Translate keysyms to ASCII

[Jeff Haran]

From: kernelnewbies-bounces at kernelnewbies.org [mailto:kernelnewbies-bounces at kernelnewbies.org] On Behalf Of Gabriel Duarte
Sent: Thursday, March 29, 2012 4:14 AM
To: kernelnewbies at kernelnewbies.org
Subject: Translate keysyms to ASCII

Hello people,


I working on a small proof of concept keylogger that works on kernel mode. It's parte of my studies of kernel development. 
I'm using the struct "keyboard_notifier_param" to get the keys pressed on the keyboard(s) attached to the system.

At the end, I print the value, like this:

printk(KERN_DEBUG "KEY== %i", param->value);


According to the definition of the struct "keyboard_notifier_param" at http://lxr.free-electrons.com/source/include/linux/keyboard.h#L37, the field value is a  "keycode, unicode value or keysym".

For example, when I press the key a, I get the value 30, but I would like tranlate it to the ASCII. I managed to create a translation table by myself, but I think there is another way more stylish to do this, or not? I googled a lot but could not find a consistent answer.

Any help is appreciated,

Gabriel.

-- 
Gabriel Duarte
Linux User #471185
France / Grenoble - Rhône Alpes
http://genericdev.wordpress.com/

The term I think you want to search for is "PC keyboard scan code". This link seems to cover it pretty well:

http://www.quadibloc.com/comp/scan.htm

Jeff Haran