core: Introduce helper class to track connection keep alive

For P2P connections it makes sense to bind the connection to the status
of the operation that is being done. One example is that a wifi display
(miracast) P2P connection should be shut down when streaming fails for
some reason.

This new helper class allows binding a connection to the presence of a
DBus path meaning that it will be torn down if the process disappears.

1 files changed, 251 insertions, 0 deletions

diff --git a/src/nm-keep-alive.c b/src/nm-keep-alive.c
new file mode 100644
index 0000000000..be6dc2304b
--- /dev/null
+++ b/src/nm-keep-alive.c
@@ -0,0 +1,251 @@
+/*
+ * NetworkManager -- Inhibition management
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * Copyright 2018 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include "nm-keep-alive.h"
+#include "settings/nm-settings-connection.h"
+
+#include <string.h>
+
+/*****************************************************************************/
+
+NM_GOBJECT_PROPERTIES_DEFINE (NMKeepAlive,
+	PROP_ALIVE,
+);
+
+typedef struct {
+	gboolean floating;
+	gboolean forced;
+	NMSettingsConnection *connection;
+	GDBusConnection *dbus_connection;
+	char *dbus_client;
+
+	guint subscription_id;
+} NMKeepAlivePrivate;
+
+struct _NMKeepAlive {
+	GObject parent;
+	NMKeepAlivePrivate _priv;
+};
+
+struct _NMKeepAliveClass {
+	GObjectClass parent;
+};
+
+G_DEFINE_TYPE (NMKeepAlive, nm_keep_alive, G_TYPE_OBJECT)
+
+#define NM_KEEP_ALIVE_GET_PRIVATE(self) _NM_GET_PRIVATE (self, NMKeepAlive, NM_IS_KEEP_ALIVE)
+
+/*****************************************************************************/
+
+#define _NMLOG_DOMAIN      LOGD_CORE
+#define _NMLOG(level, ...) __NMLOG_DEFAULT (level, _NMLOG_DOMAIN, "keep-alive", __VA_ARGS__)
+
+/*****************************************************************************/
+
+NMKeepAlive* nm_keep_alive_new (gboolean floating)
+{
+	NMKeepAlive *res = g_object_new (NM_TYPE_KEEP_ALIVE, NULL);
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (res);
+
+	priv->floating = floating;
+
+	return res;
+}
+
+gboolean nm_keep_alive_is_alive (NMKeepAlive *self)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	if (priv->floating || priv->forced)
+		return TRUE;
+
+	if (priv->connection && NM_FLAGS_HAS (nm_settings_connection_get_flags (priv->connection),
+	                                      NM_SETTINGS_CONNECTION_INT_FLAGS_VISIBLE))
+		return TRUE;
+
+	if (priv->dbus_client)
+		return TRUE;
+
+	return FALSE;
+}
+
+void nm_keep_alive_sink (NMKeepAlive *self)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	priv->floating = FALSE;
+
+	_notify (self, PROP_ALIVE);
+}
+
+void nm_keep_alive_set_forced (NMKeepAlive *self, gboolean forced)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	priv->forced = forced;
+
+	_notify (self, PROP_ALIVE);
+}
+
+static void
+connection_flags_changed (NMSettingsConnection *connection,
+                          NMKeepAlive          *self)
+{
+	_notify (self, PROP_ALIVE);
+}
+
+
+void
+nm_keep_alive_set_settings_connection_watch_visible (NMKeepAlive         *self,
+                                                     NMSettingsConnection *connection)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	if (priv->connection) {
+		g_signal_handlers_disconnect_by_data (priv->connection, self);
+		priv->connection = NULL;
+	}
+
+	priv->connection = g_object_ref (connection);
+	g_signal_connect_object (priv->connection, NM_SETTINGS_CONNECTION_FLAGS_CHANGED,
+	                         G_CALLBACK (connection_flags_changed), self, 0);
+
+	_notify (self, PROP_ALIVE);
+}
+
+static void
+cleanup_dbus_watch (NMKeepAlive *self)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	_LOGD ("Cleanup DBus client watch");
+
+	g_clear_pointer (&priv->dbus_client, g_free);
+
+	if (priv->dbus_connection)
+		g_dbus_connection_signal_unsubscribe (priv->dbus_connection,
+		                                      priv->subscription_id);
+	g_clear_object (&priv->dbus_connection);
+}
+
+static void
+name_owner_changed_cb (GDBusConnection *connection,
+                       const char      *sender_name,
+                       const char      *object_path,
+                       const char      *interface_name,
+                       const char      *signal_name,
+                       GVariant        *parameters,
+                       gpointer         user_data)
+{
+	NMKeepAlive *self = NM_KEEP_ALIVE (user_data);
+
+	const char *old_owner;
+	const char *new_owner;
+
+	g_variant_get (parameters, "(&s&s&s)", NULL, &old_owner, &new_owner);
+
+	if (g_strcmp0 (new_owner, "") != 0)
+		return;
+
+	_LOGD ("DBus client for keep alive disappeared from bus");
+
+	cleanup_dbus_watch (self);
+
+	_notify (self, PROP_ALIVE);
+}
+
+void
+nm_keep_alive_set_dbus_client_watch (NMKeepAlive      *self,
+                                     GDBusConnection  *connection,
+                                     const char       *client_address,
+                                     GError          **error)
+{
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	cleanup_dbus_watch (self);
+
+	if (client_address == NULL)
+		return;
+
+	_LOGD ("Registering dbus client watch for keep alive");
+
+	priv->dbus_client = g_strdup (client_address);
+	priv->dbus_connection = g_object_ref (connection);
+	priv->subscription_id =
+		g_dbus_connection_signal_subscribe (connection, "org.freedesktop.DBus",
+		                                    "org.freedesktop.DBus", "NameOwnerChanged", "/org/freedesktop/DBus",
+		                                    priv->dbus_client, G_DBUS_SIGNAL_FLAGS_NONE,
+		                                    name_owner_changed_cb, self, NULL);
+}
+
+static void
+get_property (GObject *object,
+              guint prop_id,
+              GValue *value,
+              GParamSpec *pspec)
+{
+	NMKeepAlive *self = NM_KEEP_ALIVE (object);
+
+	switch (prop_id) {
+	case PROP_ALIVE:
+		g_value_set_boolean (value, nm_keep_alive_is_alive (self));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+nm_keep_alive_init (NMKeepAlive *self)
+{
+	/* Nothing to do */
+}
+
+static void
+dispose (GObject *object)
+{
+	NMKeepAlive *self = NM_KEEP_ALIVE (object);
+	NMKeepAlivePrivate *priv = NM_KEEP_ALIVE_GET_PRIVATE (self);
+
+	g_clear_object (&priv->connection);
+
+	cleanup_dbus_watch (self);
+}
+
+static void
+nm_keep_alive_class_init (NMKeepAliveClass *keep_alive_class)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS (keep_alive_class);
+
+	object_class->get_property = get_property;
+	object_class->dispose = dispose;
+
+	obj_properties[PROP_ALIVE] =
+	    g_param_spec_string (NM_KEEP_ALIVE_ALIVE, "", "",
+	                         NULL,
+	                         G_PARAM_READABLE |
+	                         G_PARAM_STATIC_STRINGS);
+
+	g_object_class_install_properties (object_class, _PROPERTY_ENUMS_LAST, obj_properties);
+}