Re: c00l hack

Article: 7591 of alt.hackers
From: cjfred@clark.net (Chris Frederick)
Newsgroups: alt.hackers
Subject: Re: c00l hack
Date: 4 Apr 1995 00:58:26 -0400
Organization: Clark Internet Services, Ellicott City, MD
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Approved: abundy@shoestore.chicago.il.us
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In article <3lqcbn$h6h@case.cyberspace.com>,
Wes Santee <wsantee@cyberspace.com> wrote:

> Hmmmm, while we're on the data recovery motif, I remember when I had
> to talk a guy through a complete drive rebuild over the phone.

Ugh.  I do phone support at work, and holding the user's hand through
recovering a drive from scratch doesn't sound like much fun.

ObTechSupportHack:

A user reported that the print-screen capability of my company's Unix
software package didn't work in the online help utility.  The user urgently
needed to print out some help pages, so I looked at the source code and
discovered that a programmer had accidentally used '%d' rather than '%s'
in a sprintf() format string.  This caused the Unix "lp" command to
be called with a number instead of a filename as an argument.

Rather than rebuild the (rather large) program and upload it over a slow
modem connection, I hoped to patch the single byte in question.  I located
the offset of the byte in the executable via "strings", but the
computer had
no C compiler, which shot down my plan of using a program to simply seek to
the byte and overwrite it with a new one.  Instead, I used two "dd"
commands
to extract the data leading up to the byte and the data after the byte into
separate files, and then concatenated the two with the new byte in between.
The new executable worked like a charm.

--
It is hard to be religious when certain | Chris Frederick (cjfred@clark.net)
people fail to be incinerated by bolts  | FTP : ftp.clark.net:/pub/cjfred
of lightning.  -  Calvin                | URL : http://www.clark.net/pub/cjfred

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