8187305: Add logging for shared library loads/unloads

Add logging to JVM_LoadLibrary(), JVM_UnloadLibrary(), and JVM_FindLibraryEntry().

Reviewed-by: dholmes, coleenp

src/hotspot/share/logging/logTag.hpp

@@ -89,6 +89,7 @@
   LOG_TAG(jit) \
   LOG_TAG(jni) \
   LOG_TAG(jvmti) \
+  LOG_TAG(library) \
   LOG_TAG(liveness) \
   LOG_TAG(load) /* Trace all classes loaded */ \
   LOG_TAG(loader) \

src/hotspot/share/prims/jvm.cpp

@@ -3371,19 +3371,25 @@ JVM_ENTRY_NO_ENV(void*, JVM_LoadLibrary(const char* name))
 
     THROW_HANDLE_0(h_exception);
   }
+  log_info(library)("Loaded library %s, handle " INTPTR_FORMAT, name, p2i(load_result));
   return load_result;
 JVM_END
 
 
 JVM_LEAF(void, JVM_UnloadLibrary(void* handle))
   JVMWrapper("JVM_UnloadLibrary");
   os::dll_unload(handle);
+  log_info(library)("Unloaded library with handle " INTPTR_FORMAT, p2i(handle));
 JVM_END
 
 
 JVM_LEAF(void*, JVM_FindLibraryEntry(void* handle, const char* name))
   JVMWrapper("JVM_FindLibraryEntry");
-  return os::dll_lookup(handle, name);
+  void* find_result = os::dll_lookup(handle, name);
+  log_info(library)("%s %s in library with handle " INTPTR_FORMAT,
+                    find_result != NULL ? "Found" : "Failed to find",
+                    name, p2i(handle));
+  return find_result;
 JVM_END
 
 

test/hotspot/jtreg/runtime/logging/loadLibraryTest/LoadLibrary.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2020, 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.
+ */
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+
+public class LoadLibrary {
+
+    public static String testClasses;
+
+    public static void runTest() throws Exception {
+        // create a classloader and load a class that loads a library.
+        MyClassLoader myLoader = new MyClassLoader();
+        Class<?> c = Class.forName("LoadLibraryClass", true, myLoader);
+    }
+
+    public static void main(String[] args) throws Exception {
+        testClasses = args[0];
+        runTest();
+        ClassUnloadCommon.triggerUnloading();
+    }
+
+    public static class MyClassLoader extends ClassLoader {
+
+        public static final String CLASS_NAME = "LoadLibraryClass";
+
+        static ByteBuffer readClassFile(String name) {
+            File f = new File(testClasses, name);
+            try (FileInputStream fin = new FileInputStream(f);
+                 FileChannel fc = fin.getChannel())
+            {
+                return fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
+            } catch (IOException e) {
+                throw new RuntimeException("Can't open file: " + name +
+                                           ", exception: " + e.toString());
+            }
+        }
+
+        protected Class<?> loadClass(String name, boolean resolve)
+            throws ClassNotFoundException {
+            Class<?> c;
+            if (!"LoadLibraryClass".equals(name)) {
+                c = super.loadClass(name, resolve);
+            } else {
+                // should not delegate to the system class loader
+                c = findClass(name);
+                if (resolve) {
+                    resolveClass(c);
+                }
+            }
+            return c;
+        }
+
+        protected Class<?> findClass(String name) throws ClassNotFoundException {
+            if (!"LoadLibraryClass".equals(name)) {
+                throw new ClassNotFoundException("Unexpected class: " + name);
+            }
+            return defineClass(name, readClassFile(name + ".class"), null);
+        }
+    } // MyClassLoader
+
+}
+
+
+class LoadLibraryClass {
+    static {
+        System.loadLibrary("LoadLibraryClass");
+        nTest();
+    }
+    native static void nTest();
+}

test/hotspot/jtreg/runtime/logging/loadLibraryTest/LoadLibraryTest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2020, 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 8187305
+ * @summary Tests logging of shared library loads and unloads.
+ * @library /runtime/testlibrary /test/lib
+ * @compile LoadLibrary.java
+ * @run main LoadLibraryTest
+ */
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+public class LoadLibraryTest {
+
+    public static void main(String... args) throws Exception {
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+            "-Xlog:library=info", "-Djava.library.path=" + System.getProperty("java.library.path"),
+            "LoadLibrary", System.getProperty("test.classes"));
+
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        output.shouldContain("Loaded library");
+        output.shouldContain("Found Java_LoadLibraryClass_nTest in library");
+        output.shouldContain("Unloaded library with handle");
+        output.shouldHaveExitValue(0);
+    }
+}

test/hotspot/jtreg/runtime/logging/loadLibraryTest/libLoadLibraryClass.c

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2020, 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.
+ */
+
+/*
+ * Native test for LoadLibraryTest.
+ */
+
+#include "jni.h"
+
+JNIEXPORT void JNICALL Java_LoadLibraryClass_nTest(JNIEnv* env, jclass jclazz) { }