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/*
 * Copyright (c) OSGi Alliance (2002, 2013). All Rights Reserved.
 *
 * Licensed 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.osgi.service.wireadmin;

import java.io.IOException;
import java.security.BasicPermission;
import java.security.Permission;
import java.security.PermissionCollection;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * Permission for the scope of a {@code Wire} object. When a {@code Envelope}
 * object is used for communication with the {@code poll} or {@code update}
 * method, and the scope is set, then the {@code Wire} object must verify that
 * the Consumer service has {@code WirePermission[name,CONSUME]} and the
 * Producer service has {@code WirePermission[name,PRODUCE]} for all names in
 * the scope.
 * 

* The names are compared with the normal rules for permission names. This means * that they may end with a "*" to indicate wildcards. E.g. Door.* indicates all * scope names starting with the string "Door". The last period is required due * to the implementations of the {@code BasicPermission} class. * * @ThreadSafe * @author $Id: 99a7e308be87b5c34045f4d0ab6f2dd1bf3cd425 $ */ final public class WirePermission extends BasicPermission { static final long serialVersionUID = -5583709391516569321L; /** * The action string for the {@code produce} action. */ public static final String PRODUCE = "produce"; /** * The action string for the {@code consume} action. */ public static final String CONSUME = "consume"; private final static int ACTION_PRODUCE = 0x00000001; private final static int ACTION_CONSUME = 0x00000002; private final static int ACTION_ALL = ACTION_PRODUCE | ACTION_CONSUME; private final static int ACTION_NONE = 0; /** * The actions mask. */ private transient int action_mask; /** * The actions in canonical form. * * @serial */ private volatile String actions = null; /** * Create a new WirePermission with the given name (may be wildcard) and * actions. * * @param name Wire name. * @param actions {@code produce}, {@code consume} (canonical order). */ public WirePermission(String name, String actions) { this(name, parseActions(actions)); } /** * Package private constructor used by WirePermissionCollection. * * @param name class name * @param mask action mask */ WirePermission(String name, int mask) { super(name); setTransients(mask); } /** * Called by constructors and when deserialized. * * @param mask action mask */ private synchronized void setTransients(int mask) { if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) { throw new IllegalArgumentException("invalid action string"); } action_mask = mask; } /** * Returns the current action mask. Used by the WirePermissionCollection * object. * * @return The actions mask. */ synchronized int getActionsMask() { return action_mask; } /** * Parse action string into action mask. * * @param actions Action string. * @return action mask. */ private static int parseActions(String actions) { boolean seencomma = false; int mask = ACTION_NONE; if (actions == null) { return mask; } char[] a = actions.toCharArray(); int i = a.length - 1; if (i < 0) return mask; while (i != -1) { char c; // skip whitespace while ((i != -1) && ((c = a[i]) == ' ' || c == '\r' || c == '\n' || c == '\f' || c == '\t')) i--; // check for the known strings int matchlen; if (i >= 6 && (a[i - 6] == 'p' || a[i - 6] == 'P') && (a[i - 5] == 'r' || a[i - 5] == 'R') && (a[i - 4] == 'o' || a[i - 4] == 'O') && (a[i - 3] == 'd' || a[i - 3] == 'D') && (a[i - 2] == 'u' || a[i - 2] == 'U') && (a[i - 1] == 'c' || a[i - 1] == 'C') && (a[i] == 'e' || a[i] == 'E')) { matchlen = 7; mask |= ACTION_PRODUCE; } else if (i >= 6 && (a[i - 6] == 'c' || a[i - 6] == 'C') && (a[i - 5] == 'o' || a[i - 5] == 'O') && (a[i - 4] == 'n' || a[i - 4] == 'N') && (a[i - 3] == 's' || a[i - 3] == 'S') && (a[i - 2] == 'u' || a[i - 2] == 'U') && (a[i - 1] == 'm' || a[i - 1] == 'M') && (a[i] == 'e' || a[i] == 'E')) { matchlen = 7; mask |= ACTION_CONSUME; } else { // parse error throw new IllegalArgumentException("invalid permission: " + actions); } // make sure we didn't just match the tail of a word // like "ackbarfregister". Also, skip to the comma. seencomma = false; while (i >= matchlen && !seencomma) { switch (a[i - matchlen]) { case ',' : seencomma = true; /* FALLTHROUGH */ case ' ' : case '\r' : case '\n' : case '\f' : case '\t' : break; default : throw new IllegalArgumentException("invalid permission: " + actions); } i--; } // point i at the location of the comma minus one (or -1). i -= matchlen; } if (seencomma) { throw new IllegalArgumentException("invalid permission: " + actions); } return mask; } /** * Checks if this {@code WirePermission} object {@code implies} the * specified permission. *

* More specifically, this method returns {@code true} if: *

*

    *
  • p is an instanceof the {@code WirePermission} class,
  • *
  • p's actions are a proper subset of this object's actions, and
  • *
  • p's name is implied by this object's name. For example, * {@code java.*} implies {@code java.home}.
  • *
* * @param p The permission to check against. * * @return {@code true} if the specified permission is implied by this * object; {@code false} otherwise. */ public boolean implies(Permission p) { if (p instanceof WirePermission) { WirePermission requested = (WirePermission) p; int requestedMask = requested.getActionsMask(); return ((getActionsMask() & requestedMask) == requestedMask) && super.implies(p); } return false; } /** * Returns the canonical string representation of the actions. Always * returns present actions in the following order: {@code produce}, * {@code consume}. * * @return The canonical string representation of the actions. */ public String getActions() { String result = actions; if (result == null) { StringBuffer sb = new StringBuffer(); boolean comma = false; int mask = getActionsMask(); if ((mask & ACTION_PRODUCE) == ACTION_PRODUCE) { sb.append(PRODUCE); comma = true; } if ((mask & ACTION_CONSUME) == ACTION_CONSUME) { if (comma) sb.append(','); sb.append(CONSUME); } actions = result = sb.toString(); } return result; } /** * Returns a new {@code PermissionCollection} object for storing * {@code WirePermission} objects. * * @return A new {@code PermissionCollection} object suitable for storing * {@code WirePermission} objects. */ public PermissionCollection newPermissionCollection() { return new WirePermissionCollection(); } /** * Determines the equalty of two {@code WirePermission} objects. * * Checks that specified object has the same name and actions as this * {@code WirePermission} object. * * @param obj The object to test for equality. * @return true if {@code obj} is a {@code WirePermission}, and has the same * name and actions as this {@code WirePermission} object; * {@code false} otherwise. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof WirePermission)) { return false; } WirePermission wp = (WirePermission) obj; return (getActionsMask() == wp.getActionsMask()) && getName().equals(wp.getName()); } /** * Returns the hash code value for this object. * * @return Hash code value for this object. */ public int hashCode() { int h = 31 * 17 + getName().hashCode(); h = 31 * h + getActions().hashCode(); return h; } /** * Returns a string describing this {@code WirePermission}. The convention * is to specify the class name, the permission name, and the actions in the * following format: '(org.osgi.service.wireadmin.WirePermission * "name" "actions")'. * * @return information about this {@code Permission} object. */ public String toString() { StringBuffer sb = new StringBuffer(); sb.append('('); sb.append(getClass().getName()); sb.append(" \""); sb.append(getName()); String a = getActions(); if (a.length() > 0) { sb.append("\" \""); sb.append(a); } sb.append("\")"); return sb.toString(); } /** * WriteObject is called to save the state of the ServicePermission to a * stream. The actions are serialized, and the superclass takes care of the * name. */ private synchronized void writeObject(java.io.ObjectOutputStream s) throws IOException { // Write out the actions. The superclass takes care of the name // call getActions to make sure actions field is initialized if (actions == null) getActions(); s.defaultWriteObject(); } /** * readObject is called to restore the state of the ServicePermission from a * stream. */ private synchronized void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException { // Read in the action, then initialize the rest s.defaultReadObject(); setTransients(parseActions(actions)); } } /** * A {@code WirePermissionCollection} stores a set of {@code WirePermission} * permissions. */ final class WirePermissionCollection extends PermissionCollection { static final long serialVersionUID = 2617521094909826016L; /** * Table of permissions. * * @GuardedBy this * @serial */ private final Hashtable permissions; /** * Boolean saying if "*" is in the collection. * * @GuardedBy this * @serial */ private boolean all_allowed; /** * Creates an empty WirePermissionCollection object. * */ public WirePermissionCollection() { permissions = new Hashtable(); all_allowed = false; } /** * Adds a permission to this PermissionCollection. * * @param permission The Permission object to add. * * @throws IllegalArgumentException If the permission is not a * WirePermission object. * * @throws SecurityException If this PermissionCollection has been marked * read-only. */ public void add(Permission permission) { if (!(permission instanceof WirePermission)) { throw new IllegalArgumentException("invalid permission: " + permission); } if (isReadOnly()) { throw new SecurityException("attempt to add a Permission to a " + "readonly PermissionCollection"); } WirePermission wp = (WirePermission) permission; String name = wp.getName(); synchronized (this) { WirePermission existing = (WirePermission) permissions.get(name); if (existing != null) { int oldMask = existing.getActionsMask(); int newMask = wp.getActionsMask(); if (oldMask != newMask) { permissions.put(name, new WirePermission(name, oldMask | newMask)); } } else { permissions.put(name, wp); } if (!all_allowed) { if (name.equals("*")) { all_allowed = true; } } } } /** * Determines if a set of permissions implies the permissions expressed in * {@code permission}. * * @param permission The Permission object to compare. * * @return {@code true} if {@code permission} is a proper subset of a * permission in the set; {@code false} otherwise. */ public boolean implies(Permission permission) { if (!(permission instanceof WirePermission)) { return false; } WirePermission requested = (WirePermission) permission; WirePermission x; int desired = requested.getActionsMask(); int effective = 0; String name = requested.getName(); synchronized (this) { // short circuit if the "*" Permission was added if (all_allowed) { x = (WirePermission) permissions.get("*"); if (x != null) { effective |= x.getActionsMask(); if ((effective & desired) == desired) return true; } } // strategy: // Check for full match first. Then work our way up the // name looking for matches on a.b.* x = (WirePermission) permissions.get(name); } if (x != null) { // we have a direct hit! effective |= x.getActionsMask(); if ((effective & desired) == desired) { return true; } } // work our way up the tree... int last; int offset = name.length() - 1; while ((last = name.lastIndexOf(".", offset)) != -1) { name = name.substring(0, last + 1) + "*"; synchronized (this) { x = (WirePermission) permissions.get(name); } if (x != null) { effective |= x.getActionsMask(); if ((effective & desired) == desired) { return (true); } } offset = last - 1; } // we don't have to check for "*" as it was already checked // at the top (all_allowed), so we just return false return false; } /** * Returns an enumeration of all the Permission objects in the container. * * @return Enumeration of all the Permission objects. */ public Enumeration elements() { return permissions.elements(); } }




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