Readd rev. 1.145 because of vfs bugs and races near revoke(). Until they

are fixed we can't free any slaves. Add a workaround to not to leak ptys
by number.

1 files changed, 14 insertions, 4 deletions

diff --git a/sys/kern/tty_pty.c b/sys/kern/tty_pty.c
index 4afb803..2f1b2eb 100644
--- a/sys/kern/tty_pty.c
+++ b/sys/kern/tty_pty.c
@@ -184,7 +184,11 @@ static void
 pty_maybe_destroy_slave(struct ptsc *pt)
 {
 
-	if (pt->pt_devc_open == 0 && pt->pt_devs_open == 0)
+	/*
+	 * vfs bugs and complications near revoke() make
+	 * it currently impossible to destroy struct cdev
+	 */
+	if (0 && pt->pt_devc_open == 0 && pt->pt_devs_open == 0)
 		pty_destroy_slave(pt);
 }
 
@@ -328,12 +332,18 @@ ptcopen(struct cdev *dev, int flag, int devtype, struct thread *td)
 		pt->pt_tty = ttyalloc();
 		pt->pt_tty->t_sc = pt;
 		dev->si_tty = pt->pt_tty;
-		pty_create_slave(td->td_ucred, pt, minor(dev));
 	}
 	tp = dev->si_tty;
 
-	if (tp->t_oproc)
-		return (EIO);
+	if (tp->t_oproc) {
+		/*
+		 * Only return if we have a non empty
+		 * state to avoid leakage. Workaround for
+		 * vfs bugs and complications near revoke().
+		 */
+		if (tp->t_state != 0x0 || tp->t_refcnt > 1)
+			return (EIO);
+	}
 	tp->t_timeout = -1;
 	tp->t_oproc = ptsstart;
 	tp->t_stop = ptsstop;