From 8e3c16175a09c9955faee451fa20db38c68e90fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <michal@isc.org>
Date: Mon, 5 Feb 2018 21:22:53 +0100
Subject: [PATCH] Make dns_dt_reopen() request task-exclusive mode on its own

Instead of relying on the caller to set up task-exclusive mode, make
dns_dt_reopen() enforce task-exclusive mode itself, using the task
specified at dnstap environment creation time.
---
 bin/named/server.c           |  8 +++-----
 lib/dns/dnstap.c             | 10 ++++++++++
 lib/dns/include/dns/dnstap.h |  3 ++-
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/bin/named/server.c b/bin/named/server.c
index 3c17063a00..89cf2800b6 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -3549,8 +3549,9 @@ configure_dnstap(const cfg_obj_t **maps, dns_view_t *view) {
 			fstrm_iothr_options_set_reopen_interval(fopt, i);
 		}
 
-		CHECKM(dns_dt_create(named_g_mctx, dmode, dpath,
-				     &fopt, &named_g_server->dtenv),
+		CHECKM(dns_dt_create2(named_g_mctx, dmode, dpath,
+				      &fopt, named_g_server->task,
+				      &named_g_server->dtenv),
 		       "unable to create dnstap environment");
 
 		CHECKM(dns_dt_setupfile(named_g_server->dtenv,
@@ -14825,10 +14826,7 @@ named_server_dnstap(named_server_t *server, isc_lex_t *lex,
 		return (DNS_R_SYNTAX);
 	}
 
-	result = isc_task_beginexclusive(server->task);
-	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 	result = dns_dt_reopen(server->dtenv, backups);
-	isc_task_endexclusive(server->task);
 	return (result);
 #else
 	UNUSED(server);
diff --git a/lib/dns/dnstap.c b/lib/dns/dnstap.c
index 37da384303..6973a0b2d3 100644
--- a/lib/dns/dnstap.c
+++ b/lib/dns/dnstap.c
@@ -55,6 +55,7 @@
 #include <isc/once.h>
 #include <isc/print.h>
 #include <isc/sockaddr.h>
+#include <isc/task.h>
 #include <isc/thread.h>
 #include <isc/time.h>
 #include <isc/types.h>
@@ -331,11 +332,18 @@ dns_dt_reopen(dns_dtenv_t *env, int roll) {
 
 	REQUIRE(VALID_DTENV(env));
 
+	/*
+	 * Run in task-exclusive mode.
+	 */
+	result = isc_task_beginexclusive(env->reopen_task);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
 	/*
 	 * Check that we can create a new fw object.
 	 */
 	fwopt = fstrm_writer_options_init();
 	if (fwopt == NULL) {
+		isc_task_endexclusive(env->reopen_task);
 		return (ISC_R_NOMEMORY);
 	}
 
@@ -424,6 +432,8 @@ dns_dt_reopen(dns_dtenv_t *env, int roll) {
 	if (fuwopt != NULL)
 		fstrm_unix_writer_options_destroy(&fuwopt);
 
+	isc_task_endexclusive(env->reopen_task);
+
 	return (result);
 }
 
diff --git a/lib/dns/include/dns/dnstap.h b/lib/dns/include/dns/dnstap.h
index b4002fc9a2..38e1e0449a 100644
--- a/lib/dns/include/dns/dnstap.h
+++ b/lib/dns/include/dns/dnstap.h
@@ -195,7 +195,8 @@ dns_dt_reopen(dns_dtenv_t *env, int roll);
  * keep.  If 'roll' is negative, or if 'env->mode' is dns_dtmode_unix,
  * then the channel is simply reopened.
  *
- * Note: dns_dt_reopen() must be called in task exclusive mode.
+ * Note: dns_dt_reopen() uses task-exclusive mode and must be run in the
+ * context of env->reopen_task.
  *
  * Requires:
  *\li	'env' is a valid dnstap environment.