// OpenVPN 3 Linux client -- Next generation OpenVPN client // // SPDX-License-Identifier: AGPL-3.0-only // // Copyright (C) 2017 - 2023 OpenVPN Inc // Copyright (C) 2017 - 2023 David Sommerseth // #pragma once #include #include "idlecheck.hpp" #include "exceptions.hpp" /** * DBusObject is the object which carries data, methods * and signals to be provided over the D-Bus. * * Each DBusObject must have a unique object path * and the introspection XML describes what this object * contains. * * The callback methods are called by the D-Bus framework * and happens each time a client tries to do something * with this object over D-Bus * * The design idea with DBusObject is that it is primarily * the D-Bus bus which owns and have the reference to a * DBusObject instance. So when a DBusObject is to be * removed that should happen through deleting the object * via the GDBus API and not by just deleting the object * instance directly in C++. This ensures that the object * is not seen as available on any of the busses in D-Bus. * * This DBusObject class is intended to be inheritted by * a child class and only to implement the really needed * virtual methods below. * */ class DBusObject { public: DBusObject(std::string obj_path, std::string introspection_xml) : registered(false), object_path(obj_path), object_id(0), idle_checker(nullptr) { ParseIntrospectionXML(introspection_xml); } DBusObject(std::string obj_path) : registered(false), object_path(obj_path), object_id(0), idle_checker(nullptr), introspection(nullptr) { } virtual ~DBusObject() { if (introspection) { g_dbus_node_info_unref(introspection); } } guint GetObjectId() const { if (!registered) { THROW_DBUSEXCEPTION("DBusObject", "Object have not been registered to D-Bus yet"); } return object_id; } std::string GetObjectPath() const { return object_path; } void RegisterObject(GDBusConnection *dbuscon) { if (registered) { THROW_DBUSEXCEPTION("DBusObject", "Object is already registered in D-Bus"); } if (nullptr == introspection) { THROW_DBUSEXCEPTION("DBusObject", "No introspection document parsed"); } GError *error = NULL; object_id = g_dbus_connection_register_object(dbuscon, object_path.c_str(), introspection->interfaces[0], &dbusobj_interface_vtable, this, NULL, // destruct function &error); if (object_id < 1) { std::stringstream err; err << "RegisterObject(" + object_path + ") failed: "; err << (error != NULL ? error->message : "(unknown)"); THROW_DBUSEXCEPTION("DBusObject", err.str()); } registered = true; } /** * Sets/registers an IdleChecker object for this DBusObject * * @@param chk A valid pointer to an IdleCheck object */ void IdleCheck_Register(IdleCheck *chk) { idle_checker = chk; } void RemoveObject(GDBusConnection *dbuscon) { if (!registered) { THROW_DBUSEXCEPTION("DBusObject", "Object have not been registered to D-Bus yet"); } registered = false; GError *err = nullptr; if (!g_dbus_connection_flush_sync(dbuscon, NULL, &err)) { std::cout << "** ERROR ** Connection flush failed when " << "removing object [" << introspection->interfaces[0] << ":" << object_path << "]:" << err->message << std::endl; } // Remove the object from the D-Bus g_dbus_connection_unregister_object(dbuscon, object_id); // Allow the implementor to add more cleaning up callback_destructor(); // Remove the introspection document from memory g_dbus_node_info_unref(introspection); introspection = nullptr; } /** * Called each time a D-Bus client calls an object method */ // clang-format off // bug in clang-format causes "= 0" to be wrapped virtual void callback_method_call(GDBusConnection *conn, const std::string sender, const std::string obj_path, const std::string intf_name, const std::string meth_name, GVariant *params, GDBusMethodInvocation *invoc) = 0; // clang-format on GVariant *_dbus_get_property_internal(GDBusConnection *conn, const std::string sender, const std::string obj_path, const std::string intf_name, const std::string property_name, GError **error) { try { return callback_get_property(conn, sender, obj_path, intf_name, property_name, error); } catch (DBusPropertyException &err) { err.SetDBusError(error); return NULL; } } /** * Called each time a D-Bus client attempts to read a D-Bus object property */ // clang-format off // bug in clang-format causes "= 0" to be wrapped virtual GVariant *callback_get_property(GDBusConnection *conn, const std::string sender, const std::string obj_path, const std::string intf_name, const std::string property_name, GError **error) = 0; // clang-format on /** * Called each time a D-Bus client attempts to modify a D-Bus object property. * This method is "private" and is the one called by the GDBus library. This * function calls the virtual callback_set_property() which needs to be * implemented by the user. Once that returns, we need to send a * signal to D-Bus that a propery changed. */ gboolean _dbus_set_property_internal(GDBusConnection *conn, const gchar *sender, const gchar *obj_path, const gchar *intf_name, const gchar *property_name, GVariant *value, GError **error) { try { GVariantBuilder *ret = callback_set_property(conn, std::string(sender), std::string(obj_path), std::string(intf_name), std::string(property_name), value, error); // If ret != NULL, we have a valid response which contains // information about what has changed. This is further // used to issue a standard D-Bus signal that an object property // have been modified; which is the signal being emitted below. if (NULL != ret) { GError *local_err = NULL; g_dbus_connection_emit_signal(conn, NULL, obj_path, "org.freedesktop.DBus.Properties", "PropertiesChanged", g_variant_new("(sa{sv}as)", intf_name, ret, NULL), &local_err); g_variant_builder_unref(ret); if (local_err) { std::stringstream err; err << "callback_set_property(interface=" << intf_name << ", path=" << object_path << ", property=" << property_name << ", value='" << value << "'" << ") failed: " << local_err->message; THROW_DBUSEXCEPTION("DBusObject", err.str()); } } else { if (NULL != *error) { // FIXME: Consider if these errors should just go to // the client or if we should send and empty // response back std::stringstream err; err << "callback_set_property(interface=" << intf_name << ", path=" << object_path << ", property=" << property_name << ", value='" << value << "'" << ") failed: " << (*error)->message; THROW_DBUSEXCEPTION("DBusObject", err.str()); } } return (NULL != ret); } catch (DBusPropertyException &err) { err.SetDBusError(error); return false; } } /** * Called each time a D-Bus client attempts to modify a D-Bus object property */ // clang-format off // bug in clang-format causes "= 0" to be wrapped virtual GVariantBuilder *callback_set_property(GDBusConnection *conn, const std::string sender, const std::string obj_path, const std::string intf_name, const std::string property_name, GVariant *value, GError **error) = 0; // clang-format on /** * Simple helper wrapper preparing the signal response needed by call_set_property() * This prepares the response packet which is sent as a signal to D-Bus about which * property was changed. * * This is the string value variant * * @param property String containing the changed property * @param value String containing the new value * * @return Returns a GVariantBuilder pointer which is to be consumed by * _dbus_set_property_internal() * */ GVariantBuilder *build_set_property_response(std::string property, std::string value) { GVariantBuilder *builder = g_variant_builder_new(G_VARIANT_TYPE_ARRAY); g_variant_builder_add(builder, "{sv}", property.c_str(), g_variant_new_string(value.c_str())); return builder; } /** * Simple helper wrapper preparing the signal response needed by call_set_property() * This prepares the response packet which is sent as a signal to D-Bus about which * property was changed. * * This is the boolean value variant * * @param property String containing the changed property * @param value String containing the new value * * @return Returns a GVariantBuilder pointer which is to be consumed by * _dbus_set_property_internal() * */ GVariantBuilder *build_set_property_response(std::string property, const gboolean value) { GVariantBuilder *builder = g_variant_builder_new(G_VARIANT_TYPE_ARRAY); g_variant_builder_add(builder, "{sv}", property.c_str(), g_variant_new_boolean(value)); return builder; } /** * Simple helper wrapper preparing the signal response needed by call_set_property() * This prepares the response packet which is sent as a signal to D-Bus about which * property was changed. * * This is the uint value variant * * @param property String containing the changed property * @param value String containing the new value * * @return Returns a GVariantBuilder pointer which is to be consumed by * _dbus_set_property_internal() * */ GVariantBuilder *build_set_property_response(std::string property, const guint value) { GVariantBuilder *builder = g_variant_builder_new(G_VARIANT_TYPE_ARRAY); g_variant_builder_add(builder, "{sv}", property.c_str(), g_variant_new_uint32(value)); return builder; } /** * Simple helper wrapper preparing the signal response needed by call_set_property() * This prepares the response packet which is sent as a signal to D-Bus about which * property was changed. * * This is the uint64 value variant * * @param property String containing the changed property * @param value unit64 containing the new value * * @return Returns a GVariantBuilder pointer which is to be consumed by * _dbus_set_property_internal() * */ GVariantBuilder *build_set_property_response(std::string property, const uint64_t value) { GVariantBuilder *builder = g_variant_builder_new(G_VARIANT_TYPE_ARRAY); g_variant_builder_add(builder, "{sv}", property.c_str(), g_variant_new_uint64(value)); return builder; } /** * Simple helper wrapper preparing the signal response needed by call_set_property() * This prepares the response packet which is sent as a signal to D-Bus about which * property was changed. * * This is a std::time_t to uint64_t value wrapper * * @param property String containing the changed property * @param value std::time_t containing the new value * * @return Returns a GVariantBuilder pointer which is to be consumed by * _dbus_set_property_internal() * */ GVariantBuilder *build_set_property_response(std::string property, const std::time_t value) { return build_set_property_response(property, (uint64_t)value); } /** * This destructor is optional and may be used by implementors to clean up * before this object is deleted from both the D-Bus bus and memory. This * function is called from RemoveObject() right after the object is unregistered * from the D-Bus. */ virtual void callback_destructor() { } protected: /** * Parses and processes the introspection XML document * describing this object. This is used when registering this object * to the D-Bus bus. * * @param xmlstr std::string containing the introspection XML document to use */ void ParseIntrospectionXML(std::string xmlstr) { if (registered) { THROW_DBUSEXCEPTION("DBusObject", "Object is already registered in D-Bus. " "Cannot modify the introspection document."); } GError *error = nullptr; introspection = g_dbus_node_info_new_for_xml(xmlstr.c_str(), &error); if (NULL == introspection || NULL != error) { THROW_DBUSEXCEPTION("DBusObject", "Failed to parse introspection XML:" + std::string(error->message)); } } /** * Parses and processes the introspection XML document * describing this object. This is used when registering this object * to the D-Bus bus. * * @param xmlstr std::stringstream containing the introspection XML document to use */ void ParseIntrospectionXML(std::stringstream &xmlstr) { ParseIntrospectionXML(xmlstr.str()); } /** * Updates the IdleCheck timer's timestamp to indicate this object have been accessed. * If the IdleCheck object times out, the process is stopped. */ void IdleCheck_UpdateTimestamp() { if (idle_checker) { idle_checker->UpdateTimestamp(); } } /** * Get the object pointer to the registered IdleCheck object * * @returns Returns a pointer to an IdleCheck object or nullptr if not set/registered */ IdleCheck *IdleCheck_Get() { return idle_checker; } void IdleCheck_RefInc() { if (idle_checker) { idle_checker->RefCountInc(); } } void IdleCheck_RefDec() { if (idle_checker) { idle_checker->RefCountDec(); } } private: bool registered; std::string object_path; guint object_id; IdleCheck *idle_checker; GDBusNodeInfo *introspection; /** * Callback loook-up table for D-Bus */ GDBusInterfaceVTable dbusobj_interface_vtable = { dbusobject_callback_method_call, dbusobject_callback_get_property, dbusobject_callback_set_property}; static void dbusobject_callback_method_call(GDBusConnection *conn, const gchar *sender, const gchar *obj_path, const gchar *intf_name, const gchar *meth_name, GVariant *params, GDBusMethodInvocation *invoc, gpointer this_ptr) { class DBusObject *obj = (class DBusObject *)this_ptr; obj->callback_method_call(conn, std::string(sender), std::string(obj_path), std::string(intf_name), std::string(meth_name), params, invoc); } static GVariant *dbusobject_callback_get_property(GDBusConnection *conn, const gchar *sender, const gchar *obj_path, const gchar *intf_name, const gchar *property_name, GError **error, gpointer this_ptr) { class DBusObject *obj = (class DBusObject *)this_ptr; return obj->_dbus_get_property_internal(conn, std::string(sender), std::string(obj_path), std::string(intf_name), std::string(property_name), error); } static gboolean dbusobject_callback_set_property(GDBusConnection *conn, const gchar *sender, const gchar *obj_path, const gchar *intf_name, const gchar *property_name, GVariant *value, GError **error, gpointer this_ptr) { class DBusObject *obj = (class DBusObject *)this_ptr; return obj->_dbus_set_property_internal(conn, sender, obj_path, intf_name, property_name, value, error); } };