From 7a40c42e8bc9e1fa8494dffcc2fa1cc5ab791167 Mon Sep 17 00:00:00 2001
From: Simon Frei <freisim93@gmail.com>
Date: Thu, 14 Feb 2019 00:07:27 +0100
Subject: [PATCH] cmd/syncthing: Introduce exiter to handle termination (#5532)

---
 cmd/syncthing/gui.go  |  9 ++++----
 cmd/syncthing/main.go | 51 +++++++++++++++++++++++++++----------------
 2 files changed, 36 insertions(+), 24 deletions(-)

diff --git a/cmd/syncthing/gui.go b/cmd/syncthing/gui.go
index 105d4258e..134e6fe0e 100644
--- a/cmd/syncthing/gui.go
+++ b/cmd/syncthing/gui.go
@@ -932,7 +932,7 @@ func (s *apiService) getSystemConfigInsync(w http.ResponseWriter, r *http.Reques
 
 func (s *apiService) postSystemRestart(w http.ResponseWriter, r *http.Request) {
 	s.flushResponse(`{"ok": "restarting"}`, w)
-	go restart()
+	go exit.Restart()
 }
 
 func (s *apiService) postSystemReset(w http.ResponseWriter, r *http.Request) {
@@ -958,12 +958,12 @@ func (s *apiService) postSystemReset(w http.ResponseWriter, r *http.Request) {
 		s.flushResponse(`{"ok": "resetting folder `+folder+`"}`, w)
 	}
 
-	go restart()
+	go exit.Restart()
 }
 
 func (s *apiService) postSystemShutdown(w http.ResponseWriter, r *http.Request) {
 	s.flushResponse(`{"ok": "shutting down"}`, w)
-	go shutdown()
+	go exit.Shutdown()
 }
 
 func (s *apiService) flushResponse(resp string, w http.ResponseWriter) {
@@ -1383,8 +1383,7 @@ func (s *apiService) postSystemUpgrade(w http.ResponseWriter, r *http.Request) {
 		}
 
 		s.flushResponse(`{"ok": "restarting"}`, w)
-		l.Infoln("Upgrading")
-		stop <- exitUpgrading
+		exit.ExitUpgrading()
 	}
 }
 
diff --git a/cmd/syncthing/main.go b/cmd/syncthing/main.go
index 8f0b9244c..7a3a84604 100644
--- a/cmd/syncthing/main.go
+++ b/cmd/syncthing/main.go
@@ -68,10 +68,7 @@ const (
 	maxSystemLog         = 250
 )
 
-var (
-	myID protocol.DeviceID
-	stop = make(chan int)
-)
+var myID protocol.DeviceID
 
 const (
 	usage      = "syncthing [options]"
@@ -264,6 +261,32 @@ func parseCommandLineOptions() RuntimeOptions {
 	return options
 }
 
+type exiter struct {
+	stop chan int
+}
+
+func (e *exiter) Restart() {
+	l.Infoln("Restarting")
+	e.stop <- exitRestarting
+}
+
+func (e *exiter) Shutdown() {
+	l.Infoln("Shutting down")
+	e.stop <- exitSuccess
+}
+
+func (e *exiter) ExitUpgrading() {
+	l.Infoln("Shutting down after upgrade")
+	e.stop <- exitUpgrading
+}
+
+// waitForExit must be called synchronously.
+func (e *exiter) waitForExit() int {
+	return <-e.stop
+}
+
+var exit = exiter{make(chan int)}
+
 func main() {
 	options := parseCommandLineOptions()
 	l.SetFlags(options.logFlags)
@@ -858,7 +881,7 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		}
 	}
 
-	code := <-stop
+	code := exit.waitForExit()
 
 	mainService.Stop()
 
@@ -879,7 +902,7 @@ func setupSignalHandling() {
 	signal.Notify(restartSign, sigHup)
 	go func() {
 		<-restartSign
-		stop <- exitRestarting
+		exit.Restart()
 	}()
 
 	// Exit with "success" code (no restart) on INT/TERM
@@ -889,7 +912,7 @@ func setupSignalHandling() {
 	signal.Notify(stopSign, os.Interrupt, sigTerm)
 	go func() {
 		<-stopSign
-		stop <- exitSuccess
+		exit.Shutdown()
 	}()
 }
 
@@ -1034,16 +1057,6 @@ func resetDB() error {
 	return os.RemoveAll(locations.Get(locations.Database))
 }
 
-func restart() {
-	l.Infoln("Restarting")
-	stop <- exitRestarting
-}
-
-func shutdown() {
-	l.Infoln("Shutting down")
-	stop <- exitSuccess
-}
-
 func ensureDir(dir string, mode fs.FileMode) {
 	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 	err := fs.MkdirAll(".", mode)
@@ -1079,7 +1092,7 @@ func standbyMonitor() {
 			// things a moment to stabilize.
 			time.Sleep(restartDelay)
 
-			restart()
+			exit.Restart()
 			return
 		}
 		now = time.Now()
@@ -1137,7 +1150,7 @@ func autoUpgrade(cfg *config.Wrapper) {
 		events.Default.Unsubscribe(sub)
 		l.Warnf("Automatically upgraded to version %q. Restarting in 1 minute.", rel.Tag)
 		time.Sleep(time.Minute)
-		stop <- exitUpgrading
+		exit.ExitUpgrading()
 		return
 	}
 }