[QUESTION] How to reboot the system when computer is locked?

[ComptonAlvaro]

I have a service that is hosted in a console application. I can send a request to this service to reboot the computer.

The computer has a normal user (no administrator), that log on when computer starts, and start this console application.

When I send the request to reboot the computer, it works if the user is log in, but is doesn't work when the session is locked. Normally the system lock the session when I connect through remote desktop, that when I close it, the computer passes to lock state, it doesn't keep the session opened.

I describe this to have an idea of the system, but in sumary, all works except when I send the request when the session is locked.

I have tried to shutdown the computer in two ways. The first one, is using the shutdown command, starting a new process. This is the code:

ProcessStartInfo miProcessStartInfo = new ProcessStartInfo();
miProcessStartInfo.Arguments = "/r /t 0 /soft";
miProcessStartInfo.FileName = "shutdown";
miProcessStartInfo.WindowStyle = ProcessWindowStyle.Hidden;
miProcessStartInfo.CreateNoWindow = true;

//int exitCode;

using (Process? miProceso = Process.Start(miProcessStartInfo))
{
    if (miProceso == null)
    {
        throw GetRpcException("");
    }
}

But I have read that this command it is not enough, that I should to use ExitWindowsEx. So I have tried this xample code:

public static class ExitWindowsExHelper
{
    [DllImport("user32.dll", SetLastError = true)]
    private static extern int ExitWindowsEx(ExitWindows uFlags, ShutdownReason dwReason);

    public static bool ExitWindows(ExitWindows exitWindows, ShutdownReason reason, bool ajustToken)
    {
        if (ajustToken && !TokenAdjuster.EnablePrivilege("SeShutdownPrivilege", true))
        {
            return false;
        }


        return ExitWindowsEx(exitWindows, reason) != 0;
    }
}







[Flags]
public enum ExitWindows : uint
{
    // ONE of the following:
    LogOff = 0x00,
    ShutDown = 0x01,
    Reboot = 0x02,
    PowerOff = 0x08,
    RestartApps = 0x40,
    // plus AT MOST ONE of the following two:
    Force = 0x04, //esto hace que cierre sesión, no que se reinicie.
    ForceIfHung = 0x10,
    ForceReboot = 0x60,
}





[Flags]
public enum ShutdownReason : uint
{
    None = 0,

    MajorApplication = 0x00040000,
    MajorHardware = 0x00010000,
    MajorLegacyApi = 0x00070000,
    MajorOperatingSystem = 0x00020000,
    MajorOther = 0x00000000,
    MajorPower = 0x00060000,
    MajorSoftware = 0x00030000,
    MajorSystem = 0x00050000,

    MinorBlueScreen = 0x0000000F,
    MinorCordUnplugged = 0x0000000b,
    MinorDisk = 0x00000007,
    MinorEnvironment = 0x0000000c,
    MinorHardwareDriver = 0x0000000d,
    MinorHotfix = 0x00000011,
    MinorHung = 0x00000005,
    MinorInstallation = 0x00000002,
    MinorMaintenance = 0x00000001,
    MinorMMC = 0x00000019,
    MinorNetworkConnectivity = 0x00000014,
    MinorNetworkCard = 0x00000009,
    MinorOther = 0x00000000,
    MinorOtherDriver = 0x0000000e,
    MinorPowerSupply = 0x0000000a,
    MinorProcessor = 0x00000008,
    MinorReconfig = 0x00000004,
    MinorSecurity = 0x00000013,
    MinorSecurityFix = 0x00000012,
    MinorSecurityFixUninstall = 0x00000018,
    MinorServicePack = 0x00000010,
    MinorServicePackUninstall = 0x00000016,
    MinorTermSrv = 0x00000020,
    MinorUnstable = 0x00000006,
    MinorUpgrade = 0x00000003,
    MinorWMI = 0x00000015,

    FlagUserDefined = 0x40000000,
    FlagPlanned = 0x80000000
}





public sealed class TokenAdjuster
{
    // PInvoke stuff required to set/enable security privileges
    private const int SE_PRIVILEGE_ENABLED = 0x00000002;
    private const int TOKEN_ADJUST_PRIVILEGES = 0X00000020;
    private const int TOKEN_QUERY = 0X00000008;
    private const int TOKEN_ALL_ACCESS = 0X001f01ff;
    private const int PROCESS_QUERY_INFORMATION = 0X00000400;

    [DllImport("advapi32", SetLastError = true), SuppressUnmanagedCodeSecurity]
    private static extern int OpenProcessToken(
        IntPtr ProcessHandle, // handle to process
        int DesiredAccess, // desired access to process
        ref IntPtr TokenHandle // handle to open access token
        );

    [DllImport("kernel32", SetLastError = true),
     SuppressUnmanagedCodeSecurity]
    private static extern bool CloseHandle(IntPtr handle);

    [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern int AdjustTokenPrivileges(
        IntPtr TokenHandle,
        int DisableAllPrivileges,
        IntPtr NewState,
        int BufferLength,
        IntPtr PreviousState,
        ref int ReturnLength);

    [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool LookupPrivilegeValue(
        string lpSystemName,
        string lpName,
        ref LUID lpLuid);

    public static bool EnablePrivilege(string lpszPrivilege, bool bEnablePrivilege)
    {
        bool retval = false;
        int ltkpOld = 0;
        IntPtr hToken = IntPtr.Zero;
        TOKEN_PRIVILEGES tkp = new TOKEN_PRIVILEGES();
        tkp.Privileges = new int[3];
        TOKEN_PRIVILEGES tkpOld = new TOKEN_PRIVILEGES();
        tkpOld.Privileges = new int[3];
        LUID tLUID = new LUID();
        tkp.PrivilegeCount = 1;
        if (bEnablePrivilege)
            tkp.Privileges[2] = SE_PRIVILEGE_ENABLED;
        else
            tkp.Privileges[2] = 0;
        if (LookupPrivilegeValue(null, lpszPrivilege, ref tLUID))
        {
            Process proc = Process.GetCurrentProcess();
            if (proc.Handle != IntPtr.Zero)
            {
                if (OpenProcessToken(proc.Handle, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY,
                    ref hToken) != 0)
                {
                    tkp.PrivilegeCount = 1;
                    tkp.Privileges[2] = SE_PRIVILEGE_ENABLED;
                    tkp.Privileges[1] = tLUID.HighPart;
                    tkp.Privileges[0] = tLUID.LowPart;
                    const int bufLength = 256;
                    IntPtr tu = Marshal.AllocHGlobal(bufLength);
                    Marshal.StructureToPtr(tkp, tu, true);
                    if (AdjustTokenPrivileges(hToken, 0, tu, bufLength, IntPtr.Zero, ref ltkpOld) != 0)
                    {
                        // successful AdjustTokenPrivileges doesn't mean privilege could be changed
                        if (Marshal.GetLastWin32Error() == 0)
                        {
                            retval = true; // Token changed
                        }
                    }
                    TOKEN_PRIVILEGES tokp = (TOKEN_PRIVILEGES)Marshal.PtrToStructure(tu, typeof(TOKEN_PRIVILEGES));
                    Marshal.FreeHGlobal(tu);
                }
            }
        }
        if (hToken != IntPtr.Zero)
        {
            CloseHandle(hToken);
        }
        return retval;
    }

    [StructLayout(LayoutKind.Sequential)]
    internal struct LUID
    {
        internal int LowPart;
        internal int HighPart;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct LUID_AND_ATTRIBUTES
    {
        private LUID Luid;
        private int Attributes;
    }

    [StructLayout(LayoutKind.Sequential)]
    internal struct TOKEN_PRIVILEGES
    {
        internal int PrivilegeCount;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
        internal int[] Privileges;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct _PRIVILEGE_SET
    {
        private int PrivilegeCount;
        private int Control;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)] // ANYSIZE_ARRAY = 1
        private LUID_AND_ATTRIBUTES[] Privileges;
    }
}

And I call in this way:
ExitWindowsExHelper.ExitWindows(ExitWindows.ForceReboot, ShutdownReason.MajorSystem, true);

But it doesn't work too. I have the same behavior, I can reboot when the session is open but I can't when it is locked.

So i summary, I would like to know if there is some way to reboot the computer when the computer is locked, in the log in screen.

Thanks.

[Clockwork-Muse]

... why are you writing an application to do this?

There are built-in commands to remotely restart Windows. Besides that, assuming you're running a reasonable management package you should be able to reboot machines via its interface as well.