Clean up and modernize code

- static "new-style" signal->slot connections
- Fix a lot of things Clang-Tidy complained about
- Move includes to .cpp files and use forward decls in .h
- Don't use <QtWidgets> and <QtCore>, but specific includes instead

52 files changed, 741 insertions, 844 deletions

diff --git a/src/client/addons/addons.cpp b/src/client/addons/addons.cpp
index 43813ee..d39e53c 100644
--- a/src/client/addons/addons.cpp
+++ b/src/client/addons/addons.cpp
@@ -30,13 +30,12 @@ QList<Addon*> AddonManager::_addons;
 class Addon
 {
 public:
-	Addon() : button(nullptr), menu(nullptr), wantConnectInfo(false) {}
-	QPushButton *button;
-	QAction *menu;
+	QPushButton *button{};
+	QAction *menu{};
 	QProcess process;
-	bool wantConnectInfo;
-	bool wantInit;
-	bool runAsync;
+	bool wantConnectInfo{};
+	bool wantInit{};
+	bool runAsync{};
 	QList<QPair<QString, QString>> envir;
 };
 
@@ -57,7 +56,7 @@ void AddonManager::loadFromPath(const QString &path, QList<QPushButton*> &button
 	QFileInfoList fileInfoList = configDir.entryInfoList(QDir::Files, QDir::Name);
 	QRegularExpression paramRegex("^([A-Z]+)=(.*)$", QRegularExpression::MultilineOption);
 
-	for (QFileInfo fileInfo : fileInfoList) {
+	for (const auto& fileInfo : fileInfoList) {
 		QString filePath = fileInfo.absoluteFilePath();
 		QSettings setting(filePath, QSettings::IniFormat);
 		setting.setIniCodec("UTF-8");
@@ -77,7 +76,7 @@ void AddonManager::loadFromPath(const QString &path, QList<QPushButton*> &button
 		}
 
 		// Alloc addon
-		Addon *addon = new Addon();
+		auto *addon = new Addon();
 		// Toggle/click callback
 		auto toggleFun = [=](bool value) {
 			addon->envir.append(qMakePair(s_EVENT, s_clicked));
@@ -92,7 +91,7 @@ void AddonManager::loadFromPath(const QString &path, QList<QPushButton*> &button
 			addon->menu->setCheckable(checkable);
 			addon->menu->setToolTip(tooltip);
 			menuEntries.append(addon->menu);
-			addon->menu->connect(addon->menu, &QAction::triggered, toggleFun);
+			QObject::connect(addon->menu, &QAction::triggered, toggleFun);
 		} else if (type == "button") {
 			addon->button = new QPushButton(caption);
 			if (!icon.isNull()) {
@@ -103,7 +102,7 @@ void AddonManager::loadFromPath(const QString &path, QList<QPushButton*> &button
 			addon->button->setCheckable(checkable);
 			addon->button->setToolTip(tooltip);
 			buttons.append(addon->button);
-			addon->button->connect(addon->button, &QPushButton::clicked, toggleFun);
+			QObject::connect(addon->button, &QPushButton::clicked, toggleFun);
 		} else {
 			qDebug() << "Ignoring unknown addon type" << type;
 			delete addon;
@@ -117,13 +116,13 @@ void AddonManager::loadFromPath(const QString &path, QList<QPushButton*> &button
 		// Setup process
 		addon->process.setProgram(exec);
 		// Stdin for status updates
-		addon->process.connect(&addon->process, &QProcess::readyReadStandardOutput, [=]() {
+		QObject::connect(&addon->process, &QProcess::readyReadStandardOutput, [=]() {
 			auto lines = addon->process.readAllStandardOutput();
 			auto matches = paramRegex.globalMatch(lines);
 			handleAddonOutput(addon, matches);
 		});
 		// Stderr just for debugging
-		addon->process.connect(&addon->process, &QProcess::readyReadStandardError, [=]() {
+		QObject::connect(&addon->process, &QProcess::readyReadStandardError, [=]() {
 			qDebug() << exec << "stderr:" << QString::fromLocal8Bit(addon->process.readAllStandardError());
 		});
 	}
@@ -144,7 +143,7 @@ void AddonManager::initControls()
 
 void AddonManager::connectEvent(bool isLocal, const QString &address)
 {
-	for (auto addon : _addons) {
+	for (auto *addon : _addons) {
 		if (!addon->wantConnectInfo)
 			continue;
 		addon->envir.append(qMakePair(s_EVENT, s_connected));
@@ -168,7 +167,7 @@ static void executeAddon(Addon *addon)
 {
 	// Set up environment
 	auto env = QProcessEnvironment::systemEnvironment();
-	for (auto e : addon->envir) {
+	for (const auto& e : addon->envir) {
 		env.insert(e.first, e.second);
 	}
 	addon->envir.clear();
@@ -184,26 +183,26 @@ static void executeAddon(Addon *addon)
 	addon->process.setProcessEnvironment(env);
 	// Run
 	if (addon->runAsync) {
-		addon->process.startDetached(addon->process.program(), QStringList());
+		QProcess::startDetached(addon->process.program(), QStringList());
 	} else {
 		addon->process.start();
 		addon->process.closeWriteChannel();
 	}
 }
 
-static void setAddonVisible(Addon *addon, bool newValue)
+static void setAddonVisible(Addon *addon, bool visible)
 {
 	if (addon->button != nullptr) {
 		QWidget *p = addon->button->parentWidget();
 		bool wasVisible = p != nullptr && addon->button->isVisibleTo(p);
-		addon->button->setVisible(newValue);
-		if (p != nullptr && wasVisible != newValue) {
+		addon->button->setVisible(visible);
+		if (p != nullptr && wasVisible != visible) {
 			// Visibility changed -- adjust size of toolbar
-			int size = (addon->button->width() + 2) * (newValue ? 1 : -1);
+			int size = (addon->button->width() + 2) * (visible ? 1 : -1);
 			p->setFixedWidth(p->width() + size);
 		}
 	} else {
-		addon->menu->setVisible(newValue);
+		addon->menu->setVisible(visible);
 	}
 }
 
diff --git a/src/client/addons/addons.h b/src/client/addons/addons.h
index 185c399..6f39087 100644
--- a/src/client/addons/addons.h
+++ b/src/client/addons/addons.h
@@ -1,5 +1,5 @@
-#ifndef _ADDONS_H_
-#define _ADDONS_H_
+#ifndef PVS_ADDONS_H_
+#define PVS_ADDONS_H_
 
 #include <QString>
 #include <QList>
diff --git a/src/client/clientapp/clientapp.cpp b/src/client/clientapp/clientapp.cpp
index 8131e6f..2bc8fac 100644
--- a/src/client/clientapp/clientapp.cpp
+++ b/src/client/clientapp/clientapp.cpp
@@ -1,11 +1,18 @@
 #include "clientapp.h"
-#include <QNetworkInterface>
+
 #include "../connectwindow/connectwindow.h"
 #include "../toolbar/toolbar.h"
 #include "../net/serverconnection.h"
 
+#include <QNetworkInterface>
+#include <QTranslator>
+#include <QLibraryInfo>
+
 ClientApp::ClientApp(int& argc, char** argv)
-	: QApplication(argc, argv), _connectionMode(ConnectionMode::None), _examMode(false), _connection(nullptr), _isManagerPc(false)
+	: QApplication(argc, argv)
+	, _connectionMode(ConnectionMode::None)
+	, _examMode(false)
+	, _connection(nullptr)
 {
 	/* some values */
 	setOrganizationName("openslx");
@@ -21,24 +28,22 @@ ClientApp::ClientApp(int& argc, char** argv)
 
 	/* set translator */
 	// System strings
-	QTranslator *qtTranslator = new QTranslator(this);
+	auto *qtTranslator = new QTranslator(this);
 	if (!qtTranslator->load(QLocale::system(), "qt", "_", QLibraryInfo::location(QLibraryInfo::TranslationsPath))) {
 		qDebug() << "Could not load system string translations" << QLocale::system() << QLibraryInfo::location(QLibraryInfo::TranslationsPath);
 	} else {
 		installTranslator(qtTranslator);
 	}
 	// App specific
-	QTranslator *translator = new QTranslator(this);
+	auto *translator = new QTranslator(this);
 	if (!translator->load(QLocale::system(), ":/", "l_")) {
 		qDebug() << "Could not load app translations" << QLocale::system();
 	} else {
 		installTranslator(translator);
 	}
 
-	readIsManagerPc();
-
 	_connectWindow = new ConnectWindow(nullptr);
-	connect(_connectWindow, SIGNAL(connected(ServerConnection*)), this, SLOT(connected(ServerConnection*)));
+	connect(_connectWindow, &ConnectWindow::connected, this, &ClientApp::connected);
 	if (_connectionMode == ConnectionMode::Auto) {
 		_toolbar = new Toolbar(true); // auto connect client without session ID.
 	} else if (_connectionMode == ConnectionMode::Session) {
@@ -54,7 +59,7 @@ ClientApp::ClientApp(int& argc, char** argv)
 QStringList ClientApp::parseParameters()
 {
 	QStringList rest;
-	for (QString a : QApplication::arguments()) {
+	for (const QString &a : QApplication::arguments()) {
 		if (a == "--exam-mode") {
 			_examMode = true;
 		} else if (a == "--auto") {
@@ -79,7 +84,7 @@ QStringList ClientApp::arguments()
 QSharedPointer<QSettings> ClientApp::getSettings()
 {
 	QSharedPointer<QSettings> set;
-	if (_iniPath == "") {
+	if (_iniPath.isEmpty()) {
 		/* default location (system scope) */
 		set = QSharedPointer<QSettings>(new QSettings(QSettings::IniFormat, QSettings::SystemScope, "openslx/pvs2", "pvs2"));
 	} else {
@@ -90,32 +95,10 @@ QSharedPointer<QSettings> ClientApp::getSettings()
 	return set;
 }
 
-/* returns true when the pc of this client is also eligible to be a manager */
-void ClientApp::readIsManagerPc()
-{
-	QList<Room> myRooms;
-	auto conf = clientApp->getSettings();
-	QStringList roomNames = conf->value("rooms").toStringList();
-
-	/* go through all rooms and check if this client is a manager of the room. */
-	for (auto roomName : roomNames) {
-		conf->beginGroup(roomName);
-		const QString mgrIP = conf->value("mgrIP").toString();
-
-		foreach (const QHostAddress & address, QNetworkInterface::allAddresses()) {
-			if (address.toString()  == mgrIP) {
-				_isManagerPc = true;
-				return;
-			}
-		}
-		conf->endGroup();
-	}
-}
-
 void ClientApp::connected(ServerConnection* connection)
 {
 	_connection = connection;
-	connect(connection, SIGNAL(disconnected(ServerConnection*)), this, SLOT(disconnected(ServerConnection*)));
+	connect(_connection, &ServerConnection::disconnected, this, &ClientApp::disconnected);
 }
 
 void ClientApp::disconnected(ServerConnection* connection)
diff --git a/src/client/clientapp/clientapp.h b/src/client/clientapp/clientapp.h
index 91dccf3..0824683 100644
--- a/src/client/clientapp/clientapp.h
+++ b/src/client/clientapp/clientapp.h
@@ -9,7 +9,7 @@
 #if defined(clientApp)
 #undef clientApp
 #endif
-#define clientApp (static_cast<ClientApp*>(QCoreApplication::instance()))
+#define clientApp (static_cast<ClientApp*>(QCoreApplication::instance())) // NOLINT(cppcoreguidelines-pro-type-static-cast-downcast)
 
 class Toolbar;
 class ConnectWindow;
@@ -36,12 +36,9 @@ private:
 	ServerConnection* _connection;
 	QStringList _arguments;
 	QString _iniPath;
-	bool _isManagerPc;
 
 	QStringList parseParameters();
 
-	void readIsManagerPc();
-
 public:
 
 	ClientApp(int& argc, char** argv);
@@ -56,9 +53,7 @@ public:
 
 	ConnectWindow* connectWindow() const { return _connectWindow; }
 
-	bool isConfiguredAsManager() { return _isManagerPc; }
-
-	bool isConnectedToLocalManager() { return _connection != nullptr && _connection->isLocalConnection(); }
+	bool isConnectedToLocalManager() const { return _connection != nullptr && _connection->isLocalConnection(); }
 
 private slots:
 
diff --git a/src/client/connectwindow/connectwindow.cpp b/src/client/connectwindow/connectwindow.cpp
index 8c47eea..0bc6835 100644
--- a/src/client/connectwindow/connectwindow.cpp
+++ b/src/client/connectwindow/connectwindow.cpp
@@ -7,13 +7,14 @@
 
 #include <QNetworkInterface>
 #include "../../shared/settings.h"
-#include "../../shared/network.h"
 #include "../../shared/util.h"
 #include "../net/serverconnection.h"
 #include "../clientapp/clientapp.h"
 #include "connectwindow.h"
 #include "ui_connectwindow.h"
 
+#include <QCloseEvent>
+
 #define UDPBUFSIZ 9000
 #define SALT_LEN 18
 
@@ -43,17 +44,16 @@ ConnectWindow::ConnectWindow(QWidget *parent) :	QWidget(parent)
 	_ui->stackedWidget->setCurrentIndex(0);
 
 	// Set actions of buttons
-	connect(_ui->btn_connection, SIGNAL(clicked()), this, SLOT(onBtnConnection()));
-	connect(_ui->btn_hide, SIGNAL(clicked()), this, SLOT(onBtnHide()));
+	connect(_ui->btn_connection, &QPushButton::clicked, this, &ConnectWindow::onBtnConnection);
+	connect(_ui->btn_hide, &QPushButton::clicked, this, &ConnectWindow::onBtnHide);
 
-	connect(_ui->comboBox_rooms, SIGNAL(currentIndexChanged(int)), this, SLOT(onRoomSelection(int)));
+	connect(_ui->comboBox_rooms, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &ConnectWindow::onRoomSelection);
 
 	// React on discovery signal
-	connect(&_serverDiscovery, SIGNAL(serverDetected(QString, quint16, QByteArray, QByteArray, bool)),
-	        this, SLOT(onServerDetected(QString, quint16, QByteArray, QByteArray, bool)));
+	connect(&_serverDiscovery, &ServerDiscovery::serverDetected, this, &ConnectWindow::onServerDetected);
 
 	/* finally the most requested feature: connect on press of the enter key */
-	connect(_ui->lineEditName, SIGNAL(returnPressed()), _ui->btn_connection, SIGNAL(clicked()));
+	connect(_ui->lineEditName, &QLineEdit::returnPressed, this, &ConnectWindow::onBtnConnection);
 
 	/* by default don't show the manual connection box */
 	_ui->box_manual->setVisible(false);
@@ -64,7 +64,7 @@ ConnectWindow::ConnectWindow(QWidget *parent) :	QWidget(parent)
 /**
  * @brief ConnectWindow::~ConnectWindow
  */
-ConnectWindow::~ConnectWindow() {}
+ConnectWindow::~ConnectWindow() = default;
 
 
 
@@ -181,7 +181,7 @@ void ConnectWindow::showEvent(QShowEvent* /* event */ )
  *							if not --> connect to given sessionName.
  * @param sessionName
  */
-void ConnectWindow::connectToSession(const QByteArray sessionName, QString mgrIP)
+void ConnectWindow::connectToSession(const QByteArray& sessionName, const QString &mgrIP)
 {
 	if (_state != Idle)
 		return;
@@ -254,7 +254,7 @@ void ConnectWindow::onBtnConnection()
 /** set the available rooms.
  *  If the list of rooms is empty, switches automatically to the "manual
  *  connection" page */
-void ConnectWindow::setAvailableRooms(QList<Room> m)
+void ConnectWindow::setAvailableRooms(const QList<Room>& m)
 {
 	_ui->comboBox_rooms->clear();
 	foreach (Room r, m) {
@@ -298,9 +298,9 @@ void ConnectWindow::onRoomSelection(int index)
 void ConnectWindow::onServerDetected(const QString& host, const quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect)
 {
 	_pendingConnection = new ServerConnection(host, port, sessionName, certHash, autoConnect);
-	connect(_pendingConnection, SIGNAL(stateChange(ConnectWindow::ConnectionState)), this, SLOT(onConnectionStateChange(ConnectWindow::ConnectionState)));
-	connect(_pendingConnection, SIGNAL(destroyed(QObject*)), this, SLOT(onConnectionClosed(QObject*)));
-	connect(_pendingConnection, SIGNAL(disconnected(ServerConnection*)), this, SLOT(onConnectionDisconnected(ServerConnection*)));
+	connect(_pendingConnection, &ServerConnection::stateChange, this, &ConnectWindow::onConnectionStateChange);
+	connect(_pendingConnection, &ServerConnection::destroyed, this, &ConnectWindow::onConnectionClosed);
+	connect(_pendingConnection, &ServerConnection::disconnected, this, &ConnectWindow::onConnectionDisconnected);
 }
 
 
@@ -321,8 +321,8 @@ void ConnectWindow::onConnectionStateChange(ConnectWindow::ConnectionState state
 		_state = Scanning;
 	}
 	if (state == Connected) {
-		QObject::disconnect(_pendingConnection, SIGNAL(stateChange(ConnectWindow::ConnectionState)), this, SLOT(onConnectionStateChange(ConnectWindow::ConnectionState)));
-		QObject::disconnect(_pendingConnection, SIGNAL(destroyed(QObject*)), this, SLOT(onConnectionClosed(QObject*)));
+		QObject::disconnect(_pendingConnection, &ServerConnection::stateChange, this, &ConnectWindow::onConnectionStateChange);
+		QObject::disconnect(_pendingConnection, &ServerConnection::destroyed, this, &ConnectWindow::onConnectionClosed);
 		emit connected(_pendingConnection);
 		_pendingConnection = nullptr;
 		_timerHide = startTimer(2000);
diff --git a/src/client/connectwindow/connectwindow.h b/src/client/connectwindow/connectwindow.h
index 2df672d..4a0ae7d 100644
--- a/src/client/connectwindow/connectwindow.h
+++ b/src/client/connectwindow/connectwindow.h
@@ -16,7 +16,7 @@
 #ifndef PVSCONNECTWINDOW_H_
 #define PVSCONNECTWINDOW_H_
 
-#include <QtWidgets>
+#include <QWidget>
 #include <QMap>
 #include <QUdpSocket>
 #include <QSslSocket>
@@ -56,10 +56,10 @@ public:
 	};
 
 	explicit ConnectWindow(QWidget *parent = nullptr);
-	virtual ~ConnectWindow();
+	~ConnectWindow() override;
 
-	void connectToSession(const QByteArray sessionName, QString mgrIP);
-	void setAvailableRooms(QList<Room> m);
+	void connectToSession(const QByteArray& sessionName, const QString &mgrIP);
+	void setAvailableRooms(const QList<Room>& m);
 
 private:
 	Ui::ConnectWindow *_ui;
@@ -71,18 +71,17 @@ private:
 	QString           _currentIp;
 	QString           _defaultSessionName;
 	NetworkMessage    _packet;
-	bool              _tryReconnect;
+	bool              _tryReconnect{};
 	int               _timerHide;
 
 	void updateUserInterface();
 
 protected:
-	void timerEvent(QTimerEvent* event);
-	void closeEvent(QCloseEvent *e);
-	void showEvent(QShowEvent* event);
+	void timerEvent(QTimerEvent* event) override;
+	void closeEvent(QCloseEvent *e) override;
+	void showEvent(QShowEvent* event) override;
 
 protected slots:
-	void doShow();
 	void onBtnConnection();
 	void onBtnHide();
 
@@ -92,13 +91,15 @@ protected slots:
 	void onConnectionClosed(QObject* connection);
 	void onConnectionDisconnected(ServerConnection* connection);
 	//	void onUdpReadyRead();
-	void onServerDetected(const QString& host, const quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect);
+	void onServerDetected(const QString& host, quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect);
 
 public slots:
 	/** actually connects the connection **/
 	void DoConnect();
 	/** actually disconnects the connection **/
 	void DoDisconnect();
+
+	void doShow();
 signals:
 	void disconnect();
 	void connected(ServerConnection* connection);
diff --git a/src/client/informationdialog/informationdialog.cpp b/src/client/informationdialog/informationdialog.cpp
index fb3e87c..ff96641 100644
--- a/src/client/informationdialog/informationdialog.cpp
+++ b/src/client/informationdialog/informationdialog.cpp
@@ -1,19 +1,23 @@
 #include "informationdialog.h"
+
 #include <QNetworkInterface>
 #include <QHostInfo>
 #include <QDir>
 #include <QDirIterator>
+#include <QLayout>
+#include <QFormLayout>
+#include <QLabel>
 
 InformationDialog::InformationDialog()  : QDialog()
 {
 
 	/* widgets */
-	_lblTitle = new QLabel(tr("<h1>system information</h1>"));
-	_tableWidget = new QWidget();
+	_lblTitle = new QLabel(tr("<h1>system information</h1>"), this);
+	_tableWidget = new QWidget(this);
 
 	/* layouts */
-	_layout = new QVBoxLayout();
-	_tableLayout = new QFormLayout();
+	_layout = new QVBoxLayout(this);
+	_tableLayout = new QFormLayout(this);
 
 	/* */
 	_tableWidget->setLayout(_tableLayout);
@@ -30,11 +34,12 @@ void InformationDialog::initTable()
 {
 	/* NETWORK*/
 	/* hostnames */
-	_tableLayout->addRow(new QLabel("<b>" + tr("hostname") + "</b>"), new QLabel(QHostInfo::localHostName()));
+	_tableLayout->addRow(new QLabel("<b>" + tr("hostname") + "</b>", this),
+						 new QLabel(QHostInfo::localHostName(), this));
 	/* ips */
 	QStringList interfaceFilter;
 	QString bridgeDevicePath("/sys/devices/virtual/net/");
-	QDirIterator it(bridgeDevicePath, QStringList() << "brif", QDir::Dirs, QDirIterator::Subdirectories);
+	QDirIterator it(bridgeDevicePath, QStringList("brif"), QDir::Dirs, QDirIterator::Subdirectories);
 	while (it.hasNext()) {
 		it.next();
 		QDir dir = it.filePath();
@@ -42,16 +47,16 @@ void InformationDialog::initTable()
 		interfaceFilter += dir.entryList();
 	}
 
-	for (QNetworkInterface interface : QNetworkInterface::allInterfaces()) {
+	for (const auto& interface : QNetworkInterface::allInterfaces()) {
 
 		if (interfaceFilter.contains(interface.name()) || interface.flags().testFlag(QNetworkInterface::IsLoopBack)) {
 			qDebug() << "interface filtered: " << interface.name();
 			continue;
 		}
 
-		_tableLayout->addRow("<u><b>" + interface.name() + "</b></u>", new QLabel(""));
+		_tableLayout->addRow("<u><b>" + interface.name() + "</b></u>", new QLabel(this));
 
-		for (QNetworkAddressEntry entry : interface.addressEntries()) {
+		for (const auto &entry : interface.addressEntries()) {
 			QLabel* label;
 			QLabel* value;
 			QHostAddress hostAddr = entry.ip();
@@ -61,18 +66,17 @@ void InformationDialog::initTable()
 				continue;
 
 			if (hostAddr.protocol() == QAbstractSocket::IPv6Protocol)  {
-				label = new QLabel("IPv6");
-				value = new QLabel(hostAddr.toString().split("%").first());
+				label = new QLabel("IPv6", this);
+				value = new QLabel(hostAddr.toString().split("%").first(), this);
 			} else {
-				label = new QLabel("IPv4");
-				value = new QLabel(hostAddr.toString());
+				label = new QLabel("IPv4", this);
+				value = new QLabel(hostAddr.toString(), this);
 			}
 
 			_tableLayout->addRow(label, value);
 		}
-		_tableLayout->addRow("MAC", new QLabel(interface.hardwareAddress()));
+		_tableLayout->addRow("MAC", new QLabel(interface.hardwareAddress(), this));
 	}
 
 	/* TODO: Add other information */
-}
-
+}
\ No newline at end of file
diff --git a/src/client/informationdialog/informationdialog.h b/src/client/informationdialog/informationdialog.h
index 42aaa7b..f210dd8 100644
--- a/src/client/informationdialog/informationdialog.h
+++ b/src/client/informationdialog/informationdialog.h
@@ -1,12 +1,11 @@
 #ifndef INFORMATION_DIALOG_H
 #define INFORMATION_DIALOG_H
+
 #include <QDialog>
-#include <QLayout>
-#include <QFormLayout>
-#include <QLabel>
-#include <QDebug>
-#include <QStringList>
 
+class QLayout;
+class QFormLayout;
+class QLabel;
 
 class InformationDialog : public QDialog
 {
@@ -21,7 +20,7 @@ private:
 	void initTable();
 
 public:
-	InformationDialog();
+	explicit InformationDialog();
 
 };
 
diff --git a/src/client/main.cpp b/src/client/main.cpp
index eefd0d8..cb7aea6 100644
--- a/src/client/main.cpp
+++ b/src/client/main.cpp
@@ -9,19 +9,18 @@ int main(int argc, char** argv)
 {
 
 	ClientApp app(argc, argv);
-	qsrand(uint(QDateTime::currentMSecsSinceEpoch()));
 
 	/* here we handle the arguments that were not handled by ClientApp */
-	for (QString a : app.arguments()) {
+	for (const auto &a : app.arguments()) {
 		if (a == "--usage" || a == "--help") {
-			qStdout() << "Usage: pvsclient [--exam-mode] [--auto|--session=xxx|\"\"]" << endl;
+			qStdout() << "Usage: pvsclient [--exam-mode] [--auto|--session=xxx|\"\"]" << Qt::endl;
 			exit(0);
 		} else if (a.contains("pvsclient")) {
 			/* do nothing */
 		} else {
-			qStdout() << "Unknown argument: " << a << endl;
+			qStdout() << "Unknown argument: " << a << Qt::endl;
 			exit(1);
 		}
 	}
-	return app.exec();
+	return ClientApp::exec();
 }
diff --git a/src/client/net/serverconnection.cpp b/src/client/net/serverconnection.cpp
index ca19c76..e500528 100644
--- a/src/client/net/serverconnection.cpp
+++ b/src/client/net/serverconnection.cpp
@@ -1,21 +1,20 @@
 #include "serverconnection.h"
-#include <QtCore>
-#include <QPixmap>
-#include <QGuiApplication>
-#include <QHostInfo>
-#include <unistd.h>
-#include <cstdlib>
-#include <sys/types.h>
-#include <pwd.h>
 
-//#define verbose
 #include "../vnc/vncserver.h"
-
 #include "../../shared/util.h"
 #include "../../shared/settings.h"
 #include "../util/platform/blankscreen.h"
 #include "../clientapp/clientapp.h"
 
+#include <QPixmap>
+#include <QGuiApplication>
+#include <QHostInfo>
+#include <QScreen>
+// For getting logged-in username
+#include <sys/types.h>
+#include <pwd.h>
+#include <unistd.h>
+
 #define CHALLENGE_LEN 20
 
 ServerConnection::ServerConnection(const QString& host, const quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect) :
@@ -23,16 +22,13 @@ ServerConnection::ServerConnection(const QString& host, const quint16 port, cons
 {
 	_socket = new QSslSocket();
 	_blank = new BlankScreen();
-	connect(_socket, SIGNAL(encrypted()), this, SLOT(sock_connected()));
-	connect(_socket, SIGNAL(readyRead()), this, SLOT(sock_dataArrival()));
-	connect(_socket, SIGNAL(disconnected()), this, SLOT(sock_closed()));
-	connect(_socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(sock_error(QAbstractSocket::SocketError)));
-	connect(_socket,
-	        SIGNAL(sslErrors(const QList<QSslError> &)),
-	        this,
-	        SLOT(sslErrors(const QList<QSslError> &))
+	connect(_socket, &QSslSocket::encrypted, this, &ServerConnection::sock_connected);
+	connect(_socket, &QSslSocket::readyRead, this, &ServerConnection::sock_dataArrival);
+	connect(_socket, &QSslSocket::disconnected, this, &ServerConnection::sock_closed);
+	connect(_socket, &QSslSocket::errorOccurred, this, &ServerConnection::sock_error);
+	connect(_socket, QOverload<const QList<QSslError> &>::of(&QSslSocket::sslErrors),
+	        this, &ServerConnection::sslErrors
 	       );
-	connect(_socket, &QSslSocket::peerVerifyError, [=](const QSslError &error) { qDebug() << "PVE:" << error.errorString(); });
 	qDebug("Connecting to %s on port %d", host.toUtf8().data(), int(port));
 	_socket->ignoreSslErrors();
 	_socket->connectToHostEncrypted(host, port);
@@ -40,7 +36,7 @@ ServerConnection::ServerConnection(const QString& host, const quint16 port, cons
 	_lastData = QDateTime::currentMSecsSinceEpoch() + PING_TIMEOUT_MS;
 	_timerConnectionCheck = startTimer(5000);
 	// Connect the vnc start/stop signal to this class, so we can tell the server about successful vnc server startup
-	connect(VncServer::instance(), SIGNAL(started(int, QString&, QString&)), this, SLOT(onVncServerStartStop(int, QString&, QString&)));
+	connect(VncServer::instance(), &VncServer::started, this, &ServerConnection::onVncServerStartStop);
 }
 
 ServerConnection::~ServerConnection()
@@ -112,7 +108,7 @@ void ServerConnection::handleMsg()
 			emit stateChange(ConnectWindow::AwaitingChallengeResponse);
 			_myChallenge.resize(CHALLENGE_LEN);
 			for (int i = 0; i < CHALLENGE_LEN; ++i) {
-				_myChallenge[i] = char(qrand() & 0xff);
+				_myChallenge[i] = char(slxrand() & 0xff);
 			}
 			QByteArray serverChallenge(_fromServer.getFieldBytes(_CHALLENGE));
 			_toServer.reset();
@@ -320,7 +316,7 @@ void ServerConnection::timerEvent(QTimerEvent *event)
  * server was succesfully started, or was terminated (either planned or
  * crashed).
  */
-void ServerConnection::onVncServerStartStop(int port, QString& ropass, QString& rwpass)
+void ServerConnection::onVncServerStartStop(int port, const QString &ropass, const QString &rwpass)
 {
 	_toServer.reset();
 	_toServer.setField(_ID, _VNCSERVER);
@@ -357,9 +353,8 @@ void ServerConnection::onVncViewerStartStop(const bool started, const int client
 void ServerConnection::sslErrors(const QList<QSslError> & errors)
 {
 	_socket->ignoreSslErrors();
-	for (QList<QSslError>::const_iterator it = errors.begin(); it != errors.end(); it++) {
-		const QSslError &err = *it;
-		qDebug("Connect SSL: %s", qPrintable(err.errorString()));
+	for (const auto &err : errors) {
+			qDebug("Connect SSL: %s", qPrintable(err.errorString()));
 		if (err.error() == QSslError::HostNameMismatch)
 			continue; // We don't pay attention to hostnames for validation
 		if (err.error() == QSslError::SelfSignedCertificate)
diff --git a/src/client/net/serverconnection.h b/src/client/net/serverconnection.h
index f5f6264..f434f0b 100644
--- a/src/client/net/serverconnection.h
+++ b/src/client/net/serverconnection.h
@@ -33,18 +33,15 @@ private:
 	void checkLocalConnection();
 
 public:
-	ServerConnection(const QString& host, const quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect);
+	ServerConnection(const QString& host, quint16 port, const QByteArray& sessionName, const QByteArray& certHash, bool autoConnect);
 	void disconnectFromServer();
-	~ServerConnection();
+	~ServerConnection() override;
 	inline bool isConnected() const
 	{
 		return _socket != nullptr && _socket->state() == QAbstractSocket::ConnectedState;
 	}
 
-	const inline QString getPeerAdress() const
-	{
-		return _socket->peerAddress().toString();
-	}
+	QString getPeerAdress() const { return _socket->peerAddress().toString(); }
 
 	bool isLocalConnection() {
 		if (_isLocalConnection == -1) {
@@ -57,7 +54,7 @@ public:
 	void sendAttention(bool on);
 
 protected:
-	void timerEvent(QTimerEvent *event);
+	void timerEvent(QTimerEvent *event) override;
 
 private slots:
 	void sslErrors(const QList<QSslError> & errors); // triggered for errors that occur during SSL negotiation
@@ -66,9 +63,10 @@ private slots:
 	void sock_error(QAbstractSocket::SocketError errcode); // triggered if an error occurs on the socket
 	void sock_connected(); // triggered if the connection is established and ready to use
 
-	void onVncServerStartStop(int port, QString& ropass, QString& rwpass); // triggered if the local vnc server was started
+	void onVncServerStartStop(int port, const QString &ropass, const QString &rwpass); // triggered if the local vnc server was started
 
-	void onVncViewerStartStop(const bool started, const int clientId);
+public slots:
+	void onVncViewerStartStop(bool started, int clientId);
 
 signals:
 	void openVnc(const QString& host, int port, const QString& passwd, bool ro, bool fullscreen, const QString& caption, const int clientId, const QByteArray& rawThumb);
diff --git a/src/client/net/serverdiscovery.cpp b/src/client/net/serverdiscovery.cpp
index b2d7605..efae165 100644
--- a/src/client/net/serverdiscovery.cpp
+++ b/src/client/net/serverdiscovery.cpp
@@ -4,8 +4,7 @@
 #include "../../shared/network.h"
 #include "../../shared/util.h"
 #include "serverdiscovery.h"
-#include <assert.h>
-
+#include "../util/util.h"
 
 /**
  * Ctor
@@ -21,33 +20,31 @@ ServerDiscovery::ServerDiscovery(QObject *parent)
 	/* Try to get a UDP port for server discovery */
 	int tries = 10;
 	while (tries-- != 0) {
-		quint16 port = quint16(16384 + qrand() % 32768);
+		quint16 port = quint16(16384 + slxrand() % 32768);
 		if (_discoverySocket.bind(QHostAddress::AnyIPv4, port))
 			break;
 		if (tries == 0)
 			qFatal("Could not bind to any UDP port for server discovery.");
 	}
 	// Handle incoming messages
-	connect(&_discoverySocket, SIGNAL(readyRead()), this, SLOT(onUdpReadyRead()));
+	connect(&_discoverySocket, &QUdpSocket::readyRead, this, &ServerDiscovery::onUdpReadyRead);
 
 	/* Setup the discovery timer */
 	_discoveryTimer.setInterval(_minDiscoveryInterval);
 	_discoveryTimer.setSingleShot(true);
 	//
-	connect(&_discoveryTimer, SIGNAL(timeout()), this, SLOT(doDiscovery()));
+	connect(&_discoveryTimer, &QTimer::timeout, this, &ServerDiscovery::doDiscovery);
 }
 
 /**
  * Dtor
  */
-ServerDiscovery::~ServerDiscovery()
-{
-}
+ServerDiscovery::~ServerDiscovery() = default;
 
 /**
  * @brief start
  */
-void ServerDiscovery::start(const QByteArray& sessionName, QString mgrIP)
+void ServerDiscovery::start(const QByteArray& sessionName, const QString& mgrIP)
 {
 	if (!mgrIP.isEmpty()) {
 		_mgrIP.setAddress(mgrIP);
@@ -98,8 +95,8 @@ void ServerDiscovery::doDiscovery()
 	if (_salt2.size() < SALT_LEN)
 		_salt2.resize(SALT_LEN);
 	for (int i = 0; i < SALT_LEN; ++i) {
-		salt1[i] = char(qrand() & 0xff);
-		_salt2[i] = char(qrand() & 0xff);
+		salt1[i] = char(slxrand() & 0xff);
+		_salt2[i] = char(slxrand() & 0xff);
 	}
 	_packet.reset();
 	_packet.setField(_HASH, genSha1(&_nameBytes, &salt1, &iplist));
@@ -141,7 +138,7 @@ void ServerDiscovery::onUdpReadyRead()
 {
 	char data[UDPBUFSIZ];
 	QHostAddress addr;
-	quint16 port;
+	quint16 peerPort;
 	while (_discoverySocket.hasPendingDatagrams()) {
 		// Discard any packets if discovery is stopped
 		if (!this->isActive()) {
@@ -149,7 +146,7 @@ void ServerDiscovery::onUdpReadyRead()
 			continue;
 		}
 
-		const qint64 size = _discoverySocket.readDatagram(data, UDPBUFSIZ, &addr, &port);
+		const qint64 size = _discoverySocket.readDatagram(data, UDPBUFSIZ, &addr, &peerPort);
 		if (size <= 0) //|| clientApp->connection() != nullptr) // TODO CHECK
 			continue;
 
diff --git a/src/client/net/serverdiscovery.h b/src/client/net/serverdiscovery.h
index d7d6010..21f9bf9 100644
--- a/src/client/net/serverdiscovery.h
+++ b/src/client/net/serverdiscovery.h
@@ -17,10 +17,10 @@ public:
 	    InvalidHash
 	};
 
-	explicit ServerDiscovery(QObject *parent = 0);
-	~ServerDiscovery();
+	explicit ServerDiscovery(QObject *parent = nullptr);
+	~ServerDiscovery() override;
 
-	void start(const QByteArray& sessionName, QString mgrIP);
+	void start(const QByteArray& sessionName, const QString& mgrIP);
 	void stop();
 	inline bool isActive() { return _discoveryTimer.isActive(); }
 
diff --git a/src/client/toolbar/toolbar.cpp b/src/client/toolbar/toolbar.cpp
index 880e24f..bd5d689 100644
--- a/src/client/toolbar/toolbar.cpp
+++ b/src/client/toolbar/toolbar.cpp
@@ -2,7 +2,6 @@
 #include "../net/serverconnection.h"
 #include "../vnc/vncwindow.h"
 #include "../vnc/vncserver.h"
-#include "../util/util.h"
 #include "../informationdialog/informationdialog.h"
 #include "../clientapp/clientapp.h"
 #include "../addons/addons.h"
@@ -10,9 +9,11 @@
 #include "toolbar.h"
 #include "ui_toolbar.h"
 
-#include <QtAlgorithms>
 #include <QNetworkInterface>
-#include <QProcess>
+#include <QScreen>
+#include <QMenu>
+#include <QMouseEvent>
+#include <QMessageBox>
 
 /**
  * @brief
@@ -24,8 +25,13 @@
  * another widget, this widget becomes a child window inside parent. The new
  * widget is deleted when its parent is deleted.
  */
-Toolbar::Toolbar(const QByteArray sessionName, QWidget *parent)
-	: QWidget(parent), _showTimer(this), _hideTimer(this), _hideCountdown(10), _blinkTimer(this), _beWatchedEye(":eye")
+Toolbar::Toolbar(const QByteArray& sessionName, QWidget *parent)
+	: QWidget(parent)
+    , _showTimer(this)
+    , _hideTimer(this)
+    , _hideCountdown(10)
+    , _blinkTimer(this)
+    , _beWatchedEye(":eye")
 {
 	qDebug() << "sessionName - constructor";
 	init();
@@ -44,7 +50,12 @@ Toolbar::Toolbar(const QByteArray sessionName, QWidget *parent)
  * widget is deleted when its parent is deleted.
  */
 Toolbar::Toolbar(const bool autoConnect, QWidget *parent)
-	: QWidget(parent), _showTimer(this), _hideTimer(this), _hideCountdown(10), _blinkTimer(this), _beWatchedEye(":eye")
+	: QWidget(parent)
+    , _showTimer(this)
+    , _hideTimer(this)
+    , _hideCountdown(10)
+    , _blinkTimer(this)
+    , _beWatchedEye(":eye")
 {
 	qDebug() << "auto - constructor!";
 	init();
@@ -100,9 +111,9 @@ void Toolbar::init()
 	/* Create the connect window */
 	clientApp->connectWindow()->setAvailableRooms(myRooms());
 	// Connect the signals
-	connect(clientApp->connectWindow(), SIGNAL(disconnect()), this, SLOT(onDoDisconnect()));
-	connect(clientApp->connectWindow(), SIGNAL(connected(ServerConnection*)), this, SLOT(onConnected(ServerConnection*)));
-	connect(_ui->btnAttention, SIGNAL(toggled(bool)), this, SLOT(onBtnAttention()));
+	connect(clientApp->connectWindow(), &ConnectWindow::disconnect, this, &Toolbar::onDoDisconnect);
+	connect(clientApp->connectWindow(), &ConnectWindow::connected, this, &Toolbar::onConnected);
+	connect(_ui->btnAttention, &QToolButton::toggled, this, &Toolbar::onBtnAttention);
 
 	/* Setup menu */
 	initButtonsAndMenus();
@@ -112,7 +123,7 @@ void Toolbar::init()
 	_ui->btnAttention->setMaximumWidth(30);
 
 	/* Connect the signals from vnc server */
-	connect(VncServer::instance(), SIGNAL(started(int, QString&, QString&)), this, SLOT(onVncServerIsRunning(int)));
+	connect(VncServer::instance(), &VncServer::started, this, &Toolbar::onVncServerIsRunning);
 
 	/* React to screen geometry change */
 	connect(QGuiApplication::primaryScreen(), &QScreen::availableGeometryChanged, this, &Toolbar::setToolbarPosition);
@@ -124,10 +135,10 @@ void Toolbar::init()
 	/* Setup show & hide timer */
 	_showTimer.setInterval(500);
 	_showTimer.setSingleShot(true);
-	connect(&_showTimer, SIGNAL(timeout()), this, SLOT(showBar()));
+	connect(&_showTimer, &QTimer::timeout, this, &Toolbar::showBar);
 	_hideTimer.setInterval(50);
 	_hideTimer.setSingleShot(false);
-	connect(&_hideTimer, SIGNAL(timeout()), this, SLOT(hideBar()));
+	connect(&_hideTimer, &QTimer::timeout, this, &Toolbar::hideBar);
 
 	setVisible(true);
 	raise();
@@ -135,11 +146,11 @@ void Toolbar::init()
 
 	/* Setup blink timer */
 	_blinkTimer.setInterval(500);
-	connect(&_blinkTimer, SIGNAL(timeout()), this, SLOT(cameraBlink()));
+	connect(&_blinkTimer, &QTimer::timeout, this, &Toolbar::cameraBlink);
 }
 
 static QFrame* makeVerticalLine() {
-	QFrame *f = new QFrame();
+	auto *f = new QFrame();
 	f->setFrameShape(QFrame::HLine);
 	f->setFrameShadow(QFrame::Sunken);
 	return f;
@@ -191,12 +202,12 @@ void Toolbar::initButtonsAndMenus()
 	_acnQuit->setVisible(allow);
 
 	// Connect the signals
-	connect(_menu, SIGNAL(aboutToHide()), this, SLOT(delayedHideBar()));
-	connect(_acnConnect, SIGNAL(triggered()), clientApp->connectWindow(), SLOT(doShow()));
-	connect(_acnDisconnect, SIGNAL(triggered()), clientApp->connectWindow(), SLOT(DoDisconnect()));
-	connect(_acnInformation, SIGNAL(triggered()), this, SLOT(showInformationDialog()));
-	connect(_acnAbout, SIGNAL(triggered()), this, SLOT(showAboutDialog()));
-	connect(_acnQuit, SIGNAL(triggered()), this, SLOT(exit()));
+	connect(_menu, &QMenu::aboutToHide, this, &Toolbar::delayedHideBar);
+	connect(_acnConnect, &QAction::triggered, clientApp->connectWindow(), &ConnectWindow::doShow);
+	connect(_acnDisconnect, &QAction::triggered, clientApp->connectWindow(), &ConnectWindow::DoDisconnect);
+	connect(_acnInformation, &QAction::triggered, this, &Toolbar::showInformationDialog);
+	connect(_acnAbout, &QAction::triggered, this, &Toolbar::showAboutDialog);
+	connect(_acnQuit, &QAction::triggered, this, &Toolbar::exit);
 
 	// Delay until bar is visible
 	QTimer::singleShot(10, [=]() {
@@ -363,7 +374,7 @@ void Toolbar::onVncServerIsRunning(int port)
 void Toolbar::onDisconnected(ServerConnection* connection)
 {
 	if (connection != nullptr) {
-		disconnect(connection, SIGNAL(disconnected(ServerConnection*)), this, SLOT(onDisconnected(ServerConnection*)));
+		disconnect(connection, &ServerConnection::disconnected, this, &Toolbar::onDisconnected);
 	}
 	_ui->lblStatus->setStyleSheet("color:red");
 	_ui->lblStatus->setText(tr("Offline"));
@@ -394,12 +405,12 @@ void Toolbar::onConnected(ServerConnection* connection)
 	_ui->btnAttention->setVisible(true);
 	AddonManager::connectEvent(connection->isLocalConnection(), connection->getPeerAdress());
 	//
-	connect(connection, SIGNAL(disconnected(ServerConnection*)), this, SLOT(onDisconnected(ServerConnection*)));
-	connect(connection, SIGNAL(openVnc(const QString&, int, const QString&, bool, bool, const QString&, const int, const QByteArray&)),
-	        _vnc, SLOT(open(const QString&, int, const QString&, bool, bool, const QString&, const int, const QByteArray&)));
-	connect(connection, SIGNAL(closeVnc()), _vnc, SLOT(close()));
-	connect(connection, SIGNAL(attentionChanged(const bool)), this, SLOT(onServerAttentionChanged(const bool)));
-	connect(_vnc, SIGNAL(running(const bool, const int)), connection, SLOT(onVncViewerStartStop(const bool, const int)));
+	connect(connection, &ServerConnection::disconnected, this, &Toolbar::onDisconnected);
+	connect(connection, &ServerConnection::openVnc,
+	        _vnc, &VncWindow::open);
+	connect(connection, &ServerConnection::closeVnc, _vnc, &VncWindow::close);
+	connect(connection, &ServerConnection::attentionChanged, this, &Toolbar::onServerAttentionChanged);
+	connect(_vnc, &VncWindow::running, connection, &ServerConnection::onVncViewerStartStop);
 }
 
 /**
@@ -489,7 +500,7 @@ void Toolbar::showAboutDialog()
 
 void Toolbar::showInformationDialog()
 {
-	InformationDialog* d = new InformationDialog();
+	auto* d = new InformationDialog();
 	d->exec();
 	d->deleteLater();
 }
diff --git a/src/client/toolbar/toolbar.h b/src/client/toolbar/toolbar.h
index 48fbf03..702bae2 100644
--- a/src/client/toolbar/toolbar.h
+++ b/src/client/toolbar/toolbar.h
@@ -14,13 +14,15 @@
 #ifndef PVSCLIENTGUI_H_
 #define PVSCLIENTGUI_H_
 
-#include <QtWidgets>
+#include <QWidget>
+#include <QTimer>
 #include "../util/room.h"
 
 class ServerConnection;
 class VncWindow;
 class BlankScreen;
 
+class QMenu;
 
 namespace Ui
 {
@@ -32,47 +34,43 @@ class Toolbar : public QWidget
 	Q_OBJECT
 
 public:
-	Toolbar(QWidget *parent = 0);
-	Toolbar(const QByteArray sessionName, QWidget *parent = 0);
-	Toolbar(const bool autoConnect, QWidget *parent = 0);
-	virtual ~Toolbar();
+	explicit Toolbar(QWidget *parent = nullptr);
+	explicit Toolbar(const QByteArray& sessionName, QWidget *parent = nullptr);
+	explicit Toolbar(bool autoConnect, QWidget *parent = nullptr);
+	~Toolbar() override;
 
 private:
-	Ui::Toolbar *_ui;
-	QMenu *_menu;
-	QAction *_acnDisconnect;
-	QAction *_acnConnect;
-	QAction *_acnInformation;
-	QAction *_acnAbout;
-	QAction *_acnQuit;
+	Ui::Toolbar *_ui{};
+	QMenu *_menu{};
+	QAction *_acnDisconnect{};
+	QAction *_acnConnect{};
+	QAction *_acnInformation{};
+	QAction *_acnAbout{};
+	QAction *_acnQuit{};
 	QTimer _showTimer;
 	QTimer _hideTimer;
 	int _hideCountdown;
 	QTimer _blinkTimer;
-	VncWindow *_vnc;
-	bool _isManagerPc;
+	VncWindow *_vnc{};
 	const QPixmap _cam32, _beWatchedEye;
 	QPoint _lastDragPos;
 
-	int _yPos;
-	int _yPosHidden;
+	int _yPos{};
+	int _yPosHidden{};
 
 	void enterEvent(QEvent* e) override;
 	void mousePressEvent(QMouseEvent* event) override;
 	void mouseMoveEvent(QMouseEvent* event) override;
-	QList<Room> myRooms();
-	bool isManagerPc();
-	QString identifyMgrIP();
+	static QList<Room> myRooms();
+	static QString identifyMgrIP();
 	void init();
 	void initButtonsAndMenus();
 
-	QProcess lockDesktopP;
-
 private slots:
 	void onVncServerIsRunning(int port);
 	void onDisconnected(ServerConnection* connection);
 	void onConnected(ServerConnection* connection);
-	void onServerAttentionChanged(const bool on);
+	void onServerAttentionChanged(bool on);
 	void onDoDisconnect();
 	void onBtnAttention();
 	void exit();
diff --git a/src/client/util/platform/blankscreen.cpp b/src/client/util/platform/blankscreen.cpp
index 5f9b04b..a4c7d30 100644
--- a/src/client/util/platform/blankscreen.cpp
+++ b/src/client/util/platform/blankscreen.cpp
@@ -7,10 +7,6 @@
 #include <QTimer>
 
 #include <X11/Xlib.h>
-#include <X11/cursorfont.h>
-
-#include <cassert>
-#include <cstring>
 
 struct BlankScreen_Sysdep {
 	Display *dpy;
@@ -27,8 +23,8 @@ BlankScreen::BlankScreen() : QDialog(nullptr)
 	setStyleSheet("background-color:#000");
 
 	_locked = false;
-	QTimer *upper = new QTimer(this);
-	connect(upper, SIGNAL(timeout()), this, SLOT(timer_moveToTop()));
+	auto *upper = new QTimer(this);
+	connect(upper, &QTimer::timeout, this, &BlankScreen::timer_moveToTop);
 	upper->start(1111);
 }
 
diff --git a/src/client/util/room.h b/src/client/util/room.h
index 86939f7..46f8c02 100644
--- a/src/client/util/room.h
+++ b/src/client/util/room.h
@@ -1,11 +1,13 @@
 #ifndef ROOM_H
 #define ROOM_H
 
+#include <QDebug>
+
 struct Room {
 	QString mgr;
 	QString name;
 	int priority;
-	Room (QString _name, QString _mgr, int _priority)
+	Room (const QString &_name, const QString &_mgr, int _priority)
 	{
 		mgr = _mgr;
 		name = _name;
@@ -13,7 +15,7 @@ struct Room {
 	};
 };
 
-inline QDebug operator<<(QDebug debug, const Room& r)
+inline QDebug& operator<<(QDebug& debug, const Room& r)
 {
 	debug << r.name << "{mgr=" << r.mgr << ",prio=" << r.priority << "}";
 	return debug;
diff --git a/src/client/util/util.h b/src/client/util/util.h
index 89b19f4..e7a5ac9 100644
--- a/src/client/util/util.h
+++ b/src/client/util/util.h
@@ -1,10 +1,9 @@
-#ifndef UTIL_H_
-#define UTIL_H_
+#ifndef PVS_UTIL_H_
+#define PVS_UTIL_H_
 
 #include <QDir>
 #include <QTextStream>
 
-
 namespace Util
 {
 //#
@@ -22,4 +21,4 @@ inline QTextStream& qStdout()
 }
 
 
-#endif /* UTIL_H_ */
+#endif /* PVS_UTIL_H_ */
diff --git a/src/client/vnc/vncserver.cpp b/src/client/vnc/vncserver.cpp
index d819668..4c2363e 100644
--- a/src/client/vnc/vncserver.cpp
+++ b/src/client/vnc/vncserver.cpp
@@ -6,11 +6,12 @@
  */
 
 
-#include <QApplication>
+#include <QGuiApplication>
 #include <QProcess>
-#include <QDesktopWidget>
+#include <QScreen>
 #include "vncserver.h"
 #include "../util/util.h"
+#include "../../shared/util.h"
 
 VncServer* VncServer::me = nullptr;
 
@@ -34,7 +35,7 @@ static QString makePassword(int len = 10)
 {
 	QString ret(len, Qt::Uninitialized);
 	for (int i = 0; i < len; ++i)
-		ret[i] = QChar(43 + qrand() % 80);
+		ret[i] = QChar(43 + slxrand() % 80);
 	return ret;
 }
 
@@ -53,7 +54,7 @@ VncServer::VncServer() : _process(nullptr), _port(0), _timerId(0) {}
 /**
  * @brief VncServer::~VncServer
  */
-VncServer::~VncServer() {}
+VncServer::~VncServer() = default;
 
 QSharedPointer<QFile> VncServer::createPwFile(const QDir& dir)
 {
@@ -74,8 +75,8 @@ void VncServer::start()
 {
 	// Keep things clean
 	if (_process != nullptr) {
-		disconnect(_process, SIGNAL(error(QProcess::ProcessError)), this, SLOT(onError(QProcess::ProcessError)));
-		disconnect(_process, SIGNAL(finished(int)), this, SLOT(onFinished(int)));
+		_process->blockSignals(true);
+		_process->kill();
 	}
 	this->stop();
 	// Generate passwords
@@ -99,22 +100,22 @@ void VncServer::start()
 	pwhandle->close();
 	// Create new process
 	_process = new QProcess(this);
-	connect(_process, SIGNAL(readyReadStandardOutput()), this, SLOT(onStdOut()));
-	connect(_process, SIGNAL(readyReadStandardError()), this, SLOT(onStdErr()));
-	connect(_process, SIGNAL(error(QProcess::ProcessError)), this, SLOT(onError(QProcess::ProcessError)));
-	connect(_process, SIGNAL(finished(int)), this, SLOT(onFinished(int)));
+	connect(_process, &QProcess::readyReadStandardOutput, this, &VncServer::onStdOut);
+	connect(_process, &QProcess::readyReadStandardError, this, &VncServer::onStdErr);
+	connect(_process, &QProcess::errorOccurred, this, &VncServer::onError);
+	connect(_process,  QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
+			this, &VncServer::onFinished);
 	_timerId = startTimer(4000);
 	QStringList args;
 	args << "-forever";
 	args << "-display" << ":0";
-	args << "-passwdfile" << (QString("rm:" + pwhandle->fileName()));
+	args << "-passwdfile" << (QStringLiteral("rm:") + pwhandle->fileName());
 	args << "-shared";
 	args << "-repeat";
 	args << "-autoport" << QString::number(54112);
 
 	// Get rect of primary screen
-	const QDesktopWidget desktop;
-	const QRect primaryRect = desktop.screenGeometry();
+    const QRect primaryRect = QGuiApplication::primaryScreen()->geometry();
 
 	// Tell x11vnc to just use primary screen
 	args << "-clip";
@@ -141,8 +142,8 @@ void VncServer::stop()
 	if (_process == nullptr)
 		return;
 	qDebug("Stopping old VNC server.");
-	disconnect(_process, SIGNAL(readyReadStandardOutput()), this, SLOT(onStdOut()));
-	disconnect(_process, SIGNAL(readyReadStandardError()), this, SLOT(onStdErr()));
+	disconnect(_process, &QProcess::readyReadStandardOutput, this, &VncServer::onStdOut);
+	disconnect(_process, &QProcess::readyReadStandardError, this, &VncServer::onStdErr);
 	QProcess *process = _process;
 	_process = nullptr;
 	_port = 0;
@@ -215,7 +216,7 @@ void VncServer::onStdErr()
 		qDebug("VncServer::onStdErr() called in bad state.");
 		return;
 	}
-	QByteArray data(_process->readAllStandardError());
+	_process->readAllStandardError(); // Throw away
 }
 
 /**
@@ -232,7 +233,7 @@ void VncServer::onError(QProcess::ProcessError /* error */ )
  * @brief VncServer::onFinished
  * @param exitCode
  */
-void VncServer::onFinished(int /* exitCode */ )
+void VncServer::onFinished(int /* exitCode */, QProcess::ExitStatus /* exitStatus */)
 {
 	this->stop();
 	emit started(0, _ropass, _rwpass);
diff --git a/src/client/vnc/vncserver.h b/src/client/vnc/vncserver.h
index 4974946..1e71e2e 100644
--- a/src/client/vnc/vncserver.h
+++ b/src/client/vnc/vncserver.h
@@ -25,29 +25,29 @@ private:
 	int _timerId;
 
 	VncServer();
-	virtual ~VncServer();
-	QSharedPointer<QFile> createPwFile(const QDir& dir);
+	~VncServer() override;
+	static QSharedPointer<QFile> createPwFile(const QDir& dir);
 
 	static VncServer *me;
 
 public:
 	static VncServer *instance();
 
-	inline bool isVncServerRunning() { return _port > 0; }
+	inline bool isVncServerRunning() const { return _port > 0; }
 	void start();
 	void stop();
 
 protected:
-	void timerEvent(QTimerEvent *event);
+	void timerEvent(QTimerEvent *event) override;
 
 signals:
 	// Emited when started succesfully, or if startup failed. port will be <= 0 if it failed.
-	void started(int port, QString& ropass, QString& rwpass);
+	void started(int port, const QString& ropass, const QString& rwpass);
 
 private slots:
 	void onStdOut();
 	void onStdErr();
-	void onFinished(int exitCode);
+	void onFinished(int exitCode, QProcess::ExitStatus exitStatus);
 	void onError(QProcess::ProcessError error);
 
 };
diff --git a/src/client/vnc/vncthread.cpp b/src/client/vnc/vncthread.cpp
index 1a903d5..0e98cfe 100644
--- a/src/client/vnc/vncthread.cpp
+++ b/src/client/vnc/vncthread.cpp
@@ -17,8 +17,10 @@
  */
 
 #include "vncthread.h"
-#include <QPainter>
+#include "../../shared/util.h"
 
+#include <QPainter>
+#include <utility>
 #include <netinet/tcp.h>
 
 /**
@@ -29,15 +31,15 @@
  * @param passwd The password of the VNC server
  * @param quality The desired quality level for the VNC stream
  */
-VncThread::VncThread(QString host, int port, QString passwd, int quality) :
-	QThread(), _run(true), _started(false)
+VncThread::VncThread(QString host, int port, QString passwd, int quality)
+		: QThread()
+		, _host(std::move(host))
+		, _port(port)
+		, _passwd(std::move(passwd))
+		, _quality(quality)
+		, _run(true)
+		, _started(false)
 {
-	_host = host;
-	_port = port;
-	_passwd = passwd;
-	_quality = quality;
-	_client = nullptr;
-	_connected = false;
 	moveToThread(this);
 }
 
@@ -74,7 +76,7 @@ void VncThread::run()
 
 	// setup network
 	for (int retry = 0; retry < 5 && _run; ++retry) {
-		this->msleep(1 + qrand() % 60);
+		msleep(1 + slxrand() % 60);
 		if (!_run)
 			break;
 		_client = rfbGetClient(8, 3, 4);
@@ -100,7 +102,7 @@ void VncThread::run()
 		if (!_run)
 			break;
 		// error, let's try again
-		this->msleep(10 + qrand() % 50);
+		msleep(10 + slxrand() % 50);
 	}
 	if (_client != nullptr) {
 		qDebug("[%s] Connection successful!", metaObject()->className());
@@ -125,7 +127,7 @@ void VncThread::run()
 	_connected = false;
 	emit projectionStopped();
 	while (_run)
-		this->msleep(100);
+		msleep(100);
 	qDebug("[%s] VNC client stopped.", metaObject()->className());
 }
 
@@ -134,10 +136,10 @@ void VncThread::run()
  *
  * @return Name of the remote desktop
  */
-const QString VncThread::getDesktopName() const
+QString VncThread::getDesktopName() const
 {
 	if (_client == nullptr || _client->desktopName == nullptr)
-		return QString();
+		return {};
 	return QString(_client->desktopName);
 }
 
@@ -172,7 +174,7 @@ void VncThread::emitStarted()
  */
 char* VncThread::passwdHandler(rfbClient *client)
 {
-	VncThread* t = reinterpret_cast<VncThread*>(rfbClientGetClientData(client, nullptr));
+	auto* t = reinterpret_cast<VncThread*>(rfbClientGetClientData(client, nullptr));
 	return strdup(t->_passwd.toUtf8());
 }
 
@@ -185,7 +187,7 @@ char* VncThread::passwdHandler(rfbClient *client)
  */
 rfbBool VncThread::frameBufferHandler(rfbClient *client)
 {
-	VncThread *t = reinterpret_cast<VncThread*>(rfbClientGetClientData(client, nullptr));
+	auto *t = reinterpret_cast<VncThread*>(rfbClientGetClientData(client, nullptr));
 	const int width = client->width, height = client->height, depth = 32;
 	const int size = width * height * (depth / 8);
 	qDebug("[%s] Remote desktop: %ix%ix%i", t->metaObject()->className(), width, height, depth);
@@ -196,8 +198,8 @@ rfbBool VncThread::frameBufferHandler(rfbClient *client)
 	}
 
 	t->_img = QSharedPointer<QImage>(new QImage(width, height, QImage::Format_RGB32));
-	if (size > t->_img->byteCount()) {
-		qDebug() << "Fatal: Created image too small:" << t->_img->byteCount() << "<" << size;
+	if (size > t->_img->sizeInBytes()) {
+		qDebug() << "Fatal: Created image too small:" << t->_img->sizeInBytes() << "<" << size;
 		::exit(1);
 	}
 	client->frameBuffer = t->_img->bits();
@@ -260,6 +262,6 @@ rfbBool VncThread::frameBufferHandler(rfbClient *client)
  */
 void VncThread::updateImage(rfbClient* client, int x, int y, int w, int h)
 {
-	VncThread* t = (VncThread*)rfbClientGetClientData(client, 0);
+	auto* t = (VncThread*)rfbClientGetClientData(client, 0);
 	t->processImageUpdate(x, y, w, h);
 }
diff --git a/src/client/vnc/vncthread.h b/src/client/vnc/vncthread.h
index 16491fe..f7a020b 100644
--- a/src/client/vnc/vncthread.h
+++ b/src/client/vnc/vncthread.h
@@ -38,7 +38,7 @@ class VncThread : public QThread
 	Q_OBJECT
 
 private:
-	rfbClient *_client;
+	rfbClient *_client{};
 
 	QString _host;
 	int _port;
@@ -47,7 +47,7 @@ private:
 
 	QSharedPointer<QImage> _img;
 
-	volatile bool _connected;
+	volatile bool _connected{};
 	volatile bool _run;
 	bool _started;
 
@@ -63,13 +63,13 @@ private:
 
 public:
 	VncThread(QString host, int port, QString passwd, int quality);
-	~VncThread();
+	~VncThread() override;
 
-	const QString getDesktopName() const;
-	bool isConnected() { return _connected; }
+	QString getDesktopName() const;
+	bool isConnected() const { return _connected; }
 	void stop() { _run = false; }
 	const QSharedPointer<QImage>& getFrameBuffer() { return _img; }
-	void run();
+	void run() override;
 
 	int const static HIGH = 0;
 	int const static MEDIUM = 1;
diff --git a/src/client/vnc/vncwindow.cpp b/src/client/vnc/vncwindow.cpp
index f7b6a3e..0947112 100644
--- a/src/client/vnc/vncwindow.cpp
+++ b/src/client/vnc/vncwindow.cpp
@@ -19,7 +19,11 @@
 #include "vncthread.h"
 #include "../clientapp/clientapp.h"
 
+#include <QGuiApplication>
 #include <QTimer>
+#include <QPainter>
+#include <QScreen>
+#include <QKeyEvent>
 
 /**
  * Calc greatest common divisor.
@@ -39,15 +43,12 @@ VncWindow::VncWindow(QWidget *parent) :
 	QWidget(parent), _srcStepX(1), _srcStepY(1), _dstStepX(1), _dstStepY(1),
 	_vncWorker(nullptr), _viewOnly(true), _multiScreen(false), _clientId(0), _redrawTimer(0), _tcpTimeoutTimer(0)
 {
-	QTimer *upper = new QTimer(this);
-	connect(upper, SIGNAL(timeout()), this, SLOT(timer_moveToTop()));
+	auto *upper = new QTimer(this);
+	connect(upper, &QTimer::timeout, this, &VncWindow::timer_moveToTop);
 	upper->start(1111);
 }
 
-VncWindow::~VncWindow()
-{
-	//
-}
+VncWindow::~VncWindow() = default;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Private
@@ -64,10 +65,9 @@ void VncWindow::terminateVncThread()
 	if (_vncWorker == nullptr)
 		return;
 
-	disconnect(_vncWorker, SIGNAL(projectionStopped()), this, SLOT(onProjectionStopped()));
-	disconnect(_vncWorker, SIGNAL(projectionStarted()), this, SLOT(onProjectionStarted()));
-	disconnect(_vncWorker, SIGNAL(imageUpdated(const int, const int, const int, const int)), this,
-			SLOT(onUpdateImage(const int, const int, const int, const int)));
+	disconnect(_vncWorker, &VncThread::projectionStopped, this, &VncWindow::onProjectionStopped);
+	disconnect(_vncWorker, &VncThread::projectionStarted, this, &VncWindow::onProjectionStarted);
+	disconnect(_vncWorker, &VncThread::imageUpdated, this, &VncWindow::onUpdateImage);
 	_vncWorker->stop();
 	_vncWorker = nullptr;
 	if (_redrawTimer != 0) {
@@ -188,12 +188,10 @@ void VncWindow::open(const QString& host, int port, const QString& passwd, bool
 	this->terminateVncThread();
 	_clientId = clientId;
 	_vncWorker = new VncThread(host, port, passwd, 1);
-	connect(_vncWorker, SIGNAL(projectionStopped()), this, SLOT(onProjectionStopped()), Qt::QueuedConnection);
-	connect(_vncWorker, SIGNAL(projectionStarted()), this, SLOT(onProjectionStarted()), Qt::QueuedConnection);
-	connect(_vncWorker, SIGNAL(imageUpdated(const int, const int, const int, const int)), this,
-	        SLOT(onUpdateImage(const int, const int, const int, const int)),
-	        Qt::QueuedConnection);
-	connect(_vncWorker, SIGNAL(finished()), this, SLOT(deleteVncThread()), Qt::QueuedConnection);
+	connect(_vncWorker, &VncThread::projectionStopped, this, &VncWindow::onProjectionStopped, Qt::QueuedConnection);
+	connect(_vncWorker, &VncThread::projectionStarted, this, &VncWindow::onProjectionStarted, Qt::QueuedConnection);
+	connect(_vncWorker, &VncThread::imageUpdated, this, &VncWindow::onUpdateImage, Qt::QueuedConnection);
+	connect(_vncWorker, &VncThread::finished, this, &VncWindow::deleteVncThread, Qt::QueuedConnection);
 
 	setWindowTitle(caption);
 
@@ -201,22 +199,18 @@ void VncWindow::open(const QString& host, int port, const QString& passwd, bool
 
 	_remoteThumb.loadFromData(rawThumb);
 
-	QSize size;
 	if (fullscreen) {
 		setWindowFlags(Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint | Qt::Tool); // | Qt::X11BypassWindowManagerHint); <- better, but window won't get any keyboard input
 		// Show projection on rightmost screen
-		QDesktopWidget *desktop = QApplication::desktop();
-		int ns = desktop->numScreens();
 		QRect best;
-		for (int i = 0; i < ns; ++i) {
-			QRect r = desktop->screenGeometry(i);
+		for (auto *screen : QGuiApplication::screens()) {
+			QRect r = screen->geometry();
 			if (best.isNull() || r.left() > best.left()) {
 				best = r;
 			}
 		}
-		_multiScreen = ns > 1;
-		qDebug() << "Spawning at" << best;
-		size = best.size();
+		_multiScreen = QGuiApplication::screens().size() > 1;
+		qDebug() << "Spawning VNC viewer at" << best;
 		show();
 		setGeometry(best);
 		raise();
@@ -226,8 +220,7 @@ void VncWindow::open(const QString& host, int port, const QString& passwd, bool
 		move(best.topLeft());
 	} else {
 		setWindowFlags(Qt::Tool | Qt::WindowMaximizeButtonHint);
-		size = QSize(800, 600);
-		resize(size);
+		resize(800, 600);
 		showNormal();
 	}
 
diff --git a/src/client/vnc/vncwindow.h b/src/client/vnc/vncwindow.h
index 7124ddc..0e50ff9 100644
--- a/src/client/vnc/vncwindow.h
+++ b/src/client/vnc/vncwindow.h
@@ -14,12 +14,13 @@
 #ifndef CLIENTVNCVIEWER_H_
 #define CLIENTVNCVIEWER_H_
 
-#include <QtWidgets>
 #include <QSharedPointer>
-#include <QImage>
+#include <QWidget>
+#include <QPixmap>
 
 class VncThread;
 class QPainter;
+class QImage;
 
 class VncWindow : public QWidget
 {
@@ -36,8 +37,8 @@ protected slots:
 	void timer_moveToTop();
 	void deleteVncThread();
 
+public slots:
 	void open(const QString& host, int port, const QString& passwd, bool ro, bool fullscreen, const QString& caption, const int clientId, const QByteArray& rawThumb);
-//	bool close();
 
 signals:
 	void running(const bool isRunning, const int clientId);
diff --git a/src/server/clicklabel/clicklabel.h b/src/server/clicklabel/clicklabel.h
index 4c5a898..cea024d 100644
--- a/src/server/clicklabel/clicklabel.h
+++ b/src/server/clicklabel/clicklabel.h
@@ -1,7 +1,6 @@
-#ifndef _CLICKLABEL_H_
-#define _CLICKLABEL_H_
+#ifndef PVS_CLICKLABEL_H_
+#define PVS_CLICKLABEL_H_
 
-#include <QtWidgets>
 #include <QLabel>
 
 /**
@@ -12,10 +11,10 @@ class ClickLabel : public QLabel
 	Q_OBJECT
 
 public:
-	ClickLabel(QWidget *parent);
+	explicit ClickLabel(QWidget *parent);
 
 protected:
-	void mouseReleaseEvent(QMouseEvent* e);
+	void mouseReleaseEvent(QMouseEvent* e) override;
 
 
 signals:
diff --git a/src/server/connectionframe/connectionframe.cpp b/src/server/connectionframe/connectionframe.cpp
index c2bba70..c6c20b8 100644
--- a/src/server/connectionframe/connectionframe.cpp
+++ b/src/server/connectionframe/connectionframe.cpp
@@ -16,46 +16,51 @@
 
 #include "connectionframe.h"
 #include "../mainwindow/mainwindow.h"
+#include "../../shared/util.h"
 #include "../net/client.h"
-#include <QImage>
-#include <cassert>
-#include <cmath>
 
-static QString style_student(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
-	QGroupBox { background-color: #AAA; margin: 2px; border-radius: 4px}"
+#include <QImage>
+#include <QResizeEvent>
+#include <QBoxLayout>
+#include <QLabel>
+#include <QApplication>
+#include <QPainter>
+
+static const QString style_student(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;}"
+	" QGroupBox { background-color: #AAA; margin: 2px; border-radius: 4px}"
 );
-static QString style_tutor(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
-	QGroupBox { background-color: #70C670; margin: 2px; border-radius: 4px}"
+static const QString style_tutor(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;}"
+	" QGroupBox { background-color: #70C670; margin: 2px; border-radius: 4px}"
 );
-static QString style_attention(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
-	QGroupBox { background-color: #C88; margin: 2px; border-radius: 4px}"
+static const QString style_attention(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;}"
+	" QGroupBox { background-color: #C88; margin: 2px; border-radius: 4px}"
 );
-static QString style_selectedStudent(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black; } \
-		QGroupBox { background-color: #ccebff; margin: 0px; border-radius: 4px; border: 4px solid #6C8CF0;}"
+static const QString style_selectedStudent(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black; }"
+	" QGroupBox { background-color: #ccebff; margin: 0px; border-radius: 4px; border: 4px solid #6C8CF0;}"
 );
-static QString style_selectedTutor(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
-		QGroupBox { background-color: #9f9; margin: 0px;  border-radius: 4px; border: 4px solid #6C8CF0;}"
+static const QString style_selectedTutor(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;}"
+	" QGroupBox { background-color: #9f9; margin: 0px;  border-radius: 4px; border: 4px solid #6C8CF0;}"
 );
-static QString style_selectedAttention(
-    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
-		QGroupBox { background-color: #E99; margin: 0px;  border-radius: 4px; border: 4px solid #6C8CF0;}"
+static const QString style_selectedAttention(
+    "QLabel{ background-color: #FFF; border-radius: 2px; color: black;}"
+	" QGroupBox { background-color: #E99; margin: 0px;  border-radius: 4px; border: 4px solid #6C8CF0;}"
 );
-static QString style_exam (
-    "QLabel{ background-color: #919191; color: black; } \
-		QGroupBox { background-color: #d35400; margin: 1px; border-radius: 4px}"
+static const QString style_exam (
+    "QLabel{ background-color: #919191; color: black; }"
+	" QGroupBox { background-color: #d35400; margin: 1px; border-radius: 4px}"
 );
-static QString style_exam_selected (
-    "QLabel{ background-color: #919191; color: black; } \
-		QGroupBox { background-color: #cc743a; margin: 1px; border-radius: 4px}"
+static const QString style_exam_selected (
+    "QLabel{ background-color: #919191; color: black; }"
+	" QGroupBox { background-color: #cc743a; margin: 1px; border-radius: 4px}"
 );
-static QString style_disconnected(
-    "QLabel{ background-color: #919191; border-radius: 2px; color: black; } \
-		QGroupBox { background-color: #7F7F7F; margin: 1px; border-radius: 4px}"
+static const QString style_disconnected(
+    "QLabel{ background-color: #919191; border-radius: 2px; color: black; }"
+	" QGroupBox { background-color: #7F7F7F; margin: 1px; border-radius: 4px}"
 );
 
 static QIcon *term = nullptr, *cam = nullptr, *eye = nullptr, *lock = nullptr;
@@ -70,9 +75,10 @@ bool ConnectionFrame::paintDisabled = false;
  * @param width
  * @param height
  */
-ConnectionFrame::ConnectionFrame(MainWindow* main, QWidget *parent, bool fromRoomplan) :
-	QGroupBox(parent), _client(nullptr), _timerId(0), _timerCounter(0), _isSelected(false), _isTutor(false),
-	_isFromRoomplan(fromRoomplan), _mainWindow(main)
+ConnectionFrame::ConnectionFrame(MainWindow* main, QWidget *parent, bool fromRoomplan)
+		: QGroupBox(parent)
+		, _isFromRoomplan(fromRoomplan)
+		, _mainWindow(main)
 {
 
 	//defines the ui-stuff
@@ -158,7 +164,7 @@ void ConnectionFrame::updateGeometry()
  */
 QLabel* ConnectionFrame::addIcon(const QIcon* icon)
 {
-	QLabel *label = new QLabel(this);
+	auto *label = new QLabel(this);
 	label->setPixmap(icon->pixmap(24, 24, QIcon::Normal, QIcon::On));
 	label->setAttribute(Qt::WA_TranslucentBackground);
 	label->hide();
@@ -174,17 +180,17 @@ QLabel* ConnectionFrame::addIcon(const QIcon* icon)
 void ConnectionFrame::assignClient(Client* client)
 {
 	assert(_client == nullptr);
-	connect( client, SIGNAL(disconnected()), this, SLOT(onClientDisconnected()) );
-	connect( client, SIGNAL(thumbUpdated(Client*, const QImage&)), this, SLOT(onThumbUpdated(Client*, const QImage&)) );
-	connect( client, SIGNAL(vncServerStateChange(Client*)), this, SLOT(updateAppearance()));
-	connect( client, SIGNAL(vncClientStateChange(Client*)), this, SLOT(updateAppearance()));
-	connect( client, SIGNAL(stateChanged()), this, SLOT(updateAppearance()));
 	_client = client;
+	connect(_client, &Client::disconnected, this, &ConnectionFrame::onClientDisconnected );
+	connect(_client, &Client::thumbUpdated, this, &ConnectionFrame::onThumbUpdated );
+	connect(_client, &Client::vncServerStateChange, this, &ConnectionFrame::updateAppearance);
+	connect(_client, &Client::vncClientStateChange, this, &ConnectionFrame::updateAppearance);
+	connect(_client, &Client::stateChanged, this, &ConnectionFrame::updateAppearance);
 	_computerId = client->ip();
 	updateLabels();
 	showDefaultThumb();
 	if (_timerId == 0)
-		_timerId = startTimer(1000 + qrand() % 150);
+		_timerId = startTimer(slxrand() % 150 + 1000);
 	this->updateAppearance();
 	_client->setTutor(_isTutor);
 }
@@ -382,8 +388,8 @@ void ConnectionFrame::updateAppearance()
 		} else {
 			this->setStyleSheet(style_disconnected);
 		}
-		for (QList<QLabel*>::iterator it(_icons.begin()); it != _icons.end(); ++it) {
-			(**it).hide();
+		for (auto *_icon : _icons) {
+			_icon->hide();
 		}
 		return;
 	}
@@ -448,3 +454,8 @@ void ConnectionFrame::onThumbUpdated(Client* client, const QImage& thumb)
 	this->update();
 }
 
+void ConnectionFrame::resizeEvent(QResizeEvent *event) {
+	calcDesiredThumbSize(event->size());
+	QGroupBox::resizeEvent(event);
+}
+
diff --git a/src/server/connectionframe/connectionframe.h b/src/server/connectionframe/connectionframe.h
index 1d004e6..cfebe85 100644
--- a/src/server/connectionframe/connectionframe.h
+++ b/src/server/connectionframe/connectionframe.h
@@ -1,9 +1,14 @@
-#ifndef _CONNECTIONFRAME_H_
-#define _CONNECTIONFRAME_H_
-#include <QtWidgets>
-#include "../net/client.h"
+#ifndef PVS_CONNECTIONFRAME_H_
+#define PVS_CONNECTIONFRAME_H_
+
+#include <QGroupBox>
+#include <utility>
+
+class QBoxLayout;
+class QLabel;
 
 class MainWindow;
+class Client;
 
 /**
  * Class for representing the clients of current session, with a specific frame
@@ -34,11 +39,11 @@ private:
 	QPoint _gridPosition;
 	QSize _desiredThumbSize;
 
-	Client *_client;
+	Client *_client{};
 
-	int _timerId, _timerCounter;
-	bool _isSelected;
-	bool _isTutor;
+	int _timerId{}, _timerCounter{};
+	bool _isSelected{};
+	bool _isTutor{};
 	bool _isFromRoomplan;
 
 	void showDefaultThumb();
@@ -52,35 +57,39 @@ public:
 	static bool paintDisabled;
 
 	ConnectionFrame(MainWindow* main, QWidget* parent, bool fromRoomplan = false);
-	virtual ~ConnectionFrame();
+	~ConnectionFrame() override;
 
-	const inline QPoint getGridPosition() const { return _gridPosition; }
+	const QPoint& getGridPosition() const { return _gridPosition; }
 	void setGridPosition(int x, int y);
 	void setGridPosition(const QPoint& pos);
 	void updateGeometry();
 
 	void assignClient(Client *client);
 	void setSelection(bool selected);
-	inline bool isSelected() { return _isSelected; }
+	bool isSelected() const { return _isSelected; }
 
 	const QString& computerId() const { return _computerId; }
-	void setComputerId(QString computerId) { if (_client != nullptr) return; _computerId = computerId; updateLabels(); }
+	void setComputerId(QString computerId) {
+		if (_client != nullptr)
+			return;
+		_computerId = std::move(computerId); updateLabels();
+	}
 	Client* client() const { return _client; }
 
-	inline bool isTutor() { return _isTutor; }
-	inline bool isFromRoomplan() { return _isFromRoomplan; }
+	bool isTutor() const { return _isTutor; }
+	bool isFromRoomplan() const { return _isFromRoomplan; }
 	void setTutor(bool b);
 
 protected:
-	void resizeEvent(QResizeEvent* event) { calcDesiredThumbSize(event->size()); }
-	void mouseDoubleClickEvent(QMouseEvent* event);
-	void mouseReleaseEvent(QMouseEvent* e);
-	void enterEvent(QEvent* event);
-	void leaveEvent(QEvent* event);
-	void mousePressEvent(QMouseEvent* event);
-	void mouseMoveEvent(QMouseEvent* event);
-	void paintEvent(QPaintEvent *event);
-	void timerEvent(QTimerEvent* event);
+	void resizeEvent(QResizeEvent* event) override;
+	void mouseDoubleClickEvent(QMouseEvent* event) override;
+	void mouseReleaseEvent(QMouseEvent* e) override;
+	void enterEvent(QEvent* event) override;
+	void leaveEvent(QEvent* event) override;
+	void mousePressEvent(QMouseEvent* event) override;
+	void mouseMoveEvent(QMouseEvent* event) override;
+	void paintEvent(QPaintEvent *event) override;
+	void timerEvent(QTimerEvent* event) override;
 
 signals:
 	void frameMoving(ConnectionFrame* frame);
diff --git a/src/server/helpwindow/helpwindow.cpp b/src/server/helpwindow/helpwindow.cpp
index 152cf0d..f6f1f10 100644
--- a/src/server/helpwindow/helpwindow.cpp
+++ b/src/server/helpwindow/helpwindow.cpp
@@ -22,7 +22,7 @@ HelpWindow::HelpWindow(const QList<QAction*> &actions, QWidget *parent) :
 			break;
 		}
 	}
-	QGridLayout *layout = new QGridLayout(this);
+	auto *layout = new QGridLayout(this);
 	layout->setSpacing(2);
 	QSizePolicy sizePol(QSizePolicy::Minimum, QSizePolicy::Preferred);
 	QList<QLabel*> wrapLabels;
@@ -31,24 +31,24 @@ HelpWindow::HelpWindow(const QList<QAction*> &actions, QWidget *parent) :
 	for (QAction *action : actions) {
 		if (action->icon().isNull() || action->text().isEmpty())
 			continue;
-		QLabel *icon = new QLabel(this);
+		auto *icon = new QLabel(this);
 		icon->setPixmap(action->icon().pixmap(iconSize, iconSize, QIcon::Normal, QIcon::Off));
 		icon->setMinimumSize(iconSize + 5, iconSize + 2);
 		layout->addWidget(icon, row, 0, 3, 1, Qt::AlignTop | Qt::AlignLeft);
-		QLabel *headline = new QLabel(action->toolTip(), this);
+		auto *headline = new QLabel(action->toolTip(), this);
 		QFont boldFont = headline->font();
 		boldFont.setBold(true);
 		headline->setFont(boldFont);
 		headline->setAlignment(Qt::AlignTop | Qt::AlignLeft);
 		layout->addWidget(headline, row, 1, Qt::AlignTop);
-		QLabel *description = new QLabel(action->text(), this);
+		auto *description = new QLabel(action->text(), this);
 		description->setWordWrap(true);
 		description->setAlignment(Qt::AlignTop | Qt::AlignLeft);
 		description->setSizePolicy(sizePol);
 		wrapLabels.append(description);
 		layout->addWidget(description, row + 1, 1, Qt::AlignTop);
 		layout->setRowStretch(row + 2, 1);
-		QFrame *line = new QFrame();
+		auto *line = new QFrame();
 		line->setFrameShape(QFrame::HLine);
 		line->setFrameShadow(QFrame::Sunken);
 		layout->addWidget(line, row + 3, 0, 1, 2);
@@ -57,12 +57,12 @@ HelpWindow::HelpWindow(const QList<QAction*> &actions, QWidget *parent) :
 	layout->setColumnStretch(1, 1);
 	// Add close button
 	layout->setRowStretch(row++, 1000);
-	QPushButton *close = new QPushButton(tr("Close"), this);
+	auto *close = new QPushButton(tr("Close"), this);
 	QFont bigFont = close->font();
 	bigFont.setPointSize(20);
 	close->setFont(bigFont);
 	close->setDefault(true);
-	connect(close, SIGNAL(clicked()), this, SLOT(hide()));
+	connect(close, &QPushButton::clicked, this, &HelpWindow::hide);
 	layout->addWidget(close, row++, 0, 1, 2);
 	this->setFixedWidth(600);
 	this->setSizePolicy(sizePol);
diff --git a/src/server/main.cpp b/src/server/main.cpp
index f804c1a..d975f80 100644
--- a/src/server/main.cpp
+++ b/src/server/main.cpp
@@ -1,27 +1,25 @@
-#include <iostream>
-#include <stdlib.h>
 #include "mainwindow/mainwindow.h"
 #include "serverapp/serverapp.h"
 
-using std::cout;
-using std::endl;
+#include <QDebug>
 
 void usage()
 {
-	cout << "USAGE pvsmgr [OPTIONS]" << endl;
-	cout << "OPTIONS: " << endl;
-	cout << "--manager-only" << endl;
-	cout << "    pvsmgr terminates if this computer is not a manager of a room" << endl;
-	cout << "--config=INIFILE" << endl;
-	cout << "    read configuration from INIFILE instead of default path (/opt/openslx/pvs2/pvs2.ini) " << endl;
-	cout << "--usage" << endl;
-	cout << "    shows this message" << endl;
+	puts(
+		"USAGE pvsmgr [OPTIONS]\n"
+		"OPTIONS: \n"
+		"--manager-only\n"
+		"    pvsmgr terminates if this computer is not a manager of a room\n"
+		"--config=INIFILE\n"
+		"    read configuration from INIFILE instead of default path (/opt/openslx/pvs2/pvs2.ini) \n"
+		"--usage\n"
+		"    shows this message\n"
+	);
 }
 
 
 int main(int argc, char** argv)
 {
-	qsrand(uint(QDateTime::currentMSecsSinceEpoch()));
 	ServerApp app(argc, argv);
 
 	for (QString a : app.arguments()) {
diff --git a/src/server/mainwindow/mainwindow.cpp b/src/server/mainwindow/mainwindow.cpp
index b63545f..e8247d0 100644
--- a/src/server/mainwindow/mainwindow.cpp
+++ b/src/server/mainwindow/mainwindow.cpp
@@ -16,11 +16,13 @@
 // Self
 #include "mainwindow.h"
 // QT stuff
-#include <QtWidgets>
-#include <QFileDialog>
 #include <QSvgRenderer>
 #include <QPainter>
 #include <QImage>
+#include <QMessageBox>
+#include <QCloseEvent>
+#include <QDialogButtonBox>
+#include <QScreen>
 // Other custom UI elements
 #include "../serverapp/serverapp.h"
 #include "../clicklabel/clicklabel.h"
@@ -32,16 +34,12 @@
 #include "../net/listenserver.h"
 #include "../net/client.h"
 #include "../net/discoverylistener.h"
-#include "../net/filedownloader.h"
 // Others
 #include "../../shared/settings.h"
 #include "../util/platform/screensaver.h"
 // Auto-generated ui class
 #include "ui_mainwindow.h"
 
-#include <iostream>
-#include <vector>
-
 #define sStrTutorNdef MainWindow::tr("No tutor defined.")
 #define sStrTutorOffline MainWindow::tr("Tutor is offline.")
 #define sStrSourceNdef MainWindow::tr("Please select a projection source.")
@@ -49,33 +47,24 @@
 #define sStrDestNdef MainWindow::tr("Please select a projection destination.")
 #define sStrDestOffline MainWindow::tr("The projection destination is offline.")
 #define sStrSourceDestSame MainWindow::tr("Selected projection target is tutor.")
-#define sStrClientOnline MainWindow::tr("Selected client is currently online.")
 #define sStrNoDestAv MainWindow::tr("No projection destination available.")
 
-using std::vector;
-using std::cout;
-using std::endl;
-
 /**
  * Initialize MainWindow and ListenServer.
  * @param ipListUrl
  * @param parent
  */
-MainWindow::MainWindow(QWidget* parent) :
-	QMainWindow(parent), ui(new Ui::MainWindow), _tbIconSize(24), _tbArea(Qt::LeftToolBarArea),
-	_lastClientCount(0)
+MainWindow::MainWindow(QWidget* parent)
+		: QMainWindow(parent)
+		, ui(new Ui::MainWindow)
+		, _mode(Mode::Multicast)
 {
 	qDebug() << "MainWindow(parent)";
-	_mode = Mode::Multicast;
-	_streamingSource = 0;
 
 	/* default value, these will be updated a room is loaded */
 	_tilesX = 10;
 	_tilesY = 10;
 
-	_virtCols = 0;
-	_virtRows = 0;
-
 	_sessionNameWindow = new SessionNameWindow(this);
 	_reloadWindow = new ReloadRoomWindow(this);
 	_reloadWindow->setWindowTitle(tr("Reload Room"));
@@ -113,26 +102,26 @@ MainWindow::MainWindow(QWidget* parent) :
 	serverApp->setExam(false);
 
 	// Close button in tool bar
-	connect(ui->action_Exit, SIGNAL(triggered()), this, SLOT(onButtonExit()));
-	connect(ui->action_TutorToAll, SIGNAL(triggered()), this, SLOT(onButtonTutorToAll()));
-	connect(ui->action_StudentToTutor, SIGNAL(triggered()), this, SLOT(onButtonStudentToTutor()));
-	connect(ui->action_StudentToTutorExclusive, SIGNAL(triggered()), this, SLOT(onButtonStudentToTutorExclusive()));
-	connect(ui->action_TutorToStudent, SIGNAL(triggered()), this, SLOT(onButtonTutorToStudent()));
-	connect(ui->action_StopProjection, SIGNAL(triggered()), this, SLOT(onButtonStopProjection()));
-	connect(ui->action_SetAsTutor, SIGNAL(triggered()), this, SLOT(onButtonSetAsTutor()));
-	connect(ui->action_SetAsTutor, SIGNAL(triggered()), this, SLOT(onButtonStopProjection()));
-	connect(ui->action_Lock, SIGNAL(toggled(bool)), this, SLOT(onButtonLock(bool)));
-	connect(ui->action_LockSingle, SIGNAL(triggered()), this, SLOT(onButtonLockSingle()));
-	connect(ui->action_Help, SIGNAL(triggered()), this, SLOT(onButtonHelp()));
-	connect(ui->actionReload_Room_Configuration, SIGNAL(triggered()), this, SLOT(onButtonReloadRoomConfig()));
-	connect(ui->action_DeleteClient, SIGNAL(triggered()), this, SLOT(onDeleteClient()));
+	connect(ui->action_Exit, &QAction::triggered, this, &MainWindow::onButtonExit);
+	connect(ui->action_TutorToAll, &QAction::triggered, this, &MainWindow::onButtonTutorToAll);
+	connect(ui->action_StudentToTutor, &QAction::triggered, this, &MainWindow::onButtonStudentToTutor);
+	connect(ui->action_StudentToTutorExclusive, &QAction::triggered, this, &MainWindow::onButtonStudentToTutorExclusive);
+	connect(ui->action_TutorToStudent, &QAction::triggered, this, &MainWindow::onButtonTutorToStudent);
+	connect(ui->action_StopProjection, &QAction::triggered, this, &MainWindow::onButtonStopProjection);
+	connect(ui->action_SetAsTutor, &QAction::triggered, this, &MainWindow::onButtonSetAsTutor);
+	connect(ui->action_SetAsTutor, &QAction::triggered, this, &MainWindow::onButtonStopProjection);
+	connect(ui->action_Lock, &QAction::toggled, this, &MainWindow::onButtonLock);
+	connect(ui->action_LockSingle, &QAction::triggered, this, &MainWindow::onButtonLockSingle);
+	connect(ui->action_Help, &QAction::triggered, this, &MainWindow::onButtonHelp);
+	connect(ui->actionReload_Room_Configuration, &QAction::triggered, this, &MainWindow::onButtonReloadRoomConfig);
+	connect(ui->action_DeleteClient, &QAction::triggered, this, &MainWindow::onDeleteClient);
 
 	/* Stuff for the button lock */
 	//Setup a timeout
 	_buttonLockTimer = new QTimer(this);
 	_buttonLockTimer->setSingleShot(true);
 	_buttonLockTimer->setInterval(BUTTON_BLOCK_TIME);
-	connect(_buttonLockTimer, SIGNAL(timeout()), this, SLOT(enableButtons()));
+	connect(_buttonLockTimer, &QTimer::timeout, this, &MainWindow::enableButtons);
 	// Define the locking buttons
 	_lockingButtons
 			<< ui->action_DeleteClient
@@ -146,18 +135,18 @@ MainWindow::MainWindow(QWidget* parent) :
 			<< ui->action_StopProjection;
 
 	// Clicking the session name label shows the edit field for it
-	connect(_sessionNameLabel, SIGNAL(clicked()), this, SLOT(onSessionNameClick()));
+	connect(_sessionNameLabel, &ClickLabel::clicked, this, &MainWindow::onSessionNameClick);
 	// Listen to updates to the session name through the session name window
-	connect(_sessionNameWindow, SIGNAL(updateSessionName()), this,
-	        SLOT(onSessionNameUpdate()));
+	connect(_sessionNameWindow, &SessionNameWindow::updateSessionName,
+			this, &MainWindow::onSessionNameUpdate);
 
 	setAttribute(Qt::WA_QuitOnClose);
 	setUnifiedTitleAndToolBarOnMac(true);
 	this->showMaximized(); // show the Mainwindow maximized
 
-	_listenServer = new ListenServer(CLIENT_PORT);
-	connect(_listenServer, SIGNAL(newClient(Client*)), this, SLOT(onClientConnected(Client*)));
-	_discoveryListener = new DiscoveryListener();
+	auto *ls = new ListenServer(CLIENT_PORT, this);
+	connect(ls, &ListenServer::newClient, this, &MainWindow::onClientConnected);
+	new DiscoveryListener(this);
 
 	// Finally
 	this->onSessionNameUpdate(); // Just make lable visible.
@@ -174,8 +163,8 @@ void MainWindow::clientCountChanged()
 	int clientCount = 0;
 
 
-	for (auto it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
-		Client* c = (*it)->client();
+	for (auto * frame : _clientFrames) {
+		Client* c = frame->client();
 		if (c != nullptr) {
 			bool b = c->isExamMode();
 			examClientCount += b ? 1 : 0;
@@ -240,7 +229,7 @@ static int distance(QPoint a, QPoint b)
  * @param toIgnore, ignore this connectionframe when considering free slots
  * @return the free slot
  */
-QPoint MainWindow::closestFreeSlot(const QPoint preferredPixels, const ConnectionFrame* toIgnore)
+QPoint MainWindow::closestFreeSlot(const QPoint &preferredPixels, const ConnectionFrame* toIgnore)
 {
 	const bool pickFirstOne = ( preferredPixels == QPoint(-1, -1) );
 	const QSize& clientSize = serverApp->getCurrentRoom()->clientSize;
@@ -249,11 +238,11 @@ QPoint MainWindow::closestFreeSlot(const QPoint preferredPixels, const Connectio
 	memset(grid, 0, sizeof(bool) * size_t(_tilesX * _tilesY)); /* set everything to false */
 
 	/* fill grid */
-	for (auto  it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
+	for (auto * frame : _clientFrames) {
 
-		if (*it == toIgnore) { continue; }
+		if (frame == toIgnore) { continue; }
 
-		const QPoint p = (*it)->getGridPosition();
+		const QPoint p = frame->getGridPosition();
 
 		for (int x = p.x(); x < p.x() + clientSize.width(); x++) {
 			for (int y = p.y(); y < p.y() + clientSize.height(); y++) {
@@ -322,7 +311,7 @@ void MainWindow::placeFrameInFreeSlot(ConnectionFrame* frame, QPoint preferredPi
  */
 ConnectionFrame* MainWindow::createFrame(const QString &computerId, const QPoint* gridPosition, bool fromRoomplan)
 {
-	ConnectionFrame *cf = new ConnectionFrame(this, ui->frmRoom, fromRoomplan);
+	auto *cf = new ConnectionFrame(this, ui->frmRoom, fromRoomplan);
 	if (gridPosition == nullptr) {
 		placeFrameInFreeSlot(cf);
 	} else {
@@ -331,9 +320,9 @@ ConnectionFrame* MainWindow::createFrame(const QString &computerId, const QPoint
 	cf->setComputerId(computerId);
 	_clientFrames.append(cf);
 	cf->show();
-	connect(cf, SIGNAL(frameMoved(ConnectionFrame *)), this, SLOT(onFrameDropped(ConnectionFrame *)));
-	connect(cf, SIGNAL(clicked(ConnectionFrame *)), this, SLOT(onFrameClicked(ConnectionFrame *)));
-	connect(cf, SIGNAL(frameMoving(ConnectionFrame *)), this, SLOT(onFrameMoving(ConnectionFrame *)));
+	connect(cf, &ConnectionFrame::frameMoved, this, &MainWindow::onFrameDropped);
+	connect(cf, &ConnectionFrame::clicked, this, &MainWindow::onFrameClicked);
+	connect(cf, &ConnectionFrame::frameMoving, this, &MainWindow::onFrameMoving);
 	return cf;
 }
 
@@ -364,10 +353,10 @@ void MainWindow::tellClientCurrentSituation(Client* client)
  */
 Client* MainWindow::getClientFromId(int id)
 {
-	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if ((*it)->client() != nullptr) {
-			if ((*it)->client()->id() == id)
-				return (*it)->client();
+	for (auto * frame : _clientFrames) {
+		if (frame->client() != nullptr) {
+			if (frame->client()->id() == id)
+				return frame->client();
 		}
 	}
 	return nullptr;
@@ -381,9 +370,9 @@ Client* MainWindow::getClientFromId(int id)
  */
 ConnectionFrame* MainWindow::getTutorFrame()
 {
-	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if (((*it) != nullptr) && ((*it)->isTutor()))
-			return (*it);
+	for (auto * frame : _clientFrames) {
+		if ((frame != nullptr) && (frame->isTutor()))
+			return frame;
 	}
 	return nullptr;
 }
@@ -396,9 +385,9 @@ ConnectionFrame* MainWindow::getTutorFrame()
  */
 ConnectionFrame* MainWindow::getSelectedFrame()
 {
-	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if (((*it) != nullptr) && ((*it)->isSelected()))
-			return (*it);
+	for (auto * frame : _clientFrames) {
+		if ((frame != nullptr) && (frame->isSelected()))
+			return frame;
 	}
 	return nullptr;
 }
@@ -469,8 +458,8 @@ void MainWindow::resizeEvent(QResizeEvent* /* e */ )
 	const QSize& clientSize = room->clientSize;
 
 	// Check if any frames have been moved beyond the room dimensions
-	for (auto it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
-		QPoint bounds = (*it)->getGridPosition();
+	for (auto * frame : _clientFrames) {
+		QPoint bounds = frame->getGridPosition();
 		while (bounds.x() + clientSize.width() > newGridSize.width()) {
 			newGridSize += QSize(1, 0);
 		}
@@ -498,16 +487,16 @@ void MainWindow::resizeEvent(QResizeEvent* /* e */ )
 	const int maxY = _tilesY - clientSize.height();
 
 	/* Bring back frames which are now out of the screen */
-	for (auto it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
-		const QPoint gp = (*it)->getGridPosition();
+	for (auto * frame : _clientFrames) {
+		const QPoint gp = frame->getGridPosition();
 		if ( gp.x() > maxX || gp.y() > maxY ) {
-			placeFrameInFreeSlot(*it, (*it)->pos());
+			placeFrameInFreeSlot(frame, frame->pos());
 		}
 	}
 
 	/* Resize all connection windows */
-	for (auto it = _clientFrames.begin(); it != _clientFrames.end(); ++it) {
-		(*it)->updateGeometry();
+	for (auto * frame : _clientFrames) {
+		frame->updateGeometry();
 	}
 
 	/* update background image label */
@@ -580,10 +569,10 @@ void MainWindow::reset(bool lock)
 	}
 
 	// Unlock all clients
-	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if ((*it)->client() != nullptr) {
-			(*it)->client()->lockScreen(lock);
-			(*it)->client()->removeAttention();
+	for (auto * frame : _clientFrames) {
+		if (frame->client() != nullptr) {
+			frame->client()->lockScreen(lock);
+			frame->client()->removeAttention();
 		}
 	}
 
@@ -595,6 +584,7 @@ void MainWindow::reset(bool lock)
 
 void MainWindow::onFrameMoving(ConnectionFrame* connectionFrame)
 {
+	// Get where the frame would be placed, and show a blue shadow in that spot
 	QPoint slot = closestFreeSlot(connectionFrame->pos(), connectionFrame);
 	_dropMarker->setGeometry(slot.x() * getTileWidthPx(), slot.y() * getTileHeightPx(), connectionFrame->width(), connectionFrame->height());
 	if (!_dropMarker->isVisible()) {
@@ -611,11 +601,8 @@ void MainWindow::onFrameMoving(ConnectionFrame* connectionFrame)
 void MainWindow::onFrameDropped(ConnectionFrame* connectionFrame)
 {
 	_dropMarker->hide();
-	// if (_tilesX <= 0 || _tilesY <= 0) return;
 	const QPoint preferredPixels = connectionFrame->pos();
 	placeFrameInFreeSlot(connectionFrame, preferredPixels);
-
-	//resizeEvent(nullptr);
 }
 
 /**
@@ -626,7 +613,7 @@ void MainWindow::onFrameClicked(ConnectionFrame* frame)
 {
 	_dropMarker->hide();
 	ConnectionFrame *current = getSelectedFrame();
-	// If same frame is clicked again,, do nothing
+	// If same frame is clicked again, do nothing
 	if (current == frame)
 		return;
 
@@ -710,19 +697,19 @@ void MainWindow::startVncServerIfNecessary(int from)
 
 void MainWindow::onButtonReloadRoomConfig()
 {
-	connect(_reloadWindow->buttonBox(), SIGNAL(accepted()), this, SLOT(onReloadRoomOk()));
-	connect(_reloadWindow->buttonBox(), SIGNAL(rejected()), this, SLOT(onReloadRoomCancel()));
+	connect(_reloadWindow->buttonBox(), &QDialogButtonBox::accepted, this, &MainWindow::onReloadRoomOk);
+	connect(_reloadWindow->buttonBox(), &QDialogButtonBox::rejected, this, &MainWindow::onReloadRoomCancel);
 	QList<QString> keyList = serverApp->getRooms().keys();
-	for (QList<QString>::iterator it = keyList.begin(); it != keyList.end() ; it++) {
-		_reloadWindow->addRoom(*it);
+	for (const auto & it : keyList) {
+		_reloadWindow->addRoom(it);
 	}
 	_reloadWindow->show();
 }
 
 void MainWindow::onReloadRoomCancel()
 {
-	disconnect(_reloadWindow->buttonBox(), SIGNAL(accepted()), this, SLOT(onReloadRoomOk()));
-	disconnect(_reloadWindow->buttonBox(), SIGNAL(rejected()), this, SLOT(onReloadRoomCancel()));
+	disconnect(_reloadWindow->buttonBox(), &QDialogButtonBox::accepted, this, &MainWindow::onReloadRoomOk);
+	disconnect(_reloadWindow->buttonBox(), &QDialogButtonBox::rejected, this, &MainWindow::onReloadRoomCancel);
 	_reloadWindow->clearRoomList();
 	_reloadWindow->hide();
 }
@@ -730,7 +717,7 @@ void MainWindow::onReloadRoomCancel()
 void MainWindow::reloadCurrentRoom()
 {
 	/* delete old image */
-	if (_backgroundImage != nullptr) {delete _backgroundImage; }
+	delete _backgroundImage;
 	_backgroundImage = nullptr;
 
 	const Room *room = serverApp->getCurrentRoom();
@@ -742,8 +729,8 @@ void MainWindow::reloadCurrentRoom()
 
 		/* place connection frames */
 		for (auto it = room->clientPositions.begin(); it != room->clientPositions.end(); ++it) {
-			QString computerId = it.key();
-			QPoint pos = it.value();
+			const QString& computerId = it.key();
+			const QPoint& pos = it.value();
 
 			ConnectionFrame *cf = createFrame(computerId, &pos, true);
 			onFrameDropped(cf);
@@ -764,7 +751,7 @@ void MainWindow::reloadCurrentRoom()
 			qDebug() << "set background image path: " << imgPath;
 			if (imgPath.endsWith("svg")) {
 				/* render once with maximal screen size */
-				const QSize &s  =  QApplication::desktop()->screenGeometry().size(); // ui->frmRoom->geometry().size();
+				QSize s = QGuiApplication::screenAt(geometry().center())->size();
 				QSvgRenderer renderer(imgPath);
 				_backgroundImage = new QImage(s, QImage::Format_ARGB32);
 				_backgroundImage->fill(Qt::lightGray); /* background color */
@@ -794,12 +781,12 @@ void MainWindow::onReloadRoomOk()
 				"Note that all clients will be deleted."),
 			QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);
 	if (ret == QMessageBox::Yes) {
-		disconnect(_reloadWindow->buttonBox(), SIGNAL(accepted()), this, SLOT(onReloadRoomOk()));
-		disconnect(_reloadWindow->buttonBox(), SIGNAL(rejected()), this, SLOT(onReloadRoomCancel()));
+		disconnect(_reloadWindow->buttonBox(), &QDialogButtonBox::accepted, this, &MainWindow::onReloadRoomOk);
+		disconnect(_reloadWindow->buttonBox(), &QDialogButtonBox::rejected, this, &MainWindow::onReloadRoomCancel);
 		// Delete all clients.
-		for (QList<ConnectionFrame*>::iterator it = _clientFrames.begin(); it != _clientFrames.end(); it++) {
-			(*it)->hide();
-			(*it)->deleteLater();
+		for (auto * frame : _clientFrames) {
+			frame->hide();
+			frame->deleteLater();
 		}
 		_clientFrames.clear();
 
@@ -864,9 +851,9 @@ void MainWindow::onButtonTutorToAll()
 		}
 
 		// Set all clients as watchers of tutor. Except for the tutors desired source, which hase to be none
-		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			if ((*it)->client() != nullptr)
-				(*it)->client()->setDesiredProjectionSource((*it)->client() == getTutorFrame()->client() ? NO_SOURCE : getTutorFrame()->client()->id());
+		for (auto * frame : _clientFrames)
+			if (frame->client() != nullptr)
+				frame->client()->setDesiredProjectionSource(frame->client() == getTutorFrame()->client() ? NO_SOURCE : getTutorFrame()->client()->id());
 
 		disableButtons();
 		_mode = Mode::Broadcast;
@@ -913,7 +900,7 @@ void MainWindow::onButtonTutorToStudent()
 
 		disableButtons();
         int numClients = 0;
-        for (auto c : _clientFrames) {
+        for (auto * c : _clientFrames) {
             if (c->client() != nullptr && c->client()->desiredProjectionSource() == sourceClient->id()) {
                 numClients++;
             }
@@ -1035,10 +1022,10 @@ void MainWindow::onButtonLockSingle()
 		client->lockScreen(newState);
 		if (!newState) {
 			// If no more clients are locked, reset button
-			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-				if ((*it)->client() == nullptr)
+			for (auto * frame : _clientFrames) {
+				if (frame->client() == nullptr)
 					continue;
-				if ((*it)->client()->isLocked())
+				if (frame->client()->isLocked())
 					return;
 			}
 			ui->action_Lock->setChecked(false);
@@ -1089,8 +1076,8 @@ void MainWindow::onButtonSetAsTutor()
  */
 void MainWindow::onClientConnected(Client* client)
 {
-	connect(client, SIGNAL(authenticating(Client*, ClientLogin*)), this, SLOT(onClientAuthenticating(Client*, ClientLogin*)));
-	connect(client, SIGNAL(authenticated(Client*)), this, SLOT(onClientAuthenticated(Client*)));
+	connect(client, &Client::authenticating, this, &MainWindow::onClientAuthenticating);
+	connect(client, &Client::authenticated, this, &MainWindow::onClientAuthenticated);
 }
 
 /**
@@ -1105,7 +1092,7 @@ void MainWindow::onClientConnected(Client* client)
  */
 void MainWindow::onClientAuthenticating(Client* client, ClientLogin* request)
 {
-	disconnect(client, SIGNAL(authenticating(Client*, ClientLogin*)), this, SLOT(onClientAuthenticating(Client*, ClientLogin*)));
+	disconnect(client, &Client::authenticating, this, &MainWindow::onClientAuthenticating);
 	/* copy examMode */
 	client->setExamMode(request->examMode);
 
@@ -1116,8 +1103,8 @@ void MainWindow::onClientAuthenticating(Client* client, ClientLogin* request)
 	int addnum = 1;
 	do {
 		inuse = false;
-		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-			Client *c = (**it).client();
+		for (auto * frame : _clientFrames) {
+			Client *c = frame->client();
 			if (c == nullptr)
 				continue;
 			if (!c->isAuthed())
@@ -1133,10 +1120,11 @@ void MainWindow::onClientAuthenticating(Client* client, ClientLogin* request)
 			}
 		}
 	} while (inuse && addnum < 100);
-	if (inuse)
+	if (inuse) {
 		request->accept = false;
-	else
+	} else {
 		request->name = check;
+	}
 }
 
 /**
@@ -1151,14 +1139,14 @@ void MainWindow::onClientAuthenticating(Client* client, ClientLogin* request)
  */
 void MainWindow::onClientAuthenticated(Client* client)
 {
-	disconnect(client, SIGNAL(authenticated(Client*)), this, SLOT(onClientAuthenticated(Client*)));
-	connect(client, SIGNAL(vncServerStateChange(Client*)), this, SLOT(onVncServerStateChange(Client*)));
-	connect(client, SIGNAL(vncClientStateChange(Client*)), this, SLOT(onVncClientStateChange(Client*)));
+	disconnect(client, &Client::authenticated, this, &MainWindow::onClientAuthenticated);
+	connect(client, &Client::vncServerStateChange, this, &MainWindow::onVncServerStateChange);
+	connect(client, &Client::vncClientStateChange, this, &MainWindow::onVncClientStateChange);
 	ConnectionFrame *existing = nullptr;
 	ConnectionFrame *cf = nullptr;
-	for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-		if ((*it)->computerId() == client->ip()) {
-			existing = *it;
+	for (auto * frame : _clientFrames) {
+		if (frame->computerId() == client->ip()) {
+			existing = frame;
 		}
 	}
 
@@ -1170,7 +1158,7 @@ void MainWindow::onClientAuthenticated(Client* client)
 	}
 
 	cf->assignClient(client);
-	connect(client, SIGNAL(disconnected()), this, SLOT(clientCountChanged()));
+	connect(client, &Client::disconnected, this, &MainWindow::clientCountChanged);
 	tellClientCurrentSituation(client);
 	clientCountChanged();
 }
@@ -1203,13 +1191,13 @@ void MainWindow::onVncServerStateChange(Client* client)
 		client->lockScreen(false);
 	} else {
 		// VNC server stopped on some client or failed to start - reset local pending projection information
-		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it) {
-			if ((*it)->client() != nullptr) {
-				if ((*it)->client()->desiredProjectionSource() == client->id()) {
-					(*it)->client()->setDesiredProjectionSource(NO_SOURCE);
-					(*it)->client()->stopVncClient();
+		for (auto * frame : _clientFrames) {
+			if (frame->client() != nullptr) {
+				if (frame->client()->desiredProjectionSource() == client->id()) {
+					frame->client()->setDesiredProjectionSource(NO_SOURCE);
+					frame->client()->stopVncClient();
 					if (_mode == Mode::LockedUnicast)
-						(*it)->client()->lockScreen(true);
+						frame->client()->lockScreen(true);
 				}
 			}
 		}
@@ -1250,14 +1238,14 @@ void MainWindow::onVncClientStateChange(Client* client)
 			 * the new connect.
 			 */
 			bool serverHasWatchers = false;
-			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-				if ((*it)->client() != nullptr)
-					if ((*it)->client()->desiredProjectionSource() == client->projectionSource()) {
+			for (auto * frame : _clientFrames)
+				if (frame->client() != nullptr)
+					if (frame->client()->desiredProjectionSource() == client->projectionSource()) {
 						serverHasWatchers = true;
 						break;
 					}
 
-			if ( !serverHasWatchers ) {
+			if (!serverHasWatchers) {
 				Client* c = getClientFromId(client->projectionSource());
 				if (c != nullptr)
 					c->stopVncServer();
diff --git a/src/server/mainwindow/mainwindow.h b/src/server/mainwindow/mainwindow.h
index 86499af..d4967f8 100644
--- a/src/server/mainwindow/mainwindow.h
+++ b/src/server/mainwindow/mainwindow.h
@@ -1,9 +1,7 @@
-#ifndef _MAINWINDOW_H_
-#define _MAINWINDOW_H_
+#ifndef PVS_MAINWINDOW_H_
+#define PVS_MAINWINDOW_H_
 
-#include <QtWidgets>
 #include <QMainWindow>
-#include "../net/client.h"
 
 class SessionNameWindow;
 class ConnectionFrame;
@@ -11,6 +9,11 @@ class ListenServer;
 class DiscoveryListener;
 class HelpWindow;
 class ReloadRoomWindow;
+class ClientLogin;
+class Client;
+class ClickLabel;
+
+class QLabel;
 
 namespace Ui
 {
@@ -27,8 +30,8 @@ class MainWindow : public QMainWindow
 
 public:
 
-	MainWindow(QWidget *parent = 0);
-	~MainWindow();
+	explicit MainWindow(QWidget *parent = nullptr);
+	~MainWindow() override;
 
 	QRect calcFrameGeometry(ConnectionFrame* frame) const;
 
@@ -38,24 +41,17 @@ private:
 	Ui::MainWindow    *ui;
 	SessionNameWindow *_sessionNameWindow;
 	HelpWindow        *_helpWindow;
-	ReloadRoomWindow	*_reloadWindow;
-	QLabel            *_sessionNameLabel;
-	int               _tbIconSize;
-	Qt::ToolBarArea   _tbArea;
+	ReloadRoomWindow  *_reloadWindow;
+	ClickLabel        *_sessionNameLabel;
 	int  _tilesX;
 	int  _tilesY;
 	QImage* _backgroundImage = nullptr;
 	QLabel* _examModeLabel = nullptr;
 
-
-	/* virtual columns to preserve the aspect ratio of the loaded room */
-	int _virtCols;
-	int _virtRows;
-
 	// Button block stuff
 	QTimer              *_buttonLockTimer;
 	QList<QAction*>     _lockingButtons;
-        static const qint64 BUTTON_BLOCK_TIME = 2000;
+	static const qint64 BUTTON_BLOCK_TIME = 2000;
 
 	// Management stuff
 	enum class Mode
@@ -66,19 +62,16 @@ private:
 	    LockedUnicast,
 	    None
 	} _mode;
-	int _streamingSource;
+	int _streamingSource{};
 
 	QList<ConnectionFrame*> _clientFrames;
         QWidget *_dropMarker;
-	ListenServer            *_listenServer;
-	DiscoveryListener       *_discoveryListener;
 
-	int _lastClientCount;
+	int _lastClientCount{};
 
-        QPoint closestFreeSlot(const QPoint preferredPixels, const ConnectionFrame* toIgnore);
+	QPoint closestFreeSlot(const QPoint &preferredPixels, const ConnectionFrame* toIgnore);
 	void placeFrameInFreeSlot(ConnectionFrame* frame, QPoint preferred = QPoint(-1, -1));
 	ConnectionFrame* createFrame(const QString &computerId = QString(), const QPoint *gridPosition = nullptr, bool fromRoomplan = false);
-	void savePosition(ConnectionFrame *cf);
 	void startVncServerIfNecessary(int from);
 	void tellClientCurrentSituation(Client* client);
 	void reset(bool lock = false);
@@ -86,19 +79,19 @@ private:
 	ConnectionFrame* getTutorFrame();
 	ConnectionFrame* getSelectedFrame();
 
-	void closeEvent(QCloseEvent *e);
-	void changeEvent(QEvent *e);
-	void resizeEvent(QResizeEvent *e);
-	void mouseReleaseEvent(QMouseEvent* e);
+	void closeEvent(QCloseEvent *e) override;
+	void changeEvent(QEvent *e) override;
+	void resizeEvent(QResizeEvent *e) override;
+	void mouseReleaseEvent(QMouseEvent* e) override;
 
 	int getTileWidthPx() const;
 	int getTileHeightPx() const;
 
-        void updateContextButtonStates();
+	void updateContextButtonStates();
 
 	void reloadCurrentRoom();
 
-        void vncOneOnOne(bool exclusive);
+	void vncOneOnOne(bool exclusive);
 
 protected slots:
 	void disableButtons();
@@ -126,8 +119,8 @@ protected slots:
 	void onButtonExit();
 	void onButtonHelp();
 	// connection frame
-        void onFrameMoving(ConnectionFrame* frame);
-        void onFrameDropped(ConnectionFrame* frame);
+	void onFrameMoving(ConnectionFrame* frame);
+	void onFrameDropped(ConnectionFrame* frame);
 	void onFrameClicked(ConnectionFrame* frame);
 	// Net
 	void onClientConnected(Client* client);
diff --git a/src/server/net/certmanager.cpp b/src/server/net/certmanager.cpp
index 5d8d824..968535a 100644
--- a/src/server/net/certmanager.cpp
+++ b/src/server/net/certmanager.cpp
@@ -18,19 +18,20 @@
 #define CERTSTORAGE ".config/openslx/pvs2/"
 
 #include "certmanager.h"
-#include <QMap>
+#include "../../shared/util.h"
+
+#include <QHash>
 #include <QDir>
 #include <QDebug>
 #include <QFileInfo>
-#include <QSettings>
 #include <QMessageBox>
-#include <QApplication>
-#include <cstdlib>
+#include <QProcess>
+#include <QCoreApplication>
 
 namespace CertManager
 {
-static QMap<QString, QSslCertificate> _certs;
-static QMap<QString, QSslKey> _keys;
+static QHash<QString, QSslCertificate> _certs;
+static QHash<QString, QSslKey> _keys;
 
 static void generateFiles(QString& key, QString& cert);
 static bool loadFiles(QString& keyFile, QString& certFile, QSslKey &key, QSslCertificate &cert);
@@ -44,7 +45,7 @@ bool getPrivateKeyAndCert(const QString &name, QSslKey &key, QSslCertificate &ce
 	}
 	QString certDir = QDir::homePath().append("/").append(CERTSTORAGE);
 	if (!QDir::root().mkpath(certDir)) {
-		certDir = QString("/tmp/") + QString::number(qrand()) + "-" + QString::number(qrand()) + "/";
+		certDir = QString("/tmp/") + QString::number(slxrand()) + "-" + QString::number(slxrand()) + "/";
 		QDir::root().mkpath(certDir);
 	}
 	QString certFile = certDir.append(name);
@@ -66,11 +67,11 @@ bool getPrivateKeyAndCert(const QString &name, QSslKey &key, QSslCertificate &ce
 
 void fatal()
 {
-	QMessageBox::critical(nullptr, QCoreApplication::trUtf8("OpenSSL error", "CertManager"),
-			QCoreApplication::trUtf8("Could not generate certificates for secure connections.\n"
+	QMessageBox::critical(nullptr, QObject::tr("OpenSSL error", "CertManager"),
+			QObject::tr("Could not generate certificates for secure connections.\n"
 			"PVS will not work.\n\n"
 			"Press OK to quit.", "CertManager"));
-	qApp->exit(1);
+	QCoreApplication::exit(1);
 }
 
 static bool loadFiles(QString& keyFile, QString& certFile, QSslKey &key, QSslCertificate &cert)
@@ -95,14 +96,18 @@ static bool loadFiles(QString& keyFile, QString& certFile, QSslKey &key, QSslCer
 
 static void generateFiles(QString& key, QString& cert)
 {
-	char tmp[1000];
-	remove(key.toLocal8Bit().data());
-	remove(cert.toLocal8Bit().data());
-	snprintf(tmp, 1000,
-			 "openssl req -x509 -nodes -days 5000 -newkey rsa:4096 -subj '/C=DE/ST=BaWue/L=Freiburg/CN=openslx.org' -keyout \"%s\" -out \"%s\"",
-			 key.toLocal8Bit().data(), cert.toLocal8Bit().data());
-	system(tmp);
-	snprintf(tmp, 1000, "chmod 0600 \"%s\" \"%s\"", key.toLocal8Bit().data(), cert.toLocal8Bit().data());
-	system(tmp);
+	QProcess p;
+	QFile::remove(key);
+	QFile::remove(cert);
+	p.setProcessChannelMode(QProcess::ForwardedChannels);
+	p.start(QStringLiteral("openssl"), {
+		"req", "-x509", "-nodes", "-days", "5000", "-newkey", "rsa:4096",
+		"-subj", "'/C=DE/ST=BaWue/L=Freiburg/CN=openslx.org'",
+		"-keyout", key, "-out", cert
+	});
+	p.waitForFinished();
+	p.start(QStringLiteral("chmod"), { "0600", key, cert });
+	p.waitForFinished(500);
 }
+
 }
diff --git a/src/server/net/client.cpp b/src/server/net/client.cpp
index 977eb84..08dfc9a 100644
--- a/src/server/net/client.cpp
+++ b/src/server/net/client.cpp
@@ -9,46 +9,46 @@
 #include "../serverapp/serverapp.h"
 #include "../../shared/settings.h"
 #include "../../shared/util.h"
+
 #include <QPixmap>
 #include <cassert>
 #include <QNetworkInterface>
+#include <QTcpSocket>
+#include <QSslSocket>
 
 #define CHALLENGE_LEN 20
 
 int Client::_clientIdCounter = 0;
-Client::Client(QTcpSocket* socket) : _socket(socket)
+Client::Client(QTcpSocket* socket)
+		: _socket(socket)
 {
 	assert(socket != nullptr);
-	_authed = 0;
-	_projectionSource = 0;
 	_desiredSource = NO_SOURCE;
-	_isActiveVncClient = false;
-	_vncPort = 0;
-	_isTutor = false;
-	_locked = false;
-	_wantsAttention = false;
-
+	_socket->setParent(this);
 	_id = ++_clientIdCounter;
 	//_ip = _socket->peerAddress().toString();
 	qDebug("*** Client %s created.", qPrintable(_socket->peerAddress().toString()));
 	// Connect important signals
-	connect(_socket, SIGNAL(disconnected()),
-	        this, SLOT(disconnect()));
-	connect(_socket, SIGNAL(error(QAbstractSocket::SocketError)),
-	        this, SLOT(disconnect()));
-	connect(_socket, SIGNAL(sslErrors(const QList<QSslError> &)),
-	        this, SLOT(disconnect()));
-	connect(_socket, SIGNAL(readyRead()),
-	        this, SLOT(onDataArrival()));
+	connect(_socket, &QTcpSocket::disconnected,
+	        this, &Client::disconnect);
+	connect(_socket, &QTcpSocket::errorOccurred,
+	        this, &Client::disconnect);
+	auto *ssl = qobject_cast<QSslSocket*>(_socket);
+	if (ssl != nullptr) {
+		connect(ssl, QOverload<const QList<QSslError> &>::of(&QSslSocket::sslErrors),
+				this, &Client::disconnect);
+	}
+	connect(_socket, &QTcpSocket::readyRead,
+	        this, &Client::onDataArrival);
 	// Send challenge
 	_challenge.resize(CHALLENGE_LEN);
 	for (int i = 0; i < CHALLENGE_LEN; ++i) {
-		_challenge[i] = char(qrand() & 0xff);
+		_challenge[i] = char(slxrand() & 0xff);
 	}
-	NetworkMessage msgChlng;
-	msgChlng.setField(_ID, _CHALLENGE);
-	msgChlng.setField(_CHALLENGE, _challenge);
-	msgChlng.writeMessage(_socket);
+	NetworkMessage msgChallenge;
+	msgChallenge.setField(_ID, _CHALLENGE);
+	msgChallenge.setField(_CHALLENGE, _challenge);
+	msgChallenge.writeMessage(_socket);
 	// give client 3 seconds to complete handshake
 	_timerIdAuthTimeout = startTimer(3000);
 	_timerPingTimeout = startTimer(3000);
@@ -58,7 +58,6 @@ Client::Client(QTcpSocket* socket) : _socket(socket)
 Client::~Client()
 {
 	qDebug() << "*** Client"  << _host  << " destroyed.";
-	_socket->deleteLater();
 }
 
 void Client::timerEvent(QTimerEvent* event)
@@ -302,7 +301,7 @@ void Client::stopVncClient()
  * Checks if client and manager runs on same machine.
  * @return Return true, if pvsmanager is running on client.
  */
-bool Client::isManagerMachine()
+bool Client::isManagerMachine() const
 {
 	foreach (const QHostAddress & address, QNetworkInterface::allAddresses())
 	if (address != QHostAddress(QHostAddress::LocalHost)
@@ -334,3 +333,8 @@ void Client::disconnect()
 	this->deleteLater();
 	emit disconnected();
 }
+
+QString Client::ip() const
+{
+	return _socket->peerAddress().toString();
+}
diff --git a/src/server/net/client.h b/src/server/net/client.h
index 3d5158b..3b95321 100644
--- a/src/server/net/client.h
+++ b/src/server/net/client.h
@@ -1,13 +1,13 @@
 #ifndef CLIENT_H_
 #define CLIENT_H_
 
-#include <QtCore>
-#include <QHostAddress>
-#include <QAbstractSocket>
-#include <QTcpSocket>
 #include "../../shared/networkmessage.h"
 
+#include <QByteArray>
+
 //class QSslSocket;
+class QTcpSocket;
+class Client;
 
 #define NO_SOURCE 0
 
@@ -26,32 +26,32 @@ class Client : public QObject
 
 public:
 	explicit Client(QTcpSocket* socket);
-	~Client();
+	~Client() override;
 
 	// Getters
-        inline bool     isAuthed() const { return _authed == 2; }
-	inline const QString& name() const { return _name; }
-	inline const QString& host() const { return _host; }
-	inline const QString  ip() const { return _socket->peerAddress().toString(); }
-        inline int      id() const { return _id; }
-        inline bool     isActiveVncClient() const { return _isActiveVncClient; }
-        inline bool     isActiveVncServer() const { return _vncPort > 0; }
-        inline bool     isLocked() const { return _locked; }
-        inline int      desiredProjectionSource() const { return _desiredSource; }
-        inline int      projectionSource() const { return _projectionSource; }
-        inline int      isExamMode() const { return _isExamMode; }
-        inline bool     wantsAttention() const { return _wantsAttention; }
-	inline void     removeAttention() { if (!_wantsAttention) return; removeAttentionInternal(); }
+	bool     isAuthed() const { return _authed == 2; }
+	const QString& name() const { return _name; }
+	const QString& host() const { return _host; }
+	QString  ip() const;
+	int      id() const { return _id; }
+	bool     isActiveVncClient() const { return _isActiveVncClient; }
+	bool     isActiveVncServer() const { return _vncPort > 0; }
+	bool     isLocked() const { return _locked; }
+	int      desiredProjectionSource() const { return _desiredSource; }
+	int      projectionSource() const { return _projectionSource; }
+	int      isExamMode() const { return _isExamMode; }
+	bool     wantsAttention() const { return _wantsAttention; }
+	void     removeAttention() { if (!_wantsAttention) return; removeAttentionInternal(); }
 
 	// Setters
-        inline void setTutor(bool enable) { _isTutor = enable; }
-	inline void setDesiredProjectionSource(int id) {_desiredSource = id;}
-	inline void setExamMode(bool mode) { _isExamMode = mode; }
+	void setTutor(bool enable) { _isTutor = enable; }
+	void setDesiredProjectionSource(int id) { _desiredSource = id; }
+	void setExamMode(bool mode) { _isExamMode = mode; }
 
 	//Send message stuff
 	void startVncServer();
 	void stopVncServer();
-	void startVncClient(Client const * const to );
+	void startVncClient(const Client * to);
 	void stopVncClient();
 	void lockScreen(bool);
 	void requestThumb(const QSize& size);
@@ -59,8 +59,8 @@ public:
 private:
 
 	QTcpSocket * const _socket;
-	bool           _locked;
-	int            _authed; // 0 = challenge sent, awaiting reply 1 = challenge ok, client challenge replied, awaiting login, 2 = ESTABLISHED
+	bool           _locked{};
+	int            _authed{}; // 0 = challenge sent, awaiting reply 1 = challenge ok, client challenge replied, awaiting login, 2 = ESTABLISHED
 	QString        _name;
 	QString        _host;
 	QByteArray     _challenge;
@@ -69,26 +69,26 @@ private:
 	int            _timerIdAuthTimeout, _timerPingTimeout;
 	int            _id; // this client's unique id
 	QString        _vncRwPass, _vncRoPass;
-	int            _vncPort; // VNCserver state. Greater 0 -> active on this port. Equals 0 -> no server.
+	int            _vncPort{}; // VNCserver state. Greater 0 -> active on this port. Equals 0 -> no server.
 	int            _desiredSource; // The source the client shall be connected to
-	int            _projectionSource; // The source the client was or is connected to (depends on _isActiveVncClient)
-	bool           _isActiveVncClient; // VNCclient state. indicating that the client is displaying a remote screen via VNC
-	bool           _isTutor; // Flag indicating that the client has been set as a tutor
-	bool		      _isExamMode;
-	bool           _wantsAttention; // Flag telling whether the client activated the "i want attention" button
+	int            _projectionSource{}; // The source the client was or is connected to (depends on _isActiveVncClient)
+	bool           _isActiveVncClient{}; // VNCclient state. indicating that the client is displaying a remote screen via VNC
+	bool           _isTutor{}; // Flag indicating that the client has been set as a tutor
+	bool           _isExamMode{};
+	bool           _wantsAttention{}; // Flag telling whether the client activated the "i want attention" button
 	QByteArray     _rawRemoteScreen;
 
 
 	static int     _clientIdCounter;
 
-	bool isManagerMachine();
+	bool isManagerMachine() const;
 
 	void handleMsg();
 	void sendMessage(NetworkMessage& message);
 	void removeAttentionInternal();
 
 protected:
-	void timerEvent(QTimerEvent* event);
+	void timerEvent(QTimerEvent* event) override;
 
 signals:
 	void authenticating(Client* client, ClientLogin* request);
diff --git a/src/server/net/discoverylistener.cpp b/src/server/net/discoverylistener.cpp
index b0f0df4..d644259 100644
--- a/src/server/net/discoverylistener.cpp
+++ b/src/server/net/discoverylistener.cpp
@@ -29,23 +29,20 @@
 /**
  * @brief DiscoveryListener::DiscoveryListener
  */
-DiscoveryListener::DiscoveryListener() :
-	_socket(this), _counterResetPos(0)
+DiscoveryListener::DiscoveryListener(QObject *parent)
+		: _socket(this)
 {
-	if (!_socket.bind(QHostAddress::AnyIPv4, SERVICE_DISCOVERY_PORT))
+	if (!_socket.bind(QHostAddress::AnyIPv4, SERVICE_DISCOVERY_PORT)) {
 		qFatal("Could not bind to service discovery port %d", int(SERVICE_DISCOVERY_PORT));
-	connect(&_socket, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
-	for (int i = 0; i < SD_PACKET_TABLE_SIZE; ++i)
-		_packetCounter[i] = 0;
+	}
+	connect(&_socket, &QUdpSocket::readyRead, this, &DiscoveryListener::onReadyRead);
 	startTimer((SPAM_MODERATE_AT_ONCE * SPAM_MODERATE_INTERVAL) / SD_PACKET_TABLE_SIZE + 1);
 }
 
 /**
  * @brief DiscoveryListener::~DiscoveryListener
  */
-DiscoveryListener::~DiscoveryListener()
-{
-}
+DiscoveryListener::~DiscoveryListener() = default;
 
 /**
  * @brief hash
@@ -57,8 +54,8 @@ static quint16 hash(const QHostAddress& host)
 	static quint16 seed1 = 0, seed2 = 0;
 	while (seed1 == 0) { // Make sure the algorithm uses different seeds each time the program is
 		// run to prevent hash collision attacks
-		seed1 = quint16(qrand() & 0xffff);
-		seed2 = quint16(qrand() & 0xffff);
+		seed1 = quint16(slxrand() & 0xffff);
+		seed2 = quint16(slxrand() & 0xffff);
 	}
 	quint8 data[16], len;
 	if (host.protocol() == QAbstractSocket::IPv4Protocol) {
@@ -79,8 +76,8 @@ static quint16 hash(const QHostAddress& host)
 	} else {
 		// Durr?
 		len = 2;
-		data[0] = quint8(qrand());
-		data[1] = quint8(qrand());
+		data[0] = quint8(slxrand());
+		data[1] = quint8(slxrand());
 	}
 	quint16 result = 0;
 	quint16 mod = seed1;
diff --git a/src/server/net/discoverylistener.h b/src/server/net/discoverylistener.h
index 64d4351..47a4295 100644
--- a/src/server/net/discoverylistener.h
+++ b/src/server/net/discoverylistener.h
@@ -8,12 +8,14 @@
 #ifndef DISCOVERYLISTENER_H_
 #define DISCOVERYLISTENER_H_
 
-#include <QtCore>
+#include <QObject>
 #include <QUdpSocket>
 #include "../../shared/networkmessage.h"
 
 #define SD_PACKET_TABLE_SIZE 20000
 
+class QTimerEvent;
+
 class DiscoveryListener : public QObject
 {
 	Q_OBJECT
@@ -21,16 +23,16 @@ class DiscoveryListener : public QObject
 private:
 	QUdpSocket _socket;
 	NetworkMessage _packet;
-	int _counterResetPos;
+	int _counterResetPos{};
 
-	quint8 _packetCounter[SD_PACKET_TABLE_SIZE]; // count packets per source address to ignore spammers
+	quint8 _packetCounter[SD_PACKET_TABLE_SIZE]{}; // count packets per source address to ignore spammers
 
 protected:
-	void timerEvent(QTimerEvent* event);
+	void timerEvent(QTimerEvent* event) override;
 
 public:
-	DiscoveryListener();
-	virtual ~DiscoveryListener();
+	explicit DiscoveryListener(QObject *parent);
+	~DiscoveryListener() override;
 
 private slots:
 	void onReadyRead();
diff --git a/src/server/net/filedownloader.cpp b/src/server/net/filedownloader.cpp
deleted file mode 100644
index b930869..0000000
--- a/src/server/net/filedownloader.cpp
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * FileDownloader.cpp
- *
- *  Created on: Mar 7, 2014
- *      Author: nils
- */
-
-#include <QFileInfo>
-
-#include "filedownloader.h"
-
-FileDownloader::FileDownloader(QObject *parent) :
-	QObject(parent)
-{
-	connect(&m_WebCtrl, SIGNAL(finished(QNetworkReply*)),
-	        SLOT(fileDownloaded(QNetworkReply*)));
-}
-
-FileDownloader::~FileDownloader()
-{
-
-}
-
-void FileDownloader::connectSlot(QObject* obj, const char* slot)
-{
-	QObject::connect(this, SIGNAL(downloaded(QByteArray&)),
-	                 obj, slot);
-}
-
-void FileDownloader::fileDownloaded(QNetworkReply* pReply)
-{
-	QByteArray downloadedData = pReply->readAll();
-	//emit a signal
-	pReply->deleteLater();
-	emit downloaded(downloadedData);
-}
-
-void FileDownloader::downloadFile(const QUrl& fileUrl)
-{
-	m_WebCtrl.get(QNetworkRequest(fileUrl));
-}
diff --git a/src/server/net/filedownloader.h b/src/server/net/filedownloader.h
deleted file mode 100644
index 227af50..0000000
--- a/src/server/net/filedownloader.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * filedownloader.h
- *
- *  Created on: Mar 7, 2014
- *      Author: nils
- */
-
-#ifndef FILEDOWNLOADER_H_
-#define FILEDOWNLOADER_H_
-
-#include <QObject>
-#include <QByteArray>
-#include <QNetworkAccessManager>
-#include <QNetworkRequest>
-#include <QNetworkReply>
-
-class FileDownloader : public QObject
-{
-	Q_OBJECT
-public:
-	explicit FileDownloader(QObject *parent = 0);
-
-	virtual ~FileDownloader();
-
-	void downloadFile(const QUrl& fileUrl);
-
-	void connectSlot(QObject* obj, const char* slot);
-
-	QByteArray downloadedData() const;
-
-signals:
-	void downloaded(QByteArray& downloadedData);
-
-private slots:
-
-	void fileDownloaded(QNetworkReply* pReply);
-
-private:
-
-	QNetworkAccessManager m_WebCtrl;
-
-};
-
-#endif /* FILEDOWNLOADER_H_ */
diff --git a/src/server/net/listenserver.cpp b/src/server/net/listenserver.cpp
index 0438fb4..27a1412 100644
--- a/src/server/net/listenserver.cpp
+++ b/src/server/net/listenserver.cpp
@@ -1,18 +1,20 @@
 #include "listenserver.h"
 #include "client.h"
+
 #include <QSslSocket>
 
-#define MAX_CLIENTS 50
 /**
  * Initialize listenServer to listen on specific port.
  * And connect Signal newConnection() with Slot newClientConnection().
  * @param port
  */
-ListenServer::ListenServer(quint16 port)
+ListenServer::ListenServer(quint16 port, QObject *parent)
+		: QObject(parent)
+		, _server(this)
 {
 	if (!_server.listen(QHostAddress::AnyIPv4, port) || !_server.isListening())
 		qFatal("Cannot bind to TCP port %d (incoming SSL clients)", int(port));
-	connect(&_server, SIGNAL(newConnection()), this, SLOT(newClientConnection()));
+	connect(&_server, &SslServer::newConnection, this, &ListenServer::newClientConnection);
 }
 
 ListenServer::~ListenServer()
@@ -32,7 +34,7 @@ void ListenServer::newClientConnection()
 {
 	QTcpSocket* sock;
 	while ((sock = _server.nextPendingConnection()) != nullptr) {
-		Client* client = new Client(sock); // TODO: what happens with disconnected clients
+		auto* client = new Client(sock); // TODO: what happens with disconnected clients
 		emit newClient(client);
 	}
 }
diff --git a/src/server/net/listenserver.h b/src/server/net/listenserver.h
index 640da23..4ad363d 100644
--- a/src/server/net/listenserver.h
+++ b/src/server/net/listenserver.h
@@ -18,8 +18,8 @@ private:
 	SslServer _server;
 
 public:
-	explicit ListenServer(quint16 port);
-	virtual ~ListenServer();
+	explicit ListenServer(quint16 port, QObject *parent);
+	~ListenServer() override;
 
 private slots:
 	void newClientConnection();
diff --git a/src/server/net/sslserver.cpp b/src/server/net/sslserver.cpp
index b2da034..2dfa84c 100644
--- a/src/server/net/sslserver.cpp
+++ b/src/server/net/sslserver.cpp
@@ -21,7 +21,9 @@
 #include "certmanager.h"
 #include <unistd.h>
 
-SslServer::SslServer() : QTcpServer(nullptr), _timer(new QTimer(this))
+SslServer::SslServer(QObject *parent)
+		: QTcpServer(parent)
+		, _timer(new QTimer(this))
 {
 	connect(_timer, &QTimer::timeout, [=]() {
 		if (_pending.empty())
@@ -43,9 +45,11 @@ SslServer::SslServer() : QTcpServer(nullptr), _timer(new QTimer(this))
 SslServer::~SslServer()
 {
 	_timer->stop();
-	for (QSslSocket *sock : _pending.keys()) {
+	auto keys = _pending.keys();
+	for (QSslSocket *sock : keys) {
 		sock->deleteLater();
 	}
+	_pending.clear();
 }
 
 /**
@@ -64,7 +68,7 @@ void SslServer::incomingConnection(qintptr socketDescriptor)
 		::close(int(socketDescriptor));
 		return;
 	}
-	QSslSocket *serverSocket = new QSslSocket(nullptr);
+	auto *serverSocket = new QSslSocket(nullptr);
 	connect(serverSocket, QOverload<const QList<QSslError> &>::of(&QSslSocket::sslErrors), this, &SslServer::sslErrors);
 	serverSocket->setPrivateKey(key);
 	serverSocket->setLocalCertificate(cert);
@@ -93,8 +97,8 @@ void SslServer::incomingConnection(qintptr socketDescriptor)
 void SslServer::sslErrors(const QList<QSslError>& errors)
 {
 	qDebug() << "Client caused sslErrors before connection:";
-	for (QList<QSslError>::const_iterator it = errors.begin(); it != errors.end(); it++) {
-		qDebug() << it->errorString();
+	for (const auto & error : errors) {
+		qDebug() << error.errorString();
 	}
 
 }
diff --git a/src/server/net/sslserver.h b/src/server/net/sslserver.h
index 03d947a..c74e56c 100644
--- a/src/server/net/sslserver.h
+++ b/src/server/net/sslserver.h
@@ -35,11 +35,11 @@ private slots:
 	void sslErrors ( const QList<QSslError> & errors );
 
 public:
-	explicit SslServer();
-	virtual ~SslServer();
+	explicit SslServer(QObject *parent);
+	~SslServer() override;
 
 protected:
-	void incomingConnection(qintptr handle);
+	void incomingConnection(qintptr handle) override;
 	QHash<QSslSocket*, qint64> _pending; // Queue for connected but unencrypted connections
 	QTimer* _timer;
 };
diff --git a/src/server/numerickeyboard/numerickeyboard.cpp b/src/server/numerickeyboard/numerickeyboard.cpp
index d819a58..e6677aa 100644
--- a/src/server/numerickeyboard/numerickeyboard.cpp
+++ b/src/server/numerickeyboard/numerickeyboard.cpp
@@ -1,10 +1,5 @@
-#include "src/server/numerickeyboard/numerickeyboard.h"
+#include "numerickeyboard.h"
 #include "ui_numerickeyboard.h"
-#include <iostream>
-
-using std::cout;
-using std::endl;
-
 
 NumericKeyboard::NumericKeyboard(QWidget *parent) :
 	QGroupBox(parent),
@@ -12,20 +7,20 @@ NumericKeyboard::NumericKeyboard(QWidget *parent) :
 {
 	ui->setupUi(this);
 	/* das geht leider nicht ? */
-//    connect(ui->button_0, SIGNAL (clicked(bool)), this, SLOT (relayDigit(0)));
+//    connect(ui->button_0, &QPushButton::clicked, this, &NumericKeyboard::relayDigit);
 
-	connect(ui->button_0, SIGNAL (clicked(bool)), this, SLOT (relayDigit0()));
-	connect(ui->button_1, SIGNAL (clicked(bool)), this, SLOT (relayDigit1()));
-	connect(ui->button_2, SIGNAL (clicked(bool)), this, SLOT (relayDigit2()));
-	connect(ui->button_3, SIGNAL (clicked(bool)), this, SLOT (relayDigit3()));
-	connect(ui->button_4, SIGNAL (clicked(bool)), this, SLOT (relayDigit4()));
-	connect(ui->button_5, SIGNAL (clicked(bool)), this, SLOT (relayDigit5()));
-	connect(ui->button_6, SIGNAL (clicked(bool)), this, SLOT (relayDigit6()));
-	connect(ui->button_7, SIGNAL (clicked(bool)), this, SLOT (relayDigit7()));
-	connect(ui->button_8, SIGNAL (clicked(bool)), this, SLOT (relayDigit8()));
-	connect(ui->button_9, SIGNAL (clicked(bool)), this, SLOT (relayDigit9()));
+	connect(ui->button_0, &QPushButton::clicked, this, &NumericKeyboard::relayDigit0);
+	connect(ui->button_1, &QPushButton::clicked, this, &NumericKeyboard::relayDigit1);
+	connect(ui->button_2, &QPushButton::clicked, this, &NumericKeyboard::relayDigit2);
+	connect(ui->button_3, &QPushButton::clicked, this, &NumericKeyboard::relayDigit3);
+	connect(ui->button_4, &QPushButton::clicked, this, &NumericKeyboard::relayDigit4);
+	connect(ui->button_5, &QPushButton::clicked, this, &NumericKeyboard::relayDigit5);
+	connect(ui->button_6, &QPushButton::clicked, this, &NumericKeyboard::relayDigit6);
+	connect(ui->button_7, &QPushButton::clicked, this, &NumericKeyboard::relayDigit7);
+	connect(ui->button_8, &QPushButton::clicked, this, &NumericKeyboard::relayDigit8);
+	connect(ui->button_9, &QPushButton::clicked, this, &NumericKeyboard::relayDigit9);
 
-	connect(ui->button_del, SIGNAL (clicked(bool)), this, SLOT(relayDelete()));
+	connect(ui->button_del, &QPushButton::clicked, this, &NumericKeyboard::relayDelete);
 }
 
 NumericKeyboard::~NumericKeyboard()
diff --git a/src/server/numerickeyboard/numerickeyboard.h b/src/server/numerickeyboard/numerickeyboard.h
index 3ece99c..6db3de3 100644
--- a/src/server/numerickeyboard/numerickeyboard.h
+++ b/src/server/numerickeyboard/numerickeyboard.h
@@ -14,7 +14,7 @@ class NumericKeyboard : public QGroupBox
 
 public:
 	explicit NumericKeyboard(QWidget *parent = 0);
-	~NumericKeyboard();
+	~NumericKeyboard() override;
 
 private:
 	Ui::NumericKeyboard *ui;
diff --git a/src/server/reloadroomwindow/reloadroomwindow.h b/src/server/reloadroomwindow/reloadroomwindow.h
index 2baf53f..67c2a94 100644
--- a/src/server/reloadroomwindow/reloadroomwindow.h
+++ b/src/server/reloadroomwindow/reloadroomwindow.h
@@ -16,7 +16,7 @@ class ReloadRoomWindow : public QDialog
 
 public:
 	explicit ReloadRoomWindow(QWidget *parent = nullptr);
-	~ReloadRoomWindow();
+	~ReloadRoomWindow() override;
 
     QDialogButtonBox* buttonBox() const;
 
diff --git a/src/server/serverapp/serverapp.cpp b/src/server/serverapp/serverapp.cpp
index 2cc237a..933517b 100644
--- a/src/server/serverapp/serverapp.cpp
+++ b/src/server/serverapp/serverapp.cpp
@@ -1,15 +1,15 @@
 #include <QTranslator>
 #include <QNetworkInterface>
+#include <QSettings>
+#include <QLibraryInfo>
 
 #include "serverapp.h"
+#include "../../shared/util.h"
 
 static QSize minimalGridSize(const QMap<QString, QPoint>& clientPositions, QSize& clientSize);
 
 ServerApp::ServerApp(int& argc, char** argv)
-	: QApplication(argc, argv),
-		_mainWindow(nullptr),
-		_managerOnly(false),
-		_isExam(false)
+	: QApplication(argc, argv)
 {
 	setOrganizationName("openslx");
 	setOrganizationDomain("openslx.org");
@@ -22,19 +22,19 @@ ServerApp::ServerApp(int& argc, char** argv)
 	// If started in manager-only mode, and there is no current room
 	// after reading the config, exit right away
 	if (_managerOnly && _currentRoom == "") {
-		::exit(0);
+		QApplication::exit(0);
 		return;
 	}
 
 	// System strings
-	QTranslator *qtTranslator = new QTranslator(this);
+	auto *qtTranslator = new QTranslator(this);
 	if (!qtTranslator->load(QLocale::system(), "qt", "_", QLibraryInfo::location(QLibraryInfo::TranslationsPath))) {
 		qDebug() << "Loading system translations failed" << QLibraryInfo::location(QLibraryInfo::TranslationsPath);
 	} else {
 		installTranslator(qtTranslator);
 	}
 	// App specific
-	QTranslator *translator = new QTranslator(this);
+	auto *translator = new QTranslator(this);
 	if (!translator->load(QLocale::system(), ":", "l_")) {
 		qDebug() << "Loading app translations failed";
 	} else {
@@ -43,20 +43,20 @@ ServerApp::ServerApp(int& argc, char** argv)
 
 	/* Set the global path of the settings */
 	QSettings::setPath(QSettings::IniFormat, QSettings::SystemScope, "/opt/");
-	QSharedPointer<QSettings> sys = getSettings();
+	QSettings* sys = getSettings();
 	qDebug() << "System settings are in:" << sys->fileName();
 
-	_mainWindow = new MainWindow();
+	new MainWindow();
 }
 
 QStringList ServerApp::parseParameters()
 {
 	QStringList rest;
-	for (QString a : QApplication::arguments()) {
-		if (a == "--manager-only") {
+	for (const QString& a : QApplication::arguments()) {
+		if (a == QStringLiteral("--manager-only")) {
 			_managerOnly = true;
 			break;
-		} else if (a.startsWith("--config=")) {
+		} else if (a.startsWith(QStringLiteral("--config="))) {
 			_iniPath = a.mid(9);
 		} else {
 			rest << a;
@@ -73,17 +73,20 @@ QStringList ServerApp::arguments()
 
 void ServerApp::loadRooms()
 {
-	QSharedPointer<QSettings> conf = getSettings();
+	QSettings* conf = getSettings();
 
-	if (!conf->contains("rooms")) { qDebug() << "Invalid config file (no rooms are set)!"; return; }
+	if (!conf->contains(QStringLiteral("rooms"))) {
+		qDebug() << "Invalid config file (no rooms are set)!";
+		return;
+	}
 	QStringList rooms = conf->value("rooms").toStringList();
 
-	for (QString roomId : rooms) {
+	for (const QString& roomId : rooms) {
 		conf->beginGroup(roomId);
 		QString roomName = conf->value("name").toString();
 
 		/* fallback to the old format where the room id was actually just the name */
-		if (roomName == "") {
+		if (roomName.isEmpty()) {
 			roomName = roomId;
 		}
 		if (!conf->contains("mgrIP")) {
@@ -114,8 +117,8 @@ void ServerApp::loadRooms()
 		}
 
 		foreach (const QHostAddress & address, QNetworkInterface::allAddresses()) {
-			if (address != QHostAddress(QHostAddress::LocalHost) && mgrIP == address.toString()) {
-				qDebug("Found this ip in config.");
+			if (!address.isBroadcast() && !address.isLoopback() && !address.isMulticast() && mgrIP == address.toString()) {
+				qDebug() << "Found own ip in config.";
 				_currentRoom = roomName;
 			}
 		}
@@ -133,18 +136,17 @@ void ServerApp::loadRooms()
 	}
 }
 
-const Room* ServerApp::getCurrentRoom()
+const Room* ServerApp::getCurrentRoom() const
 {
-	if (_rooms.contains(_currentRoom)) {
-		return _rooms[_currentRoom];
-	} else {
-		static Room* defaultRoom = nullptr;
-		if (defaultRoom == nullptr) {
-			defaultRoom = new Room(QMap<QString,
-			                       QPoint>(), QSize(8, 6), QSize(1, 1), "", "");
-		}
-		return defaultRoom;
+	auto *room = _rooms.value(_currentRoom);
+	if (room != nullptr)
+		return room;
+	static Room* defaultRoom = nullptr;
+	if (defaultRoom == nullptr) {
+		defaultRoom = new Room(QMap<QString,
+							   QPoint>(), QSize(8, 6), QSize(1, 1), "", "");
 	}
+	return defaultRoom;
 }
 void ServerApp::setSessionName(const QString& name)
 {
@@ -154,20 +156,20 @@ void ServerApp::setSessionName(const QString& name)
 
 void ServerApp::setSessionName()
 {
-	const QString name = QString::number(qrand() % 9000 + 1000);
+	const QString name = QString::number(slxrand() % 9000 + 1000);
 	_sessionName = name;
 	_sessionNameArray = name.toUtf8();
 }
 
-QSharedPointer<QSettings> ServerApp::getSettings()
+QSettings * ServerApp::getSettings()
 {
-	QSharedPointer<QSettings> set;
-	if (_iniPath == "") {
+	QSettings *set;
+	if (_iniPath.isEmpty()) {
 		/* default location (system scope) */
-		set = QSharedPointer<QSettings>(new QSettings(QSettings::IniFormat, QSettings::SystemScope, "openslx/pvs2", "pvs2"));
+		set = new QSettings(QSettings::IniFormat, QSettings::SystemScope, "openslx/pvs2", "pvs2", this);
 	} else {
 		/* use _iniPath to find ini file */
-		set = QSharedPointer<QSettings>(new QSettings(_iniPath, QSettings::IniFormat));
+		set = new QSettings(_iniPath, QSettings::IniFormat, this);
 	}
 	set->setIniCodec("UTF-8");
 	return set;
@@ -182,14 +184,15 @@ static QSize minimalGridSize(const QMap<QString, QPoint>& clientPositions, QSize
 	int x = 0;
 	int y = 0;
 
-	for (auto it = clientPositions.begin(); it != clientPositions.end(); ++it) {
-		QPoint pos = it.value();
-		if (pos.x() > x) { x = pos.x(); }
-		if (pos.y() > y) { y = pos.y(); }
-
+	for (const auto &pos : clientPositions) {
+		if (pos.x() > x) {
+			x = pos.x();
+		}
+		if (pos.y() > y) {
+			y = pos.y();
+		}
 	}
 	/* need a little extra space */
-	QSize size(x + clientSize.width(), y + clientSize.height());
-	return size;
+	return QSize(x + clientSize.width(), y + clientSize.height());
 }
 
diff --git a/src/server/serverapp/serverapp.h b/src/server/serverapp/serverapp.h
index e0a1351..b2b16c5 100644
--- a/src/server/serverapp/serverapp.h
+++ b/src/server/serverapp/serverapp.h
@@ -1,14 +1,16 @@
 #ifndef SERVERAPP_H
 #define SERVERAPP_H
 
+#include "../mainwindow/mainwindow.h"
+
 #include <QApplication>
 #include <QStringList>
 #include <QMap>
 
-#include "../mainwindow/mainwindow.h"
+class QSettings;
 
 struct Room {
-	Room(QMap<QString, QPoint> cPos, QSize grid, QSize client, QString image, QString tutor) :
+	Room(const QMap<QString, QPoint> &cPos, const QSize &grid, const QSize &client, const QString &image, const QString &tutor) :
 		clientPositions(cPos),
 		gridSize(grid),
 		clientSize(client),
@@ -23,12 +25,12 @@ struct Room {
 
 
 /* define a macro `serverApp` that can be used anywhere in the program and
- * returns a reference to the current ClientApp instance */
+ * returns a reference to the current ServerApp instance */
 
 #if defined(serverApp)
 #undef serverApp
 #endif
-#define serverApp (static_cast<ServerApp*>(QCoreApplication::instance()))
+#define serverApp (static_cast<ServerApp*>(QCoreApplication::instance())) // NOLINT(cppcoreguidelines-pro-type-static-cast-downcast)
 
 /* this class is supposed to (after complete refactoring) to encapsulate all
  * state of the application.  At the moment, the state is distributed within
@@ -42,15 +44,14 @@ class ServerApp : public QApplication
 
 private:
 	QStringList _arguments;
-	MainWindow* _mainWindow;
 
 	QString _sessionName;
 	QByteArray _sessionNameArray;
 	QMap<QString, Room*> _rooms;
 	QString _currentRoom;
 
-	bool _managerOnly;
-	bool _isExam;
+	bool _managerOnly{};
+	bool _isExam{};
 	QString _iniPath;
 
 	QStringList parseParameters();
@@ -64,20 +65,16 @@ public:
 
 
 	/* getters */
-	const QString& sessionName() 		    { return _sessionName; }
-	const QByteArray& sessionNameArray()    { return _sessionNameArray; }
-	const QMap<QString, Room*> & rooms()    { return _rooms; }
-	const QString& getCurrentRoomName()     { return _currentRoom; }
-	const QMap<QString, Room*>& getRooms()  { return _rooms; }
-	bool isExam() 							{ return _isExam; }
-	bool isManagerOnly()					{ return _managerOnly; }
-	const Room* getCurrentRoom();
-	QSharedPointer<QSettings> getSettings();
+	const QString &sessionName() const            { return _sessionName; }
+	const QByteArray &sessionNameArray() const    { return _sessionNameArray; }
+	const QMap<QString, Room *> &getRooms() const { return _rooms; }
+	bool isExam() const                           { return _isExam; }
+	const Room* getCurrentRoom() const;
+	QSettings * getSettings();
 
 	/* setters */
 	void setSessionName(const QString& name);
 	void setSessionName();
-	void setIniPath(QString s) { _iniPath = s; };
 	void setCurrentRoom(const QString& room) { _currentRoom = room; }
 	void setExam(bool exam) { _isExam = exam; }
 
diff --git a/src/server/sessionnamewindow/sessionnamewindow.cpp b/src/server/sessionnamewindow/sessionnamewindow.cpp
index f79efbf..74aa05d 100644
--- a/src/server/sessionnamewindow/sessionnamewindow.cpp
+++ b/src/server/sessionnamewindow/sessionnamewindow.cpp
@@ -9,32 +9,30 @@
  #
  # General information about OpenSLX can be found at http://openslx.org/
  # -----------------------------------------------------------------------------
- # mainWindow.cpp
- This is the Main class for the pvsManager. The GUI is contructed here.
- # -----------------------------------------------------------------------------
  */
 
-#include <QtWidgets>
 #include "sessionnamewindow.h"
+#include "ui_sessionnamewindow.h"
 #include "../serverapp/serverapp.h"
 #include "../numerickeyboard/numerickeyboard.h"
-#include "ui_sessionnamewindow.h"
-
+#include "../../shared/util.h"
 
-SessionNameWindow::SessionNameWindow(QWidget *parent) :
-	QDialog(parent), ui(new Ui::SessionName)
+#include <QCloseEvent>
 
+SessionNameWindow::SessionNameWindow(QWidget *parent)
+		: QDialog(parent)
+		, ui(new Ui::SessionName)
 {
 	ui->setupUi(this);
-	connect(ui->bboxOkCancel, SIGNAL(accepted()),  this, SLOT(onOkClicked()));
-	connect(ui->bboxOkCancel, SIGNAL(rejected()), this, SLOT(close()));
-	connect(ui->cmdRandom, SIGNAL(clicked(bool)), this, SLOT(onGenerateRandomName()));
+	connect(ui->bboxOkCancel, &QDialogButtonBox::accepted,  this, &SessionNameWindow::onOkClicked);
+	connect(ui->bboxOkCancel, &QDialogButtonBox::rejected, this, &SessionNameWindow::close);
+	connect(ui->cmdRandom, &QPushButton::clicked, this, &SessionNameWindow::onGenerateRandomName);
 
 	/* add a virtual numeric keyboard */
-	NumericKeyboard *keyboard = new NumericKeyboard();
+	auto *keyboard = new NumericKeyboard();
 	ui->keyboard_placeholder->addWidget(keyboard);
-	connect(keyboard, SIGNAL(digitTyped(int)), this, SLOT(onDigitTyped(int)));
-	connect(keyboard, SIGNAL(digitDelete()), this, SLOT(onDigitDelete()));
+	connect(keyboard, &NumericKeyboard::digitTyped, this, &SessionNameWindow::onDigitTyped);
+	connect(keyboard, &NumericKeyboard::digitDelete, this, &SessionNameWindow::onDigitDelete);
 
 }
 
@@ -73,7 +71,7 @@ void SessionNameWindow::onOkClicked()
 
 void SessionNameWindow::onGenerateRandomName()
 {
-	ui->lineEditName->setText(QString::number(qrand() % 9000 + 1000));
+	ui->lineEditName->setText(QString::number(slxrand() % 9000 + 1000));
 }
 
 /** deletes the last digit of the saved sessionname */
diff --git a/src/server/sessionnamewindow/sessionnamewindow.h b/src/server/sessionnamewindow/sessionnamewindow.h
index e46b895..024df48 100644
--- a/src/server/sessionnamewindow/sessionnamewindow.h
+++ b/src/server/sessionnamewindow/sessionnamewindow.h
@@ -1,8 +1,7 @@
-#ifndef _SESSIONNAMEWINDOW_H_
-#define _SESSIONNAMEWINDOW_H_
-
-#include <QtWidgets>
+#ifndef PVS_SESSIONNAMEWINDOW_H_
+#define PVS_SESSIONNAMEWINDOW_H_
 
+#include <QDialog>
 
 namespace Ui
 {
@@ -17,13 +16,13 @@ private:
 	Ui::SessionName *ui;
 
 public:
-	SessionNameWindow(QWidget *parent = 0);
-	~SessionNameWindow();
+	explicit SessionNameWindow(QWidget *parent = nullptr);
+	~SessionNameWindow() override;
 
 	void show(const QString& name);
 
 protected:
-	void closeEvent(QCloseEvent *e);
+	void closeEvent(QCloseEvent *e) override;
 
 private slots:
 	void onOkClicked();
diff --git a/src/shared/networkmessage.h b/src/shared/networkmessage.h
index c072070..327f544 100644
--- a/src/shared/networkmessage.h
+++ b/src/shared/networkmessage.h
@@ -12,7 +12,9 @@
 #define NM_READ_INCOMPLETE (2)
 #define NM_READ_FAILED (0)
 
-#include <QtCore>
+#include <QHostAddress>
+#include <QByteArray>
+#include <QString>
 
 class QAbstractSocket;
 class QUdpSocket;
@@ -62,16 +64,16 @@ private:
 public:
 	NetworkMessage();
 	virtual ~NetworkMessage();
-	int readMessage(QAbstractSocket* socket);
+	int readMessage(QAbstractSocket *socket);
 	int readMessage(char* data, quint32 len);
-	bool writeMessage(QAbstractSocket * const socket);
+	bool writeMessage(QAbstractSocket *socket);
 	bool writeMessage(QUdpSocket* socket, const QHostAddress& address, quint16 port);
 	void reset() { _fields.clear(); _bufferSize = 0; _mode = 0; }
-	bool readComplete() { return _mode == 3; }
-	bool writeComplete() { return _mode == 4; }
+	bool readComplete() const { return _mode == 3; }
+	bool writeComplete() const { return _mode == 4; }
 	bool hasField(QByteArray& key) { return _fields.contains(key); }
-	const QString getFieldString(const QByteArray& key) const { return QString::fromUtf8(_fields.value(key)); }
-	const QByteArray getFieldBytes(const QByteArray& key) const { return _fields.value(key); }
+	QString getFieldString(const QByteArray& key) const { return QString::fromUtf8(_fields.value(key)); }
+	QByteArray getFieldBytes(const QByteArray& key) const { return _fields.value(key); }
 	void setField(const QByteArray& key, const QByteArray& value) { if (_mode == 1 || _mode == 2) qFatal("setField called in bad state."); _fields.insert(key, value); _mode = 0; }
 	void setField(const QByteArray& key, const QString& value) { setField(key, value.toUtf8()); }
 	// Convenience
diff --git a/src/shared/util.cpp b/src/shared/util.cpp
index d5c101e..880ffca 100644
--- a/src/shared/util.cpp
+++ b/src/shared/util.cpp
@@ -10,7 +10,7 @@
 
 static QCryptographicHash sha1(QCryptographicHash::Sha1);
 
-QByteArray genSha1(const QByteArray* a, const QByteArray* b, const QByteArray* c, const QByteArray* d, const QByteArray* e)
+QByteArray genSha1(const QByteArray *a, const QByteArray *b, const QByteArray *c, const QByteArray *d, const QByteArray *e)
 {
 	sha1.reset();
 	sha1.addData(*a);
diff --git a/src/shared/util.h b/src/shared/util.h
index e9530a8..c25f778 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -9,7 +9,10 @@
 #define UTIL_H_
 
 #include <QByteArray>
+#include <QRandomGenerator>
 
-QByteArray genSha1(const QByteArray* a, const QByteArray* b = nullptr, const QByteArray* c = nullptr, const QByteArray* d = nullptr, const QByteArray* e = nullptr);
+#define slxrand() (QRandomGenerator::system()->generate())
+
+QByteArray genSha1(const QByteArray *a, const QByteArray *b = nullptr, const QByteArray *c = nullptr, const QByteArray *d = nullptr, const QByteArray *e = nullptr);
 
 #endif /* UTIL_H_ */