[python-win32] Querying the VNC Service fails sometimes

[Mike Driscoll]

Hi,

In one of my login scripts for work, I run a query to see if the VNC 
service is running using the win32serviceutil module. The code for that 
I am using looks something like this:

<code>
import win32serviceutil
serviceState = win32serviceutil.QueryServiceStatus('VNC Server')[1]
</code>

This works in 99.99% of cases. However, I have on user that keeps 
getting the following traceback:

Traceback (most recent call last):
  File "\\ourServer\pathName\PostLogon.py", line 207, in ?
    serviceState = win32serviceutil.QueryServiceStatus('VNC Server')[1]
  File "\\ourServer\pathName\Python24\lib\site-packages\win32\lib\win32serviceutil.py", line 479, in QueryServiceStatus
    hs = SmartOpenService(hscm, serviceName, win32service.SERVICE_QUERY_STATUS)
  File "\\ourServer\pathName\Python24\lib\site-packages\win32\lib\win32serviceutil.py", line 81, in SmartOpenService
    name = _GetServiceShortName(name)
  File "\\ourServer\pathName\Python24\lib\site-packages\win32\lib\win32serviceutil.py", line 62, in _GetServiceShortName
    skey = win32api.RegOpenKey(hkey, svc, 0, access)
error: (2, 'RegOpenKeyEx', 'The system cannot find the file specified.')


I used regmon to try and figure out what part of the Registry my code looks at and it appears to be looking for the "DisplayName" value in HKLM\SYSTEM\CurrentControlSet\Services\winvnc

I cannot see a difference in this user's registry versus my own, which does not have this issue. However, I can duplicate the error by connecting to the user's PC's registry using the _winreg module and querying the "DisplayName" value, like this:

QueryValue(key, 'DisplayName')

Which give me this traceback:

Traceback (most recent call last):
  File "<pyshell#14>", line 1, in <module>
    QueryValue(key, 'DisplayName')
WindowsError: [Error 2] The system cannot find the file specified

But if I use use _winreg's EnumValue, I get this:

>>> EnumValue(key, 4)
('DisplayName', u'VNC Server', 1)

What the!? Does anyone have any suggestions? Maybe a better way to get the information? I only need to know if the service is running or not, and if not, to start it.

Thanks!

-------------------
Mike Driscoll

Blog:   http://blog.pythonlibrary.org
Python Extension Building Network:     http://www.pythonlibrary.org