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Comparing libev/ev_epoll.c (file contents):
Revision 1.52 by sf-exg, Sat Jul 31 23:00:11 2010 UTC vs.
Revision 1.56 by root, Wed Jan 5 04:25:12 2011 UTC

1/* 1/*
2 * libev epoll fd activity backend 2 * libev epoll fd activity backend
3 * 3 *
4 * Copyright (c) 2007,2008,2009,2010 Marc Alexander Lehmann <libev@schmorp.de> 4 * Copyright (c) 2007,2008,2009,2010,2011 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 modifica- 7 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met: 8 * tion, are permitted provided that the following conditions are met:
9 * 9 *
… …
51 * poll replacement. 51 * poll replacement.
52 * d) epoll doesn't work the same as select with many file descriptors 52 * d) epoll doesn't work the same as select with many file descriptors
53 * (such as files). while not critical, no other advanced interface 53 * (such as files). while not critical, no other advanced interface
54 * seems to share this (rather non-unixy) limitation. 54 * seems to share this (rather non-unixy) limitation.
55 * e) epoll claims to be embeddable, but in practise you never get 55 * e) epoll claims to be embeddable, but in practise you never get
56 * a ready event for the epoll fd. 56 * a ready event for the epoll fd (broken: <=2.6.26, working: >=2.6.32).
57 * f) epoll_ctl returning EPERM means the fd is always ready.
57 * 58 *
58 * lots of "weird code" and complication handling in this file is due 59 * lots of "weird code" and complication handling in this file is due
59 * to these design problems with epoll, as we try very hard to avoid 60 * to these design problems with epoll, as we try very hard to avoid
60 * epoll_ctl syscalls for common usage patterns and handle the breakage 61 * epoll_ctl syscalls for common usage patterns and handle the breakage
61 * ensuing from receiving events for closed and otherwise long gone 62 * ensuing from receiving events for closed and otherwise long gone
62 * file descriptors. 63 * file descriptors.
63 */ 64 */
64 65
65#include <sys/epoll.h> 66#include <sys/epoll.h>
67
68#define EV_EMASK_EPERM 0x80
66 69
67static void 70static void
68epoll_modify (EV_P_ int fd, int oev, int nev) 71epoll_modify (EV_P_ int fd, int oev, int nev)
69{ 72{
70 struct epoll_event ev; 73 struct epoll_event ev;
… …
110 goto dec_egen; 113 goto dec_egen;
111 114
112 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) 115 if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev))
113 return; 116 return;
114 } 117 }
118 else if (expect_true (errno == EPERM))
119 {
120 anfds [fd].emask = EV_EMASK_EPERM;
121
122 /* add fd to epoll_eperms, if not already inside */
123 if (!(oldmask & EV_EMASK_EPERM))
124 {
125 array_needsize (int, epoll_eperms, epoll_epermmax, epoll_epermcnt + 1, EMPTY2);
126 epoll_eperms [epoll_epermcnt++] = fd;
127 }
128
129 return;
130 }
115 131
116 fd_kill (EV_A_ fd); 132 fd_kill (EV_A_ fd);
117 133
118dec_egen: 134dec_egen:
119 /* we didn't successfully call epoll_ctl, so decrement the generation counter again */ 135 /* we didn't successfully call epoll_ctl, so decrement the generation counter again */
… …
148 int want = anfds [fd].events; 164 int want = anfds [fd].events;
149 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) 165 int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0)
150 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); 166 | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0);
151 167
152 /* check for spurious notification */ 168 /* check for spurious notification */
169 /* we assume that fd is always in range, as we never shrink the anfds array */
153 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32))) 170 if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32)))
154 { 171 {
155 /* recreate kernel state */ 172 /* recreate kernel state */
156 postfork = 1; 173 postfork = 1;
157 continue; 174 continue;
… …
183 { 200 {
184 ev_free (epoll_events); 201 ev_free (epoll_events);
185 epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1); 202 epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1);
186 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); 203 epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax);
187 } 204 }
205
206 /* now synthesize events for all fds where epoll fails, while select works... */
207 for (i = epoll_epermcnt; i--; )
208 {
209 int fd = epoll_eperms [i];
210 unsigned char events = anfds [fd].events & (EV_READ | EV_WRITE);
211
212 if (anfds [fd].emask & EV_EMASK_EPERM && events)
213 fd_event (EV_A_ fd, events);
214 else
215 epoll_eperms [i] = epoll_eperms [--epoll_epermcnt];
216 }
188} 217}
189 218
190int inline_size 219int inline_size
191epoll_init (EV_P_ int flags) 220epoll_init (EV_P_ int flags)
192{ 221{
… …
214 243
215void inline_size 244void inline_size
216epoll_destroy (EV_P) 245epoll_destroy (EV_P)
217{ 246{
218 ev_free (epoll_events); 247 ev_free (epoll_events);
248 array_free (epoll_eperm, EMPTY);
219} 249}
220 250
221void inline_size 251void inline_size
222epoll_fork (EV_P) 252epoll_fork (EV_P)
223{ 253{

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