xwininfo: do not segfault on IO error

If the connection to the X server is lost while waiting for
the user to select a window interactively, xwininfo segfaults.

This is a regression introduced with the port to XCB, because
xcb_wait_for_event() can return NULL in case of an IO error and
xwininfo does not check for the actual returned value.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/dsimple.c b/dsimple.c
index 6432e13..ca746e9 100644
--- a/dsimple.c
+++ b/dsimple.c
@@ -205,6 +205,8 @@ xcb_window_t Select_Window(xcb_connection_t *dpy,
 	xcb_allow_events (dpy, XCB_ALLOW_SYNC_POINTER, XCB_TIME_CURRENT_TIME);
 	xcb_flush (dpy);
 	event = xcb_wait_for_event (dpy);
+	if (event == NULL)
+	    Fatal_Error ("Fatal IO error");
 	switch (event->response_type & 0x7f) {
 	case XCB_BUTTON_PRESS:
 	{