QProcess start for mstsc (Remote Desktop) generates finished() signal immediately

m4kas

Updated my code in next way:

void MainWindow::on_tbl_machines_doubleClicked(const QModelIndex &index)
{
    QString machine_address = ui->tbl_machines->model()->index(index.row(), 1).data().toString();
    QString machine_user = ui->tbl_machines->model()->index(index.row(), 4).data().toString();
    QString machine_password = ui->tbl_machines->model()->index(index.row(), 5).data().toString();

    // cmdkey /generic:<servername> /user:<username> /pass:<password>
    QStringList arg_list= QStringList() << QString("/generic:%1").arg(machine_address) << QString("/user:%1").arg(machine_user) << QString("/pass:%1").arg(machine_password);
    QProcess::execute("cmdkey", arg_list);

    QProcess *process = new QProcess();
    rdp_processes_list.append(process);
    connect(process, SIGNAL(finished(int, QProcess::ExitStatus)), this, SLOT(rdp_process_finished(int, QProcess::ExitStatus)));
    connect(process, SIGNAL(error(QProcess::ProcessError)), this, SLOT(rdp_process_error(QProcess::ProcessError)));
    connect(process, SIGNAL(started()), this, SLOT(rdp_process_started()));
    connect(process, SIGNAL(stateChanged(QProcess::ProcessState)), this, SLOT(rdp_process_state_changed(QProcess::ProcessState)));
    // start cmd and start mstsc app with /wait key to wait till RDP session is closed.
    process->start("cmd", QStringList() << "/c" << "start" << "/wait" << "mstsc" << "/v" << machine_address);
    // returns true if process started successfully
    process->waitForStarted(-1);
    process->waitForReadyRead(-1);
    qDebug() << "readAllStandardError:" << process->readAllStandardError();
    qDebug() << "readAllStandardOutput:" << process->readAllStandardOutput();
}

/* SLOTS */

void MainWindow::rdp_process_started()
{
    qDebug() << "started slot: Process started";
}

void MainWindow::rdp_process_state_changed(QProcess::ProcessState newState)
{
    qDebug() << "stateChanged slot: Process state changed. New state: " << newState;
}

void MainWindow::rdp_process_finished(int exitCode, QProcess::ExitStatus exitStatus)
{
    qDebug() << "finished slot: Exit code: " << exitCode << " Exit status: " << exitStatus;
}

void MainWindow::rdp_process_error(QProcess::ProcessError error)
{
    qDebug() << "error slot: Process error:  " << error;
}

And got next messages from qDebug():

CMDKEY: Credential added successfully.
stateChanged slot: Process state changed. New state:  QProcess::Starting
stateChanged slot: Process state changed. New state:  QProcess::Running
started slot: Process started
stateChanged slot: Process state changed. New state:  QProcess::NotRunning
finished slot: Exit code:  0  Exit status:  QProcess::NormalExit
readAllStandardError: ""
readAllStandardOutput: ""

So, it does not look mstsc want to say something to me...

Christian Ehrlicher

int main(int argc, char* argv[])
{
    QApplication a(argc, argv);

    QProcess* proc = new QProcess;
    QObject::connect(proc, &QProcess::started,
        []() { qDebug() << "started";  });
    QObject::connect(proc, &QProcess::stateChanged,
        [](QProcess::ProcessState s) { qDebug() << "stateChanged:" << s;  });
    QObject::connect(proc, qOverload<int,QProcess::ExitStatus>(&QProcess::finished),
        [](int c, QProcess::ExitStatus s) { 
        qDebug() << "finished:" << c << s;
        QCoreApplication::quit(); 
    });
    proc->start("mstsc", { "/v:127.0.0.1" });
    return a.exec();
}

-->
stateChanged: QProcess::Running
started
// connect dialog is shown, I kill it
stateChanged: QProcess::NotRunning
finished: 0 QProcess::NormalExit

Works perfectly fine for me. Still don't understand why everyone wants to use cmd /c to run a simple windows executable...

m4kas

@Christian-Ehrlicher
My log when using your code:

stateChanged: QProcess::Starting
stateChanged: QProcess::Running
started
stateChanged: QProcess::NotRunning
finished: 0 QProcess::NormalExit
// RDP session is still in progress

Update: when using your code, but not with loopback, but with real remote machine IP . Using with loopback gives error about "could not connect to another console session".

Christian Ehrlicher

I don't know what exactly mstsc is doing but maybe it's detaching the rdp connection internally so the mstsc process is not running when the rdp session is open. Take a look into your running taskmanager/processes when you have an open rdp connection if the mstsc process which you're using for connecting is still there. I would say it's not the case.

m4kas

@Christian-Ehrlicher
Yes, I can see mstsc.exe in active processes list after QT reported finished() for that process.

Christian Ehrlicher

@m4kas said in QProcess start for mstsc (Remote Desktop) generates finished() signal immediately:

I can see mstsc.exe in active processes list after

And is it exactly this process which was started from Qt? Check the process id.

m4kas

@Christian-Ehrlicher
Good catch!
PIDs really differs. Now I will try to understand how track the process, that is being started by mstsc I am starting...

mrjj

@m4kas
Hi
I think you are going to need to use the APIs
https://docs.microsoft.com/en-us/windows/win32/termserv/terminal-services-administration

m4kas

As mentioned on microsoft forum post, most likely when building 32-bit app (which I was doing), it makes mstsc call of 32-bit version mstsc, which calls the correct 64-bit version and closes original process that was called from QT app.
Switched my QT project to build 64 bit application and it fixed my problem - now finished() signal is being emitted exactly after RDP session finished.
@Christian-Ehrlicher @JonB @mrjj thanks for your inputs.
Issue is solved.

mrjj

@m4kas
Good digging!