From 27850a5ad236650dfde77ffa1f4f3015e8ec830a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Fri, 11 Mar 2022 22:34:45 +0100
Subject: [PATCH] Change isc_timer_reset() usage to never use expires argument

There were two places where expires argument (absolute isc_time_t value)
was being used.  Both places has been converted to use relative interval
argument in preparation of simplification and refactoring of isc_timer
API.
---
 lib/dns/resolver.c | 47 +++++++++++++++++++++++++++-------------------
 lib/dns/zone.c     | 20 +++++++++++++++++---
 lib/isc/timer.c    |  4 ++--
 3 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index a81e4285ef..1f1b5efad9 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -337,7 +337,6 @@ struct fetchctx {
 	isc_time_t expires;
 	isc_time_t expires_try_stale;
 	isc_time_t next_timeout;
-	isc_time_t final;
 	isc_interval_t interval;
 	dns_message_t *qmessage;
 	ISC_LIST(resquery_t) queries;
@@ -1255,8 +1254,27 @@ update_edns_stats(resquery_t *query) {
  */
 static inline isc_result_t
 fctx_starttimer(fetchctx_t *fctx) {
-	return (isc_timer_reset(fctx->timer, isc_timertype_once, &fctx->final,
-				NULL, true));
+	isc_interval_t interval;
+	isc_time_t now;
+	isc_time_t expires;
+
+	isc_interval_set(&interval, 2, 0);
+	isc_time_add(&fctx->expires, &interval, &expires);
+
+	isc_time_now(&now);
+	if (isc_time_compare(&expires, &now) <= 0) {
+		isc_interval_set(&interval, 0, 1);
+	} else {
+		isc_time_t tmp;
+		isc_interval_set(&interval, isc_time_seconds(&now),
+				 isc_time_nanoseconds(&now));
+		isc_time_subtract(&expires, &interval, &tmp);
+		isc_interval_set(&interval, isc_time_seconds(&tmp),
+				 isc_time_nanoseconds(&tmp));
+	}
+
+	return (isc_timer_reset(fctx->timer, isc_timertype_once, NULL,
+				&interval, true));
 }
 
 static inline void
@@ -4533,6 +4551,13 @@ fctx_start(isc_task_t *task, isc_event_t *event) {
 
 	UNLOCK(&res->buckets[bucketnum].lock);
 
+	/*
+	 * As a backstop, we also set a timer to stop the fetch
+	 * if in-band netmgr timeouts don't work. It will fire two
+	 * seconds after the fetch should have finished. (This
+	 * should be enough of a gap to avoid the timer firing
+	 * while a response is being processed normally.)
+	 */
 	result = fctx_starttimer(fctx);
 	if (result != ISC_R_SUCCESS) {
 		fctx_done(fctx, result, __LINE__);
@@ -4836,22 +4861,6 @@ fctx_create(dns_resolver_t *res, isc_task_t *task, const dns_name_t *name,
 		goto cleanup_qmessage;
 	}
 
-	/*
-	 * As a backstop, we also set a timer to stop the fetch
-	 * if in-band netmgr timeouts don't work. It will fire two
-	 * seconds after the fetch should have finished. (This
-	 * should be enough of a gap to avoid the timer firing
-	 * while a response is being processed normally.)
-	 */
-	isc_interval_set(&interval, 2, 0);
-	iresult = isc_time_add(&fctx->expires, &interval, &fctx->final);
-	if (iresult != ISC_R_SUCCESS) {
-		UNEXPECTED_ERROR(__FILE__, __LINE__, "isc_time_add: %s",
-				 isc_result_totext(iresult));
-		result = ISC_R_UNEXPECTED;
-		goto cleanup_qmessage;
-	}
-
 	/*
 	 * Create an inactive timer to enforce maximum query
 	 * lifetime. It will be made active when the fetch is
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 304bfb5a32..4d2178e66e 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -15279,11 +15279,25 @@ zone_settimer(dns_zone_t *zone, isc_time_t *now) {
 				     isc_result_totext(result));
 		}
 	} else {
+		isc_interval_t interval;
 		if (isc_time_compare(&next, now) <= 0) {
-			next = *now;
+			isc_interval_set(&interval, 0, 1);
+		} else {
+			/*
+			 * In theory, we could just type isc_interval_t to
+			 * isc_time_t and back, but there's no such guarantee,
+			 * so a safer method is being used here.
+			 */
+			isc_time_t tmp;
+			isc_interval_set(&interval, isc_time_seconds(now),
+					 isc_time_nanoseconds(now));
+			isc_time_subtract(&next, &interval, &tmp);
+			isc_interval_set(&interval, isc_time_seconds(&tmp),
+					 isc_time_nanoseconds(&tmp));
 		}
-		result = isc_timer_reset(zone->timer, isc_timertype_once, &next,
-					 NULL, true);
+
+		result = isc_timer_reset(zone->timer, isc_timertype_once, NULL,
+					 &interval, true);
 		if (result != ISC_R_SUCCESS) {
 			dns_zone_log(zone, ISC_LOG_ERROR,
 				     "could not reset zone timer: %s",
diff --git a/lib/isc/timer.c b/lib/isc/timer.c
index 17322b2e44..ae6d20552a 100644
--- a/lib/isc/timer.c
+++ b/lib/isc/timer.c
@@ -92,7 +92,7 @@ struct isc_timermgr {
 	isc_heap_t *heap;
 };
 
-static inline isc_result_t
+static isc_result_t
 schedule(isc_timer_t *timer, isc_time_t *now, bool signal_ok) {
 	isc_timermgr_t *manager;
 	isc_time_t due;
@@ -170,7 +170,7 @@ schedule(isc_timer_t *timer, isc_time_t *now, bool signal_ok) {
 	return (ISC_R_SUCCESS);
 }
 
-static inline void
+static void
 deschedule(isc_timer_t *timer) {
 	isc_timermgr_t *manager;