138 lines
4.7 KiB
Java
138 lines
4.7 KiB
Java
/*
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* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/* @test
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* @bug 8012019
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* @summary Tests interruption of threads doing position-based read methods in
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* an attempt to provoke a deadlock between position sensitive and position
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* insensitive methods
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*/
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import java.nio.ByteBuffer;
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import java.nio.channels.*;
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import java.nio.file.*;
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import static java.nio.file.StandardOpenOption.*;
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public class InterruptDeadlock {
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/**
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* A thread that continuously reads from a FileChannel with
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* read(ByteBuffer,long). The thread terminates when interrupted and/or
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* the FileChannel is closed.
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*/
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static class Reader extends Thread {
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final FileChannel fc;
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volatile Exception exception;
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Reader(FileChannel fc) {
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this.fc = fc;
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}
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@Override
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public void run() {
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ByteBuffer bb = ByteBuffer.allocate(1024);
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try {
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long pos = 0L;
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for (;;) {
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bb.clear();
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int n = fc.read(bb, pos);
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if (n > 0)
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pos += n;
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// fc.size is important here as it is position sensitive
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if (pos >= fc.size())
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pos = 0L;
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}
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} catch (ClosedChannelException x) {
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System.out.println(x.getClass() + " (expected)");
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} catch (Exception unexpected) {
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this.exception = unexpected;
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}
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}
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Exception exception() {
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return exception;
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}
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static Reader startReader(FileChannel fc) {
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Reader r = new Reader(fc);
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r.start();
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return r;
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}
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}
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// the number of reader threads to start
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private static final int READER_COUNT = 4;
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public static void main(String[] args) throws Exception {
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Path file = Paths.get("data.txt");
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try (FileChannel fc = FileChannel.open(file, CREATE, TRUNCATE_EXISTING, WRITE)) {
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fc.position(1024L * 1024L);
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fc.write(ByteBuffer.wrap(new byte[1]));
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}
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Reader[] readers = new Reader[READER_COUNT];
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for (int i=1; i<=20; i++) {
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System.out.format("Iteration: %s%n", i);
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try (FileChannel fc = FileChannel.open(file)) {
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boolean failed = false;
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// start reader threads
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for (int j=0; j<READER_COUNT; j++) {
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readers[j] = Reader.startReader(fc);
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}
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// give readers a bit of time to get started (not strictly required)
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Thread.sleep(100);
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// interrupt and wait for the readers to terminate
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for (Reader r: readers) {
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r.interrupt();
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}
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for (Reader r: readers) {
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try {
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r.join(10000);
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Exception e = r.exception();
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if (e != null) {
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System.err.println("Reader thread failed with: " + e);
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failed = true;
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}
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} catch (InterruptedException x) {
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System.err.println("Reader thread did not terminte");
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failed = true;
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}
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}
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// the channel should not be open at this point
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if (fc.isOpen()) {
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System.err.println("FileChannel was not closed");
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failed = true;
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}
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if (failed)
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throw new RuntimeException("Test failed - see log for details");
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}
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}
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}
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}
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