xwayland/selection: don't request another selection while one is pending
This will hopefully be fixed in the future by having separate windows
for each X11-to-Wayland transfer, but until then, let's avoid a
compositor crash.
@@ -150,6 +150,21 @@ static void source_send(struct wlr_xwm_selection *selection,
return;
}
+ // FIXME: we currently can't handle two X11-to-Wayland transfers at once due
+ // to reusing the same X11 window. Proceeding further here would lead us to
+ // lose track of the current `transfer->wl_client_fd` and use-after-free
+ // during cleanup. This doesn't happen often, but bail now to avoid a
+ // compositor crash later.
+ if (transfer->wl_client_fd > 0) {
+ wlr_log(WLR_ERROR, "source_send fd %d, but %d already in progress", fd,
+ transfer->wl_client_fd);
+ if (transfer->wl_client_fd != fd) {
+ close(fd);
+ }
+
+ return;
+ }
+
xcb_convert_selection(xwm->xcb_conn,
selection->window,
selection->atom,
