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/*
* Copyright (c) 2022, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*/
package javac.internal.jimage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;
import java.nio.channels.FileChannel;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Objects;
import java.util.stream.IntStream;
import javac.internal.jimage.decompressor.Decompressor;
/**
* @implNote This class needs to maintain JDK 8 source compatibility.
*
* It is used internally in the JDK to implement jimage/jrtfs access,
* but also compiled and delivered as part of the jrtfs.jar to support access
* to the jimage file provided by the shipped JDK by tools running on JDK 8.
*/
public class BasicImageReader implements AutoCloseable {
@SuppressWarnings("removal")
private static boolean isSystemProperty(String key, String value, String def) {
// No lambdas during bootstrap
return AccessController.doPrivileged(
new PrivilegedAction() {
@Override
public Boolean run() {
return value.equals(System.getProperty(key, def));
}
});
}
static private final boolean IS_64_BIT =
isSystemProperty("sun.arch.data.model", "64", "32");
static private final boolean USE_JVM_MAP =
isSystemProperty("jdk.image.use.jvm.map", "true", "true");
static private final boolean MAP_ALL =
isSystemProperty("jdk.image.map.all", "true", IS_64_BIT ? "true" : "false");
private final Path imagePath;
private final ByteOrder byteOrder;
private final String name;
private final ByteBuffer memoryMap;
private final FileChannel channel;
private final ImageHeader header;
private final long indexSize;
private final IntBuffer redirect;
private final IntBuffer offsets;
private final ByteBuffer locations;
private final ByteBuffer strings;
private final ImageStringsReader stringsReader;
private final Decompressor decompressor;
@SuppressWarnings("removal")
protected BasicImageReader(Path path, ByteOrder byteOrder)
throws IOException {
this.imagePath = Objects.requireNonNull(path);
this.byteOrder = Objects.requireNonNull(byteOrder);
this.name = this.imagePath.toString();
ByteBuffer map;
if (USE_JVM_MAP && BasicImageReader.class.getClassLoader() == null) {
// Check to see if the jvm has opened the file using libjimage
// native entry when loading the image for this runtime
map = NativeImageBuffer.getNativeMap(name);
} else {
map = null;
}
// Open the file only if no memory map yet or is 32 bit jvm
if (map != null && MAP_ALL) {
channel = null;
} else {
channel = FileChannel.open(imagePath, StandardOpenOption.READ);
// No lambdas during bootstrap
AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Void run() {
if (BasicImageReader.class.getClassLoader() == null) {
try {
Class fileChannelImpl =
Class.forName("sun.nio.ch.FileChannelImpl");
Method setUninterruptible =
fileChannelImpl.getMethod("setUninterruptible");
setUninterruptible.invoke(channel);
} catch (ClassNotFoundException |
NoSuchMethodException |
IllegalAccessException |
InvocationTargetException ex) {
// fall thru - will only happen on JDK-8 systems where this code
// is only used by tools using jrt-fs (non-critical.)
}
}
return null;
}
});
}
// If no memory map yet and 64 bit jvm then memory map entire file
if (MAP_ALL && map == null) {
map = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
}
// Assume we have a memory map to read image file header
ByteBuffer headerBuffer = map;
int headerSize = ImageHeader.getHeaderSize();
// If no memory map then read header from image file
if (headerBuffer == null) {
headerBuffer = ByteBuffer.allocateDirect(headerSize);
if (channel.read(headerBuffer, 0L) == headerSize) {
headerBuffer.rewind();
} else {
throw new IOException("\"" + name + "\" is not an image file");
}
} else if (headerBuffer.capacity() < headerSize) {
throw new IOException("\"" + name + "\" is not an image file");
}
// Interpret the image file header
header = readHeader(intBuffer(headerBuffer, 0, headerSize));
indexSize = header.getIndexSize();
// If no memory map yet then must be 32 bit jvm not previously mapped
if (map == null) {
// Just map the image index
map = channel.map(FileChannel.MapMode.READ_ONLY, 0, indexSize);
}
memoryMap = map.asReadOnlyBuffer();
// Interpret the image index
if (memoryMap.capacity() < indexSize) {
throw new IOException("The image file \"" + name + "\" is corrupted");
}
redirect = intBuffer(memoryMap, header.getRedirectOffset(), header.getRedirectSize());
offsets = intBuffer(memoryMap, header.getOffsetsOffset(), header.getOffsetsSize());
locations = slice(memoryMap, header.getLocationsOffset(), header.getLocationsSize());
strings = slice(memoryMap, header.getStringsOffset(), header.getStringsSize());
stringsReader = new ImageStringsReader(this);
decompressor = new Decompressor();
}
protected BasicImageReader(Path imagePath) throws IOException {
this(imagePath, ByteOrder.nativeOrder());
}
public static BasicImageReader open(Path imagePath) throws IOException {
return new BasicImageReader(imagePath, ByteOrder.nativeOrder());
}
public ImageHeader getHeader() {
return header;
}
private ImageHeader readHeader(IntBuffer buffer) throws IOException {
ImageHeader result = ImageHeader.readFrom(buffer);
if (result.getMagic() != ImageHeader.MAGIC) {
throw new IOException("\"" + name + "\" is not an image file");
}
if (result.getMajorVersion() != ImageHeader.MAJOR_VERSION ||
result.getMinorVersion() != ImageHeader.MINOR_VERSION) {
throw new IOException("The image file \"" + name + "\" is not " +
"the correct version. Major: " + result.getMajorVersion() +
". Minor: " + result.getMinorVersion());
}
return result;
}
private static ByteBuffer slice(ByteBuffer buffer, int position, int capacity) {
// Note that this is the only limit and position manipulation of
// BasicImageReader private ByteBuffers. The synchronize could be avoided
// by cloning the buffer to make a local copy, but at the cost of creating
// a new object.
synchronized(buffer) {
buffer.limit(position + capacity);
buffer.position(position);
return buffer.slice();
}
}
private IntBuffer intBuffer(ByteBuffer buffer, int offset, int size) {
return slice(buffer, offset, size).order(byteOrder).asIntBuffer();
}
public static void releaseByteBuffer(ByteBuffer buffer) {
Objects.requireNonNull(buffer);
if (!MAP_ALL) {
ImageBufferCache.releaseBuffer(buffer);
}
}
public String getName() {
return name;
}
public ByteOrder getByteOrder() {
return byteOrder;
}
public Path getImagePath() {
return imagePath;
}
@Override
public void close() throws IOException {
if (channel != null) {
channel.close();
}
}
public ImageStringsReader getStrings() {
return stringsReader;
}
public ImageLocation findLocation(String module, String name) {
int index = getLocationIndex(module, name);
if (index < 0) {
return null;
}
long[] attributes = getAttributes(offsets.get(index));
if (!ImageLocation.verify(module, name, attributes, stringsReader)) {
return null;
}
return new ImageLocation(attributes, stringsReader);
}
public ImageLocation findLocation(String name) {
int index = getLocationIndex(name);
if (index < 0) {
return null;
}
long[] attributes = getAttributes(offsets.get(index));
if (!ImageLocation.verify(name, attributes, stringsReader)) {
return null;
}
return new ImageLocation(attributes, stringsReader);
}
public boolean verifyLocation(String module, String name) {
int index = getLocationIndex(module, name);
if (index < 0) {
return false;
}
int locationOffset = offsets.get(index);
return ImageLocation.verify(module, name, locations, locationOffset, stringsReader);
}
// Details of the algorithm used here can be found in
// jdk.tools.jlink.internal.PerfectHashBuilder.
public int getLocationIndex(String name) {
int count = header.getTableLength();
int index = redirect.get(ImageStringsReader.hashCode(name) % count);
if (index < 0) {
// index is twos complement of location attributes index.
return -index - 1;
} else if (index > 0) {
// index is hash seed needed to compute location attributes index.
return ImageStringsReader.hashCode(name, index) % count;
} else {
// No entry.
return -1;
}
}
private int getLocationIndex(String module, String name) {
int count = header.getTableLength();
int index = redirect.get(ImageStringsReader.hashCode(module, name) % count);
if (index < 0) {
// index is twos complement of location attributes index.
return -index - 1;
} else if (index > 0) {
// index is hash seed needed to compute location attributes index.
return ImageStringsReader.hashCode(module, name, index) % count;
} else {
// No entry.
return -1;
}
}
public String[] getEntryNames() {
int[] attributeOffsets = new int[offsets.capacity()];
offsets.get(attributeOffsets);
return IntStream.of(attributeOffsets)
.filter(o -> o != 0)
.mapToObj(o -> ImageLocation.readFrom(this, o).getFullName())
.sorted()
.toArray(String[]::new);
}
ImageLocation getLocation(int offset) {
return ImageLocation.readFrom(this, offset);
}
public long[] getAttributes(int offset) {
if (offset < 0 || offset >= locations.limit()) {
throw new IndexOutOfBoundsException("offset");
}
return ImageLocation.decompress(locations, offset);
}
public String getString(int offset) {
if (offset < 0 || offset >= strings.limit()) {
throw new IndexOutOfBoundsException("offset");
}
return ImageStringsReader.stringFromByteBuffer(strings, offset);
}
public int match(int offset, String string, int stringOffset) {
if (offset < 0 || offset >= strings.limit()) {
throw new IndexOutOfBoundsException("offset");
}
return ImageStringsReader.stringFromByteBufferMatches(strings, offset, string, stringOffset);
}
private byte[] getBufferBytes(ByteBuffer buffer) {
Objects.requireNonNull(buffer);
byte[] bytes = new byte[buffer.limit()];
buffer.get(bytes);
return bytes;
}
private ByteBuffer readBuffer(long offset, long size) {
if (offset < 0 || Integer.MAX_VALUE <= offset) {
throw new IndexOutOfBoundsException("Bad offset: " + offset);
}
if (size < 0 || Integer.MAX_VALUE <= size) {
throw new IndexOutOfBoundsException("Bad size: " + size);
}
if (MAP_ALL) {
ByteBuffer buffer = slice(memoryMap, (int)offset, (int)size);
buffer.order(ByteOrder.BIG_ENDIAN);
return buffer;
} else {
if (channel == null) {
throw new InternalError("Image file channel not open");
}
ByteBuffer buffer = ImageBufferCache.getBuffer(size);
int read;
try {
read = channel.read(buffer, offset);
buffer.rewind();
} catch (IOException ex) {
ImageBufferCache.releaseBuffer(buffer);
throw new RuntimeException(ex);
}
if (read != size) {
ImageBufferCache.releaseBuffer(buffer);
throw new RuntimeException("Short read: " + read +
" instead of " + size + " bytes");
}
return buffer;
}
}
public byte[] getResource(String name) {
Objects.requireNonNull(name);
ImageLocation location = findLocation(name);
return location != null ? getResource(location) : null;
}
public byte[] getResource(ImageLocation loc) {
ByteBuffer buffer = getResourceBuffer(loc);
if (buffer != null) {
byte[] bytes = getBufferBytes(buffer);
ImageBufferCache.releaseBuffer(buffer);
return bytes;
}
return null;
}
public ByteBuffer getResourceBuffer(ImageLocation loc) {
Objects.requireNonNull(loc);
long offset = loc.getContentOffset() + indexSize;
long compressedSize = loc.getCompressedSize();
long uncompressedSize = loc.getUncompressedSize();
if (compressedSize < 0 || Integer.MAX_VALUE < compressedSize) {
throw new IndexOutOfBoundsException(
"Bad compressed size: " + compressedSize);
}
if (uncompressedSize < 0 || Integer.MAX_VALUE < uncompressedSize) {
throw new IndexOutOfBoundsException(
"Bad uncompressed size: " + uncompressedSize);
}
if (compressedSize == 0) {
return readBuffer(offset, uncompressedSize);
} else {
ByteBuffer buffer = readBuffer(offset, compressedSize);
if (buffer != null) {
byte[] bytesIn = getBufferBytes(buffer);
ImageBufferCache.releaseBuffer(buffer);
byte[] bytesOut;
try {
bytesOut = decompressor.decompressResource(byteOrder,
(int strOffset) -> getString(strOffset), bytesIn);
} catch (IOException ex) {
throw new RuntimeException(ex);
}
return ByteBuffer.wrap(bytesOut);
}
}
return null;
}
public InputStream getResourceStream(ImageLocation loc) {
Objects.requireNonNull(loc);
byte[] bytes = getResource(loc);
return new ByteArrayInputStream(bytes);
}
}