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