[master] don't keep an LMDB transaction open across an exclusive section

4625.	[bug]		Running "rndc addzone" and "rndc delzone" at close
			to the same time could trigger a deadlock if using
			LMDB. [RT #45209]

diff --git a/CHANGES b/CHANGES
index 0c7e631859548e5eb950f8477ea830ebba14c858..7d89538a2851629a20e7a8098fe939c73493aafb 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+4625.  [bug]           Running "rndc addzone" and "rndc delzone" at close
+                       to the same time could trigger a deadlock if using
+                       LMDB. [RT #45209]
+
 4624.  [placeholder]
 
 4623.  [bug]           Use --with-protobuf-c and --with-libfstrm to find

diff --git a/bin/named/server.c b/bin/named/server.c
index 46641bc15cc5c1b5c3f6b9a7bf265a6b96fdc9f1..30d54ff8d2ef4f49a65200ed6258a87b38de89b8 100644 (file)
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -478,6 +478,9 @@ count_zones(const cfg_obj_t *conf);
 static isc_result_t
 migrate_nzf(dns_view_t *view);
 
+static isc_result_t
+nzd_writable(dns_view_t *view);
+
 static isc_result_t
 nzd_open(dns_view_t *view, unsigned int flags, MDB_txn **txnp, MDB_dbi *dbi);
 
@@ -11239,6 +11242,37 @@ nzd_save(MDB_txn **txnp, MDB_dbi dbi, dns_zone_t *zone,
        return (result);
 }
 
+static isc_result_t
+nzd_writable(dns_view_t *view) {
+       isc_result_t result = ISC_R_SUCCESS;
+       int status;
+       MDB_dbi dbi;
+       MDB_txn *txn = NULL;
+
+       REQUIRE(view != NULL);
+
+       status = mdb_txn_begin((MDB_env *) view->new_zone_dbenv, 0, 0, &txn);
+       if (status != 0) {
+               isc_log_write(ns_g_lctx,
+                             NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
+                             ISC_LOG_WARNING, "mdb_txn_begin: %s",
+                             mdb_strerror(status));
+               return (ISC_R_FAILURE);
+       }
+
+       status = mdb_dbi_open(txn, NULL, 0, &dbi);
+       if (status != 0) {
+               isc_log_write(ns_g_lctx,
+                     NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
+                             ISC_LOG_WARNING, "mdb_dbi_open: %s",
+                             mdb_strerror(status));
+               result = ISC_R_FAILURE;
+       }
+
+       mdb_txn_abort(txn);
+       return (result);
+}
+
 static isc_result_t
 nzd_open(dns_view_t *view, unsigned int flags, MDB_txn **txnp, MDB_dbi *dbi) {
        int status;
@@ -11711,7 +11745,7 @@ do_addzone(ns_server_t *server, ns_cfgctx_t *cfg, dns_view_t *view,
        fp = NULL;
 #else /* HAVE_LMDB */
        /* Make sure we can open the NZD database */
-       result = nzd_open(view, 0, &txn, &dbi);
+       result = nzd_writable(view);
        if (result != ISC_R_SUCCESS) {
                TCHECK(putstr(text, "unable to open NZD database for '"));
                TCHECK(putstr(text, view->new_zone_db));
@@ -11802,12 +11836,13 @@ do_addzone(ns_server_t *server, ns_cfgctx_t *cfg, dns_view_t *view,
        /* Flag the zone as having been added at runtime */
        dns_zone_setadded(zone, ISC_TRUE);
 
-#ifndef HAVE_LMDB
+#ifdef HAVE_LMDB
+       /* Save the new zone configuration into the NZD */
+       CHECK(nzd_open(view, 0, &txn, &dbi));
+       CHECK(nzd_save(&txn, dbi, zone, zoneobj));
+#else
        /* Append the zone configuration to the NZF */
        result = nzf_append(view, zoneobj);
-#else /* HAVE_LMDB */
-       /* Save the new zone configuration into the NZD */
-       result = nzd_save(&txn, dbi, zone, zoneobj);
 #endif /* HAVE_LMDB */
 
  cleanup:
@@ -11884,7 +11919,7 @@ do_modzone(ns_server_t *server, ns_cfgctx_t *cfg, dns_view_t *view,
        fp = NULL;
 #else /* HAVE_LMDB */
        /* Make sure we can open the NZD database */
-       result = nzd_open(view, 0, &txn, &dbi);
+       result = nzd_writable(view);
        if (result != ISC_R_SUCCESS) {
                TCHECK(putstr(text, "unable to open NZD database for '"));
                TCHECK(putstr(text, view->new_zone_db));
@@ -12001,15 +12036,16 @@ do_modzone(ns_server_t *server, ns_cfgctx_t *cfg, dns_view_t *view,
 #endif /* HAVE_LMDB */
 
        if (added) {
-#ifndef HAVE_LMDB
+#ifdef HAVE_LMDB
+               CHECK(nzd_open(view, 0, &txn, &dbi));
+               CHECK(nzd_save(&txn, dbi, zone, zoneobj));
+#else
                result = nzf_append(view, zoneobj);
                if (result != ISC_R_SUCCESS) {
                        TCHECK(putstr(text, "\nNew zone config not saved: "));
                        TCHECK(putstr(text, isc_result_totext(result)));
                        goto cleanup;
                }
-#else /* HAVE_LMDB */
-               nzd_save(&txn, dbi, zone, zoneobj);
 #endif /* HAVE_LMDB */
 
                TCHECK(putstr(text, "zone '"));