FFmpeg  4.0
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 #if HAVE_DIRENT_H
77  DIR *dir;
78 #endif
79 } FileContext;
80 
81 static const AVOption file_options[] = {
82  { "truncate", "truncate existing files on write", offsetof(FileContext, trunc), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
83  { "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 },
84  { "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 },
85  { NULL }
86 };
87 
88 static const AVOption pipe_options[] = {
89  { "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 },
90  { NULL }
91 };
92 
93 static const AVClass file_class = {
94  .class_name = "file",
95  .item_name = av_default_item_name,
96  .option = file_options,
97  .version = LIBAVUTIL_VERSION_INT,
98 };
99 
100 static const AVClass pipe_class = {
101  .class_name = "pipe",
102  .item_name = av_default_item_name,
103  .option = pipe_options,
104  .version = LIBAVUTIL_VERSION_INT,
105 };
106 
107 static int file_read(URLContext *h, unsigned char *buf, int size)
108 {
109  FileContext *c = h->priv_data;
110  int ret;
111  size = FFMIN(size, c->blocksize);
112  ret = read(c->fd, buf, size);
113  if (ret == 0 && c->follow)
114  return AVERROR(EAGAIN);
115  if (ret == 0)
116  return AVERROR_EOF;
117  return (ret == -1) ? AVERROR(errno) : ret;
118 }
119 
120 static int file_write(URLContext *h, const unsigned char *buf, int size)
121 {
122  FileContext *c = h->priv_data;
123  int ret;
124  size = FFMIN(size, c->blocksize);
125  ret = write(c->fd, buf, size);
126  return (ret == -1) ? AVERROR(errno) : ret;
127 }
128 
130 {
131  FileContext *c = h->priv_data;
132  return c->fd;
133 }
134 
135 static int file_check(URLContext *h, int mask)
136 {
137  int ret = 0;
138  const char *filename = h->filename;
139  av_strstart(filename, "file:", &filename);
140 
141  {
142 #if HAVE_ACCESS && defined(R_OK)
143  if (access(filename, F_OK) < 0)
144  return AVERROR(errno);
145  if (mask&AVIO_FLAG_READ)
146  if (access(filename, R_OK) >= 0)
147  ret |= AVIO_FLAG_READ;
148  if (mask&AVIO_FLAG_WRITE)
149  if (access(filename, W_OK) >= 0)
150  ret |= AVIO_FLAG_WRITE;
151 #else
152  struct stat st;
153 # ifndef _WIN32
154  ret = stat(filename, &st);
155 # else
156  ret = win32_stat(filename, &st);
157 # endif
158  if (ret < 0)
159  return AVERROR(errno);
160 
161  ret |= st.st_mode&S_IRUSR ? mask&AVIO_FLAG_READ : 0;
162  ret |= st.st_mode&S_IWUSR ? mask&AVIO_FLAG_WRITE : 0;
163 #endif
164  }
165  return ret;
166 }
167 
169 {
170 #if HAVE_UNISTD_H
171  int ret;
172  const char *filename = h->filename;
173  av_strstart(filename, "file:", &filename);
174 
175  ret = rmdir(filename);
176  if (ret < 0 && errno == ENOTDIR)
177  ret = unlink(filename);
178  if (ret < 0)
179  return AVERROR(errno);
180 
181  return ret;
182 #else
183  return AVERROR(ENOSYS);
184 #endif /* HAVE_UNISTD_H */
185 }
186 
187 static int file_move(URLContext *h_src, URLContext *h_dst)
188 {
189  const char *filename_src = h_src->filename;
190  const char *filename_dst = h_dst->filename;
191  av_strstart(filename_src, "file:", &filename_src);
192  av_strstart(filename_dst, "file:", &filename_dst);
193 
194  if (rename(filename_src, filename_dst) < 0)
195  return AVERROR(errno);
196 
197  return 0;
198 }
199 
200 #if CONFIG_FILE_PROTOCOL
201 
202 static int file_open(URLContext *h, const char *filename, int flags)
203 {
204  FileContext *c = h->priv_data;
205  int access;
206  int fd;
207  struct stat st;
208 
209  av_strstart(filename, "file:", &filename);
210 
211  if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {
212  access = O_CREAT | O_RDWR;
213  if (c->trunc)
214  access |= O_TRUNC;
215  } else if (flags & AVIO_FLAG_WRITE) {
216  access = O_CREAT | O_WRONLY;
217  if (c->trunc)
218  access |= O_TRUNC;
219  } else {
220  access = O_RDONLY;
221  }
222 #ifdef O_BINARY
223  access |= O_BINARY;
224 #endif
225  fd = avpriv_open(filename, access, 0666);
226  if (fd == -1)
227  return AVERROR(errno);
228  c->fd = fd;
229 
230  h->is_streamed = !fstat(fd, &st) && S_ISFIFO(st.st_mode);
231 
232  /* Buffer writes more than the default 32k to improve throughput especially
233  * with networked file systems */
234  if (!h->is_streamed && flags & AVIO_FLAG_WRITE)
235  h->min_packet_size = h->max_packet_size = 262144;
236 
237  return 0;
238 }
239 
240 /* XXX: use llseek */
241 static int64_t file_seek(URLContext *h, int64_t pos, int whence)
242 {
243  FileContext *c = h->priv_data;
244  int64_t ret;
245 
246  if (whence == AVSEEK_SIZE) {
247  struct stat st;
248  ret = fstat(c->fd, &st);
249  return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size);
250  }
251 
252  ret = lseek(c->fd, pos, whence);
253 
254  return ret < 0 ? AVERROR(errno) : ret;
255 }
256 
257 static int file_close(URLContext *h)
258 {
259  FileContext *c = h->priv_data;
260  return close(c->fd);
261 }
262 
263 static int file_open_dir(URLContext *h)
264 {
265 #if HAVE_LSTAT
266  FileContext *c = h->priv_data;
267 
268  c->dir = opendir(h->filename);
269  if (!c->dir)
270  return AVERROR(errno);
271 
272  return 0;
273 #else
274  return AVERROR(ENOSYS);
275 #endif /* HAVE_LSTAT */
276 }
277 
278 static int file_read_dir(URLContext *h, AVIODirEntry **next)
279 {
280 #if HAVE_LSTAT
281  FileContext *c = h->priv_data;
282  struct dirent *dir;
283  char *fullpath = NULL;
284 
285  *next = ff_alloc_dir_entry();
286  if (!*next)
287  return AVERROR(ENOMEM);
288  do {
289  errno = 0;
290  dir = readdir(c->dir);
291  if (!dir) {
292  av_freep(next);
293  return AVERROR(errno);
294  }
295  } while (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."));
296 
297  fullpath = av_append_path_component(h->filename, dir->d_name);
298  if (fullpath) {
299  struct stat st;
300  if (!lstat(fullpath, &st)) {
301  if (S_ISDIR(st.st_mode))
302  (*next)->type = AVIO_ENTRY_DIRECTORY;
303  else if (S_ISFIFO(st.st_mode))
304  (*next)->type = AVIO_ENTRY_NAMED_PIPE;
305  else if (S_ISCHR(st.st_mode))
306  (*next)->type = AVIO_ENTRY_CHARACTER_DEVICE;
307  else if (S_ISBLK(st.st_mode))
308  (*next)->type = AVIO_ENTRY_BLOCK_DEVICE;
309  else if (S_ISLNK(st.st_mode))
310  (*next)->type = AVIO_ENTRY_SYMBOLIC_LINK;
311  else if (S_ISSOCK(st.st_mode))
312  (*next)->type = AVIO_ENTRY_SOCKET;
313  else if (S_ISREG(st.st_mode))
314  (*next)->type = AVIO_ENTRY_FILE;
315  else
316  (*next)->type = AVIO_ENTRY_UNKNOWN;
317 
318  (*next)->group_id = st.st_gid;
319  (*next)->user_id = st.st_uid;
320  (*next)->size = st.st_size;
321  (*next)->filemode = st.st_mode & 0777;
322  (*next)->modification_timestamp = INT64_C(1000000) * st.st_mtime;
323  (*next)->access_timestamp = INT64_C(1000000) * st.st_atime;
324  (*next)->status_change_timestamp = INT64_C(1000000) * st.st_ctime;
325  }
326  av_free(fullpath);
327  }
328 
329  (*next)->name = av_strdup(dir->d_name);
330  return 0;
331 #else
332  return AVERROR(ENOSYS);
333 #endif /* HAVE_LSTAT */
334 }
335 
336 static int file_close_dir(URLContext *h)
337 {
338 #if HAVE_LSTAT
339  FileContext *c = h->priv_data;
340  closedir(c->dir);
341  return 0;
342 #else
343  return AVERROR(ENOSYS);
344 #endif /* HAVE_LSTAT */
345 }
346 
348  .name = "file",
349  .url_open = file_open,
350  .url_read = file_read,
351  .url_write = file_write,
352  .url_seek = file_seek,
353  .url_close = file_close,
354  .url_get_file_handle = file_get_handle,
355  .url_check = file_check,
356  .url_delete = file_delete,
357  .url_move = file_move,
358  .priv_data_size = sizeof(FileContext),
359  .priv_data_class = &file_class,
360  .url_open_dir = file_open_dir,
361  .url_read_dir = file_read_dir,
362  .url_close_dir = file_close_dir,
363  .default_whitelist = "file,crypto"
364 };
365 
366 #endif /* CONFIG_FILE_PROTOCOL */
367 
368 #if CONFIG_PIPE_PROTOCOL
369 
370 static int pipe_open(URLContext *h, const char *filename, int flags)
371 {
372  FileContext *c = h->priv_data;
373  int fd;
374  char *final;
375  av_strstart(filename, "pipe:", &filename);
376 
377  fd = strtol(filename, &final, 10);
378  if((filename == final) || *final ) {/* No digits found, or something like 10ab */
379  if (flags & AVIO_FLAG_WRITE) {
380  fd = 1;
381  } else {
382  fd = 0;
383  }
384  }
385 #if HAVE_SETMODE
386  setmode(fd, O_BINARY);
387 #endif
388  c->fd = fd;
389  h->is_streamed = 1;
390  return 0;
391 }
392 
394  .name = "pipe",
395  .url_open = pipe_open,
396  .url_read = file_read,
397  .url_write = file_write,
398  .url_get_file_handle = file_get_handle,
399  .url_check = file_check,
400  .priv_data_size = sizeof(FileContext),
401  .priv_data_class = &pipe_class,
402  .default_whitelist = "crypto"
403 };
404 
405 #endif /* CONFIG_PIPE_PROTOCOL */
#define NULL
Definition: coverity.c:32
static int file_read(URLContext *h, unsigned char *buf, int size)
Definition: file.c:107
int size
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static const AVOption pipe_options[]
Definition: file.c:88
#define O_BINARY
int is_streamed
true if streamed (no seek possible), default = false
Definition: url.h:45
Describes single entry of the directory.
Definition: avio.h:86
#define AVIO_FLAG_READ
read-only
Definition: avio.h:654
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
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
static int flags
Definition: log.c:55
#define AVERROR_EOF
End of file.
Definition: error.h:55
static int file_check(URLContext *h, int mask)
Definition: file.c:135
#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:168
#define S_ISFIFO(m)
Definition: file.c:46
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:187
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
void * buf
Definition: avisynth_c.h:690
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:93
static const AVOption file_options[]
Definition: file.c:81
const char * name
Definition: url.h:55
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:295
#define S_ISSOCK(m)
Definition: file.c:64
static int file_get_handle(URLContext *h)
Definition: file.c:129
static const AVClass pipe_class
Definition: file.c:100
static double c[64]
AVIODirEntry * ff_alloc_dir_entry(void)
Allocate directory entry with default values.
Definition: url.c:149
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:120