<?php
// $Id: returnpath.module,v 1.7 2008/08/29 08:41:21 deciphered Exp $

/**
 * @file
 * Resolve sendmail 'return-path' header in emails sent from server.
 *
 * This allows bounceback emails to be returned to the sender, rather
 * than the server which originally relayed the mail.
 *
 * @author: Mike Carter <www.ixis.co.uk/contact>
 */

/**
 * Implementation of hook_help().
 */
function returnpath_help($path, $arg) {
  switch ($arg) {
    case 'admin/modules#description':
      return t('Correctly passes a return-path: header when processing email.');
  }
}

/**
 * Replaces the default user_mail() and adds the sendmail -f command to the PHP mail() call.
 */
function drupal_mail_wrapper($message) {
  unset($messages['headers']['From']);

  $mimeheaders = array();
  foreach ($message['headers'] as $name => $value) {
    $mimeheaders[] = $name .': '. mime_header_encode($value);
  }

  // If no explicit Return-path set, use From header and add Return-Path.
  $return_path = empty($message['headers']['Return-Path'])
    ? $message['from']
    : $message['headers']['Return-Path'];

  return mail(
    $message['to'],
    mime_header_encode($message['subject']),
    // Note: e-mail uses CRLF for line-endings, but PHP's API requires LF.
    // They will appear correctly in the actual e-mail that is sent.
    str_replace("\r", '', $message['body']),
    // For headers, PHP's API suggests that we use CRLF normally,
    // but some MTAs incorrecly replace LF with CRLF. See #234403.
    join("\n", $mimeheaders),
    // Adds the sendmail -f command.
    "-f". $return_path
  );
}