Log Off a User? *[resolved]*

[ProgrammerJon]

How can I make my vb.net program log off a user?

[jim mcnamara]

I just quickly hacked some code to shutdown Win2K into logoff a user. You call ExitWindowsEx after you adjust privileges.
This logs a user off a local machine.

This is just api calls in VB 6.0 - not .NET, but you should be able to translate the calls back to .NET framework.

Option Explicit
Private Const EWX_SHUTDOWN As Long = 1
Private Const EWX_REBOOT As Long = 2
Private Const EWX_FORCE As Long = 4
Private Const EWX_POWEROFF As Long = 8
Private Const EWX_LOGOFF as Long = 0
'The ExitWindowsEx function either logs off, shuts down, or shuts
'down and restarts the system.

Private Declare Function ExitWindowsEx Lib "user32" _
    (ByVal dwOptions As Long, _
    ByVal dwReserved As Long) As Long
'The GetLastError function returns the calling thread's last-error
'code value. The last-error code is maintained on a per-thread basis.
'Multiple threads do not overwrite each other's last-error code.
Private Declare Function GetLastError Lib "kernel32" () As Long
Private Const mlngWindows95 = 0
Private Const mlngWindowsNT = 1
Public glngWhichWindows32 As Long
'The GetVersion function returns the operating system in use.
Private Declare Function GetVersion Lib "kernel32" () As Long
Private Type LUID
    UsedPart As Long
    IgnoredForNowHigh32BitPart As Long
End Type
Private Type LUID_AND_ATTRIBUTES
    TheLuid As LUID
    Attributes As Long
End Type
Private Type TOKEN_PRIVILEGES
    PrivilegeCount As Long
    TheLuid As LUID
    Attributes As Long
End Type
'The GetCurrentProcess function returns a pseudohandle for the
'current process.
Private Declare Function GetCurrentProcess Lib "kernel32" () As Long
'The OpenProcessToken function opens the access token associated with
'a process.
Private Declare Function OpenProcessToken Lib "advapi32" _
    (ByVal ProcessHandle As Long, _
    ByVal DesiredAccess As Long, _
    TokenHandle As Long) As Long
'The LookupPrivilegeValue function retrieves the locally unique
'identifier (LUID) used on a specified system to locally represent
'the specified privilege name.
Private Declare Function LookupPrivilegeValue Lib "advapi32" _
    Alias "LookupPrivilegeValueA" _
    (ByVal lpSystemName As String, _
    ByVal lpName As String, _
    lpLuid As LUID) As Long
'The AdjustTokenPrivileges function enables or disables privileges
'in the specified access token. Enabling or disabling privileges
'in an access token requires TOKEN_ADJUST_PRIVILEGES access.
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
Private Declare Sub SetLastError Lib "kernel32" (ByVal dwErrCode As Long)

Private Sub AdjustToken()
'********************************************************************
'* This procedure sets the proper privileges to allow a log off or a
'* shut down to occur under Windows NT.
'********************************************************************
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
'Set the error code of the last thread to zero using the
'SetLast Error function. Do this so that the GetLastError
'function does not return a value other than zero for no
'apparent reason.
    SetLastError 0
'Use the GetCurrentProcess function to set the hdlProcessHandle
'variable.
    hdlProcessHandle = GetCurrentProcess()
'    If GetLastError <> 0 Then
'        systemMessage.AddItem "GetCurrentProcess Error==" & GetLastError
'    End If
    OpenProcessToken hdlProcessHandle, _
        (TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY), hdlTokenHandle
'    If GetLastError <> 0 Then
'        systemMessage.AddItem "OpenProcessToken Error==" & GetLastError
'    End If
'Get the LUID for shutdown privilege
    LookupPrivilegeValue "", "SeShutdownPrivilege", tmpLuid
'    If GetLastError <> 0 Then
'        systemMessage.AddItem "LookupPrivilegeValue Error==" & GetLastError
'    End If
    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
'    If GetLastError <> 0 Then
'        systemMessage.AddItem "AdjustTokenPrivileges Error==" & GetLastError
'    End If
End Sub

Private Sub cmdShutdown_Click()
    If glngWhichWindows32 = mlngWindowsNT Then
        AdjustToken
'        systemMessage.AddItem "Post-AdjustToken GetLastError " & GetLastError
    End If
    ExitWindowsEx (EWX_LOGOFF), &HFFFF
'    systemMessage.AddItem "ExitWindowsEx's GetLastError " & GetLastError
End Sub

Private Sub cmdForceShutdown_Click()
    If glngWhichWindows32 = mlngWindowsNT Then
        AdjustToken
'        systemMessage.AddItem "Post-AdjustToken GetLastError " & GetLastError
    End If
    ExitWindowsEx (EWX_LOGOFF Or EWX_FORCE), &HFFFF
'    systemMessage.AddItem "ExitWindowsEx's GetLastError " & GetLastError
End Sub

Public Sub Main()
'********************************************************************
'* When the project starts, check the operating system used by
'* calling the GetVersion function.
'********************************************************************
Dim lngVersion As Long
    lngVersion = GetVersion()
    If ((lngVersion And &H80000000) = 0) Then
        glngWhichWindows32 = mlngWindowsNT
'        systemType.Text = "Windows NT"
    Else
        glngWhichWindows32 = mlngWindows95
'        systemType.Text = "Windows 95"
    End If
Call cmdForceShutdown_Click
End
End Sub

[ProgrammerJon]

That's pretty complex, is there a different way?

[Pirate]

Originally posted by ProgrammerJon
That's pretty complex, is there a different way?

I know this's been resolved but may others can get benefit too.