2 * IRC - Internet Relay Chat, ircd/engine_epoll.c
3 * Copyright (C) 2003 Michael Poole <mdpoole@troilus.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 1, or (at your option)
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 * @brief Linux epoll_*() event engine.
21 * @version $Id: engine_epoll.c 1463 2005-08-25 01:26:46Z entrope $
26 #include "ircd_events.h"
27 #include "ircd_alloc.h"
28 #include "ircd_features.h"
32 /* #include <assert.h> -- Now using assert in ircd_log.h */
34 #include <sys/types.h>
36 #include <stdint.h> /* bah */
39 #include <sys/epoll.h>
40 #include <sys/socket.h>
42 #include <linux/unistd.h>
44 /* The GNU C library may have a valid header but stub implementations
45 * of the epoll system calls. If so, provide our own. */
46 #if defined(__stub_epoll_create) || defined(__stub___epoll_create) || defined(EPOLL_NEED_BODY)
48 /* Oh, did we mention that some glibc releases do not even define the
50 #if !defined(__NR_epoll_create)
52 #define __NR_epoll_create 1243
53 #define __NR_epoll_ctl 1244
54 #define __NR_epoll_wait 1245
55 #elif defined(__x86_64__)
56 #define __NR_epoll_create 214
57 #define __NR_epoll_ctl 233
58 #define __NR_epoll_wait 232
59 #elif defined(__sparc64__) || defined(__sparc__)
60 #define __NR_epoll_create 193
61 #define __NR_epoll_ctl 194
62 #define __NR_epoll_wait 195
63 #elif defined(__s390__) || defined(__m68k__)
64 #define __NR_epoll_create 249
65 #define __NR_epoll_ctl 250
66 #define __NR_epoll_wait 251
67 #elif defined(__ppc64__) || defined(__ppc__)
68 #define __NR_epoll_create 236
69 #define __NR_epoll_ctl 237
70 #define __NR_epoll_wait 238
71 #elif defined(__parisc__) || defined(__arm26__) || defined(__arm__)
72 #define __NR_epoll_create 224
73 #define __NR_epoll_ctl 225
74 #define __NR_epoll_wait 226
75 #elif defined(__alpha__)
76 #define __NR_epoll_create 407
77 #define __NR_epoll_ctl 408
78 #define __NR_epoll_wait 409
79 #elif defined(__sh64__)
80 #define __NR_epoll_create 282
81 #define __NR_epoll_ctl 283
82 #define __NR_epoll_wait 284
83 #elif defined(__i386__) || defined(__sh__) || defined(__m32r__) || defined(__h8300__) || defined(__frv__)
84 #define __NR_epoll_create 254
85 #define __NR_epoll_ctl 255
86 #define __NR_epoll_wait 256
88 #error No system call numbers defined for epoll family.
89 #endif /* cpu types */
90 #endif /* !defined(__NR_epoll_create) */
92 _syscall1(int, epoll_create, int, size)
93 _syscall4(int, epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event *, event)
94 _syscall4(int, epoll_wait, int, epfd, struct epoll_event *, pevents, int, maxevents, int, timeout)
96 #endif /* epoll_create defined as stub */
98 #define EPOLL_ERROR_THRESHOLD 20 /**< after 20 epoll errors, restart */
99 #define ERROR_EXPIRE_TIME 3600 /**< expire errors after an hour */
101 /** File descriptor for epoll pseudo-file. */
103 /** Number of recent epoll errors. */
105 /** Periodic timer to forget errors. */
106 static struct Timer clear_error;
108 /** Decrement the error count (once per hour).
109 * @param[in] ev Expired timer event (ignored).
112 error_clear(struct Event *ev)
115 timer_del(ev_timer(ev));
118 /** Initialize the epoll engine.
119 * @param[in] max_sockets Maximum number of file descriptors to support.
120 * @return Non-zero on success, or zero on failure.
123 engine_init(int max_sockets)
125 if ((epoll_fd = epoll_create(max_sockets)) < 0) {
126 log_write(LS_SYSTEM, L_WARNING, 0,
127 "epoll() engine cannot initialize: %m");
133 /** Set events for a particular socket.
134 * @param[in] sock Socket to calculate events for.
135 * @param[in] state Current socket state.
136 * @param[in] events User-specified event interest list.
137 * @param[out] evt epoll event structure for socket.
140 set_events(struct Socket *sock, enum SocketState state, unsigned int events, struct epoll_event *evt)
143 assert(0 <= s_fd(sock));
144 memset(evt, 0, sizeof(*evt));
146 evt->data.ptr = sock;
150 evt->events = EPOLLOUT;
155 evt->events = EPOLLIN;
161 switch (events & SOCK_EVENT_MASK) {
165 case SOCK_EVENT_READABLE:
166 evt->events = EPOLLIN;
168 case SOCK_EVENT_WRITABLE:
169 evt->events = EPOLLOUT;
171 case SOCK_EVENT_READABLE|SOCK_EVENT_WRITABLE:
172 evt->events = EPOLLIN|EPOLLOUT;
179 /** Add a socket to the event engine.
180 * @param[in] sock Socket to add to engine.
181 * @return Non-zero on success, or zero on error.
184 engine_add(struct Socket *sock)
186 struct epoll_event evt;
189 Debug((DEBUG_ENGINE, "epoll: Adding socket %d [%p], state %s, to engine",
190 s_fd(sock), sock, state_to_name(s_state(sock))));
191 set_events(sock, s_state(sock), s_events(sock), &evt);
192 if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, s_fd(sock), &evt) < 0) {
193 /* epoll mysteriously occasionally returns errno-17 here if the
194 * client uses OpenSSL. Seems to be an epoll bug because other
195 * polling mechanism don't show this behaviour.
196 * We just ignore errno 17 here.
199 if(errno == 17) return 1;
200 event_generate(ET_ERROR, sock, errno);
206 /** Handle state transition for a socket.
207 * @param[in] sock Socket changing state.
208 * @param[in] new_state New state for socket.
211 engine_set_state(struct Socket *sock, enum SocketState new_state)
213 struct epoll_event evt;
216 Debug((DEBUG_ENGINE, "epoll: Changing state for socket %p to %s",
217 sock, state_to_name(new_state)));
218 set_events(sock, new_state, s_events(sock), &evt);
219 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
220 event_generate(ET_ERROR, sock, errno);
223 /** Handle change to preferred socket events.
224 * @param[in] sock Socket getting new interest list.
225 * @param[in] new_events New set of interesting events for socket.
228 engine_set_events(struct Socket *sock, unsigned new_events)
230 struct epoll_event evt;
233 Debug((DEBUG_ENGINE, "epoll: Changing event mask for socket %p to [%s]",
234 sock, sock_flags(new_events)));
235 set_events(sock, s_state(sock), new_events, &evt);
236 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
237 event_generate(ET_ERROR, sock, errno);
240 /** Remove a socket from the event engine.
241 * @param[in] sock Socket being destroyed.
244 engine_delete(struct Socket *sock)
247 Debug((DEBUG_ENGINE, "epoll: Deleting socket %d [%p], state %s",
248 s_fd(sock), sock, state_to_name(s_state(sock))));
249 /* No action necessary; epoll removes the socket on close(). */
252 /** Run engine event loop.
253 * @param[in] gen Lists of generators of various types.
256 engine_loop(struct Generators *gen)
258 struct epoll_event *events;
261 int events_count, i, wait, nevs, errcode;
263 if ((events_count = feature_int(FEAT_POLLS_PER_LOOP)) < 20)
265 events = MyMalloc(sizeof(events[0]) * events_count);
267 if ((i = feature_int(FEAT_POLLS_PER_LOOP)) >= 20 && i != events_count) {
268 events = MyRealloc(events, sizeof(events[0]) * i);
272 wait = timer_next(gen) ? (timer_next(gen) - CurrentTime) * 1000 : -1;
273 Debug((DEBUG_ENGINE, "epoll: delay: %d (%d) %d", timer_next(gen),
275 nevs = epoll_wait(epoll_fd, events, events_count, wait);
276 CurrentTime = time(0);
279 if (errno != EINTR) {
280 log_write(LS_SOCKET, L_ERROR, 0, "epoll() error: %m");
282 timer_add(timer_init(&clear_error), error_clear, 0, TT_PERIODIC,
284 else if (errors > EPOLL_ERROR_THRESHOLD)
285 server_restart("too many epoll errors");
290 for (i = 0; i < nevs; i++) {
291 if (!(sock = events[i].data.ptr))
295 "epoll: Checking socket %p (fd %d) state %s, events %s",
296 sock, s_fd(sock), state_to_name(s_state(sock)),
297 sock_flags(s_events(sock))));
299 if (events[i].events & EPOLLERR) {
301 codesize = sizeof(errcode);
302 if (getsockopt(s_fd(sock), SOL_SOCKET, SO_ERROR, &errcode,
306 event_generate(ET_ERROR, sock, errcode);
310 } else if (events[i].events & EPOLLHUP) {
311 event_generate(ET_EOF, sock, 0);
312 } else switch (s_state(sock)) {
314 if (events[i].events & EPOLLOUT) /* connection completed */
315 event_generate(ET_CONNECT, sock, 0);
319 if (events[i].events & EPOLLIN) /* incoming connection */
320 event_generate(ET_ACCEPT, sock, 0);
327 if (events[i].events & EPOLLIN)
328 event_generate(ET_READ, sock, 0);
329 if (events[i].events & EPOLLOUT)
330 event_generate(ET_WRITE, sock, 0);
340 /** Descriptor for epoll event engine. */
341 struct Engine engine_epoll = {