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

3 files changed, 381 insertions, 0 deletions

diff --git a/sbin/ldattach/Makefile b/sbin/ldattach/Makefile
new file mode 100644
index 00000000000..fd297d48bf6
--- /dev/null
+++ b/sbin/ldattach/Makefile
@@ -0,0 +1,10 @@
+#	$OpenBSD: Makefile,v 1.1 2007/11/03 15:22:54 mbalmer Exp $
+
+PROG=		ldattach
+MAN=		ldattach.8
+
+CFLAGS+=	-Wall -Werror
+
+BINDIR=		/sbin
+
+.include <bsd.prog.mk>
diff --git a/sbin/ldattach/ldattach.8 b/sbin/ldattach/ldattach.8
new file mode 100644
index 00000000000..bc56d232198
--- /dev/null
+++ b/sbin/ldattach/ldattach.8
@@ -0,0 +1,152 @@
+.\"	$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 .
diff --git a/sbin/ldattach/ldattach.c b/sbin/ldattach/ldattach.c
new file mode 100644
index 00000000000..e7fb3238f3b
--- /dev/null
+++ b/sbin/ldattach/ldattach.c
@@ -0,0 +1,219 @@
+/*	$OpenBSD: ldattach.c,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.
+ */
+
+/*
+ * A replacement for slattach(8) and nmeaattach(8) that can be used from
+ * the commandline or from init(8) (using entries in /etc/ttys).
+ */
+
+#include <sys/ioctl.h>
+#include <sys/ttycom.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <termios.h>
+#include <unistd.h>
+
+__dead void	usage(void);
+void 		coroner(int);
+
+volatile sig_atomic_t dying = 0;
+
+__dead void
+usage(void)
+{
+	extern char *__progname;
+
+	fprintf(stderr, "usage: %s [-7dehmo] [-s baudrate] "
+	    "[-t cond] discipline device\n", __progname);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct termios tty;
+	struct tstamps tstamps;
+	const char *errstr;
+	tcflag_t cflag = HUPCL | CS8;
+	sigset_t sigset;
+	pid_t ppid;
+	int ch, fd, ldisc, nodaemon = 0, speed = B4800, parity = 0;
+	char devname[32], *dev, *disc;
+
+	tstamps.ts_set = tstamps.ts_clr = 0;
+
+	if ((ppid = getppid()) == 1)
+		nodaemon = 1;
+
+	while ((ch = getopt(argc, argv, "7dehmos:t:")) != -1) {
+		switch (ch) {
+		case '7':
+			cflag &= ~CS8;
+			cflag |= CS7;
+			break;
+		case 'd':
+			nodaemon = 1;
+			break;
+		case 'e':
+			if (parity != 0)
+				parity = 0;	/* -o -e */
+			else
+				parity = -1;	/* even */
+			break;
+		case 'h':
+			cflag |= CRTSCTS;
+			break;
+		case 'm':
+			cflag &= ~HUPCL;
+			break;
+		case 'o':
+			if (parity != 0)
+				parity = 0;	/* -e -o */
+			else
+				parity = 1;	/* odd */
+			break;
+		case 's':
+			speed = (int)strtonum(optarg, 50, 230400, &errstr);
+			if (errstr) {
+				if (ppid != 1)
+					errx(1,  "speed is %s: %s", errstr,
+					    optarg);
+				else
+					goto bail_out;
+			}
+			break;
+		case 't':
+			if (!strcasecmp(optarg, "dcd"))
+				tstamps.ts_set |= TIOCM_CAR;
+			else if (!strcasecmp(optarg, "!dcd"))
+				tstamps.ts_clr |= TIOCM_CAR;
+			else if (!strcasecmp(optarg, "cts"))
+				tstamps.ts_set |= TIOCM_CTS;
+			else if (!strcasecmp(optarg, "!cts"))
+				tstamps.ts_clr |= TIOCM_CTS;
+			else {
+				if (ppid != 1)
+					errx(1, "'%s' not supported for "
+					    "timestamping", optarg);
+				else
+					goto bail_out;
+			}
+			break;
+		default:
+			if (ppid != -1)
+				usage();
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if (ppid != 1 && argc != 2)
+		usage();
+
+	disc = *argv++;
+	dev = *argv;
+	if (strncmp(_PATH_DEV, dev, sizeof(_PATH_DEV) - 1)) {
+		(void)snprintf(devname, sizeof(devname),
+		    "%s%s", _PATH_DEV, dev);
+		dev = devname;
+	}
+	syslog(LOG_INFO, "attach %s on %s", disc, dev);
+	if ((fd = open(dev, O_RDWR)) < 0)
+		goto bail_out;
+
+	if (!strcmp(disc, "slip"))
+		ldisc = SLIPDISC;
+	else if (!strcmp(disc, "nmea"))
+		ldisc = NMEADISC;
+	else {
+		syslog(LOG_ERR, "unknown line discipline %s", disc);
+		goto bail_out;
+	}
+
+	switch (parity) {
+	case -1:	/* even parity */
+		cflag |= PARENB;
+		break;
+	case 1:		/* odd parity */
+		cflag |= PARENB | PARODD;
+		break;
+	}
+	
+	tty.c_cflag = CREAD | cflag;
+	tty.c_iflag = 0;
+	tty.c_lflag = 0;
+	tty.c_oflag = 0;
+	tty.c_cc[VMIN] = 1;
+	tty.c_cc[VTIME] = 0;
+	cfsetspeed(&tty, speed);
+	if (tcsetattr(fd, TCSADRAIN, &tty) < 0) {
+		if (ppid != 1)
+			warnx("tcsetattr");
+		goto bail_out;
+	}
+
+	/* setup common to all line disciplines */
+	if (ioctl(fd, TIOCSDTR, 0) < 0)
+		warn("TIOCSDTR");
+	if (ioctl(fd, TIOCSETD, &ldisc) < 0) {
+		syslog(LOG_ERR, "can't set the %s line discipline on %s", disc,
+		    dev);
+		goto bail_out;
+	}
+
+	/* line discpline specific setup */
+	switch (ldisc) {
+	case NMEADISC:
+		if (ioctl(fd, TIOCSTSTAMP, &tstamps) < 0) {
+			warnx("TIOCSTSTAMP");
+			goto bail_out;
+		}
+		break;
+	}
+
+	if (!nodaemon && daemon(0, 0))
+		errx(1, "can't daemonize");
+
+	signal(SIGHUP, coroner);
+	signal(SIGTERM, coroner);
+
+	sigemptyset(&sigset);
+	while (!dying)
+		sigsuspend(&sigset);
+
+bail_out:
+	if (ppid == 1)
+		sleep(30);	/* delay restart when called from init */
+
+	return 0;
+}
+
+/* ARGSUSED */
+void
+coroner(int useless)
+{
+	dying = 1;
+}