slocal.1mh

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH slocal 1mh
.SH Name
slocal \- MH receive-mail hooks
.SH Syntax
.B slocal
.B $HOME/\&.maildelivery
[
.B \-form
.I formfile
] [
.I "switches for"
.PN postproc
]
.I "address ..."
[
.B \-help
]
.PP
.B /usr/lib/mh/rcvpack
.I file
[
.B \-help
]
.PP
.B /usr/lib/mh/rcvtty 
[
.I "command ..."
] [
.B \-help
]
.\"
.\"
.\"
.\"
.SH Description
.NXR "slocal command"
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 
.PN sendmail ,
when you include the following line
in your 
.PN \&.forward 
file in your home directory:
.EX
| /usr/lib/mh/slocal \-user $USER
.EE
.PP
The 
.PN \&.maildelivery 
file,
which is an ordinary ASCII file,
controls how local delivery is performed.
This file is read by 
.PN slocal .
.PP
The format of each line in the 
.PN \&.maildelivery
file is:
.EX
field pattern action result string
.EE
.PP
These components are explained below:
.\"
.IP "field:" 10
The name of a field that is to be searched for a pattern.
This is any field in the headers of the message that might be present.
In addition, the following special fields are also defined:
.IP 
.IR source : 
the out-of-band sender information
.IP
.IR addr : 
the address that was used to cause delivery to the recipient
.IP
.IR default : 
this matches only if the message has not been delivered yet
.IP
.IR * :
this always matches
.\"
.\"
.IP "pattern:"
The sequence of characters to match in the specified field.
Matching is case-insensitive but not Regular Expression-based.
.\"
.\"
.IP "action:" 10
The action to take to deliver the message.
This is one of the following:
.\"
.IP " " 10
.I file
or
.IR > :
.IP 
Append the message to the file named by 
.B string 
using the standard maildrop delivery process.
If the message can be appended to the file,
then this action succeeds.
When writing to the file,
a new field is added:
.EX
Delivery-Date: <date>
.EE
This field indicates the date and time 
at which the message was appended to the file.
.\"
.IP " " 10
.I pipe
or | :
.IP 
Pipe the message as the standard input 
to the command named by 
.BR string .
The Bourne shell,
.MS sh 1 ,
is used to interpret the string.
Prior to giving the string to the shell,
it is expanded with the following built-in variables:
.IP
\f(CW$(sender)\fR: 
the return address for the message
.IP
\f(CW$(address)\fR: 
the address that was used to cause delivery to the recipient
.IP
\f(CW$(size)\fR: 
the size of the message in bytes
.IP
\f(CW$(reply-to)\fR: 
either the \f(CWReply-To:\fR or \f(CWFrom:\fR field of the message
.IP
\f(CW$(info)\fR: 
miscellaneous out-of-band information
.IP
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 
.PN /dev/tty ;
the standard input is set to the message;
the standard output and diagnostic output are set to 
.PN /dev/null ;
all other file-descriptors are closed;
the environment variables \f(CW$USER\fR, \f(CW$HOME\fR, 
and \f(CW$SHELL\fR are set appropriately;
no other environment variables exist.
.IP
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 \f(CW((size x 60) + 300)\fR seconds,
where size is the number of bytes in the message.
.IP
The exit status of the process is consulted 
to determine the success of the action.
An exit status of 0 means that the action succeeded.
Any other exit status (or abnormal termination) 
means that the action failed.
.IP
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 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
.PN 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.
.\"
.IP " " 10
.I qpipe
or
.I "^" 
:
.IP 
This is similar to 
.IR pipe ,
but executes the command directly,
after built-in variable expansion,
without assistance from the shell.
.\"
.IP " " 10
.IR destroy :
.IP 
This action always succeeds.
.IP "result:" 10
Indicates how the action should be performed.
The following values are valid:
.IP " " 10
.IR A :
.IP
Perform the action.
If the action succeeded, then the message is considered delivered.
.IP " " 10
.IR R :
.IP
Perform the action.
Regardless of the outcome of the action,
the message is not considered delivered.
.IP " " 10
.IR "?" :
.IP 
Perform the action only if the message has not been delivered.
If the action succeeded, then the message is considered delivered.
.\"
.\"
.PP
The file is always read completely,
so that several matches can be made and several actions can be taken.
The 
.PN \&.maildelivery
file must be owned either by the user or by root,
and must be writable only by the owner.
If the 
.PN \&.maildelivery
file cannot be found, or does not perform an action 
which delivers the message, then the file 
.PN /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 perform an action 
which delivers the message,
then standard delivery to the user's maildrop, 
.PN /usr/spool/mail/$USER , 
is performed.
.PP
Arguments in the 
.PN \&.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.
.\"
.\"
.PP
Four programs are currently available:
.PN rcvdist
redistributes incoming messages to additional recipients;
.PN rcvpack 
saves incoming messages in a 
.MS packf 1mh
file; and
.PN rcvtty
notifies the user of incoming messages.
The fourth program,
.PN rcvstore ,
is described in the
.MS rcvstore 1mh
reference page.
They all reside in the 
.PN /usr/lib/mh
directory.
.PP
The 
.PN 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 
.MS mh-format 5mh .
.PP
The 
.PN rcvpack
program appends a copy of the message to the file listed
on its command line.
It is made obsolete by
.PN \&.maildelivery .
.PP
The 
.PN 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 
.PN rcvtty
writes the output to your terminal,
only if your terminal has world-writable permission.
If no valid file is specified, then
.PN rcvtty 
gives a one-line scan listing
to the terminal access daemon.
.\"
.\"
.\"
.\"
.SH Restrictions
For compatibility with older versions of MH, if 
.PN slocal 
cannot find the user's 
.PN \&.maildelivery
file,
it attempts to execute an old-style 
.PN rcvmail 
hook in the user's 
.PN $HOME
directory.
Specifically,
it first attempts to execute the command:
.EX 
\&.mh_receive file maildrop directory user
.EE
Failing that it attempts to execute:
.EX
$HOME/bin/rcvmail user file sender
.EE
If both of these fail, it gives up
and write to the user's maildrop.
.PP
In addition,
whenever a hook or process is invoked,
file-descriptor three (3) is set to the message 
in addition to the standard input.
.PP
Only two return codes are meaningful, others should be.
.\"
.\"
.\"
.\"
.SH Examples
This section shows how
.PN slocal 
could be used.
.PP
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
explanation:
.PP
.TS
tab(@);
l l l l l l.
@\fIfield@pattern@action@result@string\fR
.sp 6p
(1)@To@mmdf2@file@[e-mail]
(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
.TE
.TP 10
Line 1:
File mail with \f(CWmmdf2\fR in the \f(CWTo:\fR line into file 
.PN mmdf2.log .
.TP 10
Line 2:
Messages from \f(CWmmdf\fR are piped to the program 
.PN err-message-archive .
.TP 10
Line 3: 
Take anything with the address \f(CWuk-mmdf\fR
in the \f(CWSender:\fR field, 
and file it in 
.PN mmdf2.log ,
if it has not already been filed by line 1.
.TP 10
Line 4:
Put messages addressed to \f(CWUnix\fR in the file
.PN unix-news .
.TP 10
Line 5:
If the address is \f(CWjpo=mmdf\fR,
pipe the message into 
.PN mmdf-redist .
.TP 10
Line 6:
If the address is \f(CWjpo=ack\fR,
send an acknowledgement copy back.
.TP 10
Line 7:
Destroy anything from \f(CWsteve\fR.
.TP 10
Line 8:
Take anything that is not matched yet
and put it into mailbox.
.TP 10
Line 9:
Always run 
.PN rcvalert .
.\"
.\"
.\"
.\"
.SH Files
.TP 10
.PN /usr/lib/mh/mtstailor
The system customization file.
.TP 10
.PN /usr/lib/mh/maildelivery
The system default file controlling local delivery.
.TP 10
.PN $HOME/.maildelivery
The user-supplied alternative to the system default file
controlling local delivery.
.\"
.\"
.\"
.\"
.SH See Also
rcvstore(1mh)