xwayland: Fix infinite loop at startup

Mutter recently added headless tests, and when running those tests the
Wayland compositor runs for a very short time.

Xwayland is spawned by the Wayland compositor and upon startup will
query the various Wayland protocol supported by the compositor.

To do so, it will do a roundtrip to the Wayland server waiting for
events it expects.

If the Wayland compositor terminates before Xwayland has got the replies
it expects, it will loop indefinitely calling `wl_display_roundtrip()`
continuously.

To avoid that issue, add a new `xwl_screen_roundtrip()` that checks for
the returned value from `wl_display_roundtrip()` and fails if it is
negative.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>

(cherry picked from commit 785e59060c)
This commit is contained in:
Olivier Fourdan 2020-04-24 17:45:49 +02:00 committed by Olivier Fourdan
parent b8b10e2930
commit 0430d13c1e
3 changed files with 18 additions and 14 deletions

View File

@ -2904,9 +2904,7 @@ InitInput(int argc, char *argv[])
xwl_screen->XYToWindow = pScreen->XYToWindow;
pScreen->XYToWindow = xwl_xy_to_window;
wl_display_roundtrip(xwl_screen->display);
while (xwl_screen->expecting_event)
wl_display_roundtrip(xwl_screen->display);
xwl_screen_roundtrip(xwl_screen);
}
void

View File

@ -1043,6 +1043,19 @@ xwl_sync_events (struct xwl_screen *xwl_screen)
xwl_read_events (xwl_screen);
}
void
xwl_screen_roundtrip(struct xwl_screen *xwl_screen)
{
int ret;
ret = wl_display_roundtrip(xwl_screen->display);
while (ret >= 0 && xwl_screen->expecting_event)
ret = wl_display_roundtrip(xwl_screen->display);
if (ret < 0)
xwl_give_up("could not connect to wayland server\n");
}
static CARD32
add_client_fd(OsTimerPtr timer, CARD32 time, void *arg)
{
@ -1182,14 +1195,7 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
xwl_screen->registry = wl_display_get_registry(xwl_screen->display);
wl_registry_add_listener(xwl_screen->registry,
&registry_listener, xwl_screen);
ret = wl_display_roundtrip(xwl_screen->display);
if (ret == -1) {
ErrorF("could not connect to wayland server\n");
return FALSE;
}
while (xwl_screen->expecting_event > 0)
wl_display_roundtrip(xwl_screen->display);
xwl_screen_roundtrip(xwl_screen);
bpc = xwl_screen->depth / 3;
green_bpc = xwl_screen->depth - 2 * bpc;
@ -1281,9 +1287,7 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
AddCallback(&PropertyStateCallback, xwl_property_callback, pScreen);
wl_display_roundtrip(xwl_screen->display);
while (xwl_screen->expecting_event)
wl_display_roundtrip(xwl_screen->display);
xwl_screen_roundtrip(xwl_screen);
return ret;
}

View File

@ -381,6 +381,8 @@ void xwl_window_create_frame_callback(struct xwl_window *xwl_window);
void xwl_sync_events (struct xwl_screen *xwl_screen);
void xwl_screen_roundtrip (struct xwl_screen *xwl_screen);
Bool xwl_screen_init_cursor(struct xwl_screen *xwl_screen);
struct xwl_screen *xwl_screen_get(ScreenPtr screen);