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 254
53 #define __NR_epoll_ctl 255
54 #define __NR_epoll_wait 256
55 #elif defined(__ia64__)
56 #define __NR_epoll_create 1243
57 #define __NR_epoll_ctl 1244
58 #define __NR_epoll_wait 1245
59 #elif defined(__x86_64__)
60 #define __NR_epoll_create 214
61 #define __NR_epoll_ctl 233
62 #define __NR_epoll_wait 232
64 #error No system call numbers defined for epoll family.
65 #endif /* cpu types */
66 #endif /* !defined(__NR_epoll_create) */
68 _syscall1(int, epoll_create, int, size)
69 _syscall4(int, epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event *, event)
70 _syscall4(int, epoll_wait, int, epfd, struct epoll_event *, pevents, int, maxevents, int, timeout)
72 #endif /* epoll_create defined as stub */
74 #define EPOLL_ERROR_THRESHOLD 20 /**< after 20 epoll errors, restart */
75 #define ERROR_EXPIRE_TIME 3600 /**< expire errors after an hour */
77 /** File descriptor for epoll pseudo-file. */
79 /** Number of recent epoll errors. */
81 /** Periodic timer to forget errors. */
82 static struct Timer clear_error;
84 /** Decrement the error count (once per hour).
85 * @param[in] ev Expired timer event (ignored).
88 error_clear(struct Event *ev)
91 timer_del(ev_timer(ev));
94 /** Initialize the epoll engine.
95 * @param[in] max_sockets Maximum number of file descriptors to support.
96 * @return Non-zero on success, or zero on failure.
99 engine_init(int max_sockets)
101 if ((epoll_fd = epoll_create(max_sockets)) < 0) {
102 log_write(LS_SYSTEM, L_WARNING, 0,
103 "epoll() engine cannot initialize: %m");
109 /** Set events for a particular socket.
110 * @param[in] sock Socket to calculate events for.
111 * @param[in] state Current socket state.
112 * @param[in] events User-specified event interest list.
113 * @param[out] evt epoll event structure for socket.
116 set_events(struct Socket *sock, enum SocketState state, unsigned int events, struct epoll_event *evt)
119 assert(0 <= s_fd(sock));
120 memset(evt, 0, sizeof(*evt));
122 evt->data.ptr = sock;
126 evt->events = EPOLLOUT;
131 evt->events = EPOLLIN;
137 switch (events & SOCK_EVENT_MASK) {
141 case SOCK_EVENT_READABLE:
142 evt->events = EPOLLIN;
144 case SOCK_EVENT_WRITABLE:
145 evt->events = EPOLLOUT;
147 case SOCK_EVENT_READABLE|SOCK_EVENT_WRITABLE:
148 evt->events = EPOLLIN|EPOLLOUT;
155 /** Add a socket to the event engine.
156 * @param[in] sock Socket to add to engine.
157 * @return Non-zero on success, or zero on error.
160 engine_add(struct Socket *sock)
162 struct epoll_event evt;
165 Debug((DEBUG_ENGINE, "epoll: Adding socket %d [%p], state %s, to engine",
166 s_fd(sock), sock, state_to_name(s_state(sock))));
167 set_events(sock, s_state(sock), s_events(sock), &evt);
168 if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, s_fd(sock), &evt) < 0) {
169 event_generate(ET_ERROR, sock, errno);
175 /** Handle state transition for a socket.
176 * @param[in] sock Socket changing state.
177 * @param[in] new_state New state for socket.
180 engine_set_state(struct Socket *sock, enum SocketState new_state)
182 struct epoll_event evt;
185 Debug((DEBUG_ENGINE, "epoll: Changing state for socket %p to %s",
186 sock, state_to_name(new_state)));
187 set_events(sock, new_state, s_events(sock), &evt);
188 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
189 event_generate(ET_ERROR, sock, errno);
192 /** Handle change to preferred socket events.
193 * @param[in] sock Socket getting new interest list.
194 * @param[in] new_events New set of interesting events for socket.
197 engine_set_events(struct Socket *sock, unsigned new_events)
199 struct epoll_event evt;
202 Debug((DEBUG_ENGINE, "epoll: Changing event mask for socket %p to [%s]",
203 sock, sock_flags(new_events)));
204 set_events(sock, s_state(sock), new_events, &evt);
205 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, s_fd(sock), &evt) < 0)
206 event_generate(ET_ERROR, sock, errno);
209 /** Remove a socket from the event engine.
210 * @param[in] sock Socket being destroyed.
213 engine_delete(struct Socket *sock)
216 Debug((DEBUG_ENGINE, "epoll: Deleting socket %d [%p], state %s",
217 s_fd(sock), sock, state_to_name(s_state(sock))));
218 /* No action necessary; epoll removes the socket on close(). */
221 /** Run engine event loop.
222 * @param[in] gen Lists of generators of various types.
225 engine_loop(struct Generators *gen)
227 struct epoll_event *events;
230 int events_count, i, wait, nevs, errcode;
232 if ((events_count = feature_int(FEAT_POLLS_PER_LOOP)) < 20)
234 events = MyMalloc(sizeof(events[0]) * events_count);
236 if ((i = feature_int(FEAT_POLLS_PER_LOOP)) >= 20 && i != events_count) {
237 events = MyRealloc(events, sizeof(events[0]) * i);
241 wait = timer_next(gen) ? (timer_next(gen) - CurrentTime) * 1000 : -1;
242 Debug((DEBUG_ENGINE, "epoll: delay: %d (%d) %d", timer_next(gen),
244 nevs = epoll_wait(epoll_fd, events, events_count, wait);
245 CurrentTime = time(0);
248 if (errno != EINTR) {
249 log_write(LS_SOCKET, L_ERROR, 0, "epoll() error: %m");
251 timer_add(timer_init(&clear_error), error_clear, 0, TT_PERIODIC,
253 else if (errors > EPOLL_ERROR_THRESHOLD)
254 server_restart("too many epoll errors");
259 for (i = 0; i < nevs; i++) {
260 if (!(sock = events[i].data.ptr))
264 "epoll: Checking socket %p (fd %d) state %s, events %s",
265 sock, s_fd(sock), state_to_name(s_state(sock)),
266 sock_flags(s_events(sock))));
268 if (events[i].events & EPOLLERR) {
270 codesize = sizeof(errcode);
271 if (getsockopt(s_fd(sock), SOL_SOCKET, SO_ERROR, &errcode,
275 event_generate(ET_ERROR, sock, errcode);
281 switch (s_state(sock)) {
283 if (events[i].events & EPOLLOUT) /* connection completed */
284 event_generate(ET_CONNECT, sock, 0);
288 if (events[i].events & EPOLLIN) /* incoming connection */
289 event_generate(ET_ACCEPT, sock, 0);
294 if (events[i].events & EPOLLIN)
295 event_generate((events[i].events & EPOLLHUP) ? ET_EOF : ET_READ, sock, 0);
296 if (events[i].events & EPOLLOUT)
297 event_generate(ET_WRITE, sock, 0);
302 if (events[i].events & EPOLLIN)
303 event_generate(ET_READ, sock, 0);
304 if (events[i].events & EPOLLOUT)
305 event_generate(ET_WRITE, sock, 0);
315 /** Descriptor for epoll event engine. */
316 struct Engine engine_epoll = {