daemon: Provide caller syncronization for quitting the daemon

Quit control messages are a bit strange because the daemon will quit
shortly afterwards.  There are three syncronization issues here.

1. We need the response to be written right away, because if
   we wait for the main loop it might not be written.
2. Callers may want to wait for the daemon to exit, so keep the
   socket open until we do.
3. Prevent additional connections on the control socket.

4 files changed, 39 insertions, 13 deletions

diff --git a/daemon/control/gkd-control-client.c b/daemon/control/gkd-control-client.c
index e7446179..ecfdc5ca 100644
--- a/daemon/control/gkd-control-client.c
+++ b/daemon/control/gkd-control-client.c
@@ -181,6 +181,11 @@ control_chat (const gchar *directory,
 		return FALSE;
 
 	ret = control_write (sock, buffer) && control_read (sock, buffer);
+
+	if (flags & GKD_CONTROL_WAIT_FOR_CLOSE) {
+		while (read (sock, &path, sizeof (path)) < 0);
+	}
+
 	close (sock);
 	return ret;
 }
diff --git a/daemon/control/gkd-control-server.c b/daemon/control/gkd-control-server.c
index 5a81eb49..65a1b042 100644
--- a/daemon/control/gkd-control-server.c
+++ b/daemon/control/gkd-control-server.c
@@ -48,6 +48,8 @@ typedef struct _ControlData {
 
 EGG_SECURE_DECLARE (control_server);
 
+static gchar *control_path;
+
 /* -----------------------------------------------------------------------------------
  * CONTROL SERVER
  */
@@ -242,11 +244,24 @@ control_process (EggBuffer *req, GIOChannel *channel)
 		g_return_if_fail (!egg_buffer_has_error (&cdata->buffer));
 		egg_buffer_set_uint32 (&cdata->buffer, 0, cdata->buffer.len);
 
-		/* Can't send response in main loop, send here */
+		/*
+		 * Quit messages are a bit strange because the daemon will quit.
+		 * There are three syncronization issues here.
+		 * 1. We need the response to be written right away, because if
+		 *    we wait for the main loop it might not be written.
+		 * 2. Callers may want to wait for the daemon to exit, so keep the
+		 *    socket open until we do.
+		 * 3. Prevent additional connections on the control socket (done via
+		 *    gkd_control_stop()).
+		 */
 		if (op == GKD_CONTROL_OP_QUIT) {
 			if (write (g_io_channel_unix_get_fd (channel),
 			           cdata->buffer.buf, cdata->buffer.len) != cdata->buffer.len)
 				g_message ("couldn't write response to close control request");
+			if (res == GKD_CONTROL_RESULT_OK) {
+				egg_cleanup_register ((GDestroyNotify)g_io_channel_unref,
+				                      g_io_channel_ref (channel));
+			}
 			control_data_free (cdata);
 
 		/* Any other response, send in the main loop */
@@ -373,12 +388,14 @@ control_accept (GIOChannel *channel, GIOCondition cond, gpointer callback_data)
 	return TRUE;
 }
 
-static void
-control_cleanup_channel (gpointer user_data)
+void
+gkd_control_stop (void)
 {
-	gchar *path = user_data;
-	unlink (path);
-	g_free (path);
+	if (control_path) {
+		unlink (control_path);
+		g_free (control_path);
+		control_path = NULL;
+	}
 }
 
 gboolean
@@ -386,13 +403,12 @@ gkd_control_listen (void)
 {
 	struct sockaddr_un addr;
 	GIOChannel *channel;
-	gchar *path;
 	int sock;
 
-	path = g_strdup_printf ("%s/control", gkd_util_get_master_directory ());
-	egg_cleanup_register (control_cleanup_channel, path);
+	control_path = g_strdup_printf ("%s/control", gkd_util_get_master_directory ());
+	egg_cleanup_register ((GDestroyNotify)gkd_control_stop, NULL);
 
-	unlink (path);
+	unlink (control_path);
 
 	sock = socket (AF_UNIX, SOCK_STREAM, 0);
 	if (sock < 0) {
@@ -402,15 +418,15 @@ gkd_control_listen (void)
 
 	memset (&addr, 0, sizeof (addr));
 	addr.sun_family = AF_UNIX;
-	g_strlcpy (addr.sun_path, path, sizeof (addr.sun_path));
+	g_strlcpy (addr.sun_path, control_path, sizeof (addr.sun_path));
 	if (bind (sock, (struct sockaddr*) &addr, sizeof (addr)) < 0) {
-		g_warning ("couldn't bind to control socket: %s: %s", path, g_strerror (errno));
+		g_warning ("couldn't bind to control socket: %s: %s", control_path, g_strerror (errno));
 		close (sock);
 		return FALSE;
 	}
 
 	if (listen (sock, 128) < 0) {
-		g_warning ("couldn't listen on control socket: %s: %s", path, g_strerror (errno));
+		g_warning ("couldn't listen on control socket: %s: %s", control_path, g_strerror (errno));
 		close (sock);
 		return FALSE;
 	}
diff --git a/daemon/control/gkd-control.h b/daemon/control/gkd-control.h
index c6d31aa7..53af2c6e 100644
--- a/daemon/control/gkd-control.h
+++ b/daemon/control/gkd-control.h
@@ -25,10 +25,13 @@
 
 typedef enum {
 	GKD_CONTROL_QUIET_IF_NO_PEER = 1 << 0,
+	GKD_CONTROL_WAIT_FOR_CLOSE = 1 << 1,
 } GkdControlFlags;
 
 gboolean          gkd_control_listen        (void);
 
+void              gkd_control_stop          (void);
+
 gchar**           gkd_control_initialize    (const gchar *directory,
                                              const gchar *components,
                                              const gchar **env);
diff --git a/daemon/gkd-main.c b/daemon/gkd-main.c
index 5c5381c7..2bcfc045 100644
--- a/daemon/gkd-main.c
+++ b/daemon/gkd-main.c
@@ -399,6 +399,8 @@ dump_diagnostics (void)
 void
 gkd_main_quit (void)
 {
+	/* Always stop accepting control connections immediately */
+	gkd_control_stop ();
 	g_main_loop_quit (loop);
 }