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/* * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.security.pkcs11; import java.util.*; import java.security.ProviderException; import sun.security.util.Debug; import sun.security.pkcs11.wrapper.*;import static sun.security.pkcs11.wrapper.PKCS11Constants.*; /** * Session manager. There is one session manager object per PKCS#11 * provider. It allows code to checkout a session, release it * back to the pool, or force it to be closed. * * The session manager pools sessions to minimize the number of * C_OpenSession() and C_CloseSession() that have to be made. It * maintains two pools: one for "object" sessions and one for * "operation" sessions. * * The reason for this separation is how PKCS#11 deals with session objects. * It defines that when a session is closed, all objects created within * that session are destroyed. In other words, we may never close a session * while a Key created it in is still in use. We would like to keep the * number of such sessions low. Note that we occasionally want to explicitly * close a session, see P11Signature. * * NOTE that sessions obtained from this class SHOULD be returned using * either releaseSession() or closeSession() using a finally block when * not needed anymore. Otherwise, they will be left for cleanup via the * PhantomReference mechanism when GC kicks in, but it's best not to rely * on that since GC may not run timely enough since the native PKCS11 library * is also consuming memory. * * Note that sessions are automatically closed when they are not used for a * period of time, see Session. * * @author  Andreas Sterbenz * @since   1.5 */final class SessionManager {     private final static int DEFAULT_MAX_SESSIONS = 32;     private final static Debug debug = Debug.getInstance("pkcs11");     // token instance    private final Token token;     // maximum number of sessions to open with this token    private final int maxSessions;     // total number of active sessions    private int activeSessions;     // pool of available object sessions    private final Pool objSessions;     // pool of available operation sessions    private final Pool opSessions;     // maximum number of active sessions during this invocation, for debugging    private int maxActiveSessions;     // flags to use in the C_OpenSession() call    private final long openSessionFlags;     SessionManager(Token token) {        long n;        if (token.isWriteProtected()) {            openSessionFlags = CKF_SERIAL_SESSION;            n = token.tokenInfo.ulMaxSessionCount;        } else {            openSessionFlags = CKF_SERIAL_SESSION | CKF_RW_SESSION;            n = token.tokenInfo.ulMaxRwSessionCount;        }        if (n == CK_EFFECTIVELY_INFINITE) {            n = Integer.MAX_VALUE;        } else if ((n == CK_UNAVAILABLE_INFORMATION) || (n < 0)) {            // choose an arbitrary concrete value            n = DEFAULT_MAX_SESSIONS;        }        maxSessions = (int)Math.min(n, Integer.MAX_VALUE);        this.token = token;        this.objSessions = new Pool(this);        this.opSessions = new Pool(this);    }     // returns whether only a fairly low number of sessions are    // supported by this token.    boolean lowMaxSessions() {        return (maxSessions <= DEFAULT_MAX_SESSIONS);    }     synchronized Session getObjSession() throws PKCS11Exception {        Session session = objSessions.poll();        if (session != null) {            return ensureValid(session);        }        session = opSessions.poll();        if (session != null) {            return ensureValid(session);        }        session = openSession();        return ensureValid(session);    }     synchronized Session getOpSession() throws PKCS11Exception {        Session session = opSessions.poll();        if (session != null) {            return ensureValid(session);        }        // create a new session rather than re-using an obj session        // that avoids potential expensive cancels() for Signatures & RSACipher        if (maxSessions == Integer.MAX_VALUE ||                activeSessions < maxSessions) {            session = openSession();            return ensureValid(session);        }        session = objSessions.poll();        if (session != null) {            return ensureValid(session);        }        throw new ProviderException("Could not obtain session");    }     private Session ensureValid(Session session) {        session.id();        return session;    }     synchronized Session killSession(Session session) {        if ((session == null) || (token.isValid() == false)) {            return null;        }        if (debug != null) {            String location = new Exception().getStackTrace()[2].toString();            System.out.println("Killing session (" + location + ") active: "                + activeSessions);        }        closeSession(session);        return null;    }     synchronized Session releaseSession(Session session) {        if ((session == null) || (token.isValid() == false)) {            return null;        }         if (session.hasObjects()) {            objSessions.release(session);        } else {            opSessions.release(session);        }        return null;    }     synchronized void demoteObjSession(Session session) {        if (token.isValid() == false) {            return;        }        if (debug != null) {            System.out.println("Demoting session, active: " +                activeSessions);        }        boolean present = objSessions.remove(session);        if (present == false) {            // session is currently in use            // will be added to correct pool on release, nothing to do now            return;        }        opSessions.release(session);    }     private Session openSession() throws PKCS11Exception {        if ((maxSessions != Integer.MAX_VALUE) &&                (activeSessions >= maxSessions)) {            throw new ProviderException("No more sessions available");        }        long id = token.p11.C_OpenSession                    (token.provider.slotID, openSessionFlags, null, null);        Session session = new Session(token, id);        activeSessions++;        if (debug != null) {            if (activeSessions > maxActiveSessions) {                maxActiveSessions = activeSessions;                if (maxActiveSessions % 10 == 0) {                    System.out.println("Open sessions: " + maxActiveSessions);                }            }        }        return session;    }     private void closeSession(Session session) {        session.close();        activeSessions--;    }     private static final class Pool {         private final SessionManager mgr;         private final List<Session> pool;         Pool(SessionManager mgr) {            this.mgr = mgr;            pool = new ArrayList<Session>();        }         boolean remove(Session session) {            return pool.remove(session);        }         Session poll() {            int n = pool.size();            if (n == 0) {                return null;            }            Session session = pool.remove(n - 1);            return session;        }         void release(Session session) {            pool.add(session);            // if there are idle sessions, close them            if (session.hasObjects()) {                return;            }            int n = pool.size();            if (n < 5) {                return;            }            Session oldestSession = pool.get(0);            long time = System.currentTimeMillis();            if (session.isLive(time) && oldestSession.isLive(time)) {                return;            }            Collections.sort(pool);            int i = 0;            while (i < n - 1) { // always keep at least 1 session open                oldestSession = pool.get(i);                if (oldestSession.isLive(time)) {                    break;                }                i++;                mgr.closeSession(oldestSession);            }            if (debug != null) {                System.out.println("Closing " + i + " idle sessions, active: "                        + mgr.activeSessions);            }            List<Session> subList = pool.subList(0, i);            subList.clear();        }     } }