ldattach(8) is a command to attach line discipline to a tty line. It can

be used from the command line or from init(8) by adding an entry to the
/etc/ttys file.  ldattach(8) can be extended to support new line disciplines.

feedback many, ok deraadt, mikeb

1 files changed, 152 insertions, 0 deletions

diff --git a/sbin/ldattach/ldattach.8 b/sbin/ldattach/ldattach.8
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+.\"	$OpenBSD: ldattach.8,v 1.1 2007/11/03 15:22:54 mbalmer 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
+by using
+.Xr init 8
+to attach the
+.Xr nmea 4
+line discipline to
+.Pa /dev/cua00 ,
+add a line of the following form to
+.Pa /etc/ttys :
+.Bd -literal -offset indent
+cua00	"/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 .