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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
“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
“debug-enabled” and, by default, g_log_get_debug_enabled().
default.
By default, all processes will be able to call SetDebugEnabled()
One option is to install a D-Bus security policy which restricts access to
SetDebugEnabled()$datadir/dbus-1/system.d/:
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<?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()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 “authorize” signal and query polkit in it:
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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); } |
GDebugControllerDBus * g_debug_controller_dbus_new (GDBusConnection *connection,GCancellable *cancellable,GError **error);
Create a new GDebugControllerDBus 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
GDebugControllerDBus is dropped.
Initialization may fail if registering the object on connection
fails.
connection |
a GDBusConnection to register the debug object on |
|
cancellable |
a GCancellable, or |
[nullable] |
error |
return location for a GError, or |
Since: 2.72
void
g_debug_controller_dbus_stop (GDebugControllerDBus *self);
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 “authorize” signals have been handled. This is expected to not take long, as it will just be waiting for threads to join. If any “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 GDebugControllerDBus 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 “authorize” signal handler will cause a deadlock and must not be done.
Since: 2.72
typedef struct _GDebugControllerDBus GDebugControllerDBus;
GDebugControllerDBus is an implementation of GDebugController over D-Bus.
Since: 2.72
“connection” property“connection” GDBusConnection *
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.
Owner: GDebugControllerDBus
Flags: Read / Write / Construct Only
Since: 2.72
“authorize” signalgboolean user_function (GDebugControllerDBus *controller, GDBusMethodInvocation *invocation, gpointer user_data)
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()
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.
controller |
The GDebugControllerDBus emitting the signal. |
|
invocation |
||
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 2.72