Make uucp-locking optional: -L option

2 files changed, 105 insertions, 53 deletions

diff --git a/sbin/slattach/slattach.8 b/sbin/slattach/slattach.8
index 57ec88b..3b304c7 100644
--- a/sbin/slattach/slattach.8
+++ b/sbin/slattach/slattach.8
@@ -31,7 +31,7 @@
 .\"
 .\"     @(#)slattach.8	6.4 (Berkeley) 3/16/91
 .\"
-.\"	$Header: /home/ncvs/src/sbin/slattach/slattach.8,v 1.5 1995/09/18 13:33:28 ache Exp $
+.\"	$Header: /home/ncvs/src/sbin/slattach/slattach.8,v 1.6 1995/09/18 14:06:36 ache Exp $
 .\"
 .Dd April 4, 1993
 .Dt SLATTACH 8
@@ -40,7 +40,7 @@
 .Nm slattach
 .Nd attach serial lines as network interfaces
 .Sh SYNOPSIS
-.Nm Slattach
+.Nm slattach
 .Op Fl a
 .Op Fl c
 .Op Fl e Ar exit-command
@@ -48,10 +48,11 @@
 .Op Fl h
 .Op Fl l
 .Op Fl n
+.Op Fl z
+.Op Fl L
 .Op Fl r Ar redial-command
 .Op Fl s Ar baudrate
 .Op Fl u Ar unit-command
-.Op Fl z
 .Op Fl K Ar keepalive
 .Op Fl O Ar outfill
 .Op Fl S Ar unit
@@ -71,39 +72,62 @@ headers will be used.
 Enables the VJ header compression option.  Note that both ends of the link
 must be able to use VJ header compression for this to work.
 .It Fl e Ar exit-command
-Specifies a command to be invoked within a shell (sh -c exit-command)
-before slattach exits.
+Specifies a command to be invoked within a shell
+.Ql sh \-c Ar exit-command
+before
+.Nm slattach
+exits.
 .It Fl f
-Disables the invocation of daemon() to run slattach in the background.
+Disables the invocation of daemon() to run
+.Nm slattach
+in the background.
 .It Fl h
 Turn on cts/rts style flow control on the slip port, by default no flow
 control is done.
 .It Fl l
 disable modem control (CLOCAL) and ignore carrier detect on the slip
-port.  By default the redial-command is invoked upon carrier drop and
-slattach aborts if no redial-command is specified.
+port.  By default the
+.Ar redial-commmand
+is invoked upon carrier drop and
+.Nm slattach
+aborts if no
+.Ar redial-commmand
+is specified.
 .It Fl n
 Throw away ICMP packets.  The slip interface will ignore ICMP packets
 to prevent slow lines being saturated by ICMP responses.
-.It Fl r Ar redial-command
-Specifies a command to be invoked within a shell (sh -c
-redial-command) whenever carrier is lost on the line.
+.It Fl r Ar redial-commmand
+Specifies a command to be invoked within a shell
+.Ql sh \-c Ar redial-command
+whenever carrier is lost on the line.
 .It Fl s Ar baudrate
 Specifies the speed of the connection. If not specified, the
 default of 9600 is used.
 .It Fl u Ar unit-command
 When the line is switched to slip discipline, run
-.Ql sh \-c unit-command <last> <current> 
-where <last> and <current> are the slip unit numbers when the line was
+.Ql sh \-c Ar unit-command <last> <current>
+where
+.Ar <last>
+and
+.Ar <current>
+are the slip unit numbers when the line was
 last opened and the unit number of the current slip connection
 respecitvely.  The unit number can change after redialing if you are
-using more than one slip line.  Slattach will abort if the unit number
+using more than one slip line.
+.Nm Slattach
+will abort if the unit number
 changes and
-.Ql \-u unit-command
+.Fl u Ar unit-command
 was not specified.
 .It Fl z
 forces redial
-redial-cmd upon startup irrespective of carrier.
+.Ar redial-command
+upon startup irrespective of carrier.
+.It Fl L
+Use uucp-style device locking. You need it unless you start
+.Nm slattach
+from external program which already does uucp locking.
+Default case is no uucp locking to satisfy such programs.
 .It Fl K Ar keepalive
 Set SLIP "keep alive" timeout in seconds. If FRAME_END not received in this
 timeout, reconnect occurse. Active "out fill" timeout expected from other
@@ -122,8 +146,9 @@ Default is dynamic assignment.
 Specifies the name of the tty device.
 .Ar Ttyname
 should be a string of the form 
-.Ql ttyXX or
-.Ql /dev/ttyXX.
+.Ql ttyXX
+or
+.Ql /dev/ttyXX .
 .El
 .Pp
 Only the super-user may attach a network interface.
@@ -138,49 +163,63 @@ process using
 is the name that is shown by
 .Xr netstat 1
 .Pp
-To setup slattach to redial the phone when carrier is lost, use the
-.Ql \-r redial-cmd
+To setup
+.Nm slattach
+to redial the phone when carrier is lost, use the
+.Fl r Ar redial-command
 option to specify a script or executable that will reconnect the
 serial line to the slip server.  For example, the script could redial
 the server and log in, etc.
 .Pp
 To reconfigure the network interface in case the slip unit number
 changes, use the
-.Ql \-u unit-cmd
+.Fl u Ar unit-command
 option to specify a script or executable that will be invoked as 
-.Ql sh \-c unit-cmd old new,
-where old and new are the slip unit numbers before and after
+.Ql sh \-c Ar unit-command old new
+where
+.Ar old
+and
+.Ar new
+are the slip unit numbers before and after
 reconnecting the line.  The unit number can change if you have more
 than one line disconnect at the same time.  The first to succeed in
 reconnecting will get the lowest unit number.
 .Pp
-To kill slattach use
+To kill
+.Nm slattach
+use
 .Ql kill -INT
 (SIGINT) which causes it to close the tty and exit.
 .Pp
 To force a redial, use
 .Ql kill -HUP
-(SIGHUP) which causes slattach to think carrier was lost and thus invoke 
-.Ql sh -c redial-command
+(SIGHUP) which causes
+.Nm slattach
+to think carrier was lost and thus invoke
+.Ql sh \-c Ar redial-command
 to reconnect to the server.
 .Pp
 If you use a hard-wired connection rather than a modem, invoke
-slattach with the
-.Ql \-l
+.Nm slattach
+with the
+.Fl l
 option in order to ignore carrier on the slip line.
 .Sh EXAMPLES
 .Bd -literal -offset indent -compact
-slattach ttyh8
-slattach \-s 4800 /dev/tty01
-slattach \-c \-s 38400 /dev/sio01
+slattach ttyd8
+slattach \-s 4800 /dev/ttyd1
+slattach \-c \-s 38400 /dev/cuaa1
 slattach \-r 'kermit -y dial.script >kermit.log 2>&1'
 .Ed
 .Sh DIAGNOSTICS
-Look for error messages in /var/log/messages (slattach is a daemon).
+Look for error messages in /var/log/messages (
+.Nm slattach
+is a daemon).
 Messages indicating the specified interface does not exit, the
 requested address is unknown, the user is not privileged and tried to
-alter an interface's configuration are logged there.  Slattach also
-logs failure to set the controlling terminal or failure to install
+alter an interface's configuration are logged there.
+.Nm Slattach
+also logs failure to set the controlling terminal or failure to install
 signal handlers.  Upon connection and redial the ttyname and baud rate
 are logged and on shutdown the ttyname is logged.
 .Pp
@@ -188,20 +227,21 @@ are logged and on shutdown the ttyname is logged.
 .Pa /var/run/slattach.<tty>.pid ,
 .Pp
 with
-.Aq tty
+.Ar tty
 replaced by the terminal path name component of
 .Ar ttyname .
 This file contains the numerical process ID of the
 .Nm slattach
 process and can be examined by scripts in oder to send a signal to
-.Nm slattch .
+.Nm slattach .
 .Sh SEE ALSO
 .Xr startslip 1 ,
 .Xr sliplogin 8 ,
 .Xr netstat 1 ,
 .Xr netintro 4 ,
 .Xr ifconfig 8 ,
-.Xr rc 8
+.Xr rc 8 ,
+.Xr uustat 1
 .Sh HISTORY
 The
 .Nm
diff --git a/sbin/slattach/slattach.c b/sbin/slattach/slattach.c
index 4a01e5a..cfd8275 100644
--- a/sbin/slattach/slattach.c
+++ b/sbin/slattach/slattach.c
@@ -78,7 +78,7 @@ void	acquire_line();		/* get tty device as controling terminal */
 int	fd = -1;
 char	*dev = (char *)0;	/* path name of the tty (e.g. /dev/tty01) */
 char    *dvname;                /* basename of dev */
-int     locked = 0;             /* uucp lock */
+int     locked = 0;             /* uucp lock active */
 int	flow_control = 0;	/* non-zero to enable hardware flow control. */
 int	modem_control =	HUPCL;	/* !CLOCAL+HUPCL iff we	watch carrier. */
 int	comstate;		/* TIOCMGET current state of serial driver */
@@ -90,6 +90,7 @@ int	foreground = 0;		/* act as demon if zero, else don't fork. */
 int     keepal = 0;             /* keepalive timeout */
 int     outfill = 0;            /* outfill timeout */
 int     sl_unit = -1;           /* unit number */
+int     uucp_lock = 0;          /* do uucp locking */
 int	exiting = 0;		/* allready running exit_handler */
 
 struct	termios tty;		/* tty configuration/state */
@@ -102,7 +103,7 @@ char	*exit_cmd = 0;		/* command to exec before exiting. */
 
 static char usage_str[] = "\
 usage: %s [-acfhlnz] [-e command] [-r command] [-s speed] [-u command] \\\n\
-	  [-K timeout] [-O timeout] [-S unit] device\n\
+	  [-L] [-K timeout] [-O timeout] [-S unit] device\n\
   -a      -- autoenable VJ compression\n\
   -c      -- enable VJ compression\n\
   -e ECMD -- run ECMD before exiting\n\
@@ -114,6 +115,7 @@ usage: %s [-acfhlnz] [-e command] [-r command] [-s speed] [-u command] \\\n\
   -s #    -- set baud rate (default 9600)\n\
   -u UCMD -- run 'UCMD <old sl#> <new sl#>' before switch to slip discipline\n\
   -z      -- run RCMD upon startup irrespective of carrier\n\
+  -L      -- do uucp-style device locking\n\
   -K #    -- set SLIP \"keep alive\" timeout (default 0)\n\
   -O #    -- set SLIP \"out fill\" timeout (default 0)\n\
   -S #    -- set SLIP unit number (default is dynamic)\n\
@@ -125,7 +127,7 @@ int main(int argc, char **argv)
 	extern char *optarg;
 	extern int optind;
 
-	while ((option = getopt(argc, argv, "ace:fhlnr:s:u:zK:O:S:")) != EOF) {
+	while ((option = getopt(argc, argv, "ace:fhlnr:s:u:zLK:O:S:")) != EOF) {
 		switch (option) {
 		case 'a':
 			slflags |= IFF_LINK2;
@@ -162,6 +164,9 @@ int main(int argc, char **argv)
 		case 'z':
 			redial_on_startup = 1;
 			break;
+		case 'L':
+			uucp_lock = 1;
+			break;
 		case 'K':
 			keepal = atoi(optarg);
 			break;
@@ -281,12 +286,14 @@ void acquire_line()
 	if ((int)signal(SIGHUP,sighup_handler) < 0) /* Re-enable HUP signal */
 		syslog(LOG_NOTICE,"cannot install SIGHUP handler: %m");
 
-	/* unlock not needed here, always re-lock with new pid */
-	if (uu_lock(dvname)) {
-		syslog(LOG_ERR, "can't lock %s", dev);
-		exit_handler(1);
+	if (uucp_lock) {
+		/* unlock not needed here, always re-lock with new pid */
+		if (uu_lock(dvname)) {
+			syslog(LOG_ERR, "can't lock %s", dev);
+			exit_handler(1);
+		}
+		locked = 1;
 	}
-	locked = 1;
 
 	if ((fd = open(dev, O_RDWR | O_NONBLOCK, 0)) < 0) {
 		syslog(LOG_ERR, "open(%s) %m", dev);
@@ -440,16 +447,21 @@ again:
 		setup_line(CLOCAL);
 		syslog(LOG_NOTICE,"SIGHUP on %s (sl%d); running %s",
 		       dev,unit,redial_cmd);
-		uu_unlock(dvname);      /* for redial */
-		locked = 0;
+		if (locked) {
+			if (uucp_lock)
+				uu_unlock(dvname);      /* for redial */
+			locked = 0;
+		}
 		if (system(redial_cmd))
 			goto again;
-		if (uu_lock(dvname)) {
-			syslog(LOG_ERR, "can't relock %s after %s, aborting",
-				dev, redial_cmd);
-			exit_handler(1);
+		if (uucp_lock) {
+			if (uu_lock(dvname)) {
+				syslog(LOG_ERR, "can't relock %s after %s, aborting",
+					dev, redial_cmd);
+				exit_handler(1);
+			}
+			locked = 1;
 		}
-		locked = 1;
 		/* Now check again for carrier (dial command is done): */
 		if (!(modem_control & CLOCAL)) {
 			tty.c_cflag &= ~CLOCAL;
@@ -538,7 +550,7 @@ void exit_handler(int ret)
 	 */
 	if (fd != -1)
 		close(fd);
-	if (locked)
+	if (uucp_lock && locked)
 		uu_unlock(dvname);
 
 	/* Remove the PID file */