openingd: use wirestring instead of u8 array for why negotiation failed.

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

lightningd/peer_control.c

@@ -2412,15 +2412,14 @@ static unsigned int opening_negotiation_failed(struct subd *openingd,
 	struct crypto_state cs;
 	u64 gossip_index;
 	struct peer *peer = openingd->peer;
-	u8 *err;
-	const char *why;
+	char *why;
 
 	/* We need the peer fd and gossip fd. */
 	if (tal_count(fds) == 0)
 		return 2;
 
 	if (!fromwire_opening_negotiation_failed(msg, msg, NULL,
-						 &cs, &gossip_index, &err)) {
+						 &cs, &gossip_index, &why)) {
 		peer_internal_error(peer,
 				    "bad OPENING_NEGOTIATION_FAILED %s",
 				    tal_hex(msg, msg));
@@ -2433,7 +2432,6 @@ static unsigned int opening_negotiation_failed(struct subd *openingd,
 	subd_send_fd(openingd->ld->gossip, fds[0]);
 	subd_send_fd(openingd->ld->gossip, fds[1]);
 
-	why = tal_strndup(peer, (const char *)err, tal_len(err));
 	log_unusual(peer->log, "Opening negotiation failed: %s", why);
 
 	/* This will free openingd, since that's peer->owner */

openingd/opening.c

@@ -91,7 +91,7 @@ static void negotiation_failed(struct state *state, bool send_error,
 	/* Tell master we should return to gossiping. */
 	msg = towire_opening_negotiation_failed(state, &state->cs,
 						state->gossip_index,
-						(const u8 *)errmsg);
+						errmsg);
 	wire_sync_write(REQ_FD, msg);
 	fdpass_send(REQ_FD, PEER_FD);
 	fdpass_send(REQ_FD, GOSSIP_FD);

openingd/opening_wire.csv

@@ -81,7 +81,5 @@ opening_fundee_reply,,funding_signed_msg,msglen*u8
 opening_negotiation_failed,6010
 opening_negotiation_failed,,crypto_state,struct crypto_state
 opening_negotiation_failed,,gossip_index,u64
-opening_negotiation_failed,,len,u16
-# FIXME: string support!
-opening_negotiation_failed,,msg,len*u8
+opening_negotiation_failed,,msg,wirestring