/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2012 Red Hat, Inc.
 */

/*
 * This example monitors whether NM is running by checking if
 * "org.freedesktop.NetworkManager" is owned by a process on D-Bus.
 * It uses g_bus_watch_name().
 *
 * See also http://developer.gnome.org/gio/stable/gio-Watching-Bus-Names.html
 *
 * Standalone compilation:
 *   gcc -Wall monitor-nm-running-gdbus.c -o monitor-nm-running-gdbus `pkg-config --libs --cflags gio-2.0`
 */

#include <gio/gio.h>

static void
on_name_appeared(GDBusConnection *connection,
                 const char      *name,
                 const char      *name_owner,
                 gpointer         user_data)
{
    g_print("Name '%s' on the system bus is owned by %s => NM is running\n", name, name_owner);
}

static void
on_name_vanished(GDBusConnection *connection, const char *name, gpointer user_data)
{
    g_print("Name '%s' does not exist on the system bus => NM is not running\n", name);
}

int
main(int argc, char *argv[])
{
    guint                watcher_id;
    GMainLoop           *loop;
    GBusNameWatcherFlags flags;

    g_print("Monitor 'org.freedesktop.NetworkManager' D-Bus name\n");
    g_print("===================================================\n");

    flags = G_BUS_NAME_WATCHER_FLAGS_NONE;

    /* Start to watch "org.freedesktop.NetworkManager" bus name */
    watcher_id = g_bus_watch_name(G_BUS_TYPE_SYSTEM,
                                  "org.freedesktop.NetworkManager",
                                  flags,
                                  on_name_appeared,
                                  on_name_vanished,
                                  NULL,
                                  NULL);

    /* Run main loop */
    loop = g_main_loop_new(NULL, FALSE);
    g_main_loop_run(loop);

    /* Stop watching the name */
    g_bus_unwatch_name(watcher_id);

    return 0;
}