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1 | /* | |
2 | * IRC - Internet Relay Chat, ircd/engine_kqueue.c | |
3 | * Copyright (C) 2001 Kevin L. Mitchell <klmitch@mit.edu> | |
4 | * | |
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) | |
8 | * any later version. | |
9 | * | |
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. | |
14 | * | |
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. | |
18 | */ | |
19 | /** @file | |
20 | * @brief FreeBSD kqueue()/kevent() event engine. | |
21 | * @version $Id: engine_kqueue.c,v 1.8 2005/03/23 00:25:16 entrope Exp $ | |
22 | */ | |
23 | #include "config.h" | |
24 | ||
25 | #include "ircd_events.h" | |
26 | ||
27 | #include "ircd.h" | |
28 | #include "ircd_alloc.h" | |
29 | #include "ircd_features.h" | |
30 | #include "ircd_log.h" | |
31 | #include "s_debug.h" | |
32 | ||
33 | /* #include <assert.h> -- Now using assert in ircd_log.h */ | |
34 | #include <errno.h> | |
35 | #include <signal.h> | |
36 | #include <sys/types.h> | |
37 | #include <sys/event.h> | |
38 | #include <sys/socket.h> | |
39 | #include <sys/time.h> | |
40 | #include <time.h> | |
41 | #include <unistd.h> | |
42 | ||
43 | #define KQUEUE_ERROR_THRESHOLD 20 /**< after 20 kqueue errors, restart */ | |
44 | #define ERROR_EXPIRE_TIME 3600 /**< expire errors after an hour */ | |
45 | ||
46 | /** Array of active Socket structures, indexed by file descriptor. */ | |
47 | static struct Socket** sockList; | |
48 | /** Maximum file descriptor supported, plus one. */ | |
49 | static int kqueue_max; | |
50 | /** File descriptor for kqueue pseudo-file. */ | |
51 | static int kqueue_id; | |
52 | ||
53 | /** Number of recent errors from kqueue. */ | |
54 | static int errors = 0; | |
55 | /** Periodic timer to forget errors. */ | |
56 | static struct Timer clear_error; | |
57 | ||
58 | /** Decrement the error count (once per hour). | |
59 | * @param[in] ev Expired timer event (ignored). | |
60 | */ | |
61 | static void | |
62 | error_clear(struct Event* ev) | |
63 | { | |
64 | if (!--errors) /* remove timer when error count reaches 0 */ | |
65 | timer_del(ev_timer(ev)); | |
66 | } | |
67 | ||
68 | /** Initialize the kqueue engine. | |
69 | * @param[in] max_sockets Maximum number of file descriptors to support. | |
70 | * @return Non-zero on success, or zero on failure. | |
71 | */ | |
72 | static int | |
73 | engine_init(int max_sockets) | |
74 | { | |
75 | int i; | |
76 | ||
77 | if ((kqueue_id = kqueue()) < 0) { /* initialize... */ | |
78 | log_write(LS_SYSTEM, L_WARNING, 0, | |
79 | "kqueue() engine cannot initialize: %m"); | |
80 | return 0; | |
81 | } | |
82 | ||
83 | /* allocate necessary memory */ | |
84 | sockList = (struct Socket**) MyMalloc(sizeof(struct Socket*) * max_sockets); | |
85 | ||
86 | /* initialize the data */ | |
87 | for (i = 0; i < max_sockets; i++) | |
88 | sockList[i] = 0; | |
89 | ||
90 | kqueue_max = max_sockets; /* number of sockets allocated */ | |
91 | ||
92 | return 1; /* success! */ | |
93 | } | |
94 | ||
95 | /** Add a signal to the event engine. | |
96 | * @param[in] sig Signal to add to engine. | |
97 | */ | |
98 | static void | |
99 | engine_signal(struct Signal* sig) | |
100 | { | |
101 | struct kevent sigevent; | |
102 | struct sigaction act; | |
103 | ||
104 | assert(0 != signal); | |
105 | ||
106 | Debug((DEBUG_ENGINE, "kqueue: Adding filter for signal %d [%p]", | |
107 | sig_signal(sig), sig)); | |
108 | ||
109 | sigevent.ident = sig_signal(sig); /* set up the kqueue event */ | |
110 | sigevent.filter = EVFILT_SIGNAL; /* looking for signals... */ | |
111 | sigevent.flags = EV_ADD | EV_ENABLE; /* add and enable it */ | |
112 | sigevent.fflags = 0; | |
113 | sigevent.data = 0; | |
114 | sigevent.udata = sig; /* store our user data */ | |
115 | ||
116 | if (kevent(kqueue_id, &sigevent, 1, 0, 0, 0) < 0) { /* add event */ | |
117 | log_write(LS_SYSTEM, L_WARNING, 0, "Unable to trap signal %d", | |
118 | sig_signal(sig)); | |
119 | return; | |
120 | } | |
121 | ||
122 | act.sa_handler = SIG_IGN; /* ignore the signal */ | |
123 | act.sa_flags = 0; | |
124 | sigemptyset(&act.sa_mask); | |
125 | sigaction(sig_signal(sig), &act, 0); | |
126 | } | |
127 | ||
128 | /** Figure out what events go with a given state. | |
129 | * @param[in] state %Socket state to consider. | |
130 | * @param[in] events User-specified preferred event set. | |
131 | * @return Actual set of preferred events. | |
132 | */ | |
133 | static unsigned int | |
134 | state_to_events(enum SocketState state, unsigned int events) | |
135 | { | |
136 | switch (state) { | |
137 | case SS_CONNECTING: /* connecting socket */ | |
138 | return SOCK_EVENT_WRITABLE; | |
139 | break; | |
140 | ||
141 | case SS_LISTENING: /* listening socket */ | |
142 | case SS_NOTSOCK: /* our signal socket--just in case */ | |
143 | return SOCK_EVENT_READABLE; | |
144 | break; | |
145 | ||
146 | case SS_CONNECTED: case SS_DATAGRAM: case SS_CONNECTDG: | |
147 | return events; /* ordinary socket */ | |
148 | break; | |
149 | } | |
150 | ||
151 | /*NOTREACHED*/ | |
152 | return 0; | |
153 | } | |
154 | ||
155 | /** Activate kqueue filters as appropriate. | |
156 | * @param[in] sock Socket structure to operate on. | |
157 | * @param[in] clear Set of interest events to clear from socket. | |
158 | * @param[in] set Set of interest events to set on socket. | |
159 | */ | |
160 | static void | |
161 | set_or_clear(struct Socket* sock, unsigned int clear, unsigned int set) | |
162 | { | |
163 | int i = 0; | |
164 | struct kevent chglist[2]; | |
165 | ||
166 | assert(0 != sock); | |
167 | assert(-1 < s_fd(sock)); | |
168 | ||
169 | if ((clear ^ set) & SOCK_EVENT_READABLE) { /* readable has changed */ | |
170 | chglist[i].ident = s_fd(sock); /* set up the change list */ | |
171 | chglist[i].filter = EVFILT_READ; /* readable filter */ | |
172 | chglist[i].flags = EV_ADD; /* adding it */ | |
173 | chglist[i].fflags = 0; | |
174 | chglist[i].data = 0; | |
175 | chglist[i].udata = 0; /* I love udata, but it can't really be used here */ | |
176 | ||
177 | if (set & SOCK_EVENT_READABLE) /* it's set */ | |
178 | chglist[i].flags |= EV_ENABLE; | |
179 | else /* clear it */ | |
180 | chglist[i].flags |= EV_DISABLE; | |
181 | ||
182 | i++; /* advance to next element */ | |
183 | } | |
184 | ||
185 | if ((clear ^ set) & SOCK_EVENT_WRITABLE) { /* writable has changed */ | |
186 | chglist[i].ident = s_fd(sock); /* set up the change list */ | |
187 | chglist[i].filter = EVFILT_WRITE; /* writable filter */ | |
188 | chglist[i].flags = EV_ADD; /* adding it */ | |
189 | chglist[i].fflags = 0; | |
190 | chglist[i].data = 0; | |
191 | chglist[i].udata = 0; | |
192 | ||
193 | if (set & SOCK_EVENT_WRITABLE) /* it's set */ | |
194 | chglist[i].flags |= EV_ENABLE; | |
195 | else /* clear it */ | |
196 | chglist[i].flags |= EV_DISABLE; | |
197 | ||
198 | i++; /* advance count... */ | |
199 | } | |
200 | ||
201 | if (kevent(kqueue_id, chglist, i, 0, 0, 0) < 0 && errno != EBADF) | |
202 | event_generate(ET_ERROR, sock, errno); /* report error */ | |
203 | } | |
204 | ||
205 | /** Add a socket to the event engine. | |
206 | * @param[in] sock Socket to add to engine. | |
207 | * @return Non-zero on success, or zero on error. | |
208 | */ | |
209 | static int | |
210 | engine_add(struct Socket* sock) | |
211 | { | |
212 | assert(0 != sock); | |
213 | assert(0 == sockList[s_fd(sock)]); | |
214 | ||
215 | /* bounds-check... */ | |
216 | if (sock->s_fd >= kqueue_max) { | |
217 | log_write(LS_SYSTEM, L_ERROR, 0, | |
218 | "Attempt to add socket %d (> %d) to event engine", s_fd(sock), | |
219 | kqueue_max); | |
220 | return 0; | |
221 | } | |
222 | ||
223 | sockList[s_fd(sock)] = sock; /* add to list */ | |
224 | ||
225 | Debug((DEBUG_ENGINE, "kqueue: Adding socket %d [%p], state %s, to engine", | |
226 | s_fd(sock), sock, state_to_name(s_state(sock)))); | |
227 | ||
228 | /* Add socket to queue */ | |
229 | set_or_clear(sock, 0, state_to_events(s_state(sock), s_events(sock))); | |
230 | ||
231 | return 1; /* success */ | |
232 | } | |
233 | ||
234 | /** Handle state transition for a socket. | |
235 | * @param[in] sock Socket changing state. | |
236 | * @param[in] new_state New state for socket. | |
237 | */ | |
238 | static void | |
239 | engine_state(struct Socket* sock, enum SocketState new_state) | |
240 | { | |
241 | assert(0 != sock); | |
242 | assert(sock == sockList[s_fd(sock)]); | |
243 | ||
244 | Debug((DEBUG_ENGINE, "kqueue: Changing state for socket %p to %s", sock, | |
245 | state_to_name(new_state))); | |
246 | ||
247 | /* set the correct events */ | |
248 | set_or_clear(sock, | |
249 | state_to_events(s_state(sock), s_events(sock)), /* old state */ | |
250 | state_to_events(new_state, s_events(sock))); /* new state */ | |
251 | ||
252 | } | |
253 | ||
254 | /** Handle change to preferred socket events. | |
255 | * @param[in] sock Socket getting new interest list. | |
256 | * @param[in] new_events New set of interesting events for socket. | |
257 | */ | |
258 | static void | |
259 | engine_events(struct Socket* sock, unsigned int new_events) | |
260 | { | |
261 | assert(0 != sock); | |
262 | assert(sock == sockList[s_fd(sock)]); | |
263 | ||
264 | Debug((DEBUG_ENGINE, "kqueue: Changing event mask for socket %p to [%s]", | |
265 | sock, sock_flags(new_events))); | |
266 | ||
267 | /* set the correct events */ | |
268 | set_or_clear(sock, | |
269 | state_to_events(s_state(sock), s_events(sock)), /* old events */ | |
270 | state_to_events(s_state(sock), new_events)); /* new events */ | |
271 | } | |
272 | ||
273 | /** Remove a socket from the event engine. | |
274 | * @param[in] sock Socket being destroyed. | |
275 | */ | |
276 | static void | |
277 | engine_delete(struct Socket* sock) | |
278 | { | |
279 | struct kevent dellist[2]; | |
280 | ||
281 | assert(0 != sock); | |
282 | assert(sock == sockList[s_fd(sock)]); | |
283 | ||
284 | Debug((DEBUG_ENGINE, "kqueue: Deleting socket %d [%p], state %s", | |
285 | s_fd(sock), sock, state_to_name(s_state(sock)))); | |
286 | ||
287 | dellist[0].ident = s_fd(sock); /* set up the delete list */ | |
288 | dellist[0].filter = EVFILT_READ; /* readable filter */ | |
289 | dellist[0].flags = EV_DELETE; /* delete it */ | |
290 | dellist[0].fflags = 0; | |
291 | dellist[0].data = 0; | |
292 | dellist[0].udata = 0; | |
293 | ||
294 | dellist[1].ident = s_fd(sock); | |
295 | dellist[1].filter = EVFILT_WRITE; /* writable filter */ | |
296 | dellist[1].flags = EV_DELETE; /* delete it */ | |
297 | dellist[1].fflags = 0; | |
298 | dellist[1].data = 0; | |
299 | dellist[1].udata = 0; | |
300 | ||
301 | sockList[s_fd(sock)] = 0; | |
302 | } | |
303 | ||
304 | /** Run engine event loop. | |
305 | * @param[in] gen Lists of generators of various types. | |
306 | */ | |
307 | static void | |
308 | engine_loop(struct Generators* gen) | |
309 | { | |
310 | struct kevent *events; | |
311 | int events_count; | |
312 | struct Socket* sock; | |
313 | struct timespec wait; | |
314 | int nevs; | |
315 | int i; | |
316 | int errcode; | |
317 | size_t codesize; | |
318 | ||
319 | if ((events_count = feature_int(FEAT_POLLS_PER_LOOP)) < 20) | |
320 | events_count = 20; | |
321 | events = (struct kevent *)MyMalloc(sizeof(struct kevent) * events_count); | |
322 | ||
323 | while (running) { | |
324 | if ((i = feature_int(FEAT_POLLS_PER_LOOP)) >= 20 && i != events_count) { | |
325 | events = (struct kevent *)MyRealloc(events, sizeof(struct kevent) * i); | |
326 | events_count = i; | |
327 | } | |
328 | ||
329 | /* set up the sleep time */ | |
330 | wait.tv_sec = timer_next(gen) ? (timer_next(gen) - CurrentTime) : -1; | |
331 | wait.tv_nsec = 0; | |
332 | ||
333 | Debug((DEBUG_INFO, "kqueue: delay: %Tu (%Tu) %Tu", timer_next(gen), | |
334 | CurrentTime, wait.tv_sec)); | |
335 | ||
336 | /* check for active events */ | |
337 | nevs = kevent(kqueue_id, 0, 0, events, events_count, | |
338 | wait.tv_sec < 0 ? 0 : &wait); | |
339 | ||
340 | CurrentTime = time(0); /* set current time... */ | |
341 | ||
342 | if (nevs < 0) { | |
343 | if (errno != EINTR) { /* ignore kevent interrupts */ | |
344 | /* Log the kqueue error */ | |
345 | log_write(LS_SOCKET, L_ERROR, 0, "kevent() error: %m"); | |
346 | if (!errors++) | |
347 | timer_add(timer_init(&clear_error), error_clear, 0, TT_PERIODIC, | |
348 | ERROR_EXPIRE_TIME); | |
349 | else if (errors > KQUEUE_ERROR_THRESHOLD) /* too many errors... */ | |
350 | server_restart("too many kevent errors"); | |
351 | } | |
352 | /* old code did a sleep(1) here; with usage these days, | |
353 | * that may be too expensive | |
354 | */ | |
355 | continue; | |
356 | } | |
357 | ||
358 | for (i = 0; i < nevs; i++) { | |
359 | if (events[i].filter == EVFILT_SIGNAL) { | |
360 | /* it's a signal; deal appropriately */ | |
361 | event_generate(ET_SIGNAL, events[i].udata, events[i].ident); | |
362 | continue; /* skip socket processing loop */ | |
363 | } | |
364 | ||
365 | assert(events[i].filter == EVFILT_READ || | |
366 | events[i].filter == EVFILT_WRITE); | |
367 | ||
368 | sock = sockList[events[i].ident]; | |
369 | if (!sock) /* slots may become empty while processing events */ | |
370 | continue; | |
371 | ||
372 | assert(s_fd(sock) == events[i].ident); | |
373 | ||
374 | gen_ref_inc(sock); /* can't have it going away on us */ | |
375 | ||
376 | Debug((DEBUG_ENGINE, "kqueue: Checking socket %p (fd %d) state %s, " | |
377 | "events %s", sock, s_fd(sock), state_to_name(s_state(sock)), | |
378 | sock_flags(s_events(sock)))); | |
379 | ||
380 | if (s_state(sock) != SS_NOTSOCK) { | |
381 | errcode = 0; /* check for errors on socket */ | |
382 | codesize = sizeof(errcode); | |
383 | if (getsockopt(s_fd(sock), SOL_SOCKET, SO_ERROR, &errcode, | |
384 | &codesize) < 0) | |
385 | errcode = errno; /* work around Solaris implementation */ | |
386 | ||
387 | if (errcode) { /* an error occurred; generate an event */ | |
388 | Debug((DEBUG_ENGINE, "kqueue: Error %d on fd %d, socket %p", errcode, | |
389 | s_fd(sock), sock)); | |
390 | event_generate(ET_ERROR, sock, errcode); | |
391 | gen_ref_dec(sock); /* careful not to leak reference counts */ | |
392 | continue; | |
393 | } | |
394 | } | |
395 | ||
396 | switch (s_state(sock)) { | |
397 | case SS_CONNECTING: | |
398 | if (events[i].filter == EVFILT_WRITE) { /* connection completed */ | |
399 | Debug((DEBUG_ENGINE, "kqueue: Connection completed")); | |
400 | event_generate(ET_CONNECT, sock, 0); | |
401 | } | |
402 | break; | |
403 | ||
404 | case SS_LISTENING: | |
405 | if (events[i].filter == EVFILT_READ) { /* connect. to be accept. */ | |
406 | Debug((DEBUG_ENGINE, "kqueue: Ready for accept")); | |
407 | event_generate(ET_ACCEPT, sock, 0); | |
408 | } | |
409 | break; | |
410 | ||
411 | case SS_NOTSOCK: /* doing nothing socket-specific */ | |
412 | case SS_CONNECTED: | |
413 | if (events[i].filter == EVFILT_READ) { /* data on socket */ | |
414 | Debug((DEBUG_ENGINE, "kqueue: EOF or data to be read")); | |
415 | event_generate(events[i].flags & EV_EOF ? ET_EOF : ET_READ, sock, 0); | |
416 | } | |
417 | if (events[i].filter == EVFILT_WRITE) { /* socket writable */ | |
418 | Debug((DEBUG_ENGINE, "kqueue: Data can be written")); | |
419 | event_generate(ET_WRITE, sock, 0); | |
420 | } | |
421 | break; | |
422 | ||
423 | case SS_DATAGRAM: case SS_CONNECTDG: | |
424 | if (events[i].filter == EVFILT_READ) { /* socket readable */ | |
425 | Debug((DEBUG_ENGINE, "kqueue: Datagram to be read")); | |
426 | event_generate(ET_READ, sock, 0); | |
427 | } | |
428 | if (events[i].filter == EVFILT_WRITE) { /* socket writable */ | |
429 | Debug((DEBUG_ENGINE, "kqueue: Datagram can be written")); | |
430 | event_generate(ET_WRITE, sock, 0); | |
431 | } | |
432 | break; | |
433 | } | |
434 | ||
435 | gen_ref_dec(sock); /* we're done with it */ | |
436 | } | |
437 | ||
438 | timer_run(); /* execute any pending timers */ | |
439 | } | |
440 | } | |
441 | ||
442 | /** Descriptor for kqueue() event engine. */ | |
443 | struct Engine engine_kqueue = { | |
444 | "kqueue()", /* Engine name */ | |
445 | engine_init, /* Engine initialization function */ | |
446 | engine_signal, /* Engine signal registration function */ | |
447 | engine_add, /* Engine socket registration function */ | |
448 | engine_state, /* Engine socket state change function */ | |
449 | engine_events, /* Engine socket events mask function */ | |
450 | engine_delete, /* Engine socket deletion function */ | |
451 | engine_loop /* Core engine event loop */ | |
452 | }; |