gi-gio-2.0.38: Gio bindings

Copyright | Will Thompson and Iñaki García Etxebarria
License | LGPL-2.1
Maintainer | Iñaki García Etxebarria
Safe Haskell | None
Language | Haskell2010

GI.Gio.Objects.DebugControllerDBus

Contents

- Exported types
- Methods
  - new
  - stop
- Properties
  - connection
- Signals
  - authorize

Description

`GDebugControllerDBus` 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 `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 DebugController:debugEnabled and, by default, `logGetDebugEnabled`.

By default, no processes are allowed to call `SetDebugEnabled()` unless a DebugControllerDBus::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 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

Synopsis

- newtype DebugControllerDBus = DebugControllerDBus (ManagedPtr DebugControllerDBus)
- class (GObject o, IsDescendantOf DebugControllerDBus o) => IsDebugControllerDBus o
- toDebugControllerDBus :: (MonadIO m, IsDebugControllerDBus o) => o -> m DebugControllerDBus
- debugControllerDBusNew :: (HasCallStack, MonadIO m, IsDBusConnection a, IsCancellable b) => a -> Maybe b -> m (Maybe DebugControllerDBus)
- debugControllerDBusStop :: (HasCallStack, MonadIO m, IsDebugControllerDBus a) => a -> m ()
- constructDebugControllerDBusConnection :: (IsDebugControllerDBus o, MonadIO m, IsDBusConnection a) => a -> m (GValueConstruct o)
- getDebugControllerDBusConnection :: (MonadIO m, IsDebugControllerDBus o) => o -> m (Maybe DBusConnection)
- type DebugControllerDBusAuthorizeCallback = DBusMethodInvocation -> IO Bool
- afterDebugControllerDBusAuthorize :: (IsDebugControllerDBus a, MonadIO m) => a -> ((?self :: a) => DebugControllerDBusAuthorizeCallback) -> m SignalHandlerId
- onDebugControllerDBusAuthorize :: (IsDebugControllerDBus a, MonadIO m) => a -> ((?self :: a) => DebugControllerDBusAuthorizeCallback) -> m SignalHandlerId

# Exported types

newtype DebugControllerDBus Source #

Memory-managed wrapper type.

Constructors

DebugControllerDBus (ManagedPtr DebugControllerDBus) |

#### Instances

Instances details

Eq DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus Methods (==) :: DebugControllerDBus -> DebugControllerDBus -> Bool Source # (/=) :: DebugControllerDBus -> DebugControllerDBus -> Bool Source #
GObject DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus
ManagedPtrNewtype DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus Methods toManagedPtr :: DebugControllerDBus -> ManagedPtr DebugControllerDBus Source #
TypedObject DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus Methods glibType :: IO GType Source #
HasParentTypes DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus
IsGValue (Maybe DebugControllerDBus) Source # | Convert `DebugControllerDBus` to and from `GValue`. See `toGValue` and `fromGValue`.
Instance details Defined in GI.Gio.Objects.DebugControllerDBus Methods gvalueGType_ :: IO GType Source # gvalueSet_ :: Ptr GValue -> Maybe DebugControllerDBus -> IO () Source # gvalueGet_ :: Ptr GValue -> IO (Maybe DebugControllerDBus) Source #
type ParentTypes DebugControllerDBus Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus type ParentTypes DebugControllerDBus = '[Object, DebugController, Initable]

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

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

#### Instances

Instances details

(GObject o, IsDescendantOf DebugControllerDBus o) => IsDebugControllerDBus o Source # |
Instance details Defined in GI.Gio.Objects.DebugControllerDBus

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

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

Expand

#### 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 Source #

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 Source #

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) Source #

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) Source #

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

    get debugControllerDBus #connection

# Signals

## authorize

type DebugControllerDBusAuthorizeCallback Source #

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 Source #

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 Source #

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