MHOOK(1) [mh.6] MHOOK(1)
NAME
mhook - MH receive-mail hooks
SYNOPSIS
$HOME/.maildelivery
/usr/contrib/mh/lib/rcvdist [-form formfile]
[switches for postproc] address ... [-help]
/usr/contrib/mh/lib/rcvpack file [-help]
/usr/contrib/mh/lib/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 your-
self, rather the hook is invoked on your behalf by Send-
Mail, when you include the line
| /usr/contrib/mh/lib/slocal -user $USER
in your .forward file in your home directory.
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
where
field:
The name of a field that is to be searched for a pat-
tern. This is any field in the headers of the mes-
sage that might be present. In addition, the follow-
ing 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 hasn't
been delivered yet
*: this always matches
pattern:
The sequence of characters to match in the specified
field. Matching is case-insensitive but not
RE-based.
action:
The action to take to deliver the message. This is
one of
file or >:
Append the message to the file named by string.
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The standard maildrop delivery process is used.
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
which indicates the date and time that message
was appended to the file.
pipe or |:
Pipe the message as the standard input to the
command named by string, using the Bourne shell
sh (1) 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:
the user/group id:s are set to recipient's id:s;
the working directory is the recipient's direc-
tory; the umask is 0077; the process has no
/dev/tty; the standard input is set to the mes-
sage; the standard output and diagnostic output
are set to /dev/null; all other file-descriptors
are closed; the envariables $USER, $HOME, $SHELL
are set appropriately, 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 calcu-
lated 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 action. 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 forking.
The parent would return the appropriate value
immediately, and the child could continue on,
doing whatever it wanted for as long as it
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MHOOK(1) [mh.6] MHOOK(1)
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.
qpipe or <caret>:
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:
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 can not be found, or does not perform
an action which delivers the message, then the file
/usr/contrib/mh/lib/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 can not be
found or does not perform an action which delivers the
message, then standard delivery to the user's maildrop,
/var/mail/$USER, is performed.
Arguments in the .maildelivery file are 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 dou-
ble-quote can be included by preceeding it with a back-
slash.
To summarize, here's an example:
#field pattern action result string
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MHOOK(1) [mh.6] MHOOK(1)
# lines starting with a '#' are ignored, as are blank lines
#
# file mail with mmdf2 in the To: line into file mmdf2.log
To mmdf2 file A mmdf2.log
# Messages from mmdf pipe to the program err-message-archive
From mmdf pipe A err-message-archive
# Anything with the Sender: address uk-mmdf-workers
# file in mmdf2.log if not filed already
Sender uk-mmdf-workers file ? mmdf2.log
# To: unix - put in file unix-news
To Unix > A unix-news
# if the address is jpo=mmdf - pipe into mmdf-redist
addr jpo=mmdf | A mmdf-redist
# if the address is jpo=ack - send an acknowledgement copy back
addr jpo=ack | R resend -r $(reply-to)
# anything from steve - destroy!
From steve destroy A -
# anything not matched yet - put into mailbox
default - > ? mailbox
# always run rcvalert
* - | R rcvalert
Four programs are currently standardly available, rcvdist
(redistribute incoming messages to additional recipients),
rcvpack (save incoming messages in a packf'd file), and
rcvtty (notify user of incoming messages). The fourth
program, rcvstore (1) is described separately. They all
reside in the /usr/contrib/mh/lib/ directory.
The rcvdist program will resend 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 (5).
The rcvpack program will append a copy of the message to
the file listed on its command line. Its use is obsoleted
by the .maildelivery.
The rcvtty program executes the named file with the mes-
sage as its standard input, and gives the resulting output
to the terminal access daemon for display on your termi-
nal. If the terminal access daemon is unavailable on your
system, then rcvtty will write the output to your terminal
if, and only if, your terminal has world-writable permis-
sion. If no file is specified, or is bogus, etc., then
the rcvtty program will give a one-line scan listing to
the terminal access daemon.
FILES
/usr/contrib/mh/lib/mtstailor tailor file
$HOME/.maildelivery The file controlling local delivery
/usr/contrib/mh/lib/maildelivery Rather than the standard file
SEE ALSO
rcvstore (1)
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MHOOK(1) [mh.6] MHOOK(1)
CONTEXT
None
HISTORY
For compatibility with older versions of MH, if slocal
can't find the user's .maildelivery file, it will attempt
to execute an old-style rcvmail hook in the user's $HOME
directory. In particular, it will first attempt to exe-
cute
.mh_receive file maildrop directory user
failing that it will attempt to execute
$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 addi-
tion to the standard input.
BUGS
Only two return codes are meaningful, others should be.
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