<?php



function _commonPath($dirList)
{
	$arr = array();
	foreach($dirList as $i => $path)
	{
		$dirList[$i]	= explode('/', $path);
		unset($dirList[$i][0]);

		$arr[$i] = count($dirList[$i]);
	}

	$min = min($arr);

	for($i = 0; $i < count($dirList); $i++)
	{
		while(count($dirList[$i]) > $min)
		{
			array_pop($dirList[$i]);
		}

		$dirList[$i] = '/' . implode('/' , $dirList[$i]);
	}

	$dirList = array_unique($dirList);
	while(count($dirList) !== 1)
	{
		$dirList = array_map('dirname', $dirList);
		$dirList = array_unique($dirList);
	}
	reset($dirList);

	return current($dirList);
}

 

$dirs = array(
 '/home/user1/tmp/coverage/test',
 '/home/user1/tmp/covert/operator',
 '/home/user1/tmp/coven/members',
);


if('/home/user1/tmp' !== common_path($dirs))
{
  echo 'test fail';
} else {
  echo 'test success';
}

?>