daemon_conn: fix daemon_conn_sync_flush.

We need to set fd to blocking before trying to sync write.  Use
io_fd_block() elsewhere, too.

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

lightningd/daemon_conn.c

@@ -35,21 +35,30 @@ struct io_plan *daemon_conn_write_next(struct io_conn *conn,
 bool daemon_conn_sync_flush(struct daemon_conn *dc)
 {
 	const u8 *msg;
+	int daemon_fd;
 
 	/* Flush any current packet. */
 	if (!io_flush_sync(dc->conn))
 		return false;
 
+	/* Make fd blocking for the duration */
+	daemon_fd = io_conn_fd(dc->conn);
+	if (!io_fd_block(daemon_fd, true))
+		return false;
+
 	/* Flush existing messages. */
 	while ((msg = msg_dequeue(&dc->out)) != NULL) {
 		int fd = msg_extract_fd(msg);
 		if (fd >= 0) {
-			if (!fdpass_send(io_conn_fd(dc->conn), fd))
-				return false;
-		} else if (!wire_sync_write(io_conn_fd(dc->conn), take(msg)))
-			return false;
+			if (!fdpass_send(daemon_fd, fd))
+				break;
+		} else if (!wire_sync_write(daemon_fd, take(msg)))
+			break;
 	}
-	return true;
+	io_fd_block(daemon_fd, false);
+
+	/* Success iff we flushed them all. */
+	return msg == NULL;
 }
 
 static struct io_plan *daemon_conn_start(struct io_conn *conn,

lightningd/new_connection.c

@@ -41,18 +41,6 @@ static void connection_destroy(struct connection *c)
 		command_fail(c->cmd, "Failed to connect to peer");
 }
 
-static void set_blocking(int fd, bool block)
-{
-	int flags = fcntl(fd, F_GETFL);
-
-	if (block)
-		flags &= ~O_NONBLOCK;
-	else
-		flags |= O_NONBLOCK;
-
-	fcntl(fd, F_SETFL, flags);
-}
-
 static void
 PRINTF_FMT(3,4) connection_failed(struct connection *c, struct log *log,
 				  const char *fmt, ...)
@@ -202,7 +190,7 @@ static struct io_plan *hsm_then_handshake(struct io_conn *conn,
 		fatal("Could not read fd from HSM: %s", strerror(errno));
 
 	/* Make sure connection fd is blocking */
-	set_blocking(connfd, true);
+	io_fd_block(connfd, true);
 
 	/* Give handshake daemon the hsm fd. */
 	handshaked = new_subd(ld, ld,

lightningd/peer_failed.c

@@ -1,3 +1,4 @@
+#include <ccan/io/io.h>
 #include <ccan/tal/str/str.h>
 #include <fcntl.h>
 #include <lightningd/crypto_sync.h>
@@ -35,7 +36,7 @@ void peer_failed(int peer_fd, struct crypto_state *cs,
 	msg = towire_error(errmsg, channel_id, (const u8 *)errmsg);
 
 	/* This is only best-effort; don't block. */
-	fcntl(peer_fd, F_SETFL, fcntl(peer_fd, F_GETFL) | O_NONBLOCK);
+	io_fd_block(peer_fd, false);
 	sync_crypto_write(cs, peer_fd, take(msg));
 
 	status_failed(error_code, "%s", errmsg);

lightningd/subd.c

@@ -27,19 +27,6 @@ static bool move_fd(int from, int to)
 	return true;
 }
 
-/* FIXME: Expose the ccan/io version? */
-static void set_blocking(int fd, bool block)
-{
-	int flags = fcntl(fd, F_GETFL);
-
-	if (block)
-		flags &= ~O_NONBLOCK;
-	else
-		flags |= O_NONBLOCK;
-
-	fcntl(fd, F_SETFL, flags);
-}
-
 struct subd_req {
 	struct list_node list;
 
@@ -281,7 +268,7 @@ static struct io_plan *read_fds(struct io_conn *conn, struct subd *sd)
 
 		/* Don't trust subd to set it blocking. */
 		for (i = 0; i < tal_count(sd->fds_in); i++)
-			set_blocking(sd->fds_in[i], true);
+			io_fd_block(sd->fds_in[i], true);
 		return sd_msg_read(conn, sd);
 	}
 	return io_recv_fd(conn, &sd->fds_in[sd->num_fds_in_read++],