137 lines
4.3 KiB
Java
137 lines
4.3 KiB
Java
/*
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* Copyright (c) 2024, 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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import java.lang.reflect.Field;
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import java.lang.reflect.Method;
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import java.nio.ByteBuffer;
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import sun.misc.Unsafe;
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/**
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* Launched by UnsafeMemoryAccessWarnings with a '+' delimited list of methods to invoke.
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*/
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@SuppressWarnings("removal")
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public class TryUnsafeMemoryAccess {
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private static final Unsafe UNSAFE;
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static {
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try {
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Field f = Unsafe.class.getDeclaredField("theUnsafe");
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f.setAccessible(true);
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UNSAFE = (Unsafe) f.get(null);
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} catch (Exception e) {
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throw new ExceptionInInitializerError(e);
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}
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}
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private static long address;
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private static long offset;
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static class TestClass {
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long value;
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TestClass(long value) {
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this.value = value;
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}
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}
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/**
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* The argument is a list of names of no-arg static methods in this class to invoke.
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* The names are separated with a '+'.
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*/
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public static void main(String[] args) throws Exception {
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String[] methodNames = args[0].split("\\+");
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for (String methodName : methodNames) {
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Method m = TryUnsafeMemoryAccess.class.getDeclaredMethod(methodName);
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try {
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m.invoke(null);
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} catch (Throwable e) {
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e.printStackTrace();
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}
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}
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}
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// a selection of Unsafe memory access methods to test
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static void allocateMemory() {
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address = UNSAFE.allocateMemory(100);
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}
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static void freeMemory() {
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if (address == 0)
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throw new RuntimeException("allocateMemory not called");
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UNSAFE.freeMemory(address);
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}
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static void objectFieldOffset() throws Exception {
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Field f = TestClass.class.getDeclaredField("value");
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offset = UNSAFE.objectFieldOffset(f);
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}
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static void getLong() {
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if (offset == 0)
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throw new RuntimeException("objectFieldOffset not called");
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var obj = new TestClass(99);
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long value = UNSAFE.getLong(obj, offset);
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if (value != 99) {
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throw new RuntimeException();
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}
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}
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static void putLong() {
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if (offset == 0)
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throw new RuntimeException("objectFieldOffset not called");
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var obj = new TestClass(0);
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UNSAFE.putLong(obj, offset, 99);
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if (obj.value != 99) {
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throw new RuntimeException();
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}
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}
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static void invokeCleaner() {
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var dbb = ByteBuffer.allocateDirect(1000);
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UNSAFE.invokeCleaner(dbb);
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}
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/**
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* Invoke Unsafe.allocateMemory reflectively.
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*/
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static void reflectivelyAllocateMemory() throws Exception {
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Method allocateMemory = Unsafe.class.getMethod("allocateMemory", long.class);
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address = (long) allocateMemory.invoke(UNSAFE, 100);
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}
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/**
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* Invoke Unsafe.freeMemory reflectively.
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*/
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static void reflectivelyFreeMemory() throws Exception {
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if (address == 0)
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throw new RuntimeException("allocateMemory not called");
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Method freeMemory = Unsafe.class.getMethod("freeMemory", long.class);
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freeMemory.invoke(UNSAFE, address);
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}
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/**
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* Used to test that the property value from startup is used.
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*/
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static void setSystemPropertyToAllow() {
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System.setProperty("sun.misc.unsafe.memory.access", "allow");
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}
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}
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