blob: 9258b4cef7cc0869bc83078f0d0be6621a85e40a [file] [log] [blame]
/*
* $Header: /cvshome/build/org.osgi.framework/src/org/osgi/framework/ServicePermission.java,v 1.15 2007/02/20 00:06:02 hargrave Exp $
*
* Copyright (c) OSGi Alliance (2000, 2007). 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.security.*;
import java.util.Enumeration;
import java.util.Hashtable;
/**
* A bundle's authority to register or get a service.
* <ul>
* <li>The <code>ServicePermission.REGISTER</code> action allows a bundle to
* register a service on the specified names.
* <li>The <code>ServicePermission.GET</code> action allows a bundle to
* detect a service and get it.
* </ul>
* 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
* <code>ServicePermission</code> to get the specific service.
*
* @version $Revision: 1.15 $
*/
final public class ServicePermission extends BasicPermission {
static final long serialVersionUID = -7662148639076511574L;
/**
* The action string <code>get</code> (Value is "get").
*/
public final static String GET = "get";
/**
* The action string <code>register</code> (Value is "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;
private final static int ACTION_NONE = 0;
/**
* The actions mask.
*/
private transient int action_mask = ACTION_NONE;
/**
* The actions in canonical form.
*
* @serial
*/
private String actions = null;
/**
* Create a new ServicePermission.
*
* <p>
* The name of the service is specified as a fully qualified class name.
*
* <pre>
* ClassName ::= &lt;class name&gt; | &lt;class name ending in &quot;.*&quot;&gt;
* </pre>
*
* Examples:
*
* <pre>
* org.osgi.service.http.HttpService
* org.osgi.service.http.*
* org.osgi.service.snmp.*
* </pre>
*
* <p>
* There are two possible actions: <code>get</code> and
* <code>register</code>. The <code>get</code> permission allows the
* owner of this permission to obtain a service with this name. The
* <code>register</code> permission allows the bundle to register a
* service under that name.
*
* @param name class name
* @param actions <code>get</code>,<code>register</code> (canonical
* order)
*/
public ServicePermission(String name, String actions) {
this(name, getMask(actions));
}
/**
* Package private constructor used by ServicePermissionCollection.
*
* @param name class name
* @param mask action mask
*/
ServicePermission(String name, int mask) {
super(name);
init(mask);
}
/**
* Called by constructors and when deserialized.
*
* @param mask action mask
*/
private void init(int mask) {
if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) {
throw new IllegalArgumentException("invalid action string");
}
action_mask = mask;
}
/**
* Parse action string into action mask.
*
* @param actions Action string.
* @return action mask.
*/
private static int getMask(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;
}
/**
* Determines if a <code>ServicePermission</code> object "implies" the
* specified permission.
*
* @param p The target permission to check.
* @return <code>true</code> if the specified permission is implied by
* this object; <code>false</code> otherwise.
*/
public boolean implies(Permission p) {
if (p instanceof ServicePermission) {
ServicePermission target = (ServicePermission) p;
return (((action_mask & target.action_mask) == target.action_mask) && super
.implies(p));
}
return (false);
}
/**
* Returns the canonical string representation of the actions. Always
* returns present actions in the following order: <code>get</code>,
* <code>register</code>.
*
* @return The canonical string representation of the actions.
*/
public String getActions() {
if (actions == null) {
StringBuffer sb = new StringBuffer();
boolean comma = false;
if ((action_mask & ACTION_GET) == ACTION_GET) {
sb.append(GET);
comma = true;
}
if ((action_mask & ACTION_REGISTER) == ACTION_REGISTER) {
if (comma)
sb.append(',');
sb.append(REGISTER);
}
actions = sb.toString();
}
return (actions);
}
/**
* Returns a new <code>PermissionCollection</code> object for storing
* <code>ServicePermission<code> objects.
*
* @return A new <code>PermissionCollection</code> object suitable for storing
* <code>ServicePermission</code> objects.
*/
public PermissionCollection newPermissionCollection() {
return (new ServicePermissionCollection());
}
/**
* Determines the equalty of two ServicePermission objects.
*
* Checks that specified object has the same class name and action as this
* <code>ServicePermission</code>.
*
* @param obj The object to test for equality.
* @return true if obj is a <code>ServicePermission</code>, and has the
* same class name and actions as this
* <code>ServicePermission</code> object; <code>false</code>
* otherwise.
*/
public boolean equals(Object obj) {
if (obj == this) {
return (true);
}
if (!(obj instanceof ServicePermission)) {
return (false);
}
ServicePermission p = (ServicePermission) obj;
return ((action_mask == p.action_mask) && getName().equals(p.getName()));
}
/**
* Returns the hash code value for this object.
*
* @return Hash code value for this object.
*/
public int hashCode() {
return (getName().hashCode() ^ getActions().hashCode());
}
/**
* Returns the current action mask. Used by the ServicePermissionCollection
* object.
*
* @return The actions mask.
*/
int getMask() {
return (action_mask);
}
/**
* 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 {
// 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();
init(getMask(actions));
}
}
/**
* 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.
*
* @serial
*/
private Hashtable<String,Permission> permissions;
/**
* Boolean saying if "*" is in the collection.
*
* @serial
*/
private boolean all_allowed;
/**
* Creates an empty ServicePermissions object.
*/
public ServicePermissionCollection() {
permissions = new Hashtable<String,Permission>();
all_allowed = false;
}
/**
* Adds a permission to the <code>ServicePermission</code> objects using
* the key for the hash as the name.
*
* @param permission The Permission object to add.
*
* @throws IllegalArgumentException If the permission is not a
* ServicePermission object.
* @throws SecurityException If this
* <code>ServicePermissionCollection</code> object has been marked
* read-only.
*/
public void add(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");
ServicePermission sp = (ServicePermission) permission;
String name = sp.getName();
ServicePermission existing = (ServicePermission) permissions.get(name);
if (existing != null) {
int oldMask = existing.getMask();
int newMask = sp.getMask();
if (oldMask != newMask) {
permissions.put(name, new ServicePermission(name, oldMask
| newMask));
}
}
else {
permissions.put(name, permission);
}
if (!all_allowed) {
if (name.equals("*"))
all_allowed = true;
}
}
/**
* Determines if a set of permissions implies the permissions expressed in
* <code>permission</code>.
*
* @param permission The Permission object to compare.
*
* @return <code>true</code> if <code>permission</code> is a proper
* subset of a permission in the set; <code>false</code>
* otherwise.
*/
public boolean implies(Permission permission) {
if (!(permission instanceof ServicePermission))
return (false);
ServicePermission sp = (ServicePermission) permission;
ServicePermission x;
int desired = sp.getMask();
int effective = 0;
// short circuit if the "*" Permission was added
if (all_allowed) {
x = (ServicePermission) permissions.get("*");
if (x != null) {
effective |= x.getMask();
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.*
String name = sp.getName();
x = (ServicePermission) permissions.get(name);
if (x != null) {
// we have a direct hit!
effective |= x.getMask();
if ((effective & desired) == desired)
return (true);
}
// work our way up the tree...
int last, offset;
offset = name.length() - 1;
while ((last = name.lastIndexOf(".", offset)) != -1) {
name = name.substring(0, last + 1) + "*";
x = (ServicePermission) permissions.get(name);
if (x != null) {
effective |= x.getMask();
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 <code>ServicePermission</code>
* objects in the container.
*
* @return Enumeration of all the ServicePermission objects.
*/
public Enumeration<Permission> elements() {
return (permissions.elements());
}
}