libev/ev_epoll.c

/*
 * libev epoll fd activity backend
 *
 * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 COPYRIGHT
 * OWNER OR CONTRIBUTORS 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/epoll.h>

static void
epoll_modify (EV_P_ int fd, int oev, int nev)
{
  int mode = nev ? oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD : EPOLL_CTL_DEL;

  struct epoll_event ev;
  ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */
  ev.events =
      (nev & EV_READ ? EPOLLIN : 0)
      | (nev & EV_WRITE ? EPOLLOUT : 0);

  if (epoll_ctl (epoll_fd, mode, fd, &ev))
    if (errno != ENOENT /* on ENOENT the fd went away, so try to do the right thing */
        || (nev && epoll_ctl (epoll_fd, EPOLL_CTL_ADD, fd, &ev)))
      fd_kill (EV_A_ fd);
}

static void
epoll_poll (EV_P_ ev_tstamp timeout)
{
  int i;
  int eventcnt = epoll_wait (epoll_fd, epoll_events, epoll_eventmax, ceil (timeout * 1000.));

  if (eventcnt < 0)
    {
      if (errno != EINTR)
        syserr ("(libev) epoll_wait");

      return;
    }

  for (i = 0; i < eventcnt; ++i)
    fd_event (
      EV_A_
      epoll_events [i].data.u64,
      (epoll_events [i].events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
      | (epoll_events [i].events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0)
    );

  /* if the receive array was full, increase its size */
  if (expect_false (eventcnt == epoll_eventmax))
    {
      ev_free (epoll_events);
      epoll_eventmax = array_roundsize (epoll_events, epoll_eventmax << 1);
      epoll_events = ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
    }
}

static int
epoll_init (EV_P_ int flags)
{
  epoll_fd = epoll_create (256);

  if (epoll_fd < 0)
    return 0;

  fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);

  method_fudge  = 1e-3; /* needed to compensate for epoll returning early */
  method_modify = epoll_modify;
  method_poll   = epoll_poll;

  epoll_eventmax = 64; /* intiial number of events receivable per poll */
  epoll_events = ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);

  return EVMETHOD_EPOLL;
}

static void
epoll_destroy (EV_P)
{
  close (epoll_fd);

  ev_free (epoll_events);
}

static void
epoll_fork (EV_P)
{
  close (epoll_fd);

  while ((epoll_fd = epoll_create (256)) < 0)
    syserr ("(libev) epoll_create");

  fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);

  fd_rearm_all (EV_A);
}

Revision:	1.22
Committed:	Tue Nov 6 01:17:16 2007 UTC (16 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-0_5
Changes since 1.21:	+3 -8 lines
Log Message:	better fork
#	Content
1	/*
2	* libev epoll fd activity backend
3	*
4	* Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
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 are
9	* met:
10	*
11	* * Redistributions of source code must retain the above copyright
12	* notice, this list of conditions and the following disclaimer.
13	*
14	* * Redistributions in binary form must reproduce the above
15	* copyright notice, this list of conditions and the following
16	* disclaimer in the documentation and/or other materials provided
17	* with the distribution.
18	*
19	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30	*/
31
32	#include <sys/epoll.h>
33
34	static void
35	epoll_modify (EV_P_ int fd, int oev, int nev)
36	{
37	int mode = nev ? oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD : EPOLL_CTL_DEL;
38
39	struct epoll_event ev;
40	ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */
41	ev.events =
42	(nev & EV_READ ? EPOLLIN : 0)
43	\| (nev & EV_WRITE ? EPOLLOUT : 0);
44
45	if (epoll_ctl (epoll_fd, mode, fd, &ev))
46	if (errno != ENOENT /* on ENOENT the fd went away, so try to do the right thing */
47	\|\| (nev && epoll_ctl (epoll_fd, EPOLL_CTL_ADD, fd, &ev)))
48	fd_kill (EV_A_ fd);
49	}
50
51	static void
52	epoll_poll (EV_P_ ev_tstamp timeout)
53	{
54	int i;
55	int eventcnt = epoll_wait (epoll_fd, epoll_events, epoll_eventmax, ceil (timeout * 1000.));
56
57	if (eventcnt < 0)
58	{
59	if (errno != EINTR)
60	syserr ("(libev) epoll_wait");
61
62	return;
63	}
64
65	for (i = 0; i < eventcnt; ++i)
66	fd_event (
67	EV_A_
68	epoll_events [i].data.u64,
69	(epoll_events [i].events & (EPOLLOUT \| EPOLLERR \| EPOLLHUP) ? EV_WRITE : 0)
70	\| (epoll_events [i].events & (EPOLLIN \| EPOLLERR \| EPOLLHUP) ? EV_READ : 0)
71	);
72
73	/* if the receive array was full, increase its size */
74	if (expect_false (eventcnt == epoll_eventmax))
75	{
76	ev_free (epoll_events);
77	epoll_eventmax = array_roundsize (epoll_events, epoll_eventmax << 1);
78	epoll_events = ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
79	}
80	}
81
82	static int
83	epoll_init (EV_P_ int flags)
84	{
85	epoll_fd = epoll_create (256);
86
87	if (epoll_fd < 0)
88	return 0;
89
90	fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);
91
92	method_fudge = 1e-3; /* needed to compensate for epoll returning early */
93	method_modify = epoll_modify;
94	method_poll = epoll_poll;
95
96	epoll_eventmax = 64; /* intiial number of events receivable per poll */
97	epoll_events = ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
98
99	return EVMETHOD_EPOLL;
100	}
101
102	static void
103	epoll_destroy (EV_P)
104	{
105	close (epoll_fd);
106
107	ev_free (epoll_events);
108	}
109
110	static void
111	epoll_fork (EV_P)
112	{
113	close (epoll_fd);
114
115	while ((epoll_fd = epoll_create (256)) < 0)
116	syserr ("(libev) epoll_create");
117
118	fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);
119
120	fd_rearm_all (EV_A);
121	}
122