ISC BIND version 9.2.2rc1

1 files changed, 864 insertions, 0 deletions

diff --git a/usr.sbin/bind/lib/isc/timer.c b/usr.sbin/bind/lib/isc/timer.c
new file mode 100644
index 00000000000..d3cdfc4ba78
--- /dev/null
+++ b/usr.sbin/bind/lib/isc/timer.c
@@ -0,0 +1,864 @@
+/*
+ * Copyright (C) 1998-2001  Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
+ * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
+ * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
+ * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $ISC: timer.c,v 1.64 2001/06/04 19:33:29 tale Exp $ */
+
+#include <config.h>
+
+#include <isc/condition.h>
+#include <isc/heap.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/msgs.h>
+#include <isc/platform.h>
+#include <isc/task.h>
+#include <isc/thread.h>
+#include <isc/time.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#ifndef ISC_PLATFORM_USETHREADS
+#include "timer_p.h"
+#endif /* ISC_PLATFORM_USETHREADS */
+
+#ifdef ISC_TIMER_TRACE
+#define XTRACE(s)			printf("%s\n", (s))
+#define XTRACEID(s, t)			printf("%s %p\n", (s), (t))
+#define XTRACETIME(s, d)		printf("%s %u.%09u\n", (s), \
+					       (d).seconds, (d).nanoseconds)
+#define XTRACETIMER(s, t, d)		printf("%s %p %u.%09u\n", (s), (t), \
+					       (d).seconds, (d).nanoseconds)
+#else
+#define XTRACE(s)
+#define XTRACEID(s, t)
+#define XTRACETIME(s, d)
+#define XTRACETIMER(s, t, d)
+#endif /* ISC_TIMER_TRACE */
+
+#define TIMER_MAGIC			ISC_MAGIC('T', 'I', 'M', 'R')
+#define VALID_TIMER(t)			ISC_MAGIC_VALID(t, TIMER_MAGIC)
+
+struct isc_timer {
+	/* Not locked. */
+	unsigned int			magic;
+	isc_timermgr_t *		manager;
+	isc_mutex_t			lock;
+	/* Locked by timer lock. */
+	unsigned int			references;
+	isc_time_t			idle;
+	/* Locked by manager lock. */
+	isc_timertype_t			type;
+	isc_time_t			expires;
+	isc_interval_t			interval;
+	isc_task_t *			task;
+	isc_taskaction_t		action;
+	void *				arg;
+	unsigned int			index;
+	isc_time_t			due;
+	LINK(isc_timer_t)		link;
+};
+
+#define TIMER_MANAGER_MAGIC		ISC_MAGIC('T', 'I', 'M', 'M')
+#define VALID_MANAGER(m)		ISC_MAGIC_VALID(m, TIMER_MANAGER_MAGIC)
+
+struct isc_timermgr {
+	/* Not locked. */
+	unsigned int			magic;
+	isc_mem_t *			mctx;
+	isc_mutex_t			lock;
+	/* Locked by manager lock. */
+	isc_boolean_t			done;
+	LIST(isc_timer_t)		timers;
+	unsigned int			nscheduled;
+	isc_time_t			due;
+#ifdef ISC_PLATFORM_USETHREADS
+	isc_condition_t			wakeup;
+	isc_thread_t			thread;
+#else /* ISC_PLATFORM_USETHREADS */
+	unsigned int			refs;
+#endif /* ISC_PLATFORM_USETHREADS */
+	isc_heap_t *			heap;
+};
+
+#ifndef ISC_PLATFORM_USETHREADS
+/*
+ * If threads are not in use, there can be only one.
+ */
+static isc_timermgr_t *timermgr = NULL;
+#endif /* ISC_PLATFORM_USETHREADS */
+
+static inline isc_result_t
+schedule(isc_timer_t *timer, isc_time_t *now, isc_boolean_t signal_ok) {
+	isc_result_t result;
+	isc_timermgr_t *manager;
+	isc_time_t due;
+	int cmp;
+
+	/*
+	 * Note: the caller must ensure locking.
+	 */
+
+	REQUIRE(timer->type != isc_timertype_inactive);
+
+#ifndef ISC_PLATFORM_USETHREADS
+	UNUSED(signal_ok);
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	/*
+	 * Compute the new due time.
+	 */
+	if (timer->type == isc_timertype_ticker) {
+		result = isc_time_add(now, &timer->interval, &due);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+	} else {
+		if (isc_time_isepoch(&timer->idle))
+			due = timer->expires;
+		else if (isc_time_isepoch(&timer->expires))
+			due = timer->idle;
+		else if (isc_time_compare(&timer->idle, &timer->expires) < 0)
+			due = timer->idle;
+		else
+			due = timer->expires;
+	}
+
+	/*
+	 * Schedule the timer.
+	 */
+	manager = timer->manager;
+	if (timer->index > 0) {
+		/*
+		 * Already scheduled.
+		 */
+		cmp = isc_time_compare(&due, &timer->due);
+		timer->due = due;
+		switch (cmp) {
+		case -1:
+			isc_heap_increased(manager->heap, timer->index);
+			break;
+		case 1:
+			isc_heap_decreased(manager->heap, timer->index);
+			break;
+		case 0:
+			/* Nothing to do. */
+			break;
+		}
+	} else {
+		timer->due = due;
+		result = isc_heap_insert(manager->heap, timer);
+		if (result != ISC_R_SUCCESS) {
+			INSIST(result == ISC_R_NOMEMORY);
+			return (ISC_R_NOMEMORY);
+		}
+		manager->nscheduled++;
+	}
+
+	XTRACETIMER(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TIMER,
+				   ISC_MSG_SCHEDULE, "schedule"), timer, due);
+
+	/*
+	 * If this timer is at the head of the queue, we need to ensure
+	 * that we won't miss it if it has a more recent due time than
+	 * the current "next" timer.  We do this either by waking up the
+	 * run thread, or explicitly setting the value in the manager.
+	 */
+#ifdef ISC_PLATFORM_USETHREADS
+	if (timer->index == 1 && signal_ok) {
+		XTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TIMER,
+				      ISC_MSG_SIGNALSCHED,
+				      "signal (schedule)"));
+		SIGNAL(&manager->wakeup);
+	}
+#else /* ISC_PLATFORM_USETHREADS */
+	if (timer->index == 1 &&
+	    isc_time_compare(&timer->due, &manager->due) < 0)
+		manager->due = timer->due;
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	return (ISC_R_SUCCESS);
+}
+
+static inline void
+deschedule(isc_timer_t *timer) {
+	isc_boolean_t need_wakeup = ISC_FALSE;
+	isc_timermgr_t *manager;
+
+	/*
+	 * The caller must ensure locking.
+	 */
+
+	manager = timer->manager;
+	if (timer->index > 0) {
+		if (timer->index == 1)
+			need_wakeup = ISC_TRUE;
+		isc_heap_delete(manager->heap, timer->index);
+		timer->index = 0;
+		INSIST(manager->nscheduled > 0);
+		manager->nscheduled--;
+#ifdef ISC_PLATFORM_USETHREADS
+		if (need_wakeup) {
+			XTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TIMER,
+					      ISC_MSG_SIGNALDESCHED,
+					      "signal (deschedule)"));
+			SIGNAL(&manager->wakeup);
+		}
+#endif /* ISC_PLATFORM_USETHREADS */
+	}
+}
+
+static void
+destroy(isc_timer_t *timer) {
+	isc_timermgr_t *manager = timer->manager;
+
+	/*
+	 * The caller must ensure it is safe to destroy the timer.
+	 */
+
+	LOCK(&manager->lock);
+
+	isc_task_purgerange(timer->task,
+			    timer,
+			    ISC_TIMEREVENT_FIRSTEVENT,
+			    ISC_TIMEREVENT_LASTEVENT,
+			    NULL);
+	deschedule(timer);
+	UNLINK(manager->timers, timer, link);
+
+	UNLOCK(&manager->lock);
+
+	isc_task_detach(&timer->task);
+	DESTROYLOCK(&timer->lock);
+	timer->magic = 0;
+	isc_mem_put(manager->mctx, timer, sizeof *timer);
+}
+
+isc_result_t
+isc_timer_create(isc_timermgr_t *manager, isc_timertype_t type,
+		 isc_time_t *expires, isc_interval_t *interval,
+		 isc_task_t *task, isc_taskaction_t action, const void *arg,
+		 isc_timer_t **timerp)
+{
+	isc_timer_t *timer;
+	isc_result_t result;
+	isc_time_t now;
+
+	/*
+	 * Create a new 'type' timer managed by 'manager'.  The timers
+	 * parameters are specified by 'expires' and 'interval'.  Events
+	 * will be posted to 'task' and when dispatched 'action' will be
+	 * called with 'arg' as the arg value.  The new timer is returned
+	 * in 'timerp'.
+	 */
+
+	REQUIRE(VALID_MANAGER(manager));
+	REQUIRE(task != NULL);
+	REQUIRE(action != NULL);
+	if (expires == NULL)
+		expires = isc_time_epoch;
+	if (interval == NULL)
+		interval = isc_interval_zero;
+	REQUIRE(type == isc_timertype_inactive ||
+		!(isc_time_isepoch(expires) && isc_interval_iszero(interval)));
+	REQUIRE(timerp != NULL && *timerp == NULL);
+
+	/*
+	 * Get current time.
+	 */
+	if (type != isc_timertype_inactive) {
+		result = isc_time_now(&now);
+		if (result != ISC_R_SUCCESS) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__,
+					 "isc_time_now() %s: %s",
+					 isc_msgcat_get(isc_msgcat,
+							ISC_MSGSET_GENERAL,
+							ISC_MSG_FAILED,
+							"failed"),
+					 isc_result_totext(result));
+			return (ISC_R_UNEXPECTED);
+		}
+	} else {
+		/*
+		 * We don't have to do this, but it keeps the compiler from
+		 * complaining about "now" possibly being used without being
+		 * set, even though it will never actually happen.
+		 */
+		isc_time_settoepoch(&now);
+	}
+
+
+	timer = isc_mem_get(manager->mctx, sizeof *timer);
+	if (timer == NULL)
+		return (ISC_R_NOMEMORY);
+
+	timer->manager = manager;
+	timer->references = 1;
+
+	if (type == isc_timertype_once && !isc_interval_iszero(interval)) {
+		result = isc_time_add(&now, interval, &timer->idle);
+		if (result != ISC_R_SUCCESS)
+			return (result);
+	} else
+		isc_time_settoepoch(&timer->idle);
+
+	timer->type = type;
+	timer->expires = *expires;
+	timer->interval = *interval;
+	timer->task = NULL;
+	isc_task_attach(task, &timer->task);
+	timer->action = action;
+	/*
+	 * Removing the const attribute from "arg" is the best of two
+	 * evils here.  If the timer->arg member is made const, then
+	 * it affects a great many recipients of the timer event
+	 * which did not pass in an "arg" that was truly const.
+	 * Changing isc_timer_create() to not have "arg" prototyped as const,
+	 * though, can cause compilers warnings for calls that *do*
+	 * have a truly const arg.  The caller will have to carefully
+	 * keep track of whether arg started as a true const.
+	 */
+	DE_CONST(arg, timer->arg);
+	timer->index = 0;
+	if (isc_mutex_init(&timer->lock) != ISC_R_SUCCESS) {
+		isc_task_detach(&timer->task);
+		isc_mem_put(manager->mctx, timer, sizeof *timer);
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_mutex_init() %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"));
+		return (ISC_R_UNEXPECTED);
+	}
+	ISC_LINK_INIT(timer, link);
+	timer->magic = TIMER_MAGIC;
+
+	LOCK(&manager->lock);
+
+	/*
+	 * Note we don't have to lock the timer like we normally would because
+	 * there are no external references to it yet.
+	 */
+
+	if (type != isc_timertype_inactive)
+		result = schedule(timer, &now, ISC_TRUE);
+	else
+		result = ISC_R_SUCCESS;
+	if (result == ISC_R_SUCCESS)
+		APPEND(manager->timers, timer, link);
+
+	UNLOCK(&manager->lock);
+
+	if (result != ISC_R_SUCCESS) {
+		timer->magic = 0;
+		DESTROYLOCK(&timer->lock);
+		isc_task_detach(&timer->task);
+		isc_mem_put(manager->mctx, timer, sizeof *timer);
+		return (result);
+	}
+
+	*timerp = timer;
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_timer_reset(isc_timer_t *timer, isc_timertype_t type,
+		isc_time_t *expires, isc_interval_t *interval,
+		isc_boolean_t purge)
+{
+	isc_time_t now;
+	isc_timermgr_t *manager;
+	isc_result_t result;
+
+	/*
+	 * Change the timer's type, expires, and interval values to the given
+	 * values.  If 'purge' is ISC_TRUE, any pending events from this timer
+	 * are purged from its task's event queue.
+	 */
+
+	REQUIRE(VALID_TIMER(timer));
+	manager = timer->manager;
+	REQUIRE(VALID_MANAGER(manager));
+	if (expires == NULL)
+		expires = isc_time_epoch;
+	if (interval == NULL)
+		interval = isc_interval_zero;
+	REQUIRE(type == isc_timertype_inactive ||
+		!(isc_time_isepoch(expires) && isc_interval_iszero(interval)));
+
+	/*
+	 * Get current time.
+	 */
+	if (type != isc_timertype_inactive) {
+		result = isc_time_now(&now);
+		if (result != ISC_R_SUCCESS) {
+			UNEXPECTED_ERROR(__FILE__, __LINE__,
+					 "isc_time_now() %s: %s",
+					 isc_msgcat_get(isc_msgcat,
+							ISC_MSGSET_GENERAL,
+							ISC_MSG_FAILED,
+							"failed"),
+					 isc_result_totext(result));
+			return (ISC_R_UNEXPECTED);
+		}
+	} else {
+		/*
+		 * We don't have to do this, but it keeps the compiler from
+		 * complaining about "now" possibly being used without being
+		 * set, even though it will never actually happen.
+		 */
+		isc_time_settoepoch(&now);
+	}
+
+	manager = timer->manager;
+
+	LOCK(&manager->lock);
+	LOCK(&timer->lock);
+
+	if (purge)
+		isc_task_purgerange(timer->task,
+				    timer,
+				    ISC_TIMEREVENT_FIRSTEVENT,
+				    ISC_TIMEREVENT_LASTEVENT,
+				    NULL);
+	timer->type = type;
+	timer->expires = *expires;
+	timer->interval = *interval;
+	if (type == isc_timertype_once && !isc_interval_iszero(interval)) {
+		result = isc_time_add(&now, interval, &timer->idle);
+	} else {
+		isc_time_settoepoch(&timer->idle);
+		result = ISC_R_SUCCESS;
+	}
+
+	if (result == ISC_R_SUCCESS) {
+		if (type == isc_timertype_inactive) {
+			deschedule(timer);
+			result = ISC_R_SUCCESS;
+		} else
+			result = schedule(timer, &now, ISC_TRUE);
+	}
+
+	UNLOCK(&timer->lock);
+	UNLOCK(&manager->lock);
+
+	return (result);
+}
+
+isc_result_t
+isc_timer_touch(isc_timer_t *timer) {
+	isc_result_t result;
+	isc_time_t now;
+
+	/*
+	 * Set the last-touched time of 'timer' to the current time.
+	 */
+
+	REQUIRE(VALID_TIMER(timer));
+
+	LOCK(&timer->lock);
+
+	/*
+	 * We'd like to
+	 *
+	 *	REQUIRE(timer->type == isc_timertype_once);
+	 *
+	 * but we cannot without locking the manager lock too, which we
+	 * don't want to do.
+	 */
+
+	result = isc_time_now(&now);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_time_now() %s: %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"),
+				 isc_result_totext(result));
+		result = ISC_R_UNEXPECTED;
+	} else
+		result = isc_time_add(&now, &timer->interval, &timer->idle);
+
+	UNLOCK(&timer->lock);
+
+	return (result);
+}
+
+void
+isc_timer_attach(isc_timer_t *timer, isc_timer_t **timerp) {
+	/*
+	 * Attach *timerp to timer.
+	 */
+
+	REQUIRE(VALID_TIMER(timer));
+	REQUIRE(timerp != NULL && *timerp == NULL);
+
+	LOCK(&timer->lock);
+	timer->references++;
+	UNLOCK(&timer->lock);
+
+	*timerp = timer;
+}
+
+void
+isc_timer_detach(isc_timer_t **timerp) {
+	isc_timer_t *timer;
+	isc_boolean_t free_timer = ISC_FALSE;
+
+	/*
+	 * Detach *timerp from its timer.
+	 */
+
+	REQUIRE(timerp != NULL);
+	timer = *timerp;
+	REQUIRE(VALID_TIMER(timer));
+
+	LOCK(&timer->lock);
+	REQUIRE(timer->references > 0);
+	timer->references--;
+	if (timer->references == 0)
+		free_timer = ISC_TRUE;
+	UNLOCK(&timer->lock);
+
+	if (free_timer)
+		destroy(timer);
+
+	*timerp = NULL;
+}
+
+static void
+dispatch(isc_timermgr_t *manager, isc_time_t *now) {
+	isc_boolean_t done = ISC_FALSE, post_event, need_schedule;
+	isc_event_t *event;
+	isc_eventtype_t type = 0;
+	isc_timer_t *timer;
+	isc_result_t result;
+
+	/*
+	 * The caller must be holding the manager lock.
+	 */
+
+	while (manager->nscheduled > 0 && !done) {
+		timer = isc_heap_element(manager->heap, 1);
+		INSIST(timer->type != isc_timertype_inactive);
+		if (isc_time_compare(now, &timer->due) >= 0) {
+			if (timer->type == isc_timertype_ticker) {
+				type = ISC_TIMEREVENT_TICK;
+				post_event = ISC_TRUE;
+				need_schedule = ISC_TRUE;
+			} else if (!isc_time_isepoch(&timer->expires) &&
+				   isc_time_compare(now,
+						    &timer->expires) >= 0) {
+				type = ISC_TIMEREVENT_LIFE;
+				post_event = ISC_TRUE;
+				need_schedule = ISC_FALSE;
+			} else if (!isc_time_isepoch(&timer->idle) &&
+				   isc_time_compare(now,
+						    &timer->idle) >= 0) {
+				type = ISC_TIMEREVENT_IDLE;
+				post_event = ISC_TRUE;
+				need_schedule = ISC_FALSE;
+			} else {
+				/*
+				 * Idle timer has been touched; reschedule.
+				 */
+				XTRACEID(isc_msgcat_get(isc_msgcat,
+							ISC_MSGSET_TIMER,
+							ISC_MSG_IDLERESCHED,
+							"idle reschedule"),
+					 timer);
+				post_event = ISC_FALSE;
+				need_schedule = ISC_TRUE;
+			}
+
+			if (post_event) {
+				XTRACEID(isc_msgcat_get(isc_msgcat,
+							ISC_MSGSET_TIMER,
+							ISC_MSG_POSTING,
+							"posting"), timer);
+				/*
+				 * XXX We could preallocate this event.
+				 */
+				event = isc_event_allocate(manager->mctx,
+							   timer,
+							   type,
+							   timer->action,
+							   timer->arg,
+							   sizeof *event);
+
+				if (event != NULL)
+					isc_task_send(timer->task, &event);
+				else
+					UNEXPECTED_ERROR(__FILE__, __LINE__,
+						 isc_msgcat_get(isc_msgcat,
+							 ISC_MSGSET_TIMER,
+							 ISC_MSG_EVENTNOTALLOC,
+							 "couldn't "
+							 "allocate event"));
+			}
+
+			timer->index = 0;
+			isc_heap_delete(manager->heap, 1);
+			manager->nscheduled--;
+
+			if (need_schedule) {
+				result = schedule(timer, now, ISC_FALSE);
+				if (result != ISC_R_SUCCESS)
+					UNEXPECTED_ERROR(__FILE__, __LINE__,
+						isc_msgcat_get(isc_msgcat,
+							ISC_MSGSET_TIMER,
+							ISC_MSG_SCHEDFAIL,
+							"couldn't "
+							"schedule timer: %u"),
+							 result);
+			}
+		} else {
+			manager->due = timer->due;
+			done = ISC_TRUE;
+		}
+	}
+}
+
+#ifdef ISC_PLATFORM_USETHREADS
+static isc_threadresult_t
+#ifdef _WIN32			/* XXXDCL */
+WINAPI
+#endif
+run(void *uap) {
+	isc_timermgr_t *manager = uap;
+	isc_time_t now;
+	isc_result_t result;
+
+	LOCK(&manager->lock);
+	while (!manager->done) {
+		RUNTIME_CHECK(isc_time_now(&now) == ISC_R_SUCCESS);
+
+		XTRACETIME(isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+					  ISC_MSG_RUNNING,
+					  "running"), now);
+
+		dispatch(manager, &now);
+
+		if (manager->nscheduled > 0) {
+			XTRACETIME(isc_msgcat_get(isc_msgcat,
+						  ISC_MSGSET_GENERAL,
+						  ISC_MSG_WAITUNTIL,
+						  "waituntil"),
+				   manager->due);
+			result = WAITUNTIL(&manager->wakeup, &manager->lock,
+					   &manager->due);
+			INSIST(result == ISC_R_SUCCESS ||
+			       result == ISC_R_TIMEDOUT);
+		} else {
+			XTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+					      ISC_MSG_WAIT, "wait"));
+			WAIT(&manager->wakeup, &manager->lock);
+		}
+		XTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TIMER,
+				      ISC_MSG_WAKEUP, "wakeup"));
+	}
+	UNLOCK(&manager->lock);
+
+	return ((isc_threadresult_t)0);
+}
+#endif /* ISC_PLATFORM_USETHREADS */
+
+static isc_boolean_t
+sooner(void *v1, void *v2) {
+	isc_timer_t *t1, *t2;
+
+	t1 = v1;
+	t2 = v2;
+	REQUIRE(VALID_TIMER(t1));
+	REQUIRE(VALID_TIMER(t2));
+
+	if (isc_time_compare(&t1->due, &t2->due) < 0)
+		return (ISC_TRUE);
+	return (ISC_FALSE);
+}
+
+static void
+set_index(void *what, unsigned int index) {
+	isc_timer_t *timer;
+
+	timer = what;
+	REQUIRE(VALID_TIMER(timer));
+
+	timer->index = index;
+}
+
+isc_result_t
+isc_timermgr_create(isc_mem_t *mctx, isc_timermgr_t **managerp) {
+	isc_timermgr_t *manager;
+	isc_result_t result;
+
+	/*
+	 * Create a timer manager.
+	 */
+
+	REQUIRE(managerp != NULL && *managerp == NULL);
+
+#ifndef ISC_PLATFORM_USETHREADS
+	if (timermgr != NULL) {
+		timermgr->refs++;
+		*managerp = timermgr;
+		return (ISC_R_SUCCESS);
+	}
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	manager = isc_mem_get(mctx, sizeof *manager);
+	if (manager == NULL)
+		return (ISC_R_NOMEMORY);
+
+	manager->magic = TIMER_MANAGER_MAGIC;
+	manager->mctx = NULL;
+	manager->done = ISC_FALSE;
+	INIT_LIST(manager->timers);
+	manager->nscheduled = 0;
+	isc_time_settoepoch(&manager->due);
+	manager->heap = NULL;
+	result = isc_heap_create(mctx, sooner, set_index, 0, &manager->heap);
+	if (result != ISC_R_SUCCESS) {
+		INSIST(result == ISC_R_NOMEMORY);
+		isc_mem_put(mctx, manager, sizeof *manager);
+		return (ISC_R_NOMEMORY);
+	}
+	if (isc_mutex_init(&manager->lock) != ISC_R_SUCCESS) {
+		isc_heap_destroy(&manager->heap);
+		isc_mem_put(mctx, manager, sizeof *manager);
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_mutex_init() %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"));
+		return (ISC_R_UNEXPECTED);
+	}
+	isc_mem_attach(mctx, &manager->mctx);
+#ifdef ISC_PLATFORM_USETHREADS
+	if (isc_condition_init(&manager->wakeup) != ISC_R_SUCCESS) {
+		isc_mem_detach(&manager->mctx);
+		DESTROYLOCK(&manager->lock);
+		isc_heap_destroy(&manager->heap);
+		isc_mem_put(mctx, manager, sizeof *manager);
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_condition_init() %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"));
+		return (ISC_R_UNEXPECTED);
+	}
+	if (isc_thread_create(run, manager, &manager->thread) !=
+	    ISC_R_SUCCESS) {
+		isc_mem_detach(&manager->mctx);
+		(void)isc_condition_destroy(&manager->wakeup);
+		DESTROYLOCK(&manager->lock);
+		isc_heap_destroy(&manager->heap);
+		isc_mem_put(mctx, manager, sizeof *manager);
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_thread_create() %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"));
+		return (ISC_R_UNEXPECTED);
+	}
+#else /* ISC_PLATFORM_USETHREADS */
+	manager->refs = 1;
+	timermgr = manager;
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	*managerp = manager;
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc_timermgr_destroy(isc_timermgr_t **managerp) {
+	isc_timermgr_t *manager;
+	isc_mem_t *mctx;
+
+	/*
+	 * Destroy a timer manager.
+	 */
+
+	REQUIRE(managerp != NULL);
+	manager = *managerp;
+	REQUIRE(VALID_MANAGER(manager));
+
+	LOCK(&manager->lock);
+
+#ifndef ISC_PLATFORM_USETHREADS
+	if (manager->refs > 1) {
+		manager->refs--;
+		UNLOCK(&manager->lock);
+		*managerp = NULL;
+		return;
+	}
+
+	isc__timermgr_dispatch();
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	REQUIRE(EMPTY(manager->timers));
+	manager->done = ISC_TRUE;
+
+#ifdef ISC_PLATFORM_USETHREADS
+	XTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TIMER,
+			      ISC_MSG_SIGNALDESTROY, "signal (destroy)"));
+	SIGNAL(&manager->wakeup);
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	UNLOCK(&manager->lock);
+
+#ifdef ISC_PLATFORM_USETHREADS
+	/*
+	 * Wait for thread to exit.
+	 */
+	if (isc_thread_join(manager->thread, NULL) != ISC_R_SUCCESS)
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_thread_join() %s",
+				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
+						ISC_MSG_FAILED, "failed"));
+#endif /* ISC_PLATFORM_USETHREADS */
+
+	/*
+	 * Clean up.
+	 */
+#ifdef ISC_PLATFORM_USETHREADS
+	(void)isc_condition_destroy(&manager->wakeup);
+#endif /* ISC_PLATFORM_USETHREADS */
+	DESTROYLOCK(&manager->lock);
+	isc_heap_destroy(&manager->heap);
+	manager->magic = 0;
+	mctx = manager->mctx;
+	isc_mem_put(mctx, manager, sizeof *manager);
+	isc_mem_detach(&mctx);
+
+	*managerp = NULL;
+}
+
+#ifndef ISC_PLATFORM_USETHREADS
+isc_result_t
+isc__timermgr_nextevent(isc_time_t *when) {
+	if (timermgr == NULL || timermgr->nscheduled == 0)
+		return (ISC_R_NOTFOUND);
+	*when = timermgr->due;
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc__timermgr_dispatch(void) {
+	isc_time_t now;
+	if (timermgr == NULL)
+		return (ISC_R_NOTFOUND);
+	isc_time_now(&now);
+	dispatch(timermgr, &now);
+	return (ISC_R_SUCCESS);
+}
+#endif /* ISC_PLATFORM_USETHREADS */