org.apache.hadoop.security.JniBasedUnixGroupsNetgroupMapping 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.Arrays;
import java.util.List;
import java.util.LinkedList;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.util.NativeCodeLoader;
import org.apache.hadoop.security.NetgroupCache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A JNI-based implementation of {@link GroupMappingServiceProvider}
* that invokes libC calls to get the group
* memberships of a given user.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class JniBasedUnixGroupsNetgroupMapping
extends JniBasedUnixGroupsMapping {
private static final Logger LOG = LoggerFactory.getLogger(
JniBasedUnixGroupsNetgroupMapping.class);
native String[] getUsersForNetgroupJNI(String group);
static {
if (!NativeCodeLoader.isNativeCodeLoaded()) {
throw new RuntimeException("Bailing out since native library couldn't " +
"be loaded");
}
LOG.debug("Using JniBasedUnixGroupsNetgroupMapping for Netgroup resolution");
}
/**
* Gets unix groups and netgroups for the user.
*
* It gets all unix groups as returned by id -Gn but it
* only returns netgroups that are used in ACLs (there is
* no way to get all netgroups for a given user, see
* documentation for getent netgroup)
*/
@Override
public List getGroups(String user) throws IOException {
// parent gets unix groups
List groups = new LinkedList(super.getGroups(user));
NetgroupCache.getNetgroups(user, groups);
return groups;
}
/**
* Refresh the netgroup cache
*/
@Override
public void cacheGroupsRefresh() throws IOException {
List groups = NetgroupCache.getNetgroupNames();
NetgroupCache.clear();
cacheGroupsAdd(groups);
}
/**
* Add a group to cache, only netgroups are cached
*
* @param groups list of group names to add to cache
*/
@Override
public void cacheGroupsAdd(List groups) throws IOException {
for(String group: groups) {
if(group.length() == 0) {
// better safe than sorry (should never happen)
} else if(group.charAt(0) == '@') {
if(!NetgroupCache.isCached(group)) {
NetgroupCache.add(group, getUsersForNetgroup(group));
}
} else {
// unix group, not caching
}
}
}
/**
* Calls JNI function to get users for a netgroup, since C functions
* are not reentrant we need to make this synchronized (see
* documentation for setnetgrent, getnetgrent and endnetgrent)
*
* @param netgroup return users for this netgroup
* @return list of users for a given netgroup
*/
protected synchronized List getUsersForNetgroup(String netgroup) {
String[] users = null;
try {
// JNI code does not expect '@' at the beginning of the group name
users = getUsersForNetgroupJNI(netgroup.substring(1));
} catch (Exception e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Error getting users for netgroup " + netgroup, e);
} else {
LOG.info("Error getting users for netgroup " + netgroup +
": " + e.getMessage());
}
}
if (users != null && users.length != 0) {
return Arrays.asList(users);
}
return new LinkedList();
}
}