Start X11 and web frontends for xC

For this, we needed a wire protocol.  After surveying available options,
it was decided to implement an XDR-like protocol code generator
in portable AWK.  It now has two backends, per each of:

 - xF, the X11 frontend, is in C, and is meant to be the primary
   user interface in the future.

 - xP, the web frontend, relies on a protocol proxy written in Go,
   and is meant for use on-the-go (no pun intended).

They are very much work-in-progress proofs of concept right now,
and the relay protocol is certain to change.

1 files changed, 12 insertions, 27 deletions

diff --git a/xD.c b/xD.c
index 45cd659..65ebe7e 100644
--- a/xD.c
+++ b/xD.c
@@ -853,8 +853,6 @@ client_send_str (struct client *c, const struct str *s)
 	str_append_data (&c->write_buffer, s->str,
 		MIN (s->len, IRC_MAX_MESSAGE_LENGTH));
 	str_append (&c->write_buffer, "\r\n");
-	// XXX: we might want to move this elsewhere, so that it doesn't get called
-	//   as often; it's going to cause a lot of syscalls with epoll.
 	client_update_poller (c, NULL);
 
 	// Technically we haven't sent it yet but that's a minor detail
@@ -3095,6 +3093,7 @@ irc_try_read (struct client *c)
 		{
 			buf->str[buf->len += n_read] = '\0';
 			// TODO: discard characters above the 512 character limit
+			// FIXME: we should probably discard the data if closing_link
 			irc_process_buffer (buf, irc_process_message, c);
 			continue;
 		}
@@ -3136,6 +3135,7 @@ irc_try_read_tls (struct client *c)
 		case SSL_ERROR_NONE:
 			buf->str[buf->len += n_read] = '\0';
 			// TODO: discard characters above the 512 character limit
+			// FIXME: we should probably discard the data if closing_link
 			irc_process_buffer (buf, irc_process_message, c);
 			continue;
 		case SSL_ERROR_ZERO_RETURN:
@@ -3421,16 +3421,10 @@ irc_try_fetch_client (struct server_context *ctx, int listen_fd)
 		if (errno == EINTR)
 			return true;
 
-		if (errno == EBADF
-		 || errno == EINVAL
-		 || errno == ENOTSOCK
-		 || errno == EOPNOTSUPP)
+		if (accept_error_is_transient (errno))
+			print_warning ("%s: %s", "accept", strerror (errno));
+		else
 			print_fatal ("%s: %s", "accept", strerror (errno));
-
-		// OS kernels may return a wide range of unforeseeable errors.
-		// Assuming that they're either transient or caused by
-		// a connection that we've just extracted from the queue.
-		print_warning ("%s: %s", "accept", strerror (errno));
 		return true;
 	}
 
@@ -3814,10 +3808,9 @@ irc_lock_pid_file (struct server_context *ctx, struct error **e)
 }
 
 static int
-irc_listen (struct addrinfo *gai_iter)
+irc_listen (struct addrinfo *ai)
 {
-	int fd = socket (gai_iter->ai_family,
-		gai_iter->ai_socktype, gai_iter->ai_protocol);
+	int fd = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 	if (fd == -1)
 		return -1;
 	set_cloexec (fd);
@@ -3831,21 +3824,13 @@ irc_listen (struct addrinfo *gai_iter)
 #if defined SOL_IPV6 && defined IPV6_V6ONLY
 	// Make NULL always bind to both IPv4 and IPv6, irrespectively of the order
 	// of results; only INADDR6_ANY seems to be affected by this
-	if (gai_iter->ai_family == AF_INET6)
+	if (ai->ai_family == AF_INET6)
 		soft_assert (setsockopt (fd, SOL_IPV6, IPV6_V6ONLY,
 			&yes, sizeof yes) != -1);
 #endif
 
-	char host[NI_MAXHOST], port[NI_MAXSERV];
-	host[0] = port[0] = '\0';
-	int err = getnameinfo (gai_iter->ai_addr, gai_iter->ai_addrlen,
-		host, sizeof host, port, sizeof port,
-		NI_NUMERICHOST | NI_NUMERICSERV);
-	if (err)
-		print_debug ("%s: %s", "getnameinfo", gai_strerror (err));
-
-	char *address = format_host_port_pair (host, port);
-	if (bind (fd, gai_iter->ai_addr, gai_iter->ai_addrlen))
+	char *address = gai_reconstruct_address (ai);
+	if (bind (fd, ai->ai_addr, ai->ai_addrlen))
 		print_error ("bind to %s failed: %s", address, strerror (errno));
 	else if (listen (fd, 16 /* arbitrary number */))
 		print_error ("listen on %s failed: %s", address, strerror (errno));
@@ -3865,12 +3850,12 @@ static void
 irc_listen_resolve (struct server_context *ctx,
 	const char *host, const char *port, struct addrinfo *gai_hints)
 {
-	struct addrinfo *gai_result, *gai_iter;
+	struct addrinfo *gai_result = NULL, *gai_iter = NULL;
 	int err = getaddrinfo (host, port, gai_hints, &gai_result);
 	if (err)
 	{
 		char *address = format_host_port_pair (host, port);
-		print_error ("bind to %s failed: %s: %s",
+		print_error ("binding to %s failed: %s: %s",
 			address, "getaddrinfo", gai_strerror (err));
 		free (address);
 		return;