Improve Unix domain socket support

main.go

@@ -49,6 +49,7 @@ var repoRoot string
 var printVersion = flag.Bool("version", false, "Print version and exit")
 var listenAddr = flag.String("listenAddr", "localhost:8181", "Listen address for HTTP server")
 var listenNetwork = flag.String("listenNetwork", "tcp", "Listen 'network' (protocol)")
+var listenUmask = flag.Int("listenUmask", 022, "Umask for Unix socket, default: 022")
 var authBackend = flag.String("authBackend", "http://localhost:8080", "Authentication/authorization backend")
 
 var gitServices = [...]gitService{
@@ -77,10 +78,22 @@ func main() {
 	log.Printf("repoRoot: %s", repoRoot)
 
 	http.HandleFunc("/", gitHandler)
+
+	// Good housekeeping for Unix sockets: unlink before binding
+	if *listenNetwork == "unix" {
+		if err := os.Remove(*listenAddr); err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	// Change the umask only around net.Listen()
+	oldUmask := syscall.Umask(*listenUmask)
 	listener, err := net.Listen(*listenNetwork, *listenAddr)
+	syscall.Umask(oldUmask)
 	if err != nil {
 		log.Fatal(err)
 	}
+
 	log.Fatal(http.Serve(listener, nil))
 }