From 605f11c8f23aa432b1ace122c34b3031c0ee1b5e Mon Sep 17 00:00:00 2001
From: David Greenman <dg@FreeBSD.org>
Date: Thu, 18 Aug 1994 03:53:38 +0000
Subject: [PATCH] Moved over my fix for vnode lossage when multiple TIOCSCTTY
 ioctls are done. This patch was extended to also include a suggested change
 by Kirk McKusick which allows the control tty to be reasigned to a different
 tty without losing a vnode.

---
 sys/kern/vfs_vnops.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 2b6429912f27..7229c33c4871 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_vnops.c	8.2 (Berkeley) 1/21/94
- * $Id$
+ * $Id: vfs_vnops.c,v 1.3 1994/08/02 07:43:33 davidg Exp $
  */
 
 #include <sys/param.h>
@@ -398,6 +398,15 @@ vn_ioctl(fp, com, data, p)
 	case VBLK:
 		error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p);
 		if (error == 0 && com == TIOCSCTTY) {
+
+			/* Do nothing if reassigning same control tty */
+			if (p->p_session->s_ttyvp == vp)
+				return (0);
+
+			/* Get rid of reference to old control tty */
+			if (p->p_session->s_ttyvp)
+				vrele(p->p_session->s_ttyvp);
+
 			p->p_session->s_ttyvp = vp;
 			VREF(vp);
 		}