com.streamsets.datacollector.security.HadoopSecurityUtil.java Source code

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Here is the source code for com.streamsets.datacollector.security.HadoopSecurityUtil.java

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/**
 * 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 java.io.IOException;
import java.security.AccessControlContext;
import java.security.AccessController;

import javax.security.auth.Subject;

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

public class HadoopSecurityUtil {

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

    public static UserGroupInformation getLoginUser(Configuration hdfsConfiguration) throws IOException {
        UserGroupInformation loginUgi;
        AccessControlContext accessContext = AccessController.getContext();
        Subject subject = Subject.getSubject(accessContext);
        // As per SDC-2917 doing this avoids deadlock
        synchronized (SecurityUtil.getSubjectDomainLock(accessContext)) {
            // call some method to force load static block in KerberosName
            KerberosName.hasRulesBeenSet();
        }
        // This should be always out of sync block
        UserGroupInformation.setConfiguration(hdfsConfiguration);
        synchronized (SecurityUtil.getSubjectDomainLock(accessContext)) {
            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;
    }

    public static String getDefaultRealm() throws ReflectiveOperationException {
        AccessControlContext accessContext = AccessController.getContext();
        synchronized (SecurityUtil.getSubjectDomainLock(accessContext)) {
            return KerberosUtil.getDefaultRealm();
        }
    }

    public static UserGroupInformation getProxyUser(String user, UserGroupInformation loginUser) {
        AccessControlContext accessContext = AccessController.getContext();
        synchronized (SecurityUtil.getSubjectDomainLock(accessContext)) {
            return UserGroupInformation.createProxyUser(user, loginUser);
        }
    }

}