smsub/SMSubServer.cpp

/*****************************************************************************
* smsub Server Manager Subprocess
* Copyright (C) 2020 Syping
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* This software is provided as-is, no warranties are given to you, we are not
* responsible for anything with use of the software, you are self responsible.
*****************************************************************************/

#include <QCoreApplication>
#include <QTimer>
#include <QUuid>
#include "SMSubServer.h"
#include "smsub.h"

SMSubServer::SMSubServer(SMSubServerSettings *serverSettings, const QString &socket) : serverSettings(serverSettings)
{
    setSocketOptions(QLocalServer::UserAccessOption | QLocalServer::GroupAccessOption);
    listen(socket);
}

void SMSubServer::incomingConnection(quintptr socketDescriptor)
{
    QLocalSocket *socket = new QLocalSocket();
    socket->setSocketDescriptor(socketDescriptor);
    QObject::connect(socket, &QLocalSocket::readyRead, this, &SMSubServer::readyRead);
    QObject::connect(socket, &QLocalSocket::disconnected, this, &SMSubServer::deleteSocket);

    // Set authentication state
    if (serverSettings->isLocal) {
        socket->setProperty("Authenticated", true);
        sockets << socket;
    }
    else {
        socket->setProperty("Authenticated", false);
    }

    // Initial open writing
    socket->write(QString("SMSub Version %1\n").arg(QCoreApplication::applicationVersion()).toUtf8());
}

void SMSubServer::readyRead()
{
    // Manage client input
    QLocalSocket *socket = (QLocalSocket*)sender();
    bool isAuthenticated = socket->property("Authenticated").toBool();
    while (socket->canReadLine()) {
        const QByteArray readData = socket->readLine().trimmed();

        // Only allow commands being sent if authenticated
        if (likely(isAuthenticated)) {
            if (readData.startsWith("+dbg")) {
                socket->setProperty("ReceiveDbgMsg", true);
                socket->write("Debug messages enabled!\n");
            }
            else if (readData.startsWith("-dbg")) {
                socket->setProperty("ReceiveDbgMsg", false);
                socket->write("Debug messages disabled!\n");
            }
            else if (readData.startsWith("+log")) {
                socket->setProperty("ReceiveLog", true);
                debugOutput(socket, "Log output enabled!");
            }
            else if (readData.startsWith("-log")) {
                socket->setProperty("ReceiveLog", false);
                debugOutput(socket, "Log output disabled!");
            }
            else if (readData.startsWith("+reg")) {
                if (likely(serverSettings->canRegister)) {
                    QByteArray authUuid = QUuid::createUuid().toByteArray(QUuid::Id128);
                    authUuid = QByteArray::fromHex(authUuid).toBase64(QByteArray::OmitTrailingEquals);
                    emit tokenRegistered(QString::fromUtf8(authUuid));
                    socket->write("Token: " + authUuid + '\n');
                }
                else {
                    socket->write("Permission denied!\n");
                }
            }
            else if (readData.startsWith("kill")) {
                emit killRequested();
                debugOutput(socket, "Killing server!");
            }
            else if (readData.startsWith("stop")) {
                emit stopRequested();
                debugOutput(socket, "Stopping server!");
            }
            else if (readData.startsWith("wl")) {
                const QByteArray writeData = readData.mid(3);
                emit inputWritten(writeData + '\n');
                debugOutput(socket, "Write line \"" + writeData + "\"!");
            }
            else if (readData.startsWith("w")) {
                const QByteArray writeData = readData.mid(2);
                emit inputWritten(writeData);
                debugOutput(socket, "Write \"" + writeData + "\"!");
            }
        }
        else {
            // Authenticate when token is valid, otherwise disconnect
            if (unlikely(tokens.contains(QString::fromUtf8(readData)))) {
                // Set client as authenticated and add it to vector
                socket->setProperty("Authenticated", true);
                socket->write("Login successful!\n");
                isAuthenticated = true;
                sockets << socket;
            }
            else {
                // Stop receiving data and disconnect socket
                QObject::disconnect(socket, &QLocalSocket::readyRead, this, &SMSubServer::readyRead);
                socket->write("Incorrect token!\n");
                socket->disconnectFromServer();
                return;
            }
        }
    }
}

void SMSubServer::deleteSocket()
{
    // Delete socket and remove from index
    QLocalSocket *socket = (QLocalSocket*)sender();
    sockets.removeAll(socket);
    socket->deleteLater();
}

void SMSubServer::debugOutput(QLocalSocket *socket, const QByteArray &message)
{
    // Only send debug messages when the client opted-in
    const QVariant variant = socket->property("ReceiveDbgMsg");
    if (unlikely(variant.type() == QVariant::Bool)) {
        bool receiveDbgMsg = variant.toBool();
        if (likely(receiveDbgMsg)) {
            socket->write(message + '\n');
        }
    }
}

void SMSubServer::writeOutput(const QByteArray &output)
{
    // Read process output when client opted-in for log
    QVector<QLocalSocket*>::const_iterator it = sockets.constBegin();
    QVector<QLocalSocket*>::const_iterator end = sockets.constEnd();
    while (it != end) {
        const QVariant variant = (*it)->property("ReceiveLog");
        if (unlikely(variant.type() == QVariant::Bool)) {
            bool receiveLog = variant.toBool();
            if (likely(receiveLog)) {
                (*it)->write(output);
            }
        }
        it++;
    }
}

void SMSubServer::registerToken(const QString &token)
{
    // Register temporary token for a secure remote connection
    tokens << token;
    QTimer::singleShot(30000, [this, token]() {
        tokens.removeAll(token);
    });
}