Add shutdown signaling for catalog zones

This change should make sure that catalog zone update processing
doesn't happen when the catalog zone is being shut down. This
should help avoid races when offloading the catalog zone updates
in the follow-up commit.

diff --git a/lib/dns/catz.c b/lib/dns/catz.c
index 39c1b55c809adff2cfca0cd8c548a34b9e070ff1..ef1beb7b39c4c037e3cff4482a223969be514d9e 100644 (file)
--- a/lib/dns/catz.c
+++ b/lib/dns/catz.c
@@ -69,6 +69,7 @@ struct dns_catz_entry {
  */
 struct dns_catz_zone {
        unsigned int magic;
+       isc_loop_t *loop;
        dns_name_t name;
        dns_catz_zones_t *catzs;
        dns_rdata_t soa;
@@ -101,6 +102,8 @@ struct dns_catz_zone {
 
 static void
 dns__catz_timer_start(dns_catz_zone_t *catz);
+static void
+dns__catz_timer_stop(void *arg);
 
 static isc_result_t
 catz_process_zones_entry(dns_catz_zone_t *catz, dns_rdataset_t *value,
@@ -126,6 +129,7 @@ struct dns_catz_zones {
        dns_catz_zonemodmethods_t *zmm;
        isc_loopmgr_t *loopmgr;
        dns_view_t *view;
+       atomic_bool shuttingdown;
 };
 
 void
@@ -820,11 +824,26 @@ dns__catz_timer_start(dns_catz_zone_t *catz) {
                isc_interval_set(&interval, 0, 0);
        }
 
-       isc_timer_create(isc_loop_current(catz->catzs->loopmgr),
-                        dns_catz_update_action, catz, &catz->updatetimer);
+       catz->loop = isc_loop_current(catz->catzs->loopmgr);
+
+       isc_timer_create(catz->loop, dns_catz_update_action, catz,
+                        &catz->updatetimer);
        isc_timer_start(catz->updatetimer, isc_timertype_once, &interval);
 }
 
+static void
+dns__catz_timer_stop(void *arg) {
+       dns_catz_zone_t *catz = arg;
+       REQUIRE(DNS_CATZ_ZONE_VALID(catz));
+
+       isc_timer_stop(catz->updatetimer);
+       isc_timer_destroy(&catz->updatetimer);
+       catz->loop = NULL;
+
+       dns_catz_unref_catzs(catz->catzs);
+       dns_catz_detach_catz(&catz);
+}
+
 isc_result_t
 dns_catz_add_zone(dns_catz_zones_t *catzs, const dns_name_t *name,
                  dns_catz_zone_t **catzp) {
@@ -888,6 +907,20 @@ dns_catz_get_zone(dns_catz_zones_t *catzs, const dns_name_t *name) {
        return (found);
 }
 
+static void
+dns__catz_shutdown(dns_catz_zone_t *catz) {
+       /* lock must be locked */
+       if (catz->updatetimer != NULL) {
+               /* Don't wait for timer to trigger for shutdown */
+               INSIST(catz->loop != NULL);
+
+               dns_catz_ref_catzs(catz->catzs);
+               isc_async_run(catz->loop, dns__catz_timer_stop, catz);
+       } else {
+               dns_catz_detach_catz(&catz);
+       }
+}
+
 static void
 dns__catz_zone_destroy(dns_catz_zone_t *catz) {
        isc_mem_t *mctx = catz->catzs->mctx;
@@ -959,27 +992,44 @@ dns__catz_zone_destroy(dns_catz_zone_t *catz) {
 
 static void
 dns__catz_zones_destroy(dns_catz_zones_t *catzs) {
+       REQUIRE(atomic_load(&catzs->shuttingdown));
+       REQUIRE(catzs->zones == NULL);
+
+       catzs->magic = 0;
+       isc_mutex_destroy(&catzs->lock);
+       isc_refcount_destroy(&catzs->references);
+
+       isc_mem_putanddetach(&catzs->mctx, catzs, sizeof(*catzs));
+}
+
+void
+dns_catz_shutdown_catzs(dns_catz_zones_t *catzs) {
+       REQUIRE(DNS_CATZ_ZONES_VALID(catzs));
+
+       if (!atomic_compare_exchange_strong(&catzs->shuttingdown,
+                                           &(bool){ false }, true))
+       {
+               return;
+       }
+
+       LOCK(&catzs->lock);
        if (catzs->zones != NULL) {
                isc_ht_iter_t *iter = NULL;
                isc_result_t result;
                isc_ht_iter_create(catzs->zones, &iter);
                for (result = isc_ht_iter_first(iter); result == ISC_R_SUCCESS;)
                {
-                       dns_catz_zone_t *zone = NULL;
-                       isc_ht_iter_current(iter, (void **)&zone);
+                       dns_catz_zone_t *catz = NULL;
+                       isc_ht_iter_current(iter, (void **)&catz);
                        result = isc_ht_iter_delcurrent_next(iter);
-                       dns_catz_detach_catz(&zone);
+                       dns__catz_shutdown(catz);
                }
                INSIST(result == ISC_R_NOMORE);
                isc_ht_iter_destroy(&iter);
                INSIST(isc_ht_count(catzs->zones) == 0);
                isc_ht_destroy(&catzs->zones);
        }
-       catzs->magic = 0;
-       isc_mutex_destroy(&catzs->lock);
-       isc_refcount_destroy(&catzs->references);
-
-       isc_mem_putanddetach(&catzs->mctx, catzs, sizeof(*catzs));
+       UNLOCK(&catzs->lock);
 }
 
 #ifdef DNS_CATZ_TRACE
@@ -1991,6 +2041,7 @@ dns_catz_update_action(void *arg) {
        dns_catz_update_from_db(catz->db, catz->catzs);
        isc_timer_stop(catz->updatetimer);
        isc_timer_destroy(&catz->updatetimer);
+       catz->loop = NULL;
        result = isc_time_now(&catz->lastupdated);
        RUNTIME_CHECK(result == ISC_R_SUCCESS);
        UNLOCK(&catz->catzs->lock);
@@ -2083,6 +2134,10 @@ dns_catz_update_from_db(dns_db_t *db, dns_catz_zones_t *catzs) {
        REQUIRE(DNS_DB_VALID(db));
        REQUIRE(DNS_CATZ_ZONES_VALID(catzs));
 
+       if (atomic_load(&catzs->shuttingdown)) {
+               return;
+       }
+
        dns_name_format(&db->origin, bname, DNS_NAME_FORMATSIZE);
 
        /*

diff --git a/lib/dns/include/dns/catz.h b/lib/dns/include/dns/catz.h
index 97ee94d56fec10d34cc1f344e32d2c2569aa3554..67f96e2d21cd2f48bc96c74639ec2eee3571f884 100644 (file)
--- a/lib/dns/include/dns/catz.h
+++ b/lib/dns/include/dns/catz.h
@@ -438,6 +438,16 @@ dns_catz_get_iterator(dns_catz_zone_t *catz, isc_ht_iter_t **itp);
  *
  */
 
+void
+dns_catz_shutdown_catzs(dns_catz_zones_t *catzs);
+/*%<
+ * Shut down the catalog zones.
+ *
+ * Requires:
+ * \li 'catzs' is a valid dns_catz_zones_t.
+ *
+ */
+
 #ifdef DNS_CATZ_TRACE
 /* Compatibility macros */
 #define dns_catz_attach_catz(catz, catzp) \

diff --git a/lib/dns/view.c b/lib/dns/view.c
index 0d3580adc683c3cbd9fafe5ec3d704482c7b8613..0cf2a4802eda4dda8f12b42ba47c618dea7446a2 100644 (file)
--- a/lib/dns/view.c
+++ b/lib/dns/view.c
@@ -300,6 +300,7 @@ destroy(dns_view_t *view) {
                dns_rpz_detach_rpzs(&view->rpzs);
        }
        if (view->catzs != NULL) {
+               dns_catz_shutdown_catzs(view->catzs);
                dns_catz_detach_catzs(&view->catzs);
        }
        for (dlzdb = ISC_LIST_HEAD(view->dlz_searched); dlzdb != NULL;
@@ -548,6 +549,7 @@ dns_view_detach(dns_view_t **viewp) {
                        }
                }
                if (view->catzs != NULL) {
+                       dns_catz_shutdown_catzs(view->catzs);
                        dns_catz_detach_catzs(&view->catzs);
                }
                if (view->ntatable_priv != NULL) {