ID: 47376
User updated by: pahan at hubbitus dot spb dot su
Reported By: pahan at hubbitus dot spb dot su
Status: Bogus
Bug Type: PCRE related
Operating System: Linux
PHP Version: 5.3.0beta1
New Comment:
>Your pattern could be: /(@@ -[\d,]+ \+[\d,]+ @@\s)(?1)+/
Yes, it seems as workaround (for my current work I apply other
workaraund too). It has not similar stack problems?
Wuote from info by you link:
Unfortunately, the effect of running out of stack is often
SIGSEGV,
though sometimes a more explicit error message is given. You
can nor-
mally increase the limit on stack size by code such as this:
struct rlimit rlim;
getrlimit(RLIMIT_STACK, &rlim);
rlim.rlim_cur = 100*1024*1024;
setrlimit(RLIMIT_STACK, &rlim);
So, main question is - may you correctly handle this problem at all
(throw/catch exceptions, fire errors, warnings etc.)??
For example, code such:
echo preg_replace('/(@@ -[\d,]+ \+[\d,]+ @@\s){2,643}/s', '-some
data-', $text);
generate warning:
PHP Warning: preg_replace(): Compilation failed: regular expression is
too large at offset 33 in /home/pasha/pcre-php-bug/pcre_bug.php on line
14
and all ok - I can correctly handle this situation on my script.
In any case, on production server segmentation fault depended from
incoming data is very-very bad idea.
Previous Comments:
------------------------------------------------------------------------
[2009-02-13 10:10:45] [email protected]
It's a known PCRE issue, and is documented:
http://www.manpagez.com/man/3/pcrestack/
------------------------------------------------------------------------
[2009-02-13 10:01:29] [email protected]
Your pattern could be: /(@@ -[\d,]+ \+[\d,]+ @@\s)(?1)+/
------------------------------------------------------------------------
[2009-02-13 09:01:51] pahan at hubbitus dot spb dot su
Thank you for the links it was pretty usefully.
I'm read information on it. Very strange read PHP documentation like:
====QUOTE:http://ru.php.net/manual/en/pcre.configuration.php====
pcre.recursion_limit integer
PCRE's recursion limit. Please note that if you set this value to a
*high number you may consume all the available process stack and
eventually crash PHP* (due to reaching the stack size limit imposed by
the Operating System).
====/QUOTE====
Really you can't provide any runtime check and provide standard way to
handle errors (or warnings)???
So, this low level limitation may be in pcre, but crash of PHP is PHP
BUG in any case!
And, If you a interesting, I'm make more investigation on this theme:
On default OS limit:
$ ulimit -s
10240
example script behaves as:
//ini_set('pcre.recursion_limit', 9939);//Segmentation fault
//ini_set('pcre.recursion_limit', 9938);//Work
So, If I increase stack size on my system:
$ ulimit -s 65536
all work fine, as expected!!!
------------------------------------------------------------------------
[2009-02-13 00:53:14] [email protected]
It isn't a PHP bug.
See bug#33468, bug#39387.
Thanks.
------------------------------------------------------------------------
[2009-02-12 22:51:08] pahan at hubbitus dot spb dot su
Sorry, sorry. Off course line "$text = file();" in reproduce code
unnecessary. Please remove it.
------------------------------------------------------------------------
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the rest of the comments, please view the bug report online at
http://bugs.php.net/47376
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