» include(), MySQL-Cache und Race Conditions

<?php
error_reporting(E_ALL);
function mkfile($filename, $data='', $chmod=0644) {
	$h = fopen($filename, 'w');
	fwrite($h, $data);
	fclose($h);
	umask(0000);
	chmod($filename, $chmod);
	return $data;
}
$mysql_cache = '<?php $foo = 1; ?' . '>';
$strlen = strlen($mysql_cache);
for ($i = 0; $i < $strlen; $i++) {
	// we write our cache file char by char because in a
	// live environment it is possible that a second
	// request tries to include a partial file as the first
	// process isn't finished writing the file
	$filename = 'cache3/' . $i . '.php';
	if (file_exists($filename)) {
		unlink($filename);
		usleep(500000);
	}
	mkfile($filename, substr($mysql_cache, 0, $i));
	usleep(500000);
	include($filename);
}
echo "Done";
?>

    <<br />
    <b>Parse error</b>:  syntax error, unexpected end of file in <b>/usr/www/users/maxrep/cache3/3.php</b> on line <b>1</b><br />

<?php
// file was written completely
var_dump(unserialize('i:1;'));
// file partially written
var_dump(unserialize('i:1'));
var_dump(unserialize('i:'));
var_dump(unserialize('i'));
var_dump(unserialize(''));
?>

int(1)
bool(false)
bool(false)
bool(false)
bool(false)

Mach mit!