[DUG] SmallPort under Vista

[Rohit Gupta]

Since the .manifest file is xml, you could modify it when the user 
configures the app to use the port.

Ross Levis wrote:
> I'm not sure how I'm going to resolve this Vista issue.
>
> I'm using a free Delphi component called SmallPort
> (http://www.torry.net/quicksearchd.php?String=smallport) for direct access
> to the LPT port under all versions of Windows from 95 to XP.
>
> It is an optional feature in my app to switch pins on the LPT port high &
> low which triggers external switch units.
>
> Unfortunately it is not working under Vista unless I force administrator
> privileges for my app.  It returns "Access is Denied".
>
> For 95/98/ME it uses a supplied VXD driver. For NT/2000/XP it uses a
> supplied .sys file which is loaded as a service.  It's using OpenSCManager,
> CreateService (with the .sys file) and StartService, etc.
>
> I know how to raise the privileges for the entire app using a manifest, but
> only about 5% of my users will be using this facility so mandatory elevation
> is not a solution.
>
> I've never used services before so this is a bit beyond me.  I have a couple
> of ideas in mind but I don't know if either will work.
>
> 1. Install this .sys file permanently as a service which starts when Windows
> starts.  It's a tiny thing so it's hardly going to use any resources.  I
> have no idea how to do this.
>
> Then modify the component to only open the service rather than create it.
> I'm still not sure if administrator access is required.  It could well be so
> this may not work. ???
>
> 2. Move the service code into a separate executable which has an
> administrator manifest and return the service handle back to the component
> in my app to use as required.  I would use shared memory for this
> communication.
>
> The question is, would the handle be valid in another app running in a
> different memory space?  I think it would be the address of the service in
> memory which would be static for all apps, so this may work.
>
> Option 2 is also not ideal as it would prompt to "Continue", or ask for an
> administrators password every time the app starts if the user is using this
> facility.
>
> I know some of you on this list create and use services so I'm interested to
> hear your suggestions.
>
> Thanks,
> Ross.
>
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