1 /*
2 * Copyright (c) 1999, 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 java.lang.reflect;
27
28 import java.lang.module.ModuleDescriptor;
29 import java.security.AccessController;
30 import java.security.PrivilegedAction;
31 import java.util.Arrays;
32 import java.util.Collections;
33 import java.util.HashMap;
34 import java.util.HashSet;
35 import java.util.IdentityHashMap;
36 import java.util.List;
37 import java.util.Map;
38 import java.util.Objects;
39 import java.util.Set;
40 import java.util.concurrent.atomic.AtomicInteger;
41 import java.util.concurrent.atomic.AtomicLong;
42
43 import jdk.internal.access.JavaLangAccess;
44 import jdk.internal.access.SharedSecrets;
45 import jdk.internal.loader.BootLoader;
46 import jdk.internal.module.Modules;
47 import jdk.internal.misc.VM;
48 import jdk.internal.reflect.CallerSensitive;
49 import jdk.internal.reflect.Reflection;
50 import jdk.internal.loader.ClassLoaderValue;
51 import sun.reflect.misc.ReflectUtil;
52 import sun.security.action.GetBooleanAction;
53 import sun.security.action.GetPropertyAction;
54 import sun.security.util.SecurityConstants;
55
56 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC;
57
58
59 /**
60 *
61 * {@code Proxy} provides static methods for creating objects that act like instances
62 * of interfaces but allow for customized method invocation.
63 * To create a proxy instance for some interface {@code Foo}:
64 * <pre>{@code
65 * InvocationHandler handler = new MyInvocationHandler(...);
66 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
67 * new Class<?>[] { Foo.class },
68 * handler);
69 * }</pre>
70 *
71 * <p>
72 * A <em>proxy class</em> is a class created at runtime that implements a specified
73 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em>
74 * is an instance of a proxy class.
75 *
76 * Each proxy instance has an associated <i>invocation handler</i>
77 * object, which implements the interface {@link InvocationHandler}.
78 * A method invocation on a proxy instance through one of its proxy
79 * interfaces will be dispatched to the {@link InvocationHandler#invoke
80 * invoke} method of the instance's invocation handler, passing the proxy
81 * instance, a {@code java.lang.reflect.Method} object identifying
82 * the method that was invoked, and an array of type {@code Object}
83 * containing the arguments. The invocation handler processes the
84 * encoded method invocation as appropriate and the result that it
85 * returns will be returned as the result of the method invocation on
86 * the proxy instance.
87 *
88 * <p>A proxy class has the following properties:
89 *
90 * <ul>
91 * <li>The unqualified name of a proxy class is unspecified. The space
92 * of class names that begin with the string {@code "$Proxy"}
93 * should be, however, reserved for proxy classes.
94 *
95 * <li>The package and module in which a proxy class is defined is specified
96 * <a href="#membership">below</a>.
97 *
98 * <li>A proxy class is <em>final and non-abstract</em>.
99 *
100 * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
101 *
102 * <li>A proxy class implements exactly the interfaces specified at its
103 * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces}
104 * on its {@code Class} object will return an array containing the same
105 * list of interfaces (in the order specified at its creation), invoking
106 * {@link Class#getMethods getMethods} on its {@code Class} object will return
107 * an array of {@code Method} objects that include all of the
108 * methods in those interfaces, and invoking {@code getMethod} will
109 * find methods in the proxy interfaces as would be expected.
110 *
111 * <li>The {@link java.security.ProtectionDomain} of a proxy class
112 * is the same as that of system classes loaded by the bootstrap class
113 * loader, such as {@code java.lang.Object}, because the code for a
114 * proxy class is generated by trusted system code. This protection
115 * domain will typically be granted {@code java.security.AllPermission}.
116 *
117 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used
118 * to determine if a given class is a proxy class.
119 * </ul>
120 *
121 * <p>A proxy instance has the following properties:
122 *
123 * <ul>
124 * <li>Given a proxy instance {@code proxy} and one of the
125 * interfaces, {@code Foo}, implemented by its proxy class, the
126 * following expression will return true:
127 * <pre>
128 * {@code proxy instanceof Foo}
129 * </pre>
130 * and the following cast operation will succeed (rather than throwing
131 * a {@code ClassCastException}):
132 * <pre>
133 * {@code (Foo) proxy}
134 * </pre>
135 *
136 * <li>Each proxy instance has an associated invocation handler, the one
137 * that was passed to its constructor. The static
138 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
139 * will return the invocation handler associated with the proxy instance
140 * passed as its argument.
141 *
142 * <li>An interface method invocation on a proxy instance will be
143 * encoded and dispatched to the invocation handler's {@link
144 * InvocationHandler#invoke invoke} method as described in the
145 * documentation for that method.
146 *
147 * <li>An invocation of the {@code hashCode},
148 * {@code equals}, or {@code toString} methods declared in
149 * {@code java.lang.Object} on a proxy instance will be encoded and
150 * dispatched to the invocation handler's {@code invoke} method in
151 * the same manner as interface method invocations are encoded and
152 * dispatched, as described above. The declaring class of the
153 * {@code Method} object passed to {@code invoke} will be
154 * {@code java.lang.Object}. Other public methods of a proxy
155 * instance inherited from {@code java.lang.Object} are not
156 * overridden by a proxy class, so invocations of those methods behave
157 * like they do for instances of {@code java.lang.Object}.
158 * </ul>
159 *
160 * <h2><a id="membership">Package and Module Membership of Proxy Class</a></h2>
161 *
162 * The package and module to which a proxy class belongs are chosen such that
163 * the accessibility of the proxy class is in line with the accessibility of
164 * the proxy interfaces. Specifically, the package and the module membership
165 * of a proxy class defined via the
166 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or
167 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)}
168 * methods is specified as follows:
169 *
170 * <ol>
171 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em>
172 * packages:
173 * <ol type="a">
174 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
175 * <em>public</em> in a package exported by the
176 * {@linkplain ClassLoader#getUnnamedModule() unnamed module} of the specified
177 * loader. The name of the package is unspecified.</li>
178 *
179 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
180 * the proxy class is <em>non-public</em> in the package and module of the
181 * non-public interfaces. All the non-public interfaces must be in the same
182 * package and module; otherwise, proxying them is
183 * <a href="#restrictions">not possible</a>.</li>
184 * </ol>
185 * </li>
186 * <li>If at least one proxy interface is in a package that is
187 * <em>non-exported</em> and <em>non-open</em>:
188 * <ol type="a">
189 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
190 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of
191 * <a href="#dynamicmodule"><em>dynamic module</em>.</a>
192 * The names of the package and the module are unspecified.</li>
193 *
194 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
195 * the proxy class is <em>non-public</em> in the package and module of the
196 * non-public interfaces. All the non-public interfaces must be in the same
197 * package and module; otherwise, proxying them is
198 * <a href="#restrictions">not possible</a>.</li>
199 * </ol>
200 * </li>
201 * </ol>
202 *
203 * <p>
204 * Note that if proxy interfaces with a mix of accessibilities -- for example,
205 * an exported public interface and a non-exported non-public interface -- are
206 * proxied by the same instance, then the proxy class's accessibility is
207 * governed by the least accessible proxy interface.
208 * <p>
209 * Note that it is possible for arbitrary code to obtain access to a proxy class
210 * in an open package with {@link AccessibleObject#setAccessible setAccessible},
211 * whereas a proxy class in a non-open package is never accessible to
212 * code outside the module of the proxy class.
213 *
214 * <p>
215 * Throughout this specification, a "non-exported package" refers to a package
216 * that is not exported to all modules, and a "non-open package" refers to
217 * a package that is not open to all modules. Specifically, these terms refer to
218 * a package that either is not exported/open by its containing module or is
219 * exported/open in a qualified fashion by its containing module.
220 *
221 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3>
222 * <p>
223 * A dynamic module is a named module generated at runtime. A proxy class
224 * defined in a dynamic module is encapsulated and not accessible to any module.
225 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in
226 * a dynamic module will throw {@code IllegalAccessException};
227 * {@code Proxy.newProxyInstance} method should be used instead.
228 *
229 * <p>
230 * A dynamic module can read the modules of all of the superinterfaces of a proxy
231 * class and the modules of the types referenced by all public method signatures
232 * of a proxy class. If a superinterface or a referenced type, say {@code T},
233 * is in a non-exported package, the {@linkplain Module module} of {@code T} is
234 * updated to export the package of {@code T} to the dynamic module.
235 *
236 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
237 *
238 * <p>When two or more proxy interfaces contain a method with
239 * the same name and parameter signature, the order of the proxy class's
240 * interfaces becomes significant. When such a <i>duplicate method</i>
241 * is invoked on a proxy instance, the {@code Method} object passed
242 * to the invocation handler will not necessarily be the one whose
243 * declaring class is assignable from the reference type of the interface
244 * that the proxy's method was invoked through. This limitation exists
245 * because the corresponding method implementation in the generated proxy
246 * class cannot determine which interface it was invoked through.
247 * Therefore, when a duplicate method is invoked on a proxy instance,
248 * the {@code Method} object for the method in the foremost interface
249 * that contains the method (either directly or inherited through a
250 * superinterface) in the proxy class's list of interfaces is passed to
251 * the invocation handler's {@code invoke} method, regardless of the
252 * reference type through which the method invocation occurred.
253 *
254 * <p>If a proxy interface contains a method with the same name and
255 * parameter signature as the {@code hashCode}, {@code equals},
256 * or {@code toString} methods of {@code java.lang.Object},
257 * when such a method is invoked on a proxy instance, the
258 * {@code Method} object passed to the invocation handler will have
259 * {@code java.lang.Object} as its declaring class. In other words,
260 * the public, non-final methods of {@code java.lang.Object}
261 * logically precede all of the proxy interfaces for the determination of
262 * which {@code Method} object to pass to the invocation handler.
263 *
264 * <p>Note also that when a duplicate method is dispatched to an
265 * invocation handler, the {@code invoke} method may only throw
266 * checked exception types that are assignable to one of the exception
267 * types in the {@code throws} clause of the method in <i>all</i> of
268 * the proxy interfaces that it can be invoked through. If the
269 * {@code invoke} method throws a checked exception that is not
270 * assignable to any of the exception types declared by the method in one
271 * of the proxy interfaces that it can be invoked through, then an
272 * unchecked {@code UndeclaredThrowableException} will be thrown by
273 * the invocation on the proxy instance. This restriction means that not
274 * all of the exception types returned by invoking
275 * {@code getExceptionTypes} on the {@code Method} object
276 * passed to the {@code invoke} method can necessarily be thrown
277 * successfully by the {@code invoke} method.
278 *
279 * @author Peter Jones
280 * @see InvocationHandler
281 * @since 1.3
282 * @revised 9
283 * @spec JPMS
284 */
285 public class Proxy implements java.io.Serializable {
286 private static final long serialVersionUID = -2222568056686623797L;
287
288 /** parameter types of a proxy class constructor */
289 private static final Class<?>[] constructorParams =
290 { InvocationHandler.class };
291
292 /**
293 * a cache of proxy constructors with
294 * {@link Constructor#setAccessible(boolean) accessible} flag already set
295 */
296 private static final ClassLoaderValue<Constructor<?>> proxyCache =
297 new ClassLoaderValue<>();
298
299 /**
300 * System property to revert to generation of proxy class files for version 1.5 (V49).
301 * Set to "true" to generate v49 class file format.
302 */
303 private static final boolean PROXY_GENERATOR_V49 =
304 GetBooleanAction.privilegedGetProperty("jdk.proxy.ProxyGenerator.v49");
305
306 /**
307 * the invocation handler for this proxy instance.
308 * @serial
309 */
310 protected InvocationHandler h;
311
312 /**
313 * Prohibits instantiation.
314 */
315 private Proxy() {
316 }
317
318 /**
319 * Constructs a new {@code Proxy} instance from a subclass
320 * (typically, a dynamic proxy class) with the specified value
321 * for its invocation handler.
322 *
323 * @param h the invocation handler for this proxy instance
324 *
325 * @throws NullPointerException if the given invocation handler, {@code h},
326 * is {@code null}.
327 */
328 protected Proxy(InvocationHandler h) {
329 Objects.requireNonNull(h);
330 this.h = h;
331 }
332
333 /**
334 * Returns the {@code java.lang.Class} object for a proxy class
335 * given a class loader and an array of interfaces. The proxy class
336 * will be defined by the specified class loader and will implement
337 * all of the supplied interfaces. If any of the given interfaces
338 * is non-public, the proxy class will be non-public. If a proxy class
339 * for the same permutation of interfaces has already been defined by the
340 * class loader, then the existing proxy class will be returned; otherwise,
341 * a proxy class for those interfaces will be generated dynamically
342 * and defined by the class loader.
343 *
344 * @param loader the class loader to define the proxy class
345 * @param interfaces the list of interfaces for the proxy class
346 * to implement
347 * @return a proxy class that is defined in the specified class loader
348 * and that implements the specified interfaces
349 * @throws IllegalArgumentException if any of the <a href="#restrictions">
350 * restrictions</a> on the parameters are violated
351 * @throws SecurityException if a security manager, <em>s</em>, is present
352 * and any of the following conditions is met:
353 * <ul>
354 * <li> the given {@code loader} is {@code null} and
355 * the caller's class loader is not {@code null} and the
356 * invocation of {@link SecurityManager#checkPermission
357 * s.checkPermission} with
358 * {@code RuntimePermission("getClassLoader")} permission
359 * denies access.</li>
360 * <li> for each proxy interface, {@code intf},
361 * the caller's class loader is not the same as or an
362 * ancestor of the class loader for {@code intf} and
363 * invocation of {@link SecurityManager#checkPackageAccess
364 * s.checkPackageAccess()} denies access to {@code intf}.</li>
365 * </ul>
366 * @throws NullPointerException if the {@code interfaces} array
367 * argument or any of its elements are {@code null}
368 *
369 * @deprecated Proxy classes generated in a named module are encapsulated
370 * and not accessible to code outside its module.
371 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
372 * will throw {@code IllegalAccessException} when it is called on
373 * an inaccessible proxy class.
374 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
375 * to create a proxy instance instead.
376 *
377 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
378 * @revised 9
379 * @spec JPMS
380 */
381 @Deprecated
382 @CallerSensitive
383 public static Class<?> getProxyClass(ClassLoader loader,
384 Class<?>... interfaces)
385 throws IllegalArgumentException
386 {
387 Class<?> caller = System.getSecurityManager() == null
388 ? null
389 : Reflection.getCallerClass();
390
391 return getProxyConstructor(caller, loader, interfaces)
392 .getDeclaringClass();
393 }
394
395 /**
396 * Returns the {@code Constructor} object of a proxy class that takes a
397 * single argument of type {@link InvocationHandler}, given a class loader
398 * and an array of interfaces. The returned constructor will have the
399 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
400 *
401 * @param caller passed from a public-facing @CallerSensitive method if
402 * SecurityManager is set or {@code null} if there's no
403 * SecurityManager
404 * @param loader the class loader to define the proxy class
405 * @param interfaces the list of interfaces for the proxy class
406 * to implement
407 * @return a Constructor of the proxy class taking single
408 * {@code InvocationHandler} parameter
409 */
410 private static Constructor<?> getProxyConstructor(Class<?> caller,
411 ClassLoader loader,
412 Class<?>... interfaces)
413 {
414 // optimization for single interface
415 if (interfaces.length == 1) {
416 Class<?> intf = interfaces[0];
417 if (caller != null) {
418 checkProxyAccess(caller, loader, intf);
419 }
420 return proxyCache.sub(intf).computeIfAbsent(
421 loader,
422 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
423 );
424 } else {
425 // interfaces cloned
426 final Class<?>[] intfsArray = interfaces.clone();
427 if (caller != null) {
428 checkProxyAccess(caller, loader, intfsArray);
429 }
430 final List<Class<?>> intfs = Arrays.asList(intfsArray);
431 return proxyCache.sub(intfs).computeIfAbsent(
432 loader,
433 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
434 );
435 }
436 }
437
438 /*
439 * Check permissions required to create a Proxy class.
440 *
441 * To define a proxy class, it performs the access checks as in
442 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
443 * 1. "getClassLoader" permission check if loader == null
444 * 2. checkPackageAccess on the interfaces it implements
445 *
446 * To get a constructor and new instance of a proxy class, it performs
447 * the package access check on the interfaces it implements
448 * as in Class.getConstructor.
449 *
450 * If an interface is non-public, the proxy class must be defined by
451 * the defining loader of the interface. If the caller's class loader
452 * is not the same as the defining loader of the interface, the VM
453 * will throw IllegalAccessError when the generated proxy class is
454 * being defined.
455 */
456 private static void checkProxyAccess(Class<?> caller,
457 ClassLoader loader,
458 Class<?> ... interfaces)
459 {
460 SecurityManager sm = System.getSecurityManager();
461 if (sm != null) {
462 ClassLoader ccl = caller.getClassLoader();
463 if (loader == null && ccl != null) {
464 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
465 }
466 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
467 }
468 }
469
470 /**
471 * Builder for a proxy class.
472 *
473 * If the module is not specified in this ProxyBuilder constructor,
474 * it will map from the given loader and interfaces to the module
475 * in which the proxy class will be defined.
476 */
477 private static final class ProxyBuilder {
478 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
479
480 // prefix for all proxy class names
481 private static final String proxyClassNamePrefix = "$Proxy";
482
483 // next number to use for generation of unique proxy class names
484 private static final AtomicLong nextUniqueNumber = new AtomicLong();
485
486 // a reverse cache of defined proxy classes
487 private static final ClassLoaderValue<Boolean> reverseProxyCache =
488 new ClassLoaderValue<>();
489
490 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) {
491 String proxyPkg = null; // package to define proxy class in
492 int accessFlags = Modifier.PUBLIC | Modifier.FINAL;
493
494 /*
495 * Record the package of a non-public proxy interface so that the
496 * proxy class will be defined in the same package. Verify that
497 * all non-public proxy interfaces are in the same package.
498 */
499 for (Class<?> intf : interfaces) {
500 int flags = intf.getModifiers();
501 if (!Modifier.isPublic(flags)) {
502 accessFlags = Modifier.FINAL; // non-public, final
503 String pkg = intf.getPackageName();
504 if (proxyPkg == null) {
505 proxyPkg = pkg;
506 } else if (!pkg.equals(proxyPkg)) {
507 throw new IllegalArgumentException(
508 "non-public interfaces from different packages");
509 }
510 }
511 }
512
513 if (proxyPkg == null) {
514 // all proxy interfaces are public
515 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName()
516 : PROXY_PACKAGE_PREFIX;
517 } else if (proxyPkg.isEmpty() && m.isNamed()) {
518 throw new IllegalArgumentException(
519 "Unnamed package cannot be added to " + m);
520 }
521
522 if (m.isNamed()) {
523 if (!m.getDescriptor().packages().contains(proxyPkg)) {
524 throw new InternalError(proxyPkg + " not exist in " + m.getName());
525 }
526 }
527
528 /*
529 * Choose a name for the proxy class to generate.
530 */
531 long num = nextUniqueNumber.getAndIncrement();
532 String proxyName = proxyPkg.isEmpty()
533 ? proxyClassNamePrefix + num
534 : proxyPkg + "." + proxyClassNamePrefix + num;
535
536 ClassLoader loader = getLoader(m);
537 trace(proxyName, m, loader, interfaces);
538
539 /*
540 * Generate the specified proxy class.
541 */
542 byte[] proxyClassFile = PROXY_GENERATOR_V49
543 ? ProxyGenerator_v49.generateProxyClass(proxyName, interfaces, accessFlags)
544 : ProxyGenerator.generateProxyClass(loader, proxyName, interfaces, accessFlags);
545 try {
546 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
547 null, "__dynamic_proxy__");
548 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
549 return pc;
550 } catch (ClassFormatError e) {
551 /*
552 * A ClassFormatError here means that (barring bugs in the
553 * proxy class generation code) there was some other
554 * invalid aspect of the arguments supplied to the proxy
555 * class creation (such as virtual machine limitations
556 * exceeded).
557 */
558 throw new IllegalArgumentException(e.toString());
559 }
560 }
561
562 /**
563 * Test if given class is a class defined by
564 * {@link #defineProxyClass(Module, List)}
565 */
566 static boolean isProxyClass(Class<?> c) {
567 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
568 Boolean.TRUE);
569 }
570
571 private static boolean isExportedType(Class<?> c) {
572 String pn = c.getPackageName();
573 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
574 }
575
576 private static boolean isPackagePrivateType(Class<?> c) {
577 return !Modifier.isPublic(c.getModifiers());
578 }
579
580 private static String toDetails(Class<?> c) {
581 String access = "unknown";
582 if (isExportedType(c)) {
583 access = "exported";
584 } else if (isPackagePrivateType(c)) {
585 access = "package-private";
586 } else {
587 access = "module-private";
588 }
589 ClassLoader ld = c.getClassLoader();
590 return String.format(" %s/%s %s loader %s",
591 c.getModule().getName(), c.getName(), access, ld);
592 }
593
594 static void trace(String cn,
595 Module module,
596 ClassLoader loader,
597 List<Class<?>> interfaces) {
598 if (isDebug()) {
599 System.err.format("PROXY: %s/%s defined by %s%n",
600 module.getName(), cn, loader);
601 }
602 if (isDebug("debug")) {
603 interfaces.forEach(c -> System.out.println(toDetails(c)));
604 }
605 }
606
607 private static final String DEBUG =
608 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
609
610 private static boolean isDebug() {
611 return !DEBUG.isEmpty();
612 }
613 private static boolean isDebug(String flag) {
614 return DEBUG.equals(flag);
615 }
616
617 // ProxyBuilder instance members start here....
618
619 private final List<Class<?>> interfaces;
620 private final Module module;
621 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
622 if (!VM.isModuleSystemInited()) {
623 throw new InternalError("Proxy is not supported until "
624 + "module system is fully initialized");
625 }
626 if (interfaces.size() > 65535) {
627 throw new IllegalArgumentException("interface limit exceeded: "
628 + interfaces.size());
629 }
630
631 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
632
633 // IAE if violates any restrictions specified in newProxyInstance
634 validateProxyInterfaces(loader, interfaces, refTypes);
635
636 this.interfaces = interfaces;
637 this.module = mapToModule(loader, interfaces, refTypes);
638 assert getLoader(module) == loader;
639 }
640
641 ProxyBuilder(ClassLoader loader, Class<?> intf) {
642 this(loader, Collections.singletonList(intf));
643 }
644
645 /**
646 * Generate a proxy class and return its proxy Constructor with
647 * accessible flag already set. If the target module does not have access
648 * to any interface types, IllegalAccessError will be thrown by the VM
649 * at defineClass time.
650 *
651 * Must call the checkProxyAccess method to perform permission checks
652 * before calling this.
653 */
654 Constructor<?> build() {
655 Class<?> proxyClass = defineProxyClass(module, interfaces);
656 final Constructor<?> cons;
657 try {
658 cons = proxyClass.getConstructor(constructorParams);
659 } catch (NoSuchMethodException e) {
660 throw new InternalError(e.toString(), e);
661 }
662 AccessController.doPrivileged(new PrivilegedAction<Void>() {
663 public Void run() {
664 cons.setAccessible(true);
665 return null;
666 }
667 });
668 return cons;
669 }
670
671 /**
672 * Validate the given proxy interfaces and the given referenced types
673 * are visible to the defining loader.
674 *
675 * @throws IllegalArgumentException if it violates the restrictions
676 * specified in {@link Proxy#newProxyInstance}
677 */
678 private static void validateProxyInterfaces(ClassLoader loader,
679 List<Class<?>> interfaces,
680 Set<Class<?>> refTypes)
681 {
682 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
683 for (Class<?> intf : interfaces) {
684 /*
685 * Verify that the class loader resolves the name of this
686 * interface to the same Class object.
687 */
688 ensureVisible(loader, intf);
689
690 /*
691 * Verify that the Class object actually represents an
692 * interface.
693 */
694 if (!intf.isInterface()) {
695 throw new IllegalArgumentException(intf.getName() + " is not an interface");
696 }
697
698 /*
699 * Verify that this interface is not a duplicate.
700 */
701 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
702 throw new IllegalArgumentException("repeated interface: " + intf.getName());
703 }
704 }
705
706 for (Class<?> type : refTypes) {
707 ensureVisible(loader, type);
708 }
709 }
710
711 /*
712 * Returns all types referenced by all public non-static method signatures of
713 * the proxy interfaces
714 */
715 private static Set<Class<?>> referencedTypes(ClassLoader loader,
716 List<Class<?>> interfaces) {
717 var types = new HashSet<Class<?>>();
718 for (var intf : interfaces) {
719 for (Method m : intf.getMethods()) {
720 if (!Modifier.isStatic(m.getModifiers())) {
721 addElementType(types, m.getReturnType());
722 addElementTypes(types, m.getSharedParameterTypes());
723 addElementTypes(types, m.getSharedExceptionTypes());
724 }
725 }
726 }
727 return types;
728 }
729
730 private static void addElementTypes(HashSet<Class<?>> types,
731 Class<?> ... classes) {
732 for (var cls : classes) {
733 addElementType(types, cls);
734 }
735 }
736
737 private static void addElementType(HashSet<Class<?>> types,
738 Class<?> cls) {
739 var type = getElementType(cls);
740 if (!type.isPrimitive()) {
741 types.add(type);
742 }
743 }
744
745 /**
746 * Returns the module that the generated proxy class belongs to.
747 *
748 * If all proxy interfaces are public and in exported packages,
749 * then the proxy class is in unnamed module.
750 *
751 * If any of proxy interface is package-private, then the proxy class
752 * is in the same module of the package-private interface.
753 *
754 * If all proxy interfaces are public and at least one in a non-exported
755 * package, then the proxy class is in a dynamic module in a
756 * non-exported package. Reads edge and qualified exports are added
757 * for dynamic module to access.
758 */
759 private static Module mapToModule(ClassLoader loader,
760 List<Class<?>> interfaces,
761 Set<Class<?>> refTypes) {
762 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>();
763 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
764 for (Class<?> intf : interfaces) {
765 Module m = intf.getModule();
766 if (Modifier.isPublic(intf.getModifiers())) {
767 // module-private types
768 if (!m.isExported(intf.getPackageName())) {
769 modulePrivateTypes.put(intf, m);
770 }
771 } else {
772 packagePrivateTypes.put(intf, m);
773 }
774 }
775
776 // all proxy interfaces are public and exported, the proxy class
777 // is in unnamed module. Such proxy class is accessible to
778 // any unnamed module and named module that can read unnamed module
779 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) {
780 return loader != null ? loader.getUnnamedModule()
781 : BootLoader.getUnnamedModule();
782 }
783
784 if (packagePrivateTypes.size() > 0) {
785 // all package-private types must be in the same runtime package
786 // i.e. same package name and same module (named or unnamed)
787 //
788 // Configuration will fail if M1 and in M2 defined by the same loader
789 // and both have the same package p (so no need to check class loader)
790 if (packagePrivateTypes.size() > 1 &&
791 (packagePrivateTypes.keySet().stream() // more than one package
792 .map(Class::getPackageName).distinct().count() > 1 ||
793 packagePrivateTypes.values().stream() // or more than one module
794 .distinct().count() > 1)) {
795 throw new IllegalArgumentException(
796 "non-public interfaces from different packages");
797 }
798
799 // all package-private types are in the same module (named or unnamed)
800 Module target = null;
801 for (Module m : packagePrivateTypes.values()) {
802 if (getLoader(m) != loader) {
803 // the specified loader is not the same class loader
804 // of the non-public interface
805 throw new IllegalArgumentException(
806 "non-public interface is not defined by the given loader");
807 }
808 target = m;
809 }
810
811 // validate if the target module can access all other interfaces
812 for (Class<?> intf : interfaces) {
813 Module m = intf.getModule();
814 if (m == target) continue;
815
816 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) {
817 throw new IllegalArgumentException(target + " can't access " + intf.getName());
818 }
819 }
820
821 // return the module of the package-private interface
822 return target;
823 }
824
825 // All proxy interfaces are public and at least one in a non-exported
826 // package. So maps to a dynamic proxy module and add reads edge
827 // and qualified exports, if necessary
828 Module target = getDynamicModule(loader);
829
830 // set up proxy class access to proxy interfaces and types
831 // referenced in the method signature
832 Set<Class<?>> types = new HashSet<>(interfaces);
833 types.addAll(refTypes);
834 for (Class<?> c : types) {
835 ensureAccess(target, c);
836 }
837 return target;
838 }
839
840 /*
841 * Ensure the given module can access the given class.
842 */
843 private static void ensureAccess(Module target, Class<?> c) {
844 Module m = c.getModule();
845 // add read edge and qualified export for the target module to access
846 if (!target.canRead(m)) {
847 Modules.addReads(target, m);
848 }
849 String pn = c.getPackageName();
850 if (!m.isExported(pn, target)) {
851 Modules.addExports(m, pn, target);
852 }
853 }
854
855 /*
856 * Ensure the given class is visible to the class loader.
857 */
858 private static void ensureVisible(ClassLoader ld, Class<?> c) {
859 Class<?> type = null;
860 try {
861 type = Class.forName(c.getName(), false, ld);
862 } catch (ClassNotFoundException e) {
863 }
864 if (type != c) {
865 throw new IllegalArgumentException(c.getName() +
866 " referenced from a method is not visible from class loader");
867 }
868 }
869
870 private static Class<?> getElementType(Class<?> type) {
871 Class<?> e = type;
872 while (e.isArray()) {
873 e = e.getComponentType();
874 }
875 return e;
876 }
877
878 private static final ClassLoaderValue<Module> dynProxyModules =
879 new ClassLoaderValue<>();
880 private static final AtomicInteger counter = new AtomicInteger();
881
882 /*
883 * Define a dynamic module for the generated proxy classes in
884 * a non-exported package named com.sun.proxy.$MODULE.
885 *
886 * Each class loader will have one dynamic module.
887 */
888 private static Module getDynamicModule(ClassLoader loader) {
889 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
890 // create a dynamic module and setup module access
891 String mn = "jdk.proxy" + counter.incrementAndGet();
892 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
893 ModuleDescriptor descriptor =
894 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC))
895 .packages(Set.of(pn))
896 .build();
897 Module m = Modules.defineModule(ld, descriptor, null);
898 Modules.addReads(m, Proxy.class.getModule());
899 // java.base to create proxy instance
900 Modules.addExports(m, pn, Object.class.getModule());
901 return m;
902 });
903 }
904 }
905
906 /**
907 * Returns a proxy instance for the specified interfaces
908 * that dispatches method invocations to the specified invocation
909 * handler.
910 * <p>
911 * <a id="restrictions">{@code IllegalArgumentException} will be thrown
912 * if any of the following restrictions is violated:</a>
913 * <ul>
914 * <li>All of {@code Class} objects in the given {@code interfaces} array
915 * must represent interfaces, not classes or primitive types.
916 *
917 * <li>No two elements in the {@code interfaces} array may
918 * refer to identical {@code Class} objects.
919 *
920 * <li>All of the interface types must be visible by name through the
921 * specified class loader. In other words, for class loader
922 * {@code cl} and every interface {@code i}, the following
923 * expression must be true:<p>
924 * {@code Class.forName(i.getName(), false, cl) == i}
925 *
926 * <li>All of the types referenced by all
927 * public method signatures of the specified interfaces
928 * and those inherited by their superinterfaces
929 * must be visible by name through the specified class loader.
930 *
931 * <li>All non-public interfaces must be in the same package
932 * and module, defined by the specified class loader and
933 * the module of the non-public interfaces can access all of
934 * the interface types; otherwise, it would not be possible for
935 * the proxy class to implement all of the interfaces,
936 * regardless of what package it is defined in.
937 *
938 * <li>For any set of member methods of the specified interfaces
939 * that have the same signature:
940 * <ul>
941 * <li>If the return type of any of the methods is a primitive
942 * type or void, then all of the methods must have that same
943 * return type.
944 * <li>Otherwise, one of the methods must have a return type that
945 * is assignable to all of the return types of the rest of the
946 * methods.
947 * </ul>
948 *
949 * <li>The resulting proxy class must not exceed any limits imposed
950 * on classes by the virtual machine. For example, the VM may limit
951 * the number of interfaces that a class may implement to 65535; in
952 * that case, the size of the {@code interfaces} array must not
953 * exceed 65535.
954 * </ul>
955 *
956 * <p>Note that the order of the specified proxy interfaces is
957 * significant: two requests for a proxy class with the same combination
958 * of interfaces but in a different order will result in two distinct
959 * proxy classes.
960 *
961 * @param loader the class loader to define the proxy class
962 * @param interfaces the list of interfaces for the proxy class
963 * to implement
964 * @param h the invocation handler to dispatch method invocations to
965 * @return a proxy instance with the specified invocation handler of a
966 * proxy class that is defined by the specified class loader
967 * and that implements the specified interfaces
968 * @throws IllegalArgumentException if any of the <a href="#restrictions">
969 * restrictions</a> on the parameters are violated
970 * @throws SecurityException if a security manager, <em>s</em>, is present
971 * and any of the following conditions is met:
972 * <ul>
973 * <li> the given {@code loader} is {@code null} and
974 * the caller's class loader is not {@code null} and the
975 * invocation of {@link SecurityManager#checkPermission
976 * s.checkPermission} with
977 * {@code RuntimePermission("getClassLoader")} permission
978 * denies access;</li>
979 * <li> for each proxy interface, {@code intf},
980 * the caller's class loader is not the same as or an
981 * ancestor of the class loader for {@code intf} and
982 * invocation of {@link SecurityManager#checkPackageAccess
983 * s.checkPackageAccess()} denies access to {@code intf};</li>
984 * <li> any of the given proxy interfaces is non-public and the
985 * caller class is not in the same {@linkplain Package runtime package}
986 * as the non-public interface and the invocation of
987 * {@link SecurityManager#checkPermission s.checkPermission} with
988 * {@code ReflectPermission("newProxyInPackage.{package name}")}
989 * permission denies access.</li>
990 * </ul>
991 * @throws NullPointerException if the {@code interfaces} array
992 * argument or any of its elements are {@code null}, or
993 * if the invocation handler, {@code h}, is
994 * {@code null}
995 *
996 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
997 * @revised 9
998 * @spec JPMS
999 */
1000 @CallerSensitive
1001 public static Object newProxyInstance(ClassLoader loader,
1002 Class<?>[] interfaces,
1003 InvocationHandler h) {
1004 Objects.requireNonNull(h);
1005
1006 final Class<?> caller = System.getSecurityManager() == null
1007 ? null
1008 : Reflection.getCallerClass();
1009
1010 /*
1011 * Look up or generate the designated proxy class and its constructor.
1012 */
1013 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
1014
1015 return newProxyInstance(caller, cons, h);
1016 }
1017
1018 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
1019 Constructor<?> cons,
1020 InvocationHandler h) {
1021 /*
1022 * Invoke its constructor with the designated invocation handler.
1023 */
1024 try {
1025 if (caller != null) {
1026 checkNewProxyPermission(caller, cons.getDeclaringClass());
1027 }
1028
1029 return cons.newInstance(new Object[]{h});
1030 } catch (IllegalAccessException | InstantiationException e) {
1031 throw new InternalError(e.toString(), e);
1032 } catch (InvocationTargetException e) {
1033 Throwable t = e.getCause();
1034 if (t instanceof RuntimeException) {
1035 throw (RuntimeException) t;
1036 } else {
1037 throw new InternalError(t.toString(), t);
1038 }
1039 }
1040 }
1041
1042 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1043 SecurityManager sm = System.getSecurityManager();
1044 if (sm != null) {
1045 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1046 ClassLoader ccl = caller.getClassLoader();
1047 ClassLoader pcl = proxyClass.getClassLoader();
1048
1049 // do permission check if the caller is in a different runtime package
1050 // of the proxy class
1051 String pkg = proxyClass.getPackageName();
1052 String callerPkg = caller.getPackageName();
1053
1054 if (pcl != ccl || !pkg.equals(callerPkg)) {
1055 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1056 }
1057 }
1058 }
1059 }
1060
1061 /**
1062 * Returns the class loader for the given module.
1063 */
1064 private static ClassLoader getLoader(Module m) {
1065 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1066 return AccessController.doPrivileged(pa);
1067 }
1068
1069 /**
1070 * Returns true if the given class is a proxy class.
1071 *
1072 * @implNote The reliability of this method is important for the ability
1073 * to use it to make security decisions, so its implementation should
1074 * not just test if the class in question extends {@code Proxy}.
1075 *
1076 * @param cl the class to test
1077 * @return {@code true} if the class is a proxy class and
1078 * {@code false} otherwise
1079 * @throws NullPointerException if {@code cl} is {@code null}
1080 *
1081 * @revised 9
1082 * @spec JPMS
1083 */
1084 public static boolean isProxyClass(Class<?> cl) {
1085 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1086 }
1087
1088 /**
1089 * Returns the invocation handler for the specified proxy instance.
1090 *
1091 * @param proxy the proxy instance to return the invocation handler for
1092 * @return the invocation handler for the proxy instance
1093 * @throws IllegalArgumentException if the argument is not a
1094 * proxy instance
1095 * @throws SecurityException if a security manager, <em>s</em>, is present
1096 * and the caller's class loader is not the same as or an
1097 * ancestor of the class loader for the invocation handler
1098 * and invocation of {@link SecurityManager#checkPackageAccess
1099 * s.checkPackageAccess()} denies access to the invocation
1100 * handler's class.
1101 */
1102 @CallerSensitive
1103 public static InvocationHandler getInvocationHandler(Object proxy)
1104 throws IllegalArgumentException
1105 {
1106 /*
1107 * Verify that the object is actually a proxy instance.
1108 */
1109 if (!isProxyClass(proxy.getClass())) {
1110 throw new IllegalArgumentException("not a proxy instance");
1111 }
1112
1113 final Proxy p = (Proxy) proxy;
1114 final InvocationHandler ih = p.h;
1115 if (System.getSecurityManager() != null) {
1116 Class<?> ihClass = ih.getClass();
1117 Class<?> caller = Reflection.getCallerClass();
1118 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1119 ihClass.getClassLoader()))
1120 {
1121 ReflectUtil.checkPackageAccess(ihClass);
1122 }
1123 }
1124
1125 return ih;
1126 }
1127
1128 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1129 }