/*
* 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 java.io;
import java.security.AccessController;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.PrivilegedAction;
import org.apache.harmony.luni.util.Msg;
/**
* A permission for accessing a file or directory. The FilePermission is made up
* of a pathname and a set of actions which are valid for the pathname.
* <p>
* The {@code File.separatorChar} must be used in all pathnames when
* constructing a FilePermission. The following descriptions will assume the
* char is {@code /}. A pathname that ends in {@code /*} includes all the files
* and directories contained in that directory. If the pathname
* ends in {@code /-}, it includes all the files and directories in that
* directory <i>recursively</i>. The following pathnames have a special meaning:
* </p>
* <ul>
* <li>
* "*": all files in the current directory;
* </li>
* <li>
* "-": recursively all files and directories in the current directory;
* </li>
* <li>
* "<<ALL FILES>>": any file and directory in the file system.
* </li>
* </ul>
*
* @since Android 1.0
*/
public final class FilePermission extends Permission implements Serializable {
private static final long serialVersionUID = 7930732926638008763L;
// canonical path of this permission
private transient String canonPath;
// list of actions permitted for socket permission in order
private static final String[] actionList = { "read", "write", "execute", //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
"delete" }; //$NON-NLS-1$
// "canonicalized" action list
private String actions;
// the numeric representation of this action list
// for implies() to check if one action list is the subset of another.
transient int mask = -1;
// global include all permission?
private transient boolean includeAll = false;
private transient boolean allDir = false;
private transient boolean allSubdir = false;
/**
* Constructs a new FilePermission with the path and actions specified.
*
* @param path
* the pathname of the file or directory to apply the actions to.
* @param actions
* the actions for the {@code path}. May be any combination of
* "read", "write", "execute" and "delete".
* @throws IllegalArgumentException
* if {@code actions} is {@code null} or an empty string, or if
* it contains a string other than "read", "write", "execute"
* and "delete".
* @throws NullPointerException
* if {@code path} is null.
* @since Android 1.0
*/
public FilePermission(String path, String actions) {
super(path);
init(path, actions);
}
private void init(final String path, String pathActions) {
if (pathActions == null || pathActions.equals("")) { //$NON-NLS-1$
throw new IllegalArgumentException(Msg.getString("K006d")); //$NON-NLS-1$
}
this.actions = toCanonicalActionString(pathActions);
if (path == null) {
throw new NullPointerException(Msg.getString("K006e")); //$NON-NLS-1$
}
if (path.equals("<<ALL FILES>>")) { //$NON-NLS-1$
includeAll = true;
} else {
canonPath = AccessController
.doPrivileged(new PrivilegedAction<String>() {
public String run() {
try {
return new File(path).getCanonicalPath();
} catch (IOException e) {
return path;
}
}
});
if (path.equals("*") || path.endsWith(File.separator + "*")) { //$NON-NLS-1$ //$NON-NLS-2$
allDir = true;
}
if (path.equals("-") || path.endsWith(File.separator + "-")) { //$NON-NLS-1$ //$NON-NLS-2$
allSubdir = true;
}
}
}
/**
* Returns the string representing this permission's actions. It must be of
* the form "read,write,execute,delete", all lower case and in the correct
* order if there is more than one action.
*
* @param action
* the action name
* @return the string representing this permission's actions
*/
private String toCanonicalActionString(String action) {
actions = action.trim().toLowerCase();
// get the numerical representation of the action list
mask = getMask(actions);
// convert the mask to a canonical action list.
int len = actionList.length;
// the test mask - shift the 1 to the leftmost position of the
// actionList
int highestBitMask = 1 << (len - 1);
// if a bit of mask is set, append the corresponding action to result
StringBuilder result = new StringBuilder();
boolean addedItem = false;
for (int i = 0; i < len; i++) {
if ((highestBitMask & mask) != 0) {
if (addedItem) {
result.append(","); //$NON-NLS-1$
}
result.append(actionList[i]);
addedItem = true;
}
highestBitMask = highestBitMask >> 1;
}
return result.toString();
}
/**
* Returns the numerical representation of the argument.
*
* @param actionNames
* the action names
* @return the action mask
*/
private int getMask(String actionNames) {
int actionInt = 0, head = 0, tail = 0;
do {
tail = actionNames.indexOf(",", head); //$NON-NLS-1$
String action = tail > 0 ? actionNames.substring(head, tail).trim()
: actionNames.substring(head).trim();
if (action.equals("read")) { //$NON-NLS-1$
actionInt |= 8;
} else if (action.equals("write")) { //$NON-NLS-1$
actionInt |= 4;
} else if (action.equals("execute")) { //$NON-NLS-1$
actionInt |= 2;
} else if (action.equals("delete")) { //$NON-NLS-1$
actionInt |= 1;
} else {
throw new IllegalArgumentException(Msg.getString(
"K006f", action)); //$NON-NLS-1$
}
head = tail + 1;
} while (tail > 0);
return actionInt;
}
/**
* Returns the actions associated with this file permission.
*
* @return the actions associated with this file permission.
* @since Android 1.0
*/
@Override
public String getActions() {
return actions;
}
/**
* Indicates if this file permission is equal to another. The two are equal
* if {@code obj} is a FilePermission, they have the same path, and they
* have the same actions.
*
* @param obj
* the object to check equality with.
* @return {@code true} if this file permission is equal to {@code obj},
* {@code false} otherwise.
* @since Android 1.0
*/
@Override
public boolean equals(Object obj) {
if (obj instanceof FilePermission) {
FilePermission fp = (FilePermission) obj;
if (fp.actions != actions) {
if (fp.actions == null || !fp.actions.equals(actions)) {
return false;
}
}
/* Matching actions and both are <<ALL FILES>> ? */
if (fp.includeAll || includeAll) {
return fp.includeAll == includeAll;
}
return fp.canonPath.equals(canonPath);
}
return false;
}
/**
* Indicates whether the permission {@code p} is implied by this file
* permission. This is the case if {@code p} is an instance of
* {@code FilePermission}, if {@code p}'s actions are a subset of this
* file permission's actions and if {@code p}'s path is implied by this
* file permission's path.
*
* @param p
* the permission to check.
* @return {@code true} if the argument permission is implied by the
* receiver, and {@code false} if it is not.
* @since Android 1.0
*/
@Override
public boolean implies(Permission p) {
int match = impliesMask(p);
return match != 0 && match == ((FilePermission) p).mask;
}
/**
* Returns an int describing what masks are implied by a specific
* permission.
*
* @param p
* the permission
* @return the mask applied to the given permission
*/
int impliesMask(Permission p) {
if (!(p instanceof FilePermission)) {
return 0;
}
FilePermission fp = (FilePermission) p;
int matchedMask = mask & fp.mask;
// Can't match any bits?
if (matchedMask == 0) {
return 0;
}
// Is this permission <<ALL FILES>>
if (includeAll) {
return matchedMask;
}
// We can't imply all files
if (fp.includeAll) {
return 0;
}
// Scan the length of p checking all match possibilities
// \- implies everything except \
int thisLength = canonPath.length();
if (allSubdir && thisLength == 2
&& !fp.canonPath.equals(File.separator)) {
return matchedMask;
}
// need /- to imply /-
if (fp.allSubdir && !allSubdir) {
return 0;
}
// need /- or /* to imply /*
if (fp.allDir && !allSubdir && !allDir) {
return 0;
}
boolean includeDir = false;
int pLength = fp.canonPath.length();
// do not compare the * or -
if (allDir || allSubdir) {
thisLength--;
}
if (fp.allDir || fp.allSubdir) {
pLength--;
}
for (int i = 0; i < pLength; i++) {
char pChar = fp.canonPath.charAt(i);
// Is p longer than this permissions canonLength?
if (i >= thisLength) {
if (i == thisLength) {
// Is this permission include all? (must have matched up
// until this point).
if (allSubdir) {
return matchedMask;
}
// Is this permission include a dir? Continue the check
// afterwards.
if (allDir) {
includeDir = true;
}
}
// If not includeDir then is has to be a mismatch.
if (!includeDir) {
return 0;
}
/**
* If we have * for this and find a separator it is invalid. IE:
* this is '/a/*' and p is '/a/b/c' we should fail on the
* separator after the b. Except for root, canonical paths do
* not end in a separator.
*/
if (pChar == File.separatorChar) {
return 0;
}
} else {
// Are the characters matched?
if (canonPath.charAt(i) != pChar) {
return 0;
}
}
}
// Must have matched up to this point or it's a valid file in an include
// all directory
if (pLength == thisLength) {
if (allSubdir) {
// /- implies /- or /*
return fp.allSubdir || fp.allDir ? matchedMask : 0;
}
return allDir == fp.allDir ? matchedMask : 0;
}
return includeDir ? matchedMask : 0;
}
/**
* Returns a new PermissionCollection in which to place FilePermission
* objects.
*
* @return A new PermissionCollection object suitable for storing
* FilePermission objects.
* @since Android 1.0
*/
@Override
public PermissionCollection newPermissionCollection() {
return new FilePermissionCollection();
}
/**
* Calculates the hash code value for this file permission.
*
* @return the hash code value for this file permission.
* @since Android 1.0
*/
@Override
public int hashCode() {
return (canonPath == null ? getName().hashCode() : canonPath.hashCode())
+ mask;
}
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
}
private void readObject(ObjectInputStream stream) throws IOException,
ClassNotFoundException {
stream.defaultReadObject();
init(getName(), actions);
}
}
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