config: add support for reloading of configuration

No actual reloading is yet implemented. Later we will decide
on specific configuration parameters where we support reloading.
They must be then implemented one-by-one.

Some configuration parameters can be set via command line.
If a parameter is set from command line, the original value
from command line will still be preserved after reloading.

(cherry picked from commit 82cfd5ad47)

src/main.c

@@ -211,7 +211,14 @@ _init_nm_debug (const char *debug)
 void
 nm_main_config_reload ()
 {
-	nm_log_info (LOGD_CORE, "reloading configuration not supported.");
+	nm_log_info (LOGD_CORE, "reload configuration...");
+	/* The signal handler thread is only installed after
+	 * creating NMConfig instance, and on shut down we
+	 * no longer run the mainloop (to reach this point).
+	 *
+	 * Hence, a NMConfig singleton instance must always be
+	 * available. */
+	nm_config_reload (nm_config_get ());
 }
 
 static void

src/nm-config.c

@@ -29,6 +29,7 @@
 #include "nm-utils.h"
 #include "nm-glib-compat.h"
 #include "nm-device.h"
+#include "NetworkManagerUtils.h"
 
 #include <gio/gio.h>
 #include <glib/gi18n.h>
@@ -81,6 +82,14 @@ typedef struct {
 	gboolean configure_and_quit;
 } NMConfigPrivate;
 
+enum {
+	SIGNAL_CONFIG_CHANGED,
+
+	LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
 G_DEFINE_TYPE (NMConfig, nm_config, G_TYPE_OBJECT)
 
 #define NM_CONFIG_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NM_TYPE_CONFIG, NMConfigPrivate))
@@ -553,6 +562,59 @@ find_base_config (NMConfig *config, GError **error)
 
 /************************************************************************/
 
+void
+nm_config_reload (NMConfig *self)
+{
+	NMConfigPrivate *priv;
+	NMConfig *new;
+	GError *error = NULL;
+	GHashTable *changes;
+	NMConfigData *old_data;
+	NMConfigData *new_data = NULL;
+
+	g_return_if_fail (NM_IS_CONFIG (self));
+
+	priv = NM_CONFIG_GET_PRIVATE (self);
+
+	/* pass on the original command line options. This means, that
+	 * options specified at command line cannot ever be reloaded from
+	 * file. That seems desirable.
+	 */
+	new = nm_config_new (&priv->cli, &error);
+
+	if (!new) {
+		nm_log_err (LOGD_CORE, "Failed to reload the configuration: %s", error->message);
+		g_clear_error (&error);
+		return;
+	}
+
+	old_data = priv->config_data;
+	new_data = nm_config_get_data (new);
+
+	changes = g_hash_table_new (g_str_hash, g_str_equal);
+
+	/* reloading configuration means we have to carefully check every single option
+	 * that we want to support and take specific actions. */
+
+	/* FIXME: no actual reloading implemented yet */
+
+	if (g_hash_table_size (changes))
+		new_data = g_object_ref (new_data);
+	else
+		new_data = NULL;
+
+	g_object_unref (new);
+
+	if (new_data) {
+		old_data = priv->config_data;
+		priv->config_data = new_data;
+		g_signal_emit (self, signals[SIGNAL_CONFIG_CHANGED], 0, new_data, changes, old_data);
+		g_object_unref (old_data);
+	}
+
+	g_hash_table_destroy (changes);
+}
+
 NM_DEFINE_SINGLETON_DESTRUCTOR (NMConfig);
 NM_DEFINE_SINGLETON_WEAK_REF (NMConfig);
 
@@ -753,5 +815,13 @@ nm_config_class_init (NMConfigClass *config_class)
 
 	g_type_class_add_private (config_class, sizeof (NMConfigPrivate));
 	object_class->finalize = finalize;
+
+	signals[SIGNAL_CONFIG_CHANGED] =
+	    g_signal_new (NM_CONFIG_SIGNAL_CONFIG_CHANGED,
+	                  G_OBJECT_CLASS_TYPE (object_class),
+	                  G_SIGNAL_RUN_FIRST,
+	                  G_STRUCT_OFFSET (NMConfigClass, config_changed),
+	                  NULL, NULL, NULL,
+	                  G_TYPE_NONE, 3, NM_TYPE_CONFIG_DATA, G_TYPE_HASH_TABLE, NM_TYPE_CONFIG_DATA);
 }
 

src/nm-config.h

@@ -37,6 +37,9 @@ G_BEGIN_DECLS
 #define NM_IS_CONFIG_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass),  NM_TYPE_CONFIG))
 #define NM_CONFIG_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),  NM_TYPE_CONFIG, NMConfigClass))
 
+/* Signals */
+#define NM_CONFIG_SIGNAL_CONFIG_CHANGED             "config-changed"
+
 typedef struct NMConfigCmdLineOptions NMConfigCmdLineOptions;
 
 struct _NMConfig {
@@ -45,6 +48,9 @@ struct _NMConfig {
 
 typedef struct {
 	GObjectClass parent;
+
+	/* Signals */
+	void (*config_changed) (NMConfig *config, GHashTable *changes, NMConfigData *old_data);
 } NMConfigClass;
 
 GType nm_config_get_type (void);
@@ -80,6 +86,7 @@ void                    nm_config_cmd_line_options_add_to_entries (NMConfigCmdLi
 
 NMConfig *nm_config_new (const NMConfigCmdLineOptions *cli, GError **error);
 NMConfig *nm_config_setup (const NMConfigCmdLineOptions *cli, GError **error);
+void nm_config_reload (NMConfig *config);
 
 G_END_DECLS