/*

 * Copyright 2003-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.pkcs11;

import java.util.*;

import java.io.*;

import java.lang.ref.*;

import java.security.*;

import javax.security.auth.login.LoginException;

import sun.security.jca.JCAUtil;

import sun.security.pkcs11.wrapper.*;

import static sun.security.pkcs11.wrapper.PKCS11Constants.*;

/**

 * PKCS#11 token.

 *

 * @author  Andreas Sterbenz

 * @since   1.5

 */

class Token implements Serializable {

    // need to be serializable to allow SecureRandom to be serialized

    private static final long serialVersionUID = 2541527649100571747L;

    // how often to check if the token is still present (in ms)

    // this is different from checking if a token has been inserted,

    // that is done in SunPKCS11. Currently 50 ms.

    private final static long CHECK_INTERVAL = 50;

    final SunPKCS11 provider;

    final PKCS11 p11;

    final Config config;

    final CK_TOKEN_INFO tokenInfo;

    // session manager to pool sessions

    final SessionManager sessionManager;

    // template manager to customize the attributes used when creating objects

    private final TemplateManager templateManager;

    // flag indicating whether we need to explicitly cancel operations

    // we started on the token. If false, we assume operations are

    // automatically cancelled once we start another one

    final boolean explicitCancel;

    // translation cache for secret keys

    final KeyCache secretCache;

    // translation cache for asymmetric keys (public and private)

    final KeyCache privateCache;

    // cached instances of the various key factories, initialized on demand

    private volatile P11KeyFactory rsaFactory, dsaFactory, dhFactory, ecFactory;

    // table which maps mechanisms to the corresponding cached

    // MechanismInfo objects

    private final Map<Long, CK_MECHANISM_INFO> mechInfoMap;

    // single SecureRandomSpi instance we use per token

    // initialized on demand (if supported)

    private volatile P11SecureRandom secureRandom;

    // single KeyStoreSpi instance we use per provider

    // initialized on demand

    private volatile P11KeyStore keyStore;

    // whether this token is a removable token

    private final boolean removable;

    // for removable tokens: whether this token is valid or has been removed

    private volatile boolean valid;

    // for removable tokens: time last checked for token presence

    private long lastPresentCheck;

    // unique token id, used for serialization only

    private byte[] tokenId;

    // flag indicating whether the token is write protected

    private boolean writeProtected;

    // flag indicating whether we are logged in

    private volatile boolean loggedIn;

    // time we last checked login status

    private long lastLoginCheck;

    // mutex for token-present-check

    private final static Object CHECK_LOCK = new Object();

    // object for indicating unsupported mechanism in 'mechInfoMap'

    private final static CK_MECHANISM_INFO INVALID_MECH =

        new CK_MECHANISM_INFO(0, 0, 0);

    Token(SunPKCS11 provider) throws PKCS11Exception {

        this.provider = provider;

        this.removable = provider.removable;

        this.valid = true;

        p11 = provider.p11;

        config = provider.config;

        tokenInfo = p11.C_GetTokenInfo(provider.slotID);

        writeProtected = (tokenInfo.flags & CKF_WRITE_PROTECTED) != 0;

        // create session manager and open a test session

        SessionManager sessionManager;

        try {

            sessionManager = new SessionManager(this);

            Session s = sessionManager.getOpSession();

            sessionManager.releaseSession(s);

        } catch (PKCS11Exception e) {

            if (writeProtected) {

                throw e;

            }

            // token might not permit RW sessions even though

            // CKF_WRITE_PROTECTED is not set

            writeProtected = true;

            sessionManager = new SessionManager(this);

            Session s = sessionManager.getOpSession();

            sessionManager.releaseSession(s);

        }

        this.sessionManager = sessionManager;

        secretCache = new KeyCache();

        privateCache = new KeyCache();

        templateManager = config.getTemplateManager();

        explicitCancel = config.getExplicitCancel();

        mechInfoMap = Collections.synchronizedMap

            (new HashMap<Long, CK_MECHANISM_INFO>(10));

    }

    boolean isWriteProtected() {

        return writeProtected;

    }

    // return whether we are logged in

    // uses cached result if current. session is optional and may be null

    boolean isLoggedIn(Session session) throws PKCS11Exception {

        // volatile load first

        boolean loggedIn = this.loggedIn;

        long time = System.currentTimeMillis();

        if (time - lastLoginCheck > CHECK_INTERVAL) {

            loggedIn = isLoggedInNow(session);

            lastLoginCheck = time;

        }

        return loggedIn;

    }

    // return whether we are logged in now

    // does not use cache

    boolean isLoggedInNow(Session session) throws PKCS11Exception {

        boolean allocSession = (session == null);

        try {

            if (allocSession) {

                session = getOpSession();

            }

            CK_SESSION_INFO info = p11.C_GetSessionInfo(session.id());

            boolean loggedIn = (info.state == CKS_RO_USER_FUNCTIONS) ||

                                (info.state == CKS_RW_USER_FUNCTIONS);

            this.loggedIn = loggedIn;

            return loggedIn;

        } finally {

            if (allocSession) {

                releaseSession(session);

            }

        }

    }

    // ensure that we are logged in

    // call provider.login() if not

    void ensureLoggedIn(Session session) throws PKCS11Exception, LoginException {

        if (isLoggedIn(session) == false) {

            provider.login(null, null);

        }

    }

    // return whether this token object is valid (i.e. token not removed)

    // returns value from last check, does not perform new check

    boolean isValid() {

        if (removable == false) {

            return true;

        }

        return valid;

    }

    void ensureValid() {

        if (isValid() == false) {

            throw new ProviderException("Token has been removed");

        }

    }

    // return whether a token is present (i.e. token not removed)

    // returns cached value if current, otherwise performs new check

    boolean isPresent(Session session) {

        if (removable == false) {

            return true;

        }

        if (valid == false) {

            return false;

        }

        long time = System.currentTimeMillis();

        if ((time - lastPresentCheck) >= CHECK_INTERVAL) {

            synchronized (CHECK_LOCK) {

                if ((time - lastPresentCheck) >= CHECK_INTERVAL) {

                    boolean ok = false;

                    try {

                        // check if token still present

                        CK_SLOT_INFO slotInfo =

                                provider.p11.C_GetSlotInfo(provider.slotID);

                        if ((slotInfo.flags & CKF_TOKEN_PRESENT) != 0) {

                            // if the token has been removed and re-inserted,

                            // the token should return an error

                            CK_SESSION_INFO sessInfo =

                                    provider.p11.C_GetSessionInfo

                                    (session.idInternal());

                            ok = true;

                        }

                    } catch (PKCS11Exception e) {

                        // empty

                    }

                    valid = ok;

                    lastPresentCheck = System.currentTimeMillis();

                    if (ok == false) {

                        destroy();

                    }

                }

            }

        }

        return valid;

    }

    void destroy() {

        valid = false;

        provider.uninitToken(this);

    }

    Session getObjSession() throws PKCS11Exception {

        return sessionManager.getObjSession();

    }

    Session getOpSession() throws PKCS11Exception {

        return sessionManager.getOpSession();

    }

    Session releaseSession(Session session) {

        return sessionManager.releaseSession(session);

    }

    Session killSession(Session session) {

        return sessionManager.killSession(session);

    }

    CK_ATTRIBUTE[] getAttributes(String op, long type, long alg,

            CK_ATTRIBUTE[] attrs) throws PKCS11Exception {

        CK_ATTRIBUTE[] newAttrs =

                    templateManager.getAttributes(op, type, alg, attrs);

        for (CK_ATTRIBUTE attr : newAttrs) {

            if (attr.type == CKA_TOKEN) {

                if (attr.getBoolean()) {

                    try {

                        ensureLoggedIn(null);

                    } catch (LoginException e) {

                        throw new ProviderException("Login failed", e);

                    }

                }

                // break once we have found a CKA_TOKEN attribute

                break;

            }

        }

        return newAttrs;

    }

    P11KeyFactory getKeyFactory(String algorithm) {

        P11KeyFactory f;

        if (algorithm.equals("RSA")) {

            f = rsaFactory;

            if (f == null) {

                f = new P11RSAKeyFactory(this, algorithm);

                rsaFactory = f;

            }

        } else if (algorithm.equals("DSA")) {

            f = dsaFactory;

            if (f == null) {

                f = new P11DSAKeyFactory(this, algorithm);

                dsaFactory = f;

            }

        } else if (algorithm.equals("DH")) {

            f = dhFactory;

            if (f == null) {

                f = new P11DHKeyFactory(this, algorithm);

                dhFactory = f;

            }

        } else if (algorithm.equals("EC")) {

            f = ecFactory;

            if (f == null) {

                f = new P11ECKeyFactory(this, algorithm);

                ecFactory = f;

            }

        } else {

            throw new ProviderException("Unknown algorithm " + algorithm);

        }

        return f;

    }

    P11SecureRandom getRandom() {

        if (secureRandom == null) {

            secureRandom = new P11SecureRandom(this);

        }

        return secureRandom;

    }

    P11KeyStore getKeyStore() {

        if (keyStore == null) {

            keyStore = new P11KeyStore(this);

        }

        return keyStore;

    }

    CK_MECHANISM_INFO getMechanismInfo(long mechanism) throws PKCS11Exception {

        CK_MECHANISM_INFO result = mechInfoMap.get(mechanism);

        if (result == null) {

            try {

                result = p11.C_GetMechanismInfo(provider.slotID,

                                                mechanism);

                mechInfoMap.put(mechanism, result);

            } catch (PKCS11Exception e) {

                if (e.getErrorCode() != PKCS11Constants.CKR_MECHANISM_INVALID) {

                    throw e;

                } else {

                    mechInfoMap.put(mechanism, INVALID_MECH);

                }

            }

        } else if (result == INVALID_MECH) {

            result = null;

        }

        return result;

    }

    private synchronized byte[] getTokenId() {

        if (tokenId == null) {

            SecureRandom random = JCAUtil.getSecureRandom();

            tokenId = new byte[20];

            random.nextBytes(tokenId);

            serializedTokens.add(new WeakReference<Token>(this));

        }

        return tokenId;

    }

    // list of all tokens that have been serialized within this VM

    // NOTE that elements are never removed from this list

    // the assumption is that the number of tokens that are serialized

    // is relatively small

    private static final List<Reference<Token>> serializedTokens =

        new ArrayList<Reference<Token>>();

    private Object writeReplace() throws ObjectStreamException {

        if (isValid() == false) {

            throw new NotSerializableException("Token has been removed");

        }

        return new TokenRep(this);

    }

    // serialized representation of a token

    // tokens can only be de-serialized within the same VM invocation

    // and if the token has not been removed in the meantime

    private static class TokenRep implements Serializable {

        private static final long serialVersionUID = 3503721168218219807L;

        private final byte[] tokenId;

        TokenRep(Token token) {

            tokenId = token.getTokenId();

        }

        private Object readResolve() throws ObjectStreamException {

            for (Reference<Token> tokenRef : serializedTokens) {

                Token token = tokenRef.get();

                if ((token != null) && token.isValid()) {

                    if (Arrays.equals(token.getTokenId(), tokenId)) {

                        return token;

                    }

                }

            }

            throw new NotSerializableException("Could not find token");

        }

    }

}