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 int kq_fd;
static struct kevent *kq_changes;
static int kq_changemax, kq_changecnt;
static struct kevent *kq_events;
static int kq_eventmax;

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

  array_needsize (kq_changes, kq_changemax, ++kq_changecnt, );

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

static void
kqueue_modify (int fd, int oev, int nev)
{
  if ((oev ^ new) & EV_READ)
    {
      if (nev & EV_READ)
        kqueue_change (fd, EVFILT_READ, EV_ADD, NOTE_EOF);
      else
        kqueue_change (fd, EVFILT_READ, EV_DELETE, 0);
    }

  if ((oev ^ new) & EV_WRITE)
    {
      if (nev & EV_WRITE)
        kqueue_change (fd, EVFILT_WRITE, EV_ADD, NOTE_EOF);
      else
        kqueue_change (fd, EVFILT_WRITE, EV_DELETE, 0);
    }
}

static void
kqueue_poll (ev_tstamp timeout)
{
  int res, i;
  struct timespec ts;

  ts.tv_sec  = (time_t)timeout;
  ts.tv_nsec = (long)(timeout - (ev_tstamp)ts.tv_sec) * 1e9;
  res = kevent (kq_fd, kq_changes, kq_changecnt, kq_events, kq_eventmax, &ts);
  kq_changecnt = 0;

  if (res < 0)
    return;

  for (i = 0; i < res; ++i)
    {
      if (kq_events [i].flags & EV_ERROR)
        {
          /* 
           * Error messages that can happen, when a delete fails.
           *   EBADF happens when the file discriptor has been
           *   closed,
           *   ENOENT when the file discriptor was closed and
           *   then reopened.
           *   EINVAL for some reasons not understood; EINVAL
           *   should not be returned ever; but FreeBSD does :-\
           * An error is also indicated when a callback deletes
           * an event we are still processing.  In that case
           * the data field is set to ENOENT.
           */
          if (events [i].data == EBADF)
            fd_kill (events [i].ident);
        }
      else
        event (
          events [i].ident,
          events [i].filter == EVFILT_READ ? EV_READ
          : events [i].filter == EVFILT_WRITE ? EV_WRITE
          : 0
        );
    }

  if (expect_false (res == kq_eventmax))
    {
      free (kq_events);
      kq_eventmax = array_roundsize (kq_events, kq_eventmax << 1);
      kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
    }
}

static void
kqueue_init (struct event_base *base)
{
  struct kevent ch, ev;

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

  /* 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 events[0]. If kqueue is broken, then
   * kevent will fail.
   */
  if (kevent (kq_fd, &ch, 1, &ev, 1, 0) != 1
      || ev.ident != -1
      || ev.flags != EV_ERROR)
    {
      /* detected broken kqueue */
      close (kq_fd);
      return;
    }

  ev_method     = EVMETHOD_KQUEUE;
  method_fudge  = 1e-3; /* needed to compensate for kevent returning early */
  method_modify = kq_modify;
  method_poll   = kq_poll;

  kq_eventmax = 64; /* intiial number of events receivable per poll */
  kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
}

Revision:	1.2
Committed:	Fri Nov 2 21:17:30 2007 UTC (16 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+10 -24 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1
2			/*
3			* Copyright 2007 Marc Alexander Lehmann <libev@schmorp.de>
4			* Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
5			* All rights reserved.
6			*
7			* Redistribution and use in source and binary forms, with or without
8			* modification, are permitted provided that the following conditions
9			* are met:
10			*
11			* 1. Redistributions of source code must retain the above copyright
12			* notice, this list of conditions and the following disclaimer.
13			* 2. Redistributions in binary form must reproduce the above copyright
14			* notice, this list of conditions and the following disclaimer in the
15			* documentation and/or other materials provided with the distribution.
16			* 3. The name of the author may not be used to endorse or promote products
17			* derived from this software without specific prior written permission.
18			*
19			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29			*/
30
31			#include <sys/types.h>
32			#include <sys/time.h>
33			#include <sys/queue.h>
34			#include <sys/event.h>
35			#include <string.h>
36			#include <errno.h>
37
38			static int kq_fd;
39			static struct kevent *kq_changes;
40			static int kq_changemax, kq_changecnt;
41			static struct kevent *kq_events;
42			static int kq_eventmax;
43
44			static void
45			kqueue_change (int fd, int filter, int flags, int fflags)
46			{
47			struct kevent *ke;
48
49			array_needsize (kq_changes, kq_changemax, ++kq_changecnt, );
50
51			ke = &kq_changes [kq_changecnt - 1];
52			memset (ke, 0, sizeof (struct kevent));
53			ke->ident = fd;
54			ke->filter = filter;
55			ke->flags = flags;
56			ke->fflags = fflags;
57			}
58
59			static void
60			kqueue_modify (int fd, int oev, int nev)
61			{
62			if ((oev ^ new) & EV_READ)
63			{
64			if (nev & EV_READ)
65			kqueue_change (fd, EVFILT_READ, EV_ADD, NOTE_EOF);
66			else
67			kqueue_change (fd, EVFILT_READ, EV_DELETE, 0);
68			}
69
70			if ((oev ^ new) & EV_WRITE)
71			{
72			if (nev & EV_WRITE)
73			kqueue_change (fd, EVFILT_WRITE, EV_ADD, NOTE_EOF);
74			else
75			kqueue_change (fd, EVFILT_WRITE, EV_DELETE, 0);
76			}
77			}
78
79			static void
80			kqueue_poll (ev_tstamp timeout)
81			{
82			int res, i;
83			struct timespec ts;
84
85			ts.tv_sec = (time_t)timeout;
86			ts.tv_nsec = (long)(timeout - (ev_tstamp)ts.tv_sec) * 1e9;
87			res = kevent (kq_fd, kq_changes, kq_changecnt, kq_events, kq_eventmax, &ts);
88			kq_changecnt = 0;
89
90			if (res < 0)
91			return;
92
93			for (i = 0; i < res; ++i)
94			{
95			if (kq_events [i].flags & EV_ERROR)
96			{
97			/*
98			* Error messages that can happen, when a delete fails.
99			* EBADF happens when the file discriptor has been
100			* closed,
101			* ENOENT when the file discriptor was closed and
102			* then reopened.
103			* EINVAL for some reasons not understood; EINVAL
104			* should not be returned ever; but FreeBSD does :-\
105			* An error is also indicated when a callback deletes
106			* an event we are still processing. In that case
107			* the data field is set to ENOENT.
108			*/
109			if (events [i].data == EBADF)
110			fd_kill (events [i].ident);
111			}
112			else
113			event (
114			events [i].ident,
115			events [i].filter == EVFILT_READ ? EV_READ
116			: events [i].filter == EVFILT_WRITE ? EV_WRITE
117			: 0
118			);
119			}
120
121			if (expect_false (res == kq_eventmax))
122			{
123			free (kq_events);
124			kq_eventmax = array_roundsize (kq_events, kq_eventmax << 1);
125			kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
126			}
127			}
128
129			static void
130			kqueue_init (struct event_base *base)
131			{
132	root	1.2	struct kevent ch, ev;
133
134	root	1.1	/* Initalize the kernel queue */
135	root	1.2	if ((kq_fd = kqueue ()) < 0)
136	root	1.1	return;
137
138	root	1.2	/* Check for Mac OS X kqueue bug. */
139			ch.ident = -1;
140			ch.filter = EVFILT_READ;
141			ch.flags = EV_ADD;
142	root	1.1
143			/*
144			* If kqueue works, then kevent will succeed, and it will
145			* stick an error in events[0]. If kqueue is broken, then
146			* kevent will fail.
147			*/
148	root	1.2	if (kevent (kq_fd, &ch, 1, &ev, 1, 0) != 1
149			\|\| ev.ident != -1
150			\|\| ev.flags != EV_ERROR)
151	root	1.1	{
152			/* detected broken kqueue */
153			close (kq_fd);
154			return;
155			}
156
157			ev_method = EVMETHOD_KQUEUE;
158			method_fudge = 1e-3; /* needed to compensate for kevent returning early */
159			method_modify = kq_modify;
160			method_poll = kq_poll;
161
162			kq_eventmax = 64; /* intiial number of events receivable per poll */
163			kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
164			}
165