org.apache.jxtadoop.security.SecurityUtil.java Source code

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Here is the source code for org.apache.jxtadoop.security.SecurityUtil.java

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/**
 * 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 org.apache.jxtadoop.security;

import java.security.Policy;
import java.security.Principal;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

import javax.security.auth.Subject;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.jxtadoop.conf.Configuration;
import org.apache.jxtadoop.security.authorize.ConfiguredPolicy;
import org.apache.jxtadoop.security.authorize.PolicyProvider;

public class SecurityUtil {

    private static final Log LOG = LogFactory.getLog(SecurityUtil.class);

    static {
        // Set an empty default policy
        setPolicy(new ConfiguredPolicy(new Configuration(), PolicyProvider.DEFAULT_POLICY_PROVIDER));
    }

    /**
     * Set the global security policy for Hadoop.
     * 
     * @param policy {@link Policy} used for authorization.
     */
    public static void setPolicy(Policy policy) {
        if (LOG.isDebugEnabled()) {
            LOG.debug("Setting Hadoop security policy");
        }
        Policy.setPolicy(policy);
    }

    /**
     * Get the current global security policy for Hadoop.
     * @return the current {@link Policy}
     */
    public static Policy getPolicy() {
        return Policy.getPolicy();
    }

    /**
     * Get the {@link Subject} for the user identified by <code>ugi</code>.
     * @param ugi user
     * @return the {@link Subject} for the user identified by <code>ugi</code>
     */
    public static Subject getSubject(UserGroupInformation ugi) {
        if (ugi == null) {
            return null;
        }

        Set<Principal> principals = // Number of principals = username + #groups 
                new HashSet<Principal>(ugi.getGroupNames().length + 1);
        User userPrincipal = new User(ugi.getUserName());
        principals.add(userPrincipal);
        for (String group : ugi.getGroupNames()) {
            Group groupPrincipal = new Group(group);
            principals.add(groupPrincipal);
        }
        principals.add(ugi);
        Subject user = new Subject(false, principals, new HashSet<Object>(), new HashSet<Object>());

        return user;
    }

    /**
     * Class representing a configured access control list.
     */
    public static class AccessControlList {

        // Indicates an ACL string that represents access to all users
        public static final String WILDCARD_ACL_VALUE = "*";

        // Set of users who are granted access.
        private Set<String> users;
        // Set of groups which are granted access
        private Set<String> groups;
        // Whether all users are granted access.
        private boolean allAllowed;

        /**
         * Construct a new ACL from a String representation of the same.
         * 
         * The String is a a comma separated list of users and groups.
         * The user list comes first and is separated by a space followed 
         * by the group list. For e.g. "user1,user2 group1,group2"
         * 
         * @param aclString String representation of the ACL
         */
        public AccessControlList(String aclString) {
            users = new TreeSet<String>();
            groups = new TreeSet<String>();
            if (aclString.contains(WILDCARD_ACL_VALUE) && aclString.trim().equals(WILDCARD_ACL_VALUE)) {
                allAllowed = true;
            } else {
                String[] userGroupStrings = aclString.split(" ", 2);

                if (userGroupStrings.length >= 1) {
                    String[] usersStr = userGroupStrings[0].split(",");
                    if (usersStr.length >= 1) {
                        addToSet(users, usersStr);
                    }
                }

                if (userGroupStrings.length == 2) {
                    String[] groupsStr = userGroupStrings[1].split(",");
                    if (groupsStr.length >= 1) {
                        addToSet(groups, groupsStr);
                    }
                }
            }
        }

        public boolean allAllowed() {
            return allAllowed;
        }

        public Set<String> getUsers() {
            return users;
        }

        public Set<String> getGroups() {
            return groups;
        }

        private static final void addToSet(Set<String> set, String[] strings) {
            for (String s : strings) {
                s = s.trim();
                if (s.length() > 0) {
                    set.add(s);
                }
            }
        }
    }
}