xref: /netbsd-src/external/mpl/dhcp/bind/dist/lib/isc/timer.c (revision 4afad4b7fa6d4a0d3dedf41d1587a7250710ae54)
1 /*	$NetBSD: timer.c,v 1.1 2024/02/18 20:57:50 christos Exp $	*/
2 
3 /*
4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
5  *
6  * SPDX-License-Identifier: MPL-2.0
7  *
8  * This Source Code Form is subject to the terms of the Mozilla Public
9  * License, v. 2.0. If a copy of the MPL was not distributed with this
10  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
11  *
12  * See the COPYRIGHT file distributed with this work for additional
13  * information regarding copyright ownership.
14  */
15 
16 /*! \file */
17 
18 #include <stdbool.h>
19 
20 #include <isc/app.h>
21 #include <isc/condition.h>
22 #include <isc/heap.h>
23 #include <isc/log.h>
24 #include <isc/magic.h>
25 #include <isc/mem.h>
26 #include <isc/once.h>
27 #include <isc/platform.h>
28 #include <isc/print.h>
29 #include <isc/refcount.h>
30 #include <isc/task.h>
31 #include <isc/thread.h>
32 #include <isc/time.h>
33 #include <isc/timer.h>
34 #include <isc/util.h>
35 
36 #ifdef OPENSSL_LEAKS
37 #include <openssl/err.h>
38 #endif /* ifdef OPENSSL_LEAKS */
39 
40 #ifdef ISC_TIMER_TRACE
41 #define XTRACE(s)      fprintf(stderr, "%s\n", (s))
42 #define XTRACEID(s, t) fprintf(stderr, "%s %p\n", (s), (t))
43 #define XTRACETIME(s, d) \
44 	fprintf(stderr, "%s %u.%09u\n", (s), (d).seconds, (d).nanoseconds)
45 #define XTRACETIME2(s, d, n)                                      \
46 	fprintf(stderr, "%s %u.%09u %u.%09u\n", (s), (d).seconds, \
47 		(d).nanoseconds, (n).seconds, (n).nanoseconds)
48 #define XTRACETIMER(s, t, d)                                      \
49 	fprintf(stderr, "%s %p %u.%09u\n", (s), (t), (d).seconds, \
50 		(d).nanoseconds)
51 #else /* ifdef ISC_TIMER_TRACE */
52 #define XTRACE(s)
53 #define XTRACEID(s, t)
54 #define XTRACETIME(s, d)
55 #define XTRACETIME2(s, d, n)
56 #define XTRACETIMER(s, t, d)
57 #endif /* ISC_TIMER_TRACE */
58 
59 #define TIMER_MAGIC    ISC_MAGIC('T', 'I', 'M', 'R')
60 #define VALID_TIMER(t) ISC_MAGIC_VALID(t, TIMER_MAGIC)
61 
62 struct isc_timer {
63 	/*! Not locked. */
64 	unsigned int magic;
65 	isc_timermgr_t *manager;
66 	isc_mutex_t lock;
67 	/*! Locked by timer lock. */
68 	isc_time_t idle;
69 	ISC_LIST(isc_timerevent_t) active;
70 	/*! Locked by manager lock. */
71 	isc_timertype_t type;
72 	isc_time_t expires;
73 	isc_interval_t interval;
74 	isc_task_t *task;
75 	isc_taskaction_t action;
76 	void *arg;
77 	unsigned int index;
78 	isc_time_t due;
79 	LINK(isc_timer_t) link;
80 };
81 
82 #define TIMER_MANAGER_MAGIC ISC_MAGIC('T', 'I', 'M', 'M')
83 #define VALID_MANAGER(m)    ISC_MAGIC_VALID(m, TIMER_MANAGER_MAGIC)
84 
85 struct isc_timermgr {
86 	/* Not locked. */
87 	unsigned int magic;
88 	isc_mem_t *mctx;
89 	isc_mutex_t lock;
90 	/* Locked by manager lock. */
91 	bool done;
92 	LIST(isc_timer_t) timers;
93 	unsigned int nscheduled;
94 	isc_time_t due;
95 	isc_condition_t wakeup;
96 	isc_thread_t thread;
97 	isc_heap_t *heap;
98 };
99 
100 void
101 isc_timermgr_poke(isc_timermgr_t *manager0);
102 
103 static isc_result_t
schedule(isc_timer_t * timer,isc_time_t * now,bool signal_ok)104 schedule(isc_timer_t *timer, isc_time_t *now, bool signal_ok) {
105 	isc_timermgr_t *manager;
106 	isc_time_t due;
107 	int cmp;
108 
109 	/*!
110 	 * Note: the caller must ensure locking.
111 	 */
112 
113 	REQUIRE(timer->type != isc_timertype_inactive);
114 
115 	manager = timer->manager;
116 
117 	/*
118 	 * Compute the new due time.
119 	 */
120 	if (timer->type != isc_timertype_once) {
121 		isc_result_t result = isc_time_add(now, &timer->interval, &due);
122 		if (result != ISC_R_SUCCESS) {
123 			return (result);
124 		}
125 		if (timer->type == isc_timertype_limited &&
126 		    isc_time_compare(&timer->expires, &due) < 0)
127 		{
128 			due = timer->expires;
129 		}
130 	} else {
131 		if (isc_time_isepoch(&timer->idle)) {
132 			due = timer->expires;
133 		} else if (isc_time_isepoch(&timer->expires)) {
134 			due = timer->idle;
135 		} else if (isc_time_compare(&timer->idle, &timer->expires) < 0)
136 		{
137 			due = timer->idle;
138 		} else {
139 			due = timer->expires;
140 		}
141 	}
142 
143 	/*
144 	 * Schedule the timer.
145 	 */
146 
147 	if (timer->index > 0) {
148 		/*
149 		 * Already scheduled.
150 		 */
151 		cmp = isc_time_compare(&due, &timer->due);
152 		timer->due = due;
153 		switch (cmp) {
154 		case -1:
155 			isc_heap_increased(manager->heap, timer->index);
156 			break;
157 		case 1:
158 			isc_heap_decreased(manager->heap, timer->index);
159 			break;
160 		case 0:
161 			/* Nothing to do. */
162 			break;
163 		}
164 	} else {
165 		timer->due = due;
166 		isc_heap_insert(manager->heap, timer);
167 		manager->nscheduled++;
168 	}
169 
170 	XTRACETIMER("schedule", timer, due);
171 
172 	/*
173 	 * If this timer is at the head of the queue, we need to ensure
174 	 * that we won't miss it if it has a more recent due time than
175 	 * the current "next" timer.  We do this either by waking up the
176 	 * run thread, or explicitly setting the value in the manager.
177 	 */
178 
179 	if (timer->index == 1 && signal_ok) {
180 		XTRACE("signal (schedule)");
181 		SIGNAL(&manager->wakeup);
182 	}
183 
184 	return (ISC_R_SUCCESS);
185 }
186 
187 static void
deschedule(isc_timer_t * timer)188 deschedule(isc_timer_t *timer) {
189 	bool need_wakeup = false;
190 	isc_timermgr_t *manager;
191 
192 	/*
193 	 * The caller must ensure locking.
194 	 */
195 
196 	manager = timer->manager;
197 	if (timer->index > 0) {
198 		if (timer->index == 1) {
199 			need_wakeup = true;
200 		}
201 		isc_heap_delete(manager->heap, timer->index);
202 		timer->index = 0;
203 		INSIST(manager->nscheduled > 0);
204 		manager->nscheduled--;
205 		if (need_wakeup) {
206 			XTRACE("signal (deschedule)");
207 			SIGNAL(&manager->wakeup);
208 		}
209 	}
210 }
211 
212 static void
timerevent_unlink(isc_timer_t * timer,isc_timerevent_t * event)213 timerevent_unlink(isc_timer_t *timer, isc_timerevent_t *event) {
214 	REQUIRE(ISC_LINK_LINKED(event, ev_timerlink));
215 	ISC_LIST_UNLINK(timer->active, event, ev_timerlink);
216 }
217 
218 static void
timerevent_destroy(isc_event_t * event0)219 timerevent_destroy(isc_event_t *event0) {
220 	isc_timer_t *timer = event0->ev_destroy_arg;
221 	isc_timerevent_t *event = (isc_timerevent_t *)event0;
222 
223 	LOCK(&timer->lock);
224 	if (ISC_LINK_LINKED(event, ev_timerlink)) {
225 		/* The event was unlinked via timer_purge() */
226 		timerevent_unlink(timer, event);
227 	}
228 	UNLOCK(&timer->lock);
229 
230 	isc_mem_put(timer->manager->mctx, event, event0->ev_size);
231 }
232 
233 static void
timer_purge(isc_timer_t * timer)234 timer_purge(isc_timer_t *timer) {
235 	isc_timerevent_t *event = NULL;
236 
237 	while ((event = ISC_LIST_HEAD(timer->active)) != NULL) {
238 		timerevent_unlink(timer, event);
239 		UNLOCK(&timer->lock);
240 		(void)isc_task_purgeevent(timer->task, (isc_event_t *)event);
241 		LOCK(&timer->lock);
242 	}
243 }
244 
245 isc_result_t
isc_timer_create(isc_timermgr_t * manager,isc_timertype_t type,const isc_time_t * expires,const isc_interval_t * interval,isc_task_t * task,isc_taskaction_t action,void * arg,isc_timer_t ** timerp)246 isc_timer_create(isc_timermgr_t *manager, isc_timertype_t type,
247 		 const isc_time_t *expires, const isc_interval_t *interval,
248 		 isc_task_t *task, isc_taskaction_t action, void *arg,
249 		 isc_timer_t **timerp) {
250 	REQUIRE(VALID_MANAGER(manager));
251 	REQUIRE(task != NULL);
252 	REQUIRE(action != NULL);
253 
254 	isc_timer_t *timer;
255 	isc_result_t result;
256 	isc_time_t now;
257 
258 	/*
259 	 * Create a new 'type' timer managed by 'manager'.  The timers
260 	 * parameters are specified by 'expires' and 'interval'.  Events
261 	 * will be posted to 'task' and when dispatched 'action' will be
262 	 * called with 'arg' as the arg value.  The new timer is returned
263 	 * in 'timerp'.
264 	 */
265 	if (expires == NULL) {
266 		expires = isc_time_epoch;
267 	}
268 	if (interval == NULL) {
269 		interval = isc_interval_zero;
270 	}
271 	REQUIRE(type == isc_timertype_inactive ||
272 		!(isc_time_isepoch(expires) && isc_interval_iszero(interval)));
273 	REQUIRE(timerp != NULL && *timerp == NULL);
274 	REQUIRE(type != isc_timertype_limited ||
275 		!(isc_time_isepoch(expires) || isc_interval_iszero(interval)));
276 
277 	/*
278 	 * Get current time.
279 	 */
280 	if (type != isc_timertype_inactive) {
281 		TIME_NOW(&now);
282 	} else {
283 		/*
284 		 * We don't have to do this, but it keeps the compiler from
285 		 * complaining about "now" possibly being used without being
286 		 * set, even though it will never actually happen.
287 		 */
288 		isc_time_settoepoch(&now);
289 	}
290 
291 	timer = isc_mem_get(manager->mctx, sizeof(*timer));
292 
293 	timer->manager = manager;
294 
295 	if (type == isc_timertype_once && !isc_interval_iszero(interval)) {
296 		result = isc_time_add(&now, interval, &timer->idle);
297 		if (result != ISC_R_SUCCESS) {
298 			isc_mem_put(manager->mctx, timer, sizeof(*timer));
299 			return (result);
300 		}
301 	} else {
302 		isc_time_settoepoch(&timer->idle);
303 	}
304 
305 	timer->type = type;
306 	timer->expires = *expires;
307 	timer->interval = *interval;
308 	timer->task = NULL;
309 	isc_task_attach(task, &timer->task);
310 	timer->action = action;
311 	/*
312 	 * Removing the const attribute from "arg" is the best of two
313 	 * evils here.  If the timer->arg member is made const, then
314 	 * it affects a great many recipients of the timer event
315 	 * which did not pass in an "arg" that was truly const.
316 	 * Changing isc_timer_create() to not have "arg" prototyped as const,
317 	 * though, can cause compilers warnings for calls that *do*
318 	 * have a truly const arg.  The caller will have to carefully
319 	 * keep track of whether arg started as a true const.
320 	 */
321 	DE_CONST(arg, timer->arg);
322 	timer->index = 0;
323 	isc_mutex_init(&timer->lock);
324 	ISC_LINK_INIT(timer, link);
325 
326 	ISC_LIST_INIT(timer->active);
327 
328 	timer->magic = TIMER_MAGIC;
329 
330 	LOCK(&manager->lock);
331 
332 	/*
333 	 * Note we don't have to lock the timer like we normally would because
334 	 * there are no external references to it yet.
335 	 */
336 
337 	if (type != isc_timertype_inactive) {
338 		result = schedule(timer, &now, true);
339 	} else {
340 		result = ISC_R_SUCCESS;
341 	}
342 	if (result == ISC_R_SUCCESS) {
343 		*timerp = timer;
344 		APPEND(manager->timers, timer, link);
345 	}
346 
347 	UNLOCK(&manager->lock);
348 
349 	if (result != ISC_R_SUCCESS) {
350 		timer->magic = 0;
351 		isc_mutex_destroy(&timer->lock);
352 		isc_task_detach(&timer->task);
353 		isc_mem_put(manager->mctx, timer, sizeof(*timer));
354 		return (result);
355 	}
356 
357 	return (ISC_R_SUCCESS);
358 }
359 
360 isc_result_t
isc_timer_reset(isc_timer_t * timer,isc_timertype_t type,const isc_time_t * expires,const isc_interval_t * interval,bool purge)361 isc_timer_reset(isc_timer_t *timer, isc_timertype_t type,
362 		const isc_time_t *expires, const isc_interval_t *interval,
363 		bool purge) {
364 	isc_time_t now;
365 	isc_timermgr_t *manager;
366 	isc_result_t result;
367 
368 	/*
369 	 * Change the timer's type, expires, and interval values to the given
370 	 * values.  If 'purge' is true, any pending events from this timer
371 	 * are purged from its task's event queue.
372 	 */
373 
374 	REQUIRE(VALID_TIMER(timer));
375 	manager = timer->manager;
376 	REQUIRE(VALID_MANAGER(manager));
377 
378 	if (expires == NULL) {
379 		expires = isc_time_epoch;
380 	}
381 	if (interval == NULL) {
382 		interval = isc_interval_zero;
383 	}
384 	REQUIRE(type == isc_timertype_inactive ||
385 		!(isc_time_isepoch(expires) && isc_interval_iszero(interval)));
386 	REQUIRE(type != isc_timertype_limited ||
387 		!(isc_time_isepoch(expires) || isc_interval_iszero(interval)));
388 
389 	/*
390 	 * Get current time.
391 	 */
392 	if (type != isc_timertype_inactive) {
393 		TIME_NOW(&now);
394 	} else {
395 		/*
396 		 * We don't have to do this, but it keeps the compiler from
397 		 * complaining about "now" possibly being used without being
398 		 * set, even though it will never actually happen.
399 		 */
400 		isc_time_settoepoch(&now);
401 	}
402 
403 	LOCK(&manager->lock);
404 	LOCK(&timer->lock);
405 
406 	if (purge) {
407 		timer_purge(timer);
408 	}
409 	timer->type = type;
410 	timer->expires = *expires;
411 	timer->interval = *interval;
412 	if (type == isc_timertype_once && !isc_interval_iszero(interval)) {
413 		result = isc_time_add(&now, interval, &timer->idle);
414 	} else {
415 		isc_time_settoepoch(&timer->idle);
416 		result = ISC_R_SUCCESS;
417 	}
418 
419 	if (result == ISC_R_SUCCESS) {
420 		if (type == isc_timertype_inactive) {
421 			deschedule(timer);
422 			result = ISC_R_SUCCESS;
423 		} else {
424 			result = schedule(timer, &now, true);
425 		}
426 	}
427 
428 	UNLOCK(&timer->lock);
429 	UNLOCK(&manager->lock);
430 
431 	return (result);
432 }
433 
434 isc_timertype_t
isc_timer_gettype(isc_timer_t * timer)435 isc_timer_gettype(isc_timer_t *timer) {
436 	isc_timertype_t t;
437 
438 	REQUIRE(VALID_TIMER(timer));
439 
440 	LOCK(&timer->lock);
441 	t = timer->type;
442 	UNLOCK(&timer->lock);
443 
444 	return (t);
445 }
446 
447 isc_result_t
isc_timer_touch(isc_timer_t * timer)448 isc_timer_touch(isc_timer_t *timer) {
449 	isc_result_t result;
450 	isc_time_t now;
451 
452 	/*
453 	 * Set the last-touched time of 'timer' to the current time.
454 	 */
455 
456 	REQUIRE(VALID_TIMER(timer));
457 
458 	LOCK(&timer->lock);
459 
460 	/*
461 	 * We'd like to
462 	 *
463 	 *	REQUIRE(timer->type == isc_timertype_once);
464 	 *
465 	 * but we cannot without locking the manager lock too, which we
466 	 * don't want to do.
467 	 */
468 
469 	TIME_NOW(&now);
470 	result = isc_time_add(&now, &timer->interval, &timer->idle);
471 
472 	UNLOCK(&timer->lock);
473 
474 	return (result);
475 }
476 
477 void
isc_timer_destroy(isc_timer_t ** timerp)478 isc_timer_destroy(isc_timer_t **timerp) {
479 	isc_timer_t *timer = NULL;
480 	isc_timermgr_t *manager = NULL;
481 
482 	REQUIRE(timerp != NULL && VALID_TIMER(*timerp));
483 
484 	timer = *timerp;
485 	*timerp = NULL;
486 
487 	manager = timer->manager;
488 
489 	LOCK(&manager->lock);
490 
491 	LOCK(&timer->lock);
492 	timer_purge(timer);
493 	deschedule(timer);
494 	UNLOCK(&timer->lock);
495 
496 	UNLINK(manager->timers, timer, link);
497 
498 	UNLOCK(&manager->lock);
499 
500 	isc_task_detach(&timer->task);
501 	isc_mutex_destroy(&timer->lock);
502 	timer->magic = 0;
503 	isc_mem_put(manager->mctx, timer, sizeof(*timer));
504 }
505 
506 static void
timer_post_event(isc_timermgr_t * manager,isc_timer_t * timer,isc_eventtype_t type)507 timer_post_event(isc_timermgr_t *manager, isc_timer_t *timer,
508 		 isc_eventtype_t type) {
509 	isc_timerevent_t *event;
510 	XTRACEID("posting", timer);
511 
512 	event = (isc_timerevent_t *)isc_event_allocate(
513 		manager->mctx, timer, type, timer->action, timer->arg,
514 		sizeof(*event));
515 
516 	ISC_LINK_INIT(event, ev_timerlink);
517 	((isc_event_t *)event)->ev_destroy = timerevent_destroy;
518 	((isc_event_t *)event)->ev_destroy_arg = timer;
519 
520 	event->due = timer->due;
521 
522 	LOCK(&timer->lock);
523 	ISC_LIST_APPEND(timer->active, event, ev_timerlink);
524 	UNLOCK(&timer->lock);
525 
526 	isc_task_send(timer->task, ISC_EVENT_PTR(&event));
527 }
528 
529 static void
dispatch(isc_timermgr_t * manager,isc_time_t * now)530 dispatch(isc_timermgr_t *manager, isc_time_t *now) {
531 	bool done = false, post_event, need_schedule;
532 	isc_eventtype_t type = 0;
533 	isc_timer_t *timer;
534 	isc_result_t result;
535 	bool idle;
536 
537 	/*!
538 	 * The caller must be holding the manager lock.
539 	 */
540 
541 	while (manager->nscheduled > 0 && !done) {
542 		timer = isc_heap_element(manager->heap, 1);
543 		INSIST(timer != NULL && timer->type != isc_timertype_inactive);
544 		if (isc_time_compare(now, &timer->due) >= 0) {
545 			if (timer->type == isc_timertype_ticker) {
546 				type = ISC_TIMEREVENT_TICK;
547 				post_event = true;
548 				need_schedule = true;
549 			} else if (timer->type == isc_timertype_limited) {
550 				int cmp;
551 				cmp = isc_time_compare(now, &timer->expires);
552 				if (cmp >= 0) {
553 					type = ISC_TIMEREVENT_LIFE;
554 					post_event = true;
555 					need_schedule = false;
556 				} else {
557 					type = ISC_TIMEREVENT_TICK;
558 					post_event = true;
559 					need_schedule = true;
560 				}
561 			} else if (!isc_time_isepoch(&timer->expires) &&
562 				   isc_time_compare(now, &timer->expires) >= 0)
563 			{
564 				type = ISC_TIMEREVENT_LIFE;
565 				post_event = true;
566 				need_schedule = false;
567 			} else {
568 				idle = false;
569 
570 				LOCK(&timer->lock);
571 				if (!isc_time_isepoch(&timer->idle) &&
572 				    isc_time_compare(now, &timer->idle) >= 0)
573 				{
574 					idle = true;
575 				}
576 				UNLOCK(&timer->lock);
577 				if (idle) {
578 					type = ISC_TIMEREVENT_IDLE;
579 					post_event = true;
580 					need_schedule = false;
581 				} else {
582 					/*
583 					 * Idle timer has been touched;
584 					 * reschedule.
585 					 */
586 					XTRACEID("idle reschedule", timer);
587 					post_event = false;
588 					need_schedule = true;
589 				}
590 			}
591 
592 			if (post_event) {
593 				timer_post_event(manager, timer, type);
594 			}
595 
596 			timer->index = 0;
597 			isc_heap_delete(manager->heap, 1);
598 			manager->nscheduled--;
599 
600 			if (need_schedule) {
601 				result = schedule(timer, now, false);
602 				if (result != ISC_R_SUCCESS) {
603 					UNEXPECTED_ERROR(__FILE__, __LINE__,
604 							 "%s: %u",
605 							 "couldn't schedule "
606 							 "timer",
607 							 result);
608 				}
609 			}
610 		} else {
611 			manager->due = timer->due;
612 			done = true;
613 		}
614 	}
615 }
616 
617 static isc_threadresult_t
618 #ifdef _WIN32 /* XXXDCL */
619 	WINAPI
620 #endif /* ifdef _WIN32 */
run(void * uap)621 	run(void *uap) {
622 	isc_timermgr_t *manager = uap;
623 	isc_time_t now;
624 	isc_result_t result;
625 
626 	LOCK(&manager->lock);
627 	while (!manager->done) {
628 		TIME_NOW(&now);
629 
630 		XTRACETIME("running", now);
631 
632 		dispatch(manager, &now);
633 
634 		if (manager->nscheduled > 0) {
635 			XTRACETIME2("waituntil", manager->due, now);
636 			result = WAITUNTIL(&manager->wakeup, &manager->lock,
637 					   &manager->due);
638 			INSIST(result == ISC_R_SUCCESS ||
639 			       result == ISC_R_TIMEDOUT);
640 		} else {
641 			XTRACETIME("wait", now);
642 			WAIT(&manager->wakeup, &manager->lock);
643 		}
644 		XTRACE("wakeup");
645 	}
646 	UNLOCK(&manager->lock);
647 
648 #ifdef OPENSSL_LEAKS
649 	ERR_remove_state(0);
650 #endif /* ifdef OPENSSL_LEAKS */
651 
652 	return ((isc_threadresult_t)0);
653 }
654 
655 static bool
sooner(void * v1,void * v2)656 sooner(void *v1, void *v2) {
657 	isc_timer_t *t1, *t2;
658 
659 	t1 = v1;
660 	t2 = v2;
661 	REQUIRE(VALID_TIMER(t1));
662 	REQUIRE(VALID_TIMER(t2));
663 
664 	if (isc_time_compare(&t1->due, &t2->due) < 0) {
665 		return (true);
666 	}
667 	return (false);
668 }
669 
670 static void
set_index(void * what,unsigned int index)671 set_index(void *what, unsigned int index) {
672 	isc_timer_t *timer;
673 
674 	REQUIRE(VALID_TIMER(what));
675 	timer = what;
676 
677 	timer->index = index;
678 }
679 
680 isc_result_t
isc_timermgr_create(isc_mem_t * mctx,isc_timermgr_t ** managerp)681 isc_timermgr_create(isc_mem_t *mctx, isc_timermgr_t **managerp) {
682 	isc_timermgr_t *manager;
683 
684 	/*
685 	 * Create a timer manager.
686 	 */
687 
688 	REQUIRE(managerp != NULL && *managerp == NULL);
689 
690 	manager = isc_mem_get(mctx, sizeof(*manager));
691 
692 	manager->magic = TIMER_MANAGER_MAGIC;
693 	manager->mctx = NULL;
694 	manager->done = false;
695 	INIT_LIST(manager->timers);
696 	manager->nscheduled = 0;
697 	isc_time_settoepoch(&manager->due);
698 	manager->heap = NULL;
699 	isc_heap_create(mctx, sooner, set_index, 0, &manager->heap);
700 	isc_mutex_init(&manager->lock);
701 	isc_mem_attach(mctx, &manager->mctx);
702 	isc_condition_init(&manager->wakeup);
703 	isc_thread_create(run, manager, &manager->thread);
704 	isc_thread_setname(manager->thread, "timer");
705 
706 	*managerp = manager;
707 
708 	return (ISC_R_SUCCESS);
709 }
710 
711 void
isc_timermgr_poke(isc_timermgr_t * manager)712 isc_timermgr_poke(isc_timermgr_t *manager) {
713 	REQUIRE(VALID_MANAGER(manager));
714 
715 	SIGNAL(&manager->wakeup);
716 }
717 
718 void
isc_timermgr_destroy(isc_timermgr_t ** managerp)719 isc_timermgr_destroy(isc_timermgr_t **managerp) {
720 	isc_timermgr_t *manager;
721 
722 	/*
723 	 * Destroy a timer manager.
724 	 */
725 
726 	REQUIRE(managerp != NULL);
727 	manager = *managerp;
728 	REQUIRE(VALID_MANAGER(manager));
729 
730 	LOCK(&manager->lock);
731 
732 	REQUIRE(EMPTY(manager->timers));
733 	manager->done = true;
734 
735 	XTRACE("signal (destroy)");
736 	SIGNAL(&manager->wakeup);
737 
738 	UNLOCK(&manager->lock);
739 
740 	/*
741 	 * Wait for thread to exit.
742 	 */
743 	isc_thread_join(manager->thread, NULL);
744 
745 	/*
746 	 * Clean up.
747 	 */
748 	(void)isc_condition_destroy(&manager->wakeup);
749 	isc_mutex_destroy(&manager->lock);
750 	isc_heap_destroy(&manager->heap);
751 	manager->magic = 0;
752 	isc_mem_putanddetach(&manager->mctx, manager, sizeof(*manager));
753 
754 	*managerp = NULL;
755 }
756