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/cvs/libev/ev_poll.c
Revision: 1.1
Committed: Fri Nov 2 15:56:19 2007 UTC (17 years, 1 month ago) by root
Content type: text/plain
Branch: MAIN
Log Message:
README

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# 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 int epoll_fd = -1;
35
36 static void
37 epoll_modify (int fd, int oev, int nev)
38 {
39 int mode = nev ? oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD : EPOLL_CTL_DEL;
40
41 struct epoll_event ev;
42 ev.data.fd = fd;
43 ev.events =
44 (nev & EV_READ ? EPOLLIN : 0)
45 | (nev & EV_WRITE ? EPOLLOUT : 0);
46
47 epoll_ctl (epoll_fd, mode, fd, &ev);
48 }
49
50 static void
51 epoll_postfork_child (void)
52 {
53 int fd;
54
55 epoll_fd = epoll_create (256);
56 fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);
57
58 /* re-register interest in fds */
59 for (fd = 0; fd < anfdmax; ++fd)
60 if (anfds [fd].events)//D
61 epoll_modify (fd, EV_NONE, anfds [fd].events);
62 }
63
64 static struct epoll_event *events;
65 static int eventmax;
66
67 static void
68 epoll_poll (ev_tstamp timeout)
69 {
70 int eventcnt = epoll_wait (epoll_fd, events, eventmax, ceil (timeout * 1000.));
71 int i;
72
73 if (eventcnt < 0)
74 return;
75
76 for (i = 0; i < eventcnt; ++i)
77 fd_event (
78 events [i].data.fd,
79 (events [i].events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
80 | (events [i].events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0)
81 );
82
83 /* if the receive array was full, increase its size */
84 if (expect_false (eventcnt == eventmax))
85 {
86 free (events);
87 eventmax = array_roundsize (events, eventmax << 1);
88 events = malloc (sizeof (struct epoll_event) * eventmax);
89 }
90 }
91
92 static void
93 epoll_init (int flags)
94 {
95 epoll_fd = epoll_create (256);
96
97 if (epoll_fd < 0)
98 return;
99
100 fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);
101
102 ev_method = EVMETHOD_EPOLL;
103 method_fudge = 1e-3; /* needed to compensate for epoll returning early */
104 method_modify = epoll_modify;
105 method_poll = epoll_poll;
106
107 eventmax = 64; /* intiial number of events receivable per poll */
108 events = malloc (sizeof (struct epoll_event) * eventmax);
109 }
110