OpenBSD-4.6/libexec/mail.local/mail.local.8

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.\"	$OpenBSD: mail.local.8,v 1.28 2009/01/19 09:46:59 sobrado Exp $
.\" Copyright (c) 1990 The Regents of the University of California.
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.\"	from: @(#)mail.local.8	6.8 (Berkeley) 4/27/91
.\"
.Dd $Mdocdate: January 19 2009 $
.Dt MAIL.LOCAL 8
.Os
.Sh NAME
.Nm mail.local
.Nd store mail in a mailbox
.Sh SYNOPSIS
.Nm mail.local
.Op Fl Ll
.Op Fl f Ar from
.Ar user ...
.Sh DESCRIPTION
.Nm
reads the standard input up to an end-of-file and appends it to each
.Ar user Ns 's
.Pa mail
file.
The
.Ar user
must be a valid user name.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl f Ar from
Specify the sender's name.
.It Fl L
Don't create a
.Pa username.lock
file while locking the spool.
.It Fl l
For compatibility, request that files named
.Pa username.lock
be used for locking.
(This is the default behavior.)
.El
.Pp
Individual mail messages in the mailbox are delimited by an empty
line followed by a line beginning with the string
.Dq "From\&\ " .
A line containing the string
.Dq "From\&\ " ,
the sender's name and a timestamp is prepended to each delivered mail message.
A blank line is appended to each message.
A greater-than character
.Pq Ql >
is prepended to any line in the message which could be mistaken for a
.Dq "From\&\ "
delimiter line.
.Pp
Significant efforts have been made to ensure that
.Nm
acts as securely as possible if the spool directory is mode 1777 or 755.
The default of mode 755 is more secure, but it prevents mail clients from using
.Pa username.lock
style locking.
The use of 1777 is more flexible in an NFS shared-spool environment,
so many sites use it.
However, it does carry some risks, such as attackers filling the spool disk.
Some of these problems may be alleviated
by making the spool a separate filesystem, and placing quotas on it.
The use of any mode other than 1777 and 755 for the spool directory is
recommended against but may work properly.
.Pp
The mailbox is always locked using
.Xr flock 2
while mail is appended.
Unless the
.Fl L
flag is specified, a
.Pa username.lock
file is also used.
.Pp
If the
.Xr biff 1
service is returned by
.Xr getservbyname 3 ,
the biff server is notified of delivered mail.
.Pp
.Ex -std mail.local
.Sh ENVIRONMENT
.Bl -tag -width indent
.It Ev TZ
Used to set the appropriate time zone on the timestamp.
.El
.Sh FILES
.Bl -tag -width /tmp/local.XXXXXXXXXX -compact
.It Pa /tmp/local.XXXXXXXXXX
temporary files
.It Pa /var/mail/user
user's mailbox directory
.El
.Sh SEE ALSO
.Xr biff 1 ,
.Xr mail 1 ,
.Xr flock 2 ,
.Xr getservbyname 3 ,
.Xr comsat 8 ,
.Xr sendmail 8
.Sh HISTORY
A superset of
.Nm
(handling mailbox reading as well as mail delivery) appeared in
.At v7
as the program
.Xr mail 1 .
.Sh BUGS
Since
.Xr sendmail 8
bases its idea of whether a message has been delivered or not
on the return value from
.Nm mail.local ,
using quotas in
.Pa /var/mail
can be problematic.
By default,
.Xr sendmail 8
will ask
.Nm
to deliver a message to multiple recipients if possible.
This causes problems in a quota environment since a message may be
delivered to some users but not others due to disk quotas.
Even though the message was delivered to some of the recipients,
.Nm
will exit with an exit code > 0, causing
.Xr sendmail 8
to attempt redelivery later.
That means that some users will keep getting the same message every time
.Xr sendmail 8
runs its queue.
.Pp
If you are running with disk quotas on
.Pa /var/mail
it is imperative that you unset the
.Dq m
mailer flag for the
.Sq local
mailer.
To do this, locate the line beginning with
.Dq Mlocal
in
.Pa /etc/mail/sendmail.cf
and remove the
.Dq m
from the flags section, denoted by
.Dq F= .
Alternately, you can override the default mailer flags by adding the line:
.Pp
.Dl define(`LOCAL_MAILER_FLAGS', `rn9S')dnl
.Pp
to your
.Dq \.mc
file (this is the source file that is used to generate
.Pa /etc/mail/sendmail.cf ) .