通过其SID检查LocalGroup是否存在

Question

我想通过它的SID Remote Desktop Users检查LocalGroup S-1-5-32-555是否存在，然后运行一些代码来获取它的名称。我要使用SID，因为该组的名称在不同的语言中是不同的。 我当前正在使用此代码，但是当系统没有SidTranslator LocalGroup时，会在Remote Desktop Users上获得意外的句柄。

PS：extractName是将BUILTIN\GROUPNAME转换为GROUPNAME的正则表达式。

SecurityIdentifier rduSID = new 
SecurityIdentifier(WellKnownSidType.BuiltinRemoteDesktopUsersSid, null);
string rduName = extractName(MBC.Security.SidTranslator.GetName(rduSID.ToString()));

SidTranslator.cs（MBC.Security）：

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Text;

namespace MBC.Security
{
/// <summary>
/// This class provides two metods to convert object name (user, group) to SID and vice-versa.
/// </summary>
public class SidTranslator
{

    [DllImport( "advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
    private static extern bool LookupAccountSid([In,MarshalAs(UnmanagedType.LPTStr)] string systemName, IntPtr sid, [Out,MarshalAs(UnmanagedType.LPTStr)] StringBuilder name, ref int cbName, StringBuilder referencedDomainName, ref int cbReferencedDomainName, out int use );

    [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
    public static extern bool LookupAccountName([In,MarshalAs(UnmanagedType.LPTStr)] string systemName, [In,MarshalAs(UnmanagedType.LPTStr)] string accountName, IntPtr sid, ref int cbSid, StringBuilder referencedDomainName, ref int cbReferencedDomainName, out int use);

    [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
    internal static extern bool ConvertSidToStringSid(IntPtr sid, [In,Out,MarshalAs(UnmanagedType.LPTStr)] ref string pStringSid);

    [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
    internal static extern bool ConvertStringSidToSid([In, MarshalAs(UnmanagedType.LPTStr)] string pStringSid, ref IntPtr sid);

    /// <summary>
    /// The method converts object name (user, group) into SID string.
    /// </summary>
    /// <param name="name">Object name in form domain\object_name.</param>
    /// <returns>SID string.</returns>
    public static string GetSid(string name)
    {
        IntPtr _sid = IntPtr.Zero;  //pointer to binary form of SID string.
        int _sidLength = 0;         //size of SID buffer.
        int _domainLength = 0;      //size of domain name buffer.
        int _use;                   //type of object.
        StringBuilder _domain = new StringBuilder();    //stringBuilder for domain name.
        int _error = 0;             
        string _sidString = "";

        //first call of the function only returns the sizes of buffers (SDI, domain name)
        LookupAccountName(null, name, _sid, ref _sidLength, _domain, ref _domainLength, out _use);
        _error = Marshal.GetLastWin32Error();

        if (_error != 122) //error 122 (The data area passed to a system call is too small) - normal behaviour.
        {
            throw(new Exception(new Win32Exception(_error).Message));
        }
        else
        {
            _domain = new StringBuilder(_domainLength); //allocates memory for domain name
            _sid = Marshal.AllocHGlobal(_sidLength);    //allocates memory for SID
            bool _rc = LookupAccountName(null, name, _sid, ref _sidLength, _domain, ref _domainLength, out _use);

            if (_rc == false)
            {
                _error = Marshal.GetLastWin32Error();
                Marshal.FreeHGlobal(_sid);
                throw(new Exception(new Win32Exception(_error).Message));
            }
            else
            {
                // converts binary SID into string
                _rc = ConvertSidToStringSid(_sid, ref _sidString);

                if (_rc == false)
                {
                    _error = Marshal.GetLastWin32Error();
                    Marshal.FreeHGlobal(_sid);
                    throw(new Exception(new Win32Exception(_error).Message));
                }
                else
                {
                    Marshal.FreeHGlobal(_sid);
                    return _sidString;
                }
            }
        }

    }

    /// <summary>
    /// The method converts SID string (user, group) into object name.
    /// </summary>
    /// <param name="name">SID string.</param>
    /// <returns>Object name in form domain\object_name.</returns>
    public static string GetName(string sid)
    {
        IntPtr _sid = IntPtr.Zero;  //pointer to binary form of SID string.
        int _nameLength = 0;        //size of object name buffer
        int _domainLength = 0;      //size of domain name buffer
        int _use;                   //type of object
        StringBuilder _domain = new StringBuilder();    //domain name variable
        int _error = 0;
        StringBuilder _name = new StringBuilder();      //object name variable

        bool _rc0 = ConvertStringSidToSid(sid, ref _sid);   //converts SID string into the binary form

        if (_rc0 == false)
        {
            _error = Marshal.GetLastWin32Error();
            Marshal.FreeHGlobal(_sid);
            throw(new Exception(new Win32Exception(_error).Message));
        }

        //first call of method returns the size of domain name and object name buffers
        bool _rc = LookupAccountSid(null, _sid, _name, ref _nameLength, _domain, ref _domainLength, out _use);
        _domain = new StringBuilder(_domainLength); //allocates memory for domain name
        _name = new StringBuilder(_nameLength);     //allocates memory for object name
        _rc = LookupAccountSid(null, _sid,  _name, ref _nameLength, _domain, ref _domainLength, out _use);

        if (_rc == false)
        {
            _error = Marshal.GetLastWin32Error();
            Marshal.FreeHGlobal(_sid);
            throw(new Exception(new Win32Exception(_error).Message));
        }
        else
        {
            Marshal.FreeHGlobal(_sid);
            return _domain.ToString() + "\\" + _name.ToString();
        }
    }
}
}`