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slocal(1)							    slocal(1)



NAME

  slocal - MH receive-mail hooks

SYNOPSIS

  slocal $HOME/.maildelivery [-form formfile] [switches	for postproc]
  address... [-help]

  /usr/lib/mh/rcvpack file [-help]

  /usr/lib/mh/rcvtty [command...] [-help]

DESCRIPTION

  A receive-mail hook is a program that	is run whenever	you receive a mail
  message. You do not invoke the hook yourself;	it is invoked on your behalf
  by sendmail, when you	include	the following line in your .forward file in
  your home directory:

       "| /usr/lib/mh/slocal -user username"

  The .maildelivery file, which	is an ordinary ASCII file, controls how	local
  delivery is performed. This file is read by slocal.

  The format of	each line in the .maildelivery file is:

       field pattern action result string

  These	components are explained below:

  field:
      The name of a field that is to be	searched for a pattern.	 This is any
      field in the headers of the message that might be	present. In addition,
      the following special fields are also defined:

      source: the out-of-band sender information

      addr: the	address	that was used to cause delivery	to the recipient

      default: this matches only if the	message	has not	been delivered yet

      *: this always matches

  pattern:
      The sequence of characters to match in the specified field.  Matching
      is case-insensitive but not Regular Expression-based.

  action:
      The action to take to deliver the	message. This is one of	the follow-
      ing:

      file or >:
	  Append the message to	the file named by string using the standard
	  maildrop delivery process. If	the message can	be appended to the
	  file,	then this action succeeds. When	writing	to the file, a new
	  field	is added:

	  Delivery-Date: <date>
	      This field indicates the date and	time at	which the message was
	      appended to the file.

      pipe or |	:
	  Pipe the message as the standard input to the	command	named by
	  string. The Bourne shell, sh(1), is used to interpret	the string.
	  Prior	to giving the string to	the shell, it is expanded with the
	  following built-in variables:

	  $(sender): the return	address	for the	message

	  $(address): the address that was used	to cause delivery to the
	  recipient

	  $(size): the size of the message in bytes

	  $(reply-to): either the Reply-To: or From: field of the message

	  $(info): miscellaneous out-of-band information

	  When a process is invoked, its environment is	as follows: the
	  user/group id's are set to recipient's id's; the working directory
	  is the recipient's directory;	the umask is 0077; the process has no
	  /dev/tty; the	standard input is set to the message; the standard
	  output and diagnostic	output are set to /dev/null; all other file-
	  descriptors are closed; the environment variables $USER, $HOME, and
	  $SHELL are set appropriately;	no other environment variables exist.

	  The process is given a certain amount	of time	to execute. If the
	  process does not exit	within this limit, it is terminated. The
	  amount of time is calculated as ((size x 60) + 300) seconds, where
	  size is the number of	bytes in the message.

	  The exit status of the process is consulted to determine the suc-
	  cess of the action. An exit status of	0 means	that the action	suc-
	  ceeded. Any other exit status	(or abnormal termination) means	that
	  the action failed.

	  In order to avoid any	time limitations, you might implement a	pro-
	  cess that began by forking. The parent would return the appropriate
	  value	immediately, and the child could continue to do	whatever it
	  wanted for as	long as	it wanted.  This approach should only be used
	  if you do not	care about the outcome of the action, because the
	  success or failure of	the child process cannot be passed back	to
	  slocal. However, if the parent is going to return a non-zero exit
	  status, then this approach can lead to quicker delivery into your
	  maildrop.

      qpipe or ^ :
	  This is similar to pipe, but executes	the command directly, after
	  built-in variable expansion, without assistance from the shell.

      destroy:
	  This action always succeeds.

  result:
      Indicates	how the	action should be performed. The	following values are
      valid:

      A:  Perform the action. If the action succeeded, then the	message	is
	  considered delivered.

      R:  Perform the action. Regardless of the	outcome	of the action, the
	  message is not considered delivered.

      ?:  Perform the action only if the message has not been delivered.  If
	  the action succeeded,	then the message is considered delivered.

  The file is always read completely, so that several matches can be made and
  several actions can be taken.	The .maildelivery file must be owned either
  by the user or by root, and must be writable only by the owner. If the
  .maildelivery	file cannot be found, or does not perform an action which
  delivers the message,	then the file /usr/lib/mh/maildelivery is read
  according to the same	rules. This file must be owned by the root and must
  be writable only by the root.	If this	file cannot be found or	does not per-
  form an action which delivers	the message, then standard delivery to the
  user's maildrop, /usr/spool/mail/$USER, is performed.

  Arguments in the .maildelivery file are separated by a comma (,) or by
  white	space. Since double quotes are honored,	these characters may be
  included in a	single argument	by enclosing the entire	argument in double
  quotes ("). A	double quote can be included by	preceding it with a back-
  slash.

  Four programs	are currently available: rcvdist redistributes incoming	mes-
  sages	to additional recipients; rcvpack saves	incoming messages in a
  packf(1) file; and rcvtty notifies the user of incoming messages. The
  fourth program, rcvstore, is described in the	rcvstore(1) reference page.
  They all reside in the /usr/lib/mh directory.

  The rcvdist program resends a	copy of	the message to all of the addresses
  listed on its	command	line. It uses the format string	facility described in
  mh-format(4).

  The rcvpack program appends a	copy of	the message to the file	listed on its
  command line.	It is made obsolete by .maildelivery.

  The rcvtty program executes the named	file with the message as its standard
  input, and gives the resulting output	to the terminal	access daemon for
  display on your terminal. If the terminal access daemon is unavailable on
  your system, then rcvtty writes the output to	your terminal, only if your
  terminal has world-writable permission. If no	valid file is specified, then
  rcvtty gives a one-line scan listing to the terminal access daemon.

RESTRICTIONS

  For compatibility with older versions	of MH, if slocal cannot	find the
  user's .maildelivery file, it	attempts to execute an old-style rcvmail hook
  in the user's	$HOME directory. Specifically, it first	attempts to execute
  the command:

       .mh_receive file	maildrop directory user

  Failing that it attempts to execute:

       $HOME/bin/rcvmail user file sender

  If both of these fail, it gives up and write to the user's maildrop.

  In addition, whenever	a hook or process is invoked, file-descriptor three
  (3) is set to	the message in addition	to the standard	input.

  Only two return codes	are meaningful,	others should be.




EXAMPLES

  This section shows how slocal	could be used.


  In this example, line-by-line	comments have been extracted from the code to
  aid readability of the example. The line numbers would not normally be in
  the code; they are there to help you.	The code fragment precedes the expla-
  nation:

  ______________________________________________________________
	  field	    pattern    action	 result	  string


  ______________________________________________________________
  (1)	  To	    mmdf2      file	 A	  mmdf2.log
  (2)	  From	    mmdf       pipe	 A

						  err-message-
						  archive
  (3)	  Sender    uk-mmdf    file	 ?	  mmdf2.log
  (4)	  To	    Unix       >	 A	  unix-news
  (5)	  addr	    jpo=mmdf   |	 A	  mmdf-redist
  (6)	  addr	    jpo=ack    |	 R

						  resend -r
						  $(reply-to)
  (7)	  From	    steve      destroy	 A	  -
  (8)	  default   -	       >	 ?	  mailbox
  (9)	  *	    -	       |	 R	  rcvalert
  ______________________________________________________________

  Line 1:
      File mail	with mmdf2 in the To: line into	file mmdf2.log.

  Line 2:
      Messages from mmdf are piped to the program err-message-archive.

  Line 3:
      Take anything with the address uk-mmdf in	the Sender: field, and file
      it in mmdf2.log, if it has not already been filed	by line	1.

  Line 4:
      Put messages addressed to	Unix in	the file unix-news.

  Line 5:
      If the address is	jpo=mmdf, pipe the message into	mmdf-redist.

  Line 6:
      If the address is	jpo=ack, send an acknowledgement copy back.

  Line 7:
      Destroy anything from steve.

  Line 8:
      Take anything that is not	matched	yet and	put it into mailbox.

  Line 9:
      Always run rcvalert.

FILES

  /usr/lib/mh/mtstailor
      The system customization file.

  /usr/lib/mh/maildelivery
      The system default file controlling local	delivery.

  $HOME/.maildelivery
      The user-supplied	alternative to the system default file controlling
      local delivery.







SEE ALSO

  rcvstore(1)