/*

 * libev kqueue backend

 *

 * Copyright (c) 2007,2008,2009,2010,2011,2012,2013 Marc Alexander Lehmann <libev@schmorp.de>

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modifica-

 * tion, are permitted provided that the following conditions are met:

 *

 *   1.  Redistributions of source code must retain the above copyright notice,

 *       this list of conditions and the following disclaimer.

 *

 *   2.  Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-

 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO

 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-

 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-

 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * Alternatively, the contents of this file may be used under the terms of

 * the GNU General Public License ("GPL") version 2 or any later version,

 * in which case the provisions of the GPL are applicable instead of

 * the above. If you wish to allow the use of your version of this file

 * only under the terms of the GPL and not to allow others to use your

 * version of this file under the BSD license, indicate your decision

 * by deleting the provisions above and replace them with the notice

 * and other provisions required by the GPL. If you do not delete the

 * provisions above, a recipient may use your version of this file under

 * either the BSD or the GPL.

 */

#include <sys/types.h>

#include <sys/time.h>

#include <sys/event.h>

#include <string.h>

#include <errno.h>

inline_speed

void

kqueue_change (EV_P_ int fd, int filter, int flags, int fflags)

{

  ++kqueue_changecnt;

  array_needsize (struct kevent, kqueue_changes, kqueue_changemax, kqueue_changecnt, EMPTY2);

  EV_SET (&kqueue_changes [kqueue_changecnt - 1], fd, filter, flags, fflags, 0, 0);

}

/* OS X at least needs this */

#ifndef EV_ENABLE

# define EV_ENABLE 0

#endif

#ifndef NOTE_EOF

# define NOTE_EOF 0

#endif

static void

kqueue_modify (EV_P_ int fd, int oev, int nev)

{

  if (oev != nev)

    {

      if (oev & EV_READ)

        kqueue_change (EV_A_ fd, EVFILT_READ , EV_DELETE, 0);

      if (oev & EV_WRITE)

        kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_DELETE, 0);

    }

  /* to detect close/reopen reliably, we have to re-add */

  /* event requests even when oev == nev */

  if (nev & EV_READ)

    kqueue_change (EV_A_ fd, EVFILT_READ , EV_ADD | EV_ENABLE, NOTE_EOF);

  if (nev & EV_WRITE)

    kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_ADD | EV_ENABLE, NOTE_EOF);

}

static void

kqueue_poll (EV_P_ ev_tstamp timeout)

{

  int res, i;

  struct timespec ts;

  /* need to resize so there is enough space for errors */

  if (kqueue_changecnt > kqueue_eventmax)

    {

      ev_free (kqueue_events);

      kqueue_eventmax = array_nextsize (sizeof (struct kevent), kqueue_eventmax, kqueue_changecnt);

      kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);

    }

  EV_RELEASE_CB;

  EV_TS_SET (ts, timeout);

  res = kevent (backend_fd, kqueue_changes, kqueue_changecnt, kqueue_events, kqueue_eventmax, &ts);

  EV_ACQUIRE_CB;

  kqueue_changecnt = 0;

  if (expect_false (res < 0))

    {

      if (errno != EINTR)

        ev_syserr ("(libev) kevent");

      return;

    }

  for (i = 0; i < res; ++i)

    {

      int fd = kqueue_events [i].ident;

      if (expect_false (kqueue_events [i].flags & EV_ERROR))

        {

          int err = kqueue_events [i].data;

          /* we are only interested in errors for fds that we are interested in :) */

          if (anfds [fd].events)

            {

              if (err == ENOENT) /* resubmit changes on ENOENT */

                kqueue_modify (EV_A_ fd, 0, anfds [fd].events);

              else if (err == EBADF) /* on EBADF, we re-check the fd */

                {

                  if (fd_valid (fd))

                    kqueue_modify (EV_A_ fd, 0, anfds [fd].events);

                  else

                    fd_kill (EV_A_ fd);

                }

              else /* on all other errors, we error out on the fd */

                fd_kill (EV_A_ fd);

            }

        }

      else

        fd_event (

          EV_A_

          fd,

          kqueue_events [i].filter == EVFILT_READ ? EV_READ

          : kqueue_events [i].filter == EVFILT_WRITE ? EV_WRITE

          : 0

        );

    }

  if (expect_false (res == kqueue_eventmax))

    {

      ev_free (kqueue_events);

      kqueue_eventmax = array_nextsize (sizeof (struct kevent), kqueue_eventmax, kqueue_eventmax + 1);

      kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);

    }

}

inline_size

int

kqueue_init (EV_P_ int flags)

{

  /* initialize the kernel queue */

  kqueue_fd_pid = getpid ();

  if ((backend_fd = kqueue ()) < 0)

    return 0;

  fcntl (backend_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */

  backend_mintime = 1e-9; /* apparently, they did the right thing in freebsd */

  backend_modify  = kqueue_modify;

  backend_poll    = kqueue_poll;

  kqueue_eventmax = 64; /* initial number of events receivable per poll */

  kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);

  kqueue_changes   = 0;

  kqueue_changemax = 0;

  kqueue_changecnt = 0;

  return EVBACKEND_KQUEUE;

}

inline_size

void

kqueue_destroy (EV_P)

{

  ev_free (kqueue_events);

  ev_free (kqueue_changes);

}

inline_size

void

kqueue_fork (EV_P)

{

  /* some BSD kernels don't just destroy the kqueue itself,

   * but also close the fd, which isn't documented, and

   * impossible to support properly.

   * we remember the pid of the kqueue call and only close

   * the fd if the pid is still the same.

   * this leaks fds on sane kernels, but BSD interfaces are

   * notoriously buggy and rarely get fixed.

   */

  pid_t newpid = getpid ();

  if (newpid == kqueue_fd_pid)

    close (backend_fd);

  kqueue_fd_pid = newpid;

  while ((backend_fd = kqueue ()) < 0)

    ev_syserr ("(libev) kqueue");

  fcntl (backend_fd, F_SETFD, FD_CLOEXEC);

  /* re-register interest in fds */

  fd_rearm_all (EV_A);

}

/* sys/event.h defines EV_ERROR */

#undef EV_ERROR