From: p at damezin dot com
Operating system: Linux
PHP version: 5.1.2
PHP Bug Type: Filesystem function related
Bug description: readfile() return old contents after a symlink() on the same
link...
Description:
------------
readfile() and file_get_contents() returns the old contents from an
internal php cache when a symlink is modified. Or it will return the
contents of an unlinked symlink().
This problem does not accured when realpath_cache_size is 0.
With php5 on apache2, the problem also exist from 1 page to another. (more
disturbing)
Reproduced on php 5.1.1 and 5.1.2 using Ubuntu or Gentoo Linux. Linux
Kernels 2.6.11, 2.6.15...
Reproduce code:
---------------
<?php
define('TEST_NUMBER', 2); // 1 ou 2
define('TEST_FILE1', 'testfile1');
define('TEST_FILE2', 'testfile2');
define('TEST_LINK', 'testlink');
// inexistant function in PHP4
if(!function_exists('file_put_contents')) {
function file_put_contents($file, $content) {
$fp = fopen($file,'w');
fputs($fp, $content);
fclose($fp);
}
}
file_put_contents(TEST_FILE1, 42);
file_put_contents(TEST_FILE2, 43);
// creating the TEST_LINK, using a temp. TEST_LINK NEEDED
$uid = uniqid(time());
symlink(TEST_FILE1, TEST_LINK . $uid);
rename(TEST_LINK . $uid, TEST_LINK);
// reading this file one time NEEDED
file_get_contents(TEST_LINK);
if(TEST_NUMBER === 1) {
unlink(TEST_LINK);
$good_result = '';
}
elseif(TEST_NUMBER === 2) {
$uid = uniqid(time());
symlink(TEST_FILE2, TEST_LINK . $uid);
rename(TEST_LINK . $uid, TEST_LINK);
$good_result = file_get_contents(TEST_FILE2);
}
// sleep(2);
// clearstatcache();
$result = @file_get_contents(TEST_LINK);
echo "TEST " . TEST_NUMBER . " : " . (($result == $good_result) ?
'SUCCEED' : 'FAILED') . "\n";
echo "result : [" . $result . "] | ";
echo "expected : [" . $good_result . "]\n";
echo "php version : " . PHP_VERSION."\n";
echo "realpath_cache_size (if available) : " .
@ini_get('realpath_cache_size') . "\n";
// cleaning
@unlink(TEST_LINK);
unlink(TEST_FILE1);
unlink(TEST_FILE2);
?>
Expected result:
----------------
dynphp2 root # php testcasephp.php
TEST 1 : SUCCEED
result : [] | expected : []
php version : 4.4.0
realpath_cache_size (if available) :
dynphp2 root # php testcasephp.php
TEST 2 : SUCCEED
result : [43] | expected : [43]
php version : 4.4.0
realpath_cache_size (if available) :
---
TEST 1 : SUCCEED
result : [] | expected : []
php version : 5.0.5
realpath_cache_size (if available) :
TEST 2 : SUCCEED
result : [43] | expected : [43]
php version : 5.0.5
realpath_cache_size (if available) :
Actual result:
--------------
lore ~ # php testcasephp.php
TEST 1 : FAILED
result : [42] | expected : []
php version : 5.1.2
realpath_cache_size (if available) : 16384
lore ~ # php testcasephp.php
TEST 2 : FAILED
result : [42] | expected : [43]
php version : 5.1.2
realpath_cache_size (if available) : 16384
---
TEST 1 : FAILED
result : [42] | expected : []
php version : 5.1.1-gentoo
realpath_cache_size (if available) : 16K
TEST 2 : FAILED
result : [42] | expected : [43]
php version : 5.1.1-gentoo
realpath_cache_size (if available) : 16K
--
Edit bug report at http://bugs.php.net/?id=36555&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=36555&r=trysnapshot44
Try a CVS snapshot (PHP 5.1):
http://bugs.php.net/fix.php?id=36555&r=trysnapshot51
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=36555&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=36555&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=36555&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=36555&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=36555&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=36555&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=36555&r=support
Expected behavior: http://bugs.php.net/fix.php?id=36555&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=36555&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=36555&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=36555&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=36555&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=36555&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=36555&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=36555&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=36555&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=36555&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=36555&r=mysqlcfg
