xwayland: split server

Split the server part of wlr_xwayland into wlr_xwayland_server. This
allows compositors to implement their own XWM when wlroots' isn't a good
fit.

1 files changed, 54 insertions, 388 deletions

diff --git a/xwayland/xwayland.c b/xwayland/xwayland.c
index 77698f44..ae86d541 100644
--- a/xwayland/xwayland.c
+++ b/xwayland/xwayland.c
@@ -26,437 +26,103 @@ struct wlr_xwayland_cursor {
 	int32_t hotspot_y;
 };
 
-static void safe_close(int fd) {
-	if (fd >= 0) {
-		close(fd);
-	}
-}
-
-static int fill_arg(char ***argv, const char *fmt, ...) {
-	int len;
-	char **cur_arg = *argv;
-	va_list args;
-	va_start(args, fmt);
-	len = vsnprintf(NULL, 0, fmt, args) + 1;
-	va_end(args);
-	while (*cur_arg) {
-		cur_arg++;
-	}
-	*cur_arg = malloc(len);
-	if (!*cur_arg) {
-		return -1;
-	}
-	*argv = cur_arg;
-	va_start(args, fmt);
-	len = vsnprintf(*cur_arg, len, fmt, args);
-	va_end(args);
-	return len;
-}
-
-_Noreturn static void exec_xwayland(struct wlr_xwayland *wlr_xwayland) {
-	if (!set_cloexec(wlr_xwayland->x_fd[0], false) ||
-			!set_cloexec(wlr_xwayland->x_fd[1], false) ||
-			!set_cloexec(wlr_xwayland->wm_fd[1], false) ||
-			!set_cloexec(wlr_xwayland->wl_fd[1], false)) {
-		_exit(EXIT_FAILURE);
-	}
-
-	/* Make Xwayland signal us when it's ready */
-	signal(SIGUSR1, SIG_IGN);
-
-	char *argv[] = {
-		"Xwayland", NULL /* display, e.g. :1 */,
-		"-rootless", "-terminate",
-		"-listen", NULL /* x_fd[0] */,
-		"-listen", NULL /* x_fd[1] */,
-		"-wm", NULL /* wm_fd[1] */,
-		NULL,
-	};
-	char **cur_arg = argv;
-
-	if (fill_arg(&cur_arg, ":%d", wlr_xwayland->display) < 0 ||
-			fill_arg(&cur_arg, "%d", wlr_xwayland->x_fd[0]) < 0 ||
-			fill_arg(&cur_arg, "%d", wlr_xwayland->x_fd[1]) < 0 ||
-			fill_arg(&cur_arg, "%d", wlr_xwayland->wm_fd[1]) < 0) {
-		wlr_log_errno(WLR_ERROR, "alloc/print failure");
-		_exit(EXIT_FAILURE);
-	}
-
-	char wayland_socket_str[16];
-	snprintf(wayland_socket_str, sizeof(wayland_socket_str), "%d", wlr_xwayland->wl_fd[1]);
-	setenv("WAYLAND_SOCKET", wayland_socket_str, true);
-
-	wlr_log(WLR_INFO, "WAYLAND_SOCKET=%d Xwayland :%d -rootless -terminate -listen %d -listen %d -wm %d",
-		wlr_xwayland->wl_fd[1], wlr_xwayland->display, wlr_xwayland->x_fd[0],
-		wlr_xwayland->x_fd[1], wlr_xwayland->wm_fd[1]);
-
-	// Closes stdout/stderr depending on log verbosity
-	enum wlr_log_importance verbosity = wlr_log_get_verbosity();
-	int devnull = open("/dev/null", O_WRONLY | O_CREAT | O_CLOEXEC, 0666);
-	if (devnull < 0) {
-		wlr_log_errno(WLR_ERROR, "XWayland: failed to open /dev/null");
-		_exit(EXIT_FAILURE);
-	}
-	if (verbosity < WLR_INFO) {
-		dup2(devnull, STDOUT_FILENO);
-	}
-	if (verbosity < WLR_ERROR) {
-		dup2(devnull, STDERR_FILENO);
-	}
-
-	// This returns if and only if the call fails
-	execvp("Xwayland", argv);
-
-	wlr_log_errno(WLR_ERROR, "failed to exec Xwayland");
-	close(devnull);
-	_exit(EXIT_FAILURE);
-}
-
-static void xwayland_finish_server(struct wlr_xwayland *wlr_xwayland) {
-	if (!wlr_xwayland || wlr_xwayland->display == -1) {
-		return;
-	}
-
-	if (wlr_xwayland->x_fd_read_event[0]) {
-		wl_event_source_remove(wlr_xwayland->x_fd_read_event[0]);
-		wl_event_source_remove(wlr_xwayland->x_fd_read_event[1]);
-
-		wlr_xwayland->x_fd_read_event[0] = wlr_xwayland->x_fd_read_event[1] = NULL;
-	}
-
-	if (wlr_xwayland->cursor != NULL) {
-		free(wlr_xwayland->cursor);
-	}
-
-	xwm_destroy(wlr_xwayland->xwm);
-
-	if (wlr_xwayland->client) {
-		wl_list_remove(&wlr_xwayland->client_destroy.link);
-		wl_client_destroy(wlr_xwayland->client);
-	}
-	if (wlr_xwayland->sigusr1_source) {
-		wl_event_source_remove(wlr_xwayland->sigusr1_source);
-	}
-
-	safe_close(wlr_xwayland->wl_fd[0]);
-	safe_close(wlr_xwayland->wl_fd[1]);
-	safe_close(wlr_xwayland->wm_fd[0]);
-	safe_close(wlr_xwayland->wm_fd[1]);
-	memset(wlr_xwayland, 0, offsetof(struct wlr_xwayland, display));
-	wlr_xwayland->wl_fd[0] = wlr_xwayland->wl_fd[1] = -1;
-	wlr_xwayland->wm_fd[0] = wlr_xwayland->wm_fd[1] = -1;
-
-	/* We do not kill the Xwayland process, it dies to broken pipe
-	 * after we close our side of the wm/wl fds. This is more reliable
-	 * than trying to kill something that might no longer be Xwayland.
-	 */
-}
-
-static void xwayland_finish_display(struct wlr_xwayland *wlr_xwayland) {
-	if (!wlr_xwayland || wlr_xwayland->display == -1) {
-		return;
-	}
-
-	safe_close(wlr_xwayland->x_fd[0]);
-	safe_close(wlr_xwayland->x_fd[1]);
-	wlr_xwayland->x_fd[0] = wlr_xwayland->x_fd[1] = -1;
-
-	wl_list_remove(&wlr_xwayland->display_destroy.link);
-
-	unlink_display_sockets(wlr_xwayland->display);
-	wlr_xwayland->display = -1;
-	wlr_xwayland->display_name[0] = '\0';
+static void handle_server_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_xwayland *xwayland =
+		wl_container_of(listener, xwayland, server_destroy);
+	wlr_xwayland_destroy(xwayland);
 }
 
-static bool xwayland_start_server(struct wlr_xwayland *wlr_xwayland);
-static bool xwayland_start_server_lazy(struct wlr_xwayland *wlr_xwayland);
-
-static void handle_client_destroy(struct wl_listener *listener, void *data) {
-	struct wlr_xwayland *wlr_xwayland =
-		wl_container_of(listener, wlr_xwayland, client_destroy);
+static void handle_server_ready(struct wl_listener *listener, void *data) {
+	struct wlr_xwayland *xwayland =
+		wl_container_of(listener, xwayland, server_ready);
+	struct wlr_xwayland_server_ready_event *event = data;
 
-	if (wlr_xwayland->sigusr1_source) {
-		// Xwayland failed to start, let the sigusr1 handler deal with it
+	xwayland->xwm = xwm_create(xwayland, event->wm_fd);
+	if (!xwayland->xwm) {
 		return;
 	}
 
-	// Don't call client destroy: it's being destroyed already
-	wlr_xwayland->client = NULL;
-	wl_list_remove(&wlr_xwayland->client_destroy.link);
-
-	xwayland_finish_server(wlr_xwayland);
-
-	if (time(NULL) - wlr_xwayland->server_start > 5) {
-		if (wlr_xwayland->lazy) {
-			wlr_log(WLR_INFO, "Restarting Xwayland (lazy)");
-			xwayland_start_server_lazy(wlr_xwayland);
-		} else  {
-			wlr_log(WLR_INFO, "Restarting Xwayland");
-			xwayland_start_server(wlr_xwayland);
-		}
-	}
-}
-
-static void handle_display_destroy(struct wl_listener *listener, void *data) {
-	struct wlr_xwayland *wlr_xwayland =
-		wl_container_of(listener, wlr_xwayland, display_destroy);
-
-	// Don't call client destroy: the display is being destroyed, it's too late
-	if (wlr_xwayland->client) {
-		wlr_xwayland->client = NULL;
-		wl_list_remove(&wlr_xwayland->client_destroy.link);
-	}
-
-	wlr_xwayland_destroy(wlr_xwayland);
-}
-
-static int xserver_handle_ready(int signal_number, void *data) {
-	struct wlr_xwayland *wlr_xwayland = data;
-
-	int stat_val = -1;
-	while (waitpid(wlr_xwayland->pid, &stat_val, 0) < 0) {
-		if (errno == EINTR) {
-			continue;
-		}
-		wlr_log_errno(WLR_ERROR, "waitpid for Xwayland fork failed");
-		goto error;
-	}
-	if (stat_val) {
-		wlr_log(WLR_ERROR, "Xwayland startup failed, not setting up xwm");
-		goto error;
-	}
-	wlr_log(WLR_DEBUG, "Xserver is ready");
-
-	wlr_xwayland->xwm = xwm_create(wlr_xwayland);
-	if (!wlr_xwayland->xwm) {
-		goto error;
-	}
-
-	if (wlr_xwayland->seat) {
-		xwm_set_seat(wlr_xwayland->xwm, wlr_xwayland->seat);
+	if (xwayland->seat) {
+		xwm_set_seat(xwayland->xwm, xwayland->seat);
 	}
 
-	wl_event_source_remove(wlr_xwayland->sigusr1_source);
-	wlr_xwayland->sigusr1_source = NULL;
-
-	if (wlr_xwayland->cursor != NULL) {
-		struct wlr_xwayland_cursor *cur = wlr_xwayland->cursor;
-		xwm_set_cursor(wlr_xwayland->xwm, cur->pixels, cur->stride, cur->width,
+	if (xwayland->cursor != NULL) {
+		struct wlr_xwayland_cursor *cur = xwayland->cursor;
+		xwm_set_cursor(xwayland->xwm, cur->pixels, cur->stride, cur->width,
 			cur->height, cur->hotspot_x, cur->hotspot_y);
 		free(cur);
-		wlr_xwayland->cursor = NULL;
+		xwayland->cursor = NULL;
 	}
 
-
-	wlr_signal_emit_safe(&wlr_xwayland->events.ready, wlr_xwayland);
+	wlr_signal_emit_safe(&xwayland->events.ready, NULL);
 	/* ready is a one-shot signal, fire and forget */
-	wl_signal_init(&wlr_xwayland->events.ready);
-
-	return 1; /* wayland event loop dispatcher's count */
-error:
-	/* clean up */
-	wlr_xwayland_set_seat(wlr_xwayland, NULL);
-	xwayland_finish_server(wlr_xwayland);
-	xwayland_finish_display(wlr_xwayland);
-
-	return 1;
-}
-
-static int xwayland_socket_connected(int fd, uint32_t mask, void* data){
-	struct wlr_xwayland *wlr_xwayland = data;
-
-	wl_event_source_remove(wlr_xwayland->x_fd_read_event[0]);
-	wl_event_source_remove(wlr_xwayland->x_fd_read_event[1]);
-
-	wlr_xwayland->x_fd_read_event[0] = wlr_xwayland->x_fd_read_event[1] = NULL;
-
-	xwayland_start_server(wlr_xwayland);
-
-	return 0;
-}
-
-static bool xwayland_start_display(struct wlr_xwayland *wlr_xwayland,
-		struct wl_display *wl_display) {
-
-	wlr_xwayland->display_destroy.notify = handle_display_destroy;
-	wl_display_add_destroy_listener(wl_display, &wlr_xwayland->display_destroy);
-
-	wlr_xwayland->display = open_display_sockets(wlr_xwayland->x_fd);
-	if (wlr_xwayland->display < 0) {
-		xwayland_finish_display(wlr_xwayland);
-		return false;
-	}
-
-	snprintf(wlr_xwayland->display_name, sizeof(wlr_xwayland->display_name),
-		":%d", wlr_xwayland->display);
-	return true;
+	wl_signal_init(&xwayland->events.ready);
 }
 
-static bool xwayland_start_server(struct wlr_xwayland *wlr_xwayland) {
-	if (socketpair(AF_UNIX, SOCK_STREAM, 0, wlr_xwayland->wl_fd) != 0 ||
-			socketpair(AF_UNIX, SOCK_STREAM, 0, wlr_xwayland->wm_fd) != 0) {
-		wlr_log_errno(WLR_ERROR, "socketpair failed");
-		xwayland_finish_server(wlr_xwayland);
-		return false;
-	}
-	if (!set_cloexec(wlr_xwayland->wl_fd[0], true) ||
-			!set_cloexec(wlr_xwayland->wl_fd[1], true) ||
-			!set_cloexec(wlr_xwayland->wm_fd[0], true) ||
-			!set_cloexec(wlr_xwayland->wm_fd[1], true)) {
-		xwayland_finish_server(wlr_xwayland);
-		return false;
-	}
-
-	wlr_xwayland->server_start = time(NULL);
-
-	wlr_xwayland->client =
-		wl_client_create(wlr_xwayland->wl_display, wlr_xwayland->wl_fd[0]);
-	if (!wlr_xwayland->client) {
-		wlr_log_errno(WLR_ERROR, "wl_client_create failed");
-		xwayland_finish_server(wlr_xwayland);
-		return false;
-	}
-
-	wlr_xwayland->wl_fd[0] = -1; /* not ours anymore */
-
-	wlr_xwayland->client_destroy.notify = handle_client_destroy;
-	wl_client_add_destroy_listener(wlr_xwayland->client,
-		&wlr_xwayland->client_destroy);
-
-	struct wl_event_loop *loop = wl_display_get_event_loop(wlr_xwayland->wl_display);
-	wlr_xwayland->sigusr1_source = wl_event_loop_add_signal(loop, SIGUSR1,
-		xserver_handle_ready, wlr_xwayland);
-
-	wlr_xwayland->pid = fork();
-	if (wlr_xwayland->pid < 0) {
-		wlr_log_errno(WLR_ERROR, "fork failed");
-		xwayland_finish_server(wlr_xwayland);
-		return false;
-	} else if (wlr_xwayland->pid == 0) {
-		/* Double-fork, but we need to forward SIGUSR1 once Xserver(1)
-		 * is ready, or error if there was one. */
-		pid_t ppid = getppid();
-		sigset_t sigset;
-		sigemptyset(&sigset);
-		sigaddset(&sigset, SIGUSR1);
-		sigaddset(&sigset, SIGCHLD);
-		sigprocmask(SIG_BLOCK, &sigset, NULL);
-
-		pid_t pid = fork();
-		if (pid < 0) {
-			wlr_log_errno(WLR_ERROR, "second fork failed");
-			_exit(EXIT_FAILURE);
-		} else if (pid == 0) {
-			exec_xwayland(wlr_xwayland);
-		}
-
-		int sig;
-		sigwait(&sigset, &sig);
-		kill(ppid, SIGUSR1);
-		wlr_log(WLR_DEBUG, "sent SIGUSR1 to process %d", ppid);
-		if (sig == SIGCHLD) {
-			waitpid(pid, NULL, 0);
-			_exit(EXIT_FAILURE);
-		}
-
-		_exit(EXIT_SUCCESS);
-	}
-
-	/* close child fds */
-	/* remain managing x sockets for lazy start */
-	close(wlr_xwayland->wl_fd[1]);
-	close(wlr_xwayland->wm_fd[1]);
-	wlr_xwayland->wl_fd[1] = wlr_xwayland->wm_fd[1] = -1;
-
-	return true;
-}
-
-static bool xwayland_start_server_lazy(struct wlr_xwayland *wlr_xwayland) {
-	struct wl_event_loop *loop = wl_display_get_event_loop(wlr_xwayland->wl_display);
-	wlr_xwayland->x_fd_read_event[0] =
-		wl_event_loop_add_fd(loop, wlr_xwayland->x_fd[0], WL_EVENT_READABLE,
-				xwayland_socket_connected, wlr_xwayland);
-	wlr_xwayland->x_fd_read_event[1] =
-		wl_event_loop_add_fd(loop, wlr_xwayland->x_fd[1], WL_EVENT_READABLE,
-				xwayland_socket_connected, wlr_xwayland);
-
-	return true;
-}
-
-void wlr_xwayland_destroy(struct wlr_xwayland *wlr_xwayland) {
-	if (!wlr_xwayland) {
+void wlr_xwayland_destroy(struct wlr_xwayland *xwayland) {
+	if (!xwayland) {
 		return;
 	}
 
-	wlr_xwayland_set_seat(wlr_xwayland, NULL);
-	xwayland_finish_server(wlr_xwayland);
-	xwayland_finish_display(wlr_xwayland);
-	free(wlr_xwayland);
+	wl_list_remove(&xwayland->server_destroy.link);
+	wl_list_remove(&xwayland->server_ready.link);
+
+	wlr_xwayland_set_seat(xwayland, NULL);
+	wlr_xwayland_server_destroy(xwayland->server);
+	free(xwayland);
 }
 
 struct wlr_xwayland *wlr_xwayland_create(struct wl_display *wl_display,
 		struct wlr_compositor *compositor, bool lazy) {
-	struct wlr_xwayland *wlr_xwayland = calloc(1, sizeof(struct wlr_xwayland));
-	if (!wlr_xwayland) {
+	struct wlr_xwayland *xwayland = calloc(1, sizeof(struct wlr_xwayland));
+	if (!xwayland) {
 		return NULL;
 	}
 
-	wlr_xwayland->wl_display = wl_display;
-	wlr_xwayland->compositor = compositor;
-	wlr_xwayland->lazy = lazy;
+	xwayland->wl_display = wl_display;
+	xwayland->compositor = compositor;
 
-	wlr_xwayland->x_fd[0] = wlr_xwayland->x_fd[1] = -1;
-	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(&xwayland->events.new_surface);
+	wl_signal_init(&xwayland->events.ready);
 
-	wl_signal_init(&wlr_xwayland->events.new_surface);
-	wl_signal_init(&wlr_xwayland->events.ready);
-
-	if (!xwayland_start_display(wlr_xwayland, wl_display)) {
-		goto error_alloc;
+	xwayland->server = wlr_xwayland_server_create(wl_display, lazy);
+	if (xwayland->server == NULL) {
+		free(xwayland->server);
+		return NULL;
 	}
 
-	if (wlr_xwayland->lazy) {
-		if (!xwayland_start_server_lazy(wlr_xwayland)) {
-			goto error_display;
-		}
-	} else {
-		if (!xwayland_start_server(wlr_xwayland)) {
-			goto error_display;
-		}
-	}
+	xwayland->display_name = xwayland->server->display_name;
 
-	return wlr_xwayland;
+	xwayland->server_destroy.notify = handle_server_destroy;
+	wl_signal_add(&xwayland->server->events.destroy, &xwayland->server_destroy);
 
-error_display:
-	xwayland_finish_display(wlr_xwayland);
+	xwayland->server_ready.notify = handle_server_ready;
+	wl_signal_add(&xwayland->server->events.ready, &xwayland->server_ready);
 
-error_alloc:
-	free(wlr_xwayland);
-	return NULL;
+	return xwayland;
 }
 
-void wlr_xwayland_set_cursor(struct wlr_xwayland *wlr_xwayland,
+void wlr_xwayland_set_cursor(struct wlr_xwayland *xwayland,
 		uint8_t *pixels, uint32_t stride, uint32_t width, uint32_t height,
 		int32_t hotspot_x, int32_t hotspot_y) {
-	if (wlr_xwayland->xwm != NULL) {
-		xwm_set_cursor(wlr_xwayland->xwm, pixels, stride, width, height,
+	if (xwayland->xwm != NULL) {
+		xwm_set_cursor(xwayland->xwm, pixels, stride, width, height,
 			hotspot_x, hotspot_y);
 		return;
 	}
 
-	free(wlr_xwayland->cursor);
+	free(xwayland->cursor);
 
-	wlr_xwayland->cursor = calloc(1, sizeof(struct wlr_xwayland_cursor));
-	if (wlr_xwayland->cursor == NULL) {
+	xwayland->cursor = calloc(1, sizeof(struct wlr_xwayland_cursor));
+	if (xwayland->cursor == NULL) {
 		return;
 	}
-	wlr_xwayland->cursor->pixels = pixels;
-	wlr_xwayland->cursor->stride = stride;
-	wlr_xwayland->cursor->width = width;
-	wlr_xwayland->cursor->height = height;
-	wlr_xwayland->cursor->hotspot_x = hotspot_x;
-	wlr_xwayland->cursor->hotspot_y = hotspot_y;
+	xwayland->cursor->pixels = pixels;
+	xwayland->cursor->stride = stride;
+	xwayland->cursor->width = width;
+	xwayland->cursor->height = height;
+	xwayland->cursor->hotspot_x = hotspot_x;
+	xwayland->cursor->hotspot_y = hotspot_y;
 }
 
 static void xwayland_handle_seat_destroy(struct wl_listener *listener,