1 /*
2 * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /* @test
25 * @bug 8147615
26 * @summary Test whether an unreferenced FileChannel is actually cleaned
27 * @requires (os.family == "linux") | (os.family == "mac") | (os.family == "solaris") | (os.family == "aix")
28 * @library /test/lib
29 * @build jdk.test.lib.util.FileUtils CleanerTest
30 * @modules java.management java.base/sun.nio.ch:+open
31 * @run main/othervm CleanerTest
32 */
33
34 import com.sun.management.UnixOperatingSystemMXBean;
35 import java.lang.management.ManagementFactory;
36 import java.lang.management.OperatingSystemMXBean;
37 import java.lang.ref.PhantomReference;
38 import java.lang.ref.Reference;
39 import java.lang.ref.ReferenceQueue;
40 import java.lang.ref.PhantomReference;
41 import java.lang.ref.WeakReference;
42 import java.lang.reflect.Field;
43 import java.nio.channels.FileChannel;
44 import java.nio.file.Files;
45 import java.nio.file.Path;
46 import java.nio.file.Paths;
47 import java.nio.file.StandardOpenOption;
48 import java.util.HashSet;
49
50 import jdk.test.lib.util.FileUtils;
51
52 import sun.nio.ch.FileChannelImpl;
53
54 public class CleanerTest {
55 public static void main(String[] args) throws Throwable {
56 OperatingSystemMXBean mxBean =
57 ManagementFactory.getOperatingSystemMXBean();
58 UnixOperatingSystemMXBean unixMxBean = null;
59 if (mxBean instanceof UnixOperatingSystemMXBean) {
60 unixMxBean = (UnixOperatingSystemMXBean)mxBean;
61 } else {
62 System.out.println("Non-Unix system: skipping test.");
63 return;
64 }
65
66 FileUtils.listFileDescriptors(System.out);
67 long fdCount0 = unixMxBean.getOpenFileDescriptorCount();
68
69 Path path = Paths.get(System.getProperty("test.dir", "."), "junk");
70 try {
71 FileChannel fc = FileChannel.open(path, StandardOpenOption.CREATE,
72 StandardOpenOption.READ, StandardOpenOption.WRITE);
73
74 // Prepare to wait for Channel, FD and Cleaner to be reclaimed
75 ReferenceQueue<Object> refQueue = new ReferenceQueue<>();
76 HashSet<Reference<?>> pending = new HashSet<>();
77
78 Reference<Object> fcRef = new PhantomReference<>(fc, refQueue);
79 pending.add(fcRef);
80
81 Field fdField = FileChannelImpl.class.getDeclaredField("fd");
82 fdField.setAccessible(true);
83 Object fd = fdField.get(fc); // get the fd from the channel
84 WeakReference<Object> fdWeak = new WeakReference<>(fd, refQueue);
85 pending.add(fdWeak);
86
87 Field closerField = FileChannelImpl.class.getDeclaredField("closer");
88 closerField.setAccessible(true);
89 Object closer = closerField.get(fc);
90 System.out.printf(" cleanup: %s, fd: %s, cf: %s%n", fc, fd, closer);
91
92 if (closer != null) {
93 WeakReference<Object> closerWeak = new WeakReference<>(closer, refQueue);
94 pending.add(closerWeak);
95 System.out.printf(" closerWeak: %s%n", closerWeak);
96 }
97
98 // Wait for all of the objects being tracked to be reclaimed;
99 // The test will timeout if they are not reclaimed within the jtreg timeout
100 Reference<?> r;
101 while (((r = refQueue.remove(1000L)) != null)
102 || !pending.isEmpty()) {
103 System.out.printf(" r: %s, pending: %d%n", r, pending.size());
104 if (r != null) {
105 pending.remove(r);
106 } else {
107 fc = null;
108 fd = null;
109 closer = null;
110 System.gc(); // attempt to reclaim them
111 }
112 }
113
114 Reference.reachabilityFence(fc);
115 Reference.reachabilityFence(fd);
116 Reference.reachabilityFence(closer);
117
118 long fdCount = unixMxBean.getOpenFileDescriptorCount();
119 if (fdCount != fdCount0) {
120 // Add debugging info about file descriptor changes
121 System.out.printf("initial count of open file descriptors: %d%n", fdCount0);
122 System.out.printf("final count of open file descriptors: %d%n", fdCount);
123 FileUtils.listFileDescriptors(System.out);
124 }
125 } finally {
126 Files.delete(path);
127 }
128 }
129 }