/**
* 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.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableFactories;
import org.apache.hadoop.io.WritableFactory;
/**
* A class for file/directory permissions.
*/
public class FsPermission implements Writable {
private static final Log LOG = LogFactory.getLog(FsPermission.class);
static final WritableFactory FACTORY = new WritableFactory() {
public Writable newInstance() { return new FsPermission(); }
};
static { // register a ctor
WritableFactories.setFactory(FsPermission.class, FACTORY);
WritableFactories.setFactory(ImmutableFsPermission.class, FACTORY);
}
/** Create an immutable {@link FsPermission} object. */
public static FsPermission createImmutable(short permission) {
return new ImmutableFsPermission(permission);
}
//POSIX permission style
private FsAction useraction = null;
private FsAction groupaction = null;
private FsAction otheraction = null;
private FsPermission() {}
/**
* Construct by the given {@link FsAction}.
* @param u user action
* @param g group action
* @param o other action
*/
public FsPermission(FsAction u, FsAction g, FsAction o) {set(u, g, o);}
/**
* Construct by the given mode.
* @param mode
* @see #toShort()
*/
public FsPermission(short mode) { fromShort(mode); }
/**
* Copy constructor
*
* @param other other permission
*/
public FsPermission(FsPermission other) {
this.useraction = other.useraction;
this.groupaction = other.groupaction;
this.otheraction = other.otheraction;
}
/**
* Construct by given mode, either in octal or symbolic format.
* @param mode mode as a string, either in octal or symbolic format
* @throws IllegalArgumentException if <code>mode</code> is invalid
*/
public FsPermission(String mode) {
this(new UmaskParser(mode).getUMask());
}
/** Return user {@link FsAction}. */
public FsAction getUserAction() {return useraction;}
/** Return group {@link FsAction}. */
public FsAction getGroupAction() {return groupaction;}
/** Return other {@link FsAction}. */
public FsAction getOtherAction() {return otheraction;}
private void set(FsAction u, FsAction g, FsAction o) {
useraction = u;
groupaction = g;
otheraction = o;
}
public void fromShort(short n) {
FsAction[] v = FsAction.values();
set(v[(n >>> 6) & 7], v[(n >>> 3) & 7], v[n & 7]);
}
/** {@inheritDoc} */
public void write(DataOutput out) throws IOException {
out.writeShort(toShort());
}
/** {@inheritDoc} */
public void readFields(DataInput in) throws IOException {
fromShort(in.readShort());
}
/**
* Create and initialize a {@link FsPermission} from {@link DataInput}.
*/
public static FsPermission read(DataInput in) throws IOException {
FsPermission p = new FsPermission();
p.readFields(in);
return p;
}
/**
* Encode the object to a short.
*/
public short toShort() {
int s = (useraction.ordinal() << 6) | (groupaction.ordinal() << 3) |
otheraction.ordinal();
return (short)s;
}
/** {@inheritDoc} */
public boolean equals(Object obj) {
if (obj instanceof FsPermission) {
FsPermission that = (FsPermission)obj;
return this.useraction == that.useraction
&& this.groupaction == that.groupaction
&& this.otheraction == that.otheraction;
}
return false;
}
/** {@inheritDoc} */
public int hashCode() {return toShort();}
/** {@inheritDoc} */
public String toString() {
return useraction.SYMBOL + groupaction.SYMBOL + otheraction.SYMBOL;
}
/** Apply a umask to this permission and return a new one */
public FsPermission applyUMask(FsPermission umask) {
return new FsPermission(useraction.and(umask.useraction.not()),
groupaction.and(umask.groupaction.not()),
otheraction.and(umask.otheraction.not()));
}
/** umask property label */
public static final String DEPRECATED_UMASK_LABEL = "dfs.umask";
public static final String UMASK_LABEL = "dfs.umaskmode";
public static final int DEFAULT_UMASK = 0022;
/**
* Get the user file creation mask (umask)
*
* {@code UMASK_LABEL} config param has umask value that is either symbolic
* or octal.
*
* Symbolic umask is applied relative to file mode creation mask;
* the permission op characters '+' clears the corresponding bit in the mask,
* '-' sets bits in the mask.
*
* Octal umask, the specified bits are set in the file mode creation mask.
*
* {@code DEPRECATED_UMASK_LABEL} config param has umask value set to decimal.
*/
public static FsPermission getUMask(Configuration conf) {
int umask = DEFAULT_UMASK;
// To ensure backward compatibility first use the deprecated key.
// If the deprecated key is not present then check for the new key
if(conf != null) {
int oldStyleValue = conf.getInt(DEPRECATED_UMASK_LABEL, Integer.MIN_VALUE);
if(oldStyleValue != Integer.MIN_VALUE) { // Property was set with old key
LOG.warn(DEPRECATED_UMASK_LABEL + " configuration key is deprecated. " +
"Convert to " + UMASK_LABEL + ", using octal or symbolic umask " +
"specifications.");
umask = oldStyleValue;
} else {
String confUmask = conf.get(UMASK_LABEL);
if(confUmask != null) { // UMASK_LABEL is set
return new FsPermission(confUmask);
}
}
}
return new FsPermission((short)umask);
}
/** Set the user file creation mask (umask) */
public static void setUMask(Configuration conf, FsPermission umask) {
conf.set(UMASK_LABEL, String.format("%1$03o", umask.toShort()));
}
/** Get the default permission. */
public static FsPermission getDefault() {
return new FsPermission((short)0777);
}
/**
* Create a FsPermission from a Unix symbolic permission string
* @param unixSymbolicPermission e.g. "-rw-rw-rw-"
*/
public static FsPermission valueOf(String unixSymbolicPermission) {
if (unixSymbolicPermission == null) {
return null;
}
else if (unixSymbolicPermission.length() != 10) {
throw new IllegalArgumentException("length != 10(unixSymbolicPermission="
+ unixSymbolicPermission + ")");
}
int n = 0;
for(int i = 1; i < unixSymbolicPermission.length(); i++) {
n = n << 1;
char c = unixSymbolicPermission.charAt(i);
n += (c == '-' || c == 'T' || c == 'S') ? 0: 1;
}
return new FsPermission((short)n);
}
private static class ImmutableFsPermission extends FsPermission {
public ImmutableFsPermission(short permission) {
super(permission);
}
public FsPermission applyUMask(FsPermission umask) {
throw new UnsupportedOperationException();
}
public void readFields(DataInput in) throws IOException {
throw new UnsupportedOperationException();
}
}
}