[vlc-commits] live555: use timer for time-out prevention
Rémi Denis-Courmont
git at videolan.org
Sat Aug 6 22:35:22 CEST 2016
vlc | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Sat Aug 6 22:02:57 2016 +0300| [43c9253818309b02ccce3d4dabd98f79e90f4fa7] | committer: Rémi Denis-Courmont
live555: use timer for time-out prevention
This removes the data races on i_timeout, b_handle_keep_alive and
b_timeout_call.
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=43c9253818309b02ccce3d4dabd98f79e90f4fa7
---
modules/access/live555.cpp | 149 +++++++++++++++------------------------------
1 file changed, 50 insertions(+), 99 deletions(-)
diff --git a/modules/access/live555.cpp b/modules/access/live555.cpp
index bc5a9fa..d713570 100644
--- a/modules/access/live555.cpp
+++ b/modules/access/live555.cpp
@@ -173,13 +173,6 @@ typedef struct
} live_track_t;
-struct timeout_thread_t
-{
- demux_t *p_demux;
- vlc_thread_t handle;
- bool b_handle_keep_alive;
-};
-
class RTSPClientVlc;
struct demux_sys_t
@@ -209,9 +202,7 @@ struct demux_sys_t
double f_npt_start;
/* timeout thread information */
- int i_timeout; /* session timeout value in seconds */
- bool b_timeout_call;/* mark to send an RTSP call to prevent server timeout */
- timeout_thread_t *p_timeout; /* the actual thread that makes sure we don't timeout */
+ vlc_timer_t timer;
vlc_mutex_t timeout_mutex; /* Serialise calls to live555 in timeout thread w.r.t. Demux()/Control() */
/* */
@@ -265,7 +256,7 @@ static void StreamClose ( void * );
static void TaskInterruptData( void * );
static void TaskInterruptRTSP( void * );
-static void* TimeoutPrevention( void * );
+static void TimeoutPrevention( void * );
static unsigned char* parseH264ConfigStr( char const* configStr,
unsigned int& configSize );
@@ -303,6 +294,12 @@ static int Open ( vlc_object_t *p_this )
p_demux->p_sys = p_sys = (demux_sys_t*)calloc( 1, sizeof( demux_sys_t ) );
if( !p_sys ) return VLC_ENOMEM;
+ if( vlc_timer_create(&p_sys->timer, TimeoutPrevention, p_demux) )
+ {
+ free( p_sys );
+ return VLC_ENOMEM;
+ }
+
msg_Dbg( p_demux, "version " LIVEMEDIA_LIBRARY_VERSION_STRING );
TAB_INIT( p_sys->i_track, p_sys->track );
@@ -420,12 +417,7 @@ static void Close( vlc_object_t *p_this )
demux_t *p_demux = (demux_t*)p_this;
demux_sys_t *p_sys = p_demux->p_sys;
- if( p_sys->p_timeout )
- {
- vlc_cancel( p_sys->p_timeout->handle );
- vlc_join( p_sys->p_timeout->handle, NULL );
- free( p_sys->p_timeout );
- }
+ vlc_timer_destroy(p_sys->timer);
if( p_sys->rtsp && p_sys->ms ) p_sys->rtsp->sendTeardownCommand( *p_sys->ms, NULL );
if( p_sys->ms ) Medium::close( p_sys->ms );
@@ -1232,33 +1224,13 @@ static int Play( demux_t *p_demux )
}
/* Retrieve the timeout value and set up a timeout prevention thread */
- p_sys->i_timeout = p_sys->rtsp->sessionTimeoutParameter();
- if( p_sys->i_timeout <= 0 )
- p_sys->i_timeout = 60; /* default value from RFC2326 */
+ int timeout = p_sys->rtsp->sessionTimeoutParameter();
+ if( timeout <= 2 )
+ timeout = 60; /* default value from RFC2326 */
+ msg_Dbg( p_demux, "We have a timeout of %d seconds", timeout );
- /* start timeout-thread. GET_PARAMETER will be used if supported by
- * the server. OPTIONS will be used as a fallback */
- if( !p_sys->p_timeout )
- {
- msg_Dbg( p_demux, "We have a timeout of %d seconds", p_sys->i_timeout );
- p_sys->p_timeout = (timeout_thread_t *)malloc( sizeof(timeout_thread_t) );
- if( p_sys->p_timeout )
- {
- memset( p_sys->p_timeout, 0, sizeof(timeout_thread_t) );
- p_sys->p_timeout->p_demux = p_demux;
- if( vlc_clone( &p_sys->p_timeout->handle, TimeoutPrevention,
- p_sys->p_timeout, VLC_THREAD_PRIORITY_LOW ) )
- {
- msg_Err( p_demux, "cannot spawn liveMedia timeout thread" );
- free( p_sys->p_timeout );
- p_sys->p_timeout = NULL;
- }
- else
- msg_Dbg( p_demux, "spawned timeout thread" );
- }
- else
- msg_Err( p_demux, "cannot spawn liveMedia timeout thread" );
- }
+ mtime_t interval = (timeout - 2) * CLOCK_FREQ;
+ vlc_timer_schedule( p_sys->timer, false, interval, interval);
}
p_sys->i_pcr = VLC_TS_INVALID;
@@ -1287,20 +1259,6 @@ static int Demux( demux_t *p_demux )
during pause */
vlc_mutex_locker locker(&p_sys->timeout_mutex);
- /* Check if we need to send the server a Keep-A-Live signal */
- if( p_sys->b_timeout_call && p_sys->rtsp && p_sys->ms )
- {
- char *psz_bye = NULL;
- /* Use GET_PARAMETERS if supported. wmserver dialect supports
- * it, but does not report this properly. */
- if( p_sys->b_get_param || var_GetBool( p_demux, "rtsp-wmserver" ) )
- p_sys->rtsp->sendGetParameterCommand( *p_sys->ms, NULL, psz_bye );
- else
- p_sys->rtsp->sendOptionsCommand(NULL, NULL);
-
- p_sys->b_timeout_call = false;
- }
-
for( i = 0; i < p_sys->i_track; i++ )
{
live_track_t *tk = p_sys->track[i];
@@ -1649,19 +1607,6 @@ static int Control( demux_t *p_demux, int i_query, va_list args )
p_sys->f_seek_request = -1;
p_sys->b_paused = b_pause;
- /* When we Pause, we'll need the TimeoutPrevention thread to
- * handle sending the "Keep Alive" message to the server.
- * Unfortunately Live555 isn't thread safe and so can't
- * do this normally while the main Demux thread is handling
- * a live stream. We end up with the Timeout thread blocking
- * waiting for a response from the server. So when we PAUSE
- * we set a flag that the TimeoutPrevention function will check
- * and if it's set, it will trigger the GET_PARAMETER message */
- if( p_sys->b_paused && p_sys->p_timeout != NULL )
- p_sys->p_timeout->b_handle_keep_alive = true;
- else if( !p_sys->b_paused && p_sys->p_timeout != NULL )
- p_sys->p_timeout->b_handle_keep_alive = false;
-
if( !p_sys->b_paused )
{
for( int i = 0; i < p_sys->i_track; i++ )
@@ -1685,6 +1630,7 @@ static int Control( demux_t *p_demux, int i_query, va_list args )
p_sys->f_npt_length = p_sys->ms->playEndTime();
msg_Dbg( p_demux, "pause start: %f stop:%f", p_sys->f_npt_start, p_sys->f_npt_length );
+
return VLC_SUCCESS;
}
case DEMUX_GET_TITLE_INFO:
@@ -1716,6 +1662,7 @@ static int RollOverTcp( demux_t *p_demux )
var_SetBool( p_demux, "rtsp-tcp", true );
/* We close the old RTSP session */
+ vlc_timer_schedule(p_sys->timer, false, 0, 0);
p_sys->rtsp->sendTeardownCommand( *p_sys->ms, NULL );
Medium::close( p_sys->ms );
RTSPClient::close( p_sys->rtsp );
@@ -2118,41 +2065,45 @@ static void TaskInterruptData( void *p_private )
/*****************************************************************************
*
*****************************************************************************/
-VLC_NORETURN
-static void* TimeoutPrevention( void *p_data )
+static void TimeoutPrevention( void *p_data )
{
- timeout_thread_t *p_timeout = (timeout_thread_t *)p_data;
- demux_t *p_demux = p_timeout->p_demux;
+ demux_t *p_demux = (demux_t *) p_data;
demux_sys_t *p_sys = p_demux->p_sys;
+ char *bye = NULL;
- for( ;; )
- {
- /* Voodoo (= no) thread safety here! *Ahem* */
- if( p_timeout->b_handle_keep_alive )
- {
- /* Protect Live555 from us calling their functions simultaneously
- with Demux() or Control() */
- vlc_mutex_locker locker(&p_sys->timeout_mutex);
-
- char *psz_bye = NULL;
- int canc = vlc_savecancel ();
-
- p_sys->rtsp->sendGetParameterCommand( *p_sys->ms, default_live555_callback, psz_bye );
-
- if( !wait_Live555_response( p_demux ) )
- {
- msg_Err( p_demux, "GET_PARAMETER keepalive failed: %s",
- p_sys->env->getResultMsg() );
- /* Just continue, worst case is we get timed out later */
- }
+ /* Protect Live555 from us calling their functions simultaneously
+ with Demux() or Control() */
+ vlc_mutex_locker locker(&p_sys->timeout_mutex);
- vlc_restorecancel (canc);
- }
- p_sys->b_timeout_call = !p_timeout->b_handle_keep_alive;
+ /* If the timer fires while the demuxer owns the lock, and the demuxer
+ * then torns the session down, the pointers will become NULL. By the time
+ * this timer callback obtains the callback, either a new session was
+ * created and the timer is rescheduled, or the pointers are still NULL
+ * and the timer is descheduled. In the second case, bail out (then wait
+ * for the timer to be rescheduled or destroyed). In the first case, this
+ * might send an early refresh - that´s harmless but suboptimal (FIXME). */
+ if( p_sys->rtsp == NULL || p_sys->ms == NULL )
+ return;
+
+ bool use_get_param = p_sys->b_get_param;
+
+ /* Use GET_PARAMETERS if supported. wmserver dialect supports
+ * it, but does not report this properly. */
+ if( var_GetBool( p_demux, "rtsp-wmserver" ) )
+ use_get_param = true;
+
+ if( use_get_param )
+ p_sys->rtsp->sendGetParameterCommand( *p_sys->ms,
+ default_live555_callback, bye );
+ else
+ p_sys->rtsp->sendOptionsCommand( default_live555_callback, NULL );
- msleep (((int64_t)p_sys->i_timeout - 2) * CLOCK_FREQ);
+ if( !wait_Live555_response( p_demux ) )
+ {
+ msg_Err( p_demux, "keep-alive failed: %s",
+ p_sys->env->getResultMsg() );
+ /* Just continue, worst case is we get timed out later */
}
- vlc_assert_unreachable(); /* dead code */
}
/*****************************************************************************
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