/*

 * Copyright (c) 2016, 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.

 *

 * 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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 * questions.

 */

/*

 * @test

 * @bug 8141039

 * @library /lib/testlibrary

 * @summary Check SecureRandom generate expected seed counts what the caller

 *          asked for.

 * @run main/othervm EnoughSeedTest

 */

import java.security.SecureRandom;

import java.security.Security;

import static java.lang.Math.*;

public class EnoughSeedTest {

    private static final String DRBG_CONFIG = "securerandom.drbg.config";

    private static final String DRBG_CONFIG_VALUE

            = Security.getProperty(DRBG_CONFIG);

    public static void main(String[] args) {

        System.setProperty("java.security.egd", "file:/dev/urandom");

        boolean success = true;

        for (String mech : new String[]{

            "SHA1PRNG", "Hash_DRBG", "HMAC_DRBG", "CTR_DRBG"}) {

            System.out.printf("%nTest for SecureRandom algorithm: '%s'", mech);

            try {

                SecureRandom sr = null;

                if (!mech.contains("_DRBG")) {

                    sr = SecureRandom.getInstance(mech);

                } else {

                    Security.setProperty(DRBG_CONFIG, mech);

                    sr = SecureRandom.getInstance("DRBG");

                }

                success &= forEachSeedBytes(sr);

                System.out.printf("%nCompleted test for SecureRandom "

                        + "mechanism: '%s'", mech);

            } catch (Exception e) {

                success &= false;

                e.printStackTrace(System.out);

            } finally {

                Security.setProperty(DRBG_CONFIG, DRBG_CONFIG_VALUE);

            }

        }

        if (!success) {

            throw new RuntimeException("At least one test failed.");

        }

    }

    /**

     * Generates fixed number of seed bytes through a SecureRandom instance

     * to verify it's seed generation status.

     * @param sr SecureRandom instance

     * @return The test success indicator

     */

    private static boolean forEachSeedBytes(SecureRandom sr) {

        boolean success = true;

        sr.setSeed(1l);

        for (int seedByte : new int[]{Integer.MIN_VALUE, -1, 0, 1, 256, 1024,

            Short.MAX_VALUE, (int) pow(2, 20)}) {

            try {

                byte[] seed = sr.generateSeed(seedByte);

                if (seed.length != seedByte) {

                    throw new RuntimeException("Not able to produce expected "

                            + "seed size.");

                }

            } catch (IllegalArgumentException e) {

                if (seedByte >= 0) {

                    throw new RuntimeException("Unknown Exception occured.", e);

                }

                System.out.printf("%nPASS - Exception expected when required "

                        + "seed size requested is negative: %s", seedByte);

            }

        }

        return success;

    }

}