iaik.pkcs.pkcs11.DefaultMutexHandler Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of sunpkcs11-wrapper Show documentation
PKCS#11 wrapper based on sunpkcs11
The newest version!
// Copyright (c) 2002 Graz University of Technology. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
//    this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. The end-user documentation included with the redistribution, if any, must
//    include the following acknowledgment:
//
//    "This product includes software developed by IAIK of Graz University of
//     Technology."
//
//    Alternately, this acknowledgment may appear in the software itself, if and
//    wherever such third-party acknowledgments normally appear.
//
// 4. The names "Graz University of Technology" and "IAIK of Graz University of
//    Technology" must not be used to endorse or promote products derived from
//    this software without prior written permission.
//
// 5. Products derived from this software may not be called "IAIK PKCS Wrapper",
//    nor may "IAIK" appear in their name, without prior written permission of
//    Graz University of Technology.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE LICENSOR BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
// OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

package iaik.pkcs.pkcs11;

import iaik.pkcs.pkcs11.wrapper.PKCS11Constants;
import sun.security.pkcs11.wrapper.PKCS11Exception;

/**
 * This class offers a default-implementation of a MutexHandler.
 *
 * @author Karl Scheibelhofer
 * @version 1.0
 */
public class DefaultMutexHandler implements MutexHandler {

  /**
   * A simple mutex implementation, but it satisfies the requirements stated
   * in PKCS#11 v2.11.
   *
   */
  private static class Mutex {

    /**
     * Indicates that this mutex is currently locked.
     */
    protected boolean locked;

    /**
     * Default constructor.
     */
    public Mutex() {
      locked = false;
    }

    /**
     * Locks this mutex. Waits until the mutex gets unlocked, if
     * it is already locked.
     *
     * @exception InterruptedException
     *              If the current thread has been interrupted.
     */
    public synchronized void lock() throws InterruptedException {
      if (Thread.interrupted()) {
        throw new InterruptedException();
      }
      try {
        while (locked) {
          wait();
        }
        locked = true;
      } catch (InterruptedException ex) {
        notify();
        throw ex;
      }
    }

    /**
     * Unlocks this mutex. It returns the previous lock-state.
     *
     * @return True, if the mutex was locked. False, otherwise.
     */
    public synchronized boolean unlock() {
      boolean previousState = locked;

      locked = false;
      notify();

      return previousState;
    }

    /**
     * Returns the string representation of this object.
     *
     * @return the string representation of this object
     */
    public String toString() {
      return ((locked) ? "locked" : "unlocked");
    }

  }

  /**
   * Create a new mutex object.
   *
   * @return The new mutex object.
   * @exception PKCS11Exception
   *              If the wrapper should return a different value than CKR_OK
   *              to the library. It gets the error-code and returns it as
   *              CK_RV.
   */
  @Override
  public Object createMutex() throws PKCS11Exception {
    return new Mutex();
  }

  /**
   * Destroy a mutex object.
   *
   * @param mutex
   *          The mutex object to destroy.
   * @exception PKCS11Exception
   *              If the wrapper should return a different value than CKR_OK
   *              to the library. It gets the error-code and returns it as
   *              CK_RV.
   */
  @Override
  public void destroyMutex(Object mutex) throws PKCS11Exception {
    // trust in the garbage collector
  }

  /**
   * If this method is called on with a mutex object which is not locked, the
   * calling thread obtains a lock on that mutex object and returns.
   * If this method is called with a mutex object which is locked by some
   * thread other than the calling thread, the calling thread blocks and waits
   * for that mutex to be unlocked.
   * If this method is called with a a mutex object which is locked by the
   * calling thread, the behavior of this method call is undefined.
   *
   * @param mutex
   *          The mutex object to lock.
   * @exception PKCS11Exception
   *              If the wrapper should return a different value than CKR_OK
   *              to the library. It gets the error-code and returns it as
   *              CK_RV.
   */
  @Override
  public void lockMutex(Object mutex) throws PKCS11Exception {
    if (!(mutex instanceof Mutex)) {
      throw new IllegalStateException("CKR_MUTEX_BAD: mutex is not instance of "
              + Mutex.class.getName());
    }

    Mutex castedMutex = (Mutex) mutex;
    while (true) {
      try {
        castedMutex.lock();
        break;
      } catch (InterruptedException ex) {
        // try again, until we succeed
      }
    }
  }

  /**
   * If this method is called with a mutex object which is locked by the
   * calling thread, that mutex object is unlocked and the function call
   * returns. Furthermore: If exactly one thread was blocking on that
   * particular mutex object, then that thread stops blocking, obtains a lock
   * on that mutex object, and its lockMutex(PKCS11Object) call returns.
   * If more than one thread was blocking on that particular mutex object,
   * then exactly one of the blocking threads is selected somehow. That lucky
   * thread stops blocking, obtains a lock on the mutex object, and its
   * lockMutex(PKCS11Object) call returns. All other threads blocking on that
   * particular mutex object continue to block.
   * If this method is called with a mutex object which is not locked, then
   * the method call throws an exception with the error code
   * PKCS11Constants.CKR_mutex_NOT_LOCKED.
   * If this method is called with a mutex object which is locked by some
   * thread other than the calling thread, the behavior of this method call is
   * undefined.
   *
   * @param mutex
   *          The mutex object to unlock.
   * @exception PKCS11Exception
   *              If the wrapper should return a different value than CKR_OK
   *              to the library. It gets the error-code and returns it as
   *              CK_RV.
   */
  @Override
  public void unlockMutex(Object mutex) throws PKCS11Exception {
    if (!(mutex instanceof Mutex)) {
      throw new IllegalStateException("CKR_MUTEX_BAD: mutex is not instance of "
              + Mutex.class.getName());
    }

    ((Mutex) mutex).unlock();
  }

}