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/*
 * Copyright (c) OSGi Alliance (2000, 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.subsystem;

import java.io.IOException;
import java.io.NotSerializableException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.security.AccessController;
import java.security.BasicPermission;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.osgi.framework.Filter;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.InvalidSyntaxException;

/**
 * A bundle's authority to perform specific privileged administrative operations
 * on or to get sensitive information about a subsystem. The actions for this
 * permission are:
 * 
 * 
 * Action    Methods
 * context   Subsystem.getBundleContext
 * execute   Subsystem.start
 *           Subsystem.stop
 * lifecycle Subsystem.install
 *           Subsystem.uninstall
 * metadata  Subsystem.getHeaders
 *           Subsystem.getLocation
 * 
* *

* The name of this permission is a filter expression. The filter gives access * to the following attributes: *

    *
  • location - The location of a subsystem.
  • *
  • id - The subsystem ID of the designated subsystem.
  • *
  • name - The symbolic name of a subsystem.
  • *
* Filter attribute names are processed in a case sensitive manner. * * @ThreadSafe * @author $Id: 29c3097457160250e064b8c44696dbe86240c0ca $ */ public final class SubsystemPermission extends BasicPermission { static final long serialVersionUID = 307051004521261705L; /** * The action string {@code execute}. */ public final static String EXECUTE = "execute"; /** * The action string {@code lifecycle}. */ public final static String LIFECYCLE = "lifecycle"; /** * The action string {@code metadata}. */ public final static String METADATA = "metadata"; /** * The action string {@code context}. */ public final static String CONTEXT = "context"; private final static int ACTION_EXECUTE = 0x00000001; private final static int ACTION_LIFECYCLE = 0x00000002; private final static int ACTION_METADATA = 0x00000004; private final static int ACTION_CONTEXT = 0x00000008; private final static int ACTION_ALL = ACTION_EXECUTE | ACTION_LIFECYCLE | ACTION_METADATA | ACTION_CONTEXT; final static int ACTION_NONE = 0; /** * The actions in canonical form. * * @serial */ private volatile String actions = null; /** * The actions mask. */ transient int action_mask; /** * If this SubsystemPermission was constructed with a filter, this holds a * Filter matching object used to evaluate the filter in implies. */ transient Filter filter; /** * The subsystem governed by this SubsystemPermission - only used if filter * == null */ transient final Subsystem subsystem; /** * This map holds the properties of the permission, used to match a filter * in implies. This is not initialized until necessary, and then cached in * this object. */ private transient volatile Map properties; /** * ThreadLocal used to determine if we have recursively called * getProperties. */ private static final ThreadLocal recurse = new ThreadLocal(); /** * Create a new SubsystemPermission. * * This constructor must only be used to create a permission that is going * to be checked. *

* Examples: * *

	 * (name=com.acme.*)(location=http://www.acme.com/subsystems/*))
	 * (id>=1)
	 * 
* * @param filter A filter expression that can use, location, id, and name * keys. Filter attribute names are processed in a case sensitive * manner. A special value of {@code "*"} can be used to match all * subsystems. * @param actions {@code execute}, {@code lifecycle}, {@code metadata}, or * {@code context}. * @throws IllegalArgumentException If the filter has an invalid syntax. */ public SubsystemPermission(String filter, String actions) { this(parseFilter(filter), parseActions(actions)); } /** * Creates a new requested {@code SubsystemPermission} object to be used by * the code that must perform {@code checkPermission}. * {@code SubsystemPermission} objects created with this constructor cannot * be added to an {@code SubsystemPermission} permission collection. * * @param subsystem A subsystem. * @param actions {@code execute}, {@code lifecycle}, {@code metadata}, or * {@code context}. */ public SubsystemPermission(Subsystem subsystem, String actions) { super(createName(subsystem)); setTransients(null, parseActions(actions)); this.subsystem = subsystem; } /** * Create a permission name from a Subsystem * * @param subsystem Subsystem to use to create permission name. * @return permission name. */ private static String createName(Subsystem subsystem) { if (subsystem == null) { throw new IllegalArgumentException("subsystem must not be null"); } StringBuffer sb = new StringBuffer("(id="); sb.append(subsystem.getSubsystemId()); sb.append(")"); return sb.toString(); } /** * Package private constructor used by SubsystemPermissionCollection. * * @param filter name filter or {@code null} for wildcard. * @param mask action mask */ SubsystemPermission(Filter filter, int mask) { super((filter == null) ? "*" : filter.toString()); setTransients(filter, mask); this.subsystem = null; } /** * Called by constructors and when deserialized. * * @param filter Permission's filter or {@code null} for wildcard. * @param mask action mask */ private void setTransients(Filter filter, int mask) { this.filter = filter; if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) { throw new IllegalArgumentException("invalid action string"); } this.action_mask = 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] == 'e' || a[i - 6] == 'E') && (a[i - 5] == 'x' || a[i - 5] == 'X') && (a[i - 4] == 'e' || a[i - 4] == 'E') && (a[i - 3] == 'c' || a[i - 3] == 'C') && (a[i - 2] == 'u' || a[i - 2] == 'U') && (a[i - 1] == 't' || a[i - 1] == 'T') && (a[i] == 'e' || a[i] == 'E')) { matchlen = 7; mask |= ACTION_EXECUTE; } else if (i >= 8 && (a[i - 8] == 'l' || a[i - 8] == 'L') && (a[i - 7] == 'i' || a[i - 7] == 'I') && (a[i - 6] == 'f' || a[i - 6] == 'F') && (a[i - 5] == 'e' || a[i - 5] == 'E') && (a[i - 4] == 'c' || a[i - 4] == 'C') && (a[i - 3] == 'y' || a[i - 3] == 'Y') && (a[i - 2] == 'c' || a[i - 2] == 'C') && (a[i - 1] == 'l' || a[i - 1] == 'L') && (a[i] == 'e' || a[i] == 'E')) { matchlen = 9; mask |= ACTION_LIFECYCLE; } else if (i >= 7 && (a[i - 7] == 'm' || a[i - 7] == 'M') && (a[i - 6] == 'e' || a[i - 6] == 'E') && (a[i - 5] == 't' || a[i - 5] == 'T') && (a[i - 4] == 'a' || a[i - 4] == 'A') && (a[i - 3] == 'd' || a[i - 3] == 'D') && (a[i - 2] == 'a' || a[i - 2] == 'A') && (a[i - 1] == 't' || a[i - 1] == 'T') && (a[i] == 'a' || a[i] == 'A')) { matchlen = 8; mask |= ACTION_METADATA; } 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] == 't' || a[i - 3] == 'T') && (a[i - 2] == 'e' || a[i - 2] == 'E') && (a[i - 1] == 'x' || a[i - 1] == 'X') && (a[i] == 't' || a[i] == 'T')) { matchlen = 7; mask |= ACTION_CONTEXT; } else { // parse error throw new IllegalArgumentException("invalid permission: " + actions); } // make sure we didn't just match the tail of a word // like "ackbarfexecute". 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; } /** * Parse filter string into a Filter object. * * @param filterString The filter string to parse. * @return a Filter for this subsystem. If the specified filterString equals * "*", then {@code null} is returned to indicate a wildcard. * @throws IllegalArgumentException If the filter syntax is invalid. */ private static Filter parseFilter(String filterString) { filterString = filterString.trim(); if (filterString.equals("*")) { return null; } try { return FrameworkUtil.createFilter(filterString); } catch (InvalidSyntaxException e) { IllegalArgumentException iae = new IllegalArgumentException("invalid filter"); iae.initCause(e); throw iae; } } /** * Determines if the specified permission is implied by this object. This * method throws an exception if the specified permission was not * constructed with a subsystem. * *

* This method returns {@code true} if the specified permission is a * SubsystemPermission AND *

    *
  • this object's filter matches the specified permission's subsystem ID, * subsystem symbolic name, and subsystem location OR
  • *
  • this object's filter is "*"
  • *
* AND this object's actions include all of the specified permission's * actions. *

* Special case: if the specified permission was constructed with "*" * filter, then this method returns {@code true} if this object's filter is * "*" and this object's actions include all of the specified permission's * actions * * @param p The requested permission. * @return {@code true} if the specified permission is implied by this * object; {@code false} otherwise. */ public boolean implies(Permission p) { if (!(p instanceof SubsystemPermission)) { return false; } SubsystemPermission requested = (SubsystemPermission) p; if (subsystem != null) { return false; } // if requested permission has a filter, then it is an invalid argument if (requested.filter != null) { return false; } return implies0(requested, ACTION_NONE); } /** * Internal implies method. Used by the implies and the permission * collection implies methods. * * @param requested The requested SubsystemPermision which has already been * validated as a proper argument. The requested SubsystemPermission * must not have a filter expression. * @param effective The effective actions with which to start. * @return {@code true} if the specified permission is implied by this * object; {@code false} otherwise. */ boolean implies0(SubsystemPermission requested, int effective) { /* check actions first - much faster */ effective |= action_mask; final int desired = requested.action_mask; if ((effective & desired) != desired) { return false; } /* Get our filter */ Filter f = filter; if (f == null) { // it's "*" return true; } /* is requested a wildcard filter? */ if (requested.subsystem == null) { return false; } Map requestedProperties = requested.getProperties(); if (requestedProperties == null) { /* * If the requested properties are null, then we have detected a * recursion getting the subsystem location. So we return true to * permit the subsystem location request in the SubsystemPermission * check up the stack to succeed. */ return true; } return f.matches(requestedProperties); } /** * Returns the canonical string representation of the * {@code SubsystemPermission} actions. * *

* Always returns present {@code SubsystemPermission} actions in the * following order: {@code execute}, {@code lifecycle}, {@code metadata}, * {@code context}. * * @return Canonical string representation of the * {@code SubsystemPermission} actions. */ public String getActions() { String result = actions; if (result == null) { StringBuffer sb = new StringBuffer(); int mask = action_mask; if ((mask & ACTION_EXECUTE) == ACTION_EXECUTE) { sb.append(EXECUTE); sb.append(','); } if ((mask & ACTION_LIFECYCLE) == ACTION_LIFECYCLE) { sb.append(LIFECYCLE); sb.append(','); } if ((mask & ACTION_METADATA) == ACTION_METADATA) { sb.append(METADATA); sb.append(','); } if ((mask & ACTION_CONTEXT) == ACTION_CONTEXT) { sb.append(CONTEXT); sb.append(','); } // remove trailing comma if (sb.length() > 0) { sb.setLength(sb.length() - 1); } actions = result = sb.toString(); } return result; } /** * Returns a new {@code PermissionCollection} object suitable for storing * {@code SubsystemPermission}s. * * @return A new {@code PermissionCollection} object. */ public PermissionCollection newPermissionCollection() { return new SubsystemPermissionCollection(); } /** * Determines the equality of two {@code SubsystemPermission} objects. * * @param obj The object being compared for equality with this object. * @return {@code true} if {@code obj} is equivalent to this * {@code SubsystemPermission}; {@code false} otherwise. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof SubsystemPermission)) { return false; } SubsystemPermission sp = (SubsystemPermission) obj; return (action_mask == sp.action_mask) && ((subsystem == sp.subsystem) || ((subsystem != null) && subsystem.equals(sp.subsystem))) && (filter == null ? sp.filter == null : filter.equals(sp.filter)); } /** * 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(); if (subsystem != null) { h = 31 * h + subsystem.hashCode(); } return h; } /** * WriteObject is called to save the state of this permission object 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 { if (subsystem != null) { throw new NotSerializableException("cannot serialize"); } // 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 this permission from a * stream. */ private synchronized void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException { // Read in the data, then initialize the transients s.defaultReadObject(); setTransients(parseFilter(getName()), parseActions(actions)); } /** * Called by {@code implies0} on an SubsystemPermission which was * constructed with a Subsystem. This method loads a map with the * filter-matchable properties of this subsystem. The map is cached so this * lookup only happens once. * * This method should only be called on an SubsystemPermission which was * constructed with a subsystem * * @return a map of properties for this subsystem */ private Map getProperties() { Map result = properties; if (result != null) { return result; } /* * We may have recursed here due to the Subsystem.getLocation call in * the doPrivileged below. If this is the case, return null to allow * implies to return true. */ final Object mark = recurse.get(); if (mark == subsystem) { return null; } recurse.set(subsystem); try { final Map map = new HashMap(4); AccessController.doPrivileged(new PrivilegedAction() { public Object run() { map.put("id", new Long(subsystem.getSubsystemId())); map.put("location", subsystem.getLocation()); map.put("name", subsystem.getSymbolicName()); return null; } }); return properties = map; } finally { recurse.set(null); } } } /** * Stores a collection of {@code SubsystemPermission}s. */ final class SubsystemPermissionCollection extends PermissionCollection { private static final long serialVersionUID = 3906372644575328048L; /** * Collection of permissions. * * @GuardedBy this */ private transient Map permissions; /** * Boolean saying if "*" is in the collection. * * @serial * @GuardedBy this */ private boolean all_allowed; /** * Create an empty SubsystemPermissionCollection object. * */ public SubsystemPermissionCollection() { permissions = new HashMap(); } /** * Adds a permission to this permission collection. * * @param permission The {@code SubsystemPermission} object to add. * @throws IllegalArgumentException If the specified permission is not an * {@code SubsystemPermission} instance or was constructed with a * Subsystem object. * @throws SecurityException If this {@code SubsystemPermissionCollection} * object has been marked read-only. */ public void add(Permission permission) { if (!(permission instanceof SubsystemPermission)) { throw new IllegalArgumentException("invalid permission: " + permission); } if (isReadOnly()) { throw new SecurityException("attempt to add a Permission to a " + "readonly PermissionCollection"); } final SubsystemPermission sp = (SubsystemPermission) permission; if (sp.subsystem != null) { throw new IllegalArgumentException("cannot add to collection: " + sp); } final String name = sp.getName(); synchronized (this) { Map pc = permissions; SubsystemPermission existing = pc.get(name); if (existing != null) { int oldMask = existing.action_mask; int newMask = sp.action_mask; if (oldMask != newMask) { pc.put(name, new SubsystemPermission(existing.filter, oldMask | newMask)); } } else { pc.put(name, sp); } if (!all_allowed) { if (name.equals("*")) { all_allowed = true; } } } } /** * Determines if the specified permissions implies the permissions expressed * in {@code permission}. * * @param permission The Permission object to compare with the * {@code SubsystemPermission} objects in this collection. * @return {@code true} if {@code permission} is implied by an * {@code SubsystemPermission} in this collection, {@code false} * otherwise. */ public boolean implies(Permission permission) { if (!(permission instanceof SubsystemPermission)) { return false; } SubsystemPermission requested = (SubsystemPermission) permission; // if requested permission has a filter, then it is an invalid argument if (requested.filter != null) { return false; } int effective = SubsystemPermission.ACTION_NONE; Collection perms; synchronized (this) { Map pc = permissions; // short circuit if the "*" Permission was added if (all_allowed) { SubsystemPermission sp = pc.get("*"); if (sp != null) { effective |= sp.action_mask; final int desired = requested.action_mask; if ((effective & desired) == desired) { return true; } } } perms = pc.values(); } // just iterate one by one for (SubsystemPermission perm : perms) { if (perm.implies0(requested, effective)) { return true; } } return false; } /** * Returns an enumeration of all {@code SubsystemPermission} objects in the * container. * * @return Enumeration of all {@code SubsystemPermission} objects. */ public synchronized Enumeration elements() { List all = new ArrayList(permissions.values()); return Collections.enumeration(all); } /* serialization logic */ private static final ObjectStreamField[] serialPersistentFields = {new ObjectStreamField("permissions", HashMap.class), new ObjectStreamField("all_allowed", Boolean.TYPE)}; private synchronized void writeObject(ObjectOutputStream out) throws IOException { ObjectOutputStream.PutField pfields = out.putFields(); pfields.put("permissions", permissions); pfields.put("all_allowed", all_allowed); out.writeFields(); } private synchronized void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException { ObjectInputStream.GetField gfields = in.readFields(); HashMap p = (HashMap) gfields.get("permissions", null); permissions = p; all_allowed = gfields.get("all_allowed", false); } }