1 /*
2 * Copyright (c) 2015, 2019, 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.PrintStream;
29 import java.lang.module.Configuration;
30 import java.lang.module.ModuleDescriptor;
31 import java.lang.module.ModuleFinder;
32 import java.lang.module.ModuleReference;
33 import java.lang.module.ResolvedModule;
34 import java.net.URI;
35 import java.security.AccessController;
36 import java.security.PrivilegedAction;
37 import java.util.Collection;
38 import java.util.List;
39 import java.util.Map;
40 import java.util.Optional;
41 import java.util.Set;
42 import java.util.function.Function;
43 import java.util.stream.Collectors;
44
45 import jdk.internal.access.JavaLangModuleAccess;
46 import jdk.internal.loader.BootLoader;
47 import jdk.internal.loader.BuiltinClassLoader;
48 import jdk.internal.loader.ClassLoaders;
49 import jdk.internal.access.JavaLangAccess;
50 import jdk.internal.access.SharedSecrets;
51
52 /**
53 * A helper class for creating and updating modules. This class is intended to
54 * support command-line options, tests, and the instrumentation API. It is also
55 * used by the VM to load modules or add read edges when agents are instrumenting
56 * code that need to link to supporting classes.
57 *
58 * The parameters that are package names in this API are the fully-qualified
59 * names of the packages as defined in section 6.5.3 of <cite>The Java™
60 * Language Specification </cite>, for example, {@code "java.lang"}.
61 */
62
63 public class Modules {
64 private Modules() { }
65
66 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
67 private static final JavaLangModuleAccess JLMA = SharedSecrets.getJavaLangModuleAccess();
68
69 /**
70 * Creates a new Module. The module has the given ModuleDescriptor and
71 * is defined to the given class loader.
72 *
73 * The resulting Module is in a larval state in that it does not read
74 * any other module and does not have any exports.
75 *
76 * The URI is for information purposes only.
77 */
78 public static Module defineModule(ClassLoader loader,
79 ModuleDescriptor descriptor,
80 URI uri)
81 {
82 return JLA.defineModule(loader, descriptor, uri);
83 }
84
85 /**
86 * Updates m1 to read m2.
87 * Same as m1.addReads(m2) but without a caller check.
88 */
89 public static void addReads(Module m1, Module m2) {
90 JLA.addReads(m1, m2);
91 }
92
93 /**
94 * Update module m to read all unnamed modules.
95 */
96 public static void addReadsAllUnnamed(Module m) {
97 JLA.addReadsAllUnnamed(m);
98 }
99
100 /**
101 * Updates module m1 to export a package to module m2.
102 * Same as m1.addExports(pn, m2) but without a caller check
103 */
104 public static void addExports(Module m1, String pn, Module m2) {
105 JLA.addExports(m1, pn, m2);
106 }
107
108 /**
109 * Updates module m to export a package to all unnamed modules.
110 */
111 public static void addExportsToAllUnnamed(Module m, String pn) {
112 JLA.addExportsToAllUnnamed(m, pn);
113 }
114
115 /**
116 * Updates module m1 to open a package to module m2.
117 * Same as m1.addOpens(pn, m2) but without a caller check.
118 */
119 public static void addOpens(Module m1, String pn, Module m2) {
120 JLA.addOpens(m1, pn, m2);
121 }
122
123 /**
124 * Updates module m to open a package to all unnamed modules.
125 */
126 public static void addOpensToAllUnnamed(Module m, String pn) {
127 JLA.addOpensToAllUnnamed(m, pn);
128 }
129
130 /**
131 * Updates module m to use a service.
132 * Same as m2.addUses(service) but without a caller check.
133 */
134 public static void addUses(Module m, Class<?> service) {
135 JLA.addUses(m, service);
136 }
137
138 /**
139 * Updates module m to provide a service
140 */
141 public static void addProvides(Module m, Class<?> service, Class<?> impl) {
142 ModuleLayer layer = m.getLayer();
143
144 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
145 ClassLoader loader = AccessController.doPrivileged(pa);
146
147 ClassLoader platformClassLoader = ClassLoaders.platformClassLoader();
148 if (layer == null || loader == null || loader == platformClassLoader) {
149 // update ClassLoader catalog
150 ServicesCatalog catalog;
151 if (loader == null) {
152 catalog = BootLoader.getServicesCatalog();
153 } else {
154 catalog = ServicesCatalog.getServicesCatalog(loader);
155 }
156 catalog.addProvider(m, service, impl);
157 }
158
159 if (layer != null) {
160 // update Layer catalog
161 JLA.getServicesCatalog(layer).addProvider(m, service, impl);
162 }
163 }
164
165 /**
166 * Resolves a collection of root modules, with service binding and the empty
167 * Configuration as the parent to create a Configuration for the boot layer.
168 *
169 * This method is intended to be used to create the Configuration for the
170 * boot layer during startup or at a link-time.
171 */
172 public static Configuration newBootLayerConfiguration(ModuleFinder finder,
173 Collection<String> roots,
174 PrintStream traceOutput)
175 {
176 return JLMA.resolveAndBind(finder, roots, traceOutput);
177 }
178
179 /**
180 * Called by the VM when code in the given Module has been transformed by
181 * an agent and so may have been instrumented to call into supporting
182 * classes on the boot class path or application class path.
183 */
184 public static void transformedByAgent(Module m) {
185 addReads(m, BootLoader.getUnnamedModule());
186 addReads(m, ClassLoaders.appClassLoader().getUnnamedModule());
187 }
188
189 /**
190 * Called by the VM to load a system module, typically "java.instrument" or
191 * "jdk.management.agent". If the module is not loaded then it is resolved
192 * and loaded (along with any dependences that weren't previously loaded)
193 * into a child layer.
194 */
195 public static synchronized Module loadModule(String name) {
196 ModuleLayer top = topLayer;
197 if (top == null)
198 top = ModuleLayer.boot();
199
200 Module module = top.findModule(name).orElse(null);
201 if (module != null) {
202 // module already loaded
203 return module;
204 }
205
206 // resolve the module with the top-most layer as the parent
207 ModuleFinder empty = ModuleFinder.of();
208 ModuleFinder finder = ModuleBootstrap.unlimitedFinder();
209 Set<String> roots = Set.of(name);
210 Configuration cf = top.configuration().resolveAndBind(empty, finder, roots);
211
212 // create the child layer
213 Function<String, ClassLoader> clf = ModuleLoaderMap.mappingFunction(cf);
214 ModuleLayer newLayer = top.defineModules(cf, clf);
215
216 // add qualified exports/opens to give access to modules in child layer
217 Map<String, Module> map = newLayer.modules().stream()
218 .collect(Collectors.toMap(Module::getName,
219 Function.identity()));
220 ModuleLayer layer = top;
221 while (layer != null) {
222 for (Module m : layer.modules()) {
223 // qualified exports
224 m.getDescriptor().exports().stream()
225 .filter(ModuleDescriptor.Exports::isQualified)
226 .forEach(e -> e.targets().forEach(target -> {
227 Module other = map.get(target);
228 if (other != null) {
229 addExports(m, e.source(), other);
230 }}));
231
232 // qualified opens
233 m.getDescriptor().opens().stream()
234 .filter(ModuleDescriptor.Opens::isQualified)
235 .forEach(o -> o.targets().forEach(target -> {
236 Module other = map.get(target);
237 if (other != null) {
238 addOpens(m, o.source(), other);
239 }}));
240 }
241
242 List<ModuleLayer> parents = layer.parents();
243 assert parents.size() <= 1;
244 layer = parents.isEmpty() ? null : parents.get(0);
245 }
246
247 // update security manager before making types visible
248 JLA.addNonExportedPackages(newLayer);
249
250 // update the built-in class loaders to make the types visible
251 for (ResolvedModule resolvedModule : cf.modules()) {
252 ModuleReference mref = resolvedModule.reference();
253 String mn = mref.descriptor().name();
254 ClassLoader cl = clf.apply(mn);
255 if (cl == null) {
256 BootLoader.loadModule(mref);
257 } else {
258 ((BuiltinClassLoader) cl).loadModule(mref);
259 }
260 }
261
262 // new top layer
263 topLayer = newLayer;
264
265 // return module
266 return newLayer.findModule(name)
267 .orElseThrow(() -> new InternalError("module not loaded"));
268
269 }
270
271 /**
272 * Finds the module with the given name in the boot layer or any child
273 * layers created to load the "java.instrument" or "jdk.management.agent"
274 * modules into a running VM.
275 */
276 public static Optional<Module> findLoadedModule(String name) {
277 ModuleLayer top = topLayer;
278 if (top == null)
279 top = ModuleLayer.boot();
280 return top.findModule(name);
281 }
282
283 // the top-most layer
284 private static volatile ModuleLayer topLayer;
285
286 }