WTSQuerySessionInformation throws exception on null hServer

[nefarius]

Actual behavior

When passing null as hServer argument to WTSQuerySessionInformation it throws a System.ArgumentNullException despite the native WinApi docs stating that NULL (the macro WTS_CURRENT_SERVER_HANDLE expands to (HANDLE)NULL) is allowed to set the current machine as server.

Expected behavior

WTSQuerySessionInformation to succeed even with null as hServer.

Repro steps

1. NativeMethods.txt content:

WTSGetActiveConsoleSessionId
WTSQuerySessionInformation
WTSFreeMemory
WTS_INFO_CLASS

3. Any of your own code that should be shared?

    private static unsafe string GetUsername(int sessionId)
    {
        string username = SystemSessionUsername;
        if (PInvoke.WTSQuerySessionInformation(null, (uint)sessionId, WTS_INFO_CLASS.WTSUserName, out PWSTR buffer,
                out uint strLen) && strLen > 1)
        {
            username = new string(buffer.Value);
            PInvoke.WTSFreeMemory(buffer);
        }

        return username;
    }

Context

• CsWin32 version: 0.2.138-beta
• Win32Metadata version (if explicitly set by project): not explicitly set
• Target Framework: net7.0-windows10.0.17763.0
• LangVersion: latest

[AArnott]

This is a bug in the win32metadata, as it doesn't annotate the hServer parameter with [Optional]:

public unsafe static extern BOOL WTSQuerySessionInformationW([In] HANDLE hServer, [In] uint SessionId, [In] WTS_INFO_CLASS WTSInfoClass, [Out] PWSTR* ppBuffer, [Out] uint* pBytesReturned);

Contrast this with CreateFile, which does annotate its HANDLE hTemplateFile parameter with [Optional]:

public unsafe static extern HANDLE CreateFileW([In][Const] PWSTR lpFileName, [In] FILE_ACCESS_FLAGS dwDesiredAccess, [In] FILE_SHARE_MODE dwShareMode, [Optional][In] SECURITY_ATTRIBUTES* lpSecurityAttributes, [In] FILE_CREATION_DISPOSITION dwCreationDisposition, [In] FILE_FLAGS_AND_ATTRIBUTES dwFlagsAndAttributes, [Optional][In] HANDLE hTemplateFile);