LockDis v. 1.0
A very simple X screen locker.  No flying toasters.
Copyright (C) 2009  Brett McNamara <brett@chaingang.org>
GPL 3


USE

Before you can use this program, you have to set your password.  
Simply invoke the program with -p, e.g. "lockdis -p", and you'll be 
asked to enter a password.  After that, when you invoke the program 
your screen will go blank.  Nothing will move, even the mouse pointer 
should disappear.  Hitting the keyboard will enter the first 
character of your password and some basic grayscale graphics will 
appear to let you know you're on the right track.  Hitting enter will 
either release you, if the password is correct, or blank the screen 
again and ignore you.  Escape will also blank the screen again.

If you forget your password, just make up another.


PASSWORD

Why don't you just use my already existing password like everyone 
else?

Most modern systems use "shadow" passwords.  While there is a 
standard library to validate against these, it's held back from most 
distros.  Also, in order to function correctly, it usually has to be 
run as root.  If you roll your own, you still need root.  For this 
reason many screen savers run as, ahem, root.  I didn't want this 
little program to run as root, at all.  Plus there are better 
password hashers out there now, most crypt still uses DES.  There are 
also some legal issues with passing encryption around the world.

LockDis uses SHA512.  It doesn't need your libraries, it's got it's 
own.  A verbatim copy of the one first released into the Public 
Domain by Ulrich Drepper.  Thanks Ulrich.


ABOUT

Blanking the screen and locking it with a password seems like such a 
simple thing.  There are lots of programs out there that do this and 
so much more.  Most are screen savers with little dancing lights and 
all the eye candy.  Sometimes eye candy is nice.  Sometimes it chews 
up CPU you'd rather be working elsewhere.  Worst case, the eye candy 
get's so happy that it takes over and even locks the machine.

I like GNOME, but gnome-screensaver has hurt me on more than one 
occasion.  It's more mature cousin, XScreenSaver, is also not without 
blame.   The problem isn't necessarily the fault of these frameworks, 
but perhas just one of the multitude of graphic programs they launch. 
 So, after another crash, I went looking for a program that would 
just blank my screen and ask for a password.  Shockingly, I found 
nothing to do this most basic task.

The nice thing about being a programmer is that if the problem annoys 
you enough, you can write your own solution.  This program is my 
solution to my problem.  It's short, simple, spartan, just a blank 
screen, please.  If other people have the same frustration, I hope 
they find this useful, too.


WHAT'S IN A NAME

LockDis is obviously short for lock display.  However, here in New 
Jersey it's also part the vernacular.  "This" and "that" are often 
enunciated "dis" and "dat."  So the name, while practical, is also a 
local homage.

