Re: Communication Driver Hooks

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: ZG (stopspam_zhigang_at_ybwork.com_nospam)
Date: 01/19/05 

Date: Wed, 19 Jan 2005 21:00:45 +1100

If my memory is right, I remeber that there is a comm-hook sample in
VToolsD. 

-- 
Regards,
ZG [@ Sydney]
Windows Driver Developer/Service
[Remove 'stopspam' & 'nospam' when you send email to me]
"Christopher Lansing" <c_lansing@hotmail.com> wrote in message 
news:OQJ8PdC$EHA.2104@TK2MSFTNGP14.phx.gbl...
>I am trying to do something which I am sure will haev many of you screaming 
>"You don't want to do that."  I want ot write what amounts to a bit bucket 
>for communication ports.  In particular I want to be able to plug it in 
>after the fact as a dynamically loaded driver, have all data written to an 
>arbitrary COM port or modem tossed in the bit bucket and the driver report 
>back that all data was successfully written.  The obvious approach to this 
>(to me) was to hook the _VCOMM_WriteComm service, set up number of 
>characters written and the return value appropriately, and never call the 
>real _VCOMM_WriteComm (very dangerous I'm sure).
>
> A small test program that opens COM1, writes a test string and reports 
> back the number of characters written fails to return from writing to the 
> COM port while my hook is installed.  I already know from other tests that 
> the hook is properly installed, and that the test program works.
>
> Is there more than just _VCOMM_WriteComm that needs to be hooked to do 
> this?  Is there a better or safer way to approach the bit bucket problem? 
> Any tips will be greatly appreciated.
>
> By the way, I'm just using the regular win 9x DDK without WDM (at least 
> for now, but that may change later).
>
> Thanks,
> Christopher Lansing

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