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.
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;
107 /** Current array of event descriptors. */
108 static struct epoll_event *events;
109 /** Number of ::events elements that have been populated. */
110 static int events_used;
112 /** Decrement the error count (once per hour).
113 * @param[in] ev Expired timer event (ignored).
116 error_clear(struct Event *ev)
119 timer_del(ev_timer(ev));
122 /** Initialize the epoll engine.
123 * @param[in] max_sockets Maximum number of file descriptors to support.
124 * @return Non-zero on success, or zero on failure.
127 engine_init(int max_sockets)
129 if ((epoll_fd = epoll_create(max_sockets)) < 0) {
130 log_write(LS_SYSTEM, L_WARNING, 0,
131 "epoll() engine cannot initialize: %m");
137 /** Set events for a particular socket.
138 * @param[in] sock Socket to calculate events for.
139 * @param[in] state Current socket state.
140 * @param[in] events User-specified event interest list.
141 * @param[out] evt epoll event structure for socket.
144 set_events(struct Socket *sock, enum SocketState state, unsigned int events, struct epoll_event *evt)
147 assert(0 <= s_fd(sock));
148 memset(evt, 0, sizeof(*evt));
150 evt->data.ptr = sock;
154 evt->events = EPOLLOUT;
159 evt->events = EPOLLIN;
165 switch (events & SOCK_EVENT_MASK) {
169 case SOCK_EVENT_READABLE:
170 evt->events = EPOLLIN;
172 case SOCK_EVENT_WRITABLE:
173 evt->events = EPOLLOUT;
175 case SOCK_EVENT_READABLE|SOCK_EVENT_WRITABLE:
176 evt->events = EPOLLIN|EPOLLOUT;
183 /** Add a socket to the event engine.
184 * @param[in] sock Socket to add to engine.
185 * @return Non-zero on success, or zero on error.
188 engine_add(struct Socket *sock)
190 struct epoll_event evt;
193 Debug((DEBUG_ENGINE, "epoll: Adding socket %d [%p], state %s, to engine",
194 s_fd(sock), sock, state_to_name(s_state(sock))));
195 set_events(sock, s_state(sock), s_events(sock), &evt);
196 if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, s_fd(sock), &evt) < 0) {
197 event_generate(ET_ERROR, sock, errno);
203 /** Handle state transition for a socket.
204 * @param[in] sock Socket changing state.
205 * @param[in] new_state New state for socket.
208 engine_set_state(struct Socket *sock, enum SocketState new_state)
210 struct epoll_event evt;
213 Debug((DEBUG_ENGINE, "epoll: Changing state for socket %p to %s",
214 sock, state_to_name(new_state)));
215 set_events(sock, new_state, s_events(sock), &evt);
216 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
217 event_generate(ET_ERROR, sock, errno);
220 /** Handle change to preferred socket events.
221 * @param[in] sock Socket getting new interest list.
222 * @param[in] new_events New set of interesting events for socket.
225 engine_set_events(struct Socket *sock, unsigned new_events)
227 struct epoll_event evt;
230 Debug((DEBUG_ENGINE, "epoll: Changing event mask for socket %p to [%s]",
231 sock, sock_flags(new_events)));
232 set_events(sock, s_state(sock), new_events, &evt);
233 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
234 event_generate(ET_ERROR, sock, errno);
237 /** Remove a socket from the event engine.
238 * @param[in] sock Socket being destroyed.
241 engine_delete(struct Socket *sock)
246 Debug((DEBUG_ENGINE, "epoll: Deleting socket %d [%p], state %s",
247 s_fd(sock), sock, state_to_name(s_state(sock))));
248 /* Drop any unprocessed events citing this socket. */
249 for (ii = 0; ii < events_used; ii++) {
250 if (events[ii].data.ptr == sock) {
251 events[ii] = events[--events_used];
256 /** Run engine event loop.
257 * @param[in] gen Lists of generators of various types.
260 engine_loop(struct Generators *gen)
262 struct epoll_event *evt;
265 int events_count, tmp, wait, errcode;
267 if ((events_count = feature_int(FEAT_POLLS_PER_LOOP)) < 20)
269 events = MyMalloc(sizeof(events[0]) * events_count);
271 if ((tmp = feature_int(FEAT_POLLS_PER_LOOP)) >= 20 && tmp != events_count) {
272 events = MyRealloc(events, sizeof(events[0]) * tmp);
276 wait = timer_next(gen) ? (timer_next(gen) - CurrentTime) * 1000 : -1;
277 Debug((DEBUG_ENGINE, "epoll: delay: %d (%d) %d", timer_next(gen),
279 events_used = epoll_wait(epoll_fd, events, events_count, wait);
280 CurrentTime = time(0);
282 if (events_used < 0) {
283 if (errno != EINTR) {
284 log_write(LS_SOCKET, L_ERROR, 0, "epoll() error: %m");
286 timer_add(timer_init(&clear_error), error_clear, 0, TT_PERIODIC,
288 else if (errors > EPOLL_ERROR_THRESHOLD)
289 server_restart("too many epoll errors");
294 while (events_used > 0) {
295 evt = &events[--events_used];
296 if (!(sock = evt->data.ptr))
300 "epoll: Checking socket %p (fd %d) state %s, events %s",
301 sock, s_fd(sock), state_to_name(s_state(sock)),
302 sock_flags(s_events(sock))));
304 if (evt->events & EPOLLERR) {
306 codesize = sizeof(errcode);
307 if (getsockopt(s_fd(sock), SOL_SOCKET, SO_ERROR, &errcode,
311 event_generate(ET_ERROR, sock, errcode);
315 } else if (evt->events & EPOLLHUP) {
316 event_generate(ET_EOF, sock, 0);
317 } else switch (s_state(sock)) {
319 if (evt->events & EPOLLOUT) /* connection completed */
320 event_generate(ET_CONNECT, sock, 0);
324 if (evt->events & EPOLLIN) /* incoming connection */
325 event_generate(ET_ACCEPT, sock, 0);
332 if (evt->events & EPOLLIN)
333 event_generate(ET_READ, sock, 0);
334 if (evt->events & EPOLLOUT)
335 event_generate(ET_WRITE, sock, 0);
345 /** Descriptor for epoll event engine. */
346 struct Engine engine_epoll = {