1 /*
2 * Copyright (c) 2014, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package jdk.internal.jimage;
26
27 import java.io.ByteArrayInputStream;
28 import java.io.IOException;
29 import java.io.InputStream;
30 import java.lang.reflect.InvocationTargetException;
31 import java.lang.reflect.Method;
32 import java.nio.ByteBuffer;
33 import java.nio.ByteOrder;
34 import java.nio.IntBuffer;
35 import java.nio.channels.FileChannel;
36 import java.nio.file.Path;
37 import java.nio.file.StandardOpenOption;
38 import java.security.AccessController;
39 import java.security.PrivilegedAction;
40 import java.util.Objects;
41 import java.util.stream.IntStream;
42 import jdk.internal.jimage.decompressor.Decompressor;
43
44 /**
45 * @implNote This class needs to maintain JDK 8 source compatibility.
46 *
47 * It is used internally in the JDK to implement jimage/jrtfs access,
48 * but also compiled and delivered as part of the jrtfs.jar to support access
49 * to the jimage file provided by the shipped JDK by tools running on JDK 8.
50 */
51 public class BasicImageReader implements AutoCloseable {
52 private static boolean isSystemProperty(String key, String value, String def) {
53 // No lambdas during bootstrap
54 return AccessController.doPrivileged(
55 new PrivilegedAction<Boolean>() {
56 @Override
57 public Boolean run() {
58 return value.equals(System.getProperty(key, def));
59 }
60 });
61 }
62
63 static private final boolean IS_64_BIT =
64 isSystemProperty("sun.arch.data.model", "64", "32");
65 static private final boolean USE_JVM_MAP =
66 isSystemProperty("jdk.image.use.jvm.map", "true", "true");
67 static private final boolean MAP_ALL =
68 isSystemProperty("jdk.image.map.all", "true", IS_64_BIT ? "true" : "false");
69
70 private final Path imagePath;
71 private final ByteOrder byteOrder;
72 private final String name;
73 private final ByteBuffer memoryMap;
74 private final FileChannel channel;
75 private final ImageHeader header;
76 private final long indexSize;
77 private final IntBuffer redirect;
78 private final IntBuffer offsets;
79 private final ByteBuffer locations;
80 private final ByteBuffer strings;
81 private final ImageStringsReader stringsReader;
82 private final Decompressor decompressor;
83
84 protected BasicImageReader(Path path, ByteOrder byteOrder)
85 throws IOException {
86 this.imagePath = Objects.requireNonNull(path);
87 this.byteOrder = Objects.requireNonNull(byteOrder);
88 this.name = this.imagePath.toString();
89
90 ByteBuffer map;
91
92 if (USE_JVM_MAP && BasicImageReader.class.getClassLoader() == null) {
93 // Check to see if the jvm has opened the file using libjimage
94 // native entry when loading the image for this runtime
95 map = NativeImageBuffer.getNativeMap(name);
96 } else {
97 map = null;
98 }
99
100 // Open the file only if no memory map yet or is 32 bit jvm
101 if (map != null && MAP_ALL) {
102 channel = null;
103 } else {
104 channel = FileChannel.open(imagePath, StandardOpenOption.READ);
105 // No lambdas during bootstrap
106 AccessController.doPrivileged(new PrivilegedAction<Void>() {
107 @Override
108 public Void run() {
109 if (BasicImageReader.class.getClassLoader() == null) {
110 try {
111 Class<?> fileChannelImpl =
112 Class.forName("sun.nio.ch.FileChannelImpl");
113 Method setUninterruptible =
114 fileChannelImpl.getMethod("setUninterruptible");
115 setUninterruptible.invoke(channel);
116 } catch (ClassNotFoundException |
117 NoSuchMethodException |
118 IllegalAccessException |
119 InvocationTargetException ex) {
120 // fall thru - will only happen on JDK-8 systems where this code
121 // is only used by tools using jrt-fs (non-critical.)
122 }
123 }
124
125 return null;
126 }
127 });
128 }
129
130 // If no memory map yet and 64 bit jvm then memory map entire file
131 if (MAP_ALL && map == null) {
132 map = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
133 }
134
135 // Assume we have a memory map to read image file header
136 ByteBuffer headerBuffer = map;
137 int headerSize = ImageHeader.getHeaderSize();
138
139 // If no memory map then read header from image file
140 if (headerBuffer == null) {
141 headerBuffer = ByteBuffer.allocateDirect(headerSize);
142 if (channel.read(headerBuffer, 0L) == headerSize) {
143 headerBuffer.rewind();
144 } else {
145 throw new IOException("\"" + name + "\" is not an image file");
146 }
147 } else if (headerBuffer.capacity() < headerSize) {
148 throw new IOException("\"" + name + "\" is not an image file");
149 }
150
151 // Interpret the image file header
152 header = readHeader(intBuffer(headerBuffer, 0, headerSize));
153 indexSize = header.getIndexSize();
154
155 // If no memory map yet then must be 32 bit jvm not previously mapped
156 if (map == null) {
157 // Just map the image index
158 map = channel.map(FileChannel.MapMode.READ_ONLY, 0, indexSize);
159 }
160
161 memoryMap = map.asReadOnlyBuffer();
162
163 // Interpret the image index
164 if (memoryMap.capacity() < indexSize) {
165 throw new IOException("The image file \"" + name + "\" is corrupted");
166 }
167 redirect = intBuffer(memoryMap, header.getRedirectOffset(), header.getRedirectSize());
168 offsets = intBuffer(memoryMap, header.getOffsetsOffset(), header.getOffsetsSize());
169 locations = slice(memoryMap, header.getLocationsOffset(), header.getLocationsSize());
170 strings = slice(memoryMap, header.getStringsOffset(), header.getStringsSize());
171
172 stringsReader = new ImageStringsReader(this);
173 decompressor = new Decompressor();
174 }
175
176 protected BasicImageReader(Path imagePath) throws IOException {
177 this(imagePath, ByteOrder.nativeOrder());
178 }
179
180 public static BasicImageReader open(Path imagePath) throws IOException {
181 return new BasicImageReader(imagePath, ByteOrder.nativeOrder());
182 }
183
184 public ImageHeader getHeader() {
185 return header;
186 }
187
188 private ImageHeader readHeader(IntBuffer buffer) throws IOException {
189 ImageHeader result = ImageHeader.readFrom(buffer);
190
191 if (result.getMagic() != ImageHeader.MAGIC) {
192 throw new IOException("\"" + name + "\" is not an image file");
193 }
194
195 if (result.getMajorVersion() != ImageHeader.MAJOR_VERSION ||
196 result.getMinorVersion() != ImageHeader.MINOR_VERSION) {
197 throw new IOException("The image file \"" + name + "\" is not " +
198 "the correct version. Major: " + result.getMajorVersion() +
199 ". Minor: " + result.getMinorVersion());
200 }
201
202 return result;
203 }
204
205 private static ByteBuffer slice(ByteBuffer buffer, int position, int capacity) {
206 // Note that this is the only limit and position manipulation of
207 // BasicImageReader private ByteBuffers. The synchronize could be avoided
208 // by cloning the buffer to make a local copy, but at the cost of creating
209 // a new object.
210 synchronized(buffer) {
211 buffer.limit(position + capacity);
212 buffer.position(position);
213 return buffer.slice();
214 }
215 }
216
217 private IntBuffer intBuffer(ByteBuffer buffer, int offset, int size) {
218 return slice(buffer, offset, size).order(byteOrder).asIntBuffer();
219 }
220
221 public static void releaseByteBuffer(ByteBuffer buffer) {
222 Objects.requireNonNull(buffer);
223
224 if (!MAP_ALL) {
225 ImageBufferCache.releaseBuffer(buffer);
226 }
227 }
228
229 public String getName() {
230 return name;
231 }
232
233 public ByteOrder getByteOrder() {
234 return byteOrder;
235 }
236
237 public Path getImagePath() {
238 return imagePath;
239 }
240
241 @Override
242 public void close() throws IOException {
243 if (channel != null) {
244 channel.close();
245 }
246 }
247
248 public ImageStringsReader getStrings() {
249 return stringsReader;
250 }
251
252 public ImageLocation findLocation(String mn, String rn) {
253 Objects.requireNonNull(mn);
254 Objects.requireNonNull(rn);
255
256 return findLocation("/" + mn + "/" + rn);
257 }
258
259 public synchronized ImageLocation findLocation(String name) {
260 Objects.requireNonNull(name);
261 // Details of the algorithm used here can be found in
262 // jdk.tools.jlink.internal.PerfectHashBuilder.
263 int count = header.getTableLength();
264 int index = redirect.get(ImageStringsReader.hashCode(name) % count);
265
266 if (index < 0) {
267 // index is twos complement of location attributes index.
268 index = -index - 1;
269 } else if (index > 0) {
270 // index is hash seed needed to compute location attributes index.
271 index = ImageStringsReader.hashCode(name, index) % count;
272 } else {
273 // No entry.
274 return null;
275 }
276
277 long[] attributes = getAttributes(offsets.get(index));
278
279 if (!ImageLocation.verify(name, attributes, stringsReader)) {
280 return null;
281 }
282 return new ImageLocation(attributes, stringsReader);
283 }
284
285 public String[] getEntryNames() {
286 int[] attributeOffsets = new int[offsets.capacity()];
287 offsets.get(attributeOffsets);
288 return IntStream.of(attributeOffsets)
289 .filter(o -> o != 0)
290 .mapToObj(o -> ImageLocation.readFrom(this, o).getFullName())
291 .sorted()
292 .toArray(String[]::new);
293 }
294
295 ImageLocation getLocation(int offset) {
296 return ImageLocation.readFrom(this, offset);
297 }
298
299 public long[] getAttributes(int offset) {
300 if (offset < 0 || offset >= locations.limit()) {
301 throw new IndexOutOfBoundsException("offset");
302 }
303
304 ByteBuffer buffer = slice(locations, offset, locations.limit() - offset);
305 return ImageLocation.decompress(buffer);
306 }
307
308 public String getString(int offset) {
309 if (offset < 0 || offset >= strings.limit()) {
310 throw new IndexOutOfBoundsException("offset");
311 }
312
313 ByteBuffer buffer = slice(strings, offset, strings.limit() - offset);
314 return ImageStringsReader.stringFromByteBuffer(buffer);
315 }
316
317 private byte[] getBufferBytes(ByteBuffer buffer) {
318 Objects.requireNonNull(buffer);
319 byte[] bytes = new byte[buffer.limit()];
320 buffer.get(bytes);
321
322 return bytes;
323 }
324
325 private ByteBuffer readBuffer(long offset, long size) {
326 if (offset < 0 || Integer.MAX_VALUE <= offset) {
327 throw new IndexOutOfBoundsException("Bad offset: " + offset);
328 }
329
330 if (size < 0 || Integer.MAX_VALUE <= size) {
331 throw new IndexOutOfBoundsException("Bad size: " + size);
332 }
333
334 if (MAP_ALL) {
335 ByteBuffer buffer = slice(memoryMap, (int)offset, (int)size);
336 buffer.order(ByteOrder.BIG_ENDIAN);
337
338 return buffer;
339 } else {
340 if (channel == null) {
341 throw new InternalError("Image file channel not open");
342 }
343
344 ByteBuffer buffer = ImageBufferCache.getBuffer(size);
345 int read;
346 try {
347 read = channel.read(buffer, offset);
348 buffer.rewind();
349 } catch (IOException ex) {
350 ImageBufferCache.releaseBuffer(buffer);
351 throw new RuntimeException(ex);
352 }
353
354 if (read != size) {
355 ImageBufferCache.releaseBuffer(buffer);
356 throw new RuntimeException("Short read: " + read +
357 " instead of " + size + " bytes");
358 }
359
360 return buffer;
361 }
362 }
363
364 public byte[] getResource(String name) {
365 Objects.requireNonNull(name);
366 ImageLocation location = findLocation(name);
367
368 return location != null ? getResource(location) : null;
369 }
370
371 public byte[] getResource(ImageLocation loc) {
372 ByteBuffer buffer = getResourceBuffer(loc);
373
374 if (buffer != null) {
375 byte[] bytes = getBufferBytes(buffer);
376 ImageBufferCache.releaseBuffer(buffer);
377
378 return bytes;
379 }
380
381 return null;
382 }
383
384 public ByteBuffer getResourceBuffer(ImageLocation loc) {
385 Objects.requireNonNull(loc);
386 long offset = loc.getContentOffset() + indexSize;
387 long compressedSize = loc.getCompressedSize();
388 long uncompressedSize = loc.getUncompressedSize();
389
390 if (compressedSize < 0 || Integer.MAX_VALUE < compressedSize) {
391 throw new IndexOutOfBoundsException(
392 "Bad compressed size: " + compressedSize);
393 }
394
395 if (uncompressedSize < 0 || Integer.MAX_VALUE < uncompressedSize) {
396 throw new IndexOutOfBoundsException(
397 "Bad uncompressed size: " + uncompressedSize);
398 }
399
400 if (compressedSize == 0) {
401 return readBuffer(offset, uncompressedSize);
402 } else {
403 ByteBuffer buffer = readBuffer(offset, compressedSize);
404
405 if (buffer != null) {
406 byte[] bytesIn = getBufferBytes(buffer);
407 ImageBufferCache.releaseBuffer(buffer);
408 byte[] bytesOut;
409
410 try {
411 bytesOut = decompressor.decompressResource(byteOrder,
412 (int strOffset) -> getString(strOffset), bytesIn);
413 } catch (IOException ex) {
414 throw new RuntimeException(ex);
415 }
416
417 return ByteBuffer.wrap(bytesOut);
418 }
419 }
420
421 return null;
422 }
423
424 public InputStream getResourceStream(ImageLocation loc) {
425 Objects.requireNonNull(loc);
426 byte[] bytes = getResource(loc);
427
428 return new ByteArrayInputStream(bytes);
429 }
430 }