| /** |
| * 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.hadoop.security; |
| |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * Class that caches the netgroups and inverts group-to-user map |
| * to user-to-group map, primarily intended for use with |
| * netgroups (as returned by getent netgrgoup) which only returns |
| * group to user mapping. |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"}) |
| @InterfaceStability.Unstable |
| public class NetgroupCache { |
| private static ConcurrentHashMap<String, Set<String>> userToNetgroupsMap = |
| new ConcurrentHashMap<String, Set<String>>(); |
| |
| /** |
| * Get netgroups for a given user |
| * |
| * @param user get groups for this user |
| * @param groups put groups into this List |
| */ |
| public static void getNetgroups(final String user, |
| List<String> groups) { |
| Set<String> userGroups = userToNetgroupsMap.get(user); |
| //ConcurrentHashMap does not allow null values; |
| //So null value check can be used to check if the key exists |
| if (userGroups != null) { |
| groups.addAll(userGroups); |
| } |
| } |
| |
| /** |
| * Get the list of cached netgroups |
| * |
| * @return list of cached groups |
| */ |
| public static List<String> getNetgroupNames() { |
| return new LinkedList<String>(getGroups()); |
| } |
| |
| private static Set<String> getGroups() { |
| Set<String> allGroups = new HashSet<String> (); |
| for (Set<String> userGroups : userToNetgroupsMap.values()) { |
| allGroups.addAll(userGroups); |
| } |
| return allGroups; |
| } |
| |
| /** |
| * Returns true if a given netgroup is cached |
| * |
| * @param group check if this group is cached |
| * @return true if group is cached, false otherwise |
| */ |
| public static boolean isCached(String group) { |
| return getGroups().contains(group); |
| } |
| |
| /** |
| * Clear the cache |
| */ |
| public static void clear() { |
| userToNetgroupsMap.clear(); |
| } |
| |
| /** |
| * Add group to cache |
| * |
| * @param group name of the group to add to cache |
| * @param users list of users for a given group |
| */ |
| public static void add(String group, List<String> users) { |
| for (String user : users) { |
| Set<String> userGroups = userToNetgroupsMap.get(user); |
| // ConcurrentHashMap does not allow null values; |
| // So null value check can be used to check if the key exists |
| if (userGroups == null) { |
| //Generate a ConcurrentHashSet (backed by the keyset of the ConcurrentHashMap) |
| userGroups = |
| Collections.newSetFromMap(new ConcurrentHashMap<String,Boolean>()); |
| Set<String> currentSet = userToNetgroupsMap.putIfAbsent(user, userGroups); |
| if (currentSet != null) { |
| userGroups = currentSet; |
| } |
| } |
| userGroups.add(group); |
| } |
| } |
| } |