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