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-rw-r--r--lib/isc/timer.c741
1 files changed, 741 insertions, 0 deletions
diff --git a/lib/isc/timer.c b/lib/isc/timer.c
new file mode 100644
index 0000000..40ae929
--- /dev/null
+++ b/lib/isc/timer.c
@@ -0,0 +1,741 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <stdbool.h>
+
+#include <isc/app.h>
+#include <isc/condition.h>
+#include <isc/heap.h>
+#include <isc/log.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/once.h>
+#include <isc/print.h>
+#include <isc/refcount.h>
+#include <isc/result.h>
+#include <isc/task.h>
+#include <isc/thread.h>
+#include <isc/time.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#include "timer_p.h"
+
+#ifdef ISC_TIMER_TRACE
+#define XTRACE(s) fprintf(stderr, "%s\n", (s))
+#define XTRACEID(s, t) fprintf(stderr, "%s %p\n", (s), (t))
+#define XTRACETIME(s, d) \
+ fprintf(stderr, "%s %u.%09u\n", (s), (d).seconds, (d).nanoseconds)
+#define XTRACETIME2(s, d, n) \
+ fprintf(stderr, "%s %u.%09u %u.%09u\n", (s), (d).seconds, \
+ (d).nanoseconds, (n).seconds, (n).nanoseconds)
+#define XTRACETIMER(s, t, d) \
+ fprintf(stderr, "%s %p %u.%09u\n", (s), (t), (d).seconds, \
+ (d).nanoseconds)
+#else /* ifdef ISC_TIMER_TRACE */
+#define XTRACE(s)
+#define XTRACEID(s, t)
+#define XTRACETIME(s, d)
+#define XTRACETIME2(s, d, n)
+#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. */
+ isc_time_t idle;
+ ISC_LIST(isc_timerevent_t) active;
+ /*! 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. */
+ bool done;
+ LIST(isc_timer_t) timers;
+ unsigned int nscheduled;
+ isc_time_t due;
+ isc_condition_t wakeup;
+ isc_thread_t thread;
+ isc_heap_t *heap;
+};
+
+void
+isc_timermgr_poke(isc_timermgr_t *manager);
+
+static inline isc_result_t
+schedule(isc_timer_t *timer, isc_time_t *now, bool signal_ok) {
+ isc_timermgr_t *manager;
+ isc_time_t due;
+
+ /*!
+ * Note: the caller must ensure locking.
+ */
+
+ REQUIRE(timer->type != isc_timertype_inactive);
+
+ manager = timer->manager;
+
+ /*
+ * Compute the new due time.
+ */
+ if (timer->type != isc_timertype_once) {
+ isc_result_t result = isc_time_add(now, &timer->interval, &due);
+ if (result != ISC_R_SUCCESS) {
+ return (result);
+ }
+ if (timer->type == isc_timertype_limited &&
+ isc_time_compare(&timer->expires, &due) < 0)
+ {
+ due = timer->expires;
+ }
+ } 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.
+ */
+
+ if (timer->index > 0) {
+ /*
+ * Already scheduled.
+ */
+ int 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;
+ isc_heap_insert(manager->heap, timer);
+ manager->nscheduled++;
+ }
+
+ XTRACETIMER("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.
+ */
+
+ if (timer->index == 1 && signal_ok) {
+ XTRACE("signal (schedule)");
+ SIGNAL(&manager->wakeup);
+ }
+
+ return (ISC_R_SUCCESS);
+}
+
+static inline void
+deschedule(isc_timer_t *timer) {
+ isc_timermgr_t *manager;
+
+ /*
+ * The caller must ensure locking.
+ */
+
+ manager = timer->manager;
+ if (timer->index > 0) {
+ bool need_wakeup = false;
+ if (timer->index == 1) {
+ need_wakeup = true;
+ }
+ isc_heap_delete(manager->heap, timer->index);
+ timer->index = 0;
+ INSIST(manager->nscheduled > 0);
+ manager->nscheduled--;
+ if (need_wakeup) {
+ XTRACE("signal (deschedule)");
+ SIGNAL(&manager->wakeup);
+ }
+ }
+}
+
+static void
+timerevent_unlink(isc_timer_t *timer, isc_timerevent_t *event) {
+ REQUIRE(ISC_LINK_LINKED(event, ev_timerlink));
+ ISC_LIST_UNLINK(timer->active, event, ev_timerlink);
+}
+
+static void
+timerevent_destroy(isc_event_t *event0) {
+ isc_timer_t *timer = event0->ev_destroy_arg;
+ isc_timerevent_t *event = (isc_timerevent_t *)event0;
+
+ LOCK(&timer->lock);
+ if (ISC_LINK_LINKED(event, ev_timerlink)) {
+ /* The event was unlinked via timer_purge() */
+ timerevent_unlink(timer, event);
+ }
+ UNLOCK(&timer->lock);
+
+ isc_mem_put(timer->manager->mctx, event, event0->ev_size);
+}
+
+static void
+timer_purge(isc_timer_t *timer) {
+ isc_timerevent_t *event = NULL;
+
+ while ((event = ISC_LIST_HEAD(timer->active)) != NULL) {
+ timerevent_unlink(timer, event);
+ UNLOCK(&timer->lock);
+ (void)isc_task_purgeevent(timer->task, (isc_event_t *)event);
+ LOCK(&timer->lock);
+ }
+}
+
+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) {
+ REQUIRE(VALID_MANAGER(manager));
+ REQUIRE(task != NULL);
+ REQUIRE(action != NULL);
+
+ 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'.
+ */
+ 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);
+ REQUIRE(type != isc_timertype_limited ||
+ !(isc_time_isepoch(expires) || isc_interval_iszero(interval)));
+
+ /*
+ * Get current time.
+ */
+ if (type != isc_timertype_inactive) {
+ TIME_NOW(&now);
+ } 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));
+
+ timer->manager = manager;
+
+ if (type == isc_timertype_once && !isc_interval_iszero(interval)) {
+ result = isc_time_add(&now, interval, &timer->idle);
+ if (result != ISC_R_SUCCESS) {
+ isc_mem_put(manager->mctx, timer, sizeof(*timer));
+ 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;
+ isc_mutex_init(&timer->lock);
+ ISC_LINK_INIT(timer, link);
+
+ ISC_LIST_INIT(timer->active);
+
+ 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, true);
+ } else {
+ result = ISC_R_SUCCESS;
+ }
+ if (result == ISC_R_SUCCESS) {
+ *timerp = timer;
+ APPEND(manager->timers, timer, link);
+ }
+
+ UNLOCK(&manager->lock);
+
+ if (result != ISC_R_SUCCESS) {
+ timer->magic = 0;
+ isc_mutex_destroy(&timer->lock);
+ isc_task_detach(&timer->task);
+ isc_mem_put(manager->mctx, timer, sizeof(*timer));
+ return (result);
+ }
+
+ return (ISC_R_SUCCESS);
+}
+
+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) {
+ 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 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)));
+ REQUIRE(type != isc_timertype_limited ||
+ !(isc_time_isepoch(expires) || isc_interval_iszero(interval)));
+
+ /*
+ * Get current time.
+ */
+ if (type != isc_timertype_inactive) {
+ TIME_NOW(&now);
+ } 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);
+ }
+
+ LOCK(&manager->lock);
+ LOCK(&timer->lock);
+
+ if (purge) {
+ timer_purge(timer);
+ }
+ 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, true);
+ }
+ }
+
+ UNLOCK(&timer->lock);
+ UNLOCK(&manager->lock);
+
+ return (result);
+}
+
+isc_timertype_t
+isc_timer_gettype(isc_timer_t *timer) {
+ isc_timertype_t t;
+
+ REQUIRE(VALID_TIMER(timer));
+
+ LOCK(&timer->lock);
+ t = timer->type;
+ UNLOCK(&timer->lock);
+
+ return (t);
+}
+
+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.
+ */
+
+ TIME_NOW(&now);
+ result = isc_time_add(&now, &timer->interval, &timer->idle);
+
+ UNLOCK(&timer->lock);
+
+ return (result);
+}
+
+void
+isc_timer_destroy(isc_timer_t **timerp) {
+ isc_timer_t *timer = NULL;
+ isc_timermgr_t *manager = NULL;
+
+ REQUIRE(timerp != NULL && VALID_TIMER(*timerp));
+
+ timer = *timerp;
+ *timerp = NULL;
+
+ manager = timer->manager;
+
+ LOCK(&manager->lock);
+
+ LOCK(&timer->lock);
+ timer_purge(timer);
+ deschedule(timer);
+ UNLOCK(&timer->lock);
+
+ UNLINK(manager->timers, timer, link);
+
+ UNLOCK(&manager->lock);
+
+ isc_task_detach(&timer->task);
+ isc_mutex_destroy(&timer->lock);
+ timer->magic = 0;
+ isc_mem_put(manager->mctx, timer, sizeof(*timer));
+}
+
+static void
+timer_post_event(isc_timermgr_t *manager, isc_timer_t *timer,
+ isc_eventtype_t type) {
+ isc_timerevent_t *event;
+ XTRACEID("posting", timer);
+
+ event = (isc_timerevent_t *)isc_event_allocate(
+ manager->mctx, timer, type, timer->action, timer->arg,
+ sizeof(*event));
+
+ ISC_LINK_INIT(event, ev_timerlink);
+ ((isc_event_t *)event)->ev_destroy = timerevent_destroy;
+ ((isc_event_t *)event)->ev_destroy_arg = timer;
+
+ event->due = timer->due;
+
+ LOCK(&timer->lock);
+ ISC_LIST_APPEND(timer->active, event, ev_timerlink);
+ UNLOCK(&timer->lock);
+
+ isc_task_send(timer->task, ISC_EVENT_PTR(&event));
+}
+
+static void
+dispatch(isc_timermgr_t *manager, isc_time_t *now) {
+ bool done = false, post_event, need_schedule;
+ isc_eventtype_t type = 0;
+ isc_timer_t *timer;
+ isc_result_t result;
+ bool idle;
+
+ /*!
+ * The caller must be holding the manager lock.
+ */
+
+ while (manager->nscheduled > 0 && !done) {
+ timer = isc_heap_element(manager->heap, 1);
+ INSIST(timer != NULL && 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 = true;
+ need_schedule = true;
+ } else if (timer->type == isc_timertype_limited) {
+ int cmp;
+ cmp = isc_time_compare(now, &timer->expires);
+ if (cmp >= 0) {
+ type = ISC_TIMEREVENT_LIFE;
+ post_event = true;
+ need_schedule = false;
+ } else {
+ type = ISC_TIMEREVENT_TICK;
+ post_event = true;
+ need_schedule = true;
+ }
+ } else if (!isc_time_isepoch(&timer->expires) &&
+ isc_time_compare(now, &timer->expires) >= 0)
+ {
+ type = ISC_TIMEREVENT_LIFE;
+ post_event = true;
+ need_schedule = false;
+ } else {
+ idle = false;
+
+ LOCK(&timer->lock);
+ if (!isc_time_isepoch(&timer->idle) &&
+ isc_time_compare(now, &timer->idle) >= 0)
+ {
+ idle = true;
+ }
+ UNLOCK(&timer->lock);
+ if (idle) {
+ type = ISC_TIMEREVENT_IDLE;
+ post_event = true;
+ need_schedule = false;
+ } else {
+ /*
+ * Idle timer has been touched;
+ * reschedule.
+ */
+ XTRACEID("idle reschedule", timer);
+ post_event = false;
+ need_schedule = true;
+ }
+ }
+
+ if (post_event) {
+ timer_post_event(manager, timer, type);
+ }
+
+ timer->index = 0;
+ isc_heap_delete(manager->heap, 1);
+ manager->nscheduled--;
+
+ if (need_schedule) {
+ result = schedule(timer, now, false);
+ if (result != ISC_R_SUCCESS) {
+ UNEXPECTED_ERROR(
+ "couldn't schedule timer: %s",
+ isc_result_totext(result));
+ }
+ }
+ } else {
+ manager->due = timer->due;
+ done = true;
+ }
+ }
+}
+
+static isc_threadresult_t
+run(void *uap) {
+ isc_timermgr_t *manager = uap;
+ isc_time_t now;
+ isc_result_t result;
+
+ LOCK(&manager->lock);
+ while (!manager->done) {
+ TIME_NOW(&now);
+
+ XTRACETIME("running", now);
+
+ dispatch(manager, &now);
+
+ if (manager->nscheduled > 0) {
+ XTRACETIME2("waituntil", manager->due, now);
+ result = WAITUNTIL(&manager->wakeup, &manager->lock,
+ &manager->due);
+ INSIST(result == ISC_R_SUCCESS ||
+ result == ISC_R_TIMEDOUT);
+ } else {
+ XTRACETIME("wait", now);
+ WAIT(&manager->wakeup, &manager->lock);
+ }
+ XTRACE("wakeup");
+ }
+ UNLOCK(&manager->lock);
+
+ return ((isc_threadresult_t)0);
+}
+
+static bool
+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 (true);
+ }
+ return (false);
+}
+
+static void
+set_index(void *what, unsigned int index) {
+ isc_timer_t *timer;
+
+ REQUIRE(VALID_TIMER(what));
+ timer = what;
+
+ timer->index = index;
+}
+
+isc_result_t
+isc__timermgr_create(isc_mem_t *mctx, isc_timermgr_t **managerp) {
+ isc_timermgr_t *manager;
+
+ /*
+ * Create a timer manager.
+ */
+
+ REQUIRE(managerp != NULL && *managerp == NULL);
+
+ manager = isc_mem_get(mctx, sizeof(*manager));
+
+ manager->magic = TIMER_MANAGER_MAGIC;
+ manager->mctx = NULL;
+ manager->done = false;
+ INIT_LIST(manager->timers);
+ manager->nscheduled = 0;
+ isc_time_settoepoch(&manager->due);
+ manager->heap = NULL;
+ isc_heap_create(mctx, sooner, set_index, 0, &manager->heap);
+ isc_mutex_init(&manager->lock);
+ isc_mem_attach(mctx, &manager->mctx);
+ isc_condition_init(&manager->wakeup);
+ isc_thread_create(run, manager, &manager->thread);
+ isc_thread_setname(manager->thread, "isc-timer");
+
+ *managerp = manager;
+
+ return (ISC_R_SUCCESS);
+}
+
+void
+isc_timermgr_poke(isc_timermgr_t *manager) {
+ REQUIRE(VALID_MANAGER(manager));
+
+ SIGNAL(&manager->wakeup);
+}
+
+void
+isc__timermgr_destroy(isc_timermgr_t **managerp) {
+ isc_timermgr_t *manager;
+
+ /*
+ * Destroy a timer manager.
+ */
+
+ REQUIRE(managerp != NULL);
+ manager = *managerp;
+ REQUIRE(VALID_MANAGER(manager));
+
+ LOCK(&manager->lock);
+
+ REQUIRE(EMPTY(manager->timers));
+ manager->done = true;
+
+ XTRACE("signal (destroy)");
+ SIGNAL(&manager->wakeup);
+
+ UNLOCK(&manager->lock);
+
+ /*
+ * Wait for thread to exit.
+ */
+ isc_thread_join(manager->thread, NULL);
+
+ /*
+ * Clean up.
+ */
+ (void)isc_condition_destroy(&manager->wakeup);
+ isc_mutex_destroy(&manager->lock);
+ isc_heap_destroy(&manager->heap);
+ manager->magic = 0;
+ isc_mem_putanddetach(&manager->mctx, manager, sizeof(*manager));
+
+ *managerp = NULL;
+}
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