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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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# User Rev Content
1 root 1.1 /*
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