1 /*
2 * Copyright (c) 2015, 2020, 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.net.MalformedURLException;
31 import java.net.URI;
32 import java.net.URL;
33 import java.nio.file.Files;
34 import java.nio.file.Path;
35 import java.security.AccessController;
36 import java.security.PrivilegedAction;
37 import java.util.Arrays;
38 import java.util.Enumeration;
39 import java.util.concurrent.ConcurrentHashMap;
40 import java.util.jar.JarInputStream;
41 import java.util.jar.Manifest;
42 import java.util.stream.Stream;
43
44 import jdk.internal.access.JavaLangAccess;
45 import jdk.internal.access.SharedSecrets;
46 import jdk.internal.module.Modules;
47 import jdk.internal.module.ServicesCatalog;
48 import jdk.internal.util.StaticProperty;
49
50 /**
51 * Find resources and packages in modules defined to the boot class loader or
52 * resources and packages on the "boot class path" specified via -Xbootclasspath/a.
53 */
54
55 public class BootLoader {
56 private BootLoader() { }
57
58 // The unnamed module for the boot loader
59 private static final Module UNNAMED_MODULE;
60 private static final String JAVA_HOME = StaticProperty.javaHome();
61
62 static {
63 UNNAMED_MODULE = SharedSecrets.getJavaLangAccess().defineUnnamedModule(null);
64 setBootLoaderUnnamedModule0(UNNAMED_MODULE);
65 }
66
67 // ServiceCatalog for the boot class loader
68 private static final ServicesCatalog SERVICES_CATALOG = ServicesCatalog.create();
69
70 // ClassLoaderValue map for the boot class loader
71 private static final ConcurrentHashMap<?, ?> CLASS_LOADER_VALUE_MAP
72 = new ConcurrentHashMap<>();
73
74 // native libraries loaded by the boot class loader
75 private static final NativeLibraries NATIVE_LIBS
76 = NativeLibraries.jniNativeLibraries(null);
77
78 /**
79 * Returns the unnamed module for the boot loader.
80 */
81 public static Module getUnnamedModule() {
82 return UNNAMED_MODULE;
83 }
84
85 /**
86 * Returns the ServiceCatalog for modules defined to the boot class loader.
87 */
88 public static ServicesCatalog getServicesCatalog() {
89 return SERVICES_CATALOG;
90 }
91
92 /**
93 * Returns the ClassLoaderValue map for the boot class loader.
94 */
95 public static ConcurrentHashMap<?, ?> getClassLoaderValueMap() {
96 return CLASS_LOADER_VALUE_MAP;
97 }
98
99 /**
100 * Returns NativeLibraries for the boot class loader.
101 */
102 public static NativeLibraries getNativeLibraries() {
103 return NATIVE_LIBS;
104 }
105
106 /**
107 * Returns {@code true} if there is a class path associated with the
108 * BootLoader.
109 */
110 public static boolean hasClassPath() {
111 return ClassLoaders.bootLoader().hasClassPath();
112 }
113
114 /**
115 * Registers a module with this class loader so that its classes
116 * (and resources) become visible via this class loader.
117 */
118 public static void loadModule(ModuleReference mref) {
119 ClassLoaders.bootLoader().loadModule(mref);
120 }
121
122 /**
123 * Loads the Class object with the given name defined to the boot loader.
124 */
125 public static Class<?> loadClassOrNull(String name) {
126 return ClassLoaders.bootLoader().loadClassOrNull(name);
127 }
128
129 /**
130 * Loads the Class object with the given name in the given module
131 * defined to the boot loader. Returns {@code null} if not found.
132 */
133 public static Class<?> loadClass(Module module, String name) {
134 Class<?> c = loadClassOrNull(name);
135 if (c != null && c.getModule() == module) {
136 return c;
137 } else {
138 return null;
139 }
140 }
141
142 /**
143 * Loads a native library from the system library path.
144 */
145 public static void loadLibrary(String name) {
146 if (System.getSecurityManager() == null) {
147 BootLoader.getNativeLibraries().loadLibrary(name);
148 } else {
149 AccessController.doPrivileged(new java.security.PrivilegedAction<>() {
150 public Void run() {
151 BootLoader.getNativeLibraries().loadLibrary(name);
152 return null;
153 }
154 });
155 }
156 }
157
158 /**
159 * Returns a URL to a resource in a module defined to the boot loader.
160 */
161 public static URL findResource(String mn, String name) throws IOException {
162 return ClassLoaders.bootLoader().findResource(mn, name);
163 }
164
165 /**
166 * Returns an input stream to a resource in a module defined to the
167 * boot loader.
168 */
169 public static InputStream findResourceAsStream(String mn, String name)
170 throws IOException
171 {
172 return ClassLoaders.bootLoader().findResourceAsStream(mn, name);
173 }
174
175 /**
176 * Returns the URL to the given resource in any of the modules
177 * defined to the boot loader and the boot class path.
178 */
179 public static URL findResource(String name) {
180 return ClassLoaders.bootLoader().findResource(name);
181 }
182
183 /**
184 * Returns an Iterator to iterate over the resources of the given name
185 * in any of the modules defined to the boot loader.
186 */
187 public static Enumeration<URL> findResources(String name) throws IOException {
188 return ClassLoaders.bootLoader().findResources(name);
189 }
190
191 /**
192 * Define a package for the given class to the boot loader, if not already
193 * defined.
194 */
195 public static Package definePackage(Class<?> c) {
196 return getDefinedPackage(c.getPackageName());
197 }
198
199 /**
200 * Returns the Package of the given name defined to the boot loader or null
201 * if the package has not been defined.
202 */
203 public static Package getDefinedPackage(String pn) {
204 Package pkg = ClassLoaders.bootLoader().getDefinedPackage(pn);
205 if (pkg == null) {
206 String location = getSystemPackageLocation(pn.replace('.', '/'));
207 if (location != null) {
208 pkg = PackageHelper.definePackage(pn.intern(), location);
209 }
210 }
211 return pkg;
212 }
213
214 /**
215 * Returns a stream of the packages defined to the boot loader.
216 */
217 public static Stream<Package> packages() {
218 return Arrays.stream(getSystemPackageNames())
219 .map(name -> getDefinedPackage(name.replace('/', '.')));
220 }
221
222 /**
223 * Helper class to define {@code Package} objects for packages in modules
224 * defined to the boot loader.
225 */
226 static class PackageHelper {
227 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
228
229 /**
230 * Define the {@code Package} with the given name. The specified
231 * location is a jrt URL to a named module in the run-time image,
232 * a file URL to a module in an exploded run-time image, or a file
233 * path to an entry on the boot class path (java agent Boot-Class-Path
234 * or -Xbootclasspath/a.
235 *
236 * <p> If the given location is a JAR file containing a manifest,
237 * the defined Package contains the versioning information from
238 * the manifest, if present.
239 *
240 * @param name package name
241 * @param location location where the package is (jrt URL or file URL
242 * for a named module in the run-time or exploded image;
243 * a file path for a package from -Xbootclasspath/a)
244 */
245 static Package definePackage(String name, String location) {
246 Module module = findModule(location);
247 if (module != null) {
248 // named module from runtime image or exploded module
249 if (name.isEmpty())
250 throw new InternalError("empty package in " + location);
251 return JLA.definePackage(ClassLoaders.bootLoader(), name, module);
252 }
253
254 // package in unnamed module (-Xbootclasspath/a)
255 URL url = toFileURL(location);
256 Manifest man = url != null ? getManifest(location) : null;
257
258 return ClassLoaders.bootLoader().defineOrCheckPackage(name, man, url);
259 }
260
261 /**
262 * Finds the module at the given location defined to the boot loader.
263 * The module is either in runtime image or exploded image.
264 * Otherwise this method returns null.
265 */
266 private static Module findModule(String location) {
267 String mn = null;
268 if (location.startsWith("jrt:/")) {
269 // named module in runtime image ("jrt:/".length() == 5)
270 mn = location.substring(5, location.length());
271 } else if (location.startsWith("file:/")) {
272 // named module in exploded image
273 Path path = Path.of(URI.create(location));
274 Path modulesDir = Path.of(JAVA_HOME, "modules");
275 if (path.startsWith(modulesDir)) {
276 mn = path.getFileName().toString();
277 }
278 }
279
280 // return the Module object for the module name. The Module may
281 // in the boot layer or a child layer for the case that the module
282 // is loaded into a running VM
283 if (mn != null) {
284 String name = mn;
285 return Modules.findLoadedModule(mn)
286 .orElseThrow(() -> new InternalError(name + " not loaded"));
287 } else {
288 return null;
289 }
290 }
291
292 /**
293 * Returns URL if the given location is a regular file path.
294 */
295 private static URL toFileURL(String location) {
296 return AccessController.doPrivileged(new PrivilegedAction<>() {
297 public URL run() {
298 Path path = Path.of(location);
299 if (Files.isRegularFile(path)) {
300 try {
301 return path.toUri().toURL();
302 } catch (MalformedURLException e) {}
303 }
304 return null;
305 }
306 });
307 }
308
309 /**
310 * Returns the Manifest if the given location is a JAR file
311 * containing a manifest.
312 */
313 private static Manifest getManifest(String location) {
314 return AccessController.doPrivileged(new PrivilegedAction<>() {
315 public Manifest run() {
316 Path jar = Path.of(location);
317 try (InputStream in = Files.newInputStream(jar);
318 JarInputStream jis = new JarInputStream(in, false)) {
319 return jis.getManifest();
320 } catch (IOException e) {
321 return null;
322 }
323 }
324 });
325 }
326 }
327
328 /**
329 * Returns an array of the binary name of the packages defined by
330 * the boot loader, in VM internal form (forward slashes instead of dot).
331 */
332 private static native String[] getSystemPackageNames();
333
334 /**
335 * Returns the location of the package of the given name, if
336 * defined by the boot loader; otherwise {@code null} is returned.
337 *
338 * The location may be a module from the runtime image or exploded image,
339 * or from the boot class append path (i.e. -Xbootclasspath/a or
340 * BOOT-CLASS-PATH attribute specified in java agent).
341 */
342 private static native String getSystemPackageLocation(String name);
343 private static native void setBootLoaderUnnamedModule0(Module module);
344 }