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.\" $OpenBSD: ldattach.8,v 1.5 2007/11/03 16:59:34 deraadt Exp $
.\"
.\" Copyright (c) 2007 Marc Balmer <mbalmer@openbsd.org>
.\"
.\" 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.
.\"
.\" 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
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: November 3 2007 $
.Dt LDATTACH 8
.Os
.Sh NAME
.Nm ldattach
.Nd attach a line discipline to a serial line
.Sh SYNOPSIS
.Nm ldattach
.Op Fl 7dehmo
.Op Fl s Ar baudrate
.Op Fl t Ar cond
.Ar discipline
.Ar device
.Sh DESCRIPTION
.Nm
is used to attach a line discipline to a serial line to allow for in-kernel
processing of the received and/or sent data.
Depending on the line discipline being attached, one or more options may be
applied.
.Pp
.Nm
can be used from the command line or in
.Xr ttys 5
entries to attach line disciplines at system startup time by having
.Xr init 8
start
.Nm
on the designated interface.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl 7
Use 7 databits instead of 8.
.It Fl d
Do not daemonize.
.It Fl e
Use even parity.
If both
.Fl e
and
.Fl o
are given, then no parity is used (the default).
.It Fl h
Turn on RTS/CTS flow control.
By default, no flow control is done.
.It Fl m
Maintain modem control signals after closing the line.
Specifically, this disables HUPCL.
.It Fl o
Use odd parity.
If both
.Fl e
and
.Fl o
are given, then no parity is used (the default).
.It Fl s Ar baudrate
Specifies the speed of the connection.
If not specified, the default of 4800 baud is used.
.It Fl t Ar cond
.Xr nmea 4
line discipline only.
Chooses the condition which will cause the current system time to be
immediately copied to the terminal timestamp storage for subsequent use by
.Xr nmea 4 .
Only one can be used.
.Pp
.Bl -tag -width DCDXX -offset indent -compact
.It dcd
Copy the timestamp when DCD is asserted.
.It !dcd
Copy the timestamp when DCD is deasserted.
.It cts
Copy the timestamp when CTS is asserted.
.It !cts
Copy the timestamp when CTS is deasserted.
.El
.Pp
If no condition is specified, the
.Xr nmea 4
line discipline will timestamp on receiving the leading
.Sq $
character of each block of NMEA sentences.
.It Ar discipline
Specifies the name of the line discipline to be attached.
.Pp
.Bl -tag -width nmeaXX -offset -indet -compact
.It nmea
Attach the
.Xr nmea 4
line discipline.
.It slip
Attach the
.Xr sl 4
line discipline.
.El
.It Ar device
Specifies the name of the serial line.
.Ar device
should be a string of the form
.Dq cuaXX
or
.Dq /dev/cuaXX .
.El
.Pp
If
.Nm
was not started by
.Xr init 8 ,
the line discipline can be detached by
killing off the
.Nm
process.
.Sh EXAMPLES
To start
.Nm
using
.Xr init 8
to attach the
.Xr nmea 4
line discipline to
.Pa /dev/tty01
at 4800 baud,
add a line of the following form to
.Pa /etc/ttys :
.Bd -literal -offset indent
tty01 "/sbin/ldattach nmea" unknown on
.Ed
.Sh SEE ALSO
.Xr nmea 4 ,
.Xr sl 4 ,
.Xr tty 4 ,
.Xr ttys 5
.Sh HISTORY
The
.Nm
command first appeared in
.Ox 4.3 .
|
