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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.core.util;
    18
    19  import java.net.InetAddress;
    20  import java.net.NetworkInterface;
    21  import java.net.SocketException;
    22  import java.net.UnknownHostException;
    23  import java.util.Enumeration;
    24
    25  import org.apache.logging.log4j.Logger;
    26  import org.apache.logging.log4j.status.StatusLogger;
    27
    28  /**
    29   *
    30   */
    31  public final class NetUtils {
    32
    33      private static final Logger LOGGER = StatusLogger.getLogger();
    34
    35      private NetUtils() {
    36      }
    37
    38      /**
    39       * This method gets the network name of the machine we are running on.
    40       * Returns "UNKNOWN_LOCALHOST" in the unlikely case where the host name
    41       * cannot be found.
    42       *
    43       * @return String the name of the local host
    44       */
    45      public static String getLocalHostname() {
    46          try {
    47              final InetAddress addr = InetAddress.getLocalHost();
    48              return addr.getHostName();
    49          } catch (final UnknownHostException uhe) {
    50              try {
    51                  final Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
    52                  while (interfaces.hasMoreElements()) {
    53                      final NetworkInterface nic = interfaces.nextElement();
    54                      final Enumeration<InetAddress> addresses = nic.getInetAddresses();
    55                      while (addresses.hasMoreElements()) {
    56                          final InetAddress address = addresses.nextElement();
    57                          if (!address.isLoopbackAddress()) {
    58                              final String hostname = address.getHostName();
    59                              if (hostname != null) {
    60                                  return hostname;
    61                              }
    62                          }
    63                      }
    64                  }
    65              } catch (final SocketException se) {
    66                  LOGGER.error("Could not determine local host name", uhe);
    67                  return "UNKNOWN_LOCALHOST";
    68              }
    69              LOGGER.error("Could not determine local host name", uhe);
    70              return "UNKNOWN_LOCALHOST";
    71          }
    72      }
    73
    74  }