com.cloudera.hadoop.hdfs.nfs.nfs4.UserIDMapper.java Source code

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Here is the source code for com.cloudera.hadoop.hdfs.nfs.nfs4.UserIDMapper.java

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/**
 * Copyright 2011 The Apache Software Foundation
 *
 * 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.cloudera.hadoop.hdfs.nfs.nfs4;

import static com.cloudera.hadoop.hdfs.nfs.nfs4.Constants.*;

import java.util.HashMap;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.ReflectionUtils;
import org.apache.hadoop.util.Shell;

/**
 * Implementing classes need to map RPC UID's to String usernames
 * and String usernames to UIDs. Same for group information.
 */
public abstract class UserIDMapper {

    public abstract int getGIDForGroup(String user, int defaultGID) throws Exception;

    public abstract int getUIDForUser(String user, int defaultUID) throws Exception;

    public abstract String getGroupForGID(int gid, String defaultGroup) throws Exception;

    public abstract String getUserForUID(int gid, String defaultUser) throws Exception;

    protected static Map<Class<?>, UserIDMapper> classUserIdMapperMap = new HashMap<Class<?>, UserIDMapper>();

    public static synchronized UserIDMapper get(Configuration conf) {
        boolean cache = conf.getBoolean(USER_ID_MAPPER_CACHE, true);
        Class<?> clazz = conf.getClass(USER_ID_MAPPER_CLASS, UserIDMapperSystem.class, UserIDMapper.class);
        if (cache) {
            UserIDMapper mapper = classUserIdMapperMap.get(clazz);
            if (mapper == null) {
                mapper = (UserIDMapper) ReflectionUtils.newInstance(clazz, conf);
                classUserIdMapperMap.put(clazz, mapper);
            }
            return mapper;
        }
        return (UserIDMapper) ReflectionUtils.newInstance(clazz, conf);
    }

    /**
     * @return String username associated with the current process
     */
    public static String getCurrentUser() {
        String user = System.getenv("USER");
        if (user != null) {
            try {
                user = Shell.execCommand("whoami").trim();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
        return user;
    }
}