fileowner

<?php         if (function_exists('posix_getpwuid') && function_exists('posix_geteuid')) {

            $composeUser = posix_getpwuid(posix_geteuid());

            $homeOwner = posix_getpwuid(fileowner($home));

            if (isset($composeUser['name'], $homeOwner['name']) && $composeUser['name'] !== $homeOwner['name']) {

                $io->writeError('<warning>You are running Composer as "'.$composeUser['name'].'", while "'.$home.'" is owned by "'.$homeOwner['name'].'"</warning>');

            }