Package org.osgi.framework

Source Code of org.osgi.framework.PackagePermissionCollection

/*
* 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.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.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;

/**
* A bundle's authority to import or export a package.
*
* <p>
* A package is a dot-separated string that defines a fully qualified Java
* package.
* <p>
* For example:
*
* <pre>
* org.osgi.service.http
* </pre>
*
* <p>
* {@code PackagePermission} has three actions: {@code exportonly},
* {@code import} and {@code export}. The {@code export} action, which is
* deprecated, implies the {@code import} action.
*
* @ThreadSafe
* @author $Id: c2d45ff158a6a19ff7bc155af3ac9941cb6a89d6 $
*/

public final class PackagePermission extends BasicPermission {
  static final long                serialVersionUID  = -5107705877071099135L;

  /**
   * The action string {@code export}. The {@code export} action implies the
   * {@code import} action.
   *
   * @deprecated Since 1.5. Use {@code exportonly} instead.
   */
  public final static String            EXPORT        = "export";

  /**
   * The action string {@code exportonly}. The {@code exportonly} action does
   * not imply the {@code import} action.
   *
   * @since 1.5
   */
  public final static String            EXPORTONLY      = "exportonly";

  /**
   * The action string {@code import}.
   */
  public final static String            IMPORT        = "import";

  private final static int            ACTION_EXPORT    = 0x00000001;
  private final static int            ACTION_IMPORT    = 0x00000002;
  private final static int            ACTION_ALL      = ACTION_EXPORT | ACTION_IMPORT;
  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 bundle used by this PackagePermission.
   */
  transient final Bundle              bundle;

  /**
   * If this PackagePermission was constructed with a filter, this holds a
   * Filter matching object used to evaluate the filter in implies.
   */
  transient Filter                filter;

  /**
   * 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<String, Object>  properties;

  /**
   * Creates a new {@code PackagePermission} object.
   *
   * <p>
   * The name is specified as a normal Java package name: a dot-separated
   * string. Wildcards may be used.
   *
   * <pre>
   * name ::= &lt;package name&gt; | &lt;package name ending in &quot;.*&quot;&gt; | *
   * </pre>
   *
   * Examples:
   *
   * <pre>
   * org.osgi.service.http
   * javax.servlet.*
   * *
   * </pre>
   *
   * For the {@code import} action, the name can also be a filter expression.
   * The filter gives access to the following attributes:
   * <ul>
   * <li>signer - A Distinguished Name chain used to sign the exporting
   * bundle. Wildcards in a DN are not matched according to the filter string
   * rules, but according to the rules defined for a DN chain.</li>
   * <li>location - The location of the exporting bundle.</li>
   * <li>id - The bundle ID of the exporting bundle.</li>
   * <li>name - The symbolic name of the exporting bundle.</li>
   * <li>package.name - The name of the requested package.</li>
   * </ul>
   * Filter attribute names are processed in a case sensitive manner.
   *
   * <p>
   * Package Permissions are granted over all possible versions of a package.
   *
   * A bundle that needs to export a package must have the appropriate
   * {@code PackagePermission} for that package; similarly, a bundle that
   * needs to import a package must have the appropriate
   * {@code PackagePermssion} for that package.
   * <p>
   * Permission is granted for both classes and resources.
   *
   * @param name Package name or filter expression. A filter expression can
   *        only be specified if the specified action is {@code import}.
   * @param actions {@code exportonly},{@code import} (canonical order).
   * @throws IllegalArgumentException If the specified name is a filter
   *         expression and either the specified action is not {@code import}
   *         or the filter has an invalid syntax.
   */
  public PackagePermission(String name, String actions) {
    this(name, parseActions(actions));
    if ((filter != null) && ((action_mask & ACTION_ALL) != ACTION_IMPORT)) {
      throw new IllegalArgumentException("invalid action string for filter expression");
    }
  }

  /**
   * Creates a new requested {@code PackagePermission} object to be used by
   * code that must perform {@code checkPermission} for the {@code import}
   * action. {@code PackagePermission} objects created with this constructor
   * cannot be added to a {@code PackagePermission} permission collection.
   *
   * @param name The name of the requested package to import.
   * @param exportingBundle The bundle exporting the requested package.
   * @param actions The action {@code import}.
   * @throws IllegalArgumentException If the specified action is not
   *         {@code import} or the name is a filter expression.
   * @since 1.5
   */
  public PackagePermission(String name, Bundle exportingBundle, String actions) {
    super(name);
    setTransients(name, parseActions(actions));
    this.bundle = exportingBundle;
    if (exportingBundle == null) {
      throw new IllegalArgumentException("bundle must not be null");
    }
    if (filter != null) {
      throw new IllegalArgumentException("invalid name");
    }
    if ((action_mask & ACTION_ALL) != ACTION_IMPORT) {
      throw new IllegalArgumentException("invalid action string");
    }
  }

  /**
   * Package private constructor used by PackagePermissionCollection.
   *
   * @param name package name
   * @param mask action mask
   */
  PackagePermission(String name, int mask) {
    super(name);
    setTransients(name, mask);
    this.bundle = null;
  }

  /**
   * Called by constructors and when deserialized.
   *
   * @param mask action mask
   */
  private void setTransients(String name, int mask) {
    if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) {
      throw new IllegalArgumentException("invalid action string");
    }
    action_mask = mask;
    filter = parseFilter(name);
  }

  /**
   * 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 >= 5 && (a[i - 5] == 'i' || a[i - 5] == 'I')
          && (a[i - 4] == 'm' || a[i - 4] == 'M')
          && (a[i - 3] == 'p' || a[i - 3] == 'P')
          && (a[i - 2] == 'o' || a[i - 2] == 'O')
          && (a[i - 1] == 'r' || a[i - 1] == 'R')
          && (a[i] == 't' || a[i] == 'T')) {
        matchlen = 6;
        mask |= ACTION_IMPORT;

      } else
        if (i >= 5 && (a[i - 5] == 'e' || a[i - 5] == 'E')
            && (a[i - 4] == 'x' || a[i - 4] == 'X')
            && (a[i - 3] == 'p' || a[i - 3] == 'P')
            && (a[i - 2] == 'o' || a[i - 2] == 'O')
            && (a[i - 1] == 'r' || a[i - 1] == 'R')
            && (a[i] == 't' || a[i] == 'T')) {
          matchlen = 6;
          mask |= ACTION_EXPORT | ACTION_IMPORT;

        } else {
          if (i >= 9 && (a[i - 9] == 'e' || a[i - 9] == 'E')
              && (a[i - 8] == 'x' || a[i - 8] == 'X')
              && (a[i - 7] == 'p' || a[i - 7] == 'P')
              && (a[i - 6] == 'o' || a[i - 6] == 'O')
              && (a[i - 5] == 'r' || a[i - 5] == 'R')
              && (a[i - 4] == 't' || a[i - 4] == 'T')
              && (a[i - 3] == 'o' || a[i - 3] == 'O')
              && (a[i - 2] == 'n' || a[i - 2] == 'N')
              && (a[i - 1] == 'l' || a[i - 1] == 'L')
              && (a[i] == 'y' || a[i] == 'Y')) {
            matchlen = 10;
            mask |= ACTION_EXPORT;

          } else {
            // parse error
            throw new IllegalArgumentException("invalid permission: " + actions);
          }
        }

      // make sure we didn't just match the tail of a word
      // like "ackbarfimport". 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 {@code 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 the specified permission is implied by this object.
   *
   * <p>
   * This method checks that the package name of the target is implied by the
   * package name of this object. The list of {@code PackagePermission}
   * actions must either match or allow for the list of the target object to
   * imply the target {@code PackagePermission} action.
   * <p>
   * The permission to export a package implies the permission to import the
   * named package.
   *
   * <pre>
   * x.y.*,&quot;export&quot; -&gt; x.y.z,&quot;export&quot; is true
   * *,&quot;import&quot; -&gt; x.y, &quot;import&quot;      is true
   * *,&quot;export&quot; -&gt; x.y, &quot;import&quot;      is true
   * x.y,&quot;export&quot; -&gt; x.y.z, &quot;export&quot;  is false
   * </pre>
   *
   * @param p The requested permission.
   * @return {@code true} if the specified permission is implied by this
   *         object; {@code false} otherwise.
   */
  @Override
  public boolean implies(Permission p) {
    if (!(p instanceof PackagePermission)) {
      return false;
    }
    PackagePermission requested = (PackagePermission) p;
    if (bundle != 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 PackagePermission which has already be
   *        validated as a proper argument. The requested PackagePermission
   *        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(PackagePermission requested, int effective) {
    /* check actions first - much faster */
    effective |= action_mask;
    final int desired = requested.action_mask;
    if ((effective & desired) != desired) {
      return false;
    }
    /* Get filter if any */
    Filter f = filter;
    if (f == null) {
      return super.implies(requested);
    }
    return f.matches(requested.getProperties());
  }

  /**
   * Returns the canonical string representation of the
   * {@code PackagePermission} actions.
   *
   * <p>
   * Always returns present {@code PackagePermission} actions in the following
   * order: {@code EXPORTONLY},{@code IMPORT}.
   *
   * @return Canonical string representation of the {@code PackagePermission}
   *         actions.
   */
  @Override
  public String getActions() {
    String result = actions;
    if (result == null) {
      StringBuffer sb = new StringBuffer();
      boolean comma = false;

      int mask = action_mask;
      if ((mask & ACTION_EXPORT) == ACTION_EXPORT) {
        sb.append(EXPORTONLY);
        comma = true;
      }

      if ((mask & ACTION_IMPORT) == ACTION_IMPORT) {
        if (comma)
          sb.append(',');
        sb.append(IMPORT);
      }

      actions = result = sb.toString();
    }
    return result;
  }

  /**
   * Returns a new {@code PermissionCollection} object suitable for storing
   * {@code PackagePermission} objects.
   *
   * @return A new {@code PermissionCollection} object.
   */
  @Override
  public PermissionCollection newPermissionCollection() {
    return new PackagePermissionCollection();
  }

  /**
   * Determines the equality of two {@code PackagePermission} objects.
   *
   * This method checks that specified package has the same package name and
   * {@code PackagePermission} actions as this {@code PackagePermission}
   * object.
   *
   * @param obj The object to test for equality with this
   *        {@code PackagePermission} object.
   * @return {@code true} if {@code obj} is a {@code PackagePermission}, and
   *         has the same package name and actions as this
   *         {@code PackagePermission} object; {@code false} otherwise.
   */
  @Override
  public boolean equals(Object obj) {
    if (obj == this) {
      return true;
    }

    if (!(obj instanceof PackagePermission)) {
      return false;
    }

    PackagePermission pp = (PackagePermission) obj;

    return (action_mask == pp.action_mask) && getName().equals(pp.getName()) && ((bundle == pp.bundle) || ((bundle != null) && bundle.equals(pp.bundle)));
  }

  /**
   * Returns the hash code value for this object.
   *
   * @return A hash code value for this object.
   */
  @Override
  public int hashCode() {
    int h = 31 * 17 + getName().hashCode();
    h = 31 * h + getActions().hashCode();
    if (bundle != null) {
      h = 31 * h + bundle.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 (bundle != 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(getName(), parseActions(actions));
  }

  /**
   * Called by {@link PackagePermission#implies(Permission)}. This method is
   * only called on a requested permission which cannot have a filter set.
   *
   * @return a map of properties for this permission.
   */
  private Map<String, Object> getProperties() {
    Map<String, Object> result = properties;
    if (result != null) {
      return result;
    }
    final Map<String, Object> map = new HashMap<String, Object>(5);
    map.put("package.name", getName());
    if (bundle != null) {
      AccessController.doPrivileged(new PrivilegedAction<Void>() {
        public Void run() {
          map.put("id", new Long(bundle.getBundleId()));
          map.put("location", bundle.getLocation());
          String name = bundle.getSymbolicName();
          if (name != null) {
            map.put("name", name);
          }
          SignerProperty signer = new SignerProperty(bundle);
          if (signer.isBundleSigned()) {
            map.put("signer", signer);
          }
          return null;
        }
      });
    }
    return properties = map;
  }
}

/**
* Stores a set of {@code PackagePermission} permissions.
*
* @see java.security.Permission
* @see java.security.Permissions
* @see java.security.PermissionCollection
*/

final class PackagePermissionCollection extends PermissionCollection {
  static final long                  serialVersionUID  = -3350758995234427603L;
  /**
   * Table of permissions with names.
   *
   * @GuardedBy this
   */
  private transient Map<String, PackagePermission>  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<String, PackagePermission>        filterPermissions;

  /**
   * Create an empty PackagePermissions object.
   */
  public PackagePermissionCollection() {
    permissions = new HashMap<String, PackagePermission>();
    all_allowed = false;
  }

  /**
   * Adds a permission to this permission collection.
   *
   * @param permission The {@code PackagePermission} object to add.
   * @throws IllegalArgumentException If the specified permission is not a
   *         {@code PackagePermission} instance or was constructed with a
   *         Bundle object.
   * @throws SecurityException If this {@code PackagePermissionCollection}
   *         object has been marked read-only.
   */
  @Override
  public void add(final Permission permission) {
    if (!(permission instanceof PackagePermission)) {
      throw new IllegalArgumentException("invalid permission: " + permission);
    }
    if (isReadOnly()) {
      throw new SecurityException("attempt to add a Permission to a " + "readonly PermissionCollection");
    }

    final PackagePermission pp = (PackagePermission) permission;
    if (pp.bundle != null) {
      throw new IllegalArgumentException("cannot add to collection: " + pp);
    }

    final String name = pp.getName();
    final Filter f = pp.filter;
    synchronized (this) {
      /* select the bucket for the permission */
      Map<String, PackagePermission> pc;
      if (f != null) {
        pc = filterPermissions;
        if (pc == null) {
          filterPermissions = pc = new HashMap<String, PackagePermission>();
        }
      } else {
        pc = permissions;
      }

      final PackagePermission existing = pc.get(name);
      if (existing != null) {
        final int oldMask = existing.action_mask;
        final int newMask = pp.action_mask;
        if (oldMask != newMask) {
          pc.put(name, new PackagePermission(name, oldMask | newMask));

        }
      } else {
        pc.put(name, pp);
      }

      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 this
   *        {@code PackagePermission} object.
   * @return {@code true} if {@code permission} is a proper subset of a
   *         permission in the set; {@code false} otherwise.
   */
  @Override
  public boolean implies(final Permission permission) {
    if (!(permission instanceof PackagePermission)) {
      return false;
    }
    final PackagePermission requested = (PackagePermission) permission;
    /* if requested permission has a filter, then it is an invalid argument */
    if (requested.filter != null) {
      return false;
    }
    String requestedName = requested.getName();
    final int desired = requested.action_mask;
    int effective = PackagePermission.ACTION_NONE;

    Collection<PackagePermission> perms;
    synchronized (this) {
      Map<String, PackagePermission> pc = permissions;
      PackagePermission pp;
      /* short circuit if the "*" Permission was added */
      if (all_allowed) {
        pp = pc.get("*");
        if (pp != null) {
          effective |= pp.action_mask;
          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.*
       */
      pp = pc.get(requestedName);
      if (pp != null) {
        /* we have a direct hit! */
        effective |= pp.action_mask;
        if ((effective & desired) == desired) {
          return true;
        }
      }
      /* 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) + "*";
        pp = pc.get(requestedName);
        if (pp != null) {
          effective |= pp.action_mask;
          if ((effective & desired) == desired) {
            return true;
          }
        }
        offset = last - 1;
      }
      /*
       * we don't have to check for "*" as it was already checked before
       * we were called.
       */
      pc = filterPermissions;
      if (pc == null) {
        return false;
      }
      perms = pc.values();
    }
    /* iterate one by one over filteredPermissions */
    for (PackagePermission perm : perms) {
      if (perm.implies0(requested, effective)) {
        return true;
      }
    }
    return false;
  }

  /**
   * Returns an enumeration of all {@code PackagePermission} objects in the
   * container.
   *
   * @return Enumeration of all {@code PackagePermission} objects.
   */
  @Override
  public synchronized Enumeration<Permission> elements() {
    List<Permission> all = new ArrayList<Permission>(permissions.values());
    Map<String, PackagePermission> 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<String, PackagePermission> hashtable = new Hashtable<String, PackagePermission>(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();
    @SuppressWarnings("unchecked")
    Hashtable<String, PackagePermission> hashtable = (Hashtable<String, PackagePermission>) gfields.get("permissions", null);
    permissions = new HashMap<String, PackagePermission>(hashtable);
    all_allowed = gfields.get("all_allowed", false);
    @SuppressWarnings("unchecked")
    HashMap<String, PackagePermission> fp = (HashMap<String, PackagePermission>) gfields.get("filterPermissions", null);
    filterPermissions = fp;
  }
}
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