    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     */
    017    package org.apache.logging.log4j.core.util;
    018
    019    import java.net.InetAddress;
    020    import java.net.NetworkInterface;
    021    import java.net.SocketException;
    022    import java.net.UnknownHostException;
    023    import java.util.Enumeration;
    024
    025    import org.apache.logging.log4j.Logger;
    026    import org.apache.logging.log4j.status.StatusLogger;
    027
    028    /**
    029     *
    030     */
    031    public 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    }