaque = ffurl_protocol_next(*opaque);
90  if (!(p = *opaque)) return NULL;
91  if ((output && p->url_write) || (!output && p->url_read))
92  return p->name;
93  return avio_enum_protocols(opaque, output);
94 }
95 
97 {
98  URLProtocol **p;
99  if (size < sizeof(URLProtocol)) {
101  memcpy(temp, protocol, size);
102  protocol = temp;
103  }
104  p = &first_protocol;
105  while (*p != NULL) p = &(*p)->next;
106  *p = protocol;
107  protocol->next = NULL;
108  return 0;
109 }
110 
111 static int url_alloc_for_protocol (URLContext **puc, struct URLProtocol *up,
112  const char *filename, int flags,
113  const AVIOInterruptCB *int_cb)
114 {
115  URLContext *uc;
116  int err;
117 
118 #if CONFIG_NETWORK
120  return AVERROR(EIO);
121 #endif
122  if ((flags & AVIO_FLAG_READ) && !up->url_read) {
124  "Impossible to open the '%s' protocol for reading\n", up->name);
125  return AVERROR(EIO);
126  }
127  if ((flags & AVIO_FLAG_WRITE) && !up->url_write) {
129  "Impossible to open the '%s' protocol for writing\n", up->name);
130  return AVERROR(EIO);
131  }
132  uc = av_mallocz(sizeof(URLContext) + strlen(filename) + 1);
133  if (!uc) {
134  err = AVERROR(ENOMEM);
135  goto fail;
136  }
138  uc->filename = (char *) &uc[1];
139  strcpy(uc->filename, filename);
140  uc->prot = up;
141  uc->flags = flags;
142  uc->is_streamed = 0; /* default = not streamed */
143  uc->max_packet_size = 0; /* default: stream file */
144  if (up->priv_data_size) {
146  if (up->priv_data_class) {
147  int proto_len= strlen(up->name);
148  char *start = strchr(uc->filename, ',');
149  *(const AVClass**)uc->priv_data = up->priv_data_class;
151  if(!strncmp(up->name, uc->filename, proto_len) && uc->filename + proto_len == start){
152  int ret= 0;
153  char *p= start;
154  char sep= *++p;
155  char *key, *val;
156  p++;
157  while(ret >= 0 && (key= strchr(p, sep)) && p<key && (val = strchr(key+1, sep))){
158  *val= *key= 0;
159  ret= av_opt_set(uc->priv_data, p, key+1, 0);
160  if (ret == AVERROR_OPTION_NOT_FOUND)
161  av_log(uc, AV_LOG_ERROR, "Key '%s' not found.\n", p);
162  *val= *key= sep;
163  p= val+1;
164  }
165  if(ret<0 || p!=key){
166  av_log(uc, AV_LOG_ERROR, "Error parsing options string %s\n", start);
167  av_freep(&uc->priv_data);
168  av_freep(&uc);
169  err = AVERROR(EINVAL);
170  goto fail;
171  }
172  memmove(start, key+1, strlen(key));
173  }
174  }
175  }
176  if (int_cb)
177  uc->interrupt_callback = *int_cb;
178 
179  *puc = uc;
180  return 0;
181  fail:
182  *puc = NULL;
183 #if CONFIG_NETWORK
186 #endif
187  return err;
188 }
189 
191 {
192  int err =
193  uc->prot->url_open2 ? uc->prot->url_open2(uc, uc->filename, uc->flags, options) :
194  uc->prot->url_open(uc, uc->filename, uc->flags);
195  if (err)
196  return err;
197  uc->is_connected = 1;
198  //We must be careful here as ffurl_seek() could be slow, for example for http
199  if( (uc->flags & AVIO_FLAG_WRITE)
200  || !strcmp(uc->prot->name, "file"))
201  if(!uc->is_streamed && ffurl_seek(uc, 0, SEEK_SET) < 0)
202  uc->is_streamed= 1;
203  return 0;
204 }
205 
206 #define URL_SCHEME_CHARS \
207  "abcdefghijklmnopqrstuvwxyz" \
208  "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
209  "0123456789+-."
210 
211 int ffurl_alloc(URLContext **puc, const char *filename, int flags,
212  const AVIOInterruptCB *int_cb)
213 {
214  URLProtocol *up = NULL;
215  char proto_str[128], proto_nested[128], *ptr;
216  size_t proto_len = strspn(filename, URL_SCHEME_CHARS);
217 
218  if (!first_protocol) {
219  av_log(NULL, AV_LOG_WARNING, "No URL Protocols are registered. "
220  "Missing call to av_register_all()?\n");
221  }
222 
223  if (filename[proto_len] != ':' &&
224  (filename[proto_len] != ',' || !strchr(filename + proto_len + 1, ':')) ||
225  is_dos_path(filename))
226  strcpy(proto_str, "file");
227  else
228  av_strlcpy(proto_str, filename, FFMIN(proto_len+1, sizeof(proto_str)));
229 
230  if ((ptr = strchr(proto_str, ',')))
231  *ptr = '\0';
232  av_strlcpy(proto_nested, proto_str, sizeof(proto_nested));
233  if ((ptr = strchr(proto_nested, '+')))
234  *ptr = '\0';
235 
236  while (up = ffurl_protocol_next(up)) {
237  if (!strcmp(proto_str, up->name))
238  return url_alloc_for_protocol (puc, up, filename, flags, int_cb);
240  !strcmp(proto_nested, up->name))
241  return url_alloc_for_protocol (puc, up, filename, flags, int_cb);
242  }
243  *puc = NULL;
245 }
246 
247 int ffurl_open(URLContext **puc, const char *filename, int flags,
248  const AVIOInterruptCB *int_cb, AVDictionary **options)
249 {
250  int ret = ffurl_alloc(puc, filename, flags, int_cb);
251  if (ret)
252  return ret;
253  if (options && (*puc)->prot->priv_data_class &&
254  (ret = av_opt_set_dict((*puc)->priv_data, options)) < 0)
255  goto fail;
256  ret = ffurl_connect(*puc, options);
257  if (!ret)
258  return 0;
259 fail:
260  ffurl_close(*puc);
261  *puc = NULL;
262  return ret;
263 }
264 
265 static inline int retry_transfer_wrapper(URLContext *h, unsigned char *buf, int size, int size_min,
266  int (*transfer_func)(URLContext *h, unsigned char *buf, int size))
267 {
268  int ret, len;
269  int fast_retries = 5;
270  int64_t wait_since = 0;
271 
272  len = 0;
273  while (len < size_min) {
274  ret = transfer_func(h, buf+len, size-len);
275  if (ret == AVERROR(EINTR))
276  continue;
277  if (h->flags & AVIO_FLAG_NONBLOCK)
278  return ret;
279  if (ret == AVERROR(EAGAIN)) {
280  ret = 0;
281  if (fast_retries) {
282  fast_retries--;
283  } else {
284  if (h->rw_timeout) {
285  if (!wait_since)
286  wait_since = av_gettime();
287  else if (av_gettime() > wait_since + h->rw_timeout)
288  return AVERROR(EIO);
289  }
290  av_usleep(1000);
291  }
292  } else if (ret < 1)
293  return ret < 0 ? ret : len;
294  if (ret)
295  fast_retries = FFMAX(fast_retries, 2);
296  len += ret;
297  if (len < size && ff_check_interrupt(&h->interrupt_callback))
298  return AVERROR_EXIT;
299  }
300  return len;
301 }
302 
303 int ffurl_read(URLContext *h, unsigned char *buf, int size)
304 {
305  if (!(h->flags & AVIO_FLAG_READ))
306  return AVERROR(EIO);
307  return retry_transfer_wrapper(h, buf, size, 1, h->prot->url_read);
308 }
309 
310 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)
311 {
312  if (!(h->flags & AVIO_FLAG_READ))
313  return AVERROR(EIO);
314  return retry_transfer_wrapper(h, buf, size, size, h->prot->url_read);
315 }
316 
317 int ffurl_write(URLContext *h, const unsigned char *buf, int size)
318 {
319  if (!(h->flags & AVIO_FLAG_WRITE))
320  return AVERROR(EIO);
321  /* avoid sending too big packets */
322  if (h->max_packet_size && size > h->max_packet_size)
323  return AVERROR(EIO);
324 
325  return retry_transfer_wrapper(h, (unsigned char *)buf, size, size, (void*)h->prot->url_write);
326 }
327 
328 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
329 {
330  int64_t ret;
331 
332  if (!h->prot->url_seek)
333  return AVERROR(ENOSYS);
334  ret = h->prot->url_seek(h, pos, whence & ~AVSEEK_FORCE);
335  return ret;
336 }
337 
339 {
340  URLContext *h= *hh;
341  int ret = 0;
342  if (!h) return 0; /* can happen when ffurl_open fails */
343 
344  if (h->is_connected && h->prot->url_close)
345  ret = h->prot->url_close(h);
346 #if CONFIG_NETWORK
349 #endif
350  if (h->prot->priv_data_size) {
351  if (h->prot->priv_data_class)
353  av_freep(&h->priv_data);
354  }
355  av_freep(hh);
356  return ret;
357 }
358 
360 {
361  return ffurl_closep(&h);
362 }
363 
364 
365 int avio_check(const char *url, int flags)
366 {
367  URLContext *h;
368  int ret = ffurl_alloc(&h, url, flags, NULL);
369  if (ret)
370  return ret;
371 
372  if (h->prot->url_check) {
373  ret = h->prot->url_check(h, flags);
374  } else {
375  ret = ffurl_connect(h, NULL);
376  if (ret >= 0)
377  ret = flags;
378  }
379 
380  ffurl_close(h);
381  return ret;
382 }
383 
385 {
386  int64_t pos, size;
387 
388  size= ffurl_seek(h, 0, AVSEEK_SIZE);
389  if(size<0){
390  pos = ffurl_seek(h, 0, SEEK_CUR);
391  if ((size = ffurl_seek(h, -1, SEEK_END)) < 0)
392  return size;
393  size++;
394  ffurl_seek(h, pos, SEEK_SET);
395  }
396  return size;
397 }
398 
400 {
401  if (!h->prot->url_get_file_handle)
402  return -1;
403  return h->prot->url_get_file_handle(h);
404 }
405 
406 int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles)
407 {
408  if (!h->prot->url_get_multi_file_handle) {
409  if (!h->prot->url_get_file_handle)
410  return AVERROR(ENOSYS);
411  *handles = av_malloc(sizeof(**handles));
412  if (!*handles)
413  return AVERROR(ENOMEM);
414  *numhandles = 1;
415  *handles[0] = h->prot->url_get_file_handle(h);
416  return 0;
417  }
418  return h->prot->url_get_multi_file_handle(h, handles, numhandles);
419 }
420 
422 {
423  if (!h->prot->url_shutdown)
424  return AVERROR(EINVAL);
425  return h->prot->url_shutdown(h, flags);
426 }
427 
429 {
430  int ret;
431  if (cb && cb->callback && (ret = cb->callback(cb->opaque)))
432  return ret;
433  return 0;
434 }