Fix line discipline switching issues: If opening a new ldisc fails,

we have to revert to TTYDISC which we know will successfully open
rather than try the previous ldisc which might also fail to open.

Do not let ldisc implementations muck about with ->t_line, and remove
code which checks for reopens, it should never happen.

Move ldisc->l_hotchar to tty->t_hotchar and have ldisc implementation
initialize it in their open routines.  Reset to zero when we enter
TTYDISC.  ("no" should really be -1 since zero could be a valid
hotchar for certain old european mainframe protocols.)

1 files changed, 2 insertions, 10 deletions

diff --git a/sys/net/ppp_tty.c b/sys/net/ppp_tty.c
index 0270acbb95bf..05ffb169ab6d 100644
--- a/sys/net/ppp_tty.c
+++ b/sys/net/ppp_tty.c
@@ -148,8 +148,7 @@ void		pppasyncdetach(void);
 
 static struct linesw pppdisc = {
 	pppopen,	pppclose,	pppread,	pppwrite,
-	ppptioctl,	pppinput,	pppstart,	ttymodem,
-	PPP_FLAG
+	ppptioctl,	pppinput,	pppstart,	ttymodem
 };
 
 void
@@ -185,13 +184,7 @@ pppopen(dev, tp)
 
     s = spltty();
 
-    if (tp->t_line == PPPDISC) {
-	sc = (struct ppp_softc *) tp->t_sc;
-	if (sc != NULL && sc->sc_devp == (void *) tp) {
-	    splx(s);
-	    return (0);
-	}
-    }
+    tp->t_hotchar = PPP_FLAG;
 
     if ((sc = pppalloc(td->td_proc->p_pid)) == NULL) {
 	splx(s);
@@ -254,7 +247,6 @@ pppclose(tp, flag)
     ttyflush(tp, FREAD | FWRITE);
     clist_free_cblocks(&tp->t_canq);
     clist_free_cblocks(&tp->t_outq);
-    tp->t_line = 0;
     sc = (struct ppp_softc *) tp->t_sc;
     if (sc != NULL) {
 	tp->t_sc = NULL;