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