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decomp.c
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/*****************************************************************************
* decomp.c : Decompression module for vlc
*****************************************************************************
* Copyright © 2008-2009 Rémi Denis-Courmont
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_stream.h>
#include <vlc_network.h>
#include <vlc_fs.h>
#include <assert.h>
#include <unistd.h>
#include <errno.h>
#ifndef _POSIX_SPAWN
# define _POSIX_SPAWN (-1)
#endif
#include <fcntl.h>
#if (_POSIX_SPAWN >= 0)
# include <spawn.h>
#endif
#include <sys/wait.h>
#include <sys/ioctl.h>
#if defined (__linux__) && defined (HAVE_VMSPLICE)
# include <sys/uio.h>
# include <sys/mman.h>
#else
# undef HAVE_VMSPLICE
#endif
#include <vlc_interrupt.h>
#include <signal.h>
static int OpenGzip (vlc_object_t *);
static int OpenBzip2 (vlc_object_t *);
static int OpenXZ (vlc_object_t *);
static void Close (vlc_object_t *);
vlc_module_begin ()
set_category (CAT_INPUT)
set_subcategory (SUBCAT_INPUT_STREAM_FILTER)
set_capability ("stream_filter", 320)
set_description (N_("LZMA decompression"))
set_callbacks (OpenXZ, Close)
add_submodule ()
set_description (N_("Burrows-Wheeler decompression"))
set_callbacks (OpenBzip2, Close)
/* TODO: access shortnames for vlc_stream_NewURL() */
add_submodule ()
set_description (N_("gzip decompression"))
set_callbacks (OpenGzip, Close)
vlc_module_end ()
struct stream_sys_t
{
/* Thread data */
int write_fd;
/* Shared data */
vlc_cond_t wait;
vlc_mutex_t lock;
bool paused;
/* Caller data */
vlc_thread_t thread;
pid_t pid;
int read_fd;
bool can_pace;
bool can_pause;
int64_t pts_delay;
};
extern char **environ;
static const size_t bufsize = 65536;
#ifdef HAVE_VMSPLICE
static void cleanup_mmap (void *addr)
{
munmap (addr, bufsize);
}
#endif
static void *Thread (void *data)
{
stream_t *stream = data;
stream_sys_t *p_sys = stream->p_sys;
#ifdef HAVE_VMSPLICE
const ssize_t page_mask = sysconf (_SC_PAGE_SIZE) - 1;
#endif
int fd = p_sys->write_fd;
bool error = false;
sigset_t set;
sigemptyset(&set);
sigaddset(&set, SIGPIPE);
pthread_sigmask(SIG_BLOCK, &set, NULL);
do
{
ssize_t len;
int canc = vlc_savecancel ();
#ifdef HAVE_VMSPLICE
unsigned char *buf = mmap (NULL, bufsize, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (unlikely(buf == MAP_FAILED))
break;
vlc_cleanup_push (cleanup_mmap, buf);
#else
unsigned char *buf = malloc (bufsize);
if (unlikely(buf == NULL))
break;
vlc_cleanup_push (free, buf);
#endif
vlc_mutex_lock (&p_sys->lock);
while (p_sys->paused) /* practically always false, but... */
vlc_cond_wait (&p_sys->wait, &p_sys->lock);
len = vlc_stream_Read (stream->s, buf, bufsize);
vlc_mutex_unlock (&p_sys->lock);
vlc_restorecancel (canc);
error = len <= 0;
for (ssize_t i = 0, j; i < len; i += j)
{
#ifdef HAVE_VMSPLICE
if ((len - i) <= page_mask) /* incomplete last page */
j = write (fd, buf + i, len - i);
else
{
struct iovec iov = {
.iov_base = buf + i,
.iov_len = (len - i) & ~page_mask };
j = vmsplice (fd, &iov, 1, SPLICE_F_GIFT);
}
if (j == -1 && errno == ENOSYS) /* vmsplice() not supported */
#endif
j = write (fd, buf + i, len - i);
if (j <= 0)
{
if (j == 0)
errno = EPIPE;
msg_Err (stream, "cannot write data: %s",
vlc_strerror_c(errno));
error = true;
break;
}
}
vlc_cleanup_pop ();
#ifdef HAVE_VMSPLICE
munmap (buf, bufsize);
#else
free (buf);
#endif
}
while (!error);
msg_Dbg (stream, "compressed stream at EOF");
/* Let child process know about EOF */
p_sys->write_fd = -1;
vlc_close (fd);
return NULL;
}
#define MIN_BLOCK (1 << 10)
#define MAX_BLOCK (1 << 20)
/**
* Reads decompressed from the decompression program
* @return -1 for EAGAIN, 0 for EOF, byte count otherwise.
*/
static ssize_t Read (stream_t *stream, void *buf, size_t buflen)
{
stream_sys_t *sys = stream->p_sys;
ssize_t val = vlc_read_i11e (sys->read_fd, buf, buflen);
return (val >= 0) ? val : 0;
}
/**
*
*/
static int Control (stream_t *stream, int query, va_list args)
{
stream_sys_t *p_sys = stream->p_sys;
switch (query)
{
case STREAM_CAN_SEEK:
case STREAM_CAN_FASTSEEK:
*(va_arg (args, bool *)) = false;
break;
case STREAM_CAN_PAUSE:
*(va_arg (args, bool *)) = p_sys->can_pause;
break;
case STREAM_CAN_CONTROL_PACE:
*(va_arg (args, bool *)) = p_sys->can_pace;
break;
case STREAM_GET_SIZE:
*(va_arg (args, uint64_t *)) = 0;
break;
case STREAM_GET_PTS_DELAY:
*va_arg (args, int64_t *) = p_sys->pts_delay;
break;
case STREAM_SET_PAUSE_STATE:
{
bool paused = va_arg (args, unsigned);
vlc_mutex_lock (&p_sys->lock);
vlc_stream_Control(stream->s, STREAM_SET_PAUSE_STATE, paused);
p_sys->paused = paused;
vlc_cond_signal (&p_sys->wait);
vlc_mutex_unlock (&p_sys->lock);
break;
}
default:
return VLC_EGENERIC;
}
return VLC_SUCCESS;
}
/**
* Pipe data through an external executable.
* @param stream the stream filter object.
* @param path path to the executable.
*/
static int Open (stream_t *stream, const char *path)
{
stream_sys_t *p_sys = stream->p_sys = malloc (sizeof (*p_sys));
if (p_sys == NULL)
return VLC_ENOMEM;
vlc_cond_init (&p_sys->wait);
vlc_mutex_init (&p_sys->lock);
p_sys->paused = false;
p_sys->pid = -1;
vlc_stream_Control(stream->s, STREAM_CAN_PAUSE, &p_sys->can_pause);
vlc_stream_Control(stream->s, STREAM_CAN_CONTROL_PACE, &p_sys->can_pace);
vlc_stream_Control(stream->s, STREAM_GET_PTS_DELAY, &p_sys->pts_delay);
/* I am not a big fan of the pyramid style, but I cannot think of anything
* better here. There are too many failure cases. */
int ret = VLC_EGENERIC;
int comp[2];
/* We use two pipes rather than one stream socket pair, so that we can
* use vmsplice() on Linux. */
if (vlc_pipe (comp) == 0)
{
p_sys->write_fd = comp[1];
int uncomp[2];
if (vlc_pipe (uncomp) == 0)
{
p_sys->read_fd = uncomp[0];
#if (_POSIX_SPAWN >= 0)
posix_spawn_file_actions_t actions;
if (posix_spawn_file_actions_init (&actions) == 0)
{
char *const argv[] = { (char *)path, NULL };
if (!posix_spawn_file_actions_adddup2 (&actions, comp[0], 0)
&& !posix_spawn_file_actions_adddup2 (&actions, uncomp[1], 1)
&& !posix_spawnp (&p_sys->pid, path, &actions, NULL, argv,
environ))
{
if (vlc_clone (&p_sys->thread, Thread, stream,
VLC_THREAD_PRIORITY_INPUT) == 0)
ret = VLC_SUCCESS;
}
else
{
msg_Err (stream, "cannot execute %s", path);
p_sys->pid = -1;
}
posix_spawn_file_actions_destroy (&actions);
}
#else /* _POSIX_SPAWN */
switch (p_sys->pid = fork ())
{
case -1:
msg_Err (stream, "cannot fork: %s", vlc_strerror_c(errno));
break;
case 0:
dup2 (comp[0], 0);
dup2 (uncomp[1], 1);
execlp (path, path, (const char *)NULL);
exit (1); /* if we get, execlp() failed! */
default:
if (vlc_clone (&p_sys->thread, Thread, stream,
VLC_THREAD_PRIORITY_INPUT) == 0)
ret = VLC_SUCCESS;
}
#endif /* _POSIX_SPAWN < 0 */
vlc_close (uncomp[1]);
if (ret != VLC_SUCCESS)
vlc_close (uncomp[0]);
}
vlc_close (comp[0]);
if (ret != VLC_SUCCESS)
vlc_close (comp[1]);
}
if (ret != VLC_SUCCESS)
{
if (p_sys->pid != -1)
while (waitpid (p_sys->pid, &(int){ 0 }, 0) == -1);
vlc_mutex_destroy (&p_sys->lock);
vlc_cond_destroy (&p_sys->wait);
free (p_sys);
return ret;
}
stream->pf_read = Read;
stream->pf_seek = NULL;
stream->pf_control = Control;
return VLC_SUCCESS;
}
/**
* Releases allocate resources.
*/
static void Close (vlc_object_t *obj)
{
stream_t *stream = (stream_t *)obj;
stream_sys_t *p_sys = stream->p_sys;
int status;
vlc_cancel (p_sys->thread);
vlc_close (p_sys->read_fd);
vlc_join (p_sys->thread, NULL);
if (p_sys->write_fd != -1)
/* Killed before EOF? */
vlc_close (p_sys->write_fd);
msg_Dbg (obj, "waiting for PID %u", (unsigned)p_sys->pid);
while (waitpid (p_sys->pid, &status, 0) == -1);
msg_Dbg (obj, "exit status %d", status);
vlc_mutex_destroy (&p_sys->lock);
vlc_cond_destroy (&p_sys->wait);
free (p_sys);
}
/**
* Detects gzip file format
*/
static int OpenGzip (vlc_object_t *obj)
{
stream_t *stream = (stream_t *)obj;
const uint8_t *peek;
if (vlc_stream_Peek (stream->s, &peek, 3) < 3)
return VLC_EGENERIC;
if (memcmp (peek, "\x1f\x8b\x08", 3))
return VLC_EGENERIC;
msg_Dbg (obj, "detected gzip compressed stream");
return Open (stream, "zcat");
}
/**
* Detects bzip2 file format
*/
static int OpenBzip2 (vlc_object_t *obj)
{
stream_t *stream = (stream_t *)obj;
const uint8_t *peek;
/* (Try to) parse the bzip2 header */
if (vlc_stream_Peek (stream->s, &peek, 10) < 10)
return VLC_EGENERIC;
if (memcmp (peek, "BZh", 3) || (peek[3] < '1') || (peek[3] > '9')
|| memcmp (peek + 4, "\x31\x41\x59\x26\x53\x59", 6))
return VLC_EGENERIC;
msg_Dbg (obj, "detected bzip2 compressed stream");
return Open (stream, "bzcat");
}
/**
* Detects xz file format
*/
static int OpenXZ (vlc_object_t *obj)
{
stream_t *stream = (stream_t *)obj;
const uint8_t *peek;
/* (Try to) parse the xz stream header */
if (vlc_stream_Peek (stream->s, &peek, 8) < 8)
return VLC_EGENERIC;
if (memcmp (peek, "\xfd\x37\x7a\x58\x5a", 6))
return VLC_EGENERIC;
msg_Dbg (obj, "detected xz compressed stream");
return Open (stream, "xzcat");
}