input/control: INPUT_CHANGE_BOOKMARK: fix leak and return

The previous implementation would potentially try to duplicate a
seekpoint that was never used due to invalid arguments, as well as
leaking said duplicate.

These changes make sure that we do not leak the resource, while also
preventing the unnecessary duplication + returning an error if
we are unable to complete the operation.

CID: 1409711
Signed-off-by: Thomas Guillem <thomas@gllm.fr>

src/input/control.c

@@ -222,22 +222,22 @@ int input_vaControl( input_thread_t *p_input, int i_query, va_list args )
             p_bkmk = va_arg( args, seekpoint_t * );
             i_bkmk = va_arg( args, int );
 
-            p_bkmk = vlc_seekpoint_Duplicate( p_bkmk );
-
-            if( !p_bkmk )
-                return VLC_EGENERIC;
-
             vlc_mutex_lock( &priv->p_item->lock );
             if( i_bkmk < priv->i_bookmark )
             {
-                vlc_seekpoint_Delete( priv->pp_bookmark[i_bkmk] );
-                priv->pp_bookmark[i_bkmk] = p_bkmk;
+                p_bkmk = vlc_seekpoint_Duplicate( p_bkmk );
+                if( p_bkmk )
+                {
+                    vlc_seekpoint_Delete( priv->pp_bookmark[i_bkmk] );
+                    priv->pp_bookmark[i_bkmk] = p_bkmk;
+                }
             }
+            else p_bkmk = NULL;
             vlc_mutex_unlock( &priv->p_item->lock );
 
             UpdateBookmarksOption( p_input );
 
-            return VLC_SUCCESS;
+            return p_bkmk ? VLC_SUCCESS : VLC_EGENERIC;
 
         case INPUT_DEL_BOOKMARK:
             i_bkmk = va_arg( args, int );