.\" @(#)$Id: slocal.rf,v 1.15 1992/10/28 16:53:03 jromine Exp $
slocal \- special local mail delivery
@(MHETCPATH)/slocal \%[address\ info\ sender]
\%[\-addr\ address]
\%[\-info\ data]
\%[\-sender\ sender]
\%[\-user\ username]
\%[\-mailbox\ mbox]
\%[\-file\ file]
.\" \%[\-home\ homedir]
\%[\-maildelivery\ deliveryfile]
\%[\-verbose] \%[\-noverbose]
\fISlocal\fP is a program designed to allow you to have
your inbound mail processed according to a complex
set of selection criteria.
You do not normally invoke \fIslocal\fP yourself,
rather \fIslocal\fP is invoked on your behalf by your system's 
Message Transfer Agent.

The message selection
criteria used by \fIslocal\fP
is specified in the file \fI\&.maildelivery\fP
in the user's home directory.  The format of this file
is given below.

The message delivery address and message sender are
determined from the Message Transfer Agent
envelope information, if possible.  Under \fISendMail\fP,
the sender will obtained from the UUCP \*(lqFrom\ \*(rq
line, if present.  The user may override these values
with command line arguments, or arguments to 
the `\-addr' and `\-sender' switches.

The message is normally read from the standard input.
The `\-file' switch sets the name of the file from which
the message should be read, instead of reading stdin.
The `\-user' switch tells \fIslocal\fP
the name of the user for whom it is delivering mail.
The `\-mailbox' switch tells \fIslocal\fP the name
of the user's maildrop file.

The `\-info' switch may be used to pass an arbitrary
argument to sub-processes which \fIslocal\fP may
invoke on your behalf.
The `\-verbose' switch causes \fIslocal\fP
to give information on stdout about its progress.
The `\-debug' switch produces more verbose debugging output on stderr.

.Uh "Message Transfer Agents"
If your MTA is \fISendMail\fP,
you should include the line
.in +.5i
    \*(lq|\ @(MHETCPATH)/slocal\ \-user\ username\*(rq
.in -.5i
in your \&.forward file in your home directory.
This will cause \fISendMail\fP to invoke \fIslocal\fP on your behalf.

If your MTA is \fIMMDF-I\fP,
you should (symbolically) link @(MHETCPATH)/slocal to the file
bin/rcvmail in your home directory.
This will cause \fIMMDF-I\fP to invoke \fIslocal\fP on your behalf
with the correct \*(lq\fIaddress\ info\ sender\fP\*(rq arguments.

If your MTA is \fIMMDF-II\fP,
then you should not use \fIslocal\fP.
An equivalent functionality is already provided by \fIMMDF-II\fP;
see maildelivery(5) for details.

.Uh "The Maildelivery File"

The \fI\&.maildelivery\fR file
controls how local delivery is performed.
Each line of this file
consists of five fields, separated by white-space or comma.
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 backslash.
Lines beginning with `#' are ignored.
The format of each line in the \fI\&.maildelivery\fR file is:

	\fBheader	pattern	action	result	string\fR
.in +.5i
.ti -.5i
The name of a header field that is to be searched for a pattern.
This is any field in the headers of the message that might be present.
The following special fields are also defined:
.in +1i
.ta +1i
.ti -1i
\fIsource\fR	the out-of-band sender information
.ti -1i
\fIaddr\fR	the address that was used to cause delivery to the recipient
.ti -1i
\fIdefault\fR	this matches \fIonly\fR if the message hasn't been delivered yet
.ti -1i
\fI*\fR	this always matches
.in -1i

.ti -.5i
The sequence
of characters to match in the specified header field.
Matching is case-insensitive, but does not use regular expressions.

.ti -.5i
The action to take to deliver the message:
.in +1i
.ta +1i
.ti -1i
\fIdestroy\fR	This action always succeeds.

.ti -1i
\fIfile\fR or >	Append
the message to the file named by \fBstring\fR.
The message is appended to the file in the maildrop 
format which is used by your message transport system.
If the message can be appended to the file,
then this action succeeds.
When writing to the file,
a \*(lqDelivery\-Date:\ date\*(rq header is added
which indicates the date and time that message was appended to the file.

.ti -1i
\fImbox\fR	Identical
to \fIfile\fR,
but always appends the message using the format used by \fIpackf\fR
(the MMDF mailbox format).

.ti -1i
\fIpipe\fR or |	Pipe
the message as the standard input to the command named by \fBstring\fR,
using the Bourne shell \fIsh\fR(1) to interpret the string.
Prior to giving the string to the shell,
it is expanded with the following built-in variables:
.in +1i
.ta +1i
.ti -1i
$(sender) 	the out-of-band sender information
.ti -1i
$(address) 	the address that was used to cause delivery to the recipient
.ti -1i
$(size)	the size of the message in bytes
.ti -1i
$(reply\-to) 	either the \*(lqReply\-To:\*(rq or \*(lqFrom:\*(rq field
of the message
.ti -1i
$(info)	the out-of-band information specified
.in -1i
.ti -1i
\fIqpipe\fR or
.ti -1i
\fI<caret>\fR	Similar to \fIpipe\fR,
but executes the command directly,
after built-in variable expansion,
without assistance from the shell.
This action can be used to avoid quoting special characters
which your shell might interpret.
.in -1i

.ti -.5i
Indicates how the action should be performed:

.in +1i
.ta +1i
.ti -1i
\fIA\fR	Perform the action.
If the action succeeds, then the message is considered delivered.

.ti -1i
\fIR\fR	Perform the action.
Regardless of the outcome of the action,
the message is not considered delivered.

.ti -1i
\fI?\fR	Perform
the action only if the message has not been delivered.
If the action succeeds, then the message is considered delivered.

.ti -1i
\fIN\fR	Perform
the action only if the message has not been delivered
and the previous action succeeded.
If this action succeeds, then the message is considered delivered.
.in -1i
.in -.5i
To summarize, here's an example:
.if t .in +.5i
.ta \w'default  'u +\w'mh-workersxx 'uC +\w'destroy 'uC +\w'result 'u
#\fIfield\fR	\fIpattern\fR	\fIaction\fR	\fIresult\fR	\fIstring\fR
# lines starting with a '#' are ignored, as are blank lines
# file mail with mmdf2 in the \*(lqTo:\*(rq line into file mmdf2.log
\fITo	mmdf2	file	A	mmdf2.log\fP
# Messages from mmdf pipe to the program err-message-archive
\fIFrom	mmdf	pipe	A	/bin/err-message-archive\fP
# Anything with the \*(lqSender:\*(rq address \*(lqmh-workers\*(rq
# file in mh.log if not filed already
\fISender	mh-workers	file	?	mh.log\fP
# \*(lqTo:\*(rq unix \- put in file unix-news
\fITo	Unix	>	A	unix-news\fP
.\" # if the address is jpo=mmdf \- pipe into mmdf-redist
.\" \fIaddr	jpo=mmdf	|	A	mmdf-redist\fP
# if the address is jpo=ack \- send an acknowledgement copy back
\fIaddr	jpo=ack	\fP|\fI	R	\*(lq/bin/resend\0\-r\0$(reply-to)\*(rq\fP
# anything from steve \- destroy!
\fIFrom	steve	destroy	A	\-\fP
# anything not matched yet \- put into mailbox
\fIdefault	\-	>	?	mailbox\fP
# always run rcvtty
\fI*	\-	\fP|\fI	R	/mh/lib/rcvtty\fP
.if t .in -.5i

The file is always read completely,
so that several matches can be made and several actions can be taken.
The \fI\&.maildelivery\fR file must be owned either by the user or by root,
and must be writable only by the owner.
If the \fI\&.maildelivery\fR file cannot be found,
or does not perform an action which delivers the message,
then the file @(MHETCPATH)/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 perform an action which delivers the message,
then standard delivery to the user's maildrop is performed.

.Uh "Sub-process environment"
When a process is invoked, its environment is:
the user/group-ids are set to recipient's ids;
the working directory is the recipient's home 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 envariables \fB$USER\fR, \fB$HOME\fR, \fB$SHELL\fR are set
and no other envariables exist.

The process is given a certain amount of time to execute.
If the process does not exit within this limit,
the process will be terminated with extreme prejudice.
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 in determining the success of the
An exit status of zero means that the action succeeded.
Any other exit status (or abnormal termination) means that the action failed.

In order to avoid any time limitations,
you might implement a process that began by \fIforking\fR.
The parent would return the appropriate value immediately,
and the child could continue on,
doing whatever it wanted for as long as it wanted.
This approach is somewhat risky if the parent is going to return an
exit status of zero.
If the parent is going to return a non-zero exit status,
then this approach can lead to quicker delivery into your maildrop.

.Uh "Duplicate Message Suppression"
\fIslocal\fR is able to detect and supress duplicate messages.
To enable this,
create two empty files in your $HOME directory:
\&.maildelivery.pag and \&.maildelivery.dir.
These are ndbm files which are used to store the Message-IDs of
incoming messages.
^@(MHETCPATH)/mtstailor~^MH tailor file
^$HOME/\&.maildelivery~^The file controlling local delivery
^@(MHETCPATH)/maildelivery~^Rather than the standard file
^@(MHDROPLOC)~^The default maildrop
rcvstore(1), mhook(1), mh\-format(5)
, maildelivery(5)
`\-maildelivery \&.maildelivery'
`\-mailbox @(MHDROPLOC)'
`\-file' defaults to stdin
`\-user' defaults to the current user
For compatibility with older versions of \fIMH\fR,
if \fIslocal\fR can't find the user's \fI\&.maildelivery\fR file,
it will attempt to execute an old-style rcvmail hook in the user's $HOME
In particular,
it will first attempt to execute

.ti +.5i
\&.mh\(rureceive file maildrop directory user

failing that it will attempt to execute

.ti +.5i
$HOME/bin/rcvmail user file sender

before giving up and writing 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

\fISlocal\fP is designed to be backward-compatible with the
\fImaildelivery\fP facility provided by \fIMMDF-II\fP.
Thus, the \fI\&.maildelivery\fP file syntax is limited,
as is the functionality of \fIslocal\fP.

In addition to an exit status of zero,
the \fIMMDF\fR values \fIRP_MOK\fR (32) and \fIRP_OK\fR (9)
mean that the message has been fully delivered.
Any other non-zero exit status,
including abnormal termination,
is interpreted as the \fIMMDF\fR value \fIRP_MECH\fR (200),
which means \*(lquse an alternate route\*(rq
(deliver the message to the maildrop).
Only two return codes are meaningful, others should be.

\fISlocal\fP is designed to be
backwards-compatible with the \fImaildelivery\fP functionality provided
by \fBMMDF-II\fP.

Versions of \fIMMDF\fR with the \fImaildelivery\fR mechanism aren't
entirely backwards-compatible with earlier versions of \fIMMDF\fP.
If you have an \fIMMDF-I\fP old-style hook,
the best you can do is to have a one-line
\fI\&.maildelivery\fR file:

.ti +.5i
default \- pipe A \*(lqbin/rcvmail $(address) $(info) $(sender)\*(rq