home: fix more

internal/home/dns.go

@@ -502,9 +502,6 @@ func closeDNSServer() {
 		if err != nil {
 			log.Debug("closing stats: %s", err)
 		}
-
-		// TODO(e.burkov):  Find out if it's safe.
-		Context.stats = nil
 	}
 
 	if Context.queryLog != nil {

internal/home/home.go

@@ -14,6 +14,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"sync"
+	"sync/atomic"
 	"syscall"
 	"time"
 
@@ -101,6 +102,19 @@ func Main(clientBuildFS fs.FS) {
 
 	signals := make(chan os.Signal, 1)
 	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP, syscall.SIGQUIT)
+
+	// TODO(s.chzhen):  Think of better way to do graceful shutdown.
+	var cleaningMu sync.Mutex
+	cleanExit := func() {
+		cleaningMu.Lock()
+		defer cleaningMu.Unlock()
+
+		cleanup(context.Background())
+		cleanupAlways()
+
+		os.Exit(0)
+	}
+
 	go func() {
 		for {
 			sig := <-signals
@@ -110,15 +124,17 @@ func Main(clientBuildFS fs.FS) {
 				Context.clients.reloadARP()
 				Context.tls.reload()
 			default:
-				cleanup(context.Background())
-				cleanupAlways()
-				os.Exit(0)
+				cleanExit()
 			}
 		}
 	}()
 
 	if opts.serviceControlAction != "" {
-		handleServiceControlAction(opts, clientBuildFS, signals)
+		isStopping := new(atomic.Bool)
+		handleServiceControlAction(opts, clientBuildFS, isStopping)
+		if isStopping.Load() {
+			cleanExit()
+		}
 
 		return
 	}

internal/home/service.go

@@ -7,6 +7,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync/atomic"
 	"syscall"
 	"time"
 
@@ -33,7 +34,7 @@ const (
 // daemon.
 type program struct {
 	clientBuildFS fs.FS
-	signals       chan os.Signal
+	isStopping    *atomic.Bool
 	opts          options
 }
 
@@ -53,12 +54,7 @@ func (p *program) Start(_ service.Service) (err error) {
 
 // Stop implements service.Interface interface for *program.
 func (p *program) Stop(_ service.Service) (err error) {
-	select {
-	case p.signals <- syscall.SIGINT:
-		// Go on.
-	default:
-		// Stop should not block.
-	}
+	p.isStopping.Store(true)
 
 	return nil
 }
@@ -198,7 +194,7 @@ func restartService() (err error) {
 //   - run:  This is a special command that is not supposed to be used directly
 //     it is specified when we register a service, and it indicates to the app
 //     that it is being run as a service/daemon.
-func handleServiceControlAction(opts options, clientBuildFS fs.FS, signals chan os.Signal) {
+func handleServiceControlAction(opts options, clientBuildFS fs.FS, isStopping *atomic.Bool) {
 	// Call chooseSystem explicitly to introduce OpenBSD support for service
 	// package.  It's a noop for other GOOS values.
 	chooseSystem()
@@ -232,7 +228,7 @@ func handleServiceControlAction(opts options, clientBuildFS fs.FS, signals chan
 
 	s, err := service.New(&program{
 		clientBuildFS: clientBuildFS,
-		signals:       signals,
+		isStopping:    isStopping,
 		opts:          runOpts,
 	}, svcConfig)
 	if err != nil {