1 /*
2 * Copyright (c) 2015, 2016, 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
26 package jdk.internal.module;
27
28 import java.io.ByteArrayInputStream;
29 import java.io.IOException;
30 import java.io.InputStream;
31 import java.io.UncheckedIOException;
32 import java.lang.module.ModuleDescriptor;
33 import java.lang.module.ModuleFinder;
34 import java.lang.module.ModuleReader;
35 import java.lang.module.ModuleReference;
36 import java.net.URI;
37 import java.net.URLConnection;
38 import java.nio.ByteBuffer;
39 import java.util.ArrayDeque;
40 import java.util.Collections;
41 import java.util.Deque;
42 import java.util.HashMap;
43 import java.util.Iterator;
44 import java.util.Map;
45 import java.util.Map.Entry;
46 import java.util.Objects;
47 import java.util.Optional;
48 import java.util.Set;
49 import java.util.Spliterator;
50 import java.util.function.Consumer;
51 import java.util.function.Supplier;
52 import java.util.stream.Stream;
53 import java.util.stream.StreamSupport;
54
55 import jdk.internal.jimage.ImageLocation;
56 import jdk.internal.jimage.ImageReader;
57 import jdk.internal.jimage.ImageReaderFactory;
58 import jdk.internal.misc.JavaNetUriAccess;
59 import jdk.internal.misc.SharedSecrets;
60 import jdk.internal.module.ModuleHashes.HashSupplier;
61 import jdk.internal.perf.PerfCounter;
62
63 /**
64 * A {@code ModuleFinder} that finds modules that are linked into the
65 * run-time image.
66 *
67 * The modules linked into the run-time image are assumed to have the
68 * Packages attribute.
69 */
70
71 public class SystemModuleFinder implements ModuleFinder {
72
73 private static final JavaNetUriAccess JNUA = SharedSecrets.getJavaNetUriAccess();
74
75 private static final PerfCounter initTime
76 = PerfCounter.newPerfCounter("jdk.module.finder.jimage.initTime");
77 private static final PerfCounter moduleCount
78 = PerfCounter.newPerfCounter("jdk.module.finder.jimage.modules");
79 private static final PerfCounter packageCount
80 = PerfCounter.newPerfCounter("jdk.module.finder.jimage.packages");
81 private static final PerfCounter exportsCount
82 = PerfCounter.newPerfCounter("jdk.module.finder.jimage.exports");
83 // ImageReader used to access all modules in the image
84 private static final ImageReader imageReader;
85
86 // singleton finder to find modules in the run-time images
87 private static final SystemModuleFinder INSTANCE;
88
89 public static SystemModuleFinder getInstance() {
90 return INSTANCE;
91 }
92
93 /**
94 * For now, the module references are created eagerly on the assumption
95 * that service binding will require all modules to be located.
96 */
97 static {
98 long t0 = System.nanoTime();
99 imageReader = ImageReaderFactory.getImageReader();
100
101 INSTANCE = new SystemModuleFinder();
102
103 initTime.addElapsedTimeFrom(t0);
104 }
105
106 private static boolean isFastPathSupported() {
107 return SystemModules.MODULE_NAMES.length > 0;
108 }
109
110 private static String[] moduleNames() {
111 if (isFastPathSupported())
112 // module names recorded at link time
113 return SystemModules.MODULE_NAMES;
114
115 // this happens when java.base is patched with java.base
116 // from an exploded image
117 return imageReader.getModuleNames();
118 }
119
120 // the set of modules in the run-time image
121 private final Set<ModuleReference> modules;
122
123 // maps module name to module reference
124 private final Map<String, ModuleReference> nameToModule;
125
126 // module name to hashes
127 private final Map<String, byte[]> hashes;
128
129 private SystemModuleFinder() {
130 String[] names = moduleNames();
131 int n = names.length;
132 moduleCount.add(n);
133
134 // fastpath is enabled by default.
135 // It can be disabled for troubleshooting purpose.
136 boolean disabled =
137 System.getProperty("jdk.system.module.finder.disabledFastPath") != null;
138
139 ModuleDescriptor[] descriptors;
140 ModuleHashes[] recordedHashes;
141 ModuleResolution[] moduleResolutions;
142
143 // fast loading of ModuleDescriptor of system modules
144 if (isFastPathSupported() && !disabled) {
145 descriptors = SystemModules.descriptors();
146 recordedHashes = SystemModules.hashes();
147 moduleResolutions = SystemModules.moduleResolutions();
148 } else {
149 // if fast loading of ModuleDescriptors is disabled
150 // fallback to read module-info.class
151 descriptors = new ModuleDescriptor[n];
152 recordedHashes = new ModuleHashes[n];
153 moduleResolutions = new ModuleResolution[n];
154 for (int i = 0; i < names.length; i++) {
155 String mn = names[i];
156 ImageLocation loc = imageReader.findLocation(mn, "module-info.class");
157 ModuleInfo.Attributes attrs =
158 ModuleInfo.read(imageReader.getResourceBuffer(loc), null);
159 descriptors[i] = attrs.descriptor();
160 recordedHashes[i] = attrs.recordedHashes();
161 moduleResolutions[i] = attrs.moduleResolution();
162 }
163 }
164
165 Map<String, byte[]> hashes = null;
166 boolean secondSeen = false;
167 // record the hashes to build HashSupplier
168 for (ModuleHashes mh : recordedHashes) {
169 if (mh != null) {
170 // if only one module contain ModuleHashes, use it
171 if (hashes == null) {
172 hashes = mh.hashes();
173 } else {
174 if (!secondSeen) {
175 hashes = new HashMap<>(hashes);
176 secondSeen = true;
177 }
178 hashes.putAll(mh.hashes());
179 }
180 }
181 }
182 this.hashes = (hashes == null) ? Map.of() : hashes;
183
184 ModuleReference[] mods = new ModuleReference[n];
185
186 @SuppressWarnings(value = {"rawtypes", "unchecked"})
187 Entry<String, ModuleReference>[] map
188 = (Entry<String, ModuleReference>[])new Entry[n];
189
190 for (int i = 0; i < n; i++) {
191 ModuleDescriptor md = descriptors[i];
192
193 // create the ModuleReference
194 ModuleReference mref = toModuleReference(md,
195 recordedHashes[i],
196 hashSupplier(names[i]),
197 moduleResolutions[i]);
198 mods[i] = mref;
199 map[i] = Map.entry(names[i], mref);
200
201 // counters
202 packageCount.add(md.packages().size());
203 exportsCount.add(md.exports().size());
204 }
205
206 modules = Set.of(mods);
207 nameToModule = Map.ofEntries(map);
208 }
209
210 @Override
211 public Optional<ModuleReference> find(String name) {
212 Objects.requireNonNull(name);
213 return Optional.ofNullable(nameToModule.get(name));
214 }
215
216 @Override
217 public Set<ModuleReference> findAll() {
218 return modules;
219 }
220
221 private ModuleReference toModuleReference(ModuleDescriptor md,
222 ModuleHashes recordedHashes,
223 HashSupplier hasher,
224 ModuleResolution mres) {
225 String mn = md.name();
226 URI uri = JNUA.create("jrt", "/".concat(mn));
227
228 Supplier<ModuleReader> readerSupplier = new Supplier<>() {
229 @Override
230 public ModuleReader get() {
231 return new ImageModuleReader(mn, uri);
232 }
233 };
234
235 ModuleReference mref =
236 new ModuleReferenceImpl(md, uri, readerSupplier, null,
237 recordedHashes, hasher, mres);
238
239 // may need a reference to a patched module if --patch-module specified
240 mref = ModuleBootstrap.patcher().patchIfNeeded(mref);
241
242 return mref;
243 }
244
245 private HashSupplier hashSupplier(String name) {
246 if (!hashes.containsKey(name))
247 return null;
248
249 return new HashSupplier() {
250 @Override
251 public byte[] generate(String algorithm) {
252 return hashes.get(name);
253 }
254 };
255 }
256
257 /**
258 * A ModuleReader for reading resources from a module linked into the
259 * run-time image.
260 */
261 static class ImageModuleReader implements ModuleReader {
262 private final String module;
263 private volatile boolean closed;
264
265 /**
266 * If there is a security manager set then check permission to
267 * connect to the run-time image.
268 */
269 private static void checkPermissionToConnect(URI uri) {
270 SecurityManager sm = System.getSecurityManager();
271 if (sm != null) {
272 try {
273 URLConnection uc = uri.toURL().openConnection();
274 sm.checkPermission(uc.getPermission());
275 } catch (IOException ioe) {
276 throw new UncheckedIOException(ioe);
277 }
278 }
279 }
280
281 ImageModuleReader(String module, URI uri) {
282 checkPermissionToConnect(uri);
283 this.module = module;
284 }
285
286 /**
287 * Returns the ImageLocation for the given resource, {@code null}
288 * if not found.
289 */
290 private ImageLocation findImageLocation(String name) throws IOException {
291 Objects.requireNonNull(name);
292 if (closed)
293 throw new IOException("ModuleReader is closed");
294 if (imageReader != null) {
295 return imageReader.findLocation(module, name);
296 } else {
297 // not an images build
298 return null;
299 }
300 }
301
302 @Override
303 public Optional<URI> find(String name) throws IOException {
304 ImageLocation location = findImageLocation(name);
305 if (location != null) {
306 URI u = URI.create("jrt:/" + module + "/" + name);
307 return Optional.of(u);
308 } else {
309 return Optional.empty();
310 }
311 }
312
313 @Override
314 public Optional<InputStream> open(String name) throws IOException {
315 return read(name).map(this::toInputStream);
316 }
317
318 private InputStream toInputStream(ByteBuffer bb) { // ## -> ByteBuffer?
319 try {
320 int rem = bb.remaining();
321 byte[] bytes = new byte[rem];
322 bb.get(bytes);
323 return new ByteArrayInputStream(bytes);
324 } finally {
325 release(bb);
326 }
327 }
328
329 @Override
330 public Optional<ByteBuffer> read(String name) throws IOException {
331 ImageLocation location = findImageLocation(name);
332 if (location != null) {
333 return Optional.of(imageReader.getResourceBuffer(location));
334 } else {
335 return Optional.empty();
336 }
337 }
338
339 @Override
340 public void release(ByteBuffer bb) {
341 Objects.requireNonNull(bb);
342 ImageReader.releaseByteBuffer(bb);
343 }
344
345 @Override
346 public Stream<String> list() throws IOException {
347 if (closed)
348 throw new IOException("ModuleReader is closed");
349
350 Spliterator<String> s = new ModuleContentSpliterator(module);
351 return StreamSupport.stream(s, false);
352 }
353
354 @Override
355 public void close() {
356 // nothing else to do
357 closed = true;
358 }
359 }
360
361 /**
362 * A Spliterator for traversing the resources of a module linked into the
363 * run-time image.
364 */
365 static class ModuleContentSpliterator implements Spliterator<String> {
366 final String moduleRoot;
367 final Deque<ImageReader.Node> stack;
368 Iterator<ImageReader.Node> iterator;
369
370 ModuleContentSpliterator(String module) throws IOException {
371 moduleRoot = "/modules/" + module;
372 stack = new ArrayDeque<>();
373
374 // push the root node to the stack to get started
375 ImageReader.Node dir = imageReader.findNode(moduleRoot);
376 if (dir == null || !dir.isDirectory())
377 throw new IOException(moduleRoot + " not a directory");
378 stack.push(dir);
379 iterator = Collections.emptyIterator();
380 }
381
382 /**
383 * Returns the name of the next non-directory node or {@code null} if
384 * there are no remaining nodes to visit.
385 */
386 private String next() throws IOException {
387 for (;;) {
388 while (iterator.hasNext()) {
389 ImageReader.Node node = iterator.next();
390 String name = node.getName();
391 if (node.isDirectory()) {
392 // build node
393 ImageReader.Node dir = imageReader.findNode(name);
394 assert dir.isDirectory();
395 stack.push(dir);
396 } else {
397 // strip /modules/$MODULE/ prefix
398 return name.substring(moduleRoot.length() + 1);
399 }
400 }
401
402 if (stack.isEmpty()) {
403 return null;
404 } else {
405 ImageReader.Node dir = stack.poll();
406 assert dir.isDirectory();
407 iterator = dir.getChildren().iterator();
408 }
409 }
410 }
411
412 @Override
413 public boolean tryAdvance(Consumer<? super String> action) {
414 String next;
415 try {
416 next = next();
417 } catch (IOException ioe) {
418 throw new UncheckedIOException(ioe);
419 }
420 if (next != null) {
421 action.accept(next);
422 return true;
423 } else {
424 return false;
425 }
426 }
427
428 @Override
429 public Spliterator<String> trySplit() {
430 return null;
431 }
432
433 @Override
434 public int characteristics() {
435 return Spliterator.DISTINCT + Spliterator.NONNULL + Spliterator.IMMUTABLE;
436 }
437
438 @Override
439 public long estimateSize() {
440 return Long.MAX_VALUE;
441 }
442 }
443 }