Re: Environment / WindowsIdentity

From:

colbertz@online.microsoft.com (Colbert Zhou [MSFT])

Newsgroups:

microsoft.public.dotnet.framework

Date:

Fri, 25 Sep 2009 06:59:01 GMT

Message-ID:

<Errux2aPKHA.5908@TK2MSFTNGHUB02.phx.gbl>

Hello All,

You can see the WindowsIdentity.GetCurrent().Name retrieves the name from
this.User
--------------------Codes--------------
this.m_name = (this.User.Translate(typeof(NTAccount)) as
NTAccount).ToString();
--------------------------------------------

If you look into this.User property implementation using Reflector, you can
find,
--------------------Codes--------------
[ComVisible(false)]
public SecurityIdentifier User
{
    get
    {
        if (this.m_safeTokenHandle.IsInvalid)
        {
            return null;
        }
        if (this.m_user == null)
        {
            uint dwLength = 0;
            SafeLocalAllocHandle handle =
GetTokenInformation(this.m_safeTokenHandle,
TokenInformationClass.TokenUser, out dwLength);
            this.m_user = new
SecurityIdentifier(Marshal.ReadIntPtr(handle.DangerousGetHandle()), true);
            handle.Dispose();
        }
        return this.m_user;
    }
}

private static SafeLocalAllocHandle GetTokenInformation(SafeTokenHandle
tokenHandle, TokenInformationClass tokenInformationClass, out uint dwLength)
{
    SafeLocalAllocHandle invalidHandle = SafeLocalAllocHandle.InvalidHandle;
    dwLength = (uint) Marshal.SizeOf(typeof(uint));
    bool flag = Win32Native.GetTokenInformation(tokenHandle, (uint)
tokenInformationClass, invalidHandle, 0, out dwLength);
    int errorCode = Marshal.GetLastWin32Error();
    int num2 = errorCode;
    if (num2 == 6)
    {
        throw new
ArgumentException(Environment.GetResourceString("Argument_InvalidImpersonati
onToken"));
    }
    if ((num2 != 0x18) && (num2 != 0x7a))
    {
        throw new SecurityException(Win32Native.GetMessage(errorCode));
    }
    IntPtr sizetdwBytes = new IntPtr((long) ((ulong) dwLength));
    invalidHandle = Win32Native.LocalAlloc(0, sizetdwBytes);
    if ((invalidHandle == null) || invalidHandle.IsInvalid)
    {
        throw new OutOfMemoryException();
    }
    if (!Win32Native.GetTokenInformation(tokenHandle, (uint)
tokenInformationClass, invalidHandle, dwLength, out dwLength))
    {
        throw new
SecurityException(Win32Native.GetMessage(Marshal.GetLastWin32Error()));
    }
    return invalidHandle;
}

--------------------------------------------
We can see that it eventually calls into Win32Native.GetTokenInformation
API to retrieve the current user name information.
http://msdn.microsoft.com/en-us/library/aa446671(VS.85).aspx

Although from two different APIs, I think their returned value should be
same exception one include domain information.

Best regards,
Ji Zhou
Microsoft Managed Newsgroup Support Team