C#でコンピュータの再起動、シャットダウンとログアウトを制御する

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace chkipsrv
{
public class Shudown
  {
  [StructLayout(LayoutKind.Sequential, Pack = 1)]
internal struct TokPriv1Luid
  {
public int Count;
public long Luid;
public int Attr;
  }

  [DllImport("kernel32.dll", ExactSpelling = true)]
internal static extern IntPtr GetCurrentProcess();

  [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok);

  [DllImport("advapi32.dll", SetLastError = true)]
internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

  [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall,
ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

  [DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
internal static extern bool ExitWindowsEx(int DoFlag, int rea);

internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
internal const int TOKEN_QUERY = 0x00000008;
internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;
internal const string SE_SHUTDOWN_NAME = "SeShutdownPrivilege";
internal const int EWX_LOGOFF = 0x00000000;
internal const int EWX_SHUTDOWN = 0x00000001;
internal const int EWX_REBOOT = 0x00000002;
internal const int EWX_FORCE = 0x00000004;
internal const int EWX_POWEROFF = 0x00000008;
internal const int EWX_FORCEIFHUNG = 0x00000010;

private static void DoExitWin(int DoFlag)
  {
bool ok;
  TokPriv1Luid tp;
  IntPtr hproc = GetCurrentProcess();
  IntPtr htok = IntPtr.Zero;
  ok = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
  tp.Count = 1;
  tp.Luid = 0;
  tp.Attr = SE_PRIVILEGE_ENABLED;
  ok = LookupPrivilegeValue(null, SE_SHUTDOWN_NAME, ref tp.Luid);
  ok = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
  ok = ExitWindowsEx(DoFlag, 0);
  }

public static void Reboot()
  {
  DoExitWin(EWX_FORCE | EWX_REBOOT);
  }

public static void PowerOff()
  {
  DoExitWin(EWX_FORCE | EWX_POWEROFF);
  }

public static void LogOff()
  {
  DoExitWin(EWX_FORCE | EWX_LOGOFF);
  }
  }
}