 |
| Copyright © 1997Mark Russinovich |
Last Updated July 9, 1997
|
| Introduction |
Ctrl2cap
is a kernel-mode device driver that filters the system's
keyboard class driver in order to convert caps-lock
characters into control characters. People like myself
that migrated to NT from UNIX are used to having the
control key located where the caps-lock key is on the
standard PC keyboard, so a utility like this is essential
for our editing well-being. The primary purpose
of this driver is not serve as a caps-lock to control
mapping utility, but rather to demonstrate how system
keyboard input can be caught and manipulated before NT
even "sees" it. At this level it is even
possible to filter out the ctrl-alt-del combination (why
you would want to do that is beyond me, given that
administrative support exists to provide the same
end-effect, but whatever…).
|
| Installation and
Use |
Install
Ctrl2cap by first copying ctrl2cap.sys to your
SystemRoot\system32\drivers driectory. If you are running
on NT 4.0, type "regedit ctrl2cap.reg" and
reboot. If you are running on NT 3.51, create by hand the
registry key specified in ctrl2cap.reg, along with the
indicated values. |
| Building
Ctrl2cap |
Ctrl2cap
requires ntddkbd.h from the ddk\src\input\inc directory,
so you must first copy that file to the ctrl2cap
directory. Then build with the standard tools. Ctrl2cap
also demonstrates the use of the function
HalDisplayString(), which can be used either to throw a
custom blue-screen, or to print messages to the blue
screen that is present during system initialization.
Ctrl2cap prints a message that it has initialized at
System-Start time. |
How Ctrl2cap
Works
|
Ctrlcap
is actually quite trivial. It simply attaches itself to
the keyboard class driver so that it will catch keyboard
read requests. For each request, it posts an I/O
completion callback, at which point it takes a peek at
the scancode that is being returned. If it happens to be
a caps-lock, ctrl2cap changes it into a left-control. |
More Information
|
For more
information on writing filter drivers (drivers that
attach themselves to other drivers so that they can see
their input and/or output), here are sources to check
out: The Windows NT DDK sample
\src\storage\filter\diskperf "Examining the Windows
NT File System," by Mark Russinovich and Bryce
Cogswell, Dr. Dobb's Journal, February 1997, and the
accompanying file system filter driver, NTFilemon.
|
Download Ctrl2cap Plus Source (6KB)
|
 |