1 /*
2 * Copyright (c) 2015, 2025, 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.jrtfs;
26
27 import jdk.internal.jimage.ImageReader.Node;
28
29 import java.io.IOException;
30 import java.io.UncheckedIOException;
31 import java.nio.file.DirectoryStream;
32 import java.nio.file.FileSystemException;
33 import java.nio.file.Files;
34 import java.nio.file.Path;
35 import java.nio.file.Paths;
36 import java.nio.file.attribute.BasicFileAttributes;
37 import java.util.ArrayList;
38 import java.util.HashMap;
39 import java.util.HashSet;
40 import java.util.List;
41 import java.util.Map;
42 import java.util.Objects;
43 import java.util.Set;
44 import java.util.regex.Pattern;
45 import java.util.stream.Stream;
46
47 import static java.util.stream.Collectors.toList;
48
49 /**
50 * A jrt file system built on $JAVA_HOME/modules directory ('exploded modules
51 * build')
52 *
53 * @implNote This class needs to maintain JDK 8 source compatibility.
54 *
55 * It is used internally in the JDK to implement jimage/jrtfs access,
56 * but also compiled and delivered as part of the jrtfs.jar to support access
57 * to the jimage file provided by the shipped JDK by tools running on JDK 8.
58 */
59 class ExplodedImage extends SystemImage {
60
61 private static final String MODULES = "/modules/";
62 private static final String PACKAGES = "/packages/";
63 private static final Path META_INF_DIR = Paths.get("META-INF");
64 private static final Path PREVIEW_DIR = META_INF_DIR.resolve("preview");
65
66 private final Path modulesDir;
67 private final boolean isPreviewMode;
68 private final String separator;
69 private final Map<String, PathNode> nodes = new HashMap<>();
70 private final BasicFileAttributes modulesDirAttrs;
71
72 ExplodedImage(Path modulesDir, boolean isPreviewMode) throws IOException {
73 this.modulesDir = modulesDir;
74 this.isPreviewMode = isPreviewMode;
75 String str = modulesDir.getFileSystem().getSeparator();
76 separator = str.equals("/") ? null : str;
77 modulesDirAttrs = Files.readAttributes(modulesDir, BasicFileAttributes.class);
78 initNodes();
79 }
80
81 // A Node that is backed by actual default file system Path
82 private final class PathNode extends Node {
83 // Path in underlying default file system relative to modulesDir.
84 // In preview mode this need not correspond to the node's name.
85 private Path relPath;
86 private PathNode link;
87 private List<String> childNames;
88
89 /**
90 * Creates a file based node with the given file attributes.
91 *
92 * <p>If the underlying path is a directory, then it is created in an
93 * "incomplete" state, and its child names will be determined lazily.
94 */
95 private PathNode(String name, Path path, BasicFileAttributes attrs) { // path
96 super(name, attrs);
97 this.relPath = modulesDir.relativize(path);
98 if (relPath.isAbsolute() || relPath.getNameCount() == 0) {
99 throw new IllegalArgumentException("Invalid node path (must be relative): " + path);
100 }
101 }
102
103 /** Creates a symbolic link node to the specified target. */
104 private PathNode(String name, Node link) { // link
105 super(name, link.getFileAttributes());
106 this.link = (PathNode)link;
107 }
108
109 /** Creates a completed directory node based a list of child nodes. */
110 private PathNode(String name, List<PathNode> children) { // dir
111 super(name, modulesDirAttrs);
112 this.childNames = children.stream().map(Node::getName).collect(toList());
113 }
114
115 @Override
116 public boolean isResource() {
117 return link == null && !getFileAttributes().isDirectory();
118 }
119
120 @Override
121 public boolean isDirectory() {
122 return childNames != null ||
123 (link == null && getFileAttributes().isDirectory());
124 }
125
126 @Override
127 public boolean isLink() {
128 return link != null;
129 }
130
131 @Override
132 public PathNode resolveLink(boolean recursive) {
133 if (link == null)
134 return this;
135 return recursive && link.isLink() ? link.resolveLink(true) : link;
136 }
137
138 private byte[] getContent() throws IOException {
139 if (!getFileAttributes().isRegularFile())
140 throw new FileSystemException(getName() + " is not file");
141 return Files.readAllBytes(modulesDir.resolve(relPath));
142 }
143
144 @Override
145 public Stream<String> getChildNames() {
146 if (!isDirectory())
147 throw new IllegalStateException("not a directory: " + getName());
148 List<String> names = childNames;
149 if (names == null) {
150 names = completeDirectory();
151 }
152 return names.stream();
153 }
154
155 private synchronized List<String> completeDirectory() {
156 if (childNames != null) {
157 return childNames;
158 }
159 // Process preview nodes first, so if nodes are created they take
160 // precedence in the cache.
161 Set<String> childNameSet = new HashSet<>();
162 if (isPreviewMode && relPath.getNameCount() > 1 && !relPath.getName(1).equals(META_INF_DIR)) {
163 Path absPreviewDir = modulesDir
164 .resolve(relPath.getName(0))
165 .resolve(PREVIEW_DIR)
166 .resolve(relPath.subpath(1, relPath.getNameCount()));
167 if (Files.exists(absPreviewDir)) {
168 collectChildNodeNames(absPreviewDir, childNameSet);
169 }
170 }
171 collectChildNodeNames(modulesDir.resolve(relPath), childNameSet);
172 return childNames = childNameSet.stream().sorted().collect(toList());
173 }
174
175 private void collectChildNodeNames(Path absPath, Set<String> childNameSet) {
176 try (DirectoryStream<Path> stream = Files.newDirectoryStream(absPath)) {
177 for (Path p : stream) {
178 PathNode node = (PathNode) findNode(getName() + "/" + p.getFileName().toString());
179 if (node != null) { // findNode may choose to hide certain files!
180 childNameSet.add(node.getName());
181 }
182 }
183 } catch (IOException ex) {
184 throw new UncheckedIOException(ex);
185 }
186 }
187
188 @Override
189 public long size() {
190 try {
191 return isDirectory() ? 0 : Files.size(modulesDir.resolve(relPath));
192 } catch (IOException ex) {
193 throw new UncheckedIOException(ex);
194 }
195 }
196 }
197
198 @Override
199 public synchronized void close() throws IOException {
200 nodes.clear();
201 }
202
203 @Override
204 public byte[] getResource(Node node) throws IOException {
205 return ((PathNode)node).getContent();
206 }
207
208 @Override
209 public synchronized Node findNode(String name) {
210 PathNode node = nodes.get(name);
211 if (node != null) {
212 return node;
213 }
214 // If null, this was not the name of "/modules/..." node, and since all
215 // "/packages/..." nodes were created and cached in advance, the name
216 // cannot reference a valid node.
217 Path path = underlyingModulesPath(name);
218 if (path == null) {
219 return null;
220 }
221 // This can still return null for hidden files.
222 return createModulesNode(name, path);
223 }
224
225 /**
226 * Returns the expected file path for name in the "/modules/..." namespace,
227 * or {@code null} if the name is not in the "/modules/..." namespace or the
228 * path does not reference a file.
229 */
230 private Path underlyingModulesPath(String name) {
231 if (!isNonEmptyModulesName(name)) {
232 return null;
233 }
234 String relName = name.substring(MODULES.length());
235 Path relPath = Paths.get(frontSlashToNativeSlash(relName));
236 // The first path segment must exist due to check above.
237 Path modDir = relPath.getName(0);
238 Path previewDir = modDir.resolve(PREVIEW_DIR);
239 if (relPath.startsWith(previewDir)) {
240 return null;
241 }
242 Path path = modulesDir.resolve(relPath);
243 // Non-preview directories take precedence.
244 if (Files.isDirectory(path)) {
245 return path;
246 }
247 // Otherwise prefer preview resources over non-preview ones.
248 if (isPreviewMode
249 && relPath.getNameCount() > 1
250 && !modDir.equals(META_INF_DIR)) {
251 Path previewPath = modulesDir
252 .resolve(previewDir)
253 .resolve(relPath.subpath(1, relPath.getNameCount()));
254 if (Files.exists(previewPath)) {
255 return previewPath;
256 }
257 }
258 return Files.exists(path) ? path : null;
259 }
260
261 /**
262 * Lazily creates and caches a {@code Node} for the given "/modules/..." name
263 * and corresponding path to a file or directory.
264 *
265 * @param name a resource or directory node name, of the form "/modules/...".
266 * @param path the path of a file for a resource or directory.
267 * @return the newly created and cached node, or {@code null} if the given
268 * path references a file which must be hidden in the node hierarchy.
269 */
270 private PathNode createModulesNode(String name, Path path) {
271 assert !nodes.containsKey(name) : "Node must not already exist: " + name;
272 assert isNonEmptyModulesName(name) : "Invalid modules name: " + name;
273
274 try {
275 // We only know if we're creating a resource of directory when we
276 // look up file attributes, and we only do that once. Thus, we can
277 // only reject "marker files" here, rather than by inspecting the
278 // given name string, since it doesn't apply to directories.
279 BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
280 if (attrs.isRegularFile()) {
281 Path f = path.getFileName();
282 if (f.toString().startsWith("_the.")) {
283 return null;
284 }
285 } else if (!attrs.isDirectory()) {
286 return null;
287 }
288 PathNode node = new PathNode(name, path, attrs);
289 nodes.put(name, node);
290 return node;
291 } catch (IOException x) {
292 // Since the path references a file errors should not be ignored.
293 throw new UncheckedIOException(x);
294 }
295 }
296
297 private static final Pattern NON_EMPTY_MODULES_NAME =
298 Pattern.compile("/modules(/[^/]+)+");
299
300 private static boolean isNonEmptyModulesName(String name) {
301 // Don't just check the prefix, there must be something after it too
302 // (otherwise you end up with an empty string after trimming).
303 // Also make sure we can't be tricked by "/modules//absolute/path" or
304 // "/modules/../../escaped/path"
305 return NON_EMPTY_MODULES_NAME.matcher(name).matches()
306 && !name.contains("/../")
307 && !name.contains("/./");
308 }
309
310 // convert "/" to platform path separator
311 private String frontSlashToNativeSlash(String str) {
312 return separator == null ? str : str.replace("/", separator);
313 }
314
315 // convert "/"s to "."s
316 private String slashesToDots(String str) {
317 return str.replace(separator != null ? separator : "/", ".");
318 }
319
320 // initialize file system Nodes
321 private void initNodes() throws IOException {
322 // same package prefix may exist in multiple modules. This Map
323 // is filled by walking "jdk modules" directory recursively!
324 Map<String, List<String>> packageToModules = new HashMap<>();
325 try (DirectoryStream<Path> stream = Files.newDirectoryStream(modulesDir)) {
326 for (Path moduleDir : stream) {
327 if (Files.isDirectory(moduleDir)) {
328 processModuleDirectory(moduleDir, packageToModules);
329 }
330 }
331 }
332 // create "/modules" directory
333 // "nodes" map contains only /modules/<foo> nodes only so far and so add all as children of /modules
334 PathNode modulesRootNode = new PathNode("/modules", new ArrayList<>(nodes.values()));
335 nodes.put(modulesRootNode.getName(), modulesRootNode);
336
337 // create children under "/packages"
338 List<PathNode> packagesChildren = new ArrayList<>(packageToModules.size());
339 for (Map.Entry<String, List<String>> entry : packageToModules.entrySet()) {
340 String pkgName = entry.getKey();
341 List<String> moduleNameList = entry.getValue();
342 List<PathNode> moduleLinkNodes = new ArrayList<>(moduleNameList.size());
343 for (String moduleName : moduleNameList) {
344 Node moduleNode = Objects.requireNonNull(nodes.get(MODULES + moduleName));
345 PathNode linkNode = new PathNode(PACKAGES + pkgName + "/" + moduleName, moduleNode);
346 nodes.put(linkNode.getName(), linkNode);
347 moduleLinkNodes.add(linkNode);
348 }
349 PathNode pkgDir = new PathNode(PACKAGES + pkgName, moduleLinkNodes);
350 nodes.put(pkgDir.getName(), pkgDir);
351 packagesChildren.add(pkgDir);
352 }
353 // "/packages" dir
354 PathNode packagesRootNode = new PathNode("/packages", packagesChildren);
355 nodes.put(packagesRootNode.getName(), packagesRootNode);
356
357 // finally "/" dir!
358 List<PathNode> rootChildren = new ArrayList<>();
359 rootChildren.add(packagesRootNode);
360 rootChildren.add(modulesRootNode);
361 PathNode root = new PathNode("/", rootChildren);
362 nodes.put(root.getName(), root);
363 }
364
365 private void processModuleDirectory(Path moduleDir, Map<String, List<String>> packageToModules)
366 throws IOException {
367 String moduleName = moduleDir.getFileName().toString();
368 // Make sure "/modules/<moduleName>" is created
369 Objects.requireNonNull(createModulesNode(MODULES + moduleName, moduleDir));
370 // Skip the first path (it's always the given root directory).
371 try (Stream<Path> contentsStream = Files.walk(moduleDir).skip(1)) {
372 contentsStream
373 // Non-empty relative directory paths inside each module.
374 .filter(Files::isDirectory)
375 .map(moduleDir::relativize)
376 // Map paths inside preview directory to non-preview versions.
377 .filter(p -> isPreviewMode || !p.startsWith(PREVIEW_DIR))
378 .map(p -> isPreviewSubpath(p) ? PREVIEW_DIR.relativize(p) : p)
379 // Ignore special META-INF directory (including preview directory itself).
380 .filter(p -> !p.startsWith(META_INF_DIR))
381 // Extract unique package names.
382 .map(p -> slashesToDots(p.toString()))
383 .distinct()
384 .forEach(pkgName ->
385 packageToModules
386 .computeIfAbsent(pkgName, k -> new ArrayList<>())
387 .add(moduleName));
388 }
389 }
390
391 private static boolean isPreviewSubpath(Path p) {
392 return p.startsWith(PREVIEW_DIR) && p.getNameCount() > PREVIEW_DIR.getNameCount();
393 }
394 }