1 /*
2 * Copyright (c) 1999, 2017, 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.loader.BootLoader;
44 import jdk.internal.misc.JavaLangAccess;
45 import jdk.internal.misc.SharedSecrets;
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.GetPropertyAction;
53 import sun.security.util.SecurityConstants;
54
55 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC;
56
57
58 /**
59 *
60 * {@code Proxy} provides static methods for creating objects that act like instances
61 * of interfaces but allow for customized method invocation.
62 * To create a proxy instance for some interface {@code Foo}:
63 * <pre>{@code
64 * InvocationHandler handler = new MyInvocationHandler(...);
65 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
66 * new Class<?>[] { Foo.class },
67 * handler);
68 * }</pre>
69 *
70 * <p>
71 * A <em>proxy class</em> is a class created at runtime that implements a specified
72 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em>
73 * is an instance of a proxy class.
74 *
75 * Each proxy instance has an associated <i>invocation handler</i>
76 * object, which implements the interface {@link InvocationHandler}.
77 * A method invocation on a proxy instance through one of its proxy
78 * interfaces will be dispatched to the {@link InvocationHandler#invoke
79 * invoke} method of the instance's invocation handler, passing the proxy
80 * instance, a {@code java.lang.reflect.Method} object identifying
81 * the method that was invoked, and an array of type {@code Object}
82 * containing the arguments. The invocation handler processes the
83 * encoded method invocation as appropriate and the result that it
84 * returns will be returned as the result of the method invocation on
85 * the proxy instance.
86 *
87 * <p>A proxy class has the following properties:
88 *
89 * <ul>
90 * <li>The unqualified name of a proxy class is unspecified. The space
91 * of class names that begin with the string {@code "$Proxy"}
92 * should be, however, reserved for proxy classes.
93 *
94 * <li>The package and module in which a proxy class is defined is specified
95 * <a href="#membership">below</a>.
96 *
97 * <li>A proxy class is <em>final and non-abstract</em>.
98 *
99 * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
100 *
101 * <li>A proxy class implements exactly the interfaces specified at its
102 * creation, in the same order. Invoking {@link Class#getInterfaces getInterfaces}
103 * on its {@code Class} object will return an array containing the same
104 * list of interfaces (in the order specified at its creation), invoking
105 * {@link Class#getMethods getMethods} on its {@code Class} object will return
106 * an array of {@code Method} objects that include all of the
107 * methods in those interfaces, and invoking {@code getMethod} will
108 * find methods in the proxy interfaces as would be expected.
109 *
110 * <li>The {@link java.security.ProtectionDomain} of a proxy class
111 * is the same as that of system classes loaded by the bootstrap class
112 * loader, such as {@code java.lang.Object}, because the code for a
113 * proxy class is generated by trusted system code. This protection
114 * domain will typically be granted {@code java.security.AllPermission}.
115 *
116 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used
117 * to determine if a given class is a proxy class.
118 * </ul>
119 *
120 * <p>A proxy instance has the following properties:
121 *
122 * <ul>
123 * <li>Given a proxy instance {@code proxy} and one of the
124 * interfaces, {@code Foo}, implemented by its proxy class, the
125 * following expression will return true:
126 * <pre>
127 * {@code proxy instanceof Foo}
128 * </pre>
129 * and the following cast operation will succeed (rather than throwing
130 * a {@code ClassCastException}):
131 * <pre>
132 * {@code (Foo) proxy}
133 * </pre>
134 *
135 * <li>Each proxy instance has an associated invocation handler, the one
136 * that was passed to its constructor. The static
137 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
138 * will return the invocation handler associated with the proxy instance
139 * passed as its argument.
140 *
141 * <li>An interface method invocation on a proxy instance will be
142 * encoded and dispatched to the invocation handler's {@link
143 * InvocationHandler#invoke invoke} method as described in the
144 * documentation for that method.
145 *
146 * <li>An invocation of the {@code hashCode},
147 * {@code equals}, or {@code toString} methods declared in
148 * {@code java.lang.Object} on a proxy instance will be encoded and
149 * dispatched to the invocation handler's {@code invoke} method in
150 * the same manner as interface method invocations are encoded and
151 * dispatched, as described above. The declaring class of the
152 * {@code Method} object passed to {@code invoke} will be
153 * {@code java.lang.Object}. Other public methods of a proxy
154 * instance inherited from {@code java.lang.Object} are not
155 * overridden by a proxy class, so invocations of those methods behave
156 * like they do for instances of {@code java.lang.Object}.
157 * </ul>
158 *
159 * <h3><a id="membership">Package and Module Membership of Proxy Class</a></h3>
160 *
161 * The package and module to which a proxy class belongs are chosen such that
162 * the accessibility of the proxy class is in line with the accessibility of
163 * the proxy interfaces. Specifically, the package and the module membership
164 * of a proxy class defined via the
165 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or
166 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)}
167 * methods is specified as follows:
168 *
169 * <ol>
170 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em>
171 * packages:
172 * <ol type="a">
173 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
174 * <em>public</em> in a package exported by the
175 * {@linkplain ClassLoader#getUnnamedModule() unnamed module} of the specified
176 * loader. The name of the package is unspecified.</li>
177 *
178 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
179 * the proxy class is <em>non-public</em> in the package and module of the
180 * non-public interfaces. All the non-public interfaces must be in the same
181 * package and module; otherwise, proxying them is
182 * <a href="#restrictions">not possible</a>.</li>
183 * </ol>
184 * </li>
185 * <li>If at least one proxy interface is in a package that is
186 * <em>non-exported</em> and <em>non-open</em>:
187 * <ol type="a">
188 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
189 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of
190 * <a href="#dynamicmodule"><em>dynamic module</em>.</a>
191 * The names of the package and the module are unspecified.</li>
192 *
193 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
194 * the proxy class is <em>non-public</em> in the package and module of the
195 * non-public interfaces. All the non-public interfaces must be in the same
196 * package and module; otherwise, proxying them is
197 * <a href="#restrictions">not possible</a>.</li>
198 * </ol>
199 * </li>
200 * </ol>
201 *
202 * <p>
203 * Note that if proxy interfaces with a mix of accessibilities -- for example,
204 * an exported public interface and a non-exported non-public interface -- are
205 * proxied by the same instance, then the proxy class's accessibility is
206 * governed by the least accessible proxy interface.
207 * <p>
208 * Note that it is possible for arbitrary code to obtain access to a proxy class
209 * in an open package with {@link AccessibleObject#setAccessible setAccessible},
210 * whereas a proxy class in a non-open package is never accessible to
211 * code outside the module of the proxy class.
212 *
213 * <p>
214 * Throughout this specification, a "non-exported package" refers to a package
215 * that is not exported to all modules, and a "non-open package" refers to
216 * a package that is not open to all modules. Specifically, these terms refer to
217 * a package that either is not exported/open by its containing module or is
218 * exported/open in a qualified fashion by its containing module.
219 *
220 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3>
221 * <p>
222 * A dynamic module is a named module generated at runtime. A proxy class
223 * defined in a dynamic module is encapsulated and not accessible to any module.
224 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in
225 * a dynamic module will throw {@code IllegalAccessException};
226 * {@code Proxy.newProxyInstance} method should be used instead.
227 *
228 * <p>
229 * A dynamic module can read the modules of all of the superinterfaces of a proxy
230 * class and the modules of the types referenced by all public method signatures
231 * of a proxy class. If a superinterface or a referenced type, say {@code T},
232 * is in a non-exported package, the {@linkplain Module module} of {@code T} is
233 * updated to export the package of {@code T} to the dynamic module.
234 *
235 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
236 *
237 * <p>When two or more proxy interfaces contain a method with
238 * the same name and parameter signature, the order of the proxy class's
239 * interfaces becomes significant. When such a <i>duplicate method</i>
240 * is invoked on a proxy instance, the {@code Method} object passed
241 * to the invocation handler will not necessarily be the one whose
242 * declaring class is assignable from the reference type of the interface
243 * that the proxy's method was invoked through. This limitation exists
244 * because the corresponding method implementation in the generated proxy
245 * class cannot determine which interface it was invoked through.
246 * Therefore, when a duplicate method is invoked on a proxy instance,
247 * the {@code Method} object for the method in the foremost interface
248 * that contains the method (either directly or inherited through a
249 * superinterface) in the proxy class's list of interfaces is passed to
250 * the invocation handler's {@code invoke} method, regardless of the
251 * reference type through which the method invocation occurred.
252 *
253 * <p>If a proxy interface contains a method with the same name and
254 * parameter signature as the {@code hashCode}, {@code equals},
255 * or {@code toString} methods of {@code java.lang.Object},
256 * when such a method is invoked on a proxy instance, the
257 * {@code Method} object passed to the invocation handler will have
258 * {@code java.lang.Object} as its declaring class. In other words,
259 * the public, non-final methods of {@code java.lang.Object}
260 * logically precede all of the proxy interfaces for the determination of
261 * which {@code Method} object to pass to the invocation handler.
262 *
263 * <p>Note also that when a duplicate method is dispatched to an
264 * invocation handler, the {@code invoke} method may only throw
265 * checked exception types that are assignable to one of the exception
266 * types in the {@code throws} clause of the method in <i>all</i> of
267 * the proxy interfaces that it can be invoked through. If the
268 * {@code invoke} method throws a checked exception that is not
269 * assignable to any of the exception types declared by the method in one
270 * of the proxy interfaces that it can be invoked through, then an
271 * unchecked {@code UndeclaredThrowableException} will be thrown by
272 * the invocation on the proxy instance. This restriction means that not
273 * all of the exception types returned by invoking
274 * {@code getExceptionTypes} on the {@code Method} object
275 * passed to the {@code invoke} method can necessarily be thrown
276 * successfully by the {@code invoke} method.
277 *
278 * @author Peter Jones
279 * @see InvocationHandler
280 * @since 1.3
281 * @revised 9
282 * @spec JPMS
283 */
284 public class Proxy implements java.io.Serializable {
285 private static final long serialVersionUID = -2222568056686623797L;
286
287 /** parameter types of a proxy class constructor */
288 private static final Class<?>[] constructorParams =
289 { InvocationHandler.class };
290
291 /**
292 * a cache of proxy constructors with
293 * {@link Constructor#setAccessible(boolean) accessible} flag already set
294 */
295 private static final ClassLoaderValue<Constructor<?>> proxyCache =
296 new ClassLoaderValue<>();
297
298 /**
299 * the invocation handler for this proxy instance.
300 * @serial
301 */
302 protected InvocationHandler h;
303
304 /**
305 * Prohibits instantiation.
306 */
307 private Proxy() {
308 }
309
310 /**
311 * Constructs a new {@code Proxy} instance from a subclass
312 * (typically, a dynamic proxy class) with the specified value
313 * for its invocation handler.
314 *
315 * @param h the invocation handler for this proxy instance
316 *
317 * @throws NullPointerException if the given invocation handler, {@code h},
318 * is {@code null}.
319 */
320 protected Proxy(InvocationHandler h) {
321 Objects.requireNonNull(h);
322 this.h = h;
323 }
324
325 /**
326 * Returns the {@code java.lang.Class} object for a proxy class
327 * given a class loader and an array of interfaces. The proxy class
328 * will be defined by the specified class loader and will implement
329 * all of the supplied interfaces. If any of the given interfaces
330 * is non-public, the proxy class will be non-public. If a proxy class
331 * for the same permutation of interfaces has already been defined by the
332 * class loader, then the existing proxy class will be returned; otherwise,
333 * a proxy class for those interfaces will be generated dynamically
334 * and defined by the class loader.
335 *
336 * @param loader the class loader to define the proxy class
337 * @param interfaces the list of interfaces for the proxy class
338 * to implement
339 * @return a proxy class that is defined in the specified class loader
340 * and that implements the specified interfaces
341 * @throws IllegalArgumentException if any of the <a href="#restrictions">
342 * restrictions</a> on the parameters are violated
343 * @throws SecurityException if a security manager, <em>s</em>, is present
344 * and any of the following conditions is met:
345 * <ul>
346 * <li> the given {@code loader} is {@code null} and
347 * the caller's class loader is not {@code null} and the
348 * invocation of {@link SecurityManager#checkPermission
349 * s.checkPermission} with
350 * {@code RuntimePermission("getClassLoader")} permission
351 * denies access.</li>
352 * <li> for each proxy interface, {@code intf},
353 * the caller's class loader is not the same as or an
354 * ancestor of the class loader for {@code intf} and
355 * invocation of {@link SecurityManager#checkPackageAccess
356 * s.checkPackageAccess()} denies access to {@code intf}.</li>
357 * </ul>
358 * @throws NullPointerException if the {@code interfaces} array
359 * argument or any of its elements are {@code null}
360 *
361 * @deprecated Proxy classes generated in a named module are encapsulated
362 * and not accessible to code outside its module.
363 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
364 * will throw {@code IllegalAccessException} when it is called on
365 * an inaccessible proxy class.
366 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
367 * to create a proxy instance instead.
368 *
369 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
370 * @revised 9
371 * @spec JPMS
372 */
373 @Deprecated
374 @CallerSensitive
375 public static Class<?> getProxyClass(ClassLoader loader,
376 Class<?>... interfaces)
377 throws IllegalArgumentException
378 {
379 Class<?> caller = System.getSecurityManager() == null
380 ? null
381 : Reflection.getCallerClass();
382
383 return getProxyConstructor(caller, loader, interfaces)
384 .getDeclaringClass();
385 }
386
387 /**
388 * Returns the {@code Constructor} object of a proxy class that takes a
389 * single argument of type {@link InvocationHandler}, given a class loader
390 * and an array of interfaces. The returned constructor will have the
391 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
392 *
393 * @param caller passed from a public-facing @CallerSensitive method if
394 * SecurityManager is set or {@code null} if there's no
395 * SecurityManager
396 * @param loader the class loader to define the proxy class
397 * @param interfaces the list of interfaces for the proxy class
398 * to implement
399 * @return a Constructor of the proxy class taking single
400 * {@code InvocationHandler} parameter
401 */
402 private static Constructor<?> getProxyConstructor(Class<?> caller,
403 ClassLoader loader,
404 Class<?>... interfaces)
405 {
406 // optimization for single interface
407 if (interfaces.length == 1) {
408 Class<?> intf = interfaces[0];
409 if (caller != null) {
410 checkProxyAccess(caller, loader, intf);
411 }
412 return proxyCache.sub(intf).computeIfAbsent(
413 loader,
414 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
415 );
416 } else {
417 // interfaces cloned
418 final Class<?>[] intfsArray = interfaces.clone();
419 if (caller != null) {
420 checkProxyAccess(caller, loader, intfsArray);
421 }
422 final List<Class<?>> intfs = Arrays.asList(intfsArray);
423 return proxyCache.sub(intfs).computeIfAbsent(
424 loader,
425 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
426 );
427 }
428 }
429
430 /*
431 * Check permissions required to create a Proxy class.
432 *
433 * To define a proxy class, it performs the access checks as in
434 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
435 * 1. "getClassLoader" permission check if loader == null
436 * 2. checkPackageAccess on the interfaces it implements
437 *
438 * To get a constructor and new instance of a proxy class, it performs
439 * the package access check on the interfaces it implements
440 * as in Class.getConstructor.
441 *
442 * If an interface is non-public, the proxy class must be defined by
443 * the defining loader of the interface. If the caller's class loader
444 * is not the same as the defining loader of the interface, the VM
445 * will throw IllegalAccessError when the generated proxy class is
446 * being defined.
447 */
448 private static void checkProxyAccess(Class<?> caller,
449 ClassLoader loader,
450 Class<?> ... interfaces)
451 {
452 SecurityManager sm = System.getSecurityManager();
453 if (sm != null) {
454 ClassLoader ccl = caller.getClassLoader();
455 if (loader == null && ccl != null) {
456 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
457 }
458 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
459 }
460 }
461
462 /**
463 * Builder for a proxy class.
464 *
465 * If the module is not specified in this ProxyBuilder constructor,
466 * it will map from the given loader and interfaces to the module
467 * in which the proxy class will be defined.
468 */
469 private static final class ProxyBuilder {
470 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
471
472 // prefix for all proxy class names
473 private static final String proxyClassNamePrefix = "$Proxy";
474
475 // next number to use for generation of unique proxy class names
476 private static final AtomicLong nextUniqueNumber = new AtomicLong();
477
478 // a reverse cache of defined proxy classes
479 private static final ClassLoaderValue<Boolean> reverseProxyCache =
480 new ClassLoaderValue<>();
481
482 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) {
483 String proxyPkg = null; // package to define proxy class in
484 int accessFlags = Modifier.PUBLIC | Modifier.FINAL;
485
486 /*
487 * Record the package of a non-public proxy interface so that the
488 * proxy class will be defined in the same package. Verify that
489 * all non-public proxy interfaces are in the same package.
490 */
491 for (Class<?> intf : interfaces) {
492 int flags = intf.getModifiers();
493 if (!Modifier.isPublic(flags)) {
494 accessFlags = Modifier.FINAL; // non-public, final
495 String pkg = intf.getPackageName();
496 if (proxyPkg == null) {
497 proxyPkg = pkg;
498 } else if (!pkg.equals(proxyPkg)) {
499 throw new IllegalArgumentException(
500 "non-public interfaces from different packages");
501 }
502 }
503 }
504
505 if (proxyPkg == null) {
506 // all proxy interfaces are public
507 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName()
508 : PROXY_PACKAGE_PREFIX;
509 } else if (proxyPkg.isEmpty() && m.isNamed()) {
510 throw new IllegalArgumentException(
511 "Unnamed package cannot be added to " + m);
512 }
513
514 if (m.isNamed()) {
515 if (!m.getDescriptor().packages().contains(proxyPkg)) {
516 throw new InternalError(proxyPkg + " not exist in " + m.getName());
517 }
518 }
519
520 /*
521 * Choose a name for the proxy class to generate.
522 */
523 long num = nextUniqueNumber.getAndIncrement();
524 String proxyName = proxyPkg.isEmpty()
525 ? proxyClassNamePrefix + num
526 : proxyPkg + "." + proxyClassNamePrefix + num;
527
528 ClassLoader loader = getLoader(m);
529 trace(proxyName, m, loader, interfaces);
530
531 /*
532 * Generate the specified proxy class.
533 */
534 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(
535 proxyName, interfaces.toArray(EMPTY_CLASS_ARRAY), accessFlags);
536 try {
537 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
538 null, "__dynamic_proxy__");
539 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
540 return pc;
541 } catch (ClassFormatError e) {
542 /*
543 * A ClassFormatError here means that (barring bugs in the
544 * proxy class generation code) there was some other
545 * invalid aspect of the arguments supplied to the proxy
546 * class creation (such as virtual machine limitations
547 * exceeded).
548 */
549 throw new IllegalArgumentException(e.toString());
550 }
551 }
552
553 /**
554 * Test if given class is a class defined by
555 * {@link #defineProxyClass(Module, List)}
556 */
557 static boolean isProxyClass(Class<?> c) {
558 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
559 Boolean.TRUE);
560 }
561
562 private static boolean isExportedType(Class<?> c) {
563 String pn = c.getPackageName();
564 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
565 }
566
567 private static boolean isPackagePrivateType(Class<?> c) {
568 return !Modifier.isPublic(c.getModifiers());
569 }
570
571 private static String toDetails(Class<?> c) {
572 String access = "unknown";
573 if (isExportedType(c)) {
574 access = "exported";
575 } else if (isPackagePrivateType(c)) {
576 access = "package-private";
577 } else {
578 access = "module-private";
579 }
580 ClassLoader ld = c.getClassLoader();
581 return String.format(" %s/%s %s loader %s",
582 c.getModule().getName(), c.getName(), access, ld);
583 }
584
585 static void trace(String cn,
586 Module module,
587 ClassLoader loader,
588 List<Class<?>> interfaces) {
589 if (isDebug()) {
590 System.err.format("PROXY: %s/%s defined by %s%n",
591 module.getName(), cn, loader);
592 }
593 if (isDebug("debug")) {
594 interfaces.forEach(c -> System.out.println(toDetails(c)));
595 }
596 }
597
598 private static final String DEBUG =
599 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
600
601 private static boolean isDebug() {
602 return !DEBUG.isEmpty();
603 }
604 private static boolean isDebug(String flag) {
605 return DEBUG.equals(flag);
606 }
607
608 // ProxyBuilder instance members start here....
609
610 private final List<Class<?>> interfaces;
611 private final Module module;
612 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
613 if (!VM.isModuleSystemInited()) {
614 throw new InternalError("Proxy is not supported until "
615 + "module system is fully initialized");
616 }
617 if (interfaces.size() > 65535) {
618 throw new IllegalArgumentException("interface limit exceeded: "
619 + interfaces.size());
620 }
621
622 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
623
624 // IAE if violates any restrictions specified in newProxyInstance
625 validateProxyInterfaces(loader, interfaces, refTypes);
626
627 this.interfaces = interfaces;
628 this.module = mapToModule(loader, interfaces, refTypes);
629 assert getLoader(module) == loader;
630 }
631
632 ProxyBuilder(ClassLoader loader, Class<?> intf) {
633 this(loader, Collections.singletonList(intf));
634 }
635
636 /**
637 * Generate a proxy class and return its proxy Constructor with
638 * accessible flag already set. If the target module does not have access
639 * to any interface types, IllegalAccessError will be thrown by the VM
640 * at defineClass time.
641 *
642 * Must call the checkProxyAccess method to perform permission checks
643 * before calling this.
644 */
645 Constructor<?> build() {
646 Class<?> proxyClass = defineProxyClass(module, interfaces);
647 final Constructor<?> cons;
648 try {
649 cons = proxyClass.getConstructor(constructorParams);
650 } catch (NoSuchMethodException e) {
651 throw new InternalError(e.toString(), e);
652 }
653 AccessController.doPrivileged(new PrivilegedAction<Void>() {
654 public Void run() {
655 cons.setAccessible(true);
656 return null;
657 }
658 });
659 return cons;
660 }
661
662 /**
663 * Validate the given proxy interfaces and the given referenced types
664 * are visible to the defining loader.
665 *
666 * @throws IllegalArgumentException if it violates the restrictions
667 * specified in {@link Proxy#newProxyInstance}
668 */
669 private static void validateProxyInterfaces(ClassLoader loader,
670 List<Class<?>> interfaces,
671 Set<Class<?>> refTypes)
672 {
673 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
674 for (Class<?> intf : interfaces) {
675 /*
676 * Verify that the class loader resolves the name of this
677 * interface to the same Class object.
678 */
679 ensureVisible(loader, intf);
680
681 /*
682 * Verify that the Class object actually represents an
683 * interface.
684 */
685 if (!intf.isInterface()) {
686 throw new IllegalArgumentException(intf.getName() + " is not an interface");
687 }
688
689 /*
690 * Verify that this interface is not a duplicate.
691 */
692 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
693 throw new IllegalArgumentException("repeated interface: " + intf.getName());
694 }
695 }
696
697 for (Class<?> type : refTypes) {
698 ensureVisible(loader, type);
699 }
700 }
701
702 /*
703 * Returns all types referenced by all public non-static method signatures of
704 * the proxy interfaces
705 */
706 private static Set<Class<?>> referencedTypes(ClassLoader loader,
707 List<Class<?>> interfaces) {
708 var types = new HashSet<Class<?>>();
709 for (var intf : interfaces) {
710 for (Method m : intf.getMethods()) {
711 if (!Modifier.isStatic(m.getModifiers())) {
712 addElementType(types, m.getReturnType());
713 addElementTypes(types, m.getSharedParameterTypes());
714 addElementTypes(types, m.getSharedExceptionTypes());
715 }
716 }
717 }
718 return types;
719 }
720
721 private static void addElementTypes(HashSet<Class<?>> types,
722 Class<?> ... classes) {
723 for (var cls : classes) {
724 addElementType(types, cls);
725 }
726 }
727
728 private static void addElementType(HashSet<Class<?>> types,
729 Class<?> cls) {
730 var type = getElementType(cls);
731 if (!type.isPrimitive()) {
732 types.add(type);
733 }
734 }
735
736 /**
737 * Returns the module that the generated proxy class belongs to.
738 *
739 * If all proxy interfaces are public and in exported packages,
740 * then the proxy class is in unnamed module.
741 *
742 * If any of proxy interface is package-private, then the proxy class
743 * is in the same module of the package-private interface.
744 *
745 * If all proxy interfaces are public and at least one in a non-exported
746 * package, then the proxy class is in a dynamic module in a
747 * non-exported package. Reads edge and qualified exports are added
748 * for dynamic module to access.
749 */
750 private static Module mapToModule(ClassLoader loader,
751 List<Class<?>> interfaces,
752 Set<Class<?>> refTypes) {
753 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>();
754 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
755 for (Class<?> intf : interfaces) {
756 Module m = intf.getModule();
757 if (Modifier.isPublic(intf.getModifiers())) {
758 // module-private types
759 if (!m.isExported(intf.getPackageName())) {
760 modulePrivateTypes.put(intf, m);
761 }
762 } else {
763 packagePrivateTypes.put(intf, m);
764 }
765 }
766
767 // all proxy interfaces are public and exported, the proxy class
768 // is in unnamed module. Such proxy class is accessible to
769 // any unnamed module and named module that can read unnamed module
770 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) {
771 return loader != null ? loader.getUnnamedModule()
772 : BootLoader.getUnnamedModule();
773 }
774
775 if (packagePrivateTypes.size() > 0) {
776 // all package-private types must be in the same runtime package
777 // i.e. same package name and same module (named or unnamed)
778 //
779 // Configuration will fail if M1 and in M2 defined by the same loader
780 // and both have the same package p (so no need to check class loader)
781 if (packagePrivateTypes.size() > 1 &&
782 (packagePrivateTypes.keySet().stream() // more than one package
783 .map(Class::getPackageName).distinct().count() > 1 ||
784 packagePrivateTypes.values().stream() // or more than one module
785 .distinct().count() > 1)) {
786 throw new IllegalArgumentException(
787 "non-public interfaces from different packages");
788 }
789
790 // all package-private types are in the same module (named or unnamed)
791 Module target = null;
792 for (Module m : packagePrivateTypes.values()) {
793 if (getLoader(m) != loader) {
794 // the specified loader is not the same class loader
795 // of the non-public interface
796 throw new IllegalArgumentException(
797 "non-public interface is not defined by the given loader");
798 }
799 target = m;
800 }
801
802 // validate if the target module can access all other interfaces
803 for (Class<?> intf : interfaces) {
804 Module m = intf.getModule();
805 if (m == target) continue;
806
807 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) {
808 throw new IllegalArgumentException(target + " can't access " + intf.getName());
809 }
810 }
811
812 // return the module of the package-private interface
813 return target;
814 }
815
816 // All proxy interfaces are public and at least one in a non-exported
817 // package. So maps to a dynamic proxy module and add reads edge
818 // and qualified exports, if necessary
819 Module target = getDynamicModule(loader);
820
821 // set up proxy class access to proxy interfaces and types
822 // referenced in the method signature
823 Set<Class<?>> types = new HashSet<>(interfaces);
824 types.addAll(refTypes);
825 for (Class<?> c : types) {
826 ensureAccess(target, c);
827 }
828 return target;
829 }
830
831 /*
832 * Ensure the given module can access the given class.
833 */
834 private static void ensureAccess(Module target, Class<?> c) {
835 Module m = c.getModule();
836 // add read edge and qualified export for the target module to access
837 if (!target.canRead(m)) {
838 Modules.addReads(target, m);
839 }
840 String pn = c.getPackageName();
841 if (!m.isExported(pn, target)) {
842 Modules.addExports(m, pn, target);
843 }
844 }
845
846 /*
847 * Ensure the given class is visible to the class loader.
848 */
849 private static void ensureVisible(ClassLoader ld, Class<?> c) {
850 Class<?> type = null;
851 try {
852 type = Class.forName(c.getName(), false, ld);
853 } catch (ClassNotFoundException e) {
854 }
855 if (type != c) {
856 throw new IllegalArgumentException(c.getName() +
857 " referenced from a method is not visible from class loader");
858 }
859 }
860
861 private static Class<?> getElementType(Class<?> type) {
862 Class<?> e = type;
863 while (e.isArray()) {
864 e = e.getComponentType();
865 }
866 return e;
867 }
868
869 private static final ClassLoaderValue<Module> dynProxyModules =
870 new ClassLoaderValue<>();
871 private static final AtomicInteger counter = new AtomicInteger();
872
873 /*
874 * Define a dynamic module for the generated proxy classes in
875 * a non-exported package named com.sun.proxy.$MODULE.
876 *
877 * Each class loader will have one dynamic module.
878 */
879 private static Module getDynamicModule(ClassLoader loader) {
880 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
881 // create a dynamic module and setup module access
882 String mn = "jdk.proxy" + counter.incrementAndGet();
883 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
884 ModuleDescriptor descriptor =
885 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC))
886 .packages(Set.of(pn))
887 .build();
888 Module m = Modules.defineModule(ld, descriptor, null);
889 Modules.addReads(m, Proxy.class.getModule());
890 // java.base to create proxy instance
891 Modules.addExports(m, pn, Object.class.getModule());
892 return m;
893 });
894 }
895 }
896
897 /**
898 * Returns a proxy instance for the specified interfaces
899 * that dispatches method invocations to the specified invocation
900 * handler.
901 * <p>
902 * <a id="restrictions">{@code IllegalArgumentException} will be thrown
903 * if any of the following restrictions is violated:</a>
904 * <ul>
905 * <li>All of {@code Class} objects in the given {@code interfaces} array
906 * must represent interfaces, not classes or primitive types.
907 *
908 * <li>No two elements in the {@code interfaces} array may
909 * refer to identical {@code Class} objects.
910 *
911 * <li>All of the interface types must be visible by name through the
912 * specified class loader. In other words, for class loader
913 * {@code cl} and every interface {@code i}, the following
914 * expression must be true:<p>
915 * {@code Class.forName(i.getName(), false, cl) == i}
916 *
917 * <li>All of the types referenced by all
918 * public method signatures of the specified interfaces
919 * and those inherited by their superinterfaces
920 * must be visible by name through the specified class loader.
921 *
922 * <li>All non-public interfaces must be in the same package
923 * and module, defined by the specified class loader and
924 * the module of the non-public interfaces can access all of
925 * the interface types; otherwise, it would not be possible for
926 * the proxy class to implement all of the interfaces,
927 * regardless of what package it is defined in.
928 *
929 * <li>For any set of member methods of the specified interfaces
930 * that have the same signature:
931 * <ul>
932 * <li>If the return type of any of the methods is a primitive
933 * type or void, then all of the methods must have that same
934 * return type.
935 * <li>Otherwise, one of the methods must have a return type that
936 * is assignable to all of the return types of the rest of the
937 * methods.
938 * </ul>
939 *
940 * <li>The resulting proxy class must not exceed any limits imposed
941 * on classes by the virtual machine. For example, the VM may limit
942 * the number of interfaces that a class may implement to 65535; in
943 * that case, the size of the {@code interfaces} array must not
944 * exceed 65535.
945 * </ul>
946 *
947 * <p>Note that the order of the specified proxy interfaces is
948 * significant: two requests for a proxy class with the same combination
949 * of interfaces but in a different order will result in two distinct
950 * proxy classes.
951 *
952 * @param loader the class loader to define the proxy class
953 * @param interfaces the list of interfaces for the proxy class
954 * to implement
955 * @param h the invocation handler to dispatch method invocations to
956 * @return a proxy instance with the specified invocation handler of a
957 * proxy class that is defined by the specified class loader
958 * and that implements the specified interfaces
959 * @throws IllegalArgumentException if any of the <a href="#restrictions">
960 * restrictions</a> on the parameters are violated
961 * @throws SecurityException if a security manager, <em>s</em>, is present
962 * and any of the following conditions is met:
963 * <ul>
964 * <li> the given {@code loader} is {@code null} and
965 * the caller's class loader is not {@code null} and the
966 * invocation of {@link SecurityManager#checkPermission
967 * s.checkPermission} with
968 * {@code RuntimePermission("getClassLoader")} permission
969 * denies access;</li>
970 * <li> for each proxy interface, {@code intf},
971 * the caller's class loader is not the same as or an
972 * ancestor of the class loader for {@code intf} and
973 * invocation of {@link SecurityManager#checkPackageAccess
974 * s.checkPackageAccess()} denies access to {@code intf};</li>
975 * <li> any of the given proxy interfaces is non-public and the
976 * caller class is not in the same {@linkplain Package runtime package}
977 * as the non-public interface and the invocation of
978 * {@link SecurityManager#checkPermission s.checkPermission} with
979 * {@code ReflectPermission("newProxyInPackage.{package name}")}
980 * permission denies access.</li>
981 * </ul>
982 * @throws NullPointerException if the {@code interfaces} array
983 * argument or any of its elements are {@code null}, or
984 * if the invocation handler, {@code h}, is
985 * {@code null}
986 *
987 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
988 * @revised 9
989 * @spec JPMS
990 */
991 @CallerSensitive
992 public static Object newProxyInstance(ClassLoader loader,
993 Class<?>[] interfaces,
994 InvocationHandler h) {
995 Objects.requireNonNull(h);
996
997 final Class<?> caller = System.getSecurityManager() == null
998 ? null
999 : Reflection.getCallerClass();
1000
1001 /*
1002 * Look up or generate the designated proxy class and its constructor.
1003 */
1004 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
1005
1006 return newProxyInstance(caller, cons, h);
1007 }
1008
1009 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
1010 Constructor<?> cons,
1011 InvocationHandler h) {
1012 /*
1013 * Invoke its constructor with the designated invocation handler.
1014 */
1015 try {
1016 if (caller != null) {
1017 checkNewProxyPermission(caller, cons.getDeclaringClass());
1018 }
1019
1020 return cons.newInstance(new Object[]{h});
1021 } catch (IllegalAccessException | InstantiationException e) {
1022 throw new InternalError(e.toString(), e);
1023 } catch (InvocationTargetException e) {
1024 Throwable t = e.getCause();
1025 if (t instanceof RuntimeException) {
1026 throw (RuntimeException) t;
1027 } else {
1028 throw new InternalError(t.toString(), t);
1029 }
1030 }
1031 }
1032
1033 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1034 SecurityManager sm = System.getSecurityManager();
1035 if (sm != null) {
1036 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1037 ClassLoader ccl = caller.getClassLoader();
1038 ClassLoader pcl = proxyClass.getClassLoader();
1039
1040 // do permission check if the caller is in a different runtime package
1041 // of the proxy class
1042 String pkg = proxyClass.getPackageName();
1043 String callerPkg = caller.getPackageName();
1044
1045 if (pcl != ccl || !pkg.equals(callerPkg)) {
1046 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1047 }
1048 }
1049 }
1050 }
1051
1052 /**
1053 * Returns the class loader for the given module.
1054 */
1055 private static ClassLoader getLoader(Module m) {
1056 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1057 return AccessController.doPrivileged(pa);
1058 }
1059
1060 /**
1061 * Returns true if the given class is a proxy class.
1062 *
1063 * @implNote The reliability of this method is important for the ability
1064 * to use it to make security decisions, so its implementation should
1065 * not just test if the class in question extends {@code Proxy}.
1066 *
1067 * @param cl the class to test
1068 * @return {@code true} if the class is a proxy class and
1069 * {@code false} otherwise
1070 * @throws NullPointerException if {@code cl} is {@code null}
1071 *
1072 * @revised 9
1073 * @spec JPMS
1074 */
1075 public static boolean isProxyClass(Class<?> cl) {
1076 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1077 }
1078
1079 /**
1080 * Returns the invocation handler for the specified proxy instance.
1081 *
1082 * @param proxy the proxy instance to return the invocation handler for
1083 * @return the invocation handler for the proxy instance
1084 * @throws IllegalArgumentException if the argument is not a
1085 * proxy instance
1086 * @throws SecurityException if a security manager, <em>s</em>, is present
1087 * and the caller's class loader is not the same as or an
1088 * ancestor of the class loader for the invocation handler
1089 * and invocation of {@link SecurityManager#checkPackageAccess
1090 * s.checkPackageAccess()} denies access to the invocation
1091 * handler's class.
1092 */
1093 @CallerSensitive
1094 public static InvocationHandler getInvocationHandler(Object proxy)
1095 throws IllegalArgumentException
1096 {
1097 /*
1098 * Verify that the object is actually a proxy instance.
1099 */
1100 if (!isProxyClass(proxy.getClass())) {
1101 throw new IllegalArgumentException("not a proxy instance");
1102 }
1103
1104 final Proxy p = (Proxy) proxy;
1105 final InvocationHandler ih = p.h;
1106 if (System.getSecurityManager() != null) {
1107 Class<?> ihClass = ih.getClass();
1108 Class<?> caller = Reflection.getCallerClass();
1109 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1110 ihClass.getClassLoader()))
1111 {
1112 ReflectUtil.checkPackageAccess(ihClass);
1113 }
1114 }
1115
1116 return ih;
1117 }
1118
1119 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
1120 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1121 }