I finally had enough of tip not recognizing carrier loss. now it does.

usr.bin/tip/tip.c

@@ -62,6 +62,7 @@ int	disc = OTTYDISC;		/* tip normally runs this way */
 void	intprompt();
 void	timeout();
 void	cleanup();
+void	tipdone();
 char	*sname();
 char	PNbuf[256];			/* This limits the size of a number */
 
@@ -138,6 +139,7 @@ main(argc, argv)
 	(void)signal(SIGQUIT, cleanup);
 	(void)signal(SIGHUP, cleanup);
 	(void)signal(SIGTERM, cleanup);
+	(void)signal(SIGUSR1, tipdone);
 
 	if ((i = hunt(system)) == 0) {
 		printf("all ports busy\n");
@@ -237,6 +239,11 @@ cleanup()
 	exit(0);
 }
 
+void
+tipdone()
+{
+	tipabort("Hangup.");
+}
 /*
  * Muck with user ID's.  We are setuid to the owner of the lock
  * directory when we start.  user_uid() reverses real and effective

usr.bin/tip/tip.h

@@ -276,3 +276,5 @@ extern	int disc;			/* current tty discpline */
 extern	char *ctrl();
 extern	char *vinterp();
 extern	char *connect();
+
+int	tipabort	__P((char *));

usr.bin/tip/tipout.c

@@ -136,6 +136,14 @@ tipout()
 				sigblock(sigmask(SIGTERM));
 				intTERM();
 				/*NOTREACHED*/
+			} else if (cnt == 0 && errno == ENOENT) {
+				kill(getppid(),SIGUSR1);
+				sigblock(sigmask(SIGTERM));
+				intTERM();
+				/*NOTREACHED*/
+			} else {
+				printf("%d %d\r",cnt,errno);
+				fflush(stdout);
 			}
 			continue;
 		}