Req #69175 [NEW]: posix_strerror is not thread-safe
From: james at jamesreno dot com
Operating system: Linux
PHP version: 5.6.6
Package: POSIX related
Bug Type: Feature/Change Request
Bug description:posix_strerror is not thread-safe
Description:
------------
As with alot of the PHP extensions some are not thread-safe by nature
however posix_strerror could easily be thread-safe by making a small
change to the way it operates and as such is fully capable of becoming
thread-safe. It is my impression that this use is not thread-safe (I
could be wrong).
The problem is that posix_strerror makes a call to strerror() which
returns a pointer to the string which may *not* be modified as it is
reused and overwritten by the next call to strerror. Instead
posix_strerror should call strerror_r which accepts a buffer and buffer
length and writes the data there instead.
Granted that PHP seems to be making a copy of the output for its own use
there is a possibility of a race condition occurring with other threads.
This is just a small potential improvement that shouldnt take much time
to implement and would be a a step forward for thread-safety.
There may be other cases of thread-safety issues in the posix extension
but those can be tackled one at a time. This is just a very limited and
specific report for one use case. If someone wants to scan the entire
extension for said issues more power to them but I am just requesting
this particular case be resolved.
Test script:
---------------
<?php
echo posix_strerror(110);
?>
Expected result:
----------------
No corruption should ever be possible to occur.
Actual result:
--------------
Corruption could possibly occur in a build utilizing multiple threads.
--
Edit bug report at https://bugs.php.net/bug.php?id=69175&edit=1
--
Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=69175&r=trysnapshot54
Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=69175&r=trysnapshot55
Try a snapshot (trunk): https://bugs.php.net/fix.php?id=69175&r=trysnapshottrunk
Fixed in SVN: https://bugs.php.net/fix.php?id=69175&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=69175&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=69175&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=69175&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=69175&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=69175&r=support
Expected behavior: https://bugs.php.net/fix.php?id=69175&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=69175&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=69175&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=69175&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=69175&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=69175&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=69175&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=69175&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=69175&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=69175&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=69175&r=mysqlcfg
Thread (2 messages)
- james at jamesreno dot com