Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:12326
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Reply-To: ilia@prohost.org
To: internals@lists.php.net,
 Jason <jase303@yahoo.com>
Date: Tue, 24 Aug 2004 11:53:56 -0400
User-Agent: KMail/1.6.1
References: <20040824122859.1826.qmail@web11002.mail.yahoo.com>
In-Reply-To: <20040824122859.1826.qmail@web11002.mail.yahoo.com>
Organization: Prohost.org
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-ID: <200408241153.56659.ilia@prohost.org>
Subject: Re: [PHP-DEV] preg leak
From: ilia@prohost.org (Ilia Alshanetsky)

This is not a bug, but rather expected behavior. PCRE extension caches 
compiled regular expressions so that subsequent runs of the same regex do not 
need to perform the compilation step. In your example you are generating new 
regex in an unterminated loop, so it's no surprise that PHP eventually 
exhausts the available memory and terminates.

Ilia

On August 24, 2004 08:28 am, Jason wrote:
> Hi guys,
>
> I'm looking for the maintainer of the preg_match
> function in PHP.  There appears to be a nasty leak in
> its most basic functionality, and being a very
> fundamental function of PHP (not to mention that my
> long running scripts use it a lot ;) I thought I'd try
> and go the direct route.  Sorry, I don't know C or I'd
> try to fix it myself!  Considering its nature I
> thought best to at least make a post to the list
> rather than it get lost in the bugs pile (the original
> (much less refined) report from someone else had been
> sitting a long time).
>
> <?
> while (1) {
> 	$body    = "any string";
> 	$rand    = "any different
> strings".mt_rand(0,mt_getrandmax());
> 	$pattern = "/$rand/";
> 	preg_match($pattern, $body, $match);
> }
> ?>
>
> http://bugs.php.net/bug.php?id=28513
>
> This leaks 50MB per second on my PHP5.0.0,5.0.1.  It
> is probably the similar bug reported in PHP4.  If you
> have any suggestions, please let me know!
>
> Sincere regards,
>
> Jason.
>
>
>
>
> _______________________________
> Do you Yahoo!?
> Win 1 of 4,000 free domain names from Yahoo! Enter now.
> http://promotions.yahoo.com/goldrush