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Bug 62151: Fix warnings about illegal reflective access in Java 9+ by 

using a similar approach as Apache Hadoop via a CleanerUtil class which encapsulates
the two different approaches for Java <= 8 and Java >= 9

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1854630 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Dominik Stadler 2019-03-02 09:19:45 +00:00
parent 421fffbd3f
commit 53a30d796e
2 changed files with 214 additions and 25 deletions
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201
src/java/org/apache/poi/poifs/nio/CleanerUtil.java Normal file
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@ -0,0 +1,201 @@
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==================================================================== */
package org.apache.poi.poifs.nio;
import org.apache.poi.util.SuppressForbidden;
import java.io.IOException;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Objects;
import static java.lang.invoke.MethodHandles.constant;
import static java.lang.invoke.MethodHandles.dropArguments;
import static java.lang.invoke.MethodHandles.filterReturnValue;
import static java.lang.invoke.MethodHandles.guardWithTest;
import static java.lang.invoke.MethodType.methodType;
/**
* This is taken from Hadoop at https://issues.apache.org/jira/browse/HADOOP-12760 and
* https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/CleanerUtil.java
* Unfortunately this is not available in some general utility library yet, but hopefully will be at some point.
*
* sun.misc.Cleaner has moved in OpenJDK 9 and
* sun.misc.Unsafe#invokeCleaner(ByteBuffer) is the replacement.
* This class is a hack to use sun.misc.Cleaner in Java 8 and
* use the replacement in Java 9+.
* This implementation is inspired by LUCENE-6989.
*/
public final class CleanerUtil {
// Prevent instantiation
private CleanerUtil(){}
/**
* <code>true</code>, if this platform supports unmapping mmapped files.
*/
public static final boolean UNMAP_SUPPORTED;
/**
* if {@link #UNMAP_SUPPORTED} is {@code false}, this contains the reason
* why unmapping is not supported.
*/
public static final String UNMAP_NOT_SUPPORTED_REASON;
private static final BufferCleaner CLEANER;
/**
* Reference to a BufferCleaner that does unmapping.
* @return {@code null} if not supported.
*/
public static BufferCleaner getCleaner() {
return CLEANER;
}
static {
final Object hack = AccessController.doPrivileged(
(PrivilegedAction<Object>) CleanerUtil::unmapHackImpl);
if (hack instanceof BufferCleaner) {
CLEANER = (BufferCleaner) hack;
UNMAP_SUPPORTED = true;
UNMAP_NOT_SUPPORTED_REASON = null;
} else {
CLEANER = null;
UNMAP_SUPPORTED = false;
UNMAP_NOT_SUPPORTED_REASON = hack.toString();
}
}
@SuppressForbidden("Java 9 Jigsaw whitelists access to sun.misc.Cleaner, so setAccessible works")
private static Object unmapHackImpl() {
final MethodHandles.Lookup lookup = MethodHandles.lookup();
try {
try {
// *** sun.misc.Unsafe unmapping (Java 9+) ***
final Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
// first check if Unsafe has the right method, otherwise we can
// give up without doing any security critical stuff:
final MethodHandle unmapper = lookup.findVirtual(unsafeClass,
"invokeCleaner", methodType(void.class, ByteBuffer.class));
// fetch the unsafe instance and bind it to the virtual MH:
final Field f = unsafeClass.getDeclaredField("theUnsafe");
f.setAccessible(true);
final Object theUnsafe = f.get(null);
return newBufferCleaner(ByteBuffer.class, unmapper.bindTo(theUnsafe));
} catch (SecurityException se) {
// rethrow to report errors correctly (we need to catch it here,
// as we also catch RuntimeException below!):
throw se;
} catch (ReflectiveOperationException | RuntimeException e) {
// *** sun.misc.Cleaner unmapping (Java 8) ***
final Class<?> directBufferClass =
Class.forName("java.nio.DirectByteBuffer");
final Method m = directBufferClass.getMethod("cleaner");
m.setAccessible(true);
final MethodHandle directBufferCleanerMethod = lookup.unreflect(m);
final Class<?> cleanerClass =
directBufferCleanerMethod.type().returnType();
/*
* "Compile" a MethodHandle that basically is equivalent
* to the following code:
*
* void unmapper(ByteBuffer byteBuffer) {
* sun.misc.Cleaner cleaner =
* ((java.nio.DirectByteBuffer) byteBuffer).cleaner();
* if (Objects.nonNull(cleaner)) {
* cleaner.clean();
* } else {
* // the noop is needed because MethodHandles#guardWithTest
* // always needs ELSE
* noop(cleaner);
* }
* }
*/
final MethodHandle cleanMethod = lookup.findVirtual(
cleanerClass, "clean", methodType(void.class));
final MethodHandle nonNullTest = lookup.findStatic(Objects.class,
"nonNull", methodType(boolean.class, Object.class))
.asType(methodType(boolean.class, cleanerClass));
final MethodHandle noop = dropArguments(
constant(Void.class, null).asType(methodType(void.class)),
0, cleanerClass);
final MethodHandle unmapper = filterReturnValue(
directBufferCleanerMethod,
guardWithTest(nonNullTest, cleanMethod, noop))
.asType(methodType(void.class, ByteBuffer.class));
return newBufferCleaner(directBufferClass, unmapper);
}
} catch (SecurityException se) {
return "Unmapping is not supported, because not all required " +
"permissions are given to the Hadoop JAR file: " + se +
" [Please grant at least the following permissions: " +
"RuntimePermission(\"accessClassInPackage.sun.misc\") " +
" and ReflectPermission(\"suppressAccessChecks\")]";
} catch (ReflectiveOperationException | RuntimeException e) {
return "Unmapping is not supported on this platform, " +
"because internal Java APIs are not compatible with " +
"this Hadoop version: " + e;
}
}
private static BufferCleaner newBufferCleaner(
final Class<?> unmappableBufferClass, final MethodHandle unmapper) {
assert Objects.equals(
methodType(void.class, ByteBuffer.class), unmapper.type());
return buffer -> {
if (!buffer.isDirect()) {
throw new IllegalArgumentException(
"unmapping only works with direct buffers");
}
if (!unmappableBufferClass.isInstance(buffer)) {
throw new IllegalArgumentException("buffer is not an instance of " +
unmappableBufferClass.getName());
}
final Throwable error = AccessController.doPrivileged(
(PrivilegedAction<Throwable>) () -> {
try {
unmapper.invokeExact(buffer);
return null;
} catch (Throwable t) {
return t;
}
});
if (error != null) {
throw new IOException("Unable to unmap the mapped buffer", error);
}
};
}
/**
* Pass in an implementation of this interface to cleanup ByteBuffers.
* CleanerUtil implements this to allow unmapping of bytebuffers
* with private Java APIs.
*/
@FunctionalInterface
public interface BufferCleaner {
void freeBuffer(ByteBuffer b) throws IOException;
}
}

32
src/java/org/apache/poi/poifs/nio/FileBackedDataSource.java
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@ -17,26 +17,22 @@
package org.apache.poi.poifs.nio;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.POILogFactory;
import org.apache.poi.util.POILogger;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.POILogFactory;
import org.apache.poi.util.POILogger;
import org.apache.poi.util.SuppressForbidden;
/**
* A POIFS {@link DataSource} backed by a File
*/
@ -171,22 +167,14 @@ public class FileBackedDataSource extends DataSource {
return;
}
AccessController.doPrivileged(new PrivilegedAction<Void>() {
@Override
@SuppressForbidden("Java 9 Jigsaw whitelists access to sun.misc.Cleaner, so setAccessible works")
public Void run() {
if (CleanerUtil.UNMAP_SUPPORTED) {
try {
final Method getCleanerMethod = buffer.getClass().getMethod("cleaner");
getCleanerMethod.setAccessible(true);
final Object cleaner = getCleanerMethod.invoke(buffer);
if (cleaner != null) {
cleaner.getClass().getMethod("clean").invoke(cleaner);
CleanerUtil.getCleaner().freeBuffer(buffer);
} catch (IOException e) {
logger.log(POILogger.WARN, "Failed to unmap the buffer", e);
}
} catch (Exception e) {
logger.log(POILogger.WARN, "Unable to unmap memory mapped ByteBuffer.", e);
} else {
logger.log(POILogger.DEBUG, CleanerUtil.UNMAP_NOT_SUPPORTED_REASON);
}
return null; // Void
}
});
}
}