pinvoke.net: Edit: advapi32.GetTokenInformation

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Summary: Retrieves a specified type of information about an access token

!!!!C# Signature:
 [DllImport("advapi32.dll", SetLastError=true)]
 static extern bool GetTokenInformation(
 	IntPtr TokenHandle,
 	TOKEN_INFORMATION_CLASS TokenInformationClass,
 	IntPtr TokenInformation,
 	uint TokenInformationLength,
 	out uint ReturnLength);

!!!!VB.NET Definition:
    Public Declare Function GetTokenInformation Lib "advapi32.dll" ( _
    ByVal TokenHandle As IntPtr, ByVal TokenInformationClass As TOKEN_INFORMATION_CLASS, _
    ByVal TokenInformation As IntPtr, ByVal TokenInformationLength As System.UInt32, _
    ByRef ReturnLength As System.UInt32) As Boolean

!!!!User-Defined Types:
[TOKEN_INFORMATION_CLASS]

!!!!Notes:
Call once with zero for the third and fourth parameters to obtain the required size, then allocate the buffer and call again supplying these parameters.

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:
// Prints out sid of current user

using System;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.Text;
namespace test
{
	class clsLookupAccountName
	{

enum TOKEN_INFORMATION_CLASS
		{
			TokenUser = 1,
			TokenGroups,
			TokenPrivileges,
			TokenOwner,
			TokenPrimaryGroup,
			TokenDefaultDacl,
			TokenSource,
			TokenType,
			TokenImpersonationLevel,
			TokenStatistics,
			TokenRestrictedSids,
			TokenSessionId,
			TokenGroupsAndPrivileges,
			TokenSessionReference,
			TokenSandBoxInert,
			TokenAuditPolicy,
			TokenOrigin
		}

public struct TOKEN_USER 
		{ 
			public SID_AND_ATTRIBUTES User ; 
		}

[StructLayout(LayoutKind.Sequential)]
		public struct SID_AND_ATTRIBUTES 
		{

public IntPtr Sid ; 
			public int Attributes ; 
		} 
		
		// Using IntPtr for pSID insted of Byte[]
		[DllImport("advapi32", CharSet=CharSet.Auto, SetLastError=true)]
		static extern bool ConvertSidToStringSid(
			IntPtr pSID, 
			out IntPtr ptrSid);

[DllImport("kernel32.dll")]
		static extern IntPtr LocalFree(IntPtr hMem);

[DllImport("advapi32.dll", SetLastError=true)]
		static extern bool GetTokenInformation(
			IntPtr TokenHandle,
			TOKEN_INFORMATION_CLASS TokenInformationClass,
			IntPtr TokenInformation,
			int TokenInformationLength,
			out int ReturnLength);

[STAThread]
		static void Main(string[] args)
		{
			int TokenInfLength = 0 ; 
			bool Result ;

// first call gets lenght of TokenInformation
			Result = GetTokenInformation( WindowsIdentity.GetCurrent().Token , TOKEN_INFORMATION_CLASS.TokenUser , IntPtr.Zero , TokenInfLength , out TokenInfLength );

IntPtr TokenInformation = Marshal.AllocHGlobal( TokenInfLength ) ; 
			
			Result = GetTokenInformation( WindowsIdentity.GetCurrent().Token  , TOKEN_INFORMATION_CLASS.TokenUser , TokenInformation , TokenInfLength , out TokenInfLength ) ; 
			
			if( Result ) 
			{
				TOKEN_USER TokenUser = ( TOKEN_USER )Marshal.PtrToStructure( TokenInformation , typeof( TOKEN_USER ) ) ; 
				
				IntPtr pstr = IntPtr.Zero; 
				Boolean ok = ConvertSidToStringSid( TokenUser.User.Sid  , out pstr ); 
				string sidstr = Marshal.PtrToStringAuto( pstr ); 
				LocalFree(pstr);
				Console.WriteLine(@"Found sid {0}",sidstr);
			}

Marshal.FreeHGlobal( TokenInformation );

Console.ReadLine();
		}
	}

}

There's a sample based on this at http://stackoverflow.com/questions/2146153/how-to-get-the-logon-sid-in-c/2146418#2146418 that gets the LogonSID instead.

!!!!Alternative Managed API:
Do you know one?  Please contribute it!

Documentation: MSDN http://msdn.microsoft.com/en-us/library/aa446671%28VS.85%29.aspx