add web port check on start

server/server.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"io/ioutil"
+	"net"
 	"os"
 	"path/filepath"
 
@@ -15,9 +16,19 @@ func Start(port string, roSets bool) {
 	if port == "" {
 		port = "8090"
 	}
+	log.TLogln("Check web port", port)
+	l, err := net.Listen("tcp", ":"+port)
+	if l != nil {
+		l.Close()
+	}
+	if err != nil {
+		log.TLogln("Port", port, "already in use! Abort")
+		os.Exit(1)
+	} else {
 	  go cleanCache()
 	  web.Start(port)
 	}
+}
 
 func cleanCache() {
 	if !settings.BTsets.UseDisk || settings.BTsets.TorrentsSavePath == "/" || settings.BTsets.TorrentsSavePath == "" {