Gio.DebugControllerDBus
Description: Reference for Gio.DebugControllerDBus

### Class

# GioDebugControllerDBus

since: 2.72

#### Description [src]

    class Gio.DebugControllerDBus : GObject.Object
      implements Gio.DebugController, Gio.Initable {
      /* No available fields */
    }

`GDebugControllerDBus` is an implementation of `GDebugController` which exposes debug settings as a D-Bus object.

It is a `GInitable` object, and will register an object at `/org/gtk/Debugging` on the bus given as `GDebugControllerDBus:connection` once it’s initialized. The object will be unregistered when the last reference to the `GDebugControllerDBus` is dropped.

This D-Bus object can be used by remote processes to enable or disable debug output in this process. Remote processes calling `org.gtk.Debugging.SetDebugEnabled()` will affect the value of `GDebugController:debug-enabled` and, by default, `g_log_get_debug_enabled()`.

By default, no processes are allowed to call `SetDebugEnabled()` unless a `GDebugControllerDBus::authorize` signal handler is installed. This is because the process may be privileged, or might expose sensitive information in its debug output. You may want to restrict the ability to enable debug output to privileged users or processes.

One option is to install a D-Bus security policy which restricts access to `SetDebugEnabled()`, installing something like the following in `$datadir/dbus-1/system.d/`:

    <?xml version="1.0"?> <!--*-nxml-*-->
    <!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
         "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
    <busconfig>
      <policy user="root">
        <allow send_destination="com.example.MyService" send_interface="org.gtk.Debugging"/>
      </policy>
      <policy context="default">
        <deny send_destination="com.example.MyService" send_interface="org.gtk.Debugging"/>
      </policy>
    </busconfig>

This will prevent the `SetDebugEnabled()` method from being called by all except root. It will not prevent the `DebugEnabled` property from being read, as it’s accessed through the `org.freedesktop.DBus.Properties` interface.

Another option is to use polkit to allow or deny requests on a case-by-case basis, allowing for the possibility of dynamic authorisation. To do this, connect to the `GDebugControllerDBus::authorize` signal and query polkit in it:

      g_autoptr(GError) child_error = NULL;
      g_autoptr(GDBusConnection) connection = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, NULL);
      gulong debug_controller_authorize_id = 0;

      // Set up the debug controller.
      debug_controller = G_DEBUG_CONTROLLER (g_debug_controller_dbus_new (priv->connection, NULL, &child_error));
      if (debug_controller == NULL)
        {
          g_error ("Could not register debug controller on bus: %s",
                   child_error->message);
        }

      debug_controller_authorize_id = g_signal_connect (debug_controller,
                                                        "authorize",
                                                        G_CALLBACK (debug_controller_authorize_cb),
                                                        self);

      static gboolean
      debug_controller_authorize_cb (GDebugControllerDBus  *debug_controller,
                                     GDBusMethodInvocation *invocation,
                                     gpointer               user_data)
      {
        g_autoptr(PolkitAuthority) authority = NULL;
        g_autoptr(PolkitSubject) subject = NULL;
        g_autoptr(PolkitAuthorizationResult) auth_result = NULL;
        g_autoptr(GError) local_error = NULL;
        GDBusMessage *message;
        GDBusMessageFlags message_flags;
        PolkitCheckAuthorizationFlags flags = POLKIT_CHECK_AUTHORIZATION_FLAGS_NONE;

        message = g_dbus_method_invocation_get_message (invocation);
        message_flags = g_dbus_message_get_flags (message);

        authority = polkit_authority_get_sync (NULL, &local_error);
        if (authority == NULL)
          {
            g_warning ("Failed to get polkit authority: %s", local_error->message);
            return FALSE;
          }

        if (message_flags & G_DBUS_MESSAGE_FLAGS_ALLOW_INTERACTIVE_AUTHORIZATION)
          flags |= POLKIT_CHECK_AUTHORIZATION_FLAGS_ALLOW_USER_INTERACTION;

        subject = polkit_system_bus_name_new (g_dbus_method_invocation_get_sender (invocation));

        auth_result = polkit_authority_check_authorization_sync (authority,
                                                                 subject,
                                                                 "com.example.MyService.set-debug-enabled",
                                                                 NULL,
                                                                 flags,
                                                                 NULL,
                                                                 &local_error);
        if (auth_result == NULL)
          {
            g_warning ("Failed to get check polkit authorization: %s", local_error->message);
            return FALSE;
          }

        return polkit_authorization_result_get_is_authorized (auth_result);
      }

Available since: 2.72

#### Hierarchy

#### Ancestors

- GObject

#### Implements

- GDebugController
- GInitable

#### Constructors

###### g_debug_controller_dbus_new

Create a new `GDebugControllerDBus` and synchronously initialize it.

since: 2.72

#### Instance methods

###### g_debug_controller_dbus_stop

Stop the debug controller, unregistering its object from the bus.

since: 2.72

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GDebugController (2)

###### g_debug_controller_get_debug_enabled

Get the value of `GDebugController:debug-enabled`.

since: 2.72

###### g_debug_controller_set_debug_enabled

Set the value of `GDebugController:debug-enabled`.

since: 2.72

##### Methods inherited from GInitable (1)

###### g_initable_init

Initializes the object implementing the interface.

since: 2.22

#### Properties

###### Gio.DebugControllerDBus:connection

The D-Bus connection to expose the debugging interface on.

since: 2.72

##### Properties inherited from GDebugController (1)

###### GDebugController:debug-enabled

`TRUE` if debug output should be exposed (for example by forwarding it to the journal), `FALSE` otherwise.

since: 2.72

#### Signals

###### Gio.DebugControllerDBus::authorize

Emitted when a D-Bus peer is trying to change the debug settings and used to determine if that is authorized.

since: 2.72

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

#### Class structure

    struct GioDebugControllerDBusClass {
      GObjectClass parent_class;
      gboolean (* authorize) (
        GDebugControllerDBus* controller,
        GDBusMethodInvocation* invocation
      );
      None padding;

    }

The virtual function table for `GDebugControllerDBus`.

###### Class members

`parent_class: GObjectClass`

  The parent class.

`authorize: gboolean (* authorize) ( GDebugControllerDBus* controller, GDBusMethodInvocation* invocation )`

  Default handler for the `GDebugControllerDBus::authorize` signal.

`padding: None`

  No description available.

#### Virtual methods

###### Gio.DebugControllerDBusClass.authorize

Default handler for the `GDebugControllerDBus::authorize` signal.