QProcess start netsh command with quotes and spaces in parameter argument question.

teungri

Hello,
I want to set my network interface adapter on windows to static/dhcp with the netsh command via QProcess.
The command should be:
netsh interface ipv4 set address "USB-Ethernet Adapter" dhcp
This command is working when I execute it from the windows command line. However I want to execute this
command in a Qt application via QProcess.

I read already various threads about this issue but I never reached a successful result. see
http://doc.qt.io/qt-5/qprocess.html#start-3
From this documentation I should use """"USB-Ethernet Adapter"""",
triple " to expand to ", the 4th one because a space in the parameter.
Here is my different code I use to set dhcp:

    //-----------------------------------------------------------------------------------------------------------
    void setDhcp()
    {
        QStringList args;
        QProcess proc;
        args.clear();
        args << "interface" << "ipv4" << "set" << "address";
         //    args << "\"" + nwAdapter + "\"";
        args << "\"\"\"\"" + nwAdapter + "\"\"\"\"";
        args << "dhcp";

     //    proc.start( "netsh", args );
    //    proc.waitForFinished();

    int exitCode = 0;
    //    exitCode = QProcess::execute("netsh", args );

    QString cmd = "netsh " + args.join(" ");
    qCDebug(DBG) << "cmd=" << cmd << "exitCode=" << exitCode;
    //    exitCode = QProcess::execute( cmd );
    proc.start( cmd );
    proc.waitForFinished();
}
//-----------------------------------------------------------------------------------------------------------

The result of printing cmd is:

cmd= "netsh interface ipv4 set address """"USB-Ethernet Adapter"""" dhcp" exitCode= 0

Is there anybody who has a clue to this problem?

currently i stick the the "system(cmd)';" solution which is working, but than annoying
windows popups occur.

Thanks in advance for your info.
Kind regards,

teungri

Hello,
Since no one is replying, there is possibly no qt solution. FYI, I solved my problem with old school
windows api, see code below (the netshName contains spaces):

cmd = QString("netsh interface ipv4 set address name=\"%1\" static").  arg(this->networkAdapter()->netshName());
cmd += " 169.254.1.1 255.255.255.0 169.254.1.1 1";
ExecuteNetsh( cmd.toStdString().c_str() );

static void ExecuteNetsh(const char* strCmd )
{
    char strPath[1024];
    STARTUPINFOA startinfo;
    PROCESS_INFORMATION process;
    DWORD dwRes;

    //fill start-info
    GetStartupInfoA(&startinfo);
    startinfo.cb = sizeof (startinfo);
    startinfo.dwFlags = STARTF_USESHOWWINDOW;
    startinfo.wShowWindow = SW_HIDE;

	//get netsh-path
	GetSystemDirectoryA(strPath, 1024);
	strcat( strPath, "\\netsh.exe" );

    //start netsh
    if (!CreateProcessA(strPath, (LPSTR)strCmd, NULL, NULL,
                        FALSE, 0, NULL, NULL, &startinfo, &process))
    {
        qCDebug(DBG) << QString("Error while trying to execute %1 %2").arg(strPath).arg(strCmd);
        return;
    }

	//wait until finished
	WaitForSingleObject(process.hProcess, INFINITE);

	//check exit-code
	GetExitCodeProcess(process.hProcess, &dwRes);
	if(dwRes != 0) qCCritical(DBG) << QString( "GetExitCodeProcess error %1\n\tcmd=%2").
            arg( GetLastError() ).
            arg( strCmd );

	//close handles
	CloseHandle(process.hThread);
	CloseHandle(process.hProcess);
}

Kind regards,
Teun Grinwis

Chris Kawa

Here's an example that will print info on all available interfaces:

QString command("netsh interface ipv4 show addresses \"%1\"");

auto infs = QNetworkInterface::allInterfaces();
for(auto inf : infs)
{
    QProcess proc;
    proc.start(command.arg(inf.humanReadableName()));
    proc.waitForFinished();
    qDebug() << proc.readAll();
}

You can adjust it to fit your needs.