001/* MBeanPermission.java -- Permissions controlling server access.
002   Copyright (C) 2006 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package javax.management;
039
040import gnu.java.lang.CPStringBuilder;
041
042import java.security.Permission;
043
044import java.io.IOException;
045import java.io.ObjectInputStream;
046
047import java.util.HashSet;
048import java.util.Iterator;
049import java.util.Set;
050import java.util.TreeSet;
051
052/**
053 * <p>
054 * Represents the permissions required to perform
055 * operations using the {@link MBeanServer}.  As with
056 * all {@link java.security.Permission} objects, an
057 * instance of this class either represents a permission
058 * already held or one that is required to access a
059 * particular service.  In the case of {@link MBeanPermission}s,
060 * implication checks are made using an instance of this class
061 * when a user requests an operation from the server, and a
062 * {@link SecurityManager} is in place.
063 * </p>
064 * <p>
065 * An {@link MBeanPermission} consists of four elements,
066 * which all have to match for the permission to be implied.
067 * These are as follows:
068 * </p>
069 * <ol>
070 * <li><strong>The action</strong>.  For a required permission,
071 * this is a single value.  For a permission held by the user,
072 * this is a list of comma-separated actions (with spaces allowed),
073 * or <code>*</code> (representing all actions).  {@link #getActions()}
074 * returns this value.</li>
075 * <li><strong>The class name</strong>.  For a required permission,
076 * this is the class name of the bean being accessed, if any.  If
077 * a bean isn't involved in this action, the value is <code>null</code>.
078 * For a permission held by the user, it has one of three values:
079 * <ol>
080 * <li>The empty string, implying any class.</li>
081 * <li><code>*</code>, also implying any class.</li>
082 * <li>A class name pattern, which may specify a single class
083 * (e.g. <code>java.lang.Object</code>) or a series of classes
084 * using the wildcard character <code>*</code> (e.g.
085 * <code>javax.swing.*</code>.)</li>
086 * </ol></li>
087 * <li><strong>The member</strong>.  For a required permission,
088 * this is the member of the bean being accessed (an attribute
089 * or operation), if any.  If a member of the bean isn't involved
090 * in this action, the value is <code>null</code>.
091 * For a permission held by the user, it has one of three values:
092 * <ol>
093 * <li>The empty string, implying any member.</li>
094 * <li><code>*</code>, also implying any member.</li>
095 * <li>The name of a member.</li>
096 * </ol></li>
097 * <li>The object name</strong>.  For a required permission,
098 * this is the {@link ObjectName} of the bean being accessed, if
099 * any.  If a bean isn't involved in this action, the value is
100 * <code>null</code>.  The name may not be a pattern.
101 * For a permission held by the user, it may be the empty
102 * string (allowing everything) or an {@link ObjectName}
103 * pattern.
104 * </li></ol>
105 * {@link #getName()} returns the latter three of these as a
106 * single string:
107 * </p>
108 * <p><code>className#member[objectName]</code></p>
109 * <p>
110 * where <code>""</code> is disallowed, as, although any of
111 * the elements may be omitted, not all of them should be
112 * left out simultaneously.  <code>"-"</code> is used to
113 * represent <code>null</code>.  When this occurs in a
114 * required permission, anything may match it.  When this
115 * forms part of a permission held by the user, it only
116 * matches another <code>null</code> value.
117 * </p>
118 * <p>The list of valid actions is as follows:</p>
119 * <ul>
120 * <li>addNotificationListener</li>
121 * <li>getAttribute</li>
122 * <li>getClassLoader</li>
123 * <li>getClassLoaderFor</li>
124 * <li>getClassLoaderRepository</li>
125 * <li>getDomains</li>
126 * <li>getMBeanInfo</li>
127 * <li>getObjectInstance</li>
128 * <li>instantiate</li>
129 * <li>invoke</li>
130 * <li>isInstanceOf</li>
131 * <li>queryMBeans</li>
132 * <li>queryNames</li>
133 * <li>registerMBean</li>
134 * <li>removeNotificationListener</li>
135 * <li>setAttribute</li>
136 * <li>unregisterMBean</li>
137 * </ul>
138 *
139 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
140 * @since 1.5
141 */
142public class MBeanPermission
143  extends Permission
144{
145
146  /**
147   * Compatible with JDK 1.5
148   */
149  private static final long serialVersionUID = -2416928705275160661L;
150
151  /**
152   * The list of actions associated with this permission.
153   */
154  private String actions;
155
156  /**
157   * The list of actions as an ordered set.
158   */
159  private transient Set<String> actionSet;
160
161  /**
162   * The set of valid actions.
163   */
164  private static final Set<String> validSet;
165
166  /**
167   * Initialise the set of valid actions.
168   */
169  static
170  {
171    validSet = new HashSet<String>();
172    validSet.add("addNotificationListener");
173    validSet.add("getAttribute");
174    validSet.add("getClassLoader");
175    validSet.add("getClassLoaderFor");
176    validSet.add("getClassLoaderRepository");
177    validSet.add("getDomains");
178    validSet.add("getMBeanInfo");
179    validSet.add("getObjectInstance");
180    validSet.add("instantiate");
181    validSet.add("invoke");
182    validSet.add("isInstanceOf");
183    validSet.add("queryMBeans");
184    validSet.add("queryNames");
185    validSet.add("registerMBean");
186    validSet.add("removeNotificationListener");
187    validSet.add("setAttribute");
188    validSet.add("unregisterMBean");
189  }
190
191  /**
192   * Constructs a new {@link MBeanPermission} with the specified name
193   * and actions.  The name is of the form <code>className#member[objectName]</code>,
194   * where each element is optional, but a completely empty or <code>null</code>
195   * name is disallowed.  Actions are specified as a comma-separated list
196   * and may also not be empty or <code>null</code>.
197   *
198   * @param name the name of the permission.
199   * @param actions the actions associated with this permission.
200   * @throws IllegalArgumentException if the name or actions are invalid.
201   */
202  public MBeanPermission(String name, String actions)
203  {
204    super(name);
205    if (name == null || name.length() == 0)
206      throw new IllegalArgumentException("The supplied name was null or empty.");
207    if (actions == null || actions.length() == 0)
208      throw new IllegalArgumentException("The supplied action list was null or empty.");
209    this.actions = actions;
210    updateActionSet();
211  }
212
213  /**
214   * Constructs a new {@link MBeanPermission} with the specified class name,
215   * member, object name and actions.  The name of the permission is created
216   * using the form <code>className#member[objectName]</code>,
217   * where each element is optional, but an empty or <code>null</code>
218   * name is disallowed.  Actions are specified as a comma-separated list
219   * and may also not be empty or <code>null</code>.
220   *
221   * @param className the name of the class to which this permission applies,
222   *                  or either <code>null</code> or <code>"-"</code> for a
223   *                  value which may be implied by any class name, but not
224   *                  imply any class name itself.
225   * @param member the member of the class to which this permission applies,
226   *               or either <code>null</code> or <code>"-"</code> for a
227   *               value which may be implied by any member, but not
228   *               imply any member itself.
229   * @param name the {@link ObjectName} to which this permission applies,
230   *                  or <code>null</code> for a value which may be implied by
231   *                  any object name, but not imply any object name itself.
232   * @param actions the actions associated with this permission.
233   */
234  public MBeanPermission(String className, String member,
235                         ObjectName name, String actions)
236  {
237    this((className == null ? "-" : className) + "#"
238         + (member == null ? "-" : member) + "["
239         + (name == null ? "-" : name.toString()) + "]", actions);
240  }
241
242  /**
243   * Returns true if the given object is also an {@link MBeanPermission}
244   * with the same name and actions.
245   *
246   * @param obj the object to test.
247   * @return true if the object is an {@link MBeanPermission} with
248   *         the same name and actions.
249   */
250  public boolean equals(Object obj)
251  {
252    if (obj instanceof MBeanPermission)
253      {
254        MBeanPermission p = (MBeanPermission) obj;
255        return (p.getName().equals(getName()) &&
256                p.getActions().equals(actions));
257      }
258    return false;
259  }
260
261  /**
262   * Returns the list of actions in alphabetical order.
263   *
264   * @return the list of actions.
265   */
266  public String getActions()
267  {
268    Iterator<String> it = actionSet.iterator();
269    CPStringBuilder builder = new CPStringBuilder();
270    while (it.hasNext())
271      {
272        builder.append(it.next());
273        if (it.hasNext())
274          builder.append(",");
275      }
276    return builder.toString();
277  }
278
279  /**
280   * Returns the hashcode of the permission as the sum
281   * of the hashcodes of the name and actions.
282   *
283   * @return the hashcode of the permission.
284   */
285  public int hashCode()
286  {
287    return getName().hashCode() + actions.hashCode();
288  }
289
290  /**
291   * <p>
292   * Returns true if this permission implies the supplied permission.
293   * This happens if the following holds:
294   * </p>
295   * <ul>
296   * <li>The supplied permission is an {@link MBeanPermission}</li>
297   * <li>The supplied permission has either a <code>null</code> classname
298   * or its classname matches the classname of this permission.  A
299   * classname of <code>"*"</code> for this permission always matches
300   * the classname of the supplied permission.  Generally, <code>'*'</code>
301   * acts as a wildcard, so <code>".*"</code> matches <code>'.'</code>
302   * followed by anything.</li>
303   * <li>The supplied permission has either a <code>null</code> member
304   * or its member matches the member of this permission.  A member of
305   * <code>"*"</code> for this permission always matches the member
306   * of the supplied permission.</li>
307   * <li>The supplied permission has either a <code>null</code> object name
308   * or its object name matches the object name of this permission.  If the
309   * object name of this permission is a pattern, {@link ObjectName#apply(ObjectName)}
310   * may be used as well.</li>
311   * <li>The supplied permission's actions are a subset of the actions
312   * of this permission.  If the <code>queryMBeans</code> action is presented,
313   * the <code>queryNames</code> action is implied.</li>
314   * </ul>
315   *
316   * @param p the permission to check that this permission implies.
317   * @return true if this permission implies <code>p</code>.
318   */
319  public boolean implies(Permission p)
320  {
321    if (p instanceof MBeanPermission)
322      {
323        MBeanPermission mp = (MBeanPermission) p;
324        NameHolder pName = new NameHolder(mp.getName());
325        NameHolder name = new NameHolder(getName());
326        if (!(name.equals(pName)))
327          return false;
328        for (String nextAction : mp.actionSet)
329          {
330            boolean found = actions.contains(nextAction);
331            if (!found)
332              if (nextAction.equals("queryNames"))
333                found = actions.contains("queryMBeans");
334            if (!found)
335              return false;
336          }
337        return true;
338      }
339    return false;
340  }
341
342  /**
343   * Small helper class to handle deconstruction of the name.
344   *
345   * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
346   */
347  private class NameHolder
348  {
349
350    /**
351     * The class name.
352     */
353    private String className;
354
355    /**
356     * The member.
357     */
358    private String member;
359
360    /**
361     * The object name.
362     */
363    private ObjectName objectName;
364
365    /**
366     * Constructs a broken-down name from a given name.
367     *
368     * @param name the name to break down.
369     */
370    public NameHolder(String name)
371    {
372      String objectName = null;
373      int memberIndex = name.indexOf("#");
374      int onIndex = name.indexOf("[");
375      if (onIndex == -1)
376        {
377          if (memberIndex == -1)
378            className = name;
379          else
380            {
381              className = name.substring(0, memberIndex);
382              member = name.substring(memberIndex + 1);
383            }
384        }
385      else
386        {
387          if (memberIndex == -1)
388            {
389              className = name.substring(0, onIndex);
390              objectName = name.substring(onIndex + 1,
391                                          name.length() - 1);
392            }
393          else
394            {
395              className = name.substring(0, memberIndex);
396              member = name.substring(memberIndex + 1, onIndex);
397              objectName = name.substring(onIndex + 1,
398                                          name.length() - 1);
399            }
400        }
401      if (className.equals("-"))
402        className = null;
403      if (member.equals("-"))
404        member = null;
405      if (objectName == null || objectName.equals("-"))
406        this.objectName = null;
407      else
408        try
409          {
410            this.objectName = new ObjectName(objectName);
411          }
412        catch (MalformedObjectNameException e)
413          {
414            throw (Error)
415              (new InternalError("Invalid object name.").initCause(e));
416          }
417    }
418
419    /**
420     * <p>
421     * Returns true if the supplied object is also a
422     * {@link NameHolder} and the following holds:
423     * </p>
424     * <ul>
425     * <li>The supplied classname is <code>null</code> or the two match.  A
426     * classname of <code>"*"</code> for this holder always matches
427     * the classname of the supplied holder.  Generally, <code>'*'</code>
428     * acts as a wildcard, so <code>".*"</code> matches <code>'.'</code>
429     * followed by anything.</li>
430     * <li>The supplied name holder has either a <code>null</code> member
431     * or its member matches the member of this name holder.  A member of
432     * <code>"*"</code> for this name holder always matches the member
433     * of the supplied name holder.</li>
434     * <li>The supplied name holder has either a <code>null</code> object name
435     * or its object name matches the object name of this name holder.  If the
436     * object name of this name holder is a pattern,
437     * {@link ObjectName#apply(ObjectName)} may be used as well.</li>
438     * </ul>
439     *
440     * @param obj the object to compare with this.
441     * @return true if the above holds.
442     */
443    public boolean equals(Object obj)
444    {
445      if (obj instanceof NameHolder)
446        {
447          NameHolder nh = (NameHolder) obj;
448          boolean cn = false;
449          String ocn = nh.getClassName();
450          if (ocn == null || className.equals("*"))
451            cn = true;
452          else
453            {
454              int wcIndex = className.indexOf("*");
455              if (wcIndex != -1)
456                cn = ocn.startsWith(className.substring(0, wcIndex));
457              else
458                cn = ocn.equals(className);
459            }
460          boolean m = false;
461          String om = nh.getMember();
462          if (om == null || member.equals("*"))
463            m = true;
464          else
465            m = om.equals(member);
466          boolean on = false;
467          ObjectName oon = nh.getObjectName();
468          if (oon == null)
469            on = true;
470          else if (objectName.isPattern())
471            on = objectName.apply(oon);
472          else
473            on = oon.equals(objectName);
474          return (cn && m && on);
475        }
476      return false;
477    }
478
479    /**
480     * Returns the class name.
481     */
482    public String getClassName()
483    {
484      return className;
485    }
486
487    /**
488     * Returns the member.
489     */
490    public String getMember()
491    {
492      return member;
493    }
494
495    /**
496     * Returns the object name.
497     */
498    public ObjectName getObjectName()
499    {
500      return objectName;
501    }
502  }
503
504  /**
505   * Updates the action set from the current value of
506   * the actions string.
507   */
508  private void updateActionSet()
509  {
510    String[] actionsArray = actions.split(",");
511    actionSet = new TreeSet<String>();
512    for (int a = 0; a < actionsArray.length; ++a)
513      actionSet.add(actionsArray[a].trim());
514  }
515
516  /**
517   * Reads the object from a stream and ensures the incoming
518   * data is valid.
519   *
520   * @param in the input stream.
521   * @throws IOException if an I/O error occurs.
522   * @throws ClassNotFoundException if a class used by the object
523   *                                can not be found.
524   */
525  private void readObject(ObjectInputStream in)
526    throws IOException, ClassNotFoundException
527  {
528    in.defaultReadObject();
529    updateActionSet();
530    checkActions();
531  }
532
533  /**
534   * Checks that the actions used in this permission
535   * are from the valid set.
536   *
537   * @throws IllegalArgumentException if the name or actions are invalid.
538   */
539  private void checkActions()
540  {
541    for (String action : actionSet)
542      {
543        if (!(validSet.contains(action)))
544          throw new IllegalArgumentException("Invalid action "
545                                             + action + " found.");
546      }
547  }
548
549}