001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.util;
018
019import java.net.InetAddress;
020import java.net.NetworkInterface;
021import java.net.SocketException;
022import java.net.UnknownHostException;
023import java.util.Enumeration;
024
025import org.apache.logging.log4j.Logger;
026import org.apache.logging.log4j.status.StatusLogger;
027
028/**
029 *
030 */
031public final class NetUtils {
032
033    private static final Logger LOGGER = StatusLogger.getLogger();
034
035    private NetUtils() {
036    }
037
038    /**
039     * This method gets the network name of the machine we are running on.
040     * Returns "UNKNOWN_LOCALHOST" in the unlikely case where the host name
041     * cannot be found.
042     *
043     * @return String the name of the local host
044     */
045    public static String getLocalHostname() {
046        try {
047            final InetAddress addr = InetAddress.getLocalHost();
048            return addr.getHostName();
049        } catch (final UnknownHostException uhe) {
050            try {
051                final Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
052                while (interfaces.hasMoreElements()) {
053                    final NetworkInterface nic = interfaces.nextElement();
054                    final Enumeration<InetAddress> addresses = nic.getInetAddresses();
055                    while (addresses.hasMoreElements()) {
056                        final InetAddress address = addresses.nextElement();
057                        if (!address.isLoopbackAddress()) {
058                            final String hostname = address.getHostName();
059                            if (hostname != null) {
060                                return hostname;
061                            }
062                        }
063                    }
064                }
065            } catch (final SocketException se) {
066                LOGGER.error("Could not determine local host name", uhe);
067                return "UNKNOWN_LOCALHOST";
068            }
069            LOGGER.error("Could not determine local host name", uhe);
070            return "UNKNOWN_LOCALHOST";
071        }
072    }
073
074}