OpenBSD-4.6/libexec/lockspool/lockspool.1

.\"	$OpenBSD: lockspool.1,v 1.10 2008/10/01 20:33:07 millert Exp $
.\"
.\" Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: October 1 2008 $
.Dt LOCKSPOOL 1
.Os
.Sh NAME
.Nm lockspool
.Nd lock user's system mailbox
.Sh SYNOPSIS
.Nm lockspool
.Op Ar username
.Sh DESCRIPTION
.Nm
is useful for a client mail program to attain proper locking.
.Nm
obtains a
.Pa username.lock
for the calling user and retains it until stdin is closed or a signal like
.Dv SIGINT ,
.Dv SIGTERM ,
or
.Dv SIGHUP
is received.
Additionally, the superuser may specify the name of a user in order
to lock a different mailbox.
.Pp
If
.Nm
is able to create the lock file,
.Dq 1
is written to stdout, otherwise
.Dq 0
is written and an error message is written to stderr.
.Nm
will try up to 10 times to get the lock (sleeping
for a short period in between tries).
.Pp
Typical usage is for a user mail agent (such as
.Xr mail 1 )
to open a pipe to
.Nm
when it needs to lock the user's mail spool.
Closing the pipe will cause
.Nm
to release the lock.
.Pp
The
.Nm
utility exits 0 on success, and 1 if an error occurs.
.Sh FILES
.Bl -tag -width /var/mail/username.lock -compact
.It Pa /var/mail/username.lock
user's mail lock file
.El
.Sh SEE ALSO
.Xr mail 1 ,
.Xr mail.local 8 ,
.Xr sendmail 8
.Sh HISTORY
The
.Nm
program appeared in
.Ox 2.4 .