src/libexec/mail.local/mail.local.8

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.\" $OpenBSD: mail.local.8,v 1.33 2022/03/31 17:27:19 naddy Exp $
.\" Copyright (c) 1990 The Regents of the University of California.
.\" All rights reserved.
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.\" modification, are permitted provided that the following conditions
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.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
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.\" may be used to endorse or promote products derived from this software
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" from: @(#)mail.local.8 6.8 (Berkeley) 4/27/91
.\"
.Dd $Mdocdate: March 31 2022 $
.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 effort has been made to ensure that
.Nm
acts as securely as possible.
It will only deliver to a mail spool directory that is not world-writable.
The default mode of
.Pa /var/mail
on
.Ox
is 755, which prevents non-root processes from creating mail spool files.
The MTA is expected to either create the mail spool file itself, or call
.Nm
as root.
.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.
.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 EXIT STATUS
.Ex -std mail.local
.Sh SEE ALSO
.Xr biff 1 ,
.Xr mail 1 ,
.Xr flock 2 ,
.Xr getservbyname 3 ,
.Xr comsat 8 ,
.Xr smtpd 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
Using quotas in
.Pa /var/mail
can be problematic if using
.Xr sendmail 8
as an MTA,
since it asks
.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.
This problem does not exist for
.Xr smtpd 8
users.
.Pp
If you are running
.Xr sendmail 8
and have 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 ) .