From a0e5fc733e412beb674f38d4b5994e443e63c937 Mon Sep 17 00:00:00 2001
From: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>
Date: Mon, 24 Jun 2024 15:05:25 +0300
Subject: [PATCH] [#1145] node/ir: Handle double SIGHUP correctly

Signed-off-by: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>
---
 cmd/frostfs-ir/config.go   | 39 ++++++++++++++++++++++++----------
 cmd/frostfs-node/config.go | 43 ++++++++++++++++++++++++++++----------
 2 files changed, 60 insertions(+), 22 deletions(-)

diff --git a/cmd/frostfs-ir/config.go b/cmd/frostfs-ir/config.go
index c3227a182..955195477 100644
--- a/cmd/frostfs-ir/config.go
+++ b/cmd/frostfs-ir/config.go
@@ -45,18 +45,41 @@ func reloadConfig() error {
 
 func watchForSignal(cancel func()) {
 	ch := make(chan os.Signal, 1)
-	signal.Notify(ch, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
+	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
+
+	sighupCh := make(chan os.Signal, 1)
+	signal.Notify(sighupCh, syscall.SIGHUP)
 
 	for {
 		select {
-		case err := <-intErr:
+		// signals causing application to shut down should have priority over
+		// reconfiguration signal
+		case <-ch:
+			log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
+			cancel()
+			shutdown()
+			log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
+			return
+		case err := <-intErr: // internal application error
 			log.Info(logs.FrostFSIRInternalError, zap.String("msg", err.Error()))
 			cancel()
 			shutdown()
 			return
-		case sig := <-ch:
-			switch sig {
-			case syscall.SIGHUP:
+		default:
+			// block until any signal is receieved
+			select {
+			case <-ch:
+				log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
+				cancel()
+				shutdown()
+				log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
+				return
+			case err := <-intErr: // internal application error
+				log.Info(logs.FrostFSIRInternalError, zap.String("msg", err.Error()))
+				cancel()
+				shutdown()
+				return
+			case <-sighupCh:
 				log.Info(logs.FrostFSNodeSIGHUPHasBeenReceivedRereadingConfiguration)
 				err := reloadConfig()
 				if err != nil {
@@ -70,12 +93,6 @@ func watchForSignal(cancel func()) {
 					log.Error(logs.FrostFSNodeConfigurationReading, zap.Error(err))
 				}
 				log.Info(logs.FrostFSNodeConfigurationHasBeenReloadedSuccessfully)
-			case syscall.SIGTERM, syscall.SIGINT:
-				log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
-				cancel()
-				shutdown()
-				log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
-				return
 			}
 		}
 	}
diff --git a/cmd/frostfs-node/config.go b/cmd/frostfs-node/config.go
index ef2c0424b..3aded7020 100644
--- a/cmd/frostfs-node/config.go
+++ b/cmd/frostfs-node/config.go
@@ -1224,22 +1224,22 @@ type dCmp struct {
 
 func (c *cfg) signalWatcher(ctx context.Context) {
 	ch := make(chan os.Signal, 1)
-	signal.Notify(ch, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
+	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
+
+	sighupCh := make(chan os.Signal, 1)
+	signal.Notify(sighupCh, syscall.SIGHUP)
 
 	for {
 		select {
-		case sig := <-ch:
-			switch sig {
-			case syscall.SIGHUP:
-				c.reloadConfig(ctx)
-			case syscall.SIGTERM, syscall.SIGINT:
-				c.log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
+		// signals causing application to shut down should have priority over
+		// reconfiguration signal
+		case <-ch:
+			c.log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
 
-				c.shutdown()
+			c.shutdown()
 
-				c.log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
-				return
-			}
+			c.log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
+			return
 		case err := <-c.internalErr: // internal application error
 			c.log.Warn(logs.FrostFSNodeInternalApplicationError,
 				zap.String("message", err.Error()))
@@ -1248,6 +1248,27 @@ func (c *cfg) signalWatcher(ctx context.Context) {
 
 			c.log.Info(logs.FrostFSNodeInternalErrorProcessingIsComplete)
 			return
+		default:
+			// block until any signal is receieved
+			select {
+			case <-sighupCh:
+				c.reloadConfig(ctx)
+			case <-ch:
+				c.log.Info(logs.FrostFSNodeTerminationSignalHasBeenReceivedStopping)
+
+				c.shutdown()
+
+				c.log.Info(logs.FrostFSNodeTerminationSignalProcessingIsComplete)
+				return
+			case err := <-c.internalErr: // internal application error
+				c.log.Warn(logs.FrostFSNodeInternalApplicationError,
+					zap.String("message", err.Error()))
+
+				c.shutdown()
+
+				c.log.Info(logs.FrostFSNodeInternalErrorProcessingIsComplete)
+				return
+			}
 		}
 	}
 }