1 /*
2 * Copyright (c) 2015, 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.loader;
26
27 import java.io.IOException;
28 import java.io.InputStream;
29 import java.lang.module.ModuleReference;
30 import java.lang.reflect.Layer;
31 import java.lang.reflect.Module;
32 import java.net.MalformedURLException;
33 import java.net.URI;
34 import java.net.URL;
35 import java.nio.file.Files;
36 import java.nio.file.Path;
37 import java.nio.file.Paths;
38 import java.security.AccessController;
39 import java.security.PrivilegedAction;
40 import java.util.Arrays;
41 import java.util.Enumeration;
42 import java.util.Optional;
43 import java.util.concurrent.ConcurrentHashMap;
44 import java.util.jar.JarInputStream;
45 import java.util.jar.Manifest;
46 import java.util.stream.Stream;
47
48 import jdk.internal.misc.JavaLangAccess;
49 import jdk.internal.misc.SharedSecrets;
50 import jdk.internal.module.ServicesCatalog;
51
52 /**
53 * Find resources and packages in modules defined to the boot class loader or
54 * resources and packages on the "boot class path" specified via -Xbootclasspath/a.
55 */
56
57 public class BootLoader {
58 private BootLoader() { }
59
60 // The unnamed module for the boot loader
61 private static final Module UNNAMED_MODULE;
62 private static final String JAVA_HOME = System.getProperty("java.home");
63
64 static {
65 UNNAMED_MODULE
66 = SharedSecrets.getJavaLangReflectModuleAccess().defineUnnamedModule(null);
67 setBootLoaderUnnamedModule0(UNNAMED_MODULE);
68 }
69
70 // ServiceCatalog for the boot class loader
71 private static final ServicesCatalog SERVICES_CATALOG = new ServicesCatalog();
72
73 // ClassLoaderValue map for boot class loader
74 private static final ConcurrentHashMap<?, ?> CLASS_LOADER_VALUE_MAP =
75 new ConcurrentHashMap<>();
76
77 /**
78 * Returns the unnamed module for the boot loader.
79 */
80 public static Module getUnnamedModule() {
81 return UNNAMED_MODULE;
82 }
83
84 /**
85 * Returns the ServiceCatalog for modules defined to the boot class loader.
86 */
87 public static ServicesCatalog getServicesCatalog() {
88 return SERVICES_CATALOG;
89 }
90
91 /**
92 * Returns the ClassLoaderValue map for the boot class loader.
93 */
94 public static ConcurrentHashMap<?, ?> getClassLoaderValueMap() {
95 return CLASS_LOADER_VALUE_MAP;
96 }
97
98 /**
99 * Register a module with this class loader so that its classes (and
100 * resources) become visible via this class loader.
101 */
102 public static void loadModule(ModuleReference mref) {
103 ClassLoaders.bootLoader().loadModule(mref);
104 }
105
106 /**
107 * Loads the Class object with the given name defined to the boot loader.
108 */
109 public static Class<?> loadClassOrNull(String name) {
110 return ClassLoaders.bootLoader().loadClassOrNull(name);
111 }
112
113 /**
114 * Returns a URL to a resource in a named module defined to the boot loader.
115 */
116 public static URL findResource(String mn, String name) throws IOException {
117 return ClassLoaders.bootLoader().findResource(mn, name);
118 }
119
120 /**
121 * Returns an input stream to a resource in a named module defined to the
122 * boot loader.
123 */
124 public static InputStream findResourceAsStream(String mn, String name)
125 throws IOException
126 {
127 return ClassLoaders.bootLoader().findResourceAsStream(mn, name);
128 }
129
130 /**
131 * Returns the URL to the given resource if the resource can be located
132 * on the boot class path. This method does not locate a resource in any
133 * of the named modules defined to the boot loader.
134 */
135 public static URL findResource(String name) {
136 return ClassLoaders.bootLoader().findResource(name);
137 }
138
139 /**
140 * Returns an Iterator to iterate over the resources of the given name
141 * on the boot class path. This method does not locate resources in any
142 * of the named modules defined to the boot loader.
143 */
144 public static Enumeration<URL> findResources(String name) throws IOException {
145 return ClassLoaders.bootLoader().findResources(name);
146 }
147
148 /**
149 * Define a package for the given class to the boot loader, if not already
150 * defined.
151 */
152 public static Package definePackage(Class<?> c) {
153 return getDefinedPackage(c.getPackageName());
154 }
155
156 /**
157 * Returns the Package of the given name defined to the boot loader or null
158 * if the package has not been defined.
159 */
160 public static Package getDefinedPackage(String pn) {
161 Package pkg = ClassLoaders.bootLoader().getDefinedPackage(pn);
162 if (pkg == null) {
163 String location = getSystemPackageLocation(pn.replace('.', '/'));
164 if (location != null) {
165 pkg = PackageHelper.definePackage(pn.intern(), location);
166 }
167 }
168 return pkg;
169 }
170
171 /**
172 * Returns a stream of the packages defined to the boot loader.
173 */
174 public static Stream<Package> packages() {
175 return Arrays.stream(getSystemPackageNames())
176 .map(name -> getDefinedPackage(name.replace('/', '.')));
177 }
178
179 /**
180 * Helper class to define {@code Package} objects for packages in modules
181 * defined to the boot loader.
182 */
183 static class PackageHelper {
184 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
185
186 /**
187 * Define the {@code Package} with the given name. The specified
188 * location is a jrt URL to a named module in the run-time image,
189 * a file URL to a module in an exploded run-time image, or a file
190 * path to an entry on the boot class path (java agent Boot-Class-Path
191 * or -Xbootclasspath/a.
192 *
193 * <p> If the given location is a JAR file containing a manifest,
194 * the defined Package contains the versioning information from
195 * the manifest, if present.
196 *
197 * @param name package name
198 * @param location location where the package is (jrt URL or file URL
199 * for a named module in the run-time or exploded image;
200 * a file path for a package from -Xbootclasspath/a)
201 */
202 static Package definePackage(String name, String location) {
203 Module module = findModule(location);
204 if (module != null) {
205 // named module from runtime image or exploded module
206 if (name.isEmpty())
207 throw new InternalError("empty package in " + location);
208 return JLA.definePackage(ClassLoaders.bootLoader(), name, module);
209 }
210
211 // package in unnamed module (-Xbootclasspath/a)
212 URL url = toFileURL(location);
213 Manifest man = url != null ? getManifest(location) : null;
214
215 return ClassLoaders.bootLoader().defineOrCheckPackage(name, man, url);
216 }
217
218 /**
219 * Finds the module at the given location defined to the boot loader.
220 * The module is either in runtime image or exploded image.
221 * Otherwise this method returns null.
222 */
223 private static Module findModule(String location) {
224 String mn = null;
225 if (location.startsWith("jrt:/")) {
226 // named module in runtime image ("jrt:/".length() == 5)
227 mn = location.substring(5, location.length());
228 } else if (location.startsWith("file:/")) {
229 // named module in exploded image
230 Path path = Paths.get(URI.create(location));
231 Path modulesDir = Paths.get(JAVA_HOME, "modules");
232 if (path.startsWith(modulesDir)) {
233 mn = path.getFileName().toString();
234 }
235 }
236
237 if (mn != null) {
238 // named module from runtime image or exploded module
239 Optional<Module> om = Layer.boot().findModule(mn);
240 if (!om.isPresent())
241 throw new InternalError(mn + " not in boot layer");
242 return om.getWhenPresent();
243 }
244
245 return null;
246 }
247
248 /**
249 * Returns URL if the given location is a regular file path.
250 */
251 private static URL toFileURL(String location) {
252 return AccessController.doPrivileged(new PrivilegedAction<>() {
253 public URL run() {
254 Path path = Paths.get(location);
255 if (Files.isRegularFile(path)) {
256 try {
257 return path.toUri().toURL();
258 } catch (MalformedURLException e) {}
259 }
260 return null;
261 }
262 });
263 }
264
265 /**
266 * Returns the Manifest if the given location is a JAR file
267 * containing a manifest.
268 */
269 private static Manifest getManifest(String location) {
270 return AccessController.doPrivileged(new PrivilegedAction<>() {
271 public Manifest run() {
272 Path jar = Paths.get(location);
273 try (InputStream in = Files.newInputStream(jar);
274 JarInputStream jis = new JarInputStream(in, false)) {
275 return jis.getManifest();
276 } catch (IOException e) {
277 return null;
278 }
279 }
280 });
281 }
282 }
283
284 /**
285 * Returns an array of the binary name of the packages defined by
286 * the boot loader, in VM internal form (forward slashes instead of dot).
287 */
288 private static native String[] getSystemPackageNames();
289
290 /**
291 * Returns the location of the package of the given name, if
292 * defined by the boot loader; otherwise {@code null} is returned.
293 *
294 * The location may be a module from the runtime image or exploded image,
295 * or from the boot class append path (i.e. -Xbootclasspath/a or
296 * BOOT-CLASS-PATH attribute specified in java agent).
297 */
298 private static native String getSystemPackageLocation(String name);
299 private static native void setBootLoaderUnnamedModule0(Module module);
300 }