если так
var_dump(curl_exec(curl_init("file:///etc/passwd")));
ответ
Warning: curl_init() [function.curl-init]: open_basedir restriction in effect. File(/etc/passwd) is not within the allowed path(s): (/var/www/ru:/usr/lib/php:/tmp) in /var/www/ru/1.php on line 2
Warning: curl_exec(): supplied argument is not a valid cURL handle resource in /var/www/ru/1.php on line 2
bool(false)