libev/ev_kqueue.c

/*
 * Copyright 2007      Marc Alexander Lehmann <libev@schmorp.de>
 * Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, 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 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <string.h>
#include <errno.h>

static void
kqueue_change (EV_P_ int fd, int filter, int flags, int fflags)
{
  struct kevent *ke;

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

  ke = &kqueue_changes [kqueue_changecnt - 1];
  memset (ke, 0, sizeof (struct kevent));
  ke->ident  = fd;
  ke->filter = filter;
  ke->flags  = flags;
  ke->fflags = fflags;
}

#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, NOTE_EOF);

  if (nev & EV_WRITE)
    kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_ADD, 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_roundsize (struct kevent, kqueue_changecnt);
      kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);
    }

  ts.tv_sec  = (time_t)timeout;
  ts.tv_nsec = (long)((timeout - (ev_tstamp)ts.tv_sec) * 1e9);
  res = kevent (kqueue_fd, kqueue_changes, kqueue_changecnt, kqueue_events, kqueue_eventmax, &ts);
  kqueue_changecnt = 0;

  if (res < 0)
    { 
      if (errno != EINTR)
        syserr ("(libev) kevent");

      return;
    } 

  for (i = 0; i < res; ++i)
    {
      int fd = kqueue_events [i].ident;

      if (kqueue_events [i].flags & EV_ERROR)
        {
          int err = kqueue_events [i].data;

          /* 
           * errors that may happen
           *   EBADF happens when the file discriptor has been
           *   closed,
           *   ENOENT when the file descriptor was closed and
           *   then reopened.
           *   EINVAL for some reasons not understood; EINVAL
           *   should not be returned ever; but FreeBSD does :-\
           */

          /* 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_roundsize (struct kevent, kqueue_eventmax << 1);
      kqueue_events = (struct kevent *)ev_malloc (sizeof (struct kevent) * kqueue_eventmax);
    }
}

static int
kqueue_init (EV_P_ int flags)
{
  struct kevent ch, ev;

  /* Initalize the kernel queue */
  if ((kqueue_fd = kqueue ()) < 0)
    return 0;

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

  /* Check for Mac OS X kqueue bug. */
  ch.ident  = -1;
  ch.filter = EVFILT_READ;
  ch.flags  = EV_ADD;

  /* 
   * If kqueue works, then kevent will succeed, and it will
   * stick an error in ev. If kqueue is broken, then
   * kevent will fail.
   */
  if (kevent (kqueue_fd, &ch, 1, &ev, 1, 0) != 1
      || ev.ident != -1
      || ev.flags != EV_ERROR)
    {
      /* detected broken kqueue */
      close (kqueue_fd);
      return 0;
    }

  backend_fudge  = 1e-3; /* needed to compensate for kevent returning early */
  backend_modify = kqueue_modify;
  backend_poll   = kqueue_poll;

  kqueue_eventmax = 64; /* intiial 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;
}

static void
kqueue_destroy (EV_P)
{
  close (kqueue_fd);

  ev_free (kqueue_events);
  ev_free (kqueue_changes);
}

static void
kqueue_fork (EV_P)
{
  close (kqueue_fd);

  while ((kqueue_fd = kqueue ()) < 0)
    syserr ("(libev) kqueue");

  fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC);

  /* re-register interest in fds */
  fd_rearm_all (EV_A);
}

Revision:	1.22
Committed:	Fri Nov 23 05:28:17 2007 UTC (16 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.21:	+10 -7 lines
Log Message:	minor kqueue optimisation
#	Content
1	/*
2	* Copyright 2007 Marc Alexander Lehmann <libev@schmorp.de>
3	* Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
4	* All rights reserved.
5	*
6	* Redistribution and use in source and binary forms, with or without
7	* modification, are permitted provided that the following conditions
8	* are met:
9	*
10	* 1. Redistributions of source code must retain the above copyright
11	* notice, this list of conditions and the following disclaimer.
12	* 2. Redistributions in binary form must reproduce the above copyright
13	* notice, this list of conditions and the following disclaimer in the
14	* documentation and/or other materials provided with the distribution.
15	* 3. The name of the author may not be used to endorse or promote products
16	* derived from this software without specific prior written permission.
17	*
18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28	*/
29
30	#include <sys/types.h>
31	#include <sys/time.h>
32	#include <sys/queue.h>
33	#include <sys/event.h>
34	#include <string.h>
35	#include <errno.h>
36
37	static void
38	kqueue_change (EV_P_ int fd, int filter, int flags, int fflags)
39	{
40	struct kevent *ke;
41
42	++kqueue_changecnt;
43	array_needsize (struct kevent, kqueue_changes, kqueue_changemax, kqueue_changecnt, EMPTY2);
44
45	ke = &kqueue_changes [kqueue_changecnt - 1];
46	memset (ke, 0, sizeof (struct kevent));
47	ke->ident = fd;
48	ke->filter = filter;
49	ke->flags = flags;
50	ke->fflags = fflags;
51	}
52
53	#ifndef NOTE_EOF
54	# define NOTE_EOF 0
55	#endif
56
57	static void
58	kqueue_modify (EV_P_ int fd, int oev, int nev)
59	{
60	if (oev != nev)
61	{
62	if (oev & EV_READ)
63	kqueue_change (EV_A_ fd, EVFILT_READ , EV_DELETE, 0);
64
65	if (oev & EV_WRITE)
66	kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_DELETE, 0);
67	}
68
69	/* to detect close/reopen reliably, we have to re-add */
70	/* event requests even when oev == nev */
71
72	if (nev & EV_READ)
73	kqueue_change (EV_A_ fd, EVFILT_READ , EV_ADD, NOTE_EOF);
74
75	if (nev & EV_WRITE)
76	kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_ADD, NOTE_EOF);
77	}
78
79	static void
80	kqueue_poll (EV_P_ ev_tstamp timeout)
81	{
82	int res, i;
83	struct timespec ts;
84
85	/* need to resize so there is enough space for errors */
86	if (kqueue_changecnt > kqueue_eventmax)
87	{
88	ev_free (kqueue_events);
89	kqueue_eventmax = array_roundsize (struct kevent, kqueue_changecnt);
90	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
91	}
92
93	ts.tv_sec = (time_t)timeout;
94	ts.tv_nsec = (long)((timeout - (ev_tstamp)ts.tv_sec) * 1e9);
95	res = kevent (kqueue_fd, kqueue_changes, kqueue_changecnt, kqueue_events, kqueue_eventmax, &ts);
96	kqueue_changecnt = 0;
97
98	if (res < 0)
99	{
100	if (errno != EINTR)
101	syserr ("(libev) kevent");
102
103	return;
104	}
105
106	for (i = 0; i < res; ++i)
107	{
108	int fd = kqueue_events [i].ident;
109
110	if (kqueue_events [i].flags & EV_ERROR)
111	{
112	int err = kqueue_events [i].data;
113
114	/*
115	* errors that may happen
116	* EBADF happens when the file discriptor has been
117	* closed,
118	* ENOENT when the file descriptor was closed and
119	* then reopened.
120	* EINVAL for some reasons not understood; EINVAL
121	* should not be returned ever; but FreeBSD does :-\
122	*/
123
124	/* we are only interested in errors for fds that we are interested in :) */
125	if (anfds [fd].events)
126	{
127	if (err == ENOENT) /* resubmit changes on ENOENT */
128	kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
129	else if (err == EBADF) /* on EBADF, we re-check the fd */
130	{
131	if (fd_valid (fd))
132	kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
133	else
134	fd_kill (EV_A_ fd);
135	}
136	else /* on all other errors, we error out on the fd */
137	fd_kill (EV_A_ fd);
138	}
139	}
140	else
141	fd_event (
142	EV_A_
143	fd,
144	kqueue_events [i].filter == EVFILT_READ ? EV_READ
145	: kqueue_events [i].filter == EVFILT_WRITE ? EV_WRITE
146	: 0
147	);
148	}
149
150	if (expect_false (res == kqueue_eventmax))
151	{
152	ev_free (kqueue_events);
153	kqueue_eventmax = array_roundsize (struct kevent, kqueue_eventmax << 1);
154	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
155	}
156	}
157
158	static int
159	kqueue_init (EV_P_ int flags)
160	{
161	struct kevent ch, ev;
162
163	/* Initalize the kernel queue */
164	if ((kqueue_fd = kqueue ()) < 0)
165	return 0;
166
167	fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */
168
169	/* Check for Mac OS X kqueue bug. */
170	ch.ident = -1;
171	ch.filter = EVFILT_READ;
172	ch.flags = EV_ADD;
173
174	/*
175	* If kqueue works, then kevent will succeed, and it will
176	* stick an error in ev. If kqueue is broken, then
177	* kevent will fail.
178	*/
179	if (kevent (kqueue_fd, &ch, 1, &ev, 1, 0) != 1
180	\|\| ev.ident != -1
181	\|\| ev.flags != EV_ERROR)
182	{
183	/* detected broken kqueue */
184	close (kqueue_fd);
185	return 0;
186	}
187
188	backend_fudge = 1e-3; /* needed to compensate for kevent returning early */
189	backend_modify = kqueue_modify;
190	backend_poll = kqueue_poll;
191
192	kqueue_eventmax = 64; /* intiial number of events receivable per poll */
193	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
194
195	kqueue_changes = 0;
196	kqueue_changemax = 0;
197	kqueue_changecnt = 0;
198
199	return EVBACKEND_KQUEUE;
200	}
201
202	static void
203	kqueue_destroy (EV_P)
204	{
205	close (kqueue_fd);
206
207	ev_free (kqueue_events);
208	ev_free (kqueue_changes);
209	}
210
211	static void
212	kqueue_fork (EV_P)
213	{
214	close (kqueue_fd);
215
216	while ((kqueue_fd = kqueue ()) < 0)
217	syserr ("(libev) kqueue");
218
219	fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC);
220
221	/* re-register interest in fds */
222	fd_rearm_all (EV_A);
223	}
224