FFmpeg  4.3.9
file.c
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1 /*
2  * buffered file 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/internal.h"
24 #include "libavutil/opt.h"
25 #include "avformat.h"
26 #if HAVE_DIRENT_H
27 #include <dirent.h>
28 #endif
29 #include <fcntl.h>
30 #if HAVE_IO_H
31 #include <io.h>
32 #endif
33 #if HAVE_UNISTD_H
34 #include <unistd.h>
35 #endif
36 #include <sys/stat.h>
37 #include <stdlib.h>
38 #include "os_support.h"
39 #include "url.h"
40 
41 /* Some systems may not have S_ISFIFO */
42 #ifndef S_ISFIFO
43 # ifdef S_IFIFO
44 # define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
45 # else
46 # define S_ISFIFO(m) 0
47 # endif
48 #endif
49 
50 /* Not available in POSIX.1-1996 */
51 #ifndef S_ISLNK
52 # ifdef S_IFLNK
53 # define S_ISLNK(m) (((m) & S_IFLNK) == S_IFLNK)
54 # else
55 # define S_ISLNK(m) 0
56 # endif
57 #endif
58 
59 /* Not available in POSIX.1-1996 */
60 #ifndef S_ISSOCK
61 # ifdef S_IFSOCK
62 # define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
63 # else
64 # define S_ISSOCK(m) 0
65 # endif
66 #endif
67 
68 /* standard file protocol */
69 
70 typedef struct FileContext {
71  const AVClass *class;
72  int fd;
73  int trunc;
74  int blocksize;
75  int follow;
76  int seekable;
77 #if HAVE_DIRENT_H
78  DIR *dir;
79 #endif
80 } FileContext;
81 
82 static const AVOption file_options[] = {
83  { "truncate", "truncate existing files on write", offsetof(FileContext, trunc), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
84  { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
85  { "follow", "Follow a file as it is being written", offsetof(FileContext, follow), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM },
86  { "seekable", "Sets if the file is seekable", offsetof(FileContext, seekable), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 0, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_ENCODING_PARAM },
87  { NULL }
88 };
89 
90 static const AVOption pipe_options[] = {
91  { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
92  { NULL }
93 };
94 
95 static const AVClass file_class = {
96  .class_name = "file",
97  .item_name = av_default_item_name,
98  .option = file_options,
99  .version = LIBAVUTIL_VERSION_INT,
100 };
101 
102 static const AVClass pipe_class = {
103  .class_name = "pipe",
104  .item_name = av_default_item_name,
105  .option = pipe_options,
106  .version = LIBAVUTIL_VERSION_INT,
107 };
108 
109 static int file_read(URLContext *h, unsigned char *buf, int size)
110 {
111  FileContext *c = h->priv_data;
112  int ret;
113  size = FFMIN(size, c->blocksize);
114  ret = read(c->fd, buf, size);
115  if (ret == 0 && c->follow)
116  return AVERROR(EAGAIN);
117  if (ret == 0)
118  return AVERROR_EOF;
119  return (ret == -1) ? AVERROR(errno) : ret;
120 }
121 
122 static int file_write(URLContext *h, const unsigned char *buf, int size)
123 {
124  FileContext *c = h->priv_data;
125  int ret;
126  size = FFMIN(size, c->blocksize);
127  ret = write(c->fd, buf, size);
128  return (ret == -1) ? AVERROR(errno) : ret;
129 }
130 
132 {
133  FileContext *c = h->priv_data;
134  return c->fd;
135 }
136 
137 static int file_check(URLContext *h, int mask)
138 {
139  int ret = 0;
140  const char *filename = h->filename;
141  av_strstart(filename, "file:", &filename);
142 
143  {
144 #if HAVE_ACCESS && defined(R_OK)
145  if (access(filename, F_OK) < 0)
146  return AVERROR(errno);
147  if (mask&AVIO_FLAG_READ)
148  if (access(filename, R_OK) >= 0)
149  ret |= AVIO_FLAG_READ;
150  if (mask&AVIO_FLAG_WRITE)
151  if (access(filename, W_OK) >= 0)
152  ret |= AVIO_FLAG_WRITE;
153 #else
154  struct stat st;
155 # ifndef _WIN32
156  ret = stat(filename, &st);
157 # else
158  ret = win32_stat(filename, &st);
159 # endif
160  if (ret < 0)
161  return AVERROR(errno);
162 
163  ret |= st.st_mode&S_IRUSR ? mask&AVIO_FLAG_READ : 0;
164  ret |= st.st_mode&S_IWUSR ? mask&AVIO_FLAG_WRITE : 0;
165 #endif
166  }
167  return ret;
168 }
169 
171 {
172 #if HAVE_UNISTD_H
173  int ret;
174  const char *filename = h->filename;
175  av_strstart(filename, "file:", &filename);
176 
177  ret = rmdir(filename);
178  if (ret < 0 && (errno == ENOTDIR
179 # ifdef _WIN32
180  || errno == EINVAL
181 # endif
182  ))
183  ret = unlink(filename);
184  if (ret < 0)
185  return AVERROR(errno);
186 
187  return ret;
188 #else
189  return AVERROR(ENOSYS);
190 #endif /* HAVE_UNISTD_H */
191 }
192 
193 static int file_move(URLContext *h_src, URLContext *h_dst)
194 {
195  const char *filename_src = h_src->filename;
196  const char *filename_dst = h_dst->filename;
197  av_strstart(filename_src, "file:", &filename_src);
198  av_strstart(filename_dst, "file:", &filename_dst);
199 
200  if (rename(filename_src, filename_dst) < 0)
201  return AVERROR(errno);
202 
203  return 0;
204 }
205 
206 #if CONFIG_FILE_PROTOCOL
207 
208 static int file_open(URLContext *h, const char *filename, int flags)
209 {
210  FileContext *c = h->priv_data;
211  int access;
212  int fd;
213  struct stat st;
214 
215  av_strstart(filename, "file:", &filename);
216 
217  if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {
218  access = O_CREAT | O_RDWR;
219  if (c->trunc)
220  access |= O_TRUNC;
221  } else if (flags & AVIO_FLAG_WRITE) {
222  access = O_CREAT | O_WRONLY;
223  if (c->trunc)
224  access |= O_TRUNC;
225  } else {
226  access = O_RDONLY;
227  }
228 #ifdef O_BINARY
229  access |= O_BINARY;
230 #endif
231  fd = avpriv_open(filename, access, 0666);
232  if (fd == -1)
233  return AVERROR(errno);
234  c->fd = fd;
235 
236  h->is_streamed = !fstat(fd, &st) && S_ISFIFO(st.st_mode);
237 
238  /* Buffer writes more than the default 32k to improve throughput especially
239  * with networked file systems */
240  if (!h->is_streamed && flags & AVIO_FLAG_WRITE)
241  h->min_packet_size = h->max_packet_size = 262144;
242 
243  if (c->seekable >= 0)
244  h->is_streamed = !c->seekable;
245 
246  return 0;
247 }
248 
249 /* XXX: use llseek */
250 static int64_t file_seek(URLContext *h, int64_t pos, int whence)
251 {
252  FileContext *c = h->priv_data;
253  int64_t ret;
254 
255  if (whence == AVSEEK_SIZE) {
256  struct stat st;
257  ret = fstat(c->fd, &st);
258  return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size);
259  }
260 
261  ret = lseek(c->fd, pos, whence);
262 
263  return ret < 0 ? AVERROR(errno) : ret;
264 }
265 
266 static int file_close(URLContext *h)
267 {
268  FileContext *c = h->priv_data;
269  return close(c->fd);
270 }
271 
272 static int file_open_dir(URLContext *h)
273 {
274 #if HAVE_LSTAT
275  FileContext *c = h->priv_data;
276 
277  c->dir = opendir(h->filename);
278  if (!c->dir)
279  return AVERROR(errno);
280 
281  return 0;
282 #else
283  return AVERROR(ENOSYS);
284 #endif /* HAVE_LSTAT */
285 }
286 
287 static int file_read_dir(URLContext *h, AVIODirEntry **next)
288 {
289 #if HAVE_LSTAT
290  FileContext *c = h->priv_data;
291  struct dirent *dir;
292  char *fullpath = NULL;
293 
294  *next = ff_alloc_dir_entry();
295  if (!*next)
296  return AVERROR(ENOMEM);
297  do {
298  errno = 0;
299  dir = readdir(c->dir);
300  if (!dir) {
301  av_freep(next);
302  return AVERROR(errno);
303  }
304  } while (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."));
305 
306  fullpath = av_append_path_component(h->filename, dir->d_name);
307  if (fullpath) {
308  struct stat st;
309  if (!lstat(fullpath, &st)) {
310  if (S_ISDIR(st.st_mode))
311  (*next)->type = AVIO_ENTRY_DIRECTORY;
312  else if (S_ISFIFO(st.st_mode))
313  (*next)->type = AVIO_ENTRY_NAMED_PIPE;
314  else if (S_ISCHR(st.st_mode))
315  (*next)->type = AVIO_ENTRY_CHARACTER_DEVICE;
316  else if (S_ISBLK(st.st_mode))
317  (*next)->type = AVIO_ENTRY_BLOCK_DEVICE;
318  else if (S_ISLNK(st.st_mode))
319  (*next)->type = AVIO_ENTRY_SYMBOLIC_LINK;
320  else if (S_ISSOCK(st.st_mode))
321  (*next)->type = AVIO_ENTRY_SOCKET;
322  else if (S_ISREG(st.st_mode))
323  (*next)->type = AVIO_ENTRY_FILE;
324  else
325  (*next)->type = AVIO_ENTRY_UNKNOWN;
326 
327  (*next)->group_id = st.st_gid;
328  (*next)->user_id = st.st_uid;
329  (*next)->size = st.st_size;
330  (*next)->filemode = st.st_mode & 0777;
331  (*next)->modification_timestamp = INT64_C(1000000) * st.st_mtime;
332  (*next)->access_timestamp = INT64_C(1000000) * st.st_atime;
333  (*next)->status_change_timestamp = INT64_C(1000000) * st.st_ctime;
334  }
335  av_free(fullpath);
336  }
337 
338  (*next)->name = av_strdup(dir->d_name);
339  return 0;
340 #else
341  return AVERROR(ENOSYS);
342 #endif /* HAVE_LSTAT */
343 }
344 
345 static int file_close_dir(URLContext *h)
346 {
347 #if HAVE_LSTAT
348  FileContext *c = h->priv_data;
349  closedir(c->dir);
350  return 0;
351 #else
352  return AVERROR(ENOSYS);
353 #endif /* HAVE_LSTAT */
354 }
355 
357  .name = "file",
358  .url_open = file_open,
359  .url_read = file_read,
360  .url_write = file_write,
361  .url_seek = file_seek,
362  .url_close = file_close,
363  .url_get_file_handle = file_get_handle,
364  .url_check = file_check,
365  .url_delete = file_delete,
366  .url_move = file_move,
367  .priv_data_size = sizeof(FileContext),
368  .priv_data_class = &file_class,
369  .url_open_dir = file_open_dir,
370  .url_read_dir = file_read_dir,
371  .url_close_dir = file_close_dir,
372  .default_whitelist = "file,crypto,data"
373 };
374 
375 #endif /* CONFIG_FILE_PROTOCOL */
376 
377 #if CONFIG_PIPE_PROTOCOL
378 
379 static int pipe_open(URLContext *h, const char *filename, int flags)
380 {
381  FileContext *c = h->priv_data;
382  int fd;
383  char *final;
384  av_strstart(filename, "pipe:", &filename);
385 
386  fd = strtol(filename, &final, 10);
387  if((filename == final) || *final ) {/* No digits found, or something like 10ab */
388  if (flags & AVIO_FLAG_WRITE) {
389  fd = 1;
390  } else {
391  fd = 0;
392  }
393  }
394 #if HAVE_SETMODE
395  setmode(fd, O_BINARY);
396 #endif
397  c->fd = fd;
398  h->is_streamed = 1;
399  return 0;
400 }
401 
403  .name = "pipe",
404  .url_open = pipe_open,
405  .url_read = file_read,
406  .url_write = file_write,
407  .url_get_file_handle = file_get_handle,
408  .url_check = file_check,
409  .priv_data_size = sizeof(FileContext),
410  .priv_data_class = &pipe_class,
411  .default_whitelist = "crypto,data"
412 };
413 
414 #endif /* CONFIG_PIPE_PROTOCOL */
#define NULL
Definition: coverity.c:32
static int file_read(URLContext *h, unsigned char *buf, int size)
Definition: file.c:109
int size
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static const AVOption pipe_options[]
Definition: file.c:90
#define O_BINARY
int is_streamed
true if streamed (no seek possible), default = false
Definition: url.h:45
int seekable
Definition: file.c:76
Describes single entry of the directory.
Definition: avio.h:86
#define AVIO_FLAG_READ
read-only
Definition: avio.h:674
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:675
int follow
Definition: file.c:75
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
AVOptions.
miscellaneous OS support macros and functions.
int blocksize
Definition: file.c:74
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
#define AVERROR_EOF
End of file.
Definition: error.h:55
static int file_check(URLContext *h, int mask)
Definition: file.c:137
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:276
int trunc
Definition: file.c:73
static const uint16_t mask[17]
Definition: lzw.c:38
#define AVERROR(e)
Definition: error.h:43
static int file_delete(URLContext *h)
Definition: file.c:170
#define S_ISFIFO(m)
Definition: file.c:46
unsigned int pos
Definition: spdifenc.c:412
const URLProtocol ff_pipe_protocol
const URLProtocol ff_file_protocol
common internal API header
#define FFMIN(a, b)
Definition: common.h:96
static int file_move(URLContext *h_src, URLContext *h_dst)
Definition: file.c:193
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:253
long long int64_t
Definition: coverity.c:34
Definition: url.h:38
Describe the class of an AVClass context structure.
Definition: log.h:67
void * priv_data
Definition: url.h:41
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:277
static const AVClass file_class
Definition: file.c:95
static const AVOption file_options[]
Definition: file.c:82
const char * name
Definition: url.h:55
#define flags(name, subs,...)
Definition: cbs_av1.c:576
int fd
Definition: file.c:72
#define S_ISLNK(m)
Definition: file.c:55
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
Main libavformat public API header.
char * av_append_path_component(const char *path, const char *component)
Append path component to the existing path.
Definition: avstring.c:302
#define S_ISSOCK(m)
Definition: file.c:64
static int file_get_handle(URLContext *h)
Definition: file.c:131
static const AVClass pipe_class
Definition: file.c:102
static double c[64]
AVIODirEntry * ff_alloc_dir_entry(void)
Allocate directory entry with default values.
Definition: url.c:325
char * filename
specified URL
Definition: url.h:42
#define AVSEEK_SIZE
ORing this as the "whence" parameter to a seek function causes it to return the filesize without seek...
Definition: avio.h:531
#define av_free(p)
int max_packet_size
if non zero, the stream is packetized with this max packet size
Definition: url.h:44
#define av_freep(p)
unbuffered private I/O API
int min_packet_size
if non zero, the stream is packetized with this min packet size
Definition: url.h:51
static int file_write(URLContext *h, const unsigned char *buf, int size)
Definition: file.c:122