svn commit: r294735 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Mon Jan 25 16:47:20 2016
New Revision: 294735
URL: https://svnweb.freebsd.org/changeset/base/294735

Log:
  Don't allow opening the callout device when the callin device is already
  open (in disguise as the console device).  The only allowed combination
  was supposed to be the callin device with the console.
  
  Fix the assertion in ttydev_close() that was meant to detect this (it
  only detected all 3 devices being open).  Assert this in ttydev_open()
  too.
  
  Submitted by:	bde
  MFC after:	2 weeks

Modified:
  head/sys/kern/tty.c

Modified: head/sys/kern/tty.c
==============================================================================
--- head/sys/kern/tty.c	Mon Jan 25 16:18:53 2016	(r294734)
+++ head/sys/kern/tty.c	Mon Jan 25 16:47:20 2016	(r294735)
@@ -263,10 +263,10 @@ ttydev_open(struct cdev *dev, int oflags
 
 	/*
 	 * Make sure the "tty" and "cua" device cannot be opened at the
-	 * same time.
+	 * same time.  The console is a "tty" device.
 	 */
 	if (TTY_CALLOUT(tp, dev)) {
-		if (tp->t_flags & TF_OPENED_IN) {
+		if (tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) {
 			error = EBUSY;
 			goto done;
 		}
@@ -319,6 +319,8 @@ ttydev_open(struct cdev *dev, int oflags
 		tp->t_flags |= TF_OPENED_OUT;
 	else
 		tp->t_flags |= TF_OPENED_IN;
+	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
+	    (tp->t_flags & TF_OPENED_OUT) == 0);
 
 done:	tp->t_flags &= ~TF_OPENCLOSE;
 	cv_broadcast(&tp->t_dcdwait);
@@ -338,7 +340,8 @@ ttydev_close(struct cdev *dev, int fflag
 	 * Don't actually close the device if it is being used as the
 	 * console.
 	 */
-	MPASS((tp->t_flags & TF_OPENED) != TF_OPENED);
+	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
+	    (tp->t_flags & TF_OPENED_OUT) == 0);
 	if (dev == dev_console)
 		tp->t_flags &= ~TF_OPENED_CONS;
 	else