GNU bug report logs - #21611
probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#21611: closed (probable bug in tee: tee overwrites argv[argc]
 (coreutils-8.24))
Date: Sun, 04 Oct 2015 00:07:03 +0000

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Your message dated Sat, 3 Oct 2015 17:06:52 -0700
with message-id <56106D9C.4080400 <at> cs.ucla.edu>
and subject line Re: bug#21611: probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)
has caused the debbugs.gnu.org bug report #21611,
regarding probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


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From: Rainer Deyke <rainerd <at> eldwood.com>
To: bug-coreutils <at> gnu.org
Subject: probable bug in tee: tee overwrites argv[argc] (coreutils-8.24)
Date: Sat, 3 Oct 2015 11:48:59 +0200

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As mentioned in a comment on line 198 of 'tee.c', 'tee' overwrites 
'argv[argc]'.  This is very bad style at best, and probably undefined 
behavior on at least some platforms.  The attached patch replaces the 
current hack with another hack that is still bad style, but probably 
safer than the current hack.


-- 
Rainer Deyke (rainerd <at> eldwood.com)

[patch (text/plain, attachment)]

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From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Rainer Deyke <rainerd <at> eldwood.com>, 21611-done <at> debbugs.gnu.org
Subject: Re: bug#21611: probable bug in tee: tee overwrites argv[argc]
 (coreutils-8.24)
Date: Sat, 3 Oct 2015 17:06:52 -0700

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Rainer Deyke wrote:
> As mentioned in a comment on line 198 of 'tee.c', 'tee' overwrites
> 'argv[argc]'.  This is very bad style at best, and probably undefined behavior
> on at least some platforms.

Thanks for the report.  It's well-defined behavior on any platform conforming to 
the C standard, so it should be quite safe.  That being said, it's a bit faster 
to subtract 1 from a pointer than to do the equivalent of a memmove of an array, 
so it sounds a bit faster to do things the way you suggest.  Cleaner, too.  I 
installed the attached patch.

[0001-tee-simplify-argv-handling.patch (text/plain, attachment)]

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