1 /*****************************************************************************
2 * decomp.c : Decompression module for vlc
3 *****************************************************************************
4 * Copyright © 2008-2009 Rémi Denis-Courmont
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as published by
8 * the Free Software Foundation; either version 2.1 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
19 *****************************************************************************/
25 #include <vlc_common.h>
26 #include <vlc_plugin.h>
27 #include <vlc_stream.h>
28 #include <vlc_network.h>
33 # define _POSIX_SPAWN (-1)
36 #if (_POSIX_SPAWN >= 0)
40 #include <sys/ioctl.h>
41 #if defined (__linux__) && defined (HAVE_VMSPLICE)
43 # include <sys/mman.h>
48 static int OpenGzip (vlc_object_t *);
49 static int OpenBzip2 (vlc_object_t *);
50 static int OpenXZ (vlc_object_t *);
51 static void Close (vlc_object_t *);
54 set_description (N_("Decompression"))
55 set_category (CAT_INPUT)
56 set_subcategory (SUBCAT_INPUT_STREAM_FILTER)
57 set_capability ("stream_filter", 20)
58 set_callbacks (OpenXZ, Close)
61 set_callbacks (OpenBzip2, Close)
62 /* TODO: access shortnames for stream_UrlNew() */
65 set_callbacks (OpenGzip, Close)
74 int write_fd, read_fd;
77 static void cloexec (int fd)
79 int flags = fcntl (fd, F_GETFD);
80 fcntl (fd, F_SETFD, FD_CLOEXEC | ((flags != -1) ? flags : 0));
83 extern char **environ;
85 static const size_t bufsize = 65536;
87 static void cleanup_mmap (void *addr)
89 munmap (addr, bufsize);
93 static void *Thread (void *data)
95 stream_t *stream = data;
96 stream_sys_t *p_sys = stream->p_sys;
98 ssize_t page_mask = sysconf (_SC_PAGE_SIZE) - 1;
100 int fd = p_sys->write_fd;
106 int canc = vlc_savecancel ();
108 unsigned char *buf = mmap (NULL, bufsize, PROT_READ|PROT_WRITE,
109 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
110 vlc_cleanup_push (cleanup_mmap, buf);
112 unsigned char buf[bufsize];
115 len = stream_Read (stream->p_source, buf, bufsize);
116 vlc_restorecancel (canc);
119 for (ssize_t i = 0, j; i < len; i += j)
122 if ((len - i) <= page_mask) /* incomplete last page */
123 j = write (fd, buf + i, len - i);
126 struct iovec iov = { buf + i, (len - i) & ~page_mask, };
127 j = vmsplice (fd, &iov, 1, SPLICE_F_GIFT);
129 if (j == -1 && errno == ENOSYS) /* vmsplice() not supported */
131 j = write (fd, buf + i, len - i);
136 msg_Err (stream, "cannot write data (%m)");
142 vlc_cleanup_run (); /* munmap (buf, bufsize) */
147 msg_Dbg (stream, "compressed stream at EOF");
152 static int Peek (stream_t *, const uint8_t **, unsigned int);
154 #define MIN_BLOCK (1 << 10)
155 #define MAX_BLOCK (1 << 20)
157 * Reads decompressed from the decompression program
158 * @return -1 for EAGAIN, 0 for EOF, byte count otherwise.
160 static int Read (stream_t *stream, void *buf, unsigned int buflen)
162 stream_sys_t *p_sys = stream->p_sys;
166 if (buf == NULL) /* caller skips data, get big enough peek buffer */
167 buflen = Peek (stream, &(const uint8_t *){ NULL }, buflen);
169 if ((peeked = p_sys->peeked) != NULL)
170 { /* dequeue peeked data */
171 length = (buflen > peeked->i_buffer) ? peeked->i_buffer : buflen;
174 memcpy (buf, peeked->p_buffer, length);
175 buf = ((char *)buf) + length;
178 peeked->p_buffer += length;
179 peeked->i_buffer -= length;
180 if (peeked->i_buffer == 0)
182 block_Release (peeked);
183 p_sys->peeked = NULL;
185 p_sys->offset += length;
188 length += Read (stream, ((char *)buf) + length, buflen - length);
191 assert ((buf != NULL) || (buflen == 0));
193 length = net_Read (stream, p_sys->read_fd, NULL, buf, buflen, false);
196 p_sys->offset += length;
203 static int Peek (stream_t *stream, const uint8_t **pbuf, unsigned int len)
205 stream_sys_t *p_sys = stream->p_sys;
206 block_t *peeked = p_sys->peeked;
208 int fd = p_sys->read_fd;
211 peeked = block_Alloc (len);
212 else if ((curlen = peeked->i_buffer) < len)
213 peeked = block_Realloc (peeked, 0, len);
215 if ((p_sys->peeked = peeked) == NULL)
220 ssize_t val = net_Read (stream, fd, NULL, peeked->p_buffer + curlen,
225 peeked->i_buffer = curlen;
228 *pbuf = peeked->p_buffer;
235 static int Control (stream_t *stream, int query, va_list args)
237 stream_sys_t *p_sys = stream->p_sys;
241 case STREAM_CAN_SEEK:
242 case STREAM_CAN_FASTSEEK:
243 *(va_arg (args, bool *)) = false;
245 case STREAM_GET_POSITION:
246 *(va_arg (args, uint64_t *)) = p_sys->offset;
248 case STREAM_GET_SIZE:
249 *(va_arg (args, uint64_t *)) = 0;
258 * Pipe data through an external executable.
259 * @param stream the stream filter object.
260 * @param path path to the executable.
262 static int Open (stream_t *stream, const char *path)
264 stream_sys_t *p_sys = stream->p_sys = malloc (sizeof (*p_sys));
268 stream->pf_read = Read;
269 stream->pf_peek = Peek;
270 stream->pf_control = Control;
271 p_sys->peeked = NULL;
275 /* I am not a big fan of the pyramid style, but I cannot think of anything
276 * better here. There are too many failure cases. */
277 int ret = VLC_EGENERIC;
280 /* We use two pipes rather than one stream socket pair, so that we can
281 * use vmsplice() on Linux. */
282 if (pipe (comp) == 0)
285 p_sys->write_fd = comp[1];
288 if (pipe (uncomp) == 0)
291 p_sys->read_fd = uncomp[0];
293 #if (_POSIX_SPAWN >= 0)
294 posix_spawn_file_actions_t actions;
295 if (posix_spawn_file_actions_init (&actions) == 0)
297 char *const argv[] = { (char *)path, NULL };
299 if (!posix_spawn_file_actions_adddup2 (&actions, comp[0], 0)
300 && !posix_spawn_file_actions_addclose (&actions, comp[0])
301 && !posix_spawn_file_actions_adddup2 (&actions, uncomp[1], 1)
302 && !posix_spawn_file_actions_addclose (&actions, uncomp[1])
303 && !posix_spawnp (&p_sys->pid, path, &actions, NULL, argv,
306 if (vlc_clone (&p_sys->thread, Thread, stream,
307 VLC_THREAD_PRIORITY_INPUT) == 0)
312 msg_Err (stream, "Cannot execute %s", path);
315 posix_spawn_file_actions_destroy (&actions);
317 #else /* _POSIX_SPAWN */
318 switch (p_sys->pid = fork ())
321 msg_Err (stream, "Cannot fork (%m)");
328 execlp (path, path, (char *)NULL);
329 exit (1); /* if we get, execlp() failed! */
331 if (vlc_clone (&p_sys->thread, Thread, stream,
332 VLC_THREAD_PRIORITY_INPUT) == 0)
335 #endif /* _POSIX_SPAWN < 0 */
337 if (ret != VLC_SUCCESS)
341 if (ret != VLC_SUCCESS)
344 if (p_sys->pid != -1)
345 while (waitpid (p_sys->pid, &(int){ 0 }, 0) == -1);
353 * Releases allocate resources.
355 static void Close (vlc_object_t *obj)
357 stream_t *stream = (stream_t *)obj;
358 stream_sys_t *p_sys = stream->p_sys;
361 vlc_cancel (p_sys->thread);
362 close (p_sys->read_fd);
363 vlc_join (p_sys->thread, NULL);
364 close (p_sys->write_fd);
366 msg_Dbg (obj, "waiting for PID %u", (unsigned)p_sys->pid);
367 while (waitpid (p_sys->pid, &status, 0) == -1);
368 msg_Dbg (obj, "exit status %d", status);
371 block_Release (p_sys->peeked);
377 * Detects gzip file format
379 static int OpenGzip (vlc_object_t *obj)
381 stream_t *stream = (stream_t *)obj;
384 if (stream_Peek (stream->p_source, &peek, 3) < 3)
387 if (memcmp (peek, "\x1f\x8b\x08", 3))
390 msg_Dbg (obj, "detected gzip compressed stream");
391 return Open (stream, "zcat");
396 * Detects bzip2 file format
398 static int OpenBzip2 (vlc_object_t *obj)
400 stream_t *stream = (stream_t *)obj;
403 /* (Try to) parse the bzip2 header */
404 if (stream_Peek (stream->p_source, &peek, 10) < 10)
407 if (memcmp (peek, "BZh", 3) || (peek[3] < '1') || (peek[3] > '9')
408 || memcmp (peek + 4, "\x31\x41\x59\x26\x53\x59", 6))
411 msg_Dbg (obj, "detected bzip2 compressed stream");
412 return Open (stream, "bzcat");
416 * Detects xz file format
418 static int OpenXZ (vlc_object_t *obj)
420 stream_t *stream = (stream_t *)obj;
423 /* (Try to) parse the xz stream header */
424 if (stream_Peek (stream->p_source, &peek, 8) < 8)
427 if (memcmp (peek, "\xfd\x37\x7a\x58\x5a", 6))
430 msg_Dbg (obj, "detected xz compressed stream");
431 return Open (stream, "xzcat");