1 /*
   2  * Copyright (c) 2017, 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 /*
  25  * @test
  26  * @bug 8164512 8191360
  27  * @requires vm.compMode != "Xcomp"
  28  * @requires !vm.musl
  29  * @summary verify if the native library is unloaded when the class loader is GC'ed
  30  * @build p.Test
  31  * @run main/othervm/native -Xcheck:jni NativeLibraryTest
  32  */
  33 
  34  // Clarification on @requires declarations:
  35  // Under musl, dlclose is a no-op. The static variable 'count' in libnative.c keeps
  36  // its value across a GC and the check in Test.java fails.
  37 
  38 import java.io.IOException;
  39 import java.net.MalformedURLException;
  40 import java.net.URL;
  41 import java.net.URLClassLoader;
  42 import java.nio.file.Files;
  43 import java.nio.file.Path;
  44 import java.nio.file.Paths;
  45 
  46 public class NativeLibraryTest {
  47     static final Path CLASSES = Paths.get("classes");
  48     static int unloadedCount = 0;
  49 
  50     /*
  51      * Called by JNI_OnUnload when the native library is unloaded
  52      */
  53     static void nativeLibraryUnloaded() {
  54         unloadedCount++;
  55     }
  56 
  57     public static void main(String... args) throws Exception {
  58         setup();
  59 
  60         for (int count=1; count <= 5; count++) {
  61             // create a class loader and load a native library
  62             runTest();
  63             // unloading the class loader and native library
  64             System.gc();
  65             // give Cleaner thread a chance to unload the native library
  66             Thread.sleep(100);
  67 
  68             // unloadedCount is incremented when the native library is unloaded
  69             if (count != unloadedCount) {
  70                 throw new RuntimeException("Expected unloaded=" + count +
  71                     " but got=" + unloadedCount);
  72             }
  73         }
  74     }
  75 
  76     /*
  77      * Loads p.Test class with a new class loader and its static initializer
  78      * will load a native library.
  79      *
  80      * The class loader becomes unreachable when this method returns and
  81      * the native library should be unloaded at some point after the class
  82      * loader is garbage collected.
  83      */
  84     static void runTest() throws Exception {
  85         // invoke p.Test.run() that loads the native library
  86         Runnable r = newTestRunnable();
  87         r.run();
  88 
  89         // reload the native library by the same class loader
  90         r.run();
  91 
  92         // load the native library by another class loader
  93         Runnable r1 = newTestRunnable();
  94         try {
  95             r1.run();
  96             throw new RuntimeException("should fail to load the native library" +
  97                     " by another class loader");
  98         } catch (UnsatisfiedLinkError e) {}
  99     }
 100 
 101     /*
 102      * Loads p.Test class with a new class loader and returns
 103      * a Runnable instance.
 104      */
 105     static Runnable newTestRunnable() throws Exception {
 106         TestLoader loader = new TestLoader();
 107         Class<?> c = Class.forName("p.Test", true, loader);
 108         return (Runnable) c.newInstance();
 109     }
 110 
 111     static class TestLoader extends URLClassLoader {
 112         static URL[] toURLs() {
 113             try {
 114                 return new URL[] { CLASSES.toUri().toURL() };
 115             } catch (MalformedURLException e) {
 116                 throw new Error(e);
 117             }
 118         }
 119 
 120         TestLoader() {
 121             super("testloader", toURLs(), ClassLoader.getSystemClassLoader());
 122         }
 123     }
 124 
 125     /*
 126      * move p/Test.class out from classpath to the scratch directory
 127      */
 128     static void setup() throws IOException {
 129         String dir = System.getProperty("test.classes", ".");
 130         Path file = Paths.get("p", "Test.class");
 131         Files.createDirectories(CLASSES.resolve("p"));
 132         Files.move(Paths.get(dir).resolve(file),
 133                    CLASSES.resolve("p").resolve("Test.class"));
 134     }
 135 }