 A WWW FORMs to Mail gateway

 Copyright (c) 10.6.94 by Andreas Ley <ley@rz.uni-karlsruhe.de>

 Permission to use, copy, modify, and distribute this software for any
 purpose and without fee is hereby granted, provided that the above
 copyright notice appears in all copies. This software is provided "as is"
 and without any express or implied warranties.

 Usage:

     - Since WWW is anonymous, mail sent through the WWW Mail Gateway
       is anonymous, too. Some people don't like to get anonymous mail,
       that's why mailto can be used with an access configuration file,
       which specifies who is enabled to get mail through the WWW Mail
       Gateway. If you don't need access control, just undefine ADDRESSES,
       otherwise point it to a configuration file with entries:
	       <address> (<realname>)
       <realname> is optional.

     - Calling /cgi-bin/mailto/<address>/<subject>/<url> gives you a template
       mail FORM. <address> is the recipients email address, <subject> is
       a predefined subject and <url> is the URL of an acknowledgement page.
       Any of the parameters may be skipped; since address and subject
       are required, mailto will generate input fields if they're
       missing.

       You may also call it from within a simple shell and you'll get
       an example as well.

     - Create your own customized/beautified FORM with METHOD=POST and
       ACTION=/cgi-bin/mailto/<address>/<subject>/<url>. As above, <address>
       is the recipients email address, <subject> is a predefined subject and
       <url> is the URL of an acknowledgement page. You can replace any of
       these parameters by INPUTs with NAME= "To", "Subject" or "Acknowledge"
       respectively, which may also be of TYPE=hidden (recommended for the
       acknowledgement URL). These INPUTs will be treated special, as will
       be NAME="From" (NAME="Reply-To" provides the same functionality but
       is obsolete and it's use is discouraged) and NAME="Copy-Self". They
       all have precedence over the URL parameters. Use of the INPUTs is
       recommended.
       When the FORM is submitted, the <address> (or the VALUE of the
       NAME="To" field) will be checked against the configuration file, the
       contents will be converted into a mail message and the message will be
       sent to <address> (<realname>) with <subject> (or the VALUE of the
       NAME="Subject" field) as the subject. Input fields will be listed as
       "<name>: <content><LF>" for one-line-contents and as
       "<name>:<LF><content><LF><content><LF>.<LF>" for multi-line-contents
       with leading periods preceded by another period.
       If an INPUT with TYPE="checkbox" and NAME="Copy-Self" has been checked,
       a copy of the message will be sent to the originator of the message
       as specified in the NAME="From" (or NAME="Reply-To") field.
       If <url> (or a field with NAME="Acknowledge") was specified, it will
       be sent back as a confirmation to the sender.

     - Only addresses that are listed in /etc/mailto.conf are valid
       and will be delivered.

A common example would look like

       <form action="/cgi-bin/mailto/address" method=post>
       E-Mail    : <input name="Reply-To" size=44><p>
       Copy      : <input name="Cc" size=44><p>
       Blind Copy: <input name="Bcc" size=44><p>
       Self Copy : <input name="Copy-Self" size=44><p>
       Hotlink   : <input name="URL" size=55><br>

       <input type=hidden name="Acknowledge" value="/special/mailto-answer.html">
       <input type=hidden name="Subject" value="Test the mailto">

       <input type=submit value="Submit"> . <input type=reset value="Reset">
       </form>

Special variables
-----------------

The following variables have a special meaning when they are part of
the form data which is sent to the web server and eventually to the
CGI program mailto.  The field names are case sensitive.  They won't
end up in the mail body but will be used for constructing and
delivering the resulting mail.

  Acknowledge		Web page for redirection on success
  Subject		Subject of the sent  mail
  Reply-To | From	Submitter address, will be used as From: line
  Cc			Send a copy to, visible in the header
  Bcc			Send a copy to, invisible in the header
  Copy-Self		Send a blind copy to the submitter
  To			Recipient of the mail, should be submitted as .../address
