vncserver.cpp

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/*
 * vncserver.cpp
 *
 *  Created on: 24.01.2013
 *      Author: sr
 */


#include <QGuiApplication>
#include <QProcess>
#include <QScreen>
#include "vncserver.h"
#include "../util/util.h"
#include "../../shared/util.h"

// Remove in future - see util.h
#undef errorOccurred

VncServer* VncServer::me = nullptr;

VncServer* VncServer::instance()
{
   if (me == nullptr)
      me = new VncServer();
   return me;
}

static QString makePassword(int len = 10)
{
   QString ret(len, Qt::Uninitialized);
   for (int i = 0; i < len; ++i)
      ret[i] = QChar(43 + slxrand() % 80);
   return ret;
}

struct Sleeper : public QThread {
   static void msleep(unsigned long msecs) { QThread::msleep(msecs); }
};

VncServer::VncServer() : _process(nullptr), _port(0), _timerId(0) {}

VncServer::~VncServer() = default;

QSharedPointer<QFile> VncServer::createPwFile(const QDir& dir)
{
   QDir::root().mkpath(dir.absolutePath());
   QString str(dir.absoluteFilePath("vncpass"));
   QSharedPointer<QFile> file = QSharedPointer<QFile>(new QFile(str));
   if (file->exists()) {
      file->remove();
   }
   file->open(QIODevice::WriteOnly);
   return file;
}

void VncServer::start()
{
   // Keep things clean
   if (_process != nullptr) {
      _process->blockSignals(true);
      _process->kill();
   }
   this->stop();
   // Generate passwords
   _rwpass = makePassword();
   _ropass = makePassword();
   // Create new password file
   QSharedPointer<QFile> pwhandle = createPwFile(Util::settingsDir());
   if (!pwhandle->isOpen()) {
      pwhandle = createPwFile(QDir("/tmp"));
   }
   if (!pwhandle->isOpen()) {
      qDebug() << "Could not open " << pwhandle->fileName() << " for writing";
      emit started(0, _ropass, _rwpass);
      return;
   }
   pwhandle->setPermissions(QFile::ReadOwner | QFile::WriteOwner);
   pwhandle->write(_rwpass.toUtf8().constData());
   pwhandle->write("\n");
   pwhandle->write(_ropass.toUtf8().constData());
   pwhandle->write("\n");
   pwhandle->close();
   // Create new process
   _process = new QProcess(this);
   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" << (QStringLiteral("rm:") + pwhandle->fileName());
   args << "-shared";
   args << "-repeat";
   args << "-autoport" << QString::number(54112);

   // Get rect of primary screen
    const QRect primaryRect = QGuiApplication::primaryScreen()->geometry();

   // Tell x11vnc to just use primary screen
   args << "-clip";
   QString rect;
   rect = QString::number(primaryRect.width())
          + "x" + QString::number(primaryRect.height())
          + "+" + QString::number(primaryRect.x())
          + "+" + QString::number(primaryRect.y());
   args << rect;

   qDebug() << "Arguments are: " << args;
   _process->start("x11vnc", args, QIODevice::ReadOnly);
}

void VncServer::stop()
{
   if (_timerId != 0) {
      killTimer(_timerId);
      _timerId = 0;
   }
   if (_process == nullptr)
      return;
   qDebug("Stopping old VNC server.");
   disconnect(_process, &QProcess::readyReadStandardOutput, this, &VncServer::onStdOut);
   disconnect(_process, &QProcess::readyReadStandardError, this, &VncServer::onStdErr);
   QProcess *process = _process;
   _process = nullptr;
   _port = 0;
   process->terminate();
   for (int i = 0; i < 10 && process->state() != QProcess::NotRunning; ++i)
      Sleeper::msleep(10);
   if (process->state() == QProcess::Running)
      process->kill();
   for (int i = 0; i < 10 && process->state() != QProcess::NotRunning; ++i)
      Sleeper::msleep(10);
   process->deleteLater();
}


/*
 * Overrides
 */


void VncServer::timerEvent(QTimerEvent * /* event */ )
{
   // Error timeout (3s), tell server that vnc setup failed
   this->stop();
   emit started(0, _ropass, _rwpass);
}


/*
 * Slots
 */


void VncServer::onStdOut()
{
   if (_process == nullptr) {
      qDebug("VncServer::onStdOut() called in bad state.");
      return;
   }
   QByteArray data(_process->readAllStandardOutput());
   qDebug() << "x11vnc: " << data;
   if (_port <= 0) {
      const int pos = data.indexOf("PORT=", 0);
      if (pos != -1) {
         _port = atoi(data.constData() + pos + 5);
         qDebug() << "Got VNC port " << _port << ", ro " << _ropass << ", rw " << _rwpass;
         emit started(_port, _ropass, _rwpass);
         // Kill error timer, but only if port seemed valid
         if (_timerId != 0 && _port > 0) {
            killTimer(_timerId);
            _timerId = 0;
         }
      }
   }
}

void VncServer::onStdErr()
{
   if (_process == nullptr) {
      qDebug("VncServer::onStdErr() called in bad state.");
      return;
   }
   _process->readAllStandardError(); // Throw away
}

void VncServer::onError(QProcess::ProcessError /* error */ )
{
   this->stop();
   emit started(0, _ropass, _rwpass);
}

void VncServer::onFinished(int /* exitCode */, QProcess::ExitStatus /* exitStatus */)
{
   this->stop();
   emit started(0, _ropass, _rwpass);
}