DefaultLoginUgiProvider.java

/**
 * Copyright 2016 StreamSets Inc.
 *
 * Licensed under 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.streamsets.datacollector.security;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.authentication.util.KerberosName;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.security.auth.Subject;
import java.io.IOException;
import java.security.AccessControlContext;
import java.security.AccessController;

public class DefaultLoginUgiProvider extends LoginUgiProvider {

  private static final Logger LOG = LoggerFactory.getLogger(DefaultLoginUgiProvider.class);

  @Override
  public UserGroupInformation getLoginUgi(Configuration hdfsConfiguration) throws IOException {
    AccessControlContext accessContext = AccessController.getContext();
    Subject subject = Subject.getSubject(accessContext);
    // As per SDC-2917 doing this avoids deadlock
    UserGroupInformation loginUgi;
    synchronized (SecurityUtil.getSubjectDomainLock(accessContext)) {
      // call some method to force load static block in KerberosName
      KerberosName.hasRulesBeenSet();
      UserGroupInformation.setConfiguration(hdfsConfiguration);
      if (UserGroupInformation.isSecurityEnabled()) {
        loginUgi = UserGroupInformation.getUGIFromSubject(subject);
      } else {
        UserGroupInformation.loginUserFromSubject(subject);
        loginUgi = UserGroupInformation.getLoginUser();
      }
      if (LOG.isDebugEnabled()) {
        LOG.debug(
            "Subject = {}, Principals = {}, Login UGI = {}",
            subject,
            subject == null ? "null" : subject.getPrincipals(),
            loginUgi
        );
      }
    }
    return loginUgi;
  }
}