xwm: Check result of xcb_get_atom_name_reply

When printing debug information about atoms, the XWM would crash if the X
server failed to respond to a request about atom names. In practice this
occurred when the server itself crashed, e.g. when starting mplayer with the
"xv" vo.

diff --git a/src/xwayland/window-manager.c b/src/xwayland/window-manager.c
index e656eda..3fc5633 100644 (file)
--- a/src/xwayland/window-manager.c
+++ b/src/xwayland/window-manager.c
@@ -137,9 +137,15 @@ get_atom_name(xcb_connection_t *c, xcb_atom_t atom)
 
        cookie = xcb_get_atom_name (c, atom);
        reply = xcb_get_atom_name_reply (c, cookie, &e);
-       snprintf(buffer, sizeof buffer, "%.*s",
-                xcb_get_atom_name_name_length (reply),
-                xcb_get_atom_name_name (reply));
+
+       if(reply) {
+               snprintf(buffer, sizeof buffer, "%.*s",
+                        xcb_get_atom_name_name_length (reply),
+                        xcb_get_atom_name_name (reply));
+       } else {
+               snprintf(buffer, sizeof buffer, "(atom %u)", atom);
+       }
+
        free(reply);
 
        return buffer;