Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!mcsun!sunic!draken!d88-eli
From: d88-eli@nada.kth.se (Erik Liljencrantz)
Newsgroups: comp.lang.pascal
Subject: Re: disable ^C in Turbo Pascal
Message-ID: <2942@draken.nada.kth.se>
Date: 14 Feb 90 07:08:14 GMT
References: <116500002@uxa.cso.uiuc.edu>
Reply-To: d88-eli@nada.kth.se (Erik Liljencrantz)
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 28

In article <116500002@uxa.cso.uiuc.edu> bcs33424@uxa.cso.uiuc.edu writes:
>	I'm writing a password program in Turbo Pascal for friend's
>    computer.  The program is fine, but I can't disable control-C.
>    I've tried the break command under DOS, and the {C-}, {C+},      
>    {$U-}, and the {$U+} (the book I'm using is very vague).  With-
>    out the control-C disabled, the program has no real effect.
>    Is there something I missed?  Is there another compiler directive 
>    I could use?  Could the autoexec.bat be written so that, if
>    the password program is stopped by a ^C that it recalls the
>    password program, until it is ended normally?  

  It's always possible to break AUTOEXEC.BAT and MS-DOS asks if you want
to terminate the batch-file. The only possibility is to do something before
the execution of AUTOEXEC.BAT begins, that is in CONFIG.SYS: Write a device-
driver!

  The line DEVICE=device.sys in CONFIG.SYS loads a devicedriver and calls the
initialization code in the driver. That code could display a password prompt,
and refuse any CTRL-C or incorrect password.

  However, a devicedriver requires some (understatement...) assembly
programming. And another thing: You can't protect the system from floppy boot.
Anyone with a bootable floppy can enter the system...

  I've written a devicedriver (XTRALOCK.SYS). I can mail it to you (and others)
if you are interested (it includes assembly source).
-- 
Erik Liljencrantz     | "No silly quotes!!"
d88-eli@nada.kth.se   |  Embraquel D. Tuta