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/**
* 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.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* Base class for parsing either chmod permissions or umask permissions.
* Includes common code needed by either operation as implemented in
* UmaskParser and ChmodParser classes.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
class PermissionParser {
protected boolean symbolic = false;
protected short userMode;
protected short groupMode;
protected short othersMode;
protected short stickyMode;
protected char userType = '+';
protected char groupType = '+';
protected char othersType = '+';
protected char stickyBitType = '+';
/**
* Begin parsing permission stored in modeStr
*
* @param modeStr Permission mode, either octal or symbolic
* @param symbolic Use-case specific symbolic pattern to match against
* @throws IllegalArgumentException if unable to parse modeStr
*/
public PermissionParser(String modeStr, Pattern symbolic, Pattern octal)
throws IllegalArgumentException {
Matcher matcher = null;
if ((matcher = symbolic.matcher(modeStr)).find()) {
applyNormalPattern(modeStr, matcher);
} else if ((matcher = octal.matcher(modeStr)).matches()) {
applyOctalPattern(matcher);
} else {
throw new IllegalArgumentException(modeStr);
}
}
private void applyNormalPattern(String modeStr, Matcher matcher) {
// Are there multiple permissions stored in one chmod?
boolean commaSeparated = false;
for (int i = 0; i < 1 || matcher.end() < modeStr.length(); i++) {
if (i > 0 && (!commaSeparated || !matcher.find())) {
throw new IllegalArgumentException(modeStr);
}
/*
* groups : 1 : [ugoa]* 2 : [+-=] 3 : [rwxXt]+ 4 : [,\s]*
*/
String str = matcher.group(2);
char type = str.charAt(str.length() - 1);
boolean user, group, others, stickyBit;
user = group = others = stickyBit = false;
for (char c : matcher.group(1).toCharArray()) {
switch (c) {
case 'u':
user = true;
break;
case 'g':
group = true;
break;
case 'o':
others = true;
break;
case 'a':
break;
default:
throw new RuntimeException("Unexpected");
}
}
if (!(user || group || others)) { // same as specifying 'a'
user = group = others = true;
}
short mode = 0;
for (char c : matcher.group(3).toCharArray()) {
switch (c) {
case 'r':
mode |= 4;
break;
case 'w':
mode |= 2;
break;
case 'x':
mode |= 1;
break;
case 'X':
mode |= 8;
break;
case 't':
stickyBit = true;
break;
default:
throw new RuntimeException("Unexpected");
}
}
if (user) {
userMode = mode;
userType = type;
}
if (group) {
groupMode = mode;
groupType = type;
}
if (others) {
othersMode = mode;
othersType = type;
stickyMode = (short) (stickyBit ? 1 : 0);
stickyBitType = type;
}
commaSeparated = matcher.group(4).contains(",");
}
symbolic = true;
}
private void applyOctalPattern(final Matcher matcher) {
// Matcher groups: 1: [01] 2: [0-7]{3}
final char typeApply = '=';
stickyBitType = typeApply;
userType = typeApply;
groupType = typeApply;
othersType = typeApply;
// If sticky bit is specified get the bit, else
// default to reset for apply condition
String sb = matcher.group(1);
if (!sb.isEmpty()) {
stickyMode = Short.valueOf(sb.substring(0, 1));
} else {
stickyMode = 0;
}
String str = matcher.group(2);
userMode = Short.valueOf(str.substring(0, 1));
groupMode = Short.valueOf(str.substring(1, 2));
othersMode = Short.valueOf(str.substring(2, 3));
}
protected int combineModes(int existing, boolean exeOk) {
return combineModeSegments(stickyBitType, stickyMode,
(existing>>>9), false) << 9 |
combineModeSegments(userType, userMode,
(existing>>>6)&7, exeOk) << 6 |
combineModeSegments(groupType, groupMode,
(existing>>>3)&7, exeOk) << 3 |
combineModeSegments(othersType, othersMode, existing&7, exeOk);
}
protected int combineModeSegments(char type, int mode,
int existing, boolean exeOk) {
boolean capX = false;
if ((mode&8) != 0) { // convert X to x;
capX = true;
mode &= ~8;
mode |= 1;
}
switch (type) {
case '+' : mode = mode | existing; break;
case '-' : mode = (~mode) & existing; break;
case '=' : break;
default : throw new RuntimeException("Unexpected");
}
// if X is specified add 'x' only if exeOk or x was already set.
if (capX && !exeOk && (mode&1) != 0 && (existing&1) == 0) {
mode &= ~1; // remove x
}
return mode;
}
}