server: now change effective user/group if current user == 0

app/server/server.go

@@ -150,43 +150,59 @@ func (srv *Server) Build() error {
 	var err error
 	//srv.logg.Infof("Server building")
 
-	usr, err := user.Lookup(srv.conf.RunUser)
+	currUser, err := user.Current()
+	if err != nil {
+		err = fmt.Errorf("Error getting current user: %v\n", err)
+		return err
+	}
+	cuid64, err := strconv.ParseInt(currUser.Uid, 10, 64)
 	if err != nil {
 		return err
 	}
-	uid64, err := strconv.ParseInt(usr.Uid, 10, 64)
+	cgid64, err := strconv.ParseInt(currUser.Gid, 10, 64)
 	if err != nil {
 		return err
 	}
-	gid64, err := strconv.ParseInt(usr.Gid, 10, 64)
-	if err != nil {
-		return err
+	euid := int(cuid64)
+	egid := int(cgid64)
+	if cuid64 == 0 {
+		usr, err := user.Lookup(srv.conf.RunUser)
+		if err != nil {
+			return err
+		}
+		uid64, err := strconv.ParseInt(usr.Uid, 10, 64)
+		if err != nil {
+			return err
+		}
+		gid64, err := strconv.ParseInt(usr.Gid, 10, 64)
+		if err != nil {
+			return err
+		}
+		euid = int(uid64)
+		egid = int(gid64)
 	}
-	uid := int(uid64)
-	gid := int(gid64)
-
 	// Creating datadir
 	datadir := srv.conf.Datadir
 	if !auxtool.DirExists(datadir) { // TODO: check access to dir
-		srv.logg.Infof("Creating data directory %s ", datadir)
+		//srv.logg.Infof("Creating data directory %s ", datadir)
 		err = os.MkdirAll(datadir, 0750)
 		if err != nil {
 			return err
 		}
 	}
-	err = os.Chown(datadir, uid, gid)
+	err = os.Chown(datadir, euid, egid)
 	if err != nil {
 		return err
 	}
 
 	if srv.conf.AsDaemon {
 		logdir := filepath.Dir(srv.conf.Logpath)
-		srv.logg.Infof("Creating log directory %s", logdir)
+		//srv.logg.Infof("Creating log directory %s", logdir)
 		err = os.MkdirAll(logdir, 0750)
 		if err != nil {
 			return err
 		}
-		err = os.Chown(logdir, uid, gid)
+		err = os.Chown(logdir, euid, egid)
 		if err != nil {
 			return err
 		}
@@ -196,7 +212,7 @@ func (srv *Server) Build() error {
 		if err != nil {
 			return err
 		}
-		err = os.Chown(rundir, uid, gid)
+		err = os.Chown(rundir, euid, egid)
 		if err != nil {
 			return err
 		}
@@ -239,7 +255,7 @@ func (srv *Server) Build() error {
 	if err != nil {
 		return err
 	}
-	err = os.Chown(datadir, uid, gid)
+	err = os.Chown(datadir, euid, egid)
 	if err != nil {
 		return err
 	}
@@ -252,22 +268,24 @@ func (srv *Server) Build() error {
 	}
 	srv.listen = listener
 
-	// Change effective user amd group
-	err = syscall.Setuid(uid)
-	if err != nil {
-		return err
-	}
-	err = syscall.Setgid(gid)
-	if err != nil {
-		return err
+	if cuid64 == 0 {
+		// Change effective user and group
+		err = syscall.Setuid(euid)
+		if err != nil {
+			return err
+		}
+		err = syscall.Setgid(egid)
+		if err != nil {
+			return err
+		}
 	}
+
 	uidstr := strconv.FormatInt(int64(syscall.Geteuid()), 10)
-	usr, err = user.LookupId(uidstr)
+	usr, err := user.LookupId(uidstr)
 	if err != nil {
 		return err
 	}
 	srv.logg.Warningf("Now run as user: %s", usr.Username)
-
 	// Creating database
 	mdb := maindb.NewDatabase(dbdir)
 	srv.logg.Infof("Opening main database")