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Forcing a local or remote NT system to reboot

Author:

Steve McMahon(steve@vbaccelerator.com)

Keywords:

API,Windows

Updated:

09/08/98

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Under Windows NT, you can force a timed system shutdown on either the local machine or a remote network machine. This code tip shows how to do it. You can specifiy how long it will be before the machine will be shutdown in seconds (a zero value shuts down immediately), how remorseless the shutdown process should be (whether it allows any unsaved work to be saved) and whether the machine will be rebooted.

Start a new project in VB. Add a new module, then add the following code to it:

' To Determine if we are running NT or not:
Private Type OSVERSIONINFO
&nbsp &nbsp dwOSVersionInfoSize As Long
&nbsp &nbsp dwMajorVersion As Long
&nbsp &nbsp dwMinorVersion As Long
&nbsp &nbsp dwBuildNumber As Long
&nbsp &nbsp dwPlatformId As Long
&nbsp &nbsp &nbsp &nbsp szCSDVersion As String * 128
' Maintenance string for PSS usage
End Type
Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (lpVersionInformation As OSVERSIONINFO) As Long
Private Const VER_PLATFORM_WIN32_NT = 2
Private Const VER_PLATFORM_WIN32_WINDOWS = 1
Private Const VER_PLATFORM_WIN32s = 0

' To Report API errors:
Private Const FORMAT_MESSAGE_ALLOCATE_BUFFER = &H100
Private Const FORMAT_MESSAGE_ARGUMENT_ARRAY = &H2000
Private Const FORMAT_MESSAGE_FROM_HMODULE = &H800
Private Const FORMAT_MESSAGE_FROM_STRING = &H400
Private Const FORMAT_MESSAGE_FROM_SYSTEM = &H1000
Private Const FORMAT_MESSAGE_IGNORE_INSERTS = &H200
Private Const FORMAT_MESSAGE_MAX_WIDTH_MASK = &HFF
Private Declare Function FormatMessage Lib "kernel32" Alias "FormatMessageA" (ByVal dwFlags As Long, lpSource As Any, ByVal dwMessageId As Long, ByVal dwLanguageId As Long, ByVal lpBuffer As String, ByVal nSize As Long, Arguments As Long) As Long


' ============================================================================================
' NT Only
Private Type LARGE_INTEGER
&nbsp &nbsp LowPart As Long
&nbsp &nbsp HighPart As Long
End Type
Private Type LUID
&nbsp &nbsp LowPart As Long
&nbsp &nbsp HighPart As Long
End Type
Private Type LUID_AND_ATTRIBUTES
&nbsp &nbsp pLuid As LUID
&nbsp &nbsp Attributes As Long
End Type
Private Type TOKEN_PRIVILEGES
&nbsp &nbsp PrivilegeCount As Long
&nbsp &nbsp Privileges(0 To 0) As LUID_AND_ATTRIBUTES
End Type
Private Declare Function GetCurrentProcess Lib "kernel32" () As Long
Private Declare Function OpenProcessToken Lib "advapi32.dll" (ByVal ProcessHandle As Long, ByVal DesiredAccess As Long, TokenHandle As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function GetTokenInformation Lib "advapi32.dll" (ByVal TokenHandle As Long, TokenInformationClass As Integer, TokenInformation As Any, ByVal TokenInformationLength As Long, ReturnLength As Long) As Long
Private Declare Function AdjustTokenPrivileges Lib "advapi32.dll" (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
Private Declare Function LookupPrivilegeValue Lib "advapi32.dll" Alias "LookupPrivilegeValueA" (ByVal lpSystemName As String, ByVal lpName As String, lpLuid As LUID) As Long
Private Const SE_SHUTDOWN_NAME = "SeShutdownPrivilege"
Private Const SE_PRIVILEGE_ENABLED = &H2

Private Const READ_CONTROL = &H20000
Private Const STANDARD_RIGHTS_ALL = &H1F0000
Private Const STANDARD_RIGHTS_EXECUTE = (READ_CONTROL)
Private Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Private Const STANDARD_RIGHTS_REQUIRED = &HF0000
Private Const STANDARD_RIGHTS_WRITE = (READ_CONTROL)

Private Const TOKEN_ASSIGN_PRIMARY = &H1
Private Const TOKEN_DUPLICATE = (&H2)
Private Const TOKEN_IMPERSONATE = (&H4)
Private Const TOKEN_QUERY = (&H8)
Private Const TOKEN_QUERY_SOURCE = (&H10)
Private Const TOKEN_ADJUST_PRIVILEGES = (&H20)
Private Const TOKEN_ADJUST_GROUPS = (&H40)
Private Const TOKEN_ADJUST_DEFAULT = (&H80)
Private Const TOKEN_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ASSIGN_PRIMARY Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_DUPLICATE Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_IMPERSONATE Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_QUERY Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_QUERY_SOURCE Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_PRIVILEGES Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_GROUPS Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_DEFAULT)
Private Const TOKEN_READ = (STANDARD_RIGHTS_READ Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_QUERY)
Private Const TOKEN_WRITE = (STANDARD_RIGHTS_WRITE Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_PRIVILEGES Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_GROUPS Or _
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp TOKEN_ADJUST_DEFAULT)
Private Const TOKEN_EXECUTE = (STANDARD_RIGHTS_EXECUTE)

Private Const TokenDefaultDacl = 6
Private Const TokenGroups = 2
Private Const TokenImpersonationLevel = 9
Private Const TokenOwner = 4
Private Const TokenPrimaryGroup = 5
Private Const TokenPrivileges = 3
Private Const TokenSource = 7
Private Const TokenStatistics = 10
Private Const TokenType = 8
Private Const TokenUser = 1

Private Declare Function InitiateSystemShutdown Lib "advapi32.dll" Alias "InitiateSystemShutdownA" (ByVal lpMachineName As String, ByVal lpMessage As String, ByVal dwTimeout As Long, ByVal bForceAppsClosed As Long, ByVal bRebootAfterShutdown As Long) As Long
Private Declare Function AbortSystemShutdown Lib "advapi32.dll" Alias "AbortSystemShutdownA" (ByVal lpMachineName As String) As Long
' ============================================================================================

Public Function WinError(ByVal lLastDLLError As Long) As String
Dim sBuff As String
Dim lCount As Long
&nbsp &nbsp
&nbsp &nbsp
' Return the error message associated with LastDLLError:
&nbsp &nbsp sBuff = String$(256, 0)
&nbsp &nbsp lCount = FormatMessage( _
&nbsp &nbsp FORMAT_MESSAGE_FROM_SYSTEM Or FORMAT_MESSAGE_IGNORE_INSERTS, _
&nbsp &nbsp 0, lLastDLLError, 0&, sBuff, Len(sBuff), ByVal 0)
&nbsp &nbsp If lCount Then
&nbsp &nbsp WinError = Left$(sBuff, lCount)
&nbsp &nbsp End If
&nbsp &nbsp
End Function

Public Function IsNT() As Boolean
Static bOnce As Boolean
Static bValue As Boolean

&nbsp &nbsp
' Return whether the system is running NT or not:
&nbsp &nbsp If Not (bOnce) Then
&nbsp &nbsp Dim tVI As OSVERSIONINFO
&nbsp &nbsp tVI.dwOSVersionInfoSize = Len(tVI)
&nbsp &nbsp If (GetVersionEx(tVI) 0) Then
&nbsp &nbsp &nbsp &nbsp bValue = (tVI.dwPlatformId = VER_PLATFORM_WIN32_NT)
&nbsp &nbsp &nbsp &nbsp bOnce = True
&nbsp &nbsp End If
&nbsp &nbsp End If
&nbsp &nbsp IsNT = bValue
&nbsp &nbsp
End Function

Private Function NTEnableShutDown(ByRef sMsg As String) As Boolean
Dim tLUID As LUID
Dim hProcess As Long
Dim hToken As Long
Dim tTP As TOKEN_PRIVILEGES, tTPOld As TOKEN_PRIVILEGES
Dim lTpOld As Long
Dim lR As Long

&nbsp &nbsp
' Under NT we must enable the SE_SHUTDOWN_NAME privilege in the
&nbsp &nbsp ' process we're trying to shutdown from, otherwise a call to
&nbsp &nbsp ' try to shutdown has no effect!

&nbsp &nbsp
' Find the LUID of the Shutdown privilege token:
&nbsp &nbsp lR = LookupPrivilegeValue(vbNullString, SE_SHUTDOWN_NAME, tLUID)
&nbsp &nbsp
&nbsp &nbsp
' If we get it:
&nbsp &nbsp If (lR 0) Then
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
&nbsp &nbsp
' Get the current process handle:
&nbsp &nbsp hProcess = GetCurrentProcess()
&nbsp &nbsp If (hProcess 0) Then
&nbsp &nbsp &nbsp &nbsp
' Open the token for adjusting and querying (if we can - user may not have rights):
&nbsp &nbsp &nbsp &nbsp lR = OpenProcessToken(hProcess, TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY, hToken)
&nbsp &nbsp &nbsp &nbsp If (lR 0) Then
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
' Ok we can now adjust the shutdown priviledges:
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp With tTP
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp .PrivilegeCount = 1
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp With .Privileges(0)
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp .Attributes = SE_PRIVILEGE_ENABLED
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp .pLuid.HighPart = tLUID.HighPart
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp .pLuid.LowPart = tLUID.LowPart
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp End With
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp End With
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
' Now allow this process to shutdown the system:
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp lR = AdjustTokenPrivileges(hToken, 0, tTP, Len(tTP), tTPOld, lTpOld)
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp If (lR 0) Then
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp NTEnableShutDown = True
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp Else
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp Err.Raise eeSSDErrorBase + 6, App.EXEName & ".mShutDown", "Can't enable shutdown: You do not have the privileges to shutdown this system. [" & WinError(Err.LastDllError) & "]"
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp End If
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp
' Remember to close the handle when finished with it:
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp CloseHandle hToken
&nbsp &nbsp &nbsp &nbsp Else
&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp Err.Raise eeSSDErrorBase + 6, App.EXEName & ".mShutDown", "Can't enable shutdown: You do not have the privileges to shutdown this system. [" & WinError(Err.LastDllError) & "]"
&nbsp &nbsp &nbsp &nbsp End If
&nbsp &nbsp Else
&nbsp &nbsp &nbsp &nbsp Err.Raise eeSSDErrorBase + 5, App.EXEName & ".mShutDown", "Can't enable shutdown: Can't determine the current process. [" & WinError(Err.LastDllError) & "]"
&nbsp &nbsp End If
&nbsp &nbsp Else
&nbsp &nbsp Err.Raise eeSSDErrorBase + 4, App.EXEName & ".mShutDown", "Can't enable shutdown: Can't find the SE_SHUTDOWN_NAME privilege value. [" & WinError(Err.LastDllError) & "]"
&nbsp &nbsp End If

End Function

Public Function NTForceTimedShutdown( _
&nbsp &nbsp Optional ByVal lTimeOut As Long = -1, _
&nbsp &nbsp Optional ByVal sMsg As String = "", _
&nbsp &nbsp Optional ByVal sMachineNetworkName As String = vbNullString, _
&nbsp &nbsp Optional ByVal bForceAppsToClose As Boolean = False, _
&nbsp &nbsp Optional ByVal bReboot As Boolean = False _
&nbsp &nbsp ) As Boolean
Dim lR As Long
&nbsp &nbsp
&nbsp &nbsp If IsNT Then
&nbsp &nbsp
' Make sure we have enabled the privilege to shutdown
&nbsp &nbsp ' for this process if we're running NT:
&nbsp &nbsp If Not (NTEnableShutDown(sMsg)) Then
&nbsp &nbsp &nbsp &nbsp Exit Function
&nbsp &nbsp End If
&nbsp &nbsp
&nbsp &nbsp
' This is the code to do a timed shutdown:
&nbsp &nbsp lR = InitiateSystemShutdown(sMachineNetworkName, sMsg, lTimeOut, bForceAppsToClose, bReboot)
&nbsp &nbsp If (lR = 0) Then
&nbsp &nbsp &nbsp &nbsp Err.Raise eeSSDErrorBase + 2, App.EXEName & ".mShutDown", "InitiateSystemShutdown failed: " & WinError(Err.LastDllError)
&nbsp &nbsp End If
&nbsp &nbsp
&nbsp &nbsp Else
&nbsp &nbsp Err.Raise eeSSDErrorBase + 1, App.EXEName & ".mShutDown", "Function only available under Windows NT."
&nbsp &nbsp End If
&nbsp &nbsp
End Function

Public Function NTAbortTimedShutdown( _
&nbsp &nbsp Optional ByVal sMachineNetworkName As String = vbNullString _
)
AbortSystemShutdown sMachineNetworkName
End Function

To try out a shutdown, add two Command buttons and a Text box to the project's form and then paste in the following code. Note you should save your work before running it, because the shutdown will kill VB without asking you to save any changes! Clicking on the first Command button will initiate a shutdown, with a timeout value set to the number of seconds entered into the text box. To stop the shutdown, click the second Command button.

Private Sub Command1_Click()
&nbsp &nbsp If (MsgBox("Are you sure you want to initiate a forced, timed shutdown?", vbYesNo Or vbQuestion) = vbYes) Then
&nbsp &nbsp NTForceTimedShutdown CLng(Text1.Text), "You're gonna get shutdown in " & Text1.Text & " s..."
End If
End Sub

Private Sub Command2_Click()
NTAbortTimedShutdown
End Sub

Private Sub Form_Load()
Text1.Text = 60
End Sub


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Copyright 1998-1999, Steve McMahon ( steve@vbaccelerator.com). All Rights Reserved.
Last updated: 09/08/98