Quelle SecurityRace.java Sprache: JAVA

/*
* Copyright (c) 2005, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/

/*
* @test
* @bug 6302839
* @summary SecurityRace System field accesses in two threads
* @author Pete Soper
* @build SecurityRace
* @run main/othervm/policy=System.policy SecurityRace
*/

/*
* By default the test runs for a very short time.  Use main arg "stress"
* to have a real chance of exposing races. Use main arg "time" to report
* the average nanoseconds per invocation of System.setSecurityManager and
* System.getSecurityManager. No testing for access races is performed with
* argument "time."
*
* Requires security permissions "setSecurityManager" and
* "createSecurityManager."
*/

public class SecurityRace implements Runnable {

    // Number of iterations to "warm up" and get methods compiled/inlined.
    // (this is conservative)
    static final int WARMUP_LOOPS = 100000;

    // Number of timing trials
    static final int TIMING_TRIALS = 10;

    // Seconds to run this in "stress" mode. This is double the average
    // time to expose the races of bug 6302839 on a Blade 1000. Invoke
    // the program with the "stress" option multiple times for more
    // confidence.
    static final int STRESS_MILLISECONDS = 300000;
    static final int SET_TIMING_LOOPS    = 10000;

    // Max seconds to run before terminating the test ("declaring victory").
    static int MAX_MILLISECONDS = 100;

    // Number of iterations to time
    static final int GET_TIMING_LOOPS = 10000000;

    // Set true by main thread when NPE caught or time to terminate.
    // Set true by other thread when NPE caught. It makes
    // no difference where the NPE is thrown.
    static volatile boolean stopthreads = false;

    // Number of getProperty invocations between main loop checks
    static final int       GETPROPERTY_LOOPS = 30000;

    // Used by race and timing tests. Must get set non-null at lease once.
    static SecurityManager sm = new SecurityManager();

    public static void main(String[] argv) throws Exception {
        String s;

        if (argv.length > 0) {
            if (argv[0].equals("time")) {

                // Run the timing method
                // First warm up the method to make sure it gets compiled
                for (int i = 0; i < WARMUP_LOOPS; i++) {
                    timeit(1, 1, 1);
                }

                System.out.println("boo");

                // Now do the actual timing
                timeit(TIMING_TRIALS, GET_TIMING_LOOPS, SET_TIMING_LOOPS);
            } else if (argv[0].equals("stress")) {

                // For stress test the test duration is boosted
                MAX_MILLISECONDS = STRESS_MILLISECONDS;
            } else {
                throw new RuntimeException(
                    "SecurityRace: " + argv[0]
                    + " argument to main not recognized");
            }    // if argv
        }        // if length

        long start = System.currentTimeMillis(),
             end   = start + MAX_MILLISECONDS;

        // Create and start racing thread
        (new Thread(new SecurityRace())).start();

        // main thread alternates batches of getProperty() with time checks
        try {
            do {
                if (stopthreads) {

                    // other thread suffered an NPE
                    throw new RuntimeException("SecurityRace failed with NPE");
                }

                for (int i = 0; i < GETPROPERTY_LOOPS; i++) {
                    s = System.getProperty("java.version");
                }
            } while (System.currentTimeMillis() < end);
        } catch (NullPointerException e) {
            throw new RuntimeException("SecurityRace failed with NPE");
        } finally {

            // make sure other thread terminates
            stopthreads = true;
        }
    }    // main

    // System.security mutator.
    public void run() {
        try {
            while (true) {
                if (stopthreads) {
                    return;
                }

                System.setSecurityManager(sm);

                // The goal is to catch another thread testing the
                // value set above and trying to use it after it's
                // nulled below.
                System.setSecurityManager(null);
            }
        } catch (NullPointerException e) {
            stopthreads = true;

            return;
        }
    }

    // Time method execution. Collects trials number of timings
    // for the number of accessor and mutator invocation loops
    // specified.
    public static void timeit(int timing_trials, int get_timing_loops,
                              int set_timing_loops) {
        try {
            long start;

            // Time the methods and report average.
            // Time multiple trials so noise is apparent and a
            // T test can be used to establish significance.
            for (int j = 0; j < timing_trials; j++) {
                start = System.nanoTime();

                for (int i = 0; i < get_timing_loops; i++) {
                    sm = System.getSecurityManager();
                }

                // Don't print for "warmup" case. This might mean that
                // the compiler fails to compile the println (setting it
                // up to execute via interpretation using an "uncommon trap")
                // but we don't care if this println runs slowly!
                if (timing_trials > 1) {
                    System.out.println((float) (System.nanoTime() - start)
                                       / (float) get_timing_loops);
                }
            }

            for (int j = 0; j < timing_trials; j++) {
                start = System.nanoTime();

                for (int i = 0; i < set_timing_loops; i++) {
                    System.setSecurityManager(sm);
                }

                if (timing_trials > 1) {
                    System.out.println((float) (System.nanoTime() - start)
                                       / (float) set_timing_loops);
                }
            }

            return;
        } catch (Exception e) {
            throw new RuntimeException("SecurityRace got unexpected: " + e);
        }
    }    // timeit
}    // SecurityRace

quality92%

¤ Dauer der Verarbeitung: 0.14 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.