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 * Copyright (c) 2003, 2013, 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

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package sun.security.jca;

import java.io.File;

import java.lang.reflect.*;

import java.security.*;

import sun.security.util.PropertyExpander;

/**

 * Class representing a configured provider. Encapsulates configuration

 * (className plus optional argument), the provider loading logic, and

 * the loaded Provider object itself.

 *

 * @author  Andreas Sterbenz

 * @since   1.5

 */

final class ProviderConfig {

    private final static sun.security.util.Debug debug =

        sun.security.util.Debug.getInstance("jca", "ProviderConfig");

    // classname of the SunPKCS11-Solaris provider

    private static final String P11_SOL_NAME =

        "sun.security.pkcs11.SunPKCS11";

    // config file argument of the SunPKCS11-Solaris provider

    private static final String P11_SOL_ARG  =

    // maximum number of times to try loading a provider before giving up

    private final static int MAX_LOAD_TRIES = 30;

    // parameters for the Provider(String) constructor,

    // use by doLoadProvider()

    private final static Class<?>[] CL_STRING = { String.class };

    // name of the provider class

    private final String className;

    // argument to the provider constructor,

    // empty string indicates no-arg constructor

    private final String argument;

    // number of times we have already tried to load this provider

    private int tries;

    // Provider object, if loaded

    private volatile Provider provider;

    // flag indicating if we are currently trying to load the provider

    // used to detect recursion

    private boolean isLoading;

    ProviderConfig(String className, String argument) {

        if (className.equals(P11_SOL_NAME) && argument.equals(P11_SOL_ARG)) {

            checkSunPKCS11Solaris();

        }

        this.className = className;

        this.argument = expand(argument);

    }

    ProviderConfig(String className) {

        this(className, "");

    }

    ProviderConfig(Provider provider) {

        this.className = provider.getClass().getName();

        this.argument = "";

        this.provider = provider;

    }

    // check if we should try to load the SunPKCS11-Solaris provider

    // avoid if not available (pre Solaris 10) to reduce startup time

    // or if disabled via system property

    private void checkSunPKCS11Solaris() {

        Boolean o = AccessController.doPrivileged(

                                new PrivilegedAction<Boolean>() {

            public Boolean run() {

                File file = new File("/usr/lib/libpkcs11.so");

                if (file.exists() == false) {

                    return Boolean.FALSE;

                }

                if ("false".equalsIgnoreCase(System.getProperty

                        ("sun.security.pkcs11.enable-solaris"))) {

                    return Boolean.FALSE;

                }

                return Boolean.TRUE;

            }

        });

        if (o == Boolean.FALSE) {

            tries = MAX_LOAD_TRIES;

        }

    }

    private boolean hasArgument() {

        return argument.length() != 0;

    }

    // should we try to load this provider?

    private boolean shouldLoad() {

        return (tries < MAX_LOAD_TRIES);

    }

    // do not try to load this provider again

    private void disableLoad() {

        tries = MAX_LOAD_TRIES;

    }

    boolean isLoaded() {

        return (provider != null);

    }

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof ProviderConfig == false) {

            return false;

        }

        ProviderConfig other = (ProviderConfig)obj;

        return this.className.equals(other.className)

            && this.argument.equals(other.argument);

    }

    public int hashCode() {

        return className.hashCode() + argument.hashCode();

    }

    public String toString() {

        if (hasArgument()) {

            return className + "('" + argument + "')";

        } else {

            return className;

        }

    }

    /**

     * Get the provider object. Loads the provider if it is not already loaded.

     */

    synchronized Provider getProvider() {

        // volatile variable load

        Provider p = provider;

        if (p != null) {

            return p;

        }

        if (shouldLoad() == false) {

            return null;

        }

        if (isLoading) {

            // because this method is synchronized, this can only

            // happen if there is recursion.

            if (debug != null) {

                debug.println("Recursion loading provider: " + this);

                new Exception("Call trace").printStackTrace();

            }

            return null;

        }

        try {

            isLoading = true;

            tries++;

            p = doLoadProvider();

        } finally {

            isLoading = false;

        }

        provider = p;

        return p;

    }

    /**

     * Load and instantiate the Provider described by this class.

     *

     * NOTE use of doPrivileged().

     *

     * @return null if the Provider could not be loaded

     *

     * @throws ProviderException if executing the Provider's constructor

     * throws a ProviderException. All other Exceptions are ignored.

     */

    private Provider doLoadProvider() {

        return AccessController.doPrivileged(new PrivilegedAction<Provider>() {

            public Provider run() {

                if (debug != null) {

                    debug.println("Loading provider: " + ProviderConfig.this);

                }

                try {

                    ClassLoader cl = ClassLoader.getSystemClassLoader();

                    Class<?> provClass;

                    if (cl != null) {

                        provClass = cl.loadClass(className);

                    } else {

                        provClass = Class.forName(className);

                    }

                    Object obj;

                    if (hasArgument() == false) {

                        obj = provClass.newInstance();

                    } else {

                        Constructor<?> cons = provClass.getConstructor(CL_STRING);

                        obj = cons.newInstance(argument);

                    }

                    if (obj instanceof Provider) {

                        if (debug != null) {

                            debug.println("Loaded provider " + obj);

                        }

                        return (Provider)obj;

                    } else {

                        if (debug != null) {

                            debug.println(className + " is not a provider");

                        }

                        disableLoad();

                        return null;

                    }

                } catch (Exception e) {

                    Throwable t;

                    if (e instanceof InvocationTargetException) {

                        t = ((InvocationTargetException)e).getCause();

                    } else {

                        t = e;

                    }

                    if (debug != null) {

                        debug.println("Error loading provider " + ProviderConfig.this);

                        t.printStackTrace();

                    }

                    // provider indicates fatal error, pass through exception

                    if (t instanceof ProviderException) {

                        throw (ProviderException)t;

                    }

                    // provider indicates that loading should not be retried

                    if (t instanceof UnsupportedOperationException) {

                        disableLoad();

                    }

                    return null;

                } catch (ExceptionInInitializerError err) {

                    // no sufficient permission to initialize provider class

                    if (debug != null) {

                        debug.println("Error loading provider " + ProviderConfig.this);

                        err.printStackTrace();

                    }

                    disableLoad();

                    return null;

                }

            }

        });

    }

    /**

     * Perform property expansion of the provider value.

     *

     * NOTE use of doPrivileged().

     */

    private static String expand(final String value) {

        // shortcut if value does not contain any properties

        if (value.contains("${") == false) {

            return value;

        }

        return AccessController.doPrivileged(new PrivilegedAction<String>() {

            public String run() {

                try {

                    return PropertyExpander.expand(value);

                } catch (GeneralSecurityException e) {

                    throw new ProviderException(e);

                }

            }

        });

    }

}