From 7688ba080c0c69508847fca9aa36dc392ddbb766 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Thu, 8 Feb 2018 12:02:00 +0100
Subject: Support regex mangling of username before passing to lightdm

---
 src/loginform.cpp   | 10 +++++++-
 src/loginform.h     |  1 +
 src/namereplace.cpp | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/namereplace.h   | 13 ++++++++++
 4 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 src/namereplace.cpp
 create mode 100644 src/namereplace.h

diff --git a/src/loginform.cpp b/src/loginform.cpp
index 823958d..a43e9a8 100644
--- a/src/loginform.cpp
+++ b/src/loginform.cpp
@@ -20,6 +20,7 @@
 #include "ui_loginform.h"
 #include "settings.h"
 #include "global.h"
+#include "namereplace.h"
 
 LoginForm::LoginForm(QWidget *parent) :
     QWidget(parent), 
@@ -73,12 +74,19 @@ void LoginForm::initialize()
         connect(Global::greeter(), SIGNAL(authenticationComplete()), this, SLOT(onAuthenticationComplete()));
     }
 
+	// Load regexp for name substitution
+	NameReplace::loadSubs();
+
     ui->leaveComboBox->setDisabled(ui->leaveComboBox->count() <= 1);
     ui->passwordInput->clear();
 }
 
 void LoginForm::startAuthentication()
 {
+	QString username(ui->userInput->text());
+	NameReplace::replace(username);
+	std::cerr << "Logging in as " << username.toStdString() << std::endl;
+
     if (Global::testMode()) {
         return;
     }
@@ -99,7 +107,7 @@ void LoginForm::startAuthentication()
     ui->userInput->setEnabled(false);
     ui->passwordInput->setEnabled(false);
     cancelLoginTimer.start();
-    Global::greeter()->authenticate(ui->userInput->text());
+	Global::greeter()->authenticate(username);
 }
 
 void LoginForm::onPrompt(QString prompt, QLightDM::Greeter::PromptType promptType)
diff --git a/src/loginform.h b/src/loginform.h
index e414d2b..83ddd28 100644
--- a/src/loginform.h
+++ b/src/loginform.h
@@ -50,6 +50,7 @@ protected:
 
 private:
     void initialize();
+	void loadSubs();
     void addLeaveEntry(bool canDo, QString iconName, QString text, QString actionName);
     QString currentSession();
     void setCurrentSession(QString session);
diff --git a/src/namereplace.cpp b/src/namereplace.cpp
new file mode 100644
index 0000000..36d834d
--- /dev/null
+++ b/src/namereplace.cpp
@@ -0,0 +1,69 @@
+#include "namereplace.h"
+#include <QString>
+#include <QRegularExpression>
+#include <QFile>
+#include <QTextStream>
+#include <QDebug>
+
+#define SOURCE_FILE "/opt/openslx/lightdm/login-regexp"
+
+static QList< QPair< QRegularExpression, QString > > list;
+
+static inline int find(QChar c, int start, const QString& line)
+{
+	do {
+		int next = line.indexOf(c, start);
+		if (next == -1)
+			return -1;
+		if (line.at(next - 1) != '\\')
+			return next;
+		start = next + 1;
+	} while (true);
+}
+
+void NameReplace::loadSubs()
+{
+	int idx = 0;
+	QFile inputFile(SOURCE_FILE);
+	if (!inputFile.open(QIODevice::ReadOnly))
+		return;
+	QTextStream in(&inputFile);
+	in.setCodec("UTF-8");
+	while (!in.atEnd()) {
+		QString line = in.readLine();
+		idx++;
+		if (line.isEmpty())
+			continue;
+		QChar delim = line.at(0);
+		int first = find(delim, 1, line);
+		if (first == -1)
+			continue;
+		int second = find(delim, first + 1, line);
+		if (second == -1)
+			continue;
+		QString regex = line.mid(1, first - 1).replace(QString("\\") + delim, QString(delim));
+		QString replace = line.mid(first + 1, second - first - 1).replace(QString("\\") + delim, QString(delim));
+		QString flags = line.mid(second + 1);
+		// ...
+		QRegularExpression::PatternOptions opts = 0;
+		if (flags.contains("i")) {
+			opts |= QRegularExpression::CaseInsensitiveOption;
+		}
+		QRegularExpression re(regex, opts);
+		if (!re.isValid()) {
+			qWarning() << "Invalid regex:" << regex << "on line" << idx;
+			continue;
+		}
+		list.append(QPair<QRegularExpression, QString>(re, replace));
+	}
+	inputFile.close();
+}
+
+void NameReplace::replace(QString& input)
+{
+	if (list.isEmpty())
+		return;
+	for (auto &brumm : list) {
+		input = input.replace(brumm.first, brumm.second);
+	}
+}
diff --git a/src/namereplace.h b/src/namereplace.h
new file mode 100644
index 0000000..2b8e802
--- /dev/null
+++ b/src/namereplace.h
@@ -0,0 +1,13 @@
+#ifndef NAMEREPLACE_H
+#define NAMEREPLACE_H
+
+#include <QString>
+
+class NameReplace
+{
+public:
+	static void loadSubs();
+	static void replace(QString& input);
+};
+
+#endif
-- 
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