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Mail Archives: djgpp/1998/08/14/18:02:34

From: "John M. Aldrich" <fighteer AT cs DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Okay, I have to ask this
Date: Fri, 14 Aug 1998 00:59:34 -0400
Organization: Two pounds of chaos and a pinch of salt.
Lines: 35
Message-ID: <35D3C436.8E59BE4F@cs.net>
References: <35C3BC96 DOT 8DBD2960 AT a DOT crl DOT com> <1998081323151900 DOT TAA05635 AT ladder01 DOT news DOT aol DOT com>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

JRRuper wrote:
> 
> If I wanted to reverse engineer my own stuff what would I need and how would i
> do it?
> just wondering..
> the learning never stops :)

Well, assuming that you have your program's executable or object code,
but somehow managed to totally lose the source code, the best
recommendation I would have would be to pray that you have a printout or
recent backup.  :-)  I have a little story about that myself; I had a
program which I was distributing for testing, and shortly thereafter my
hard drives went haywire in an upgrade.  Although the problem was
eventually resolved, I recovered my work by asking the people whom I'd
emailed my source code to send it back.

In the total absence of source code, you basically have two choices. 
One:  recreate the program from memory, or rewrite it from scratch. 
Two:  attempt to disassemble and decompile the code.  While disassembly
is trivial (gdb can do it, for example), decompilation is a difficult
undertaking even if you know what language the source code was
originally written in.  If you stripped the debugging labels, it becomes
even more of a headache (from what I understand).  And even if all goes
perfectly, the very best you can expect to get is something that is
vaguely similar to what you wrote originally; you'll have to put in a
lot of work to restore the code.  Not impossible, but not worth the
effort unless it's your last resort.

-- 
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| John M. Aldrich, aka Fighteer I  |     mailto:fighteer AT cs DOT net     |
|      ICQ UIN#:  7406319          |   http://www.cs.net/fighteer/  |
|    ObJoke:  If Bill Gates were a robber, not only would he        |
|     shoot you, but he'd send you a bill for the bullets.          |
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