From d7416bb472b14dc317cd0f2ee0a8fc3d4082623e Mon Sep 17 00:00:00 2001
From: Colin Vidal <colin@isc.org>
Date: Tue, 22 Apr 2025 15:41:39 +0200
Subject: [PATCH] ignore reload request if in a reload process

Ignore an 'rndc reload' or 'rndc reconfig' command if received by named
while the server is currently reloading itself.
---
 bin/named/control.c              |  2 +-
 bin/named/include/named/server.h |  2 +-
 bin/named/server.c               | 36 ++++++++++++++++++++++++++++----
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/bin/named/control.c b/bin/named/control.c
index 10a4e00fc4..b5f7c49a80 100644
--- a/bin/named/control.c
+++ b/bin/named/control.c
@@ -252,7 +252,7 @@ named_control_docommand(isccc_sexpr_t *message, bool readonly,
 						  "query logging",
 						  NS_SERVER_LOGQUERIES, lex);
 	} else if (command_compare(command, NAMED_COMMAND_RECONFIG)) {
-		result = named_server_reconfigcommand(named_g_server);
+		result = named_server_reconfigcommand(named_g_server, *text);
 	} else if (command_compare(command, NAMED_COMMAND_RECURSING)) {
 		result = named_server_dumprecursing(named_g_server);
 	} else if (command_compare(command, NAMED_COMMAND_REFRESH)) {
diff --git a/bin/named/include/named/server.h b/bin/named/include/named/server.h
index a3aff6df94..7be62eecc7 100644
--- a/bin/named/include/named/server.h
+++ b/bin/named/include/named/server.h
@@ -161,7 +161,7 @@ named_server_resetstatscommand(named_server_t *server, isc_lex_t *lex,
  */
 
 isc_result_t
-named_server_reconfigcommand(named_server_t *server);
+named_server_reconfigcommand(named_server_t *server, isc_buffer_t *text);
 /*%<
  * Act on a "reconfig" command from the command channel.
  */
diff --git a/bin/named/server.c b/bin/named/server.c
index d5be63179a..ec9a1aea35 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -9924,8 +9924,16 @@ loadconfig(named_server_t *server) {
 static isc_result_t
 reload(named_server_t *server) {
 	isc_result_t result;
+	int reloadstatus = atomic_exchange(&server->reload_status,
+					   NAMED_RELOAD_IN_PROGRESS);
 
-	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
+	if (reloadstatus == NAMED_RELOAD_IN_PROGRESS) {
+		isc_log_write(NAMED_LOGCATEGORY_GENERAL, NAMED_LOGMODULE_SERVER,
+			      ISC_LOG_WARNING,
+			      "reload request ignored: already running");
+		result = ISC_R_ALREADYRUNNING;
+		goto cleanup;
+	}
 
 	named_os_notify_systemd("RELOADING=1\n"
 				"MONOTONIC_USEC=%" PRIu64 "\n"
@@ -10325,8 +10333,16 @@ named_server_reloadcommand(named_server_t *server, isc_lex_t *lex,
 	}
 	if (zone == NULL) {
 		result = reload(server);
-		if (result == ISC_R_SUCCESS) {
+		switch (result) {
+		case ISC_R_SUCCESS:
 			msg = "server reload successful";
+			break;
+		case ISC_R_ALREADYRUNNING:
+			msg = "reload request ignored as the server is "
+			      "currently being reloaded or reconfigured";
+			break;
+		default:
+			break;
 		}
 	} else {
 		type = dns_zone_gettype(zone);
@@ -10416,9 +10432,21 @@ named_server_resetstatscommand(named_server_t *server, isc_lex_t *lex,
  * Act on a "reconfig" command from the command channel.
  */
 isc_result_t
-named_server_reconfigcommand(named_server_t *server) {
+named_server_reconfigcommand(named_server_t *server, isc_buffer_t *text) {
 	isc_result_t result;
-	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
+	int reloadstatus = atomic_exchange(&server->reload_status,
+					   NAMED_RELOAD_IN_PROGRESS);
+
+	if (reloadstatus == NAMED_RELOAD_IN_PROGRESS) {
+		isc_log_write(NAMED_LOGCATEGORY_GENERAL, NAMED_LOGMODULE_SERVER,
+			      ISC_LOG_WARNING,
+			      "reconfig request ignored: already running");
+		result = ISC_R_ALREADYRUNNING;
+		isc_buffer_printf(text,
+				  "reconfig request ignored as the server is "
+				  "currently being reloaded or reconfigured");
+		goto cleanup;
+	}
 
 	named_os_notify_systemd("RELOADING=1\n"
 				"MONOTONIC_USEC=%" PRIu64 "\n"