Edit

Querying a Service's Configuration

  • Article

A service configuration program uses the OpenService function to get a handle with SERVICE_QUERY_CONFIG access to an installed service object. The program can then use the service object handle in the QueryServiceConfig and QueryServiceConfig2 functions to retrieve the current configuration of the service.

In the following example, the DoQuerySvc function uses QueryServiceConfig and QueryServiceConfig2 to retrieve configuration information, then writes selected information to the console. The szSvcName variable is a global variable that contains the name of the service. For the complete example that sets this variable, see SvcConfig.cpp.

//
// Purpose: 
//   Retrieves and displays the current service configuration.
//
// Parameters:
//   None
// 
// Return value:
//   None
//
VOID __stdcall DoQuerySvc()
{
    SC_HANDLE schSCManager;
    SC_HANDLE schService;
    LPQUERY_SERVICE_CONFIG lpsc; 
    LPSERVICE_DESCRIPTION lpsd;
    DWORD dwBytesNeeded, cbBufSize, dwError; 

    // Get a handle to the SCM database. 
 
    schSCManager = OpenSCManager( 
        NULL,                    // local computer
        NULL,                    // ServicesActive database 
        SC_MANAGER_ALL_ACCESS);  // full access rights 
 
    if (NULL == schSCManager) 
    {
        printf("OpenSCManager failed (%d)\n", GetLastError());
        return;
    }

    // Get a handle to the service.

    schService = OpenService( 
        schSCManager,          // SCM database 
        szSvcName,             // name of service 
        SERVICE_QUERY_CONFIG); // need query config access 
 
    if (schService == NULL)
    { 
        printf("OpenService failed (%d)\n", GetLastError()); 
        CloseServiceHandle(schSCManager);
        return;
    }

    // Get the configuration information.
 
    if( !QueryServiceConfig( 
        schService, 
        NULL, 
        0, 
        &dwBytesNeeded))
    {
        dwError = GetLastError();
        if( ERROR_INSUFFICIENT_BUFFER == dwError )
        {
            cbBufSize = dwBytesNeeded;
            lpsc = (LPQUERY_SERVICE_CONFIG) LocalAlloc(LMEM_FIXED, cbBufSize);
        }
        else
        {
            printf("QueryServiceConfig failed (%d)", dwError);
            goto cleanup; 
        }
    }
  
    if( !QueryServiceConfig( 
        schService, 
        lpsc, 
        cbBufSize, 
        &dwBytesNeeded) ) 
    {
        printf("QueryServiceConfig failed (%d)", GetLastError());
        goto cleanup;
    }

    if( !QueryServiceConfig2( 
        schService, 
        SERVICE_CONFIG_DESCRIPTION,
        NULL, 
        0, 
        &dwBytesNeeded))
    {
        dwError = GetLastError();
        if( ERROR_INSUFFICIENT_BUFFER == dwError )
        {
            cbBufSize = dwBytesNeeded;
            lpsd = (LPSERVICE_DESCRIPTION) LocalAlloc(LMEM_FIXED, cbBufSize);
        }
        else
        {
            printf("QueryServiceConfig2 failed (%d)", dwError);
            goto cleanup; 
        }
    }
 
    if (! QueryServiceConfig2( 
        schService, 
        SERVICE_CONFIG_DESCRIPTION,
        (LPBYTE) lpsd, 
        cbBufSize, 
        &dwBytesNeeded) ) 
    {
        printf("QueryServiceConfig2 failed (%d)", GetLastError());
        goto cleanup;
    }
 
    // Print the configuration information.
 
    _tprintf(TEXT("%s configuration: \n"), szSvcName);
    _tprintf(TEXT("  Type: 0x%x\n"), lpsc->dwServiceType);
    _tprintf(TEXT("  Start Type: 0x%x\n"), lpsc->dwStartType);
    _tprintf(TEXT("  Error Control: 0x%x\n"), lpsc->dwErrorControl);
    _tprintf(TEXT("  Binary path: %s\n"), lpsc->lpBinaryPathName);
    _tprintf(TEXT("  Account: %s\n"), lpsc->lpServiceStartName);

    if (lpsd->lpDescription != NULL && lstrcmp(lpsd->lpDescription, TEXT("")) != 0)
        _tprintf(TEXT("  Description: %s\n"), lpsd->lpDescription);
    if (lpsc->lpLoadOrderGroup != NULL && lstrcmp(lpsc->lpLoadOrderGroup, TEXT("")) != 0)
        _tprintf(TEXT("  Load order group: %s\n"), lpsc->lpLoadOrderGroup);
    if (lpsc->dwTagId != 0)
        _tprintf(TEXT("  Tag ID: %d\n"), lpsc->dwTagId);
    if (lpsc->lpDependencies != NULL && lstrcmp(lpsc->lpDependencies, TEXT("")) != 0)
        _tprintf(TEXT("  Dependencies: %s\n"), lpsc->lpDependencies);
 
    LocalFree(lpsc); 
    LocalFree(lpsd);

cleanup:
    CloseServiceHandle(schService); 
    CloseServiceHandle(schSCManager);
}

Service Configuration

The Complete Service Sample