Simple mail + attachements

<?php
###############################
# Auteur: Atm0n3r
# Site: http://atmoner.com/
# Date: 16/09/2011
###############################
$b = 0;
$mail_attached = "";
$boundary = md5(time());
$fp = fopen($file_name,"rb");
$content[$b] = fread($fp,filesize($file_name));
$mail_attached .= "--" . $boundary . "\n"
. "Content-Type: binary/octet-stream; name=\"basename($file_name)\" \n"
. "Content-Transfer-Encoding: base64 \n"
. "Content-Disposition: inline; filename=\"basename($file_name)\" \n\n"
. chunk_split(base64_encode($content[$b]))." \n";
$b++;
fclose($fp);
$mail_attached .= "--".$boundary." \n";

$add_header = "MIME-Version: 1.0\n".
"Content-Type: multipart/mixed; boundary=\"$boundary\"; Message-ID: <".md5($email_from).">";
$mail_content = "--".$boundary."\n".
"Content-Type: text/plain; charset=\"UTF-8\"\n".
"Content-Transfer-Encoding: 8bit \n\n".
$msg." \n\n".
$mail_attached;
mail($email_address, $subject, $mail_content, "From: ".$email_from."\nCC: ".$email_cc."\n
BCC: ".$email_bcc ."\n Errors-To: ".$email_from."\n".$add_header);
?>