Q176695: PRB: ExitWindowsEx API Does Not Reboot Windows NT

Article: Q176695
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0,6.0
Operating System(s): 
Keyword(s): kbVBp400 kbVBp500 kbVBp600 kbGrpDSVB kb32bitOnly
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

When you use the ExitWindowsEx API to reboot the system under Windows NT and
Windows 2000, the machine does not reboot.

CAUSE
=====

In order to programmatically reboot a Windows NT or Windows 2000 system, the
process requires the SE_SHUTDOWN_NAME privilege. By default, Visual Basic
applications do not have this privilege and therefore will not reboot the
machine.

RESOLUTION
==========

In order to get ExitWindowsEx API to reboot the system under Windows NT or
Windows 2000, the SE_SHUTDOWN_NAME privilege must be set. The following steps
describe how to get the ExitWindowsEx API to work under Windows NT and Windows
2000.

Step By Step Example
--------------------

1. Create a new standard EXE in Visual Basic. Form1 is created by default.

2. View the code for Form1. In the Declarations section, add the following code:

        Private Type LUID
           UsedPart As Long
           IgnoredForNowHigh32BitPart As Long
        End Type

        Private Type TOKEN_PRIVILEGES
          PrivilegeCount As Long
          TheLuid As LUID
          Attributes As Long
        End Type

        Private Const EWX_SHUTDOWN As Long = 1
        Private Const EWX_FORCE As Long = 4
        Private Const EWX_REBOOT = 2

        Private Declare Function ExitWindowsEx Lib "user32" (ByVal _
             dwOptions As Long, ByVal dwReserved As Long) As Long

        Private Declare Function GetCurrentProcess Lib "kernel32" () As Long
        Private Declare Function OpenProcessToken Lib "advapi32" (ByVal _
           ProcessHandle As Long, _
           ByVal DesiredAccess As Long, TokenHandle As Long) As Long
        Private Declare Function LookupPrivilegeValue Lib "advapi32" _
           Alias "LookupPrivilegeValueA" _
           (ByVal lpSystemName As String, ByVal lpName As String, lpLuid _
           As LUID) As Long
        Private Declare Function AdjustTokenPrivileges Lib "advapi32" _
           (ByVal TokenHandle As Long, _
           ByVal DisableAllPrivileges As Long, NewState As TOKEN_PRIVILEGES _
           , ByVal BufferLength As Long, _
        PreviousState As TOKEN_PRIVILEGES, ReturnLength As Long) As Long

3. Add a procedure called AdjustToken with the following code:

        Private Sub AdjustToken()
           Const TOKEN_ADJUST_PRIVILEGES = &H20
           Const TOKEN_QUERY = &H8
           Const SE_PRIVILEGE_ENABLED = &H2
           Dim hdlProcessHandle As Long
           Dim hdlTokenHandle As Long
           Dim tmpLuid As LUID
           Dim tkp As TOKEN_PRIVILEGES
           Dim tkpNewButIgnored As TOKEN_PRIVILEGES
           Dim lBufferNeeded As Long

           hdlProcessHandle = GetCurrentProcess()
           OpenProcessToken hdlProcessHandle, (TOKEN_ADJUST_PRIVILEGES Or _
              TOKEN_QUERY), hdlTokenHandle

        ' Get the LUID for shutdown privilege.
           LookupPrivilegeValue "", "SeShutdownPrivilege", tmpLuid

           tkp.PrivilegeCount = 1    ' One privilege to set
           tkp.TheLuid = tmpLuid
           tkp.Attributes = SE_PRIVILEGE_ENABLED

       ' Enable the shutdown privilege in the access token of this process.
           AdjustTokenPrivileges hdlTokenHandle, False, _
           tkp, Len(tkpNewButIgnored), tkpNewButIgnored, lBufferNeeded

       End Sub

4. Add a CommandButton to the form. In the Click event, add the following code:

        Private Sub Command1_Click()
           AdjustToken
           ExitWindowsEx (EWX_SHUTDOWN Or EWX_FORCE Or EWX_REBOOT), &HFFFF
        End Sub

5. Save the project and build an executable. When you run the executable and
  click the CommandButton the computer will reboot as expected.

STATUS
======

This behavior is by design.

REFERENCES
==========

For additional information, please see the following articles in the Microsoft
Knowledge Base:

  Q142820 HOWTO: Terminate Windows from a 16-Bit VB Application

  Q76981 VB3: HOWTO: Terminate Windows from a Visual Basic Application

  Q168796 HOWTO: Programmatically Restart or Log Off a Computer


Additional query words:

======================================================================
Keywords          : kbVBp400 kbVBp500 kbVBp600 kbGrpDSVB kb32bitOnly 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600 kbVB400Search kbVB400
Version           : WINDOWS:4.0,5.0,6.0
Issue type        : kbprb

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