12306 XPG4v2 slave pty behaviour should generally be disabled
Reviewed by: Robert Mustacchi <rm@fingolfin.org>
Change-ID: I7ccd399c22866f34dd20c6bb9d28e77ba4e24c67

@@ -22,12 +22,14 @@
  * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
 /*        All Rights Reserved   */
 
+/*
+ * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ */
 
-
 /*
  * Pseudo Terminal Master Driver.
  *
  * The pseudo-tty subsystem simulates a terminal connection, where the master
  * side represents the terminal and the slave represents the user process's

@@ -519,10 +521,17 @@
                         /*FALLTHROUGH*/
                 case ISPTM:
                         DBG(("ack the UNLKPT/ISPTM\n"));
                         miocack(qp, mp, 0, 0);
                         break;
+                case PTSSTTY:
+                        mutex_enter(&ptmp->pt_lock);
+                        ptmp->pt_state |= PTSTTY;
+                        mutex_exit(&ptmp->pt_lock);
+                        DBG(("ack PTSSTTY\n"));
+                        miocack(qp, mp, 0, 0);
+                        break;
                 case ZONEPT:
                 {
                         zoneid_t z;
                         int error;