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;
}

#ifndef NOTE_EOF
# define NOTE_EOF 0
#endif

static void
kqueue_modify (int fd, int oev, int nev)
{
  if ((oev ^ nev) & 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 ^ nev) & 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 (kq_events [i].data == EBADF)
            fd_kill (kq_events [i].ident);
        }
      else
        fd_event (
          kq_events [i].ident,
          kq_events [i].filter == EVFILT_READ ? EV_READ
          : kq_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 (int flags)
{
  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 ev. 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 = kqueue_modify;
  method_poll   = kqueue_poll;

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

Revision:	1.5
Committed:	Sat Nov 3 16:23:59 2007 UTC (18 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+2 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
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 int kq_fd;
38			static struct kevent *kq_changes;
39			static int kq_changemax, kq_changecnt;
40			static struct kevent *kq_events;
41			static int kq_eventmax;
42
43			static void
44			kqueue_change (int fd, int filter, int flags, int fflags)
45			{
46			struct kevent *ke;
47
48			array_needsize (kq_changes, kq_changemax, ++kq_changecnt, );
49
50			ke = &kq_changes [kq_changecnt - 1];
51			memset (ke, 0, sizeof (struct kevent));
52			ke->ident = fd;
53			ke->filter = filter;
54			ke->flags = flags;
55			ke->fflags = fflags;
56			}
57
58	root	1.4	#ifndef NOTE_EOF
59			# define NOTE_EOF 0
60			#endif
61
62	root	1.1	static void
63			kqueue_modify (int fd, int oev, int nev)
64			{
65	root	1.4	if ((oev ^ nev) & EV_READ)
66	root	1.1	{
67			if (nev & EV_READ)
68			kqueue_change (fd, EVFILT_READ, EV_ADD, NOTE_EOF);
69			else
70			kqueue_change (fd, EVFILT_READ, EV_DELETE, 0);
71			}
72
73	root	1.4	if ((oev ^ nev) & EV_WRITE)
74	root	1.1	{
75			if (nev & EV_WRITE)
76			kqueue_change (fd, EVFILT_WRITE, EV_ADD, NOTE_EOF);
77			else
78			kqueue_change (fd, EVFILT_WRITE, EV_DELETE, 0);
79			}
80			}
81
82			static void
83			kqueue_poll (ev_tstamp timeout)
84			{
85			int res, i;
86			struct timespec ts;
87
88			ts.tv_sec = (time_t)timeout;
89			ts.tv_nsec = (long)(timeout - (ev_tstamp)ts.tv_sec) * 1e9;
90			res = kevent (kq_fd, kq_changes, kq_changecnt, kq_events, kq_eventmax, &ts);
91			kq_changecnt = 0;
92
93			if (res < 0)
94			return;
95
96			for (i = 0; i < res; ++i)
97			{
98			if (kq_events [i].flags & EV_ERROR)
99			{
100			/*
101			* Error messages that can happen, when a delete fails.
102			* EBADF happens when the file discriptor has been
103			* closed,
104			* ENOENT when the file discriptor was closed and
105			* then reopened.
106			* EINVAL for some reasons not understood; EINVAL
107			* should not be returned ever; but FreeBSD does :-\
108			* An error is also indicated when a callback deletes
109			* an event we are still processing. In that case
110			* the data field is set to ENOENT.
111			*/
112	root	1.4	if (kq_events [i].data == EBADF)
113			fd_kill (kq_events [i].ident);
114	root	1.1	}
115			else
116	root	1.3	fd_event (
117	root	1.4	kq_events [i].ident,
118			kq_events [i].filter == EVFILT_READ ? EV_READ
119			: kq_events [i].filter == EVFILT_WRITE ? EV_WRITE
120	root	1.1	: 0
121			);
122			}
123
124			if (expect_false (res == kq_eventmax))
125			{
126			free (kq_events);
127			kq_eventmax = array_roundsize (kq_events, kq_eventmax << 1);
128			kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
129			}
130			}
131
132			static void
133	root	1.4	kqueue_init (int flags)
134	root	1.1	{
135	root	1.2	struct kevent ch, ev;
136
137	root	1.1	/* Initalize the kernel queue */
138	root	1.2	if ((kq_fd = kqueue ()) < 0)
139	root	1.1	return;
140
141	root	1.2	/* Check for Mac OS X kqueue bug. */
142			ch.ident = -1;
143			ch.filter = EVFILT_READ;
144			ch.flags = EV_ADD;
145	root	1.1
146			/*
147			* If kqueue works, then kevent will succeed, and it will
148	root	1.4	* stick an error in ev. If kqueue is broken, then
149	root	1.1	* kevent will fail.
150			*/
151	root	1.2	if (kevent (kq_fd, &ch, 1, &ev, 1, 0) != 1
152			\|\| ev.ident != -1
153			\|\| ev.flags != EV_ERROR)
154	root	1.1	{
155			/* detected broken kqueue */
156			close (kq_fd);
157			return;
158			}
159
160			ev_method = EVMETHOD_KQUEUE;
161			method_fudge = 1e-3; /* needed to compensate for kevent returning early */
162	root	1.5	method_modify = kqueue_modify;
163			method_poll = kqueue_poll;
164	root	1.1
165			kq_eventmax = 64; /* intiial number of events receivable per poll */
166			kq_events = malloc (sizeof (struct kevent) * kq_eventmax);
167			}
168