Imports System.Runtime.InteropServices
Imports System.ComponentModel
Imports System.Text
Imports System.Diagnostics
Public Class WtsApi
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
Public Structure WTS_SESSION_INFO
Public SessionId As Integer
<MarshalAs(UnmanagedType.LPStr)> Public pWinStationName As String
Public state As WTS_CONNECTSTATE_CLASS
End Structure
Public Class WtsSession
Public SessionId As Integer
Public StationName As String
Public ConnectionState As WTS_CONNECTSTATE_CLASS
Public UserDomain As String
Public UserName As String
Public UserSid As String
End Class
Public Enum WTS_CONNECTSTATE_CLASS
WTSActive
WTSConnected
WTSConnectQuery
WTSShadow
WTSDisconnected
WTSIdle
WTSListen
WTSReset
WTSDown
WTSInit
End Enum
Public Enum WTS_INFO_CLASS
WTSInitialProgram = 0
WTSApplicationName = 1
WTSWorkingDirectory = 2
WTSOEMId = 3
WTSSessionId = 4
WTSUserName = 5
WTSWinStationName = 6
WTSDomainName = 7
WTSConnectState = 8
WTSClientBuildNumber = 9
WTSClientName = 10
WTSClientDirectory = 11
WTSClientProductId = 12
WTSClientHardwareId = 13
WTSClientAddress = 14
WTSClientDisplay = 15
WTSClientProtocolType = 16
WTSIdleTime = 17
WTSLogonTime = 18
WTSIncomingBytes = 19
WTSOutgoingBytes = 20
WTSIncomingFrames = 21
WTSOutgoingFrames = 22
End Enum
'WTSQueryUserToken errors
Private Const ERROR_PRIVILEGE_NOT_HELD As Integer = 1314 'needs tcb privilege
Private Const ERROR_INVALID_PARAMETER As Integer = 87
Private Const ERROR_ACCESS_DENIED As Integer = 5 'has tcb privilege, but it must be running as LocalSystem
Private Const ERROR_CTX_WINSTATION_NOT_FOUND As Integer = 7022
Private Const ERROR_NO_TOKEN As Integer = 1008
Private Const WTS_NO_SESSION As Integer = &HFFFFFFFF
Private Const WTS_CURRENT_SERVER_HANDLE As Long = 0
Private Const WTS_CURRENT_SESSION As Long = -1
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSEnumerateSessions( _
ByVal hServer As IntPtr, _
<MarshalAs(UnmanagedType.U4)> ByVal Reserved As Integer, _
<MarshalAs(UnmanagedType.U4)> ByVal Version As Integer, _
ByRef ppSessionInfo As IntPtr, _
<MarshalAs(UnmanagedType.U4)> ByRef pCount As Integer) As Integer
End Function
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSQuerySessionInformation( _
ByVal hServer As Integer, _
ByVal SessionId As Integer, _
ByVal InfoClass As WTS_INFO_CLASS, _
ByRef ppBuffer As IntPtr, _
ByRef pCount As Int32) As Integer
End Function
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSFreeMemory( _
ByVal memory As IntPtr) As Integer
End Function
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSOpenServer( _
ByVal pServerName As String) As IntPtr
End Function
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Sub WTSCloseServer( _
ByVal hServer As IntPtr)
End Sub
<DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Public Shared Function WTSGetActiveConsoleSessionId() As Integer
End Function
<DllImport("Wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSDisconnectSession( _
ByVal hServer As Integer, _
ByVal SessionID As Integer, _
ByVal bWait As Boolean) As Integer
End Function
<DllImport("Wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSLogoffSession( _
ByVal hServer As Integer, _
ByVal Sessionid As Integer, _
ByVal bWait As Boolean) As Integer
End Function
<DllImport("Wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Public Shared Function WTSQueryUserToken( _
ByVal Sessionid As Integer, _
ByRef pHandle As IntPtr) As Integer
End Function
Public Shared Function WaitForSessionRelease(ByVal username As String, ByVal milliseconds As Integer) As Boolean
Dim began As DateTime = Now
While Now <= began.AddMilliseconds(milliseconds)
If WtsApi.UserIsLoggedIn(username) Then
Logger.WriteEntry("Waiting for session to release: " + username, EventLogEntryType.Warning)
System.Threading.Thread.Sleep(milliseconds)
Else
Return True
End If
End While
Return False
End Function
'Public Shared Function WaitForSessionRelease(ByVal sessionId As Integer, ByVal milliseconds As Integer) As Boolean
' Dim began As DateTime = Now
' While Now < began.AddMilliseconds(milliseconds)
' Try
' If Not String.IsNullOrEmpty(GetSessionInfo(sessionId, WTS_INFO_CLASS.WTSConnectState)) Then
' 'continue
' End If
' Catch ex As Exception
' 'session went out of scope
' Return True
' End Try
' System.Threading.Thread.Sleep(500)
' End While
' Return False
'End Function
Public Shared Function UserIsLoggedIn(ByVal username As String) As Boolean
Try
If WtsApi.GetSession(username) Is Nothing Then
Return False
Else
Return True
End If
Catch ex As Exception
Return True
End Try
End Function
Public Shared Function GetUserToken(ByVal sessionID As Integer) As IntPtr
Dim result As Integer
Dim token As IntPtr = IntPtr.Zero
KernelApi.AddPrivilege(KernelApi.SE_TCB_PRIVILEGE)
result = WTSQueryUserToken(sessionID, token)
If result = 0 Then
Throw New Win32Exception(Marshal.GetLastWin32Error())
End If
Return token
End Function
Public Shared Function GetUserName(ByVal sessionID As Integer) As String
Return GetSessionInfo(sessionID, WTS_INFO_CLASS.WTSUserName)
End Function
Public Shared Function GetUserDomain(ByVal sessionID As Integer) As String
Return GetSessionInfo(sessionID, WTS_INFO_CLASS.WTSDomainName)
End Function
Public Shared Function GetUserNameFull(ByVal sessionid As Integer) As String
Return GetUserDomain(sessionid).ToUpper() + "\" + GetUserName(sessionid)
End Function
Public Shared Function GetCurrentSessionId() As Integer
Return CInt(GetSessionInfo(WTS_CURRENT_SESSION, WTS_INFO_CLASS.WTSSessionId))
End Function
Public Shared Function GetCurrentSessionInfo(ByVal info As WTS_INFO_CLASS) As String
Return GetSessionInfo(WTS_CURRENT_SESSION, info)
End Function
Public Shared Function GetSessionInfo(ByVal sessionID As Integer, ByVal info As WTS_INFO_CLASS) As String
Dim ret As String = ""
Dim ppBuffer As IntPtr = IntPtr.Zero
Dim bufSize As Integer
Dim result As Integer
Try
result = WTSQuerySessionInformation(WTS_CURRENT_SERVER_HANDLE, sessionID, info, ppBuffer, bufSize)
If result = 0 Then
Throw New Win32Exception(Marshal.GetLastWin32Error())
End If
Select Case info
Case WTS_INFO_CLASS.WTSApplicationName
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSClientName
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSDomainName
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSInitialProgram
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSUserName
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSWinStationName
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSWorkingDirectory
ret = Marshal.PtrToStringAuto(ppBuffer)
Case WTS_INFO_CLASS.WTSConnectState
ret = CType(Marshal.ReadInt32(ppBuffer), WTS_CONNECTSTATE_CLASS).ToString()
Case WTS_INFO_CLASS.WTSSessionId
ret = Convert.ToString(Marshal.ReadInt32(ppBuffer))
Case Else
Throw New ArgumentOutOfRangeException(info.ToString())
End Select
Return ret
Finally
WTSFreeMemory(ppBuffer)
End Try
End Function
Public Shared Function GetSession(ByVal username As String) As WtsSession
username = Utilities.GetUserName(username)
For Each s As WtsApi.WtsSession In WtsApi.GetSessions()
If Utilities.GetUserName(s.UserName).ToLower() = username.ToLower() Then
Return s
End If
Next
Return Nothing
End Function
Public Shared Function GetActiveSession() As WtsSession
Dim retries As Integer = 0
Try
Retry:
Dim sessions() As WtsApi.WtsSession = WtsApi.GetSessions()
'priority to WtsActive sessions
For Each s As WtsApi.WtsSession In sessions
If s.ConnectionState = WTS_CONNECTSTATE_CLASS.WTSActive Then
Return s
End If
Next
For Each s As WtsApi.WtsSession In sessions
If s.ConnectionState = WTS_CONNECTSTATE_CLASS.WTSConnected Then
Return s
End If
Next
Catch ex As Exception
If retries < 3 Then
retries += 1
Threading.Thread.Sleep(500)
GoTo Retry
End If
Logger.WriteEntry("Error retrieving active session: " + ex.Message, EventLogEntryType.Error)
End Try
Return Nothing
End Function
Public Shared Function ActiveSessionIsLoggedIn() As Boolean
Dim s As WtsApi.WtsSession
s = GetActiveSession()
If s Is Nothing Then
Return False
ElseIf s.UserName = "" Then
Return False
Else
Return True
End If
End Function
Public Shared Function GetSession(ByVal sessionId As Integer) As WtsSession
For Each s As WtsSession In WtsApi.GetSessions()
If s.SessionId = sessionId Then
Return s
End If
Next
Return Nothing
End Function
Public Shared Function GetSessions() As WtsSession()
Dim ppSessionInfo As IntPtr = IntPtr.Zero
Dim result As Integer
Dim sessionCount As Integer
Dim structSize As Integer
Dim structIndexer As Integer
Try
result = WTSEnumerateSessions(IntPtr.Zero, 0, 1, ppSessionInfo, sessionCount)
If result = 0 Then
Throw New Win32Exception(Marshal.GetLastWin32Error())
End If
structSize = Marshal.SizeOf(GetType(WTS_SESSION_INFO))
structIndexer = CInt(ppSessionInfo)
Dim sessions(sessionCount - 1) As WtsSession
For i As Integer = 0 To sessionCount - 1
Dim si As WTS_SESSION_INFO
si = CType(Marshal.PtrToStructure(CType(structIndexer, IntPtr), GetType(WTS_SESSION_INFO)), WTS_SESSION_INFO)
sessions(i) = New WtsSession()
sessions(i).SessionId = si.SessionId
sessions(i).ConnectionState = si.state
sessions(i).StationName = si.pWinStationName
Dim domain As String = GetSessionInfo(si.SessionId, WTS_INFO_CLASS.WTSDomainName)
Dim user As String = GetSessionInfo(si.SessionId, WTS_INFO_CLASS.WTSUserName)
sessions(i).UserDomain = domain
sessions(i).UserName = user
sessions(i).UserSid = KernelApi.GetSID(domain + "\" + user)
structIndexer += structSize
Next
Return sessions
Catch ex As Exception
Throw New ApplicationException("Error enumerating WtsSessions: " + ex.Message)
Finally
WTSFreeMemory(ppSessionInfo)
End Try
End Function
Public Shared Sub LogoffSession(ByVal sessionId As Integer, ByVal synchronous As Boolean)
Dim result As Integer
result = WtsApi.WTSLogoffSession(WTS_CURRENT_SERVER_HANDLE, sessionId, synchronous)
If result = 0 Then
Throw New Win32Exception(Marshal.GetLastWin32Error())
End If
End Sub
Public Shared Sub DisconnectSession(ByVal sessionId As Integer, ByVal synchronous As Boolean)
Dim result As Integer
result = WtsApi.WTSDisconnectSession(WTS_CURRENT_SERVER_HANDLE, sessionId, synchronous)
If result = 0 Then
Throw New Win32Exception(Marshal.GetLastWin32Error())
End If
End Sub
Public Shared Function AllUsersLoggedOff() As Boolean
For Each s As WtsSession In WtsApi.GetSessions()
If s.UserName <> "" Then Return False
Next
Return True
End Function
Public Shared Function WaitForConnectedSession(ByVal timeoutMilliseconds As Integer) As WtsSession
Dim session As WtsSession = Nothing
Dim elapsed As Integer = 0
While elapsed < timeoutMilliseconds
Try
For Each s As WtsSession In WtsApi.GetSessions()
If s.ConnectionState = WTS_CONNECTSTATE_CLASS.WTSConnected Then
session = s
Exit While
End If
Next
Catch ex As Exception
'ignore
End Try
Threading.Thread.Sleep(500)
elapsed += 500
End While
Return session
End Function
End Class
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