| /* |
| * Copyright (c) 2017, 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 8012019 |
| * @summary Tests interruption of threads doing position-based read methods in |
| * an attempt to provoke a deadlock between position sensitive and position |
| * insensitive methods |
| */ |
| import java.nio.ByteBuffer; |
| import java.nio.channels.*; |
| import java.nio.file.*; |
| import static java.nio.file.StandardOpenOption.*; |
| |
| public class InterruptDeadlock { |
| |
| /** |
| * A thread that continuously reads from a FileChannel with |
| * read(ByteBuffer,long). The thread terminates when interrupted and/or |
| * the FileChannel is closed. |
| */ |
| static class Reader extends Thread { |
| final FileChannel fc; |
| volatile Exception exception; |
| |
| Reader(FileChannel fc) { |
| this.fc = fc; |
| } |
| |
| @Override |
| public void run() { |
| ByteBuffer bb = ByteBuffer.allocate(1024); |
| try { |
| long pos = 0L; |
| for (;;) { |
| bb.clear(); |
| int n = fc.read(bb, pos); |
| if (n > 0) |
| pos += n; |
| // fc.size is important here as it is position sensitive |
| if (pos >= fc.size()) |
| pos = 0L; |
| } |
| } catch (ClosedChannelException x) { |
| System.out.println(x.getClass() + " (expected)"); |
| } catch (Exception unexpected) { |
| this.exception = unexpected; |
| } |
| } |
| |
| Exception exception() { |
| return exception; |
| } |
| |
| static Reader startReader(FileChannel fc) { |
| Reader r = new Reader(fc); |
| r.start(); |
| return r; |
| } |
| } |
| |
| // the number of reader threads to start |
| private static final int READER_COUNT = 4; |
| |
| public static void main(String[] args) throws Exception { |
| Path file = Paths.get("data.txt"); |
| try (FileChannel fc = FileChannel.open(file, CREATE, TRUNCATE_EXISTING, WRITE)) { |
| fc.position(1024L * 1024L); |
| fc.write(ByteBuffer.wrap(new byte[1])); |
| } |
| |
| Reader[] readers = new Reader[READER_COUNT]; |
| |
| for (int i=1; i<=20; i++) { |
| System.out.format("Iteration: %s%n", i); |
| |
| try (FileChannel fc = FileChannel.open(file)) { |
| boolean failed = false; |
| |
| // start reader threads |
| for (int j=0; j<READER_COUNT; j++) { |
| readers[j] = Reader.startReader(fc); |
| } |
| |
| // give readers a bit of time to get started (not strictly required) |
| Thread.sleep(100); |
| |
| // interrupt and wait for the readers to terminate |
| for (Reader r: readers) { |
| r.interrupt(); |
| } |
| for (Reader r: readers) { |
| try { |
| r.join(10000); |
| Exception e = r.exception(); |
| if (e != null) { |
| System.err.println("Reader thread failed with: " + e); |
| failed = true; |
| } |
| } catch (InterruptedException x) { |
| System.err.println("Reader thread did not terminte"); |
| failed = true; |
| } |
| } |
| |
| // the channel should not be open at this point |
| if (fc.isOpen()) { |
| System.err.println("FileChannel was not closed"); |
| failed = true; |
| } |
| |
| if (failed) |
| throw new RuntimeException("Test failed - see log for details"); |
| } |
| } |
| } |
| } |