Platform Invoke of TakeCmd.dll

[Joe Caverly]

I have the following function defined in my PowerShell profile;

function tcc
{
  & "c:\program files\jpsoft\tcmd25\tcc.exe" /I /Q /C $args

}

This allows me to call Take Command internal functions and commands from PowerShell.

Loading tcc.exe this way is fast, but I was looking for a way to make it faster.

The method I am testing now is using Platform Invoke to call the internal functions and commands from the unmanaged TakeCmd.dll file.

I am using the TakeCmd.h file from the plugin SDK as a guide.

First, I have created a TakeCmd.ps1 file containing C# code to define a command and a function that exist in the unmanaged TakeCmd.dll file;

Add-Type -TypeDefinition @'
using System;
using System.Runtime.InteropServices;

public static class TakeCmd
{
[DllImport("takecmd.dll", CharSet = CharSet.Auto)]
public static extern void honk();

[DllImport("takecmd.dll", CharSet = CharSet.Auto)]
public static extern int GetExeType( string pszFilename );
}
'@

I load this in PowerShell as;

PS E:\Utils> .\takecmd.ps1

I can see the class members;

PS E:\Utils> [takecmd] | get-member -static


   TypeName: TakeCmd

Name            MemberType Definition
----            ---------- ----------
Equals          Method     static bool Equals(System.Object objA, System.Object objB)
GetExeType      Method     static int GetExeType(string pszFilename)
honk            Method     static void honk()
ReferenceEquals Method     static bool ReferenceEquals(System.Object objA, System.Object objB)

I then change to the folder where the unmanaged TakeCmd.dll is located;

PS E:\Utils> [environment]::CurrentDirectory = 'c:\program files\jpsoft\tcmd25'

...and I can beep (honk);

PS E:\Utils> [TakeCmd]::honk()

When I invoke the GetExeType function;

PS E:\Utils> [TakeCmd]::GetExeType(".\WMIGen.exe")
-2
PS E:\Utils> [TakeCmd]::GetExeType("WMIGen.exe")
-2

...the return value is not correct.

Here is GetExeType from TakeCmd.h;

INT WINAPI GetExeType( LPCTSTR pszFilename );
/*
    Returns an integer specifying the type of executable:
    

        0    // Error, or not an EXE file
        1    // Just plain old MS-DOS
        2    // DOS app with a PIF file
        3    // Windows 3.x
        4    // Windows 3.x VxD
        5    // OS/2 2.x
        6    // Windows NT, 2000, XP, or 2003 GUI
        7    // Windows NT, 2000, XP, or 2003 console mode
        8    // Windows NT, 2000, XP, or 2003 Posix
        9    // Windows x64 GUI
        10    // Windows x64 console
        11    // EFI
        12    // EFI boot driver
        13    // EFI runtime driver
        14    // EFI ROM
        15    // XBox
        16    // Windows boot application
*/

For the example function I am testing, GetExeType, I would appreciate input from the PowerShell folks on how to properly define the DllImport, and how to properly get the return value from this example.

Joe

 

[vefatica]

What is the "unmanaged takecmd.dll file"?

I wouldn't be surprised if little worked without TCC performing whatever initializations are needed.

Does Powershell know that strings are Unicode?

 

[Joe Caverly]

C++ is used to create TakeCmd.dll, which means that the .dll is unmanaged. This can be verified as follows;

c:\program files\jpsoft\tcmd25>corflags.exe takecmd.dll
Microsoft (R) .NET Framework CorFlags Conversion Tool.  Version  4.8.3928.0
Copyright (c) Microsoft Corporation.  All rights reserved.

corflags : error CF008 : The specified file does not have a valid managed header

I used C# to create jlcNETUtils.dll, which means that the .dll is managed. This can be verified as follows;

e:\utils>corflags.exe jlcNETUtils.dll
Microsoft (R) .NET Framework CorFlags Conversion Tool.  Version  4.8.3928.0
Copyright (c) Microsoft Corporation.  All rights reserved.

Version   : v4.0.30319
CLR Header: 2.5
PE        : PE32
CorFlags  : 0x1
ILONLY    : 1
32BITREQ  : 0
32BITPREF : 0
Signed    : 0

In the .NET PowerShell environment, the DllImport Attribute can be set to recognize Unicode.

So, in my previous post, the DllImport would become;

Add-Type -TypeDefinition @'
using System;
using System.Runtime.InteropServices;

public static class TakeCmd
{
[DllImport("takecmd.dll", CharSet = CharSet.Unicode)]
public static extern void honk();

[DllImport("takecmd.dll", CharSet = CharSet.Unicode)]
public static extern int GetExeType( string pszFilename );
}
'@

A good majority of the unmanaged Windows API has been translated to Platform Invoke format, so as to be called from managed code.

Joe