dns/resolved: various fixesth/systemd-resolved-bgo762540

- mode in init_resolv_conf_mode() must be initialized in
  case it is NULL.
- drop the NULL sentinal from resolved_paths and make it
  static.
- resolved_proxy_created() must handle the fact that @self
  might be already destroyed.
- call_done() must not access @self before ensuring that
  the call was not cancelled.
  What's more, send_update() can be called by resolved_proxy_created(),
  thus it must ensure that it has an @update_cancellable. Let
  send_update() create and cancel the @update_cancellable().
  Also, send_update() -- which now manages @update_cancellable
  instead of update() -- must actually cancel the previous
  cancellable, otherwise the callback again might access
  a disposed @self.

2 files changed, 21 insertions, 16 deletions

diff --git a/src/dns-manager/nm-dns-manager.c b/src/dns-manager/nm-dns-manager.c
index f4f0dc97d7..f6f6faa52b 100644
--- a/src/dns-manager/nm-dns-manager.c
+++ b/src/dns-manager/nm-dns-manager.c
@@ -1603,15 +1603,14 @@ NM_DEFINE_SINGLETON_GETTER (NMDnsManager, nm_dns_manager_get, NM_TYPE_DNS_MANAGE
 static gboolean
 _resolvconf_resolved_managed (void)
 {
-	GFile *f;
-	GFileInfo *info;
-	gboolean ret = FALSE;
-	const gchar *resolved_paths[] = {
+	static const char *const resolved_paths[] = {
 		"/run/systemd/resolve/resolv.conf",
 		"/lib/systemd/resolv.conf",
 		"/usr/lib/systemd/resolv.conf",
-		NULL
 	};
+	GFile *f;
+	GFileInfo *info;
+	gboolean ret = FALSE;
 
 	f = g_file_new_for_path (_PATH_RESCONF);
 	info = g_file_query_info (f,
@@ -1685,6 +1684,7 @@ again:
 			priv->plugin = nm_dns_systemd_resolved_new ();
 			plugin_changed = TRUE;
 		}
+		mode = "systemd-resolved";
 	} else if (nm_streq0 (mode, "dnsmasq")) {
 		if (force_reload_plugin || !NM_IS_DNS_DNSMASQ (priv->plugin)) {
 			_clear_plugin (self);
diff --git a/src/dns-manager/nm-dns-systemd-resolved.c b/src/dns-manager/nm-dns-systemd-resolved.c
index f53520d7e1..a85d3df8ec 100644
--- a/src/dns-manager/nm-dns-systemd-resolved.c
+++ b/src/dns-manager/nm-dns-systemd-resolved.c
@@ -83,7 +83,7 @@ call_done (GObject *source, GAsyncResult *r, gpointer user_data)
 {
 	GVariant *v;
 	GError *error = NULL;
-	NMDnsSystemdResolved *self = NM_DNS_SYSTEMD_RESOLVED (user_data);
+	NMDnsSystemdResolved *self = (NMDnsSystemdResolved *) user_data;
 
 	v = g_dbus_proxy_call_finish (G_DBUS_PROXY (source), r, &error);
 
@@ -251,9 +251,13 @@ send_updates (NMDnsSystemdResolved *self)
 	NMDnsSystemdResolvedPrivate *priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE (self);
 	GVariant *v;
 
+	nm_clear_g_cancellable (&priv->update_cancellable);
+
 	if (!priv->resolve)
 		return;
 
+	priv->update_cancellable = g_cancellable_new ();
+
 	while ((v = g_queue_pop_head (&priv->dns_updates)) != NULL) {
 		g_dbus_proxy_call (priv->resolve, "SetLinkDNS", v,
 		                   G_DBUS_CALL_FLAGS_NONE,
@@ -276,7 +280,6 @@ update (NMDnsPlugin *plugin,
         const char *hostname)
 {
 	NMDnsSystemdResolved *self = NM_DNS_SYSTEMD_RESOLVED (plugin);
-	NMDnsSystemdResolvedPrivate *priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE (self);
 	GArray *interfaces = g_array_new (TRUE, TRUE, sizeof (InterfaceConfig));
 	const NMDnsIPConfigData **c;
 	int i;
@@ -285,9 +288,6 @@ update (NMDnsPlugin *plugin,
 		add_interface_configuration (self, interfaces, *c);
 
 	free_pending_updates (self);
-	g_clear_object (&priv->update_cancellable);
-
-	priv->update_cancellable = g_cancellable_new ();
 
 	for (i = 0; i < interfaces->len; i++) {
 		InterfaceConfig *ic = &g_array_index (interfaces, InterfaceConfig, i);
@@ -328,21 +328,26 @@ nm_dns_systemd_resolved_new (void)
 static void
 resolved_proxy_created (GObject *source, GAsyncResult *r, gpointer user_data)
 {
-	NMDnsSystemdResolved *self = NM_DNS_SYSTEMD_RESOLVED (user_data);
-	NMDnsSystemdResolvedPrivate *priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE (self);
+	NMDnsSystemdResolved *self = (NMDnsSystemdResolved *) user_data;
+	NMDnsSystemdResolvedPrivate *priv;
 	GError *error = NULL;
+	GDBusProxy *resolve;
 
-	g_clear_object (&priv->init_cancellable);
-
-	priv->resolve = g_dbus_proxy_new_finish (r, &error);
+	resolve = g_dbus_proxy_new_finish (r, &error);
+	if (   !resolve
+	    && g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+		return;
 
-	if (priv->resolve == NULL) {
+	priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE (self);
+	g_clear_object (&priv->init_cancellable);
+	if (!priv->resolve) {
 		_LOGW ("failed to connect to resolved via DBus: %s", error->message);
 		g_signal_emit_by_name (self, NM_DNS_PLUGIN_FAILED);
 		g_error_free (error);
 		return;
 	}
 
+	priv->resolve = resolve;
 	send_updates (self);
 }