Fixed a race condition with input creation and events.

input_CreateThread* have been splitted in two functions:
 - input_Create
 - input_Start
to allow attaching to input events and creating settings/variables
before starting the input thread.

For consistency, input_StopThread has been renamed input_Stop.

Initial report from Hugo Beauzee-Luyssen.

include/vlc_input.h

@@ -248,14 +248,16 @@ static inline void vlc_input_attachment_Delete( input_attachment_t *a )
 #define INPUT_UPDATE_META       0x0040
 #define INPUT_UPDATE_SIGNAL     0x0080
 
-/** Get the input item for an input thread
- * FIXME see src/input/item.c but is is unsafe unless
- * you hold p_input
+/**
+ * This defines private core storage for an input.
  */
-VLC_EXPORT(input_item_t*, input_GetItem, (input_thread_t*));
-
 typedef struct input_thread_private_t input_thread_private_t;
 
+/**
+ * This defines an opaque input resource handler.
+ */
+typedef struct input_resource_t input_resource_t;
+
 /**
  * Main structure representing an input thread. This structure is mostly
  * private. The only public fields are READ-ONLY. You must use the helpers
@@ -431,32 +433,9 @@ typedef enum input_event_type_e
 
 } input_event_type_e;
 
-/** @}*/
-
-/*****************************************************************************
- * Prototypes
- *****************************************************************************/
-
 /**
- * It will create a new input thread.
- *
- * You must call input_StopThread() on it and then vlc_object_release().
+ * Input queries
  */
-#define input_CreateThread(a,b) __input_CreateThread(VLC_OBJECT(a),b)
-VLC_EXPORT( input_thread_t *, __input_CreateThread, ( vlc_object_t *, input_item_t * ) );
-
-/**
- * It will ask a input_thread_t to stop.
- *
- * b_abort must be true when a user stop is requested and not because you have
- * detected an error or an eof. It will be used to properly send the
- * INPUT_EVENT_ABORT event.
- */
-VLC_EXPORT( void,             input_StopThread,     ( input_thread_t *, bool b_abort ) );
-
-#define input_Read(a,b,c) __input_Read(VLC_OBJECT(a),b, c)
-VLC_EXPORT( int, __input_Read, ( vlc_object_t *, input_item_t *, bool ) );
-
 enum input_query_e
 {
     /* input variable "position" */
@@ -526,9 +505,37 @@ enum input_query_e
     INPUT_GET_VOUTS,        /* arg1=vout_thread_t ***, int *        res=can fail */
 };
 
+/** @}*/
+
+/*****************************************************************************
+ * Prototypes
+ *****************************************************************************/
+
+#define input_Create(a,b,c,d) __input_Create(VLC_OBJECT(a),b,c,d)
+VLC_EXPORT( input_thread_t *, __input_Create, ( vlc_object_t *p_parent, input_item_t *, const char *psz_log, input_resource_t * ) );
+
+#define input_CreateAndStart(a,b,c) __input_CreateAndStart(VLC_OBJECT(a),b,c)
+VLC_EXPORT( input_thread_t *, __input_CreateAndStart, ( vlc_object_t *p_parent, input_item_t *, const char *psz_log ) );
+
+VLC_EXPORT( int,  input_Start, ( input_thread_t * ) );
+
+VLC_EXPORT( void, input_Stop, ( input_thread_t *, bool b_abort ) );
+
+#define input_Read(a,b,c) __input_Read(VLC_OBJECT(a),b, c)
+VLC_EXPORT( int, __input_Read, ( vlc_object_t *, input_item_t *, bool ) );
+
 VLC_EXPORT( int, input_vaControl,( input_thread_t *, int i_query, va_list  ) );
+
 VLC_EXPORT( int, input_Control,  ( input_thread_t *, int i_query, ...  ) );
 
+/**
+ * Get the input item for an input thread
+ *
+ * You have to keep a reference to the input or to the input_item_t until
+ * you do not need it anymore.
+ */
+VLC_EXPORT( input_item_t*, input_GetItem, ( input_thread_t * ) );
+
 /**
  * It will return the current state of the input.
  * Provided for convenience.
@@ -567,7 +574,7 @@ static inline vout_thread_t *input_GetVout( input_thread_t *p_input )
          vlc_object_release( (vlc_object_t *)(pp_vout[i]) );
 
      p_vout = (i_vout >= 1) ? pp_vout[0] : NULL;
-     free (pp_vout);
+     free( pp_vout );
      return p_vout;
 }
 

modules/services_discovery/podcast.c

@@ -159,13 +159,16 @@ static void Close( vlc_object_t *p_this )
 
     for( i = 0; i < p_sys->i_input; i++ )
     {
-        if( p_sd->p_sys->pp_input[i] )
-        {
-            input_StopThread( p_sd->p_sys->pp_input[i], true );
-            vlc_object_release( p_sd->p_sys->pp_input[i] );
+        input_thread_t *p_input = p_sd->p_sys->pp_input[i];
+        if( !p_input )
+            continue;
+
+        input_Stop( p_input, true );
+        vlc_thread_join( p_input );
+        vlc_object_release( p_input );
+
         p_sd->p_sys->pp_input[i] = NULL;
     }
-    }
     free( p_sd->p_sys->pp_input );
     for( i = 0; i < p_sys->i_urls; i++ ) free( p_sys->ppsz_urls[i] );
     free( p_sys->ppsz_urls );
@@ -197,11 +200,14 @@ static void *Run( void *data )
 
         for( int i = 0; i < p_sd->p_sys->i_input; i++ )
         {
-            if( p_sd->p_sys->pp_input[i]->b_eof
-                || p_sd->p_sys->pp_input[i]->b_error )
+            input_thread_t *p_input = p_sd->p_sys->pp_input[i];
+
+            if( p_input->b_eof || p_input->b_error )
             {
-                input_StopThread( p_sd->p_sys->pp_input[i], false );
-                vlc_object_release( p_sd->p_sys->pp_input[i] );
+                input_Stop( p_input, false );
+                vlc_thread_join( p_input );
+                vlc_object_release( p_input );
+
                 p_sd->p_sys->pp_input[i] = NULL;
                 REMOVE_ELEM( p_sys->pp_input, p_sys->i_input, i );
                 i--;
@@ -253,7 +259,7 @@ static void ParseUrls( services_discovery_t *p_sd, char *psz_urls )
             services_discovery_AddItem( p_sd, p_input, NULL /* no cat */ );
             vlc_gc_decref( p_input );
             INSERT_ELEM( p_sys->pp_input, p_sys->i_input, p_sys->i_input,
-                         input_CreateThread( p_sd, p_input ) );
+                         input_CreateAndStart( p_sd, p_input, NULL ) );
         }
         if( psz_tok )  psz_urls = psz_tok+1;
         else           return;

src/control/media_player.c

@@ -89,7 +89,7 @@ static void release_input_thread( libvlc_media_player_t *p_mi, bool b_input_abor
                          input_event_changed, p_mi );
 
         /* We owned this one */
-        input_StopThread( p_input_thread, b_input_abort );
+        input_Stop( p_input_thread, b_input_abort );
         vlc_thread_join( p_input_thread );
 
         var_Destroy( p_input_thread, "drawable-hwnd" );
@@ -606,8 +606,8 @@ void libvlc_media_player_play( libvlc_media_player_t *p_mi,
         return;
     }
 
-    p_mi->p_input_thread = input_CreateThread(
-            p_mi->p_libvlc_instance->p_libvlc_int, p_mi->p_md->p_input_item );
+    p_mi->p_input_thread = input_Create( p_mi->p_libvlc_instance->p_libvlc_int,
+                                         p_mi->p_md->p_input_item, NULL, NULL );
 
     if( !p_mi->p_input_thread )
     {
@@ -643,6 +643,12 @@ void libvlc_media_player_play( libvlc_media_player_t *p_mi,
     var_AddCallback( p_input_thread, "can-pause", input_pausable_changed, p_mi );
     var_AddCallback( p_input_thread, "intf-event", input_event_changed, p_mi );
 
+    if( input_Start( p_input_thread ) )
+    {
+        vlc_object_release( p_input_thread );
+        p_mi->p_input_thread = NULL;
+    }
+
     vlc_mutex_unlock( &p_mi->object_lock );
 }
 
@@ -717,7 +723,7 @@ void libvlc_media_player_stop( libvlc_media_player_t *p_mi,
         if( !p_input_thread )
             return;
 
-        input_StopThread( p_input_thread, true );
+        input_Stop( p_input_thread, true );
         vlc_object_release( p_input_thread );
         p_mi->p_input_thread = NULL;
     }

src/input/input_interface.h

@@ -46,11 +46,6 @@ int input_Preparse( vlc_object_t *, input_item_t * );
  * FIXME it should NOT be defined here or not coded in misc/stats.c */
 input_stats_t *stats_NewInputStats( input_thread_t *p_input );
 
-/**
- * This defines an opaque input resource handler.
- */
-typedef struct input_resource_t input_resource_t;
-
 /**
  * This function releases an input_resource_t and all associated resources.
  */
@@ -74,8 +69,6 @@ void input_resource_TerminateVout( input_resource_t *p_resource );
 bool input_resource_HasVout( input_resource_t *p_resource );
 
 /* input.c */
-#define input_CreateThreadExtended(a,b,c,d) __input_CreateThreadExtended(VLC_OBJECT(a),b,c,d)
-input_thread_t *__input_CreateThreadExtended ( vlc_object_t *, input_item_t *, const char *, input_resource_t * );
 
 /**
  * This function detaches resources from a dead input.

src/input/vlm.c

@@ -531,12 +531,12 @@ static int vlm_OnMediaUpdate( vlm_t *p_vlm, vlm_media_sys_t *p_media )
             if( asprintf( &psz_header, _("Media: %s"), p_cfg->psz_name ) == -1 )
                 psz_header = NULL;
 
-            if( (p_input = input_CreateThreadExtended( p_vlm->p_libvlc, p_media->vod.p_item, psz_header, NULL ) ) )
+            if( (p_input = input_CreateAndStart( p_vlm->p_libvlc, p_media->vod.p_item, psz_header ) ) )
             {
                 while( !p_input->b_eof && !p_input->b_error )
                     msleep( 100000 );
 
-                input_StopThread( p_input, false );
+                input_Stop( p_input, false );
                 vlc_thread_join( p_input );
                 vlc_object_release( p_input );
             }
@@ -778,7 +778,7 @@ static void vlm_MediaInstanceDelete( vlm_t *p_vlm, int64_t id, vlm_media_instanc
     {
         input_resource_t *p_resource;
 
-        input_StopThread( p_input, true );
+        input_Stop( p_input, true );
         vlc_thread_join( p_input );
 
         p_resource = input_DetachResource( p_input );
@@ -861,7 +861,7 @@ static int vlm_ControlMediaInstanceStart( vlm_t *p_vlm, int64_t id, const char *
             return VLC_SUCCESS;
         }
 
-        input_StopThread( p_input, !p_input->b_eof && !p_input->b_error );
+        input_Stop( p_input, !p_input->b_eof && !p_input->b_error );
         vlc_thread_join( p_input );
 
         p_instance->p_input_resource = input_DetachResource( p_input );
@@ -881,8 +881,13 @@ static int vlm_ControlMediaInstanceStart( vlm_t *p_vlm, int64_t id, const char *
 
     if( asprintf( &psz_log, _("Media: %s"), p_media->cfg.psz_name ) != -1 )
     {
-        p_instance->p_input = input_CreateThreadExtended( p_vlm->p_libvlc, p_instance->p_item,
+        p_instance->p_input = input_Create( p_vlm->p_libvlc, p_instance->p_item,
                                             psz_log, p_instance->p_input_resource );
+        if( p_instance->p_input && input_Start( p_instance->p_input ) )
+        {
+            vlc_object_release( p_instance->p_input );
+            p_instance->p_input = NULL;
+        }
         p_instance->p_input_resource = NULL;
 
         if( !p_instance->p_input )

src/libvlccore.sym

@@ -169,8 +169,9 @@ image_Mime2Fourcc
 image_Type2Fourcc
 InitMD5
 input_Control
+__input_Create
+__input_CreateAndStart
 input_CreateFilename
-__input_CreateThread
 input_DecoderDecode
 input_DecoderDelete
 input_DecoderNew
@@ -199,7 +200,8 @@ input_item_SetURI
 input_MetaTypeToLocalizedString
 __input_Read
 input_SplitMRL
-input_StopThread
+input_Start
+input_Stop
 input_vaControl
 __intf_Create
 __intf_Eject

src/playlist/item.c

@@ -823,7 +823,7 @@ static void GoAndPreparse( playlist_t *p_playlist, int i_mode,
         pl_priv(p_playlist)->request.i_skip = 0;
         pl_priv(p_playlist)->request.p_item = p_toplay;
         if( pl_priv(p_playlist)->p_input )
-            input_StopThread( pl_priv(p_playlist)->p_input, true );
+            input_Stop( pl_priv(p_playlist)->p_input, true );
         pl_priv(p_playlist)->request.i_status = PLAYLIST_RUNNING;
         vlc_cond_signal( &pl_priv(p_playlist)->signal );
     }

src/playlist/thread.c

@@ -251,14 +251,17 @@ static int PlayItem( playlist_t *p_playlist, playlist_item_t *p_item )
 
     assert( p_sys->p_input == NULL );
 
-    input_thread_t *p_input_thread =
-        input_CreateThreadExtended( p_playlist, p_input, NULL, p_sys->p_input_resource );
-
+    input_thread_t *p_input_thread = input_Create( p_playlist, p_input, NULL, p_sys->p_input_resource );
     if( p_input_thread )
     {
         p_sys->p_input = p_input_thread;
-
         var_AddCallback( p_input_thread, "intf-event", InputEvent, p_playlist );
+
+        if( input_Start( p_sys->p_input ) )
+        {
+            vlc_object_release( p_input_thread );
+            p_sys->p_input = p_input_thread = NULL;
+        }
     }
 
     p_sys->p_input_resource = NULL;
@@ -473,7 +476,7 @@ static int LoopInput( playlist_t *p_playlist )
     if( ( p_sys->request.b_request || !vlc_object_alive( p_playlist ) ) && !p_input->b_die )
     {
         PL_DEBUG( "incoming request - stopping current input" );
-        input_StopThread( p_input, true );
+        input_Stop( p_input, true );
     }
 
     /* This input is dead. Remove it ! */
@@ -514,7 +517,7 @@ static int LoopInput( playlist_t *p_playlist )
     else if( p_input->b_error || p_input->b_eof )
     {
         PL_DEBUG( "finished input" );
-        input_StopThread( p_input, false );
+        input_Stop( p_input, false );
     }
     return VLC_SUCCESS;
 }