ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev_epoll.c
(Generate patch)

Comparing libev/ev_epoll.c (file contents):
Revision 1.32 by root, Thu Dec 13 16:52:50 2007 UTC vs.
Revision 1.35 by root, Thu Oct 23 04:56:49 2008 UTC

1/* 1/*
2 * libev epoll fd activity backend 2 * libev epoll fd activity backend
3 * 3 *
4 * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de> 4 * Copyright (c) 2007,2008 Marc Alexander Lehmann <libev@schmorp.de>
5 * All rights reserved. 5 * All rights reserved.
6 * 6 *
7 * Redistribution and use in source and binary forms, with or without 7 * Redistribution and use in source and binary forms, with or without modifica-
8 * modification, are permitted provided that the following conditions are 8 * tion, are permitted provided that the following conditions are met:
9 * met:
10 * 9 *
11 * * Redistributions of source code must retain the above copyright 10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer. 14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
13 * 16 *
14 * * Redistributions in binary form must reproduce the above 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
15 * copyright notice, this list of conditions and the following 18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
16 * disclaimer in the documentation and/or other materials provided 19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
17 * with the distribution. 20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
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 21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Alternatively, the contents of this file may be used under the terms of
29 * the GNU General Public License ("GPL") version 2 or any later version,
30 * in which case the provisions of the GPL are applicable instead of
31 * the above. If you wish to allow the use of your version of this file
32 * only under the terms of the GPL and not to allow others to use your
33 * version of this file under the BSD license, indicate your decision
34 * by deleting the provisions above and replace them with the notice
35 * and other provisions required by the GPL. If you do not delete the
36 * provisions above, a recipient may use your version of this file under
37 * either the BSD or the GPL.
30 */ 38 */
31 39
32/* 40/*
33 * general notes about epoll: 41 * general notes about epoll:
34 * 42 *
… …
47 * epoll_ctl syscalls for common usage patterns. 55 * epoll_ctl syscalls for common usage patterns.
48 */ 56 */
49 57
50#include <sys/epoll.h> 58#include <sys/epoll.h>
51 59
60void inline_size
61unsigned_char_init (unsigned char *base, int count)
62{
63 /* memset might be overkill */
64 while (count--)
65 *base++ = 0;
66}
67
52static void 68static void
53epoll_modify (EV_P_ int fd, int oev, int nev) 69epoll_modify (EV_P_ int fd, int oev, int nev)
54{ 70{
55 struct epoll_event ev; 71 struct epoll_event ev;
72 unsigned char oldmask;
56 73
57 /* 74 /*
58 * we handle EPOLL_CTL_DEL by ignoring it here 75 * we handle EPOLL_CTL_DEL by ignoring it here
59 * on the assumption that the fd is gone anyways 76 * on the assumption that the fd is gone anyways
60 * if that is wrong, we have to handle the spurious 77 * if that is wrong, we have to handle the spurious
61 * event in epoll_poll. 78 * event in epoll_poll.
79 * the fd is later added, we try to ADD it, and, if that
80 * fails, we assume it still has the same eventmask.
62 */ 81 */
63 if (!nev) 82 if (!nev)
64 return; 83 return;
65 84
85 oldmask = anfds [fd].emask;
86 anfds [fd].emask = nev;
87
66 ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */ 88 ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */
67 ev.events = (nev & EV_READ ? EPOLLIN : 0) 89 ev.events = (nev & EV_READ ? EPOLLIN : 0)
68 | (nev & EV_WRITE ? EPOLLOUT : 0); 90 | (nev & EV_WRITE ? EPOLLOUT : 0);
69 91
70 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) 92 if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev)))
71 return; 93 return;
72 94
73 if (expect_true (errno == ENOENT)) 95 if (expect_true (errno == ENOENT))
74 { 96 {
75 /* on ENOENT the fd went away, so try to do the right thing */ 97 /* if ENOENT then the fd went away, so try to do the right thing */
76 if (!nev) 98 if (!nev)
77 return; 99 return;
78 100
79 if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev)) 101 if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev))
80 return; 102 return;
81 } 103 }
82 else if (expect_true (errno == EEXIST)) 104 else if (expect_true (errno == EEXIST))
83 { 105 {
84 /* on EEXIST we ignored a previous DEL */ 106 /* EEXIST means we ignored a previous DEL, but the fd is still active */
107 /* if the kernel mask is the same as the new mask, we assume it hasn't changed */
85 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) 108 if (oldmask == nev || !epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev))
86 return; 109 return;
87 } 110 }
88 111
89 fd_kill (EV_A_ fd); 112 fd_kill (EV_A_ fd);
90} 113}
… …
112 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 135 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
113 int want = anfds [fd].events; 136 int want = anfds [fd].events;
114 137
115 if (expect_false (got & ~want)) 138 if (expect_false (got & ~want))
116 { 139 {
140 anfds [fd].emask = want;
141
117 /* we received an event but are not interested in it, try mod or del */ 142 /* we received an event but are not interested in it, try mod or del */
143 /* I don't think we ever need MOD, but let's handle it anyways */
118 ev->events = (want & EV_READ ? EPOLLIN : 0) 144 ev->events = (want & EV_READ ? EPOLLIN : 0)
119 | (want & EV_WRITE ? EPOLLOUT : 0); 145 | (want & EV_WRITE ? EPOLLOUT : 0);
120 146
121 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev); 147 epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev);
122 } 148 }

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines