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)
{
  /* to detect close/reopen reliably, we have to remove and re-add */
  /* event requests even when 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);

  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;
    }

  method_fudge  = 1e-3; /* needed to compensate for kevent returning early */
  method_modify = kqueue_modify;
  method_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:	1.20
Committed:	Fri Nov 23 05:00:45 2007 UTC (16 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.19:	+1 -1 lines
Log Message:	renamed METHODs to BACKENDs add ev_supported_backends and ev_recommended_backends functions.
#	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	/* to detect close/reopen reliably, we have to remove and re-add */
61	/* event requests even when oev == nev */
62
63	if (oev & EV_READ)
64	kqueue_change (EV_A_ fd, EVFILT_READ, EV_DELETE, 0);
65
66	if (oev & EV_WRITE)
67	kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_DELETE, 0);
68
69	if (nev & EV_READ)
70	kqueue_change (EV_A_ fd, EVFILT_READ, EV_ADD, NOTE_EOF);
71
72	if (nev & EV_WRITE)
73	kqueue_change (EV_A_ fd, EVFILT_WRITE, EV_ADD, NOTE_EOF);
74	}
75
76	static void
77	kqueue_poll (EV_P_ ev_tstamp timeout)
78	{
79	int res, i;
80	struct timespec ts;
81
82	/* need to resize so there is enough space for errors */
83	if (kqueue_changecnt > kqueue_eventmax)
84	{
85	ev_free (kqueue_events);
86	kqueue_eventmax = array_roundsize (struct kevent, kqueue_changecnt);
87	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
88	}
89
90	ts.tv_sec = (time_t)timeout;
91	ts.tv_nsec = (long)((timeout - (ev_tstamp)ts.tv_sec) * 1e9);
92	res = kevent (kqueue_fd, kqueue_changes, kqueue_changecnt, kqueue_events, kqueue_eventmax, &ts);
93	kqueue_changecnt = 0;
94
95	if (res < 0)
96	{
97	if (errno != EINTR)
98	syserr ("(libev) kevent");
99
100	return;
101	}
102
103	for (i = 0; i < res; ++i)
104	{
105	int fd = kqueue_events [i].ident;
106
107	if (kqueue_events [i].flags & EV_ERROR)
108	{
109	int err = kqueue_events [i].data;
110
111	/*
112	* errors that may happen
113	* EBADF happens when the file discriptor has been
114	* closed,
115	* ENOENT when the file descriptor was closed and
116	* then reopened.
117	* EINVAL for some reasons not understood; EINVAL
118	* should not be returned ever; but FreeBSD does :-\
119	*/
120
121	/* we are only interested in errors for fds that we are interested in :) */
122	if (anfds [fd].events)
123	{
124	if (err == ENOENT) /* resubmit changes on ENOENT */
125	kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
126	else if (err == EBADF) /* on EBADF, we re-check the fd */
127	{
128	if (fd_valid (fd))
129	kqueue_modify (EV_A_ fd, 0, anfds [fd].events);
130	else
131	fd_kill (EV_A_ fd);
132	}
133	else /* on all other errors, we error out on the fd */
134	fd_kill (EV_A_ fd);
135	}
136	}
137	else
138	fd_event (
139	EV_A_
140	fd,
141	kqueue_events [i].filter == EVFILT_READ ? EV_READ
142	: kqueue_events [i].filter == EVFILT_WRITE ? EV_WRITE
143	: 0
144	);
145	}
146
147	if (expect_false (res == kqueue_eventmax))
148	{
149	ev_free (kqueue_events);
150	kqueue_eventmax = array_roundsize (struct kevent, kqueue_eventmax << 1);
151	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
152	}
153	}
154
155	static int
156	kqueue_init (EV_P_ int flags)
157	{
158	struct kevent ch, ev;
159
160	/* Initalize the kernel queue */
161	if ((kqueue_fd = kqueue ()) < 0)
162	return 0;
163
164	fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC); /* not sure if necessary, hopefully doesn't hurt */
165
166	/* Check for Mac OS X kqueue bug. */
167	ch.ident = -1;
168	ch.filter = EVFILT_READ;
169	ch.flags = EV_ADD;
170
171	/*
172	* If kqueue works, then kevent will succeed, and it will
173	* stick an error in ev. If kqueue is broken, then
174	* kevent will fail.
175	*/
176	if (kevent (kqueue_fd, &ch, 1, &ev, 1, 0) != 1
177	\|\| ev.ident != -1
178	\|\| ev.flags != EV_ERROR)
179	{
180	/* detected broken kqueue */
181	close (kqueue_fd);
182	return 0;
183	}
184
185	method_fudge = 1e-3; /* needed to compensate for kevent returning early */
186	method_modify = kqueue_modify;
187	method_poll = kqueue_poll;
188
189	kqueue_eventmax = 64; /* intiial number of events receivable per poll */
190	kqueue_events = (struct kevent )ev_malloc (sizeof (struct kevent) kqueue_eventmax);
191
192	kqueue_changes = 0;
193	kqueue_changemax = 0;
194	kqueue_changecnt = 0;
195
196	return EVBACKEND_KQUEUE;
197	}
198
199	static void
200	kqueue_destroy (EV_P)
201	{
202	close (kqueue_fd);
203
204	ev_free (kqueue_events);
205	ev_free (kqueue_changes);
206	}
207
208	static void
209	kqueue_fork (EV_P)
210	{
211	close (kqueue_fd);
212
213	while ((kqueue_fd = kqueue ()) < 0)
214	syserr ("(libev) kqueue");
215
216	fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC);
217
218	/* re-register interest in fds */
219	fd_rearm_all (EV_A);
220	}
221