modules/stream_filter/decomp.c

   1 /*****************************************************************************
   2  * decomp.c : Decompression module for vlc
   3  *****************************************************************************
   4  * Copyright © 2008-2009 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * 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.
  10  *
  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 Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <vlc_common.h>
  26 #include <vlc_plugin.h>
  27 #include <vlc_stream.h>
  28 #include <vlc_network.h>
  29 #include <vlc_fs.h>
  30 #include <assert.h>
  31 #include <unistd.h>
  32 #include <errno.h>
  33 #ifndef _POSIX_SPAWN
  34 # define _POSIX_SPAWN (-1)
  35 #endif
  36 #include <fcntl.h>
  37 #if (_POSIX_SPAWN >= 0)
  38 # include <spawn.h>
  39 #endif
  40 #include <sys/wait.h>
  41 #include <sys/ioctl.h>
  42 #if defined (__linux__) && defined (HAVE_VMSPLICE)
  43 # include <sys/uio.h>
  44 # include <sys/mman.h>
  45 #else
  46 # undef HAVE_VMSPLICE
  47 #endif
  48 #include <vlc_interrupt.h>
  49
  50 #include <signal.h>
  51
  52 static int  OpenGzip (vlc_object_t *);
  53 static int  OpenBzip2 (vlc_object_t *);
  54 static int  OpenXZ (vlc_object_t *);
  55 static void Close (vlc_object_t *);
  56
  57 vlc_module_begin ()
  58     set_category (CAT_INPUT)
  59     set_subcategory (SUBCAT_INPUT_STREAM_FILTER)
  60     set_capability ("stream_filter", 20)
  61
  62     set_description (N_("LZMA decompression"))
  63     set_callbacks (OpenXZ, Close)
  64
  65     add_submodule ()
  66     set_description (N_("Burrows-Wheeler decompression"))
  67     set_callbacks (OpenBzip2, Close)
  68     /* TODO: access shortnames for vlc_stream_NewURL() */
  69
  70     add_submodule ()
  71     set_description (N_("gzip decompression"))
  72     set_callbacks (OpenGzip, Close)
  73 vlc_module_end ()
  74
  75 struct stream_sys_t
  76 {
  77     /* Thread data */
  78     int          write_fd;
  79
  80     /* Shared data */
  81     vlc_cond_t   wait;
  82     vlc_mutex_t  lock;
  83     bool         paused;
  84
  85     /* Caller data */
  86     vlc_thread_t thread;
  87     pid_t        pid;
  88
  89     int          read_fd;
  90     bool         can_pace;
  91     bool         can_pause;
  92     int64_t      pts_delay;
  93 };
  94
  95 extern char **environ;
  96
  97 static const size_t bufsize = 65536;
  98 #ifdef HAVE_VMSPLICE
  99 static void cleanup_mmap (void *addr)
 100 {
 101     munmap (addr, bufsize);
 102 }
 103 #endif
 104
 105 static void *Thread (void *data)
 106 {
 107     stream_t *stream = data;
 108     stream_sys_t *p_sys = stream->p_sys;
 109 #ifdef HAVE_VMSPLICE
 110     const ssize_t page_mask = sysconf (_SC_PAGE_SIZE) - 1;
 111 #endif
 112     int fd = p_sys->write_fd;
 113     bool error = false;
 114     sigset_t set;
 115
 116     sigemptyset(&set);
 117     sigaddset(&set, SIGPIPE);
 118     pthread_sigmask(SIG_BLOCK, &set, NULL);
 119
 120     do
 121     {
 122         ssize_t len;
 123         int canc = vlc_savecancel ();
 124 #ifdef HAVE_VMSPLICE
 125         unsigned char *buf = mmap (NULL, bufsize, PROT_READ|PROT_WRITE,
 126                                    MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
 127         if (unlikely(buf == MAP_FAILED))
 128             break;
 129         vlc_cleanup_push (cleanup_mmap, buf);
 130 #else
 131         unsigned char *buf = malloc (bufsize);
 132         if (unlikely(buf == NULL))
 133             break;
 134         vlc_cleanup_push (free, buf);
 135 #endif
 136
 137         vlc_mutex_lock (&p_sys->lock);
 138         while (p_sys->paused) /* practically always false, but... */
 139             vlc_cond_wait (&p_sys->wait, &p_sys->lock);
 140         len = vlc_stream_Read (stream->p_source, buf, bufsize);
 141         vlc_mutex_unlock (&p_sys->lock);
 142
 143         vlc_restorecancel (canc);
 144         error = len <= 0;
 145
 146         for (ssize_t i = 0, j; i < len; i += j)
 147         {
 148 #ifdef HAVE_VMSPLICE
 149             if ((len - i) <= page_mask) /* incomplete last page */
 150                 j = write (fd, buf + i, len - i);
 151             else
 152             {
 153                 struct iovec iov = {
 154                     .iov_base = buf + i,
 155                     .iov_len = (len - i) & ~page_mask };
 156
 157                 j = vmsplice (fd, &iov, 1, SPLICE_F_GIFT);
 158             }
 159             if (j == -1 && errno == ENOSYS) /* vmsplice() not supported */
 160 #endif
 161             j = write (fd, buf + i, len - i);
 162             if (j <= 0)
 163             {
 164                 if (j == 0)
 165                     errno = EPIPE;
 166                 msg_Err (stream, "cannot write data: %s",
 167                          vlc_strerror_c(errno));
 168                 error = true;
 169                 break;
 170             }
 171         }
 172         vlc_cleanup_pop ();
 173 #ifdef HAVE_VMSPLICE
 174         munmap (buf, bufsize);
 175 #else
 176         free (buf);
 177 #endif
 178     }
 179     while (!error);
 180
 181     msg_Dbg (stream, "compressed stream at EOF");
 182     /* Let child process know about EOF */
 183     p_sys->write_fd = -1;
 184     vlc_close (fd);
 185     return NULL;
 186 }
 187
 188
 189 #define MIN_BLOCK (1 << 10)
 190 #define MAX_BLOCK (1 << 20)
 191 /**
 192  * Reads decompressed from the decompression program
 193  * @return -1 for EAGAIN, 0 for EOF, byte count otherwise.
 194  */
 195 static ssize_t Read (stream_t *stream, void *buf, size_t buflen)
 196 {
 197     stream_sys_t *sys = stream->p_sys;
 198     ssize_t val = vlc_read_i11e (sys->read_fd, buf, buflen);
 199     return (val >= 0) ? val : 0;
 200 }
 201
 202 /**
 203  *
 204  */
 205 static int Control (stream_t *stream, int query, va_list args)
 206 {
 207     stream_sys_t *p_sys = stream->p_sys;
 208
 209     switch (query)
 210     {
 211         case STREAM_CAN_SEEK:
 212         case STREAM_CAN_FASTSEEK:
 213             *(va_arg (args, bool *)) = false;
 214             break;
 215         case STREAM_CAN_PAUSE:
 216              *(va_arg (args, bool *)) = p_sys->can_pause;
 217             break;
 218         case STREAM_CAN_CONTROL_PACE:
 219             *(va_arg (args, bool *)) = p_sys->can_pace;
 220             break;
 221         case STREAM_GET_SIZE:
 222             *(va_arg (args, uint64_t *)) = 0;
 223             break;
 224         case STREAM_GET_PTS_DELAY:
 225             *va_arg (args, int64_t *) = p_sys->pts_delay;
 226             break;
 227         case STREAM_SET_PAUSE_STATE:
 228         {
 229             bool paused = va_arg (args, unsigned);
 230
 231             vlc_mutex_lock (&p_sys->lock);
 232             vlc_stream_Control(stream->p_source, STREAM_SET_PAUSE_STATE,
 233                                paused);
 234             p_sys->paused = paused;
 235             vlc_cond_signal (&p_sys->wait);
 236             vlc_mutex_unlock (&p_sys->lock);
 237             break;
 238         }
 239         default:
 240             return VLC_EGENERIC;
 241     }
 242     return VLC_SUCCESS;
 243 }
 244
 245 /**
 246  * Pipe data through an external executable.
 247  * @param stream the stream filter object.
 248  * @param path path to the executable.
 249  */
 250 static int Open (stream_t *stream, const char *path)
 251 {
 252     stream_sys_t *p_sys = stream->p_sys = malloc (sizeof (*p_sys));
 253     if (p_sys == NULL)
 254         return VLC_ENOMEM;
 255
 256     vlc_cond_init (&p_sys->wait);
 257     vlc_mutex_init (&p_sys->lock);
 258     p_sys->paused = false;
 259     p_sys->pid = -1;
 260     vlc_stream_Control(stream->p_source, STREAM_CAN_PAUSE, &p_sys->can_pause);
 261     vlc_stream_Control(stream->p_source, STREAM_CAN_CONTROL_PACE,
 262                        &p_sys->can_pace);
 263     vlc_stream_Control(stream->p_source, STREAM_GET_PTS_DELAY,
 264                        &p_sys->pts_delay);
 265
 266     /* I am not a big fan of the pyramid style, but I cannot think of anything
 267      * better here. There are too many failure cases. */
 268     int ret = VLC_EGENERIC;
 269     int comp[2];
 270
 271     /* We use two pipes rather than one stream socket pair, so that we can
 272      * use vmsplice() on Linux. */
 273     if (vlc_pipe (comp) == 0)
 274     {
 275         p_sys->write_fd = comp[1];
 276
 277         int uncomp[2];
 278         if (vlc_pipe (uncomp) == 0)
 279         {
 280             p_sys->read_fd = uncomp[0];
 281
 282 #if (_POSIX_SPAWN >= 0)
 283             posix_spawn_file_actions_t actions;
 284             if (posix_spawn_file_actions_init (&actions) == 0)
 285             {
 286                 char *const argv[] = { (char *)path, NULL };
 287
 288                 if (!posix_spawn_file_actions_adddup2 (&actions, comp[0], 0)
 289                  && !posix_spawn_file_actions_adddup2 (&actions, uncomp[1], 1)
 290                  && !posix_spawnp (&p_sys->pid, path, &actions, NULL, argv,
 291                                    environ))
 292                 {
 293                     if (vlc_clone (&p_sys->thread, Thread, stream,
 294                                    VLC_THREAD_PRIORITY_INPUT) == 0)
 295                         ret = VLC_SUCCESS;
 296                 }
 297                 else
 298                 {
 299                     msg_Err (stream, "cannot execute %s", path);
 300                     p_sys->pid = -1;
 301                 }
 302                 posix_spawn_file_actions_destroy (&actions);
 303             }
 304 #else /* _POSIX_SPAWN */
 305             switch (p_sys->pid = fork ())
 306             {
 307                 case -1:
 308                     msg_Err (stream, "cannot fork: %s", vlc_strerror_c(errno));
 309                     break;
 310                 case 0:
 311                     dup2 (comp[0], 0);
 312                     dup2 (uncomp[1], 1);
 313                     execlp (path, path, (const char *)NULL);
 314                     exit (1); /* if we get, execlp() failed! */
 315                 default:
 316                     if (vlc_clone (&p_sys->thread, Thread, stream,
 317                                    VLC_THREAD_PRIORITY_INPUT) == 0)
 318                         ret = VLC_SUCCESS;
 319             }
 320 #endif /* _POSIX_SPAWN < 0 */
 321             vlc_close (uncomp[1]);
 322             if (ret != VLC_SUCCESS)
 323                 vlc_close (uncomp[0]);
 324         }
 325         vlc_close (comp[0]);
 326         if (ret != VLC_SUCCESS)
 327             vlc_close (comp[1]);
 328     }
 329
 330     if (ret != VLC_SUCCESS)
 331     {
 332         if (p_sys->pid != -1)
 333             while (waitpid (p_sys->pid, &(int){ 0 }, 0) == -1);
 334         vlc_mutex_destroy (&p_sys->lock);
 335         vlc_cond_destroy (&p_sys->wait);
 336         free (p_sys);
 337         return ret;
 338     }
 339
 340     stream->pf_read = Read;
 341     stream->pf_seek = NULL;
 342     stream->pf_control = Control;
 343     return VLC_SUCCESS;
 344 }
 345
 346
 347 /**
 348  * Releases allocate resources.
 349  */
 350 static void Close (vlc_object_t *obj)
 351 {
 352     stream_t *stream = (stream_t *)obj;
 353     stream_sys_t *p_sys = stream->p_sys;
 354     int status;
 355
 356     vlc_cancel (p_sys->thread);
 357     vlc_close (p_sys->read_fd);
 358     vlc_join (p_sys->thread, NULL);
 359     if (p_sys->write_fd != -1)
 360         /* Killed before EOF? */
 361         vlc_close (p_sys->write_fd);
 362
 363     msg_Dbg (obj, "waiting for PID %u", (unsigned)p_sys->pid);
 364     while (waitpid (p_sys->pid, &status, 0) == -1);
 365     msg_Dbg (obj, "exit status %d", status);
 366
 367     vlc_mutex_destroy (&p_sys->lock);
 368     vlc_cond_destroy (&p_sys->wait);
 369     free (p_sys);
 370 }
 371
 372
 373 /**
 374  * Detects gzip file format
 375  */
 376 static int OpenGzip (vlc_object_t *obj)
 377 {
 378     stream_t      *stream = (stream_t *)obj;
 379     const uint8_t *peek;
 380
 381     if (vlc_stream_Peek (stream->p_source, &peek, 3) < 3)
 382         return VLC_EGENERIC;
 383
 384     if (memcmp (peek, "\x1f\x8b\x08", 3))
 385         return VLC_EGENERIC;
 386
 387     msg_Dbg (obj, "detected gzip compressed stream");
 388     return Open (stream, "zcat");
 389 }
 390
 391
 392 /**
 393  * Detects bzip2 file format
 394  */
 395 static int OpenBzip2 (vlc_object_t *obj)
 396 {
 397     stream_t      *stream = (stream_t *)obj;
 398     const uint8_t *peek;
 399
 400     /* (Try to) parse the bzip2 header */
 401     if (vlc_stream_Peek (stream->p_source, &peek, 10) < 10)
 402         return VLC_EGENERIC;
 403
 404     if (memcmp (peek, "BZh", 3) || (peek[3] < '1') || (peek[3] > '9')
 405      || memcmp (peek + 4, "\x31\x41\x59\x26\x53\x59", 6))
 406         return VLC_EGENERIC;
 407
 408     msg_Dbg (obj, "detected bzip2 compressed stream");
 409     return Open (stream, "bzcat");
 410 }
 411
 412 /**
 413  * Detects xz file format
 414  */
 415 static int OpenXZ (vlc_object_t *obj)
 416 {
 417     stream_t      *stream = (stream_t *)obj;
 418     const uint8_t *peek;
 419
 420     /* (Try to) parse the xz stream header */
 421     if (vlc_stream_Peek (stream->p_source, &peek, 8) < 8)
 422         return VLC_EGENERIC;
 423
 424     if (memcmp (peek, "\xfd\x37\x7a\x58\x5a", 6))
 425         return VLC_EGENERIC;
 426
 427     msg_Dbg (obj, "detected xz compressed stream");
 428     return Open (stream, "xzcat");
 429 }