// Copyright (c) Tailscale Inc & contributors

// SPDX-License-Identifier: BSD-3-Clause

//go:build linux && !android && !ts_omit_dbus

package dns

import (

"context"

"time"

"github.com/godbus/dbus/v5"

)

func init() {

optDBusPing.Set(dbusPing)

optDBusReadString.Set(dbusReadString)

}

func dbusPing(name, objectPath string) error {

conn, err := dbus.SystemBus()

if err != nil {

// DBus probably not running.

return err

}

ctx, cancel := context.WithTimeout(context.Background(), time.Second)

defer cancel()

obj := conn.Object(name, dbus.ObjectPath(objectPath))

call := obj.CallWithContext(ctx, "org.freedesktop.DBus.Peer.Ping", 0)

return call.Err

}

// dbusReadString reads a string property from the provided name and object

// path. property must be in "interface.member" notation.

func dbusReadString(name, objectPath, iface, member string) (string, error) {

conn, err := dbus.SystemBus()

if err != nil {

// DBus probably not running.

return "", err

}

ctx, cancel := context.WithTimeout(context.Background(), time.Second)

defer cancel()

obj := conn.Object(name, dbus.ObjectPath(objectPath))

var result dbus.Variant

err = obj.CallWithContext(ctx, "org.freedesktop.DBus.Properties.Get", 0, iface, member).Store(&result)

if err != nil {

return "", err

}

if s, ok := result.Value().(string); ok {

return s, nil

}

return result.String(), nil

}