HOWTO: Query an NT Service for Status and Configuration

ID: Q189633

The information in this article applies to:

Microsoft Visual Basic Control Creation, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0

SUMMARY

This article provides sample code that demonstrates querying an NT Service's Status and Configuration from Visual Basic.

MORE INFORMATION

Step-by-Step Example

Start a New Standard EXE Project in Visual Basic. Form1 is created by default.

Add a Text Box, Command Button, and a List Box to Form1.

Remove "Text1" from the Text property of Text1.

Paste the following code into the declarations section of Form1


   Option Explicit

   Private Declare Function CloseServiceHandle Lib "advapi32.dll" _
      (ByVal hSCObject As Long) As Long

   Private Declare Function QueryServiceStatus Lib "advapi32.dll" _
      (ByVal hService As Long, _
      lpServiceStatus As SERVICE_STATUS) As Long

   Private Declare Function OpenService Lib "advapi32.dll" _
      Alias "OpenServiceA" _
      (ByVal hSCManager As Long, _
      ByVal lpServiceName As String, _
      ByVal dwDesiredAccess As Long) As Long

   Private Declare Function OpenSCManager Lib "advapi32.dll" _
      Alias "OpenSCManagerA" _
      (ByVal lpMachineName As String, _
      ByVal lpDatabaseName As String, _
      ByVal dwDesiredAccess As Long) As Long

   Private Declare Function QueryServiceConfig Lib "advapi32.dll" _
      Alias "QueryServiceConfigA" _
      (ByVal hService As Long, _
      lpServiceConfig As Byte, _
      ByVal cbBufSize As Long, _
      pcbBytesNeeded As Long) As Long

   Private Declare Sub CopyMemory Lib "KERNEL32" Alias "RtlMoveMemory" _
      (hpvDest As Any, _
      hpvSource As Any, _
      ByVal cbCopy As Long)

   Private Declare Function lstrcpy Lib "KERNEL32" Alias "lstrcpyA" _
      (ByVal lpString1 As String, _
      ByVal lpString2 As Long) As Long

   Private Type SERVICE_STATUS
      dwServiceType As Long
      dwCurrentState As Long
      dwControlsAccepted As Long
      dwWin32ExitCode As Long
      dwServiceSpecificExitCode As Long
      dwCheckPoint As Long
      dwWaitHint As Long
   End Type

   Private Type QUERY_SERVICE_CONFIG
      dwServiceType As Long
      dwStartType As Long
      dwErrorControl As Long
      lpBinaryPathName As Long 'String
      lpLoadOrderGroup As Long ' String
      dwTagId As Long
      lpDependencies As Long 'String
      lpServiceStartName As Long 'String
      lpDisplayName As Long  'String
   End Type

   Private Const SERVICE_STOPPED = &H1
   Private Const SERVICE_START_PENDING = &H2
   Private Const SERVICE_STOP_PENDING = &H3
   Private Const SERVICE_RUNNING = &H4
   Private Const SERVICE_CONTINUE_PENDING = &H5
   Private Const SERVICE_PAUSE_PENDING = &H6
   Private Const SERVICE_PAUSED = &H7
   Private Const SERVICE_ACCEPT_STOP = &H1
   Private Const SERVICE_ACCEPT_PAUSE_CONTINUE = &H2
   Private Const SERVICE_ACCEPT_SHUTDOWN = &H4
   Private Const SC_MANAGER_CONNECT = &H1
   Private Const SERVICE_INTERROGATE = &H80
   Private Const GENERIC_READ = &H80000000
   Private Const ERROR_INSUFFICIENT_BUFFER = 122

   Private Sub Command1_Click()
      Dim hSCM  As Long
      Dim hSVC As Long
      Dim pSTATUS As SERVICE_STATUS
      Dim udtConfig As QUERY_SERVICE_CONFIG
      Dim lRet As Long
      Dim lBytesNeeded As Long
      Dim sTemp As String
      Dim pFileName As Long

   List1.Clear

      ' Open The Service Control Manager
      '
      hSCM = OpenSCManager(vbNullString, vbNullString, SC_MANAGER_CONNECT)
      If hSCM = 0 Then
         MsgBox "Error - " & Err.LastDllError
      End If

      ' Open the specific Service to obtain a handle
      '
      hSVC = OpenService(hSCM, Trim(Text1.Text), GENERIC_READ)
         If hSVC = 0 Then
            MsgBox "Error - " & Err.LastDllError
            GoTo CloseHandles
         End If

      ' Fill the Service Status Structure
      '
      lRet = QueryServiceStatus(hSVC, pSTATUS)
      If lRet = 0 Then
         MsgBox "Error - " & Err.LastDllError
         GoTo CloseHandles
      End If

      ' Report the Current State
      '
      Select Case pSTATUS.dwCurrentState
      Case SERVICE_STOPPED
         sTemp = "The Service is Stopped"
      Case SERVICE_START_PENDING
         sTemp = "The Service Being Started"
      Case SERVICE_STOP_PENDING
         sTemp = "The Service is in the process of being stopped"
      Case SERVICE_RUNNING
         sTemp = "The Service is Running"
      Case SERVICE_CONTINUE_PENDING
         sTemp = "The Service is in the process of being Continued"
      Case SERVICE_PAUSE_PENDING
         sTemp = "The Service is in the process of being Paused"
      Case SERVICE_PAUSED
         sTemp = "The Service is Paused"
      Case SERVICE_ACCEPT_STOP
         sTemp = "The Service is Stopped"
      Case SERVICE_ACCEPT_PAUSE_CONTINUE
         sTemp = "The Service is "
      Case SERVICE_ACCEPT_SHUTDOWN
         sTemp = "The Service is being Shutdown"
      End Select

      List1.AddItem "Service Status : " & sTemp

      ' Call QueryServiceConfig with 1 byte buffer to generate an error
      ' that returns the size of a buffer we need.
      '
      ReDim abConfig(0) As Byte
      lRet = QueryServiceConfig(hSVC, abConfig(0), 0&, lBytesNeeded)
      If lRet = 0 And Err.LastDllError <> ERROR_INSUFFICIENT_BUFFER Then
         MsgBox "Error - " & Err.LastDllError
      End If

      ' Redim our byte array to the size necessary and call
      ' QueryServiceConfig again
      '
      ReDim abConfig(lBytesNeeded) As Byte
      lRet = QueryServiceConfig(hSVC, abConfig(0), lBytesNeeded, _
         lBytesNeeded)
      If lRet = 0 Then
         MsgBox "Error - " & Err.LastDllError
         GoTo CloseHandles
      End If

      ' Fill our Service Config User Defined Type.
      '
      CopyMemory udtConfig, abConfig(0), Len(udtConfig)

      List1.AddItem "Service Type: " & udtConfig.dwServiceType
      List1.AddItem "Service Start Type: " & udtConfig.dwStartType
      List1.AddItem "Service Error Control: " & udtConfig.dwErrorControl

      sTemp = Space(255)

      ' Now use the pointer obtained to copy the path into the temporary
      ' String Variable
      '
      lRet = lstrcpy(sTemp, udtConfig.lpBinaryPathName)
      List1.AddItem "Service Binary Path: " & sTemp

      lRet = lstrcpy(sTemp, udtConfig.lpDependencies)
      List1.AddItem "Service Dependencies: " & sTemp

      lRet = lstrcpy(sTemp, udtConfig.lpDisplayName)
      List1.AddItem "Service DisplayName: " & sTemp

      lRet = lstrcpy(sTemp, udtConfig.lpLoadOrderGroup)
      List1.AddItem "Service LoadOrderGroup: " & sTemp

      lRet = lstrcpy(sTemp, udtConfig.lpServiceStartName)
      List1.AddItem "Service Start Name: " & sTemp

   CloseHandles:
   ' Close the Handle to the Service
   '
      CloseServiceHandle (hSVC)

   ' Close the Handle to the Service Control Manager
   '
      CloseServiceHandle (hSCM)

   End Sub

Run the sample and type the Service Name in the Text box. For this example type in "Eventlog" without the quotes.

NOTE: This is not necessarily the same as the "Display Name" that shows in the Services applet of the Control Panel. The Service names registered on the system can be located under the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

Click the CommandButton.

The results displayed in the list box should be similar to the following:


      Service Status : The Service is Running
      Service Type: 32
      Service Start Type: 2
      Service Error Control: 1
      Service Binary Path: C:\WINNT\system32\services.exe
      Service Dependencies:

      Service DisplayName: EventLog
      Service LoadOrderGroup: Event log
      Service Start Name: LocalSystem

REFERENCES

See the March 1997 MSDN article - "Using Visual Basic Classes to Query Windows NT Services"

Additional query words: kbDSupport kbVBp500 kbRegistry kbVBp kbWinNT Kbdss kbVBp600


Keywords          : 
Version           : 
Platform          : WINDOWS 
Issue type        : kbhowto

Last Reviewed: May 24, 1999