org.apache.hadoop.security.ShellBasedUnixGroupsMapping Maven / Gradle / Ivy
/**
* 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.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.util.Shell;
import org.apache.hadoop.util.Shell.ExitCodeException;
/**
* A simple shell-based implementation of {@link GroupMappingServiceProvider}
* that exec's the groups shell command to fetch the group
* memberships of a given user.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class ShellBasedUnixGroupsMapping
implements GroupMappingServiceProvider {
private static final Log LOG =
LogFactory.getLog(ShellBasedUnixGroupsMapping.class);
/**
* Returns list of groups for a user
*
* @param user get groups for this user
* @return list of groups for a given user
*/
@Override
public List getGroups(String user) throws IOException {
return getUnixGroups(user);
}
/**
* Caches groups, no need to do that for this provider
*/
@Override
public void cacheGroupsRefresh() throws IOException {
// does nothing in this provider of user to groups mapping
}
/**
* Adds groups to cache, no need to do that for this provider
*
* @param groups unused
*/
@Override
public void cacheGroupsAdd(List groups) throws IOException {
// does nothing in this provider of user to groups mapping
}
/**
* Get the current user's group list from Unix by running the command 'groups'
* NOTE. For non-existing user it will return EMPTY list
* @param user user name
* @return the groups list that the user belongs to
* @throws IOException if encounter any error when running the command
*/
private static List getUnixGroups(final String user) throws IOException {
String result = "";
try {
result = Shell.execCommand(Shell.getGroupsForUserCommand(user));
} catch (ExitCodeException e) {
// if we didn't get the group - just return empty list;
LOG.warn("got exception trying to get groups for user " + user, e);
}
StringTokenizer tokenizer = new StringTokenizer(result);
List groups = new LinkedList();
while (tokenizer.hasMoreTokens()) {
groups.add(tokenizer.nextToken());
}
return groups;
}
}