From: agustin dot moyano at gmail dot com
Operating system: openSUSE 12.1 (x86_64)
PHP version: 5.4.6
Package: Semaphore related
Bug Type: Bug
Bug description:sem_acquire won't lock on forked environment
Description:
------------
The actual php version is
# php --version
PHP 5.5.0-dev (cli) (built: Aug 24 2012 16:34:36)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
php was configured with:
./configure --enable-sysvsem --enable-sysvshm --enable-pcntl
sem_acquire won't lock when a forked process acquires the semaphore. This
behaviour is the same whether sem_get is called in every process or before
the
first pcntl_fork.
It would seem sem_acquire treats forked processes as if they where the same
process as the father, even if the got different pid.
I also tryed this bug with
$ php --version
PHP 5.3.10-1ubuntu3.2 with Suhosin-Patch (cli) (built: Jun 13 2012
17:19:58)
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies
in
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.1 LTS
Release: 12.04
Codename: precise
whith exactly the same results. Thanks.
Test script:
---------------
<?php
$pid = pcntl_fork();
if ($pid == -1) {
die("could not fork 1");
} else if ($pid) {
$pid = pcntl_fork();
if ($pid == -1) {
die("could not fork 2");
} else if($pid) {
$sem = sem_get('1234');
echo "father try acquire $sem\n";
$time = microtime();
sem_acquire($sem);
echo "father acquired in ".($time-microtime())."\n";
} else {
$sem = sem_get('1234');
echo "son 2 try acquire $sem\n";
$time=microtime();
sem_acquire($sem);
echo "son 2 acquired in ".($time-microtime())."\n";
}
} else {
$sem = sem_get('1234');
echo "son 1 try acquire $sem\n";
$time=microtime();
sem_acquire($sem);
echo "son 1 acquired in ".($time-microtime())."\n";
}
?>
Expected result:
----------------
storage-tests:~ # php prueba.php
father try acquire Resource id #4
father acquired in -4.6999999999964E-5
son 2 try acquire Resource id #4
son 1 try acquire Resource id #4
Actual result:
--------------
storage-tests:~ # php prueba.php
father try acquire Resource id #4
father acquired in -4.6999999999964E-5
son 2 try acquire Resource id #4
son 1 try acquire Resource id #4
son 2 acquired in -0.00010599999999999
son 1 acquired in -0.00010499999999997
--
Edit bug report at https://bugs.php.net/bug.php?id=62928&edit=1
--
Try a snapshot (PHP 5.4):
https://bugs.php.net/fix.php?id=62928&r=trysnapshot54
Try a snapshot (PHP 5.3):
https://bugs.php.net/fix.php?id=62928&r=trysnapshot53
Try a snapshot (trunk):
https://bugs.php.net/fix.php?id=62928&r=trysnapshottrunk
Fixed in SVN:
https://bugs.php.net/fix.php?id=62928&r=fixed
Fixed in SVN and need be documented:
https://bugs.php.net/fix.php?id=62928&r=needdocs
Fixed in release:
https://bugs.php.net/fix.php?id=62928&r=alreadyfixed
Need backtrace:
https://bugs.php.net/fix.php?id=62928&r=needtrace
Need Reproduce Script:
https://bugs.php.net/fix.php?id=62928&r=needscript
Try newer version:
https://bugs.php.net/fix.php?id=62928&r=oldversion
Not developer issue:
https://bugs.php.net/fix.php?id=62928&r=support
Expected behavior:
https://bugs.php.net/fix.php?id=62928&r=notwrong
Not enough info:
https://bugs.php.net/fix.php?id=62928&r=notenoughinfo
Submitted twice:
https://bugs.php.net/fix.php?id=62928&r=submittedtwice
register_globals:
https://bugs.php.net/fix.php?id=62928&r=globals
PHP 4 support discontinued:
https://bugs.php.net/fix.php?id=62928&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=62928&r=dst
IIS Stability:
https://bugs.php.net/fix.php?id=62928&r=isapi
Install GNU Sed:
https://bugs.php.net/fix.php?id=62928&r=gnused
Floating point limitations:
https://bugs.php.net/fix.php?id=62928&r=float
No Zend Extensions:
https://bugs.php.net/fix.php?id=62928&r=nozend
MySQL Configuration Error:
https://bugs.php.net/fix.php?id=62928&r=mysqlcfg
