content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.jstorm.hdfs.common.security;
  
  
  import backtype.storm.security.auth.kerberos.AutoTGT;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.security.SecurityUtil;
  import org.apache.hadoop.security.UserGroupInformation;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import static backtype.storm.Config.TOPOLOGY_AUTO_CREDENTIALS;
  
  /**
   * This class provides util methods for storm-hdfs connector communicating
   * with secured HDFS.
   */
  public class HdfsSecurityUtil {
      public static final String STORM_KEYTAB_FILE_KEY = "hdfs.keytab.file";
      public static final String STORM_USER_NAME_KEY = "hdfs.kerberos.principal";
  
      private static final Logger LOG = LoggerFactory.getLogger(HdfsSecurityUtil.class);
      private static AtomicBoolean isLoggedIn = new AtomicBoolean();
      public static void login(Map conf, Configuration hdfsConfig) throws IOException {
          //If AutoHDFS is specified, do not attempt to login using keytabs, only kept for backward compatibility.
          if(conf.get(TOPOLOGY_AUTO_CREDENTIALS) == null ||
                  (!(((List)conf.get(TOPOLOGY_AUTO_CREDENTIALS)).contains(AutoHDFS.class.getName())) &&
                   !(((List)conf.get(TOPOLOGY_AUTO_CREDENTIALS)).contains(AutoTGT.class.getName())))) {
              if (UserGroupInformation.isSecurityEnabled()) {
                  // compareAndSet added because of https://issues.apache.org/jira/browse/STORM-1535
                  if (isLoggedIn.compareAndSet(false, true)) {
                      LOG.info("Logging in using keytab as AutoHDFS is not specified for " + TOPOLOGY_AUTO_CREDENTIALS);
                      String keytab = (String) conf.get(STORM_KEYTAB_FILE_KEY);
                      if (keytab != null) {
                          hdfsConfig.set(STORM_KEYTAB_FILE_KEY, keytab);
                      }
                      String userName = (String) conf.get(STORM_USER_NAME_KEY);
                      if (userName != null) {
                          hdfsConfig.set(STORM_USER_NAME_KEY, userName);
                      }
                      SecurityUtil.login(hdfsConfig, STORM_KEYTAB_FILE_KEY, STORM_USER_NAME_KEY);
                  }
              }
          }
      }
  }
  