org.apache.hadoop.fs.permission.AclUtil 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.fs.permission;
import java.util.Iterator;
import java.util.List;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
/**
* AclUtil contains utility methods for manipulating ACLs.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Unstable
public final class AclUtil {
/**
* Given permissions and extended ACL entries, returns the full logical ACL.
*
* @param perm FsPermission containing permissions
* @param entries List<AclEntry> containing extended ACL entries
* @return List<AclEntry> containing full logical ACL
*/
public static List getAclFromPermAndEntries(FsPermission perm,
List entries) {
List acl = Lists.newArrayListWithCapacity(entries.size() + 3);
// Owner entry implied by owner permission bits.
acl.add(new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(AclEntryType.USER)
.setPermission(perm.getUserAction())
.build());
// All extended access ACL entries.
boolean hasAccessAcl = false;
Iterator entryIter = entries.iterator();
AclEntry curEntry = null;
while (entryIter.hasNext()) {
curEntry = entryIter.next();
if (curEntry.getScope() == AclEntryScope.DEFAULT) {
break;
}
hasAccessAcl = true;
acl.add(curEntry);
}
// Mask entry implied by group permission bits, or group entry if there is
// no access ACL (only default ACL).
acl.add(new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(hasAccessAcl ? AclEntryType.MASK : AclEntryType.GROUP)
.setPermission(perm.getGroupAction())
.build());
// Other entry implied by other bits.
acl.add(new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(AclEntryType.OTHER)
.setPermission(perm.getOtherAction())
.build());
// Default ACL entries.
if (curEntry != null && curEntry.getScope() == AclEntryScope.DEFAULT) {
acl.add(curEntry);
while (entryIter.hasNext()) {
acl.add(entryIter.next());
}
}
return acl;
}
/**
* Translates the given permission bits to the equivalent minimal ACL.
*
* @param perm FsPermission to translate
* @return List<AclEntry> containing exactly 3 entries representing the
* owner, group and other permissions
*/
public static List getMinimalAcl(FsPermission perm) {
return Lists.newArrayList(
new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(AclEntryType.USER)
.setPermission(perm.getUserAction())
.build(),
new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(AclEntryType.GROUP)
.setPermission(perm.getGroupAction())
.build(),
new AclEntry.Builder()
.setScope(AclEntryScope.ACCESS)
.setType(AclEntryType.OTHER)
.setPermission(perm.getOtherAction())
.build());
}
/**
* Checks if the given entries represent a minimal ACL (contains exactly 3
* entries).
*
* @param entries List<AclEntry> entries to check
* @return boolean true if the entries represent a minimal ACL
*/
public static boolean isMinimalAcl(List entries) {
return entries.size() == 3;
}
/**
* There is no reason to instantiate this class.
*/
private AclUtil() {
}
}