seatd: cleaning up

seatd/vt.patch

@@ -1,186 +0,0 @@
-From 2eee9aa445e3f9dc6a7ca115489f87b10f60b9ba Mon Sep 17 00:00:00 2001
-From: Kenny Levinsen <kl@kl.wtf>
-Date: Mon, 20 Sep 2021 23:43:10 +0200
-Subject: [PATCH] seatd: Implement ping request to wake up later
-
-When device open or close messages are sent to seatd, libseat must read
-messages from the socket until it sees the associated response message.
-This means that it may drain enable/disable seat events from the socket,
-queueing them internally for deferred processing.
-
-As the socket is drained, the caller will not wake from a poll and have
-no reason to dispatch libseat. To ensure that these messages would not
-be left in the queue, 6fa82930d0c5660eea3102989c765dc864514e36 made it
-so that open/close calls would execute all queued events just before
-returning.
-
-Unfortunately, this had the side-effect of having events fire from the
-stack of libseat_open_device or libseat_close_device, which we now see
-cause problems in compositors. Specifically, an issue has been observed
-where libinput end up calling libseat_close_device, which in turn
-dispatch a disable seat event that calls libinput_suspend. libinput does
-not like this.
-
-Instead, remove the execution from libseat_open_device and
-libseat_close_device, and instead make a "ping" request to seatd if
-events have been queued. The response to this will wake us up and ensure
-that dispatch is called.
----
- include/protocol.h      |  2 ++
- libseat/backend/seatd.c | 45 +++++++++++++++++++++++++++++++++++++----
- seatd/client.c          | 22 ++++++++++++++++++++
- 3 files changed, 65 insertions(+), 4 deletions(-)
-
-diff --git a/include/protocol.h b/include/protocol.h
-index b3361ba..cb994fc 100644
---- a/include/protocol.h
-+++ b/include/protocol.h
-@@ -15,6 +15,7 @@
- #define CLIENT_CLOSE_DEVICE   CLIENT_EVENT(4)
- #define CLIENT_DISABLE_SEAT   CLIENT_EVENT(5)
- #define CLIENT_SWITCH_SESSION CLIENT_EVENT(6)
-+#define CLIENT_PING	      CLIENT_EVENT(7)
- 
- #define SERVER_SEAT_OPENED   SERVER_EVENT(1)
- #define SERVER_SEAT_CLOSED   SERVER_EVENT(2)
-@@ -22,6 +23,7 @@
- #define SERVER_DEVICE_CLOSED SERVER_EVENT(4)
- #define SERVER_DISABLE_SEAT  SERVER_EVENT(5)
- #define SERVER_ENABLE_SEAT   SERVER_EVENT(6)
-+#define SERVER_PONG	     SERVER_EVENT(7)
- #define SERVER_ERROR	     SERVER_EVENT(0x7FFF)
- 
- #include <stdint.h>
-diff --git a/libseat/backend/seatd.c b/libseat/backend/seatd.c
-index 85df9f5..26308d1 100644
---- a/libseat/backend/seatd.c
-+++ b/libseat/backend/seatd.c
-@@ -36,6 +36,7 @@ struct backend_seatd {
- 	const struct libseat_seat_listener *seat_listener;
- 	void *seat_listener_data;
- 	struct linked_list pending_events;
-+	bool awaiting_pong;
- 	bool error;
- 
- 	char seat_name[MAX_SEAT_LEN];
-@@ -243,6 +244,12 @@ static int dispatch_pending(struct backend_seatd *backend, int *opcode) {
- 	while (connection_get(&backend->connection, &header, sizeof header) != -1) {
- 		packets++;
- 		switch (header.opcode) {
-+		case SERVER_PONG:
-+			// We care about whether or not the answer has been
-+			// read from the connection, so handle it here instead
-+			// of pushing it to the pending event list.
-+			backend->awaiting_pong = false;
-+			break;
- 		case SERVER_DISABLE_SEAT:
- 		case SERVER_ENABLE_SEAT:
- 			if (queue_event(backend, header.opcode) == -1) {
-@@ -450,6 +457,36 @@ static const char *seat_name(struct libseat *base) {
- 	return backend->seat_name;
- }
- 
-+static int send_ping(struct backend_seatd *backend) {
-+	struct proto_header header = {
-+		.opcode = CLIENT_PING,
-+		.size = 0,
-+	};
-+	if (conn_put(backend, &header, sizeof header) == -1 || conn_flush(backend) == -1) {
-+		return -1;
-+	}
-+	return 0;
-+}
-+
-+static void check_pending_events(struct backend_seatd *backend) {
-+	if (linked_list_empty(&backend->pending_events)) {
-+		return;
-+	}
-+	if (backend->awaiting_pong) {
-+		return;
-+	}
-+
-+	// We have events pending execution, so a dispatch is required.
-+	// However, we likely already drained our socket, so there will not be
-+	// anything to read. Instead, send a ping request to seatd, so that the
-+	// user will be woken up by its response.
-+	if (send_ping(backend) == -1) {
-+		log_errorf("Could not send ping request: %s", strerror(errno));
-+		return;
-+	}
-+	backend->awaiting_pong = true;
-+}
-+
- static int open_device(struct libseat *base, const char *path, int *fd) {
- 	struct backend_seatd *backend = backend_seatd_from_libseat_backend(base);
- 	if (backend->error) {
-@@ -481,11 +518,11 @@ static int open_device(struct libseat *base, const char *path, int *fd) {
- 		goto error;
- 	}
- 
--	execute_events(backend);
-+	check_pending_events(backend);
- 	return rmsg.device_id;
- 
- error:
--	execute_events(backend);
-+	check_pending_events(backend);
- 	return -1;
- }
- 
-@@ -516,11 +553,11 @@ static int close_device(struct libseat *base, int device_id) {
- 		goto error;
- 	}
- 
--	execute_events(backend);
-+	check_pending_events(backend);
- 	return 0;
- 
- error:
--	execute_events(backend);
-+	check_pending_events(backend);
- 	return -1;
- }
- 
-diff --git a/seatd/client.c b/seatd/client.c
-index 1bfe94a..220c5d3 100644
---- a/seatd/client.c
-+++ b/seatd/client.c
-@@ -309,6 +309,20 @@ error:
- 	return client_send_error(client, errno);
- }
- 
-+static int handle_ping(struct client *client) {
-+	struct proto_header header = {
-+		.opcode = SERVER_PONG,
-+		.size = 0,
-+	};
-+
-+	if (connection_put(&client->connection, &header, sizeof header) == -1) {
-+		log_errorf("Could not write response: %s", strerror(errno));
-+		return -1;
-+	}
-+
-+	return 0;
-+}
-+
- static int client_handle_opcode(struct client *client, uint16_t opcode, size_t size) {
- 	int res = 0;
- 	switch (opcode) {
-@@ -372,6 +386,14 @@ static int client_handle_opcode(struct client *client, uint16_t opcode, size_t s
- 		res = handle_disable_seat(client);
- 		break;
- 	}
-+	case CLIENT_PING: {
-+		if (size != 0) {
-+			log_error("Protocol error: invalid ping message");
-+			return -1;
-+		}
-+		res = handle_ping(client);
-+		break;
-+	}
- 	default:
- 		log_errorf("Protocol error: unknown opcode: %d", opcode);
- 		res = -1;
--- 
-2.32.0
-