GI.Gio.Objects.DebugControllerDBus

DebugControllerDBus is an implementation of DebugController which exposes debug settings as a D-Bus object.

It is a Initable object, and will register an object at /org/gtk/Debugging on the bus given as DebugControllerDBus:connection once it’s initialized. The object will be unregistered when the last reference to the DebugControllerDBus 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 DebugController:debug-enabled and, by default, logGetDebugEnabled. default.

By default, all processes will be able to call SetDebugEnabled(). If this process is 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 code

<?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 DebugControllerDBus::authorize signal and query polkit in it:

C code

 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);
 }

Since: 2.72

Exported types

newtype DebugControllerDBus

Memory-managed wrapper type.

Constructors

DebugControllerDBus (ManagedPtr DebugControllerDBus)

Instances

Eq DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

Methods

(==) :: DebugControllerDBus -> DebugControllerDBus -> Bool

(/=) :: DebugControllerDBus -> DebugControllerDBus -> Bool

GObject DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

ManagedPtrNewtype DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

Methods

toManagedPtr :: DebugControllerDBus -> ManagedPtr DebugControllerDBus

TypedObject DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

Methods

glibType :: IO GType

HasParentTypes DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

IsGValue (Maybe DebugControllerDBus)

Convert DebugControllerDBus to and from GValue. See toGValue and fromGValue.

Defined in GI.Gio.Objects.DebugControllerDBus

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe DebugControllerDBus -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe DebugControllerDBus)

type ParentTypes DebugControllerDBus

Defined in GI.Gio.Objects.DebugControllerDBus

type ParentTypes DebugControllerDBus = '[Object, DebugController, Initable]

class (GObject o, IsDescendantOf DebugControllerDBus o) => IsDebugControllerDBus o

Type class for types which can be safely cast to DebugControllerDBus, for instance with toDebugControllerDBus.

Instances

(GObject o, IsDescendantOf DebugControllerDBus o) => IsDebugControllerDBus o

Defined in GI.Gio.Objects.DebugControllerDBus

toDebugControllerDBus :: (MonadIO m, IsDebugControllerDBus o) => o -> m DebugControllerDBus

Cast to DebugControllerDBus, for types for which this is known to be safe. For general casts, use castTo.

Methods

Click to display all available methods, including inherited ones

Methods

bindProperty, bindPropertyFull, forceFloating, freezeNotify, getv, init, isFloating, notify, notifyByPspec, ref, refSink, runDispose, stealData, stealQdata, stop, thawNotify, unref, watchClosure.

Getters

getData, getDebugEnabled, getProperty, getQdata.

Setters

setData, setDataFull, setDebugEnabled, setProperty.

new

debugControllerDBusNew

Arguments

:: (HasCallStack, MonadIO m, IsDBusConnection a, IsCancellable b)

=> a

connection: a DBusConnection to register the debug object on

-> Maybe b

cancellable: a Cancellable, or Nothing

-> m (Maybe DebugControllerDBus)

Returns: a new DebugControllerDBus, or Nothing on failure (Can throw GError)

Create a new DebugControllerDBus and synchronously initialize it.

Initializing the object will export the debug object on connection. The object will remain registered until the last reference to the DebugControllerDBus is dropped.

Initialization may fail if registering the object on connection fails.

Since: 2.72

stop

debugControllerDBusStop

Arguments

:: (HasCallStack, MonadIO m, IsDebugControllerDBus a)

=> a

self: a DebugControllerDBus

-> m ()

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

Any pending method calls to the object will complete successfully, but new ones will return an error. This method will block until all pending DebugControllerDBus::authorize signals have been handled. This is expected to not take long, as it will just be waiting for threads to join. If any DebugControllerDBus::authorize signal handlers are still executing in other threads, this will block until after they have returned.

This method will be called automatically when the final reference to the DebugControllerDBus is dropped. You may want to call it explicitly to know when the controller has been fully removed from the bus, or to break reference count cycles.

Calling this method from within a DebugControllerDBus::authorize signal handler will cause a deadlock and must not be done.

Since: 2.72

Properties

connection

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

Typically this will be the same connection (to the system or session bus) which the rest of the application or service’s D-Bus objects are registered on.

Since: 2.72

constructDebugControllerDBusConnection :: (IsDebugControllerDBus o, MonadIO m, IsDBusConnection a) => a -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “connection” property. This is rarely needed directly, but it is used by new.

getDebugControllerDBusConnection :: (MonadIO m, IsDebugControllerDBus o) => o -> m (Maybe DBusConnection)

Get the value of the “connection” property. When overloading is enabled, this is equivalent to

get debugControllerDBus #connection

Signals

authorize

type DebugControllerDBusAuthorizeCallback

Arguments

 = DBusMethodInvocation

invocation: A DBusMethodInvocation.

-> IO Bool

Returns: True if the call is authorized, False otherwise.

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

This signal is emitted in a dedicated worker thread, so handlers are allowed to perform blocking I/O. This means that, for example, it is appropriate to call polkit_authority_check_authorization_sync() to check authorization using polkit.

If False is returned then no further handlers are run and the request to change the debug settings is rejected.

Otherwise, if True is returned, signal emission continues. If no handlers return False, then the debug settings are allowed to be changed.

Signal handlers must not modify invocation, or cause it to return a value.

The default class handler just returns True.

Since: 2.72

afterDebugControllerDBusAuthorize :: (IsDebugControllerDBus a, MonadIO m) => a -> ((?self :: a) => DebugControllerDBusAuthorizeCallback) -> m SignalHandlerId

Connect a signal handler for the authorize signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after debugControllerDBus #authorize callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onDebugControllerDBusAuthorize :: (IsDebugControllerDBus a, MonadIO m) => a -> ((?self :: a) => DebugControllerDBusAuthorizeCallback) -> m SignalHandlerId

Connect a signal handler for the authorize signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on debugControllerDBus #authorize callback