Fix a memory leak.

Test for the right thing before tring to do anything.
Check malloc return value (fix potential segfault).

src/input/control.c

@@ -611,6 +611,8 @@ static void UpdateBookmarksOption( input_thread_t *p_input )
     char *psz_value = NULL, *psz_next = NULL;
 
     vlc_mutex_lock( &p_input->p->input.p_item->lock );
+    if( p_input->p->i_bookmark > 0 )
+    {
         for( i = 0; i < p_input->p->i_bookmark; i++ )
         {
             i_len += snprintf( NULL, 0, "{name=%s,bytes=%"PRId64",time=%"PRId64"}",
@@ -618,10 +620,10 @@ static void UpdateBookmarksOption( input_thread_t *p_input )
                                p_input->p->bookmark[i]->i_byte_offset,
                                p_input->p->bookmark[i]->i_time_offset/1000000 );
         }
+        psz_value = psz_next = malloc( i_len + p_input->p->i_bookmark );
+
         for( i = 0; i < p_input->p->i_bookmark; i++ )
         {
-        if( !i ) psz_value = psz_next = malloc( i_len + p_input->p->i_bookmark );
-
             sprintf( psz_next, "{name=%s,bytes=%"PRId64",time=%"PRId64"}",
                      p_input->p->bookmark[i]->psz_name,
                      p_input->p->bookmark[i]->i_byte_offset,
@@ -629,7 +631,6 @@ static void UpdateBookmarksOption( input_thread_t *p_input )
 
             psz_next += strlen( psz_next );
             if( i < p_input->p->i_bookmark - 1)
-        {
                 *psz_next = ','; psz_next++;
         }
     }
@@ -637,4 +638,6 @@ static void UpdateBookmarksOption( input_thread_t *p_input )
 
     input_Control( p_input, INPUT_ADD_OPTION, "bookmarks",
                    psz_value ? psz_value : "" );
+    free( psz_value );
 }
+