Run startup command after xwayland is ready

include/wlr/xwayland.h

@@ -29,6 +29,7 @@ struct wlr_xwayland {
 	struct wlr_xwayland_cursor *cursor;
 
 	struct {
+		struct wl_signal ready;
 		struct wl_signal new_surface;
 	} events;
 

rootston/main.c

@@ -12,6 +12,18 @@
 
 struct roots_server server = { 0 };
 
+static void ready(struct wl_listener *listener, void *data) {
+	if (server.config->startup_cmd != NULL) {
+		const char *cmd = server.config->startup_cmd;
+		pid_t pid = fork();
+		if (pid < 0) {
+			wlr_log(L_ERROR, "cannot execute binding command: fork() failed");
+		} else if (pid == 0) {
+			execl("/bin/sh", "/bin/sh", "-c", cmd, (void *)NULL);
+		}
+	}
+}
+
 int main(int argc, char **argv) {
 	assert(server.config = roots_config_create_from_args(argc, argv));
 	assert(server.wl_display = wl_display_create());
@@ -43,17 +55,12 @@ int main(int argc, char **argv) {
 	}
 
 	setenv("WAYLAND_DISPLAY", socket, true);
-
-	if (server.config->startup_cmd != NULL) {
-		const char *cmd = server.config->startup_cmd;
-		pid_t pid = fork();
-		if (pid < 0) {
-			wlr_log(L_ERROR, "cannot execute binding command: fork() failed");
-			return 1;
-		} else if (pid == 0) {
-			execl("/bin/sh", "/bin/sh", "-c", cmd, (void *)NULL);
-		}
-	}
+#ifndef HAS_XWAYLAND
+	ready(NULL, NULL);
+#else
+	struct wl_listener xwayland_ready = { .notify = ready };
+	wl_signal_add(&server.desktop->xwayland->events.ready, &xwayland_ready);
+#endif
 
 	wl_display_run(server.wl_display);
 	wlr_backend_destroy(server.backend);

xwayland/xwayland.c

@@ -211,6 +211,8 @@ static int xserver_handle_ready(int signal_number, void *data) {
 	snprintf(display_name, sizeof(display_name), ":%d", wlr_xwayland->display);
 	setenv("DISPLAY", display_name, true);
 
+	wl_signal_emit(&wlr_xwayland->events.ready, wlr_xwayland);
+
 	return 1; /* wayland event loop dispatcher's count */
 }
 
@@ -223,6 +225,7 @@ static bool wlr_xwayland_init(struct wlr_xwayland *wlr_xwayland,
 	wlr_xwayland->wl_fd[0] = wlr_xwayland->wl_fd[1] = -1;
 	wlr_xwayland->wm_fd[0] = wlr_xwayland->wm_fd[1] = -1;
 	wl_signal_init(&wlr_xwayland->events.new_surface);
+	wl_signal_init(&wlr_xwayland->events.ready);
 
 	wlr_xwayland->display = open_display_sockets(wlr_xwayland->x_fd);
 	if (wlr_xwayland->display < 0) {