kdesktop: make sure the saver/lock remains responsive even when invokation has failed.

This could happen for example when a popup menu is open and the saver
autolock timeout expires. Before this commit, both kdesktop and the
X11 server would be in a dirty start and the saver/lock would either not
work anymore or not hide the windows on the screen.
It was necessary to kill and restart kdesktop to restore proper
functionality.

Note: the conditional return value of 0 or 12 at main.cpp:554 is a temporary
measure to prevent the screen to forcibly lock if the user forgets a popup
menu open and the saver timeout expires. Once the issue with input grabbing
is solved, we can remove the conditional return value and simply return an error
in such condition. Same applies to the variable trinity_desktop_lock_failed_grab,
which will no longer be needed in such case.o

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>

1 files changed, 32 insertions, 19 deletions

diff --git a/kdesktop/lock/lockprocess.cpp b/kdesktop/lock/lockprocess.cpp
index 789ceee0f..48af0496e 100644
--- a/kdesktop/lock/lockprocess.cpp
+++ b/kdesktop/lock/lockprocess.cpp
@@ -151,14 +151,6 @@ Atom kde_wm_system_modal_notification = 0;
 Atom kde_wm_transparent_to_desktop = 0;
 Atom kde_wm_transparent_to_black = 0;
 
-static void segv_handler(int)
-{
-	kdError(KDESKTOP_DEBUG_ID) << "A fatal exception was encountered."
-		<< " Trapping and ignoring it so as not to compromise desktop security..."
-		<< kdBacktrace() << endl;
-	sleep(1);
-}
-
 extern Atom tqt_wm_state;
 extern bool trinity_desktop_lock_use_system_modal_dialogs;
 extern bool trinity_desktop_lock_delay_screensaver_start;
@@ -166,6 +158,7 @@ extern bool trinity_desktop_lock_use_sak;
 extern bool trinity_desktop_lock_hide_active_windows;
 extern bool trinity_desktop_lock_hide_cancel_button;
 extern bool trinity_desktop_lock_forced;
+extern bool trinity_desktop_lock_failed_grab;
 
 extern LockProcess* trinity_desktop_lock_process;
 
@@ -176,6 +169,21 @@ extern TQXLibWindowList trinity_desktop_lock_hidden_window_list;
 
 bool trinity_desktop_lock_autohide_lockdlg = true;
 
+static void segv_handler(int)
+{
+	// Try to send a USR1 signal to kdesktop to make sure it does not get
+	// stuck into an `Engaging` state in case kdesktop_lock crashes.
+	// This prevents the locking mechanism from becaming unresponsive
+	// in case of exceptions.
+	kill(kdesktop_pid, SIGUSR1);
+
+	kdError(KDESKTOP_DEBUG_ID) << "A fatal exception was encountered."
+		<< " Trapping and ignoring it so as not to compromise desktop security..."
+		<< kdBacktrace() << endl;
+
+	sleep(1);
+}
+
 #define ENABLE_CONTINUOUS_LOCKDLG_DISPLAY \
 if (!mForceContinualLockDisplayTimer->isActive()) mForceContinualLockDisplayTimer->start(100, false); \
 trinity_desktop_lock_autohide_lockdlg = false; \
@@ -234,7 +242,9 @@ LockProcess::LockProcess()
 	m_notifyReadyRequested(false),
 	m_loginCardDevice(NULL),
 	m_maskWidget(NULL),
-	m_saverRootWindow(0)
+	m_saverRootWindow(0),
+	mControlPipeHandler(nullptr),
+	mControlPipeHandlerThread(nullptr)
 {
 #ifdef KEEP_MOUSE_UNGRABBED
 	setNFlags(WX11DisableMove|WX11DisableClose|WX11DisableShade|WX11DisableMinimize|WX11DisableMaximize);
@@ -331,8 +341,6 @@ LockProcess::~LockProcess()
 	mControlPipeHandler->terminateThread();
 	mControlPipeHandlerThread->wait();
 	delete mControlPipeHandler;
-// 	delete mControlPipeHandlerThread;
-
 	if (resizeTimer != NULL) {
 		resizeTimer->stop();
 		delete resizeTimer;
@@ -412,9 +420,7 @@ void LockProcess::init(bool child, bool useBlankOnly)
 	}
 #endif
 
-#if (TQT_VERSION-0 >= 0x030200) // XRANDR support
 	connect( tdeApp->desktop(), TQ_SIGNAL( resized( int )), TQ_SLOT( desktopResized()));
-#endif
 
 	if (!trinity_desktop_lock_use_system_modal_dialogs) {
 		setWFlags((WFlags)WX11BypassWM);
@@ -438,6 +444,12 @@ void LockProcess::init(bool child, bool useBlankOnly)
 	TQObject::connect(mControlPipeHandler, TQ_SIGNAL(processCommand(TQString)), this, TQ_SLOT(processInputPipeCommand(TQString)));
 	TQTimer::singleShot(0, mControlPipeHandler, TQ_SLOT(run()));
 	mControlPipeHandlerThread->start();
+	// If the lock process terminates before 'mControlPipeHandler::run()' has been called, the
+	// 'mControlPipeHandlerThread' thread would not terminate and the lock process would have a
+	// dirty exit, potentially leaving 'kdesktop' in a dirty state that prevents the lock from
+	// working correctly till 'kdesktop' is killed and restarted. By forcing a call to 'processEvents()'
+	// we make sure to handle pending timer events and execute the required call
+	tdeApp->processEvents();
 }
 
 static int signal_pipe[2];
@@ -566,7 +578,7 @@ bool LockProcess::lock()
 	m_startupStatusDialog->setStatusMessage(i18n("Securing desktop session").append("..."));
 	m_startupStatusDialog->show();
 	m_startupStatusDialog->setActiveWindow();
-	tqApp->processEvents();
+	tdeApp->processEvents();
 #endif
 
 	if (startSaver(true)) {
@@ -722,7 +734,7 @@ bool LockProcess::runSecureDialog()
 	m_startupStatusDialog->setStatusMessage(i18n("Securing desktop session").append("..."));
 	m_startupStatusDialog->show();
 	m_startupStatusDialog->setActiveWindow();
-	tqApp->processEvents();
+	tdeApp->processEvents();
 #endif
 
 	mInSecureDialog = true;
@@ -1343,6 +1355,7 @@ bool LockProcess::startSaver(bool notify_ready)
 	if (!child_saver && !grabInput())
 	{
 		kdWarning(KDESKTOP_DEBUG_ID) << "LockProcess::startSaver() grabInput() failed!!!!" << endl;
+		trinity_desktop_lock_failed_grab = true;
 		return false;
 	}
 	mBusy = false;
@@ -2308,7 +2321,7 @@ bool LockProcess::x11Event(XEvent *event)
 		&& event->xkey.window != mDialogs.first()->winId()) {
 		XEvent ev2 = *event;
 		ev2.xkey.window = ev2.xkey.subwindow = mDialogs.first()->winId();
-		tqApp->x11ProcessEvent( &ev2 );
+		tdeApp->x11ProcessEvent( &ev2 );
 		return true;
 	}
 
@@ -2963,7 +2976,7 @@ void LockProcess::saverReady() {
 // Control pipe handler
 //
 ControlPipeHandlerObject::ControlPipeHandlerObject() : TQObject() {
-	mParent = NULL;
+	mParent = nullptr;
 	mRunning = false;
 	mTerminate = false;
 	mThreadID = 0L;
@@ -2987,7 +3000,7 @@ void ControlPipeHandlerObject::run(void) {
 	int display_number = atoi(TQString(XDisplayString(tqt_xdisplay())).replace(":","").ascii());
 
 	if (display_number < 0) {
-		printf("[kdesktop_lock] Warning: unable to create control socket.  Interactive logon modules may not function properly.\n");
+		printf("[kdesktop_lock] Warning: unable to create control socket. Interactive logon modules may not function properly.\n");
 		mRunning = false;
 		TQApplication::eventLoop()->exit(-1);
 		return;
@@ -3018,7 +3031,7 @@ void ControlPipeHandlerObject::run(void) {
 	}
 
 	if (!mParent->mPipeOpen) {
-		printf("[kdesktop_lock] Warning: unable to create control socket '%s'.  Interactive logon modules may not function properly.\n", fifo_file);
+		printf("[kdesktop_lock] Warning: unable to create control socket '%s'. Interactive logon modules may not function properly.\n", fifo_file);
 		mRunning = false;
 		TQApplication::eventLoop()->exit(-1);
 		return;