8634 epoll fails to wake on certain edge-triggered conditions
8635 epoll should not emit POLLNVAL
8636 recursive epoll should emit EPOLLRDNORM
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>

*** 23,33 ****
  
  
  /*
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
!  * Copyright 2015 Joyent, Inc.
   */
  
  /*
   * Generic vnode operations.
   */
--- 23,33 ----
  
  
  /*
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
!  * Copyright 2017 Joyent, Inc.
   */
  
  /*
   * Generic vnode operations.
   */
*** 414,423 ****
--- 414,434 ----
  /* ARGSUSED */
  int
  fs_poll(vnode_t *vp, short events, int anyyet, short *reventsp,
      struct pollhead **phpp, caller_context_t *ct)
  {
+         /*
+          * Reject all attempts for edge-triggered polling.  These should only
+          * occur when regular files are added to a /dev/poll handle which is in
+          * epoll mode.  The Linux epoll does not allow epoll-ing on regular
+          * files at all, so rejecting EPOLLET requests is congruent with those
+          * expectations.
+          */
+         if (events & POLLET) {
+                 return (EPERM);
+         }
+ 
          *reventsp = 0;
          if (events & POLLIN)
                  *reventsp |= POLLIN;
          if (events & POLLRDNORM)
                  *reventsp |= POLLRDNORM;
*** 425,435 ****
                  *reventsp |= POLLRDBAND;
          if (events & POLLOUT)
                  *reventsp |= POLLOUT;
          if (events & POLLWRBAND)
                  *reventsp |= POLLWRBAND;
!         *phpp = !anyyet && !*reventsp ? &fs_pollhd : (struct pollhead *)NULL;
          return (0);
  }
  
  /*
   * POSIX pathconf() support.
--- 436,454 ----
                  *reventsp |= POLLRDBAND;
          if (events & POLLOUT)
                  *reventsp |= POLLOUT;
          if (events & POLLWRBAND)
                  *reventsp |= POLLWRBAND;
!         /*
!          * Emitting a pollhead without the intention of issuing pollwakeup()
!          * calls against it is a recipe for trouble.  It's only acceptable in
!          * this case since the above logic matches practically all useful
!          * events.
!          */
!         if (*reventsp == 0 && !anyyet) {
!                 *phpp = &fs_pollhd;
!         }
          return (0);
  }
  
  /*
   * POSIX pathconf() support.