Disabling Local Input

[Keith Adeney]

Disabling local input should just be a case of making WinVNC block any
keyboard or mouse messages it sees in it's dll message hook. Making
anyone near the computer continue to see the screen saver, or a blank
screen is the tricky part.

I had a look at NT's "Window Stations and Desktops" management
functions, but they only allow the visible desktop to be interactive,
all other stations/desktops are invisible and non-interactive. So it is
probably neccessary to write a special video driver to deal with the
issue.

A device dependant way of doing it would be to do something like on a
laptop and switch from the LCD screen to an external monitor. WinVNC
would allow you to see everything that the person infront of the
computer wouldn't be seeing on their non-existant external monitor. OR
If you are not using all the memory from your video card then you could
make it write to one area of memory and display from another. BOTH
involve using some special hardware feature of the video card.

Otherwise I think you would have to write a video {filter?} driver. Then
you could emulate your own video card in software {perhaps as a 'special
mode' of the exisiting video card}. WinVNC would have to 'switch' to
this driver {or activate the 'special mode'} as the need arises. The
emulation would act as a video card without passing or retrieving
information from the physical video card.

In both cases I don't see a way around looking into NT's DDK. But it
sounds HARD.

Keith.

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