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/*
 * Copyright (c) OSGi Alliance (2000, 2009). 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.framework;

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.Dictionary;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * A bundle's authority to register or get a service.
 * 
    *
  • The register action allows a bundle to register a service on * the specified names. *
  • The get action allows a bundle to detect a service and get * it. *
* Permission to get a service is required in order to detect events regarding * the service. Untrusted bundles should not be able to detect the presence of * certain services unless they have the appropriate * ServicePermission to get the specific service. * * @ThreadSafe * @version $Revision: 7189 $ */ public final class ServicePermission extends BasicPermission { static final long serialVersionUID = -7662148639076511574L; /** * The action string get. */ public final static String GET = "get"; /** * The action string register. */ public final static String REGISTER = "register"; private final static int ACTION_GET = 0x00000001; private final static int ACTION_REGISTER = 0x00000002; private final static int ACTION_ALL = ACTION_GET | ACTION_REGISTER; final static int ACTION_NONE = 0; /** * The actions mask. */ transient int action_mask; /** * The actions in canonical form. * * @serial */ private volatile String actions = null; /** * The service used by this ServicePermission. Must be null if not * constructed with a service. */ transient final ServiceReference service; /** * The object classes for this ServicePermission. Must be null if not * constructed with a service. */ transient final String[] objectClass; /** * If this ServicePermission was constructed with a filter, this holds a * Filter matching object used to evaluate the filter in implies. */ transient Filter filter; /** * This dictionary 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 Dictionary properties; /** * True if constructed with a name and the name is "*" or ends with ".*". */ private transient boolean wildcard; /** * If constructed with a name and the name ends with ".*", this contains the * name without the final "*". */ private transient String prefix; /** * Create a new ServicePermission. * *

* The name of the service is specified as a fully qualified class name. * Wildcards may be used. * *

	 * name ::= <class name> | <class name ending in ".*"> | *
	 * 
* * Examples: * *
	 * org.osgi.service.http.HttpService
	 * org.osgi.service.http.*
	 * *
	 * 
* * For the get action, the name can also be a filter * expression. The filter gives access to the service properties as well as * the following attributes: *
    *
  • signer - A Distinguished Name chain used to sign the bundle * publishing the service. Wildcards in a DN are not matched according to * the filter string rules, but according to the rules defined for a DN * chain.
  • *
  • location - The location of the bundle publishing the service.
  • *
  • id - The bundle ID of the bundle publishing the service.
  • *
  • name - The symbolic name of the bundle publishing the service.
  • *
* Since the above attribute names may conflict with service property names * used by a service, you can prefix an attribute name with '@' in the * filter expression to match against the service property and not one of * the above attributes. Filter attribute names are processed in a case * sensitive manner unless the attribute references a service property. * Service properties names are case insensitive. * *

* There are two possible actions: get and * register. The get permission allows the owner * of this permission to obtain a service with this name. The * register permission allows the bundle to register a service * under that name. * * @param name The service class name * @param actions get,register (canonical order) * @throws IllegalArgumentException If the specified name is a filter * expression and either the specified action is not * get or the filter has an invalid syntax. */ public ServicePermission(String name, String actions) { this(name, parseActions(actions)); if ((filter != null) && ((action_mask & ACTION_ALL) != ACTION_GET)) { throw new IllegalArgumentException( "invalid action string for filter expression"); } } /** * Creates a new requested ServicePermission object to be used * by code that must perform checkPermission for the * get action. ServicePermission objects created * with this constructor cannot be added to a ServicePermission * permission collection. * * @param reference The requested service. * @param actions The action get. * @throws IllegalArgumentException If the specified action is not * get or reference is null. * @since 1.5 */ public ServicePermission(ServiceReference reference, String actions) { super(createName(reference)); setTransients(null, parseActions(actions)); this.service = reference; this.objectClass = (String[]) reference .getProperty(Constants.OBJECTCLASS); if ((action_mask & ACTION_ALL) != ACTION_GET) { throw new IllegalArgumentException("invalid action string"); } } /** * Create a permission name from a ServiceReference * * @param reference ServiceReference to use to create permission name. * @return permission name. */ private static String createName(ServiceReference reference) { if (reference == null) { throw new IllegalArgumentException("reference must not be null"); } StringBuffer sb = new StringBuffer("(service.id="); sb.append(reference.getProperty(Constants.SERVICE_ID)); sb.append(")"); return sb.toString(); } /** * Package private constructor used by ServicePermissionCollection. * * @param name class name * @param mask action mask */ ServicePermission(String name, int mask) { super(name); setTransients(parseFilter(name), mask); this.service = null; this.objectClass = null; } /** * Called by constructors and when deserialized. * * @param mask action mask */ private void setTransients(Filter f, int mask) { if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) { throw new IllegalArgumentException("invalid action string"); } action_mask = mask; filter = f; if (f == null) { String name = getName(); int l = name.length(); /* if "*" or endsWith ".*" */ wildcard = ((name.charAt(l - 1) == '*') && ((l == 1) || (name .charAt(l - 2) == '.'))); if (wildcard && (l > 1)) { prefix = name.substring(0, l - 1); } } } /** * 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 >= 2 && (a[i - 2] == 'g' || a[i - 2] == 'G') && (a[i - 1] == 'e' || a[i - 1] == 'E') && (a[i] == 't' || a[i] == 'T')) { matchlen = 3; mask |= ACTION_GET; } else if (i >= 7 && (a[i - 7] == 'r' || a[i - 7] == 'R') && (a[i - 6] == 'e' || a[i - 6] == 'E') && (a[i - 5] == 'g' || a[i - 5] == 'G') && (a[i - 4] == 'i' || a[i - 4] == 'I') && (a[i - 3] == 's' || a[i - 3] == 'S') && (a[i - 2] == 't' || a[i - 2] == 'T') && (a[i - 1] == 'e' || a[i - 1] == 'E') && (a[i] == 'r' || a[i] == 'R')) { matchlen = 8; mask |= ACTION_REGISTER; } 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; } /** * Parse filter string into a Filter object. * * @param filterString The filter string to parse. * @return a Filter for this bundle. If the specified filterString is not a * filter expression, then null is returned. * @throws IllegalArgumentException If the filter syntax is invalid. */ private static Filter parseFilter(String filterString) { filterString = filterString.trim(); if (filterString.charAt(0) != '(') { return null; } try { return FrameworkUtil.createFilter(filterString); } catch (InvalidSyntaxException e) { IllegalArgumentException iae = new IllegalArgumentException( "invalid filter"); iae.initCause(e); throw iae; } } /** * Determines if a ServicePermission object "implies" the * specified permission. * * @param p The target permission to check. * @return true if the specified permission is implied by this * object; false otherwise. */ public boolean implies(Permission p) { if (!(p instanceof ServicePermission)) { return false; } ServicePermission requested = (ServicePermission) p; if (service != 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 ServicePermission which has already be * validated as a proper argument. The requested ServicePermission * must not have a filter expression. * @param effective The effective actions with which to start. * @return true if the specified permission is implied by this * object; false otherwise. */ boolean implies0(ServicePermission requested, int effective) { /* check actions first - much faster */ effective |= action_mask; final int desired = requested.action_mask; if ((effective & desired) != desired) { return false; } /* we have name of "*" */ if (wildcard && (prefix == null)) { return true; } /* if we have a filter */ Filter f = filter; if (f != null) { return f.matchCase(requested.getProperties()); } /* if requested permission not created with ServiceReference */ String[] requestedNames = requested.objectClass; if (requestedNames == null) { return super.implies(requested); } /* requested permission created with ServiceReference */ if (wildcard) { int pl = prefix.length(); for (int i = 0, l = requestedNames.length; i < l; i++) { String requestedName = requestedNames[i]; if ((requestedName.length() > pl) && requestedName.startsWith(prefix)) { return true; } } } else { String name = getName(); for (int i = 0, l = requestedNames.length; i < l; i++) { if (requestedNames[i].equals(name)) { return true; } } } return false; } /** * Returns the canonical string representation of the actions. Always * returns present actions in the following order: get, * register. * * @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 = action_mask; if ((mask & ACTION_GET) == ACTION_GET) { sb.append(GET); comma = true; } if ((mask & ACTION_REGISTER) == ACTION_REGISTER) { if (comma) sb.append(','); sb.append(REGISTER); } actions = result = sb.toString(); } return result; } /** * Returns a new PermissionCollection object for storing * ServicePermission objects. * * @return A new PermissionCollection object suitable for storing * ServicePermission objects. */ public PermissionCollection newPermissionCollection() { return new ServicePermissionCollection(); } /** * Determines the equality of two ServicePermission objects. * * Checks that specified object has the same class name and action as this * ServicePermission. * * @param obj The object to test for equality. * @return true if obj is a ServicePermission, and has the same * class name and actions as this ServicePermission * object; false otherwise. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof ServicePermission)) { return false; } ServicePermission sp = (ServicePermission) obj; return (action_mask == sp.action_mask) && getName().equals(sp.getName()) && ((service == sp.service) || ((service != null) && (service .compareTo(sp.service) == 0))); } /** * 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 (service != null) { h = 31 * h + service.hashCode(); } return h; } /** * WriteObject is called to save the state of this permission 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 (service != 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 action, then initialize the rest s.defaultReadObject(); setTransients(parseFilter(getName()), parseActions(actions)); } /** * Called by <@link ServicePermission#implies(Permission)>. * * @return a dictionary of properties for this permission. */ private Dictionary getProperties() { Dictionary result = properties; if (result != null) { return result; } if (service == null) { result = new Hashtable(1); if (filter == null) { result.put(Constants.OBJECTCLASS, new String[] {getName()}); } return properties = result; } final Map props = new HashMap(4); final Bundle bundle = service.getBundle(); if (bundle != null) { AccessController.doPrivileged(new PrivilegedAction() { public Object run() { props.put("id", new Long(bundle.getBundleId())); props.put("location", bundle.getLocation()); String name = bundle.getSymbolicName(); if (name != null) { props.put("name", name); } SignerProperty signer = new SignerProperty(bundle); if (signer.isBundleSigned()) { props.put("signer", signer); } return null; } }); } return properties = new Properties(props, service); } private static class Properties extends Dictionary { private final Map properties; private final ServiceReference service; Properties(Map properties, ServiceReference service) { this.properties = properties; this.service = service; } public Object get(Object k) { if (!(k instanceof String)) { return null; } String key = (String) k; if (key.charAt(0) == '@') { return service.getProperty(key.substring(1)); } Object value = properties.get(key); if (value != null) { // fall back to service properties return value; } return service.getProperty(key); } public int size() { return properties.size() + service.getPropertyKeys().length; } public boolean isEmpty() { // we can return false because this must never be empty return false; } public Enumeration keys() { Collection pk = properties.keySet(); String spk[] = service.getPropertyKeys(); List all = new ArrayList(pk.size() + spk.length); all.addAll(pk); add: for (int i = 0, length = spk.length; i < length; i++) { String key = spk[i]; for (Iterator iter = pk.iterator(); iter.hasNext();) { if (key.equalsIgnoreCase((String) iter.next())) { continue add; } } all.add(key); } return Collections.enumeration(all); } public Enumeration elements() { Collection pk = properties.keySet(); String spk[] = service.getPropertyKeys(); List all = new ArrayList(pk.size() + spk.length); all.addAll(properties.values()); add: for (int i = 0, length = spk.length; i < length; i++) { String key = spk[i]; for (Iterator iter = pk.iterator(); iter.hasNext();) { if (key.equalsIgnoreCase((String) iter.next())) { continue add; } } all.add(service.getProperty(key)); } return Collections.enumeration(all); } public Object put(Object key, Object value) { throw new UnsupportedOperationException(); } public Object remove(Object key) { throw new UnsupportedOperationException(); } } } /** * Stores a set of ServicePermission permissions. * * @see java.security.Permission * @see java.security.Permissions * @see java.security.PermissionCollection */ final class ServicePermissionCollection extends PermissionCollection { static final long serialVersionUID = 662615640374640621L; /** * Table of permissions. * * @GuardedBy this */ private transient Map permissions; /** * Boolean saying if "*" is in the collection. * * @serial * @GuardedBy this */ private boolean all_allowed; /** * Table of permissions with filter expressions. * * @serial * @GuardedBy this */ private Map filterPermissions; /** * Creates an empty ServicePermissions object. */ public ServicePermissionCollection() { permissions = new HashMap(); all_allowed = false; } /** * Adds a permission to this permission collection. * * @param permission The Permission object to add. * @throws IllegalArgumentException If the specified permission is not a * ServicePermission object. * @throws SecurityException If this * ServicePermissionCollection object has been marked * read-only. */ public void add(final Permission permission) { if (!(permission instanceof ServicePermission)) { throw new IllegalArgumentException("invalid permission: " + permission); } if (isReadOnly()) { throw new SecurityException("attempt to add a Permission to a " + "readonly PermissionCollection"); } final ServicePermission sp = (ServicePermission) permission; if (sp.service != null) { throw new IllegalArgumentException("cannot add to collection: " + sp); } final String name = sp.getName(); final Filter f = sp.filter; synchronized (this) { /* select the bucket for the permission */ Map pc; if (f != null) { pc = filterPermissions; if (pc == null) { filterPermissions = pc = new HashMap(); } } else { pc = permissions; } final ServicePermission existing = (ServicePermission) pc.get(name); if (existing != null) { final int oldMask = existing.action_mask; final int newMask = sp.action_mask; if (oldMask != newMask) { pc .put(name, new ServicePermission(name, oldMask | newMask)); } } else { pc.put(name, sp); } if (!all_allowed) { if (name.equals("*")) { all_allowed = true; } } } } /** * Determines if a set of permissions implies the permissions expressed in * permission. * * @param permission The Permission object to compare. * @return true if permission is a proper * subset of a permission in the set; false * otherwise. */ public boolean implies(final Permission permission) { if (!(permission instanceof ServicePermission)) { return false; } final ServicePermission requested = (ServicePermission) permission; /* if requested permission has a filter, then it is an invalid argument */ if (requested.filter != null) { return false; } int effective = ServicePermission.ACTION_NONE; Collection perms; synchronized (this) { final int desired = requested.action_mask; /* short circuit if the "*" Permission was added */ if (all_allowed) { ServicePermission sp = (ServicePermission) permissions.get("*"); if (sp != null) { effective |= sp.action_mask; if ((effective & desired) == desired) { return true; } } } String[] requestedNames = requested.objectClass; /* if requested permission not created with ServiceReference */ if (requestedNames == null) { effective |= effective(requested.getName(), desired, effective); if ((effective & desired) == desired) { return true; } } /* requested permission created with ServiceReference */ else { for (int i = 0, l = requestedNames.length; i < l; i++) { if ((effective(requestedNames[i], desired, effective) & desired) == desired) { return true; } } } Map pc = filterPermissions; if (pc == null) { return false; } perms = pc.values(); } /* iterate one by one over filteredPermissions */ for (Iterator iter = perms.iterator(); iter.hasNext();) { if (((ServicePermission) iter.next()) .implies0(requested, effective)) { return true; } } return false; } /** * Consult permissions map to compute the effective permission for the * requested permission name. * * @param requestedName The requested service name. * @param desired The desired actions. * @param effective The effective actions. * @return The new effective actions. */ private int effective(String requestedName, final int desired, int effective) { final Map pc = permissions; ServicePermission sp = (ServicePermission) pc.get(requestedName); // strategy: // Check for full match first. Then work our way up the // name looking for matches on a.b.* if (sp != null) { // we have a direct hit! effective |= sp.action_mask; if ((effective & desired) == desired) { return effective; } } // work our way up the tree... int last; int offset = requestedName.length() - 1; while ((last = requestedName.lastIndexOf(".", offset)) != -1) { requestedName = requestedName.substring(0, last + 1) + "*"; sp = (ServicePermission) pc.get(requestedName); if (sp != null) { effective |= sp.action_mask; if ((effective & desired) == desired) { return effective; } } offset = last - 1; } /* * we don't have to check for "*" as it was already checked before we * were called. */ return effective; } /** * Returns an enumeration of all the ServicePermission * objects in the container. * * @return Enumeration of all the ServicePermission objects. */ public synchronized Enumeration elements() { List all = new ArrayList(permissions.values()); Map pc = filterPermissions; if (pc != null) { all.addAll(pc.values()); } return Collections.enumeration(all); } /* serialization logic */ private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField("permissions", Hashtable.class), new ObjectStreamField("all_allowed", Boolean.TYPE), new ObjectStreamField("filterPermissions", HashMap.class) }; private synchronized void writeObject(ObjectOutputStream out) throws IOException { Hashtable hashtable = new Hashtable(permissions); ObjectOutputStream.PutField pfields = out.putFields(); pfields.put("permissions", hashtable); pfields.put("all_allowed", all_allowed); pfields.put("filterPermissions", filterPermissions); out.writeFields(); } private synchronized void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException { ObjectInputStream.GetField gfields = in.readFields(); Hashtable hashtable = (Hashtable) gfields.get("permissions", null); permissions = new HashMap(hashtable); all_allowed = gfields.get("all_allowed", false); filterPermissions = (HashMap) gfields.get("filterPermissions", null); } }