subdaemons: handle master or gossipd failing.

We should simply exit in this case.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/channel/channel.c

@@ -1356,6 +1356,18 @@ out:
 }
 
 #ifndef TESTING
+static void master_gone(struct io_conn *unused, struct daemon_conn *dc)
+{
+	/* Can't tell master, it's gone. */
+	exit(2);
+}
+
+static void gossip_gone(struct io_conn *unused, struct daemon_conn *dc)
+{
+	status_failed(WIRE_CHANNEL_GOSSIP_BAD_MESSAGE,
+		      "Gossip connection closed");
+}
+
 int main(int argc, char *argv[])
 {
 	struct peer *peer = tal(NULL, struct peer);
@@ -1373,7 +1385,7 @@ int main(int argc, char *argv[])
 	secp256k1_ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY
 						 | SECP256K1_CONTEXT_SIGN);
 
-	daemon_conn_init(peer, &peer->master, REQ_FD, req_in);
+	daemon_conn_init(peer, &peer->master, REQ_FD, req_in, master_gone);
 	peer->channel = NULL;
 	peer->htlc_id = 0;
 	peer->num_pings_outstanding = 0;
@@ -1397,7 +1409,7 @@ int main(int argc, char *argv[])
 	msg_queue_init(&peer->peer_out, peer);
 
 	daemon_conn_init(peer, &peer->gossip_client, GOSSIP_FD,
-			 gossip_client_recv);
+			 gossip_client_recv, gossip_gone);
 
 	init_peer_crypto_state(peer, &peer->pcs);
 	peer->funding_locked[LOCAL] = peer->funding_locked[REMOTE] = false;

lightningd/daemon_conn.c

@@ -62,15 +62,20 @@ static struct io_plan *daemon_conn_start(struct io_conn *conn,
 
 void daemon_conn_init(tal_t *ctx, struct daemon_conn *dc, int fd,
 		      struct io_plan *(*daemon_conn_recv)(struct io_conn *,
-							  struct daemon_conn *))
+							  struct daemon_conn *),
+		      void (*finish)(struct io_conn *, struct daemon_conn *dc))
 {
+	struct io_conn *conn;
+
 	dc->daemon_conn_recv = daemon_conn_recv;
 
 	dc->ctx = ctx;
 	dc->msg_in = NULL;
 	msg_queue_init(&dc->out, dc->ctx);
 	dc->msg_queue_cleared_cb = NULL;
-	io_new_conn(ctx, fd, daemon_conn_start, dc);
+	conn = io_new_conn(ctx, fd, daemon_conn_start, dc);
+	if (finish)
+		io_set_finish(conn, finish, dc);
 }
 
 void daemon_conn_send(struct daemon_conn *dc, const u8 *msg)

lightningd/daemon_conn.h

@@ -37,10 +37,12 @@ struct daemon_conn {
  * @dc: daemon_conn to initialize
  * @fd: socket file descriptor to wrap
  * @daemon_conn_recv: callback function to be called upon receiving a message
+ * @finish: finish function if connection is closed (can be NULL)
  */
 void daemon_conn_init(tal_t *ctx, struct daemon_conn *dc, int fd,
 		      struct io_plan *(*daemon_conn_recv)(
-			  struct io_conn *, struct daemon_conn *));
+			  struct io_conn *, struct daemon_conn *),
+		      void (*finish)(struct io_conn *, struct daemon_conn *));
 /**
  * daemon_conn_send - Enqueue an outgoing message to be sent
  */

lightningd/gossip/gossip.c

@@ -145,7 +145,7 @@ static void send_peer_with_fds(struct peer *peer, const u8 *msg)
 	/* Now we talk to socket to get to peer's owner daemon. */
 	peer->local = false;
 	/* FIXME: Forget peer if other end is closed. */
-	daemon_conn_init(peer, &peer->owner_conn, fds[0], owner_msg_in);
+	daemon_conn_init(peer, &peer->owner_conn, fds[0], owner_msg_in, NULL);
 	peer->owner_conn.msg_queue_cleared_cb = nonlocal_dump_gossip;
 
 	/* Peer stays around, even though we're going to free conn. */
@@ -700,6 +700,12 @@ static struct io_plan *recv_req(struct io_conn *conn, struct daemon_conn *master
 }
 
 #ifndef TESTING
+static void master_gone(struct io_conn *unused, struct daemon_conn *dc)
+{
+	/* Can't tell master, it's gone. */
+	exit(2);
+}
+
 int main(int argc, char *argv[])
 {
 	struct daemon *daemon;
@@ -728,7 +734,8 @@ int main(int argc, char *argv[])
 	daemon->broadcast_interval = 30000;
 
 	/* stdin == control */
-	daemon_conn_init(daemon, &daemon->master, STDIN_FILENO, recv_req);
+	daemon_conn_init(daemon, &daemon->master, STDIN_FILENO, recv_req,
+			 master_gone);
 	status_setup_async(&daemon->master);
 
 	/* When conn closes, everything is freed. */

lightningd/hsm/hsm.c

@@ -82,7 +82,7 @@ static struct client *new_client(struct daemon_conn *master,
 	c->id = id;
 	c->handle = handle;
 	c->master = master;
-	daemon_conn_init(c, &c->dc, fd, handle);
+	daemon_conn_init(c, &c->dc, fd, handle, NULL);
 
 	/* Free the connection if we exit everything. */
 	tal_steal(master, c->dc.conn);
@@ -586,6 +586,12 @@ static struct io_plan *control_received_req(struct io_conn *conn,
 }
 
 #ifndef TESTING
+static void master_gone(struct io_conn *unused, struct daemon_conn *dc)
+{
+	/* Can't tell master, it's gone. */
+	exit(2);
+}
+
 int main(int argc, char *argv[])
 {
 	struct daemon_conn *master;
@@ -600,7 +606,8 @@ int main(int argc, char *argv[])
 						 | SECP256K1_CONTEXT_SIGN);
 
 	master = tal(NULL, struct daemon_conn);
-	daemon_conn_init(master, master, STDIN_FILENO, control_received_req);
+	daemon_conn_init(master, master, STDIN_FILENO, control_received_req,
+			 master_gone);
 	status_setup_async(master);
 
 	/* When conn closes, everything is freed. */