seat: Deactivate devices before sending disable

Previously, seatd would not deactivate devices until the client had
acked the disable. In once instance, this lead to libinput spending
significant time checking and closing each input device.

As a workaround, mimick logind's behavior of deactivating devices first.
The original behavior can be reintroduced if the client-side problem is
fixed.

Closes: https://todo.sr.ht/~kennylevinsen/seatd/5

1 files changed, 99 insertions, 32 deletions

diff --git a/seatd/seat.c b/seatd/seat.c
index f9756dc..bbbfed7 100644
--- a/seatd/seat.c
+++ b/seatd/seat.c
@@ -70,10 +70,11 @@ int seat_add_client(struct seat *seat, struct client *client) {
 	return 0;
 }
 
-int seat_remove_client(struct seat *seat, struct client *client) {
-	assert(seat);
+int seat_remove_client(struct client *client) {
 	assert(client);
-	assert(client->seat == seat);
+	assert(client->seat);
+
+	struct seat *seat = client->seat;
 
 	// We must first remove the client to avoid reactivation
 	bool found = false;
@@ -95,12 +96,12 @@ int seat_remove_client(struct seat *seat, struct client *client) {
 	}
 
 	while (client->devices.length > 0) {
-		struct seat_device *device = client->devices.items[client->devices.length - 1];
+		struct seat_device *device = list_pop_back(&client->devices);
 		seat_close_device(client, device);
 	}
 
 	if (seat->active_client == client) {
-		seat_close_client(seat, client);
+		seat_close_client(client);
 	}
 
 	client->seat = NULL;
@@ -135,6 +136,11 @@ struct seat_device *seat_open_device(struct client *client, const char *path) {
 		return NULL;
 	}
 
+	if (client->pending_disable) {
+		errno = EPERM;
+		return NULL;
+	}
+
 	char sanitized_path[PATH_MAX];
 	if (realpath(path, sanitized_path) == NULL) {
 		log_errorf("invalid path '%s': %s", path, strerror(errno));
@@ -375,7 +381,7 @@ int seat_open_client(struct seat *seat, struct client *client) {
 
 	seat->active_client = client;
 	if (client_enable_seat(client) == -1) {
-		seat_remove_client(seat, client);
+		seat_remove_client(client);
 		return -1;
 	}
 
@@ -383,9 +389,37 @@ int seat_open_client(struct seat *seat, struct client *client) {
 	return 0;
 }
 
-int seat_close_client(struct seat *seat, struct client *client) {
-	assert(seat);
+int seat_close_client(struct client *client) {
+	assert(client);
+	assert(client->seat);
+
+	struct seat *seat = client->seat;
+
+	if (seat->active_client != client) {
+		log_error("client not active");
+		errno = EBUSY;
+		return -1;
+	}
+
+	while (client->devices.length > 0) {
+		struct seat_device *device = list_pop_back(&client->devices);
+		if (seat_close_device(client, device) == -1) {
+			log_errorf("unable to close '%s': %s", device->path, strerror(errno));
+		}
+	}
+
+	client->pending_disable = false;
+	seat->active_client = NULL;
+	seat_activate(seat);
+	log_debug("closed client");
+	return 0;
+}
+
+static int seat_disable_client(struct client *client) {
 	assert(client);
+	assert(client->seat);
+
+	struct seat *seat = client->seat;
 
 	if (seat->active_client != client) {
 		log_error("client not active");
@@ -406,37 +440,62 @@ int seat_close_client(struct seat *seat, struct client *client) {
 
 	log_debugf("deactivated %zd devices", client->devices.length);
 
-	seat->active_client = NULL;
+	client->pending_disable = true;
+	if (client_disable_seat(seat->active_client) == -1) {
+		seat_remove_client(client);
+		return -1;
+	}
 
-	if (seat->vt_bound && seat->vt_pending_ack) {
-		log_debug("acking pending VT switch");
-		seat->vt_pending_ack = false;
-		assert(seat->curttyfd != -1);
-		terminal_set_process_switching(seat->curttyfd, true);
-		terminal_set_keyboard(seat->curttyfd, true);
-		terminal_set_graphics(seat->curttyfd, false);
-		terminal_ack_switch(seat->curttyfd);
-		close(seat->curttyfd);
-		seat->curttyfd = -1;
-		return 0;
+	log_debug("disabling client");
+	return 0;
+}
+
+int seat_ack_disable_client(struct client *client) {
+	assert(client);
+	assert(client->seat);
+
+	struct seat *seat = client->seat;
+
+	if (seat->active_client != client || !client->pending_disable) {
+		log_error("client not active or not pending disable");
+		errno = EBUSY;
+		return -1;
 	}
 
+	client->pending_disable = false;
+	seat->active_client = NULL;
 	seat_activate(seat);
-	log_debug("closed client");
+	log_debug("disabled client");
 	return 0;
 }
 
-int seat_set_next_session(struct seat *seat, int session) {
-	assert(seat);
+int seat_set_next_session(struct client *client, int session) {
+	assert(client);
+	assert(client->seat);
+
+	struct seat *seat = client->seat;
+
+	if (seat->active_client != client || client->pending_disable) {
+		log_error("client not active or pending disable");
+		errno = EPERM;
+		return -1;
+	}
+
+	if (session == client_get_session(client)) {
+		log_info("requested session is already active");
+		return 0;
+	}
 
 	// Check if the session number is valid
 	if (session <= 0) {
+		log_errorf("invalid session value: %d", session);
 		errno = EINVAL;
 		return -1;
 	}
 
 	// Check if a switch is already queued
 	if (seat->next_vt > 0 || seat->next_client != NULL) {
+		log_info("switch is already queued");
 		return 0;
 	}
 
@@ -463,10 +522,7 @@ int seat_set_next_session(struct seat *seat, int session) {
 		return -1;
 	}
 
-	if (client_disable_seat(seat->active_client) == -1) {
-		seat_remove_client(seat, seat->active_client);
-	}
-
+	seat_disable_client(seat->active_client);
 	return 0;
 }
 
@@ -486,6 +542,20 @@ int seat_activate(struct seat *seat) {
 			return -1;
 		}
 
+		// If we need to ack a switch, do that
+		if (seat->vt_pending_ack) {
+			log_info("acking pending VT switch");
+			seat->vt_pending_ack = false;
+			if (seat->curttyfd != -1) {
+				terminal_set_process_switching(seat->curttyfd, false);
+				terminal_set_keyboard(seat->curttyfd, true);
+				terminal_set_graphics(seat->curttyfd, false);
+				close(seat->curttyfd);
+				seat->curttyfd = -1;
+			}
+			return 0;
+		}
+
 		// If we're asked to do a simple VT switch, do that
 		if (seat->next_vt > 0) {
 			log_info("executing VT switch");
@@ -568,16 +638,13 @@ int seat_prepare_vt_switch(struct seat *seat) {
 
 	if (seat->vt_pending_ack) {
 		log_info("impatient user, killing session to force pending switch");
-		seat_close_client(seat, seat->active_client);
+		seat_close_client(seat->active_client);
 		return 0;
 	}
 
 	log_debug("delaying VT switch acknowledgement");
 
 	seat->vt_pending_ack = true;
-	if (client_disable_seat(seat->active_client) == -1) {
-		seat_remove_client(seat, seat->active_client);
-	}
-
+	seat_disable_client(seat->active_client);
 	return 0;
 }