path: root/kdesktop/lockeng.cc

//===========================================================================
//
// This file is part of the TDE project
//
// Copyright (c) 1999 Martin R. Jones <mjones@kde.org>
// Copyright (c) 2012 Timothy Pearson <kb9vqf@pearsoncomputing.net>
//


#include <config.h>

#include <stdlib.h>

#include <ksslcertificate.h>

#include <tdehardwaredevices.h>
#include <tdecryptographiccarddevice.h>

#include <kstandarddirs.h>
#include <tdeapplication.h>
#include <kservicegroup.h>
#include <kdebug.h>
#include <kuser.h>
#include <tdelocale.h>
#include <tqfile.h>
#include <tqtimer.h>
#include <tqeventloop.h>
#include <dcopclient.h>
#include <assert.h>

#include <dmctl.h>

#include <dbus/dbus-shared.h>
#include <tqdbusdata.h>
#include <tqdbuserror.h>
#include <tqdbusmessage.h>
#include <tqdbusobjectpath.h>
#include <tqdbusproxy.h>

#include "lockeng.h"
#include "lockeng.moc"
#include "kdesktopsettings.h"

#define SYSTEMD_LOGIN1_SERVICE		"org.freedesktop.login1"
#define SYSTEMD_LOGIN1_PATH		"/org/freedesktop/login1"
#define SYSTEMD_LOGIN1_MANAGER_IFACE	"org.freedesktop.login1.Manager"
#define SYSTEMD_LOGIN1_SESSION_IFACE	"org.freedesktop.login1.Session"
#define SYSTEMD_LOGIN1_SEAT_IFACE	"org.freedesktop.login1.Seat"

#define DBUS_CONN_NAME			"kdesktop_lock"

#include "xautolock_c.h"
extern xautolock_corner_t xautolock_corners[ 4 ];

bool trinity_lockeng_sak_available = TRUE;

SaverEngine* m_masterSaverEngine = NULL;
static void sigusr1_handler(int)
{
	if (m_masterSaverEngine) {
		m_masterSaverEngine->m_threadHelperObject->slotLockProcessWaiting();
	}
}
static void sigusr2_handler(int)
{
	if (m_masterSaverEngine) {
		m_masterSaverEngine->m_threadHelperObject->slotLockProcessFullyActivated();
	}
}
static void sigttin_handler(int)
{
	if (m_masterSaverEngine) {
		m_masterSaverEngine->slotLockProcessReady();
	}
}

//===========================================================================
//
// Screen saver engine. Doesn't handle the actual screensaver window,
// starting screensaver hacks, or password entry. That's done by
// a newly started process.
//
SaverEngine::SaverEngine()
	: TQWidget(),
	  KScreensaverIface(),
	  mBlankOnly(false),
	  mSAKProcess(NULL),
	  mTerminationRequested(false),
	  mSaverProcessReady(false),
	  mNewVTAfterLockEngage(false),
	  mValidCryptoCardInserted(false),
	  mSwitchVTAfterLockEngage(-1),
	  dBusLocal(0),
	  dBusWatch(0),
	  systemdSession(0)
{
	// handle SIGUSR1
	m_masterSaverEngine = this;
	mSignalAction.sa_handler= sigusr1_handler;
	sigemptyset(&(mSignalAction.sa_mask));
	sigaddset(&(mSignalAction.sa_mask), SIGUSR1);
	mSignalAction.sa_flags = 0;
	sigaction(SIGUSR1, &mSignalAction, 0L);

	// handle SIGUSR2
	m_masterSaverEngine = this;
	mSignalAction.sa_handler= sigusr2_handler;
	sigemptyset(&(mSignalAction.sa_mask));
	sigaddset(&(mSignalAction.sa_mask), SIGUSR2);
	mSignalAction.sa_flags = 0;
	sigaction(SIGUSR2, &mSignalAction, 0L);

	// handle SIGTTIN
	m_masterSaverEngine = this;
	mSignalAction.sa_handler= sigttin_handler;
	sigemptyset(&(mSignalAction.sa_mask));
	sigaddset(&(mSignalAction.sa_mask), SIGTTIN);
	mSignalAction.sa_flags = 0;
	sigaction(SIGTTIN, &mSignalAction, 0L);

	// Save X screensaver parameters
	XGetScreenSaver(tqt_xdisplay(), &mXTimeout, &mXInterval,
					&mXBlanking, &mXExposures);

	mState = Waiting;
	mXAutoLock = 0;
	mEnabled = false;

	m_helperThread = new TQEventLoopThread;
	m_helperThread->start();
	m_threadHelperObject = new SaverEngineThreadHelperObject;
	m_threadHelperObject->moveToThread(m_helperThread);
	connect(this, TQT_SIGNAL(terminateHelperThread()), m_threadHelperObject, TQT_SLOT(terminateThread()));
	connect(m_threadHelperObject, TQT_SIGNAL(lockProcessWaiting()), this, TQT_SLOT(lockProcessWaiting()));
	connect(m_threadHelperObject, TQT_SIGNAL(lockProcessFullyActivated()), this, TQT_SLOT(lockProcessFullyActivated()));

	connect(&mLockProcess, TQT_SIGNAL(processExited(TDEProcess *)),
						TQT_SLOT(lockProcessExited()));

	mSAKProcess = new TDEProcess;
	*mSAKProcess << "tdmtsak";
	connect(mSAKProcess, TQT_SIGNAL(processExited(TDEProcess*)), this, TQT_SLOT(slotSAKProcessExited()));

	TQTimer::singleShot( 0, this, TQT_SLOT(handleSecureDialog()) );

	configure();

	mLockProcess.clearArguments();
	TQString path = TDEStandardDirs::findExe( "kdesktop_lock" );
	if( path.isEmpty())
	{
		kdDebug( 1204 ) << "Can't find kdesktop_lock!" << endl;
	}
	mLockProcess << path;
	mLockProcess << TQString( "--internal" ) << TQString( "%1" ).arg(getpid());
	if (mLockProcess.start() == false )
	{
		kdDebug( 1204 ) << "Failed to start kdesktop_lock!" << endl;
	}

	// Prevent kdesktop_lock signals from being handled by the wrong (GUI) thread
	sigemptyset(&mThreadBlockSet);
	sigaddset(&mThreadBlockSet, SIGUSR1);
	sigaddset(&mThreadBlockSet, SIGUSR2);
	sigaddset(&mThreadBlockSet, SIGTTIN);
	pthread_sigmask(SIG_BLOCK, &mThreadBlockSet, NULL);

	// Initialize SmartCard readers
	TDEGenericDevice *hwdevice;
	TDEHardwareDevices *hwdevices = TDEGlobal::hardwareDevices();
	TDEGenericHardwareList cardReaderList = hwdevices->listByDeviceClass(TDEGenericDeviceType::CryptographicCard);
	for (hwdevice = cardReaderList.first(); hwdevice; hwdevice = cardReaderList.next()) {
		TDECryptographicCardDevice* cdevice = static_cast<TDECryptographicCardDevice*>(hwdevice);
		connect(cdevice, TQT_SIGNAL(certificateListAvailable(TDECryptographicCardDevice*)), this, TQT_SLOT(cryptographicCardInserted(TDECryptographicCardDevice*)));
		connect(cdevice, TQT_SIGNAL(cardRemoved(TDECryptographicCardDevice*)), this, TQT_SLOT(cryptographicCardRemoved(TDECryptographicCardDevice*)));
		cdevice->enableCardMonitoring(true);
	}

	// Check card login status
	KUser userinfo;
	TQString fileName = userinfo.homeDir() + "/.tde_card_login_state";
	TQFile flagFile(fileName);
	if (flagFile.open(IO_ReadOnly)) {
		TQTextStream stream(&flagFile);
		if (stream.readLine().startsWith("1")) {
			// Card was likely used to log in
			TQTimer::singleShot(5000, this, SLOT(cardStartupTimeout()));
		}
		flagFile.close();
	}

	dBusConnect();
}

//---------------------------------------------------------------------------
//
// Destructor - usual cleanups.
//
SaverEngine::~SaverEngine()
{
	if (mState == Waiting) {
		kill(mLockProcess.pid(), SIGKILL);
	}

	mLockProcess.detach(); // don't kill it if we crash
	delete mXAutoLock;

	dBusClose();

	// Restore X screensaver parameters
	XSetScreenSaver(tqt_xdisplay(), mXTimeout, mXInterval, mXBlanking,
					mXExposures);

	terminateHelperThread();
	m_helperThread->wait();
	delete m_threadHelperObject;
	delete m_helperThread;
}

void SaverEngine::cardStartupTimeout() {
	if (!mValidCryptoCardInserted) {
		// Restore saver timeout
		configure();

		// Force lock
		lockScreen();
	}
}

void SaverEngine::cryptographicCardInserted(TDECryptographicCardDevice* cdevice) {
	TQString login_name = TQString::null;
	X509CertificatePtrList certList = cdevice->cardX509Certificates();
	if (certList.count() > 0) {
		KSSLCertificate* card_cert = NULL;
		card_cert = KSSLCertificate::fromX509(certList[0]);
		TQStringList cert_subject_parts = TQStringList::split("/", card_cert->getSubject(), false);
		for (TQStringList::Iterator it = cert_subject_parts.begin(); it != cert_subject_parts.end(); ++it ) {
			TQString lcpart = (*it).lower();
			if (lcpart.startsWith("cn=")) {
				login_name = lcpart.right(lcpart.length() - strlen("cn="));
			}
		}
		delete card_cert;
	}

	if (login_name != "") {
		KUser user;
		if (login_name == user.loginName()) {
			mValidCryptoCardInserted = true;
			// Disable saver startup
			enable(false);
		}
	}
}

void SaverEngine::cryptographicCardRemoved(TDECryptographicCardDevice* cdevice) {
	if (mValidCryptoCardInserted) {
		// Restore saver timeout
		configure();

		// Force lock
		lockScreen();
	}
	mValidCryptoCardInserted = false;
}

//---------------------------------------------------------------------------
//
// This should be called only using DCOP.
//
void SaverEngine::lock()
{
	lockScreen(true);
}

//---------------------------------------------------------------------------
//
// Lock the screen
//
void SaverEngine::lockScreen(bool DCOP)
{
	bool ok = true;
	if (mState != Saving)
	{
		ok = startLockProcess( ForceLock );
		// It takes a while for kdesktop_lock to start and lock the screen.
		// Therefore delay the DCOP call until it tells kdesktop that the locking is in effect.
		// This is done only for --forcelock .
		if( ok && mState != Saving )
		{
			if (DCOP) {
				DCOPClientTransaction* trans = kapp->dcopClient()->beginTransaction();
				if (trans) {
					mLockTransactions.append( trans );
				}
			}
		}
	}
	else
	{
		mLockProcess.kill( SIGHUP );
	}
}

void SaverEngine::processLockTransactions()
{
	for( TQValueVector< DCOPClientTransaction* >::ConstIterator it = mLockTransactions.begin();
		 it != mLockTransactions.end();
		 ++it )
	{
		TQCString replyType = "void";
		TQByteArray arr;
		kapp->dcopClient()->endTransaction( *it, replyType, arr );
	}
	mLockTransactions.clear();
}

void SaverEngine::saverLockReady()
{
	if( mState != Engaging )
	{
		kdDebug( 1204 ) << "Got unexpected saverReady()" << endl;
	}
	kdDebug( 1204 ) << "Saver Lock Ready" << endl;
	processLockTransactions();
}

//---------------------------------------------------------------------------
void SaverEngine::save()
{
	if (mState == Waiting)
	{
		startLockProcess( DefaultLock );
	}
}

//---------------------------------------------------------------------------
void SaverEngine::quit()
{
	if (mState == Saving || mState == Engaging)
	{
		stopLockProcess();
	}
}

//---------------------------------------------------------------------------
bool SaverEngine::isEnabled()
{
	return mEnabled;
}

//---------------------------------------------------------------------------
bool SaverEngine::enable( bool e )
{
	if ( e == mEnabled )
	return true;

	// If we aren't in a suitable state, we will not reconfigure.
	if (mState != Waiting)
		return false;

	mEnabled = e;

	if (mEnabled) {
		if ( !mXAutoLock ) {
			mXAutoLock = new XAutoLock();
			connect(mXAutoLock, TQT_SIGNAL(timeout()), TQT_SLOT(idleTimeout()));
		}
		mXAutoLock->setTimeout(mTimeout);
		mXAutoLock->setDPMS(true);
		//mXAutoLock->changeCornerLockStatus( mLockCornerTopLeft, mLockCornerTopRight, mLockCornerBottomLeft, mLockCornerBottomRight);
	
		// We'll handle blanking
		XSetScreenSaver(tqt_xdisplay(), mTimeout + 10, mXInterval, PreferBlanking, mXExposures);
		kdDebug() << "XSetScreenSaver " << mTimeout + 10 << endl;

		mXAutoLock->start();

		kdDebug(1204) << "Saver Engine started, timeout: " << mTimeout << endl;
	}
	else {
		if (mXAutoLock) {
			delete mXAutoLock;
			mXAutoLock = 0;
		}
	
		XForceScreenSaver(tqt_xdisplay(), ScreenSaverReset );
		XSetScreenSaver(tqt_xdisplay(), 0, mXInterval,  PreferBlanking, DontAllowExposures);
		kdDebug(1204) << "Saver Engine disabled" << endl;
	}

	return true;
}

//---------------------------------------------------------------------------
bool SaverEngine::isBlanked()
{
	return (mState != Waiting);
}

void SaverEngine::enableExports()
{
#ifdef Q_WS_X11
	kdDebug(270) << k_lineinfo << "activating background exports.\n";
	DCOPClient *client = kapp->dcopClient();
	if (!client->isAttached()) {
		client->attach();
	}
	TQByteArray data;
	TQDataStream args( data, IO_WriteOnly );
	args << 1;
	
	TQCString appname( "kdesktop" );
	int screen_number = DefaultScreen(tqt_xdisplay());
	if ( screen_number ) {
		appname.sprintf("kdesktop-screen-%d", screen_number );
	}
	
	client->send( appname, "KBackgroundIface", "setExport(int)", data );
#endif
}

//---------------------------------------------------------------------------
void SaverEngine::handleSecureDialog()
{
	// Wait for SAK press
	if (!mSAKProcess->isRunning()) mSAKProcess->start();
}

void SaverEngine::slotSAKProcessExited()
{
	int retcode = mSAKProcess->exitStatus();
	if ((retcode != 0) && (mSAKProcess->normalExit())) {
		trinity_lockeng_sak_available = FALSE;
		printf("[kdesktop] SAK driven secure dialog is not available for use (retcode %d).  Check tdmtsak for proper functionality.\n", retcode); fflush(stdout);
	}

	if (mState == Preparing) {
		return;
	}

	if ((mSAKProcess->normalExit()) && (trinity_lockeng_sak_available == TRUE)) {
		bool ok = true;
		if (mState == Waiting)
		{
			ok = startLockProcess( SecureDialog );
			if( ok && mState != Saving )
			{
			}
		}
		else
		{
			mLockProcess.kill( SIGHUP );
		}
	}
}

//---------------------------------------------------------------------------
//
// Read and apply configuration.
//
void SaverEngine::configure()
{
	// If we aren't in a suitable state, we will not reconfigure.
	if (mState != Waiting) {
		return;
	}

	// create a new config obj to ensure we read the latest options
	KDesktopSettings::self()->readConfig();

	bool e = KDesktopSettings::screenSaverEnabled();
	mTimeout = KDesktopSettings::timeout();

	mEnabled = !e;   // force the enable()

	int action;
	action = KDesktopSettings::actionTopLeft();
	xautolock_corners[0] = applyManualSettings(action);
	action = KDesktopSettings::actionTopRight();
	xautolock_corners[1] = applyManualSettings(action);
	action = KDesktopSettings::actionBottomLeft();
	xautolock_corners[2] = applyManualSettings(action);
	action = KDesktopSettings::actionBottomRight();
	xautolock_corners[3] = applyManualSettings(action);

	enable( e );
}

//---------------------------------------------------------------------------
//
//  Set a variable to indicate only using the blanker and not the saver.
//
void SaverEngine::setBlankOnly( bool blankOnly )
{
	mBlankOnly = blankOnly;
	// FIXME: if running, stop and restart?  What about security
	// implications of this?
}

bool SaverEngine::restartDesktopLockProcess()
{
	if (!mLockProcess.isRunning()) {
		mSaverProcessReady = false;
		mLockProcess.clearArguments();
		TQString path = TDEStandardDirs::findExe( "kdesktop_lock" );
		if (path.isEmpty()) {
			kdDebug( 1204 ) << "Can't find kdesktop_lock!" << endl;
			return false;
		}
		mLockProcess << path;
		mLockProcess << TQString( "--internal" ) << TQString( "%1" ).arg(getpid());
		if (mLockProcess.start() == false) {
			kdDebug( 1204 ) << "Failed to start kdesktop_lock!" << endl;
			return false;
		}
		// Wait for the saver process to signal ready...
		if (!waitForLockProcessStart()) {
			kdDebug( 1204 ) << "Failed to initialize kdesktop_lock (unexpected termination)!" << endl;
			return false;
		}
	}
	return true;
}

//---------------------------------------------------------------------------
//
// Start the screen saver.
//
bool SaverEngine::startLockProcess( LockType lock_type )
{
	int ret;

	if (mState == Saving) {
		return true;
	}

	mState = Preparing;
	mSAKProcess->kill(SIGTERM);

	enableExports();

	kdDebug(1204) << "SaverEngine: starting saver" << endl;
	emitDCOPSignal("KDE_start_screensaver()", TQByteArray());

	if (!restartDesktopLockProcess()) {
		mState = Waiting;
		return false;
	}

	switch( lock_type )
	{
		case ForceLock:
			mLockProcess.kill(SIGUSR1);		// Request forcelock
			break;
		case DontLock:
			mLockProcess.kill(SIGUSR2);		// Request dontlock
			break;
		case SecureDialog:
			mLockProcess.kill(SIGWINCH);	// Request secure dialog
			break;
		default:
			break;
	}
	if (mBlankOnly) {
		mLockProcess.kill(SIGTTIN);		// Request blanking
	}

	ret = mLockProcess.kill(SIGTTOU);			// Start lock
	if (!ret) {
		mState = Waiting;
		return false;
	}
	XSetScreenSaver(tqt_xdisplay(), 0, mXInterval,  PreferBlanking, mXExposures);

	mState = Engaging;
	if (mXAutoLock) {
		mXAutoLock->stop();
	}
	return true;
}

//---------------------------------------------------------------------------
//
// Stop the screen saver.
//
void SaverEngine::stopLockProcess()
{
	if (mState == Waiting) {
		kdWarning(1204) << "SaverEngine::stopSaver() saver not active" << endl;
		return;
	}
	kdDebug(1204) << "SaverEngine: stopping lock" << endl;
	emitDCOPSignal("KDE_stop_screensaver()", TQByteArray());

	mTerminationRequested = true;
	mLockProcess.kill();

	if (mEnabled) {
		if (mXAutoLock) {
			mXAutoLock->start();
		}
		XForceScreenSaver(tqt_xdisplay(), ScreenSaverReset );
		XSetScreenSaver(tqt_xdisplay(), mTimeout + 10, mXInterval, PreferBlanking, mXExposures);
	}
	processLockTransactions();
	mState = Waiting;

	if( systemdSession && systemdSession->canSend() ) {
		TQValueList<TQT_DBusData> params;
		params << TQT_DBusData::fromBool(false);
		TQT_DBusMessage reply = systemdSession->sendWithReply("SetIdleHint", params);
	}
}

void SaverEngine::recoverFromHackingAttempt()
{
	// Try to relaunch saver with forcelock
	if (!startLockProcess(ForceLock)) {
		// Terminate the TDE session ASAP!
		// Values are explained at http://lists.kde.org/?l=kde-linux&m=115770988603387
		TQByteArray data;
		TQDataStream arg(data, IO_WriteOnly);
		arg << (int)0 << (int)0 << (int)2;
		if (!kapp->dcopClient()->send("ksmserver", "default", "logout(int,int,int)", data)) {
			// Someone got to DCOP before we did
			// Try an emergency system logout
			system("logout");
		}
	}
}

void SaverEngine::lockProcessExited()
{
	bool abnormalExit = false;
	if (mLockProcess.normalExit() == false) {
		abnormalExit = true;
	}
	else {
		if (mLockProcess.exitStatus() != 0) {
			abnormalExit = true;
		}
	}
	if (mTerminationRequested == true) {
		abnormalExit = false;
		mTerminationRequested = false;
	}
	if (abnormalExit == true) {
		// PROBABLE HACKING ATTEMPT DETECTED
		restartDesktopLockProcess();
		mState = Waiting;
		TQTimer::singleShot( 100, this, SLOT(recoverFromHackingAttempt()) );
	}
	else {
		// Restart the lock process
		restartDesktopLockProcess();
	}
}

void SaverEngineThreadHelperObject::slotLockProcessWaiting()
{
	// lockProcessWaiting cannot be called directly from a signal handler, as it will hang in certain obscure circumstances
	// Instead we use a single-shot timer to immediately call lockProcessWaiting once control has returned to the Qt main loop
	lockProcessWaiting();
}

void SaverEngineThreadHelperObject::slotLockProcessFullyActivated()
{
	lockProcessFullyActivated();
}

void SaverEngine::lockProcessFullyActivated()
{
	mState = Saving;

	if( systemdSession && systemdSession->canSend() ) {
		TQValueList<TQT_DBusData> params;
		params << TQT_DBusData::fromBool(true);
		TQT_DBusMessage reply = systemdSession->sendWithReply("SetIdleHint", params);
	}

	if (mNewVTAfterLockEngage) {
		DM().startReserve();
		mNewVTAfterLockEngage = false;
	}
	else if (mSwitchVTAfterLockEngage != -1) {
		DM().switchVT(mSwitchVTAfterLockEngage);
		mSwitchVTAfterLockEngage = -1;
	}
}

void SaverEngine::slotLockProcessReady()
{
	mSaverProcessReady = true;
}

void SaverEngine::lockProcessWaiting()
{
	kdDebug(1204) << "SaverEngine: lock exited" << endl;
	if (trinity_lockeng_sak_available == TRUE) {
		handleSecureDialog();
	}
	if( mState == Waiting ) {
		return;
	}
	emitDCOPSignal("KDE_stop_screensaver()", TQByteArray());
	if (mEnabled) {
		if (mXAutoLock) {
			mXAutoLock->start();
		}
		XForceScreenSaver(tqt_xdisplay(), ScreenSaverReset );
		XSetScreenSaver(tqt_xdisplay(), mTimeout + 10, mXInterval, PreferBlanking, mXExposures);
	}
	processLockTransactions();
	mState = Waiting;

	if( systemdSession && systemdSession->canSend() ) {
		TQValueList<TQT_DBusData> params;
		params << TQT_DBusData::fromBool(false);
		TQT_DBusMessage reply = systemdSession->sendWithReply("SetIdleHint", params);
	}
}

//---------------------------------------------------------------------------
//
// XAutoLock has detected the required idle time.
//
void SaverEngine::idleTimeout()
{
	// disable X screensaver
	XForceScreenSaver(tqt_xdisplay(), ScreenSaverReset );
	XSetScreenSaver(tqt_xdisplay(), 0, mXInterval, PreferBlanking, DontAllowExposures);
	startLockProcess( DefaultLock );
}

xautolock_corner_t SaverEngine::applyManualSettings(int action)
{
	if (action == 0) {
		kdDebug() << "no lock" << endl;
		return ca_nothing;
	}
	else if (action == 1) {
		kdDebug() << "lock screen" << endl;
		return ca_forceLock;
	}
	else if (action == 2) {
		kdDebug() << "prevent lock" << endl;
		return ca_dontLock;
	}
	else{
		kdDebug() << "no lock nothing" << endl;
		return ca_nothing;
	}
}

/*!
 * This function try a reconnect to D-Bus.
 * \return boolean with the result of the operation
 * \retval true if successful reconnected to D-Bus
 * \retval false if unsuccessful
 */
bool SaverEngine::dBusReconnect() {
	// close D-Bus connection
	dBusClose();
	// init D-Bus conntection
	return (dBusConnect());
}

/*!
 * This function is used to close D-Bus connection.
 */
void SaverEngine::dBusClose() {
	if( dBusConn.isConnected() ) {
		if( dBusLocal ) {
			delete dBusLocal;
			dBusLocal = 0;
		}
		if( dBusWatch ) {
			delete dBusWatch;
			dBusWatch = 0;
		}
		if( systemdSession ) {
			delete systemdSession;
			systemdSession = 0;
		}
	}
	dBusConn.closeConnection(DBUS_CONN_NAME);
}

/*!
 * This function is used to connect to D-Bus.
 */
bool SaverEngine::dBusConnect() {
	dBusConn = TQT_DBusConnection::addConnection(TQT_DBusConnection::SystemBus, DBUS_CONN_NAME);
	if( !dBusConn.isConnected() ) {
		kdError() << "Failed to open connection to system message bus: " << dBusConn.lastError().message() << endl;
		TQTimer::singleShot(4000, this, TQT_SLOT(dBusReconnect()));
		return false;
	}

	// watcher for Disconnect signal
	dBusLocal = new TQT_DBusProxy(DBUS_SERVICE_DBUS, DBUS_PATH_LOCAL, DBUS_INTERFACE_LOCAL, dBusConn);
	TQObject::connect(dBusLocal, TQT_SIGNAL(dbusSignal(const TQT_DBusMessage&)),
			  this, TQT_SLOT(handleDBusSignal(const TQT_DBusMessage&)));

	// watcher for NameOwnerChanged signals
	dBusWatch = new TQT_DBusProxy(DBUS_SERVICE_DBUS, DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, dBusConn);
	TQObject::connect(dBusWatch, TQT_SIGNAL(dbusSignal(const TQT_DBusMessage&)),
			  this, TQT_SLOT(handleDBusSignal(const TQT_DBusMessage&)));

	// find already running SystemD
	TQT_DBusProxy checkSystemD(DBUS_SERVICE_DBUS, DBUS_PATH_DBUS, DBUS_INTERFACE_DBUS, dBusConn);
	if( checkSystemD.canSend() ) {
		TQValueList<TQT_DBusData> params;
		params << TQT_DBusData::fromString(SYSTEMD_LOGIN1_SERVICE);
		TQT_DBusMessage reply = checkSystemD.sendWithReply("NameHasOwner", params);
		if (reply.type() == TQT_DBusMessage::ReplyMessage && reply.count() == 1 && reply[0].toBool() ) {
			onDBusServiceRegistered(SYSTEMD_LOGIN1_SERVICE);
		}
	}
	return true;
}

/*!
 * This function handles D-Bus service registering
 */
void SaverEngine::onDBusServiceRegistered(const TQString& service) {
	if( service == SYSTEMD_LOGIN1_SERVICE ) {
		// get current systemd session
		TQT_DBusProxy managerIface(SYSTEMD_LOGIN1_SERVICE, SYSTEMD_LOGIN1_PATH, SYSTEMD_LOGIN1_MANAGER_IFACE, dBusConn);
		TQT_DBusObjectPath systemdSessionPath = TQT_DBusObjectPath();
		if( managerIface.canSend() ) {
			TQValueList<TQT_DBusData> params;
			params << TQT_DBusData::fromUInt32( getpid() );
			TQT_DBusMessage reply = managerIface.sendWithReply("GetSessionByPID", params);
			if (reply.type() == TQT_DBusMessage::ReplyMessage && reply.count() == 1 ) {
				systemdSessionPath = reply[0].toObjectPath();
			}
		}
		// wather for systemd session signals
		if( systemdSessionPath.isValid() ) {
			systemdSession = new TQT_DBusProxy(SYSTEMD_LOGIN1_SERVICE, systemdSessionPath, SYSTEMD_LOGIN1_SESSION_IFACE, dBusConn);
			TQObject::connect(systemdSession, TQT_SIGNAL(dbusSignal(const TQT_DBusMessage&)),
					  this, TQT_SLOT(handleDBusSignal(const TQT_DBusMessage&)));
		}
		return;
	}
}

/*!
 * This function handles D-Bus service unregistering
 */
void SaverEngine::onDBusServiceUnregistered(const TQString& service) {
	if( service == SYSTEMD_LOGIN1_SERVICE ) {
		if( systemdSession ) {
			delete systemdSession;
			systemdSession = 0;
		}
		return;
	}
}

/*!
 * This function handles signals from the D-Bus daemon.
 */
void SaverEngine::handleDBusSignal(const TQT_DBusMessage& msg) {
	// dbus terminated
	if( msg.path() == DBUS_PATH_LOCAL
	 && msg.interface() == DBUS_INTERFACE_LOCAL
	 && msg.member() == "Disconnected" ) {
		dBusClose();
		TQTimer::singleShot(1000, this, TQT_SLOT(dBusReconnect()));
		return;
	}

	// service registered / unregistered
	if( msg.path() == DBUS_PATH_DBUS
	 && msg.interface() == DBUS_INTERFACE_DBUS
	 && msg.member() == "NameOwnerChanged" ) {
		if( msg[1].toString().isEmpty() ) {
			// old-owner is empty
			onDBusServiceRegistered(msg[0].toString());
		}
		if( msg[2].toString().isEmpty() ) {
			// new-owner is empty
			onDBusServiceUnregistered(msg[0].toString());
		}
		return;
	}

	// systemd signal Lock()
	if( systemdSession && systemdSession->canSend()
	 && msg.path() == systemdSession->path()
	 && msg.interface() == SYSTEMD_LOGIN1_SESSION_IFACE
	 && msg.member() == "Lock") {
		lockScreen();
		return;
	}

	// systemd signal Unlock()
	if( systemdSession && systemdSession->canSend()
	 && msg.path() == systemdSession->path()
	 && msg.interface() == SYSTEMD_LOGIN1_SESSION_IFACE
	 && msg.member() == "Unlock") {
		// unlock?
		return;
	}
}

bool SaverEngine::waitForLockProcessStart() {
	sigset_t new_mask;
	sigset_t empty_mask;
	sigemptyset(&empty_mask);

	// ensure that SIGCHLD is not subject to a race condition
	sigemptyset(&new_mask);
	sigaddset(&new_mask, SIGCHLD);

	pthread_sigmask(SIG_BLOCK, &new_mask, NULL);
	while ((mLockProcess.isRunning()) && (!mSaverProcessReady)) {
		// wait for any signal(s) to arrive
		sigsuspend(&empty_mask);
	}
	pthread_sigmask(SIG_UNBLOCK, &new_mask, NULL);

	return mLockProcess.isRunning();
}

bool SaverEngine::waitForLockEngage() {
	sigset_t empty_mask;
	sigemptyset(&empty_mask);

	// wait for SIGUSR1, SIGUSR2, SIGTTIN
	while ((mLockProcess.isRunning()) && (mState != Waiting) && (mState != Saving)) {
		// wait for any signal(s) to arrive
		sigsuspend(&empty_mask);
	}

	return mLockProcess.isRunning();
}

void SaverEngine::lockScreenAndDoNewSession() {
	mNewVTAfterLockEngage = true;
	lockScreen();
}

void SaverEngine::lockScreenAndSwitchSession(int vt) {
	mSwitchVTAfterLockEngage = vt;
	lockScreen();
}

void SaverEngineThreadHelperObject::terminateThread() {
	TQEventLoop* eventLoop = TQApplication::eventLoop();
	if (eventLoop) {
		eventLoop->exit(0);
	}
}