lightningd: add dev-fail command to inject permenant failure.

A couple of double-free bugs founnd doing this, too.

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

lightningd/peer_control.c

@@ -59,6 +59,8 @@ static void reconnect_failed(struct lightningd_state *dstate,
 	struct lightningd *ld = ld_from_dstate(dstate);
 	struct peer *peer = peer_by_id(ld, connection_known_id(c));
 
+	log_debug(peer->log, "reconnect_failed");
+
 	tal_free(c);
 	peer_reconnect(peer);
 }
@@ -68,6 +70,8 @@ static void try_reconnect(struct peer *peer)
 	struct connection *c;
 	struct netaddr *addrs;
 
+	log_debug(peer->log, "try_reconnect: trying to reconnect");
+
 	/* We may already be reconnected (another incoming connection) */
 	if (peer->owner) {
 		log_debug(peer->log, "try_reconnect: already reconnected (%s)",
@@ -109,7 +113,7 @@ void peer_fail_permanent(struct peer *peer, const u8 *msg)
 		    peer_state_name(peer->state),
 		    (int)tal_len(msg), (char *)msg);
 	peer->error = towire_error(peer, &all_channels, msg);
-	peer->owner = NULL;
+	peer->owner = tal_free(peer->owner);
 	if (taken(msg))
 		tal_free(msg);
 
@@ -202,6 +206,7 @@ static void peer_start_closingd(struct peer *peer,
 static struct io_plan *send_error(struct io_conn *conn,
 				  struct peer_crypto_state *pcs)
 {
+	log_debug(pcs->peer->log, "Sending canned error");
 	return peer_write_message(conn, pcs, pcs->peer->error, (void *)io_close_cb);
 }
 
@@ -720,6 +725,38 @@ static const struct json_command connect_command = {
 };
 AUTODATA(json_command, &connect_command);
 
+static void json_dev_fail(struct command *cmd,
+			  const char *buffer, const jsmntok_t *params)
+{
+	struct lightningd *ld = ld_from_dstate(cmd->dstate);
+	jsmntok_t *peertok;
+	struct peer *peer;
+
+	if (!json_get_params(buffer, params,
+			     "id", &peertok,
+			     NULL)) {
+		command_fail(cmd, "Need id");
+		return;
+	}
+
+	peer = peer_from_json(ld, buffer, peertok);
+	if (!peer) {
+		command_fail(cmd, "Could not find peer with that id");
+		return;
+	}
+
+	peer_internal_error(peer, "Failing due to dev-fail command");
+	command_success(cmd, null_response(cmd));
+}
+
+static const struct json_command dev_fail_command = {
+	"dev-fail",
+	json_dev_fail,
+	"Fail with peer {id}",
+	"Returns {} on success"
+};
+AUTODATA(json_command, &dev_fail_command);
+
 struct log_info {
 	enum log_level level;
 	struct json_result *response;

lightningd/subd.c

@@ -371,6 +371,11 @@ static void destroy_subd(struct subd *sd)
 		status = -1;
 		break;
 	}
+
+	/* In case we're freed manually, such as peer_fail_permanent */
+	if (sd->conn)
+		sd->conn = tal_free(sd->conn);
+
 	log_debug(sd->log, "finishing: %p", sd->finished);
 	if (sd->finished)
 		sd->finished(sd, status);

tests/test_lightningd.py

@@ -336,6 +336,20 @@ class LightningDTests(BaseLightningDTests):
         l2.daemon.wait_for_log('sendrawtx exit 0')
         assert l1.bitcoin.rpc.getmempoolinfo()['size'] == 1
 
+    def test_permfail(self):
+        l1,l2 = self.connect()
+
+        self.fund_channel(l1, l2, 10**6)
+        self.pay(l1,l2,200000000)
+
+        # We fail l2, so l1 will reconnect to it.
+        l2.rpc.dev_fail(l1.info['id']);
+        l2.daemon.wait_for_log('Failing due to dev-fail command')
+        l2.daemon.wait_for_log('sendrawtx exit 0')
+
+        # "Internal error" in hex
+        l1.daemon.wait_for_log('WIRE_ERROR.*496e7465726e616c206572726f72')
+
     def test_gossip_jsonrpc(self):
         l1,l2 = self.connect()