Added dummy control socket answering / changed serve_accept_loop to use

select() to avoid a separate listening thread.

serve.c

@@ -342,7 +342,7 @@ void serve_open_control_socket(struct mode_serve_params* params)
 	if (!params->control_socket_name)
 		return;
 
-	params->control = socket(AF_UNIX, SOCK_DGRAM, 0);
+	params->control = socket(AF_UNIX, SOCK_STREAM, 0);
 	SERVER_ERROR_ON_FAILURE(params->control,
 	  "Couldn't create control socket");
 	
@@ -350,35 +350,34 @@ void serve_open_control_socket(struct mode_serve_params* params)
 	bind_address.sun_family = AF_UNIX;
 	strcpy(bind_address.sun_path, params->control_socket_name);
 	
+	unlink(params->control_socket_name); /* ignore failure */
+	
 	SERVER_ERROR_ON_FAILURE(
 		bind(params->control, &bind_address, sizeof(bind_address)),
 		"Couldn't bind control socket to %s",
 		params->control_socket_name
 	);
+	
+	SERVER_ERROR_ON_FAILURE(
+		listen(params->control, 5),
+		"Couldn't listen on control socket"
+	);
 }
 
-void serve_accept_loop(struct mode_serve_params* params) 
+void accept_nbd_client(struct mode_serve_params* params, int client_fd, struct sockaddr* client_address)
 {
-	while (1) {
 	pthread_t             client_thread;
-		struct sockaddr client_address;
 	struct client_params* client_params;
-		socklen_t socket_length=0;
-		
-		int client_socket = accept(params->server, &client_address, 
-		  &socket_length);
-		  
-		SERVER_ERROR_ON_FAILURE(client_socket, "accept() failed");
 	
 	if (params->acl && 
-		    !is_included_in_acl(params->acl_entries, params->acl, &client_address)) {
+	    !is_included_in_acl(params->acl_entries, params->acl, client_address)) {
-			write(client_socket, "Access control error", 20);
+		write(client_fd, "Access control error", 20);
-			close(client_socket);
+		close(client_fd);
-			continue;
+		return;
 	}
 	
 	client_params = xmalloc(sizeof(struct client_params));
-		client_params->socket = client_socket;
+	client_params->socket = client_fd;
 	client_params->filename = params->filename;
 	client_params->block_allocation_map = 
 	  params->block_allocation_map;
@@ -390,6 +389,40 @@ void serve_accept_loop(struct mode_serve_params* params)
 	/* FIXME: keep track of them? */
 	/* FIXME: maybe shouldn't be fatal? */
 }
+
+void accept_control_connection(struct mode_serve_params* params, int client_fd, struct sockaddr* client_address)
+{
+	write(client_fd, "hello", 5);
+	close(client_fd);
+}
+
+void serve_accept_loop(struct mode_serve_params* params) 
+{
+	while (1) {
+		int             activity_fd, client_fd;
+		struct sockaddr client_address;
+		fd_set          fds;
+		socklen_t       socklen=0;
+		
+		FD_ZERO(&fds);
+		FD_SET(params->server, &fds);
+		FD_SET(params->control, &fds);
+		
+		SERVER_ERROR_ON_FAILURE(
+			select(FD_SETSIZE, &fds, NULL, NULL, NULL),
+			"select() failed"
+		);
+		
+		activity_fd = FD_ISSET(params->server, &fds) ? params->server : 
+		  params->control;
+		client_fd = accept(activity_fd, &client_address, &socklen);
+		SERVER_ERROR_ON_FAILURE(client_fd, "accept() failed");
+		
+		if (activity_fd == params->server)
+			accept_nbd_client(params, client_fd, &client_address);
+		if (activity_fd == params->control)
+			accept_control_connection(params, client_fd, &client_address);
+	}
 }
 
 void serve_init_allocation_map(struct mode_serve_params* params)