cmd/syncthing: Always use monitor process (fixes #4774, fixes #5786) (#6278)

cmd/syncthing/main.go

@@ -47,6 +47,7 @@ import (
 const (
 	tlsDefaultCommonName   = "syncthing"
 	deviceCertLifetimeDays = 20 * 365
+	sigTerm                = syscall.Signal(15)
 )
 
 const (
@@ -225,7 +226,7 @@ func parseCommandLineOptions() RuntimeOptions {
 	flag.BoolVar(&options.Verbose, "verbose", false, "Print verbose log output")
 	flag.BoolVar(&options.paused, "paused", false, "Start with all devices and folders paused")
 	flag.BoolVar(&options.unpaused, "unpaused", false, "Start with all devices and folders unpaused")
-	flag.StringVar(&options.logFile, "logfile", options.logFile, "Log file name (still always logs to stdout). Cannot be used together with -no-restart/STNORESTART environment variable.")
+	flag.StringVar(&options.logFile, "logfile", options.logFile, "Log file name (still always logs to stdout).")
 	flag.IntVar(&options.logMaxSize, "log-max-size", options.logMaxSize, "Maximum size of any file (zero to disable log rotation).")
 	flag.IntVar(&options.logMaxFiles, "log-max-old-files", options.logMaxFiles, "Number of old files to keep (zero to keep only current).")
 	flag.StringVar(&options.auditFile, "auditfile", options.auditFile, "Specify audit file (use \"-\" for stdout, \"--\" for stderr)")
@@ -260,15 +261,6 @@ func main() {
 		os.Setenv("STGUIAPIKEY", options.guiAPIKey)
 	}
 
-	// Check for options which are not compatible with each other. We have
-	// to check logfile before it's set to the default below - we only want
-	// to complain if they set -logfile explicitly, not if it's set to its
-	// default location
-	if options.noRestart && (options.logFile != "" && options.logFile != "-") {
-		l.Warnln("-logfile may not be used with -no-restart or STNORESTART")
-		os.Exit(syncthing.ExitError.AsInt())
-	}
-
 	if options.hideConsole {
 		osutil.HideConsole()
 	}
@@ -381,7 +373,7 @@ func main() {
 		return
 	}
 
-	if innerProcess || options.noRestart {
+	if innerProcess {
 		syncthingMain(options)
 	} else {
 		monitorMain(options)
@@ -677,7 +669,6 @@ func setupSignalHandling(app *syncthing.App) {
 	// Exit with "success" code (no restart) on INT/TERM
 
 	stopSign := make(chan os.Signal, 1)
-	sigTerm := syscall.Signal(15)
 	signal.Notify(stopSign, os.Interrupt, sigTerm)
 	go func() {
 		<-stopSign

cmd/syncthing/monitor.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -50,6 +51,9 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 
 	logFile := runtimeOptions.logFile
 	if logFile != "-" {
+		if expanded, err := fs.ExpandTilde(logFile); err == nil {
+			logFile = expanded
+		}
 		var fileDst io.Writer
 		if runtimeOptions.logMaxSize > 0 {
 			open := func(name string) (io.WriteCloser, error) {
@@ -79,7 +83,6 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 	var restarts [countRestarts]time.Time
 
 	stopSign := make(chan os.Signal, 1)
-	sigTerm := syscall.Signal(15)
 	signal.Notify(stopSign, os.Interrupt, sigTerm)
 	restartSign := make(chan os.Signal, 1)
 	sigHup := syscall.Signal(1)
@@ -111,7 +114,7 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 			panic(err)
 		}
 
-		l.Infoln("Starting syncthing")
+		l.Debugln("Starting syncthing")
 		err = cmd.Start()
 		if err != nil {
 			l.Warnln("Error starting the main Syncthing process:", err)
@@ -144,12 +147,13 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 			exit <- cmd.Wait()
 		}()
 
+		stopped := false
 		select {
 		case s := <-stopSign:
 			l.Infof("Signal %d received; exiting", s)
 			cmd.Process.Signal(sigTerm)
-			<-exit
-			return
+			err = <-exit
+			stopped = true
 
 		case s := <-restartSign:
 			l.Infof("Signal %d received; restarting", s)
@@ -157,20 +161,31 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 			err = <-exit
 
 		case err = <-exit:
-			if err == nil {
-				// Successful exit indicates an intentional shutdown
-				return
-			} else if exiterr, ok := err.(*exec.ExitError); ok {
-				if exiterr.ExitCode() == syncthing.ExitUpgrade.AsInt() {
-					// Restart the monitor process to release the .old
-					// binary as part of the upgrade process.
-					l.Infoln("Restarting monitor...")
-					if err = restartMonitor(args); err != nil {
-						l.Warnln("Restart:", err)
-					}
-					return
-				}
+		}
+
+		if err == nil {
+			// Successful exit indicates an intentional shutdown
+			os.Exit(syncthing.ExitSuccess.AsInt())
+		}
+
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			exitCode := exiterr.ExitCode()
+			if stopped || runtimeOptions.noRestart {
+				os.Exit(exitCode)
 			}
+			if exitCode == syncthing.ExitUpgrade.AsInt() {
+				// Restart the monitor process to release the .old
+				// binary as part of the upgrade process.
+				l.Infoln("Restarting monitor...")
+				if err = restartMonitor(args); err != nil {
+					l.Warnln("Restart:", err)
+				}
+				os.Exit(exitCode)
+			}
+		}
+
+		if runtimeOptions.noRestart {
+			os.Exit(syncthing.ExitError.AsInt())
 		}
 
 		l.Infoln("Syncthing exited:", err)

etc/linux-desktop/syncthing-start.desktop

@@ -2,7 +2,7 @@
 Name=Start Syncthing
 GenericName=File synchronization
 Comment=Starts the main syncthing process in the background.
-Exec=/usr/bin/syncthing -no-browser
+Exec=/usr/bin/syncthing -no-browser -logfile=~/.config/syncthing/syncthing.log
 Icon=syncthing
 Terminal=false
 Type=Application