com.dalabs.droop.util.password.CredentialProviderHelper.java Source code

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Here is the source code for com.dalabs.droop.util.password.CredentialProviderHelper.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.dalabs.droop.util.password;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;

/**
 * Helper class for the Hadoop credential provider functionality.
 * Reflrection to used to avoid directly referencing the classes and methods
 * so that version dependency is not introduced as the Hadoop credential
 * provider is only introduced in 2.6.0 and later
 */
public class CredentialProviderHelper {
    public static final Log LOG = LogFactory.getLog(CredentialProviderHelper.class.getName());

    private static Class<?> clsCredProvider;
    private static Class<?> clsCredProviderFactory;
    private static Method methGetPassword;
    private static Method methGetProviders;
    private static Method methCreateCredEntry;
    private static Method methFlush;

    static {
        try {
            LOG.debug("Reflecting credential provider classes and methods");
            clsCredProvider = Class.forName("org.apache.hadoop.security.alias.CredentialProvider");
            LOG.debug("Found org.apache.hadoop.security.alias.CredentialProvider");
            clsCredProviderFactory = Class.forName("org.apache.hadoop.security.alias.CredentialProviderFactory");
            LOG.debug("Found org.apache.hadoop.security.alias.CredentialProviderFactory");

            methCreateCredEntry = clsCredProvider.getMethod("createCredentialEntry",
                    new Class[] { String.class, char[].class });
            LOG.debug("Found CredentialProvider#createCredentialEntry");

            methFlush = clsCredProvider.getMethod("flush", new Class[] {});
            LOG.debug("Found CredentialProvider#flush");

            methGetPassword = Configuration.class.getMethod("getPassword", new Class[] { String.class });
            LOG.debug("Found Configuration#getPassword");

            methGetProviders = clsCredProviderFactory.getMethod("getProviders",
                    new Class[] { Configuration.class });
            LOG.debug("Found CredentialProviderFactory#getProviders");
        } catch (ClassNotFoundException cnfe) {
            LOG.debug("Ignoring exception", cnfe);
        } catch (NoSuchMethodException nsme) {
            LOG.debug("Ignoring exception", nsme);
        }
    }
    // Should track what is specified in JavaKeyStoreProvider class.
    public static final String SCHEME_NAME = "jceks";
    // Should track what is in CredentialProvider class.
    public static final String CREDENTIAL_PROVIDER_PATH = "hadoop.security.credential.provider.path";

    public static boolean isProviderAvailable() {

        if (clsCredProvider == null || clsCredProviderFactory == null || methCreateCredEntry == null
                || methGetPassword == null || methFlush == null) {
            return false;
        }
        return true;
    }

    public static String resolveAlias(Configuration conf, String alias) throws IOException {
        LOG.debug("Resolving alias with credential provider path set to " + conf.get(CREDENTIAL_PROVIDER_PATH));
        try {
            char[] cred = (char[]) methGetPassword.invoke(conf, new Object[] { alias });
            if (cred == null) {
                throw new IOException("The provided alias cannot be resolved");
            }
            String pass = new String(cred);
            return pass;
        } catch (InvocationTargetException ite) {
            throw new RuntimeException("Error resolving password " + " from the credential providers ",
                    ite.getTargetException());
        } catch (IllegalAccessException iae) {
            throw new RuntimeException("Error invoking the credential provider method", iae);
        }
    }

    /**
     * Test utility to create an entry
     */
    public static void createCredentialEntry(Configuration conf,

            String alias, String credential) throws IOException {

        if (!isProviderAvailable()) {
            throw new RuntimeException("CredentialProvider facility not available " + "in the hadoop environment");
        }

        try {
            List<?> result = (List<?>) methGetProviders.invoke(null, new Object[] { conf });
            Object provider = result.get(0);
            LOG.debug("Using credential provider " + provider);

            methCreateCredEntry.invoke(provider, new Object[] { alias, credential.toCharArray() });
            methFlush.invoke(provider, new Object[] {});
        } catch (InvocationTargetException ite) {
            throw new RuntimeException("Error creating credential entry " + " using the credentail provider",
                    ite.getTargetException());
        } catch (IllegalAccessException iae) {
            throw new RuntimeException("Error accessing the credential create method", iae);
        }
    }
}