1 /*
2 * Copyright (c) 1999, 2013, 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.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.util.Arrays;
31 import java.util.Collections;
32 import java.util.Deque;
33 import java.util.HashMap;
34 import java.util.HashSet;
35 import java.util.IdentityHashMap;
36 import java.util.LinkedList;
37 import java.util.List;
38 import java.util.Map;
39 import java.util.Objects;
40 import java.util.Set;
41 import java.util.concurrent.atomic.AtomicInteger;
42 import java.util.concurrent.atomic.AtomicLong;
43 import java.util.stream.Collectors;
44 import java.util.stream.Stream;
45
46 import jdk.internal.loader.BootLoader;
47 import jdk.internal.module.Modules;
48 import jdk.internal.misc.Unsafe;
49 import jdk.internal.misc.VM;
50 import sun.reflect.CallerSensitive;
51 import sun.reflect.Reflection;
52 import sun.reflect.misc.ReflectUtil;
53 import sun.security.util.SecurityConstants;
54
55 /**
56 *
57 * {@code Proxy} provides static methods for creating objects that act like instances
58 * of interfaces but allow for customized method invocation.
59 * To create a proxy instance for some interface {@code Foo}:
60 * <pre>{@code
61 * InvocationHandler handler = new MyInvocationHandler(...);
62 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
63 * new Class<?>[] { Foo.class },
64 * handler);
65 * }</pre>
66 *
67 * <p>
68 * A <em>proxy class</em> is a class created at runtime that implements a specified
69 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em>
70 * is an instance of a proxy class.
71 *
72 * Each proxy instance has an associated <i>invocation handler</i>
73 * object, which implements the interface {@link InvocationHandler}.
74 * A method invocation on a proxy instance through one of its proxy
75 * interfaces will be dispatched to the {@link InvocationHandler#invoke
76 * invoke} method of the instance's invocation handler, passing the proxy
77 * instance, a {@code java.lang.reflect.Method} object identifying
78 * the method that was invoked, and an array of type {@code Object}
79 * containing the arguments. The invocation handler processes the
80 * encoded method invocation as appropriate and the result that it
81 * returns will be returned as the result of the method invocation on
82 * the proxy instance.
83 *
84 * <p>A proxy class has the following properties:
85 *
86 * <ul>
87 * <li>The unqualified name of a proxy class is unspecified. The space
88 * of class names that begin with the string {@code "$Proxy"}
89 * should be, however, reserved for proxy classes.
90 *
91 * <li>The package and module in which a proxy class is defined is specified
92 * <a href="#membership">below</a>.
93 *
94 * <li>A proxy class is <em>final and non-abstract</em>.
95 *
96 * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
97 *
98 * <li>A proxy class implements exactly the interfaces specified at its
99 * creation, in the same order. Invoking {@link Class#getInterfaces getInterfaces}
100 * on its {@code Class} object will return an array containing the same
101 * list of interfaces (in the order specified at its creation), invoking
102 * {@link Class#getMethods getMethods} on its {@code Class} object will return
103 * an array of {@code Method} objects that include all of the
104 * methods in those interfaces, and invoking {@code getMethod} will
105 * find methods in the proxy interfaces as would be expected.
106 *
107 * <li>The {@link java.security.ProtectionDomain} of a proxy class
108 * is the same as that of system classes loaded by the bootstrap class
109 * loader, such as {@code java.lang.Object}, because the code for a
110 * proxy class is generated by trusted system code. This protection
111 * domain will typically be granted {@code java.security.AllPermission}.
112 *
113 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used
114 * to determine if a given class is a proxy class.
115 * </ul>
116 *
117 * <p>A proxy instance has the following properties:
118 *
119 * <ul>
120 * <li>Given a proxy instance {@code proxy} and one of the
121 * interfaces, {@code Foo}, implemented by its proxy class, the
122 * following expression will return true:
123 * <pre>
124 * {@code proxy instanceof Foo}
125 * </pre>
126 * and the following cast operation will succeed (rather than throwing
127 * a {@code ClassCastException}):
128 * <pre>
129 * {@code (Foo) proxy}
130 * </pre>
131 *
132 * <li>Each proxy instance has an associated invocation handler, the one
133 * that was passed to its constructor. The static
134 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
135 * will return the invocation handler associated with the proxy instance
136 * passed as its argument.
137 *
138 * <li>An interface method invocation on a proxy instance will be
139 * encoded and dispatched to the invocation handler's {@link
140 * InvocationHandler#invoke invoke} method as described in the
141 * documentation for that method.
142 *
143 * <li>An invocation of the {@code hashCode},
144 * {@code equals}, or {@code toString} methods declared in
145 * {@code java.lang.Object} on a proxy instance will be encoded and
146 * dispatched to the invocation handler's {@code invoke} method in
147 * the same manner as interface method invocations are encoded and
148 * dispatched, as described above. The declaring class of the
149 * {@code Method} object passed to {@code invoke} will be
150 * {@code java.lang.Object}. Other public methods of a proxy
151 * instance inherited from {@code java.lang.Object} are not
152 * overridden by a proxy class, so invocations of those methods behave
153 * like they do for instances of {@code java.lang.Object}.
154 * </ul>
155 *
156 * <h3><a name="membership">Package and Module Membership of Proxy Class</a></h3>
157 *
158 * The package and module to which a proxy class belongs are chosen such that
159 * the accessibility of the proxy class is in line with the accessibility of
160 * the proxy interfaces. Specifically, the package and the module membership
161 * of a proxy class defined via the
162 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or
163 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)}
164 * methods is specified as follows:
165 *
166 * <ol>
167 * <li>If all the proxy interfaces are in <em>exported</em> packages:
168 * <ol type="a">
169 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
170 * <em>public</em> in a package exported by the
171 * {@linkplain ClassLoader#getUnnamedModule() unnamed module} of the specified
172 * loader. The name of the package is unspecified.</li>
173 *
174 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
175 * the proxy class is <em>non-public</em> in the package and module of the
176 * non-public interfaces. All the non-public interfaces must be in the same
177 * package and module; otherwise, proxying them is
178 * <a href="#restrictions">not possible</a>.</li>
179 * </ol>
180 * </li>
181 * <li>If at least one proxy interface is a <em>non-exported</em> package:
182 * <ol type="a">
183 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
184 * <em>public</em> in a <em>non-exported</em> package of
185 * <a href="#dynamicmodule"><em>dynamic module</em>.</a>
186 * The names of the package and the module are unspecified.</li>
187 *
188 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
189 * the proxy class is <em>non-public</em> in the package and module of the
190 * non-public interfaces. All the non-public interfaces must be in the same
191 * package and module; otherwise, proxying them is
192 * <a href="#restrictions">not possible</a>.</li>
193 * </ol>
194 * </li>
195 * </ol>
196 *
197 * <p>
198 * Note that if proxy interfaces with a mix of accessibilities --
199 * exported public, exported non-public, non-exported public, non-exported non-public --
200 * are proxied by the same instance, then the proxy class's accessibility is
201 * governed by the least accessible proxy interface.
202 * <p>
203 * Note that it is possible for arbitrary code to obtain access to a proxy class
204 * in an exported package with {@link AccessibleObject#setAccessible setAccessible},
205 * whereas a proxy class in a non-exported package is never accessible to
206 * code outside the module of the proxy class.
207 *
208 * <p>
209 * Throughout this specification, a "non-exported package" refers to a package that
210 * is not exported to all modules. Specifically, it refers to a package that
211 * either is not exported at all by its containing module or is exported in a
212 * qualified fashion by its containing module.
213 *
214 * <h3><a name="dynamicmodule">Dynamic Modules</a></h3>
215 * <p>
216 * A dynamic module is a named module generated at runtime. A proxy class
217 * defined in a dynamic module is encapsulated and not accessible to any module.
218 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in
219 * a dynamic module will throw {@code IllegalAccessException};
220 * {@code Proxy.newProxyInstance} method should be used instead.
221 *
222 * <p>
223 * A dynamic module can read the modules of all of the superinterfaces of a proxy class
224 * and the modules of the types referenced by all public method signatures
225 * of a proxy class. If a superinterface or a referenced type, say {@code T},
226 * is in a non-exported package, the {@linkplain java.lang.reflect.Module module}
227 * of {@code T} is updated to export the package of {@code T} to the dynamic module.
228 *
229 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
230 *
231 * <p>When two or more proxy interfaces contain a method with
232 * the same name and parameter signature, the order of the proxy class's
233 * interfaces becomes significant. When such a <i>duplicate method</i>
234 * is invoked on a proxy instance, the {@code Method} object passed
235 * to the invocation handler will not necessarily be the one whose
236 * declaring class is assignable from the reference type of the interface
237 * that the proxy's method was invoked through. This limitation exists
238 * because the corresponding method implementation in the generated proxy
239 * class cannot determine which interface it was invoked through.
240 * Therefore, when a duplicate method is invoked on a proxy instance,
241 * the {@code Method} object for the method in the foremost interface
242 * that contains the method (either directly or inherited through a
243 * superinterface) in the proxy class's list of interfaces is passed to
244 * the invocation handler's {@code invoke} method, regardless of the
245 * reference type through which the method invocation occurred.
246 *
247 * <p>If a proxy interface contains a method with the same name and
248 * parameter signature as the {@code hashCode}, {@code equals},
249 * or {@code toString} methods of {@code java.lang.Object},
250 * when such a method is invoked on a proxy instance, the
251 * {@code Method} object passed to the invocation handler will have
252 * {@code java.lang.Object} as its declaring class. In other words,
253 * the public, non-final methods of {@code java.lang.Object}
254 * logically precede all of the proxy interfaces for the determination of
255 * which {@code Method} object to pass to the invocation handler.
256 *
257 * <p>Note also that when a duplicate method is dispatched to an
258 * invocation handler, the {@code invoke} method may only throw
259 * checked exception types that are assignable to one of the exception
260 * types in the {@code throws} clause of the method in <i>all</i> of
261 * the proxy interfaces that it can be invoked through. If the
262 * {@code invoke} method throws a checked exception that is not
263 * assignable to any of the exception types declared by the method in one
264 * of the proxy interfaces that it can be invoked through, then an
265 * unchecked {@code UndeclaredThrowableException} will be thrown by
266 * the invocation on the proxy instance. This restriction means that not
267 * all of the exception types returned by invoking
268 * {@code getExceptionTypes} on the {@code Method} object
269 * passed to the {@code invoke} method can necessarily be thrown
270 * successfully by the {@code invoke} method.
271 *
272 * @author Peter Jones
273 * @see InvocationHandler
274 * @since 1.3
275 */
276 public class Proxy implements java.io.Serializable {
277 private static final long serialVersionUID = -2222568056686623797L;
278
279 /** parameter types of a proxy class constructor */
280 private static final Class<?>[] constructorParams =
281 { InvocationHandler.class };
282
283 /**
284 * a cache of proxy constructors with
285 * {@link Constructor#setAccessible(boolean) accessible} flag already set
286 */
287 private static final ClassLoaderValue<Constructor<?>> proxyCache =
288 new ClassLoaderValue<>();
289
290 /**
291 * the invocation handler for this proxy instance.
292 * @serial
293 */
294 protected InvocationHandler h;
295
296 /**
297 * Prohibits instantiation.
298 */
299 private Proxy() {
300 }
301
302 /**
303 * Constructs a new {@code Proxy} instance from a subclass
304 * (typically, a dynamic proxy class) with the specified value
305 * for its invocation handler.
306 *
307 * @param h the invocation handler for this proxy instance
308 *
309 * @throws NullPointerException if the given invocation handler, {@code h},
310 * is {@code null}.
311 */
312 protected Proxy(InvocationHandler h) {
313 Objects.requireNonNull(h);
314 this.h = h;
315 }
316
317 /**
318 * Returns the {@code java.lang.Class} object for a proxy class
319 * given a class loader and an array of interfaces. The proxy class
320 * will be defined by the specified class loader and will implement
321 * all of the supplied interfaces. If any of the given interfaces
322 * is non-public, the proxy class will be non-public. If a proxy class
323 * for the same permutation of interfaces has already been defined by the
324 * class loader, then the existing proxy class will be returned; otherwise,
325 * a proxy class for those interfaces will be generated dynamically
326 * and defined by the class loader.
327 *
328 * @param loader the class loader to define the proxy class
329 * @param interfaces the list of interfaces for the proxy class
330 * to implement
331 * @return a proxy class that is defined in the specified class loader
332 * and that implements the specified interfaces
333 * @throws IllegalArgumentException if any of the <a href="#restrictions">
334 * restrictions</a> on the parameters are violated
335 * @throws SecurityException if a security manager, <em>s</em>, is present
336 * and any of the following conditions is met:
337 * <ul>
338 * <li> the given {@code loader} is {@code null} and
339 * the caller's class loader is not {@code null} and the
340 * invocation of {@link SecurityManager#checkPermission
341 * s.checkPermission} with
342 * {@code RuntimePermission("getClassLoader")} permission
343 * denies access.</li>
344 * <li> for each proxy interface, {@code intf},
345 * the caller's class loader is not the same as or an
346 * ancestor of the class loader for {@code intf} and
347 * invocation of {@link SecurityManager#checkPackageAccess
348 * s.checkPackageAccess()} denies access to {@code intf}.</li>
349 * </ul>
350 * @throws NullPointerException if the {@code interfaces} array
351 * argument or any of its elements are {@code null}
352 *
353 * @deprecated Proxy classes generated in a named module are encapsulated and not
354 * accessible to code outside its module.
355 * {@link Constructor#newInstance(Object...) Constructor.newInstance} will throw
356 * {@code IllegalAccessException} when it is called on an inaccessible proxy class.
357 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
358 * to create a proxy instance instead.
359 *
360 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
361 */
362 @Deprecated
363 @CallerSensitive
364 public static Class<?> getProxyClass(ClassLoader loader,
365 Class<?>... interfaces)
366 throws IllegalArgumentException
367 {
368 Class<?> caller = System.getSecurityManager() == null
369 ? null
370 : Reflection.getCallerClass();
371
372 return getProxyConstructor(caller, loader, interfaces)
373 .getDeclaringClass();
374 }
375
376 private static Constructor<?> getProxyConstructor(Class<?> caller, // null if no SecurityManager
377 ClassLoader loader,
378 Class<?>... interfaces)
379 throws IllegalArgumentException
380 {
381 // optimization for single interface
382 if (interfaces.length == 1) {
383 Class<?> intf = interfaces[0];
384 if (caller != null) {
385 checkProxyAccess(caller, loader, intf);
386 }
387 return proxyCache.sub(intf).computeIfAbsent(
388 loader,
389 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
390 );
391 } else {
392 // interfaces cloned
393 final Class<?>[] intfsArray = interfaces.clone();
394 if (caller != null) {
395 checkProxyAccess(caller, loader, intfsArray);
396 }
397 final List<Class<?>> intfs = Arrays.asList(intfsArray);
398 return proxyCache.sub(intfs).computeIfAbsent(
399 loader,
400 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
401 );
402 }
403 }
404
405 /*
406 * Check permissions required to create a Proxy class.
407 *
408 * To define a proxy class, it performs the access checks as in
409 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
410 * 1. "getClassLoader" permission check if loader == null
411 * 2. checkPackageAccess on the interfaces it implements
412 *
413 * To get a constructor and new instance of a proxy class, it performs
414 * the package access check on the interfaces it implements
415 * as in Class.getConstructor.
416 *
417 * If an interface is non-public, the proxy class must be defined by
418 * the defining loader of the interface. If the caller's class loader
419 * is not the same as the defining loader of the interface, the VM
420 * will throw IllegalAccessError when the generated proxy class is
421 * being defined.
422 */
423 private static void checkProxyAccess(Class<?> caller,
424 ClassLoader loader,
425 Class<?> ... interfaces)
426 {
427 SecurityManager sm = System.getSecurityManager();
428 if (sm != null) {
429 ClassLoader ccl = caller.getClassLoader();
430 if (VM.isSystemDomainLoader(loader) && !VM.isSystemDomainLoader(ccl)) {
431 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
432 }
433 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
434 }
435 }
436
437 /**
438 * Builder for a proxy class.
439 *
440 * If the module is not specified in this ProxyBuilder constructor,
441 * it will map from the given loader and interfaces to the module
442 * in which the proxy class will be defined.
443 */
444 private static final class ProxyBuilder {
445 private static final Unsafe UNSAFE = Unsafe.getUnsafe();
446
447 // prefix for all proxy class names
448 private static final String proxyClassNamePrefix = "$Proxy";
449
450 // next number to use for generation of unique proxy class names
451 private static final AtomicLong nextUniqueNumber = new AtomicLong();
452
453 // a reverse cache of defined proxy classes
454 private static final ClassLoaderValue<Boolean> reverseProxyCache =
455 new ClassLoaderValue<>();
456
457 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) {
458 String proxyPkg = null; // package to define proxy class in
459 int accessFlags = Modifier.PUBLIC | Modifier.FINAL;
460
461 /*
462 * Record the package of a non-public proxy interface so that the
463 * proxy class will be defined in the same package. Verify that
464 * all non-public proxy interfaces are in the same package.
465 */
466 for (Class<?> intf : interfaces) {
467 int flags = intf.getModifiers();
468 if (!Modifier.isPublic(flags)) {
469 accessFlags = Modifier.FINAL; // non-public, final
470 String pkg = intf.getPackageName();
471 if (proxyPkg == null) {
472 proxyPkg = pkg;
473 } else if (!pkg.equals(proxyPkg)) {
474 throw new IllegalArgumentException(
475 "non-public interfaces from different packages");
476 }
477 }
478 }
479
480 if (proxyPkg == null) {
481 // all proxy interfaces are public
482 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName()
483 : PROXY_PACKAGE_PREFIX;
484 } else if (proxyPkg.isEmpty() && m.isNamed()) {
485 throw new IllegalArgumentException(
486 "Unnamed package cannot be added to " + m);
487 }
488
489 // add the package to the runtime module if not exists
490 if (m.isNamed()) {
491 m.addPackage(proxyPkg);
492 }
493
494 /*
495 * Choose a name for the proxy class to generate.
496 */
497 long num = nextUniqueNumber.getAndIncrement();
498 String proxyName = proxyPkg.isEmpty() ? proxyClassNamePrefix + num
499 : proxyPkg + "." + proxyClassNamePrefix + num;
500
501 ClassLoader loader = getLoader(m);
502 trace(proxyName, m, loader, interfaces);
503
504 /*
505 * Generate the specified proxy class.
506 */
507 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(
508 proxyName, interfaces.toArray(EMPTY_CLASS_ARRAY), accessFlags);
509 try {
510 Class<?> pc = UNSAFE.defineClass(proxyName, proxyClassFile,
511 0, proxyClassFile.length,
512 loader, null);
513 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
514 return pc;
515 } catch (ClassFormatError e) {
516 /*
517 * A ClassFormatError here means that (barring bugs in the
518 * proxy class generation code) there was some other
519 * invalid aspect of the arguments supplied to the proxy
520 * class creation (such as virtual machine limitations
521 * exceeded).
522 */
523 throw new IllegalArgumentException(e.toString());
524 }
525 }
526
527 /**
528 * Test if given class is a class defined by
529 * {@link #defineProxyClass(Module, List)}
530 */
531 static boolean isProxyClass(Class<?> c) {
532 return Boolean.TRUE.equals(
533 reverseProxyCache.sub(c).get(c.getClassLoader()));
534 }
535
536 private static boolean isExportedType(Class<?> c) {
537 String pn = c.getPackageName();
538 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
539 }
540
541 private static boolean isPackagePrivateType(Class<?> c) {
542 return !Modifier.isPublic(c.getModifiers());
543 }
544
545 private static String toDetails(Class<?> c) {
546 String access = "unknown";
547 if (isExportedType(c)) {
548 access = "exported";
549 } else if (isPackagePrivateType(c)) {
550 access = "package-private";
551 } else {
552 access = "module-private";
553 }
554 ClassLoader ld = c.getClassLoader();
555 return String.format(" %s/%s %s loader %s",
556 c.getModule().getName(), c.getName(), access, ld);
557 }
558
559 static void trace(String cn, Module module, ClassLoader loader, List<Class<?>> interfaces) {
560 if (isDebug()) {
561 System.out.format("PROXY: %s/%s defined by %s%n", module.getName(), cn, loader);
562 }
563 if (isDebug("debug")) {
564 interfaces.stream()
565 .forEach(c -> System.out.println(toDetails(c)));
566 }
567 }
568
569 private static final String DEBUG =
570 AccessController.doPrivileged(new PrivilegedAction<>() {
571 public String run() {
572 return System.getProperty("jdk.proxy.debug", "");
573 }
574 });
575
576 private static boolean isDebug() {
577 return !DEBUG.isEmpty();
578 }
579 private static boolean isDebug(String flag) {
580 return DEBUG.equals(flag);
581 }
582
583 // ProxyBuilder instance members start here....
584
585 private final ClassLoader loader;
586 private final List<Class<?>> interfaces;
587 private final Module module;
588 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
589 if (!VM.isModuleSystemInited()) {
590 throw new InternalError("Proxy is not supported until module system is fully initialzed");
591 }
592 if (interfaces.size() > 65535) {
593 throw new IllegalArgumentException("interface limit exceeded");
594 }
595
596 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
597
598 // IAE if violates any restrictions specified in newProxyInstance
599 validateProxyInterfaces(loader, interfaces, refTypes);
600
601 this.loader = loader;
602 this.interfaces = interfaces;
603 this.module = mapToModule(loader, interfaces, refTypes);
604 assert getLoader(module) == loader;
605 }
606
607 ProxyBuilder(ClassLoader loader, Class<?> intf) {
608 this(loader, Collections.singletonList(intf));
609 }
610
611 /**
612 * Generate a proxy class and return its proxy Constructor with
613 * accessible flag already set. If the target module does not have access
614 * to any interface types, IllegalAccessError will be thrown by the VM
615 * at defineClass time.
616 *
617 * Must call the checkProxyAccess method to perform permission checks
618 * before calling this.
619 */
620 Constructor<?> build() {
621 Class<?> proxyClass = defineProxyClass(module, interfaces);
622 final Constructor<?> cons;
623 try {
624 cons = proxyClass.getConstructor(constructorParams);
625 } catch (NoSuchMethodException e) {
626 throw new InternalError(e.toString(), e);
627 }
628 AccessController.doPrivileged(new PrivilegedAction<Void>() {
629 public Void run() {
630 cons.setAccessible(true);
631 return null;
632 }
633 });
634 return cons;
635 }
636
637 /**
638 * Validate the given proxy interfaces and the given referenced types
639 * are visible to the defining loader.
640 *
641 * @throws IllegalArgumentException if it violates the restrictions specified
642 * in {@link Proxy#newProxyInstance}
643 */
644 private static void validateProxyInterfaces(ClassLoader loader,
645 List<Class<?>> interfaces,
646 Set<Class<?>> refTypes)
647 {
648 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
649 for (Class<?> intf : interfaces) {
650 /*
651 * Verify that the class loader resolves the name of this
652 * interface to the same Class object.
653 */
654 ensureVisible(loader, intf);
655
656 /*
657 * Verify that the Class object actually represents an
658 * interface.
659 */
660 if (!intf.isInterface()) {
661 throw new IllegalArgumentException(intf.getName() + " is not an interface");
662 }
663
664 /*
665 * Verify that this interface is not a duplicate.
666 */
667 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
668 throw new IllegalArgumentException("repeated interface: " + intf.getName());
669 }
670 }
671
672 for (Class<?> type : refTypes) {
673 ensureVisible(loader, type);
674 }
675 }
676
677 /*
678 * Returns all types referenced by all public method signatures of
679 * the proxy interfaces
680 */
681 private static Set<Class<?>> referencedTypes(ClassLoader loader,
682 List<Class<?>> interfaces) {
683 return interfaces.stream()
684 .flatMap(intf -> Stream.of(intf.getMethods())
685 .flatMap(ProxyBuilder::methodRefTypes)
686 .map(ProxyBuilder::getElementType)
687 .filter(t -> !t.isPrimitive()))
688 .collect(Collectors.toSet());
689 }
690
691 /*
692 * Extracts all types referenced on a method signature including
693 * its return type, parameter types, and exception types.
694 */
695 private static Stream<Class<?>> methodRefTypes(Method m) {
696 return Stream.of(new Class<?>[] { m.getReturnType() },
697 m.getParameterTypes(),
698 m.getExceptionTypes())
699 .flatMap(Stream::of);
700 }
701
702 /**
703 * Returns the module that the generated proxy class belongs to.
704 *
705 * If all proxy interfaces are public and in exported packages,
706 * then the proxy class is in unnamed module.
707 *
708 * If any of proxy interface is package-private, then the proxy class
709 * is in the same module of the package-private interface.
710 *
711 * If all proxy interfaces are public and at least one in a non-exported
712 * package, then the proxy class is in a dynamic module in a non-exported
713 * package. Reads edge and qualified exports are added for
714 * dynamic module to access.
715 */
716 private static Module mapToModule(ClassLoader loader,
717 List<Class<?>> interfaces,
718 Set<Class<?>> refTypes) {
719 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>();
720 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
721 for (Class<?> intf : interfaces) {
722 Module m = intf.getModule();
723 if (Modifier.isPublic(intf.getModifiers())) {
724 // module-private types
725 if (!m.isExported(intf.getPackageName())) {
726 modulePrivateTypes.put(intf, m);
727 }
728 } else {
729 packagePrivateTypes.put(intf, m);
730 }
731 }
732
733 // all proxy interfaces are public and exported, the proxy class is in unnamed module
734 // Such proxy class is accessible to any unnamed module and named module that
735 // can read unnamed module
736 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) {
737 return loader != null ? loader.getUnnamedModule() : BootLoader.getUnnamedModule();
738 }
739
740 if (packagePrivateTypes.size() > 0) {
741 // all package-private types must be in the same runtime package
742 // i.e. same package name and same module (named or unnamed)
743 //
744 // Configuration will fail if M1 and in M2 defined by the same loader
745 // and both have the same package p (so no need to check class loader)
746 if (packagePrivateTypes.size() > 1 &&
747 (packagePrivateTypes.keySet().stream() // more than one package
748 .map(Class::getPackageName).distinct().count() > 1 ||
749 packagePrivateTypes.values().stream() // or more than one module
750 .distinct().count() > 1)) {
751 throw new IllegalArgumentException(
752 "non-public interfaces from different packages");
753 }
754
755 // all package-private types are in the same module (named or unnamed)
756 Module target = null;
757 for (Module m : packagePrivateTypes.values()) {
758 if (getLoader(m) != loader) {
759 // the specified loader is not the same class loader of the non-public interface
760 throw new IllegalArgumentException(
761 "non-public interface is not defined by the given loader");
762 }
763 target = m;
764 }
765
766 // validate if the target module can access all other interfaces
767 for (Class<?> intf : interfaces) {
768 Module m = intf.getModule();
769 if (m == target) continue;
770
771 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) {
772 throw new IllegalArgumentException(target + " can't access " + intf.getName());
773 }
774 }
775
776 // return the module of the package-private interface
777 return target;
778 }
779
780 // all proxy interfaces are public and at least one in a non-exported package
781 // map to dynamic proxy module and add reads edge and qualified exports, if necessary
782 Module target = getDynamicModule(loader);
783
784 // set up proxy class access to proxy interfaces and superinterfaces
785 Deque<Class<?>> deque = new LinkedList<>(interfaces);
786 Set<Class<?>> visited = new HashSet<>();
787 while (!deque.isEmpty()) {
788 Class<?> c = deque.poll();
789 if (!visited.add(c)) {
790 continue;
791 }
792 ensureAccess(target, c);
793
794 // add all superinterfaces
795 for (Class<?> intf : c.getInterfaces()) {
796 deque.add(intf);
797 }
798 }
799
800 // set up proxy class access to types referenced in the method signature
801 refTypes.stream()
802 .filter(t -> !visited.contains(t))
803 .forEach(t -> ensureAccess(target, t));
804 return target;
805 }
806
807 /*
808 * Ensure the given module can access the given class.
809 */
810 private static void ensureAccess(Module target, Class<?> c) {
811 Module m = c.getModule();
812 // add read edge and qualified export for the target module to access
813 if (!target.canRead(m)) {
814 Modules.addReads(target, m);
815 }
816 String pn = c.getPackageName();
817 if (!m.isExported(pn, target)) {
818 Modules.addExports(m, pn, target);
819 }
820 }
821
822 /*
823 * Ensure the given class is visible to the class loader.
824 */
825 private static void ensureVisible(ClassLoader ld, Class<?> c) {
826 Class<?> type = null;
827 try {
828 type = Class.forName(c.getName(), false, ld);
829 } catch (ClassNotFoundException e) {
830 }
831 if (type != c) {
832 throw new IllegalArgumentException(c.getName() +
833 " referenced from a method is not visible from class loader");
834 }
835 }
836
837 private static Class<?> getElementType(Class<?> type) {
838 Class<?> e = type;
839 while (e.isArray()) {
840 e = e.getComponentType();
841 }
842 return e;
843 }
844
845 private static final ClassLoaderValue<Module> dynProxyModules =
846 new ClassLoaderValue<>();
847 private static final AtomicInteger counter = new AtomicInteger();
848
849 /*
850 * Define a dynamic module for the generated proxy classes in a non-exported package
851 * named com.sun.proxy.$MODULE.
852 *
853 * Each class loader will have one dynamic module.
854 */
855 private static Module getDynamicModule(ClassLoader loader) {
856 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
857 // create a dynamic module and setup module access
858 String mn = "jdk.proxy" + counter.incrementAndGet();
859 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
860 Module m = Modules.defineModule(ld, mn, Collections.singleton(pn));
861 Modules.addReads(m, Proxy.class.getModule());
862 // java.base to create proxy instance
863 Modules.addExports(m, pn, Object.class.getModule());
864 return m;
865 });
866 }
867 }
868
869 /**
870 * Returns a proxy instance for the specified interfaces
871 * that dispatches method invocations to the specified invocation
872 * handler.
873 * <p>
874 * <a name="restrictions">{@code IllegalArgumentException} will be thrown
875 * if any of the following restrictions is violated:</a>
876 * <ul>
877 * <li>All of {@code Class} objects in the given {@code interfaces} array
878 * must represent interfaces, not classes or primitive types.
879 *
880 * <li>No two elements in the {@code interfaces} array may
881 * refer to identical {@code Class} objects.
882 *
883 * <li>All of the interface types must be visible by name through the
884 * specified class loader. In other words, for class loader
885 * {@code cl} and every interface {@code i}, the following
886 * expression must be true:<p>
887 * {@code Class.forName(i.getName(), false, cl) == i}
888 *
889 * <li>All of the types referenced by all
890 * public method signatures of the specified interfaces
891 * and those inherited by their superinterfaces
892 * must be visible by name through the specified class loader.
893 *
894 * <li>All non-public interfaces must be in the same package
895 * and module, defined by the specified class loader and
896 * the module of the non-public interfaces can access all of
897 * the interface types; otherwise, it would not be possible for
898 * the proxy class to implement all of the interfaces,
899 * regardless of what package it is defined in.
900 *
901 * <li>For any set of member methods of the specified interfaces
902 * that have the same signature:
903 * <ul>
904 * <li>If the return type of any of the methods is a primitive
905 * type or void, then all of the methods must have that same
906 * return type.
907 * <li>Otherwise, one of the methods must have a return type that
908 * is assignable to all of the return types of the rest of the
909 * methods.
910 * </ul>
911 *
912 * <li>The resulting proxy class must not exceed any limits imposed
913 * on classes by the virtual machine. For example, the VM may limit
914 * the number of interfaces that a class may implement to 65535; in
915 * that case, the size of the {@code interfaces} array must not
916 * exceed 65535.
917 * </ul>
918 *
919 * <p>Note that the order of the specified proxy interfaces is
920 * significant: two requests for a proxy class with the same combination
921 * of interfaces but in a different order will result in two distinct
922 * proxy classes.
923 *
924 * @param loader the class loader to define the proxy class
925 * @param interfaces the list of interfaces for the proxy class
926 * to implement
927 * @param h the invocation handler to dispatch method invocations to
928 * @return a proxy instance with the specified invocation handler of a
929 * proxy class that is defined by the specified class loader
930 * and that implements the specified interfaces
931 * @throws IllegalArgumentException if any of the <a href="#restrictions">
932 * restrictions</a> on the parameters are violated
933 * @throws SecurityException if a security manager, <em>s</em>, is present
934 * and any of the following conditions is met:
935 * <ul>
936 * <li> the given {@code loader} is {@code null} and
937 * the caller's class loader is not {@code null} and the
938 * invocation of {@link SecurityManager#checkPermission
939 * s.checkPermission} with
940 * {@code RuntimePermission("getClassLoader")} permission
941 * denies access;</li>
942 * <li> for each proxy interface, {@code intf},
943 * the caller's class loader is not the same as or an
944 * ancestor of the class loader for {@code intf} and
945 * invocation of {@link SecurityManager#checkPackageAccess
946 * s.checkPackageAccess()} denies access to {@code intf};</li>
947 * <li> any of the given proxy interfaces is non-public and the
948 * caller class is not in the same {@linkplain Package runtime package}
949 * as the non-public interface and the invocation of
950 * {@link SecurityManager#checkPermission s.checkPermission} with
951 * {@code ReflectPermission("newProxyInPackage.{package name}")}
952 * permission denies access.</li>
953 * </ul>
954 * @throws NullPointerException if the {@code interfaces} array
955 * argument or any of its elements are {@code null}, or
956 * if the invocation handler, {@code h}, is
957 * {@code null}
958 *
959 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
960 */
961 @CallerSensitive
962 public static Object newProxyInstance(ClassLoader loader,
963 Class<?>[] interfaces,
964 InvocationHandler h) {
965 Objects.requireNonNull(h);
966
967 final Class<?> caller = System.getSecurityManager() == null
968 ? null
969 : Reflection.getCallerClass();
970
971 /*
972 * Look up or generate the designated proxy class and its constructor.
973 */
974 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
975
976 return newProxyInstance(caller, cons, h);
977 }
978
979 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
980 Constructor<?> cons,
981 InvocationHandler h) {
982 /*
983 * Invoke its constructor with the designated invocation handler.
984 */
985 try {
986 if (caller != null) {
987 checkNewProxyPermission(caller, cons.getDeclaringClass());
988 }
989
990 return cons.newInstance(new Object[]{h});
991 } catch (IllegalAccessException | InstantiationException e) {
992 throw new InternalError(e.toString(), e);
993 } catch (InvocationTargetException e) {
994 Throwable t = e.getCause();
995 if (t instanceof RuntimeException) {
996 throw (RuntimeException) t;
997 } else {
998 throw new InternalError(t.toString(), t);
999 }
1000 }
1001 }
1002
1003 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1004 SecurityManager sm = System.getSecurityManager();
1005 if (sm != null) {
1006 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1007 ClassLoader ccl = caller.getClassLoader();
1008 ClassLoader pcl = proxyClass.getClassLoader();
1009
1010 // do permission check if the caller is in a different runtime package
1011 // of the proxy class
1012 int n = proxyClass.getName().lastIndexOf('.');
1013 String pkg = (n == -1) ? "" : proxyClass.getName().substring(0, n);
1014
1015 n = caller.getName().lastIndexOf('.');
1016 String callerPkg = (n == -1) ? "" : caller.getName().substring(0, n);
1017
1018 if (pcl != ccl || !pkg.equals(callerPkg)) {
1019 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1020 }
1021 }
1022 }
1023 }
1024
1025 /**
1026 * Returns the class loader for the given module.
1027 */
1028 private static ClassLoader getLoader(Module m) {
1029 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1030 return AccessController.doPrivileged(pa);
1031 }
1032
1033 /**
1034 * Returns true if the given class is a proxy class.
1035 *
1036 * @implNote The reliability of this method is important for the ability
1037 * to use it to make security decisions, so its implementation should
1038 * not just test if the class in question extends {@code Proxy}.
1039 *
1040 * @param cl the class to test
1041 * @return {@code true} if the class is a proxy class and
1042 * {@code false} otherwise
1043 * @throws NullPointerException if {@code cl} is {@code null}
1044 */
1045 public static boolean isProxyClass(Class<?> cl) {
1046 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1047 }
1048
1049 /**
1050 * Returns the invocation handler for the specified proxy instance.
1051 *
1052 * @param proxy the proxy instance to return the invocation handler for
1053 * @return the invocation handler for the proxy instance
1054 * @throws IllegalArgumentException if the argument is not a
1055 * proxy instance
1056 * @throws SecurityException if a security manager, <em>s</em>, is present
1057 * and the caller's class loader is not the same as or an
1058 * ancestor of the class loader for the invocation handler
1059 * and invocation of {@link SecurityManager#checkPackageAccess
1060 * s.checkPackageAccess()} denies access to the invocation
1061 * handler's class.
1062 */
1063 @CallerSensitive
1064 public static InvocationHandler getInvocationHandler(Object proxy)
1065 throws IllegalArgumentException
1066 {
1067 /*
1068 * Verify that the object is actually a proxy instance.
1069 */
1070 if (!isProxyClass(proxy.getClass())) {
1071 throw new IllegalArgumentException("not a proxy instance");
1072 }
1073
1074 final Proxy p = (Proxy) proxy;
1075 final InvocationHandler ih = p.h;
1076 if (System.getSecurityManager() != null) {
1077 Class<?> ihClass = ih.getClass();
1078 Class<?> caller = Reflection.getCallerClass();
1079 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1080 ihClass.getClassLoader()))
1081 {
1082 ReflectUtil.checkPackageAccess(ihClass);
1083 }
1084 }
1085
1086 return ih;
1087 }
1088
1089 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
1090 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1091 }