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 @java.io.Serial
287 private static final long serialVersionUID = -2222568056686623797L;
288
289 /** parameter types of a proxy class constructor */
290 private static final Class<?>[] constructorParams =
291 { InvocationHandler.class };
292
293 /**
294 * a cache of proxy constructors with
295 * {@link Constructor#setAccessible(boolean) accessible} flag already set
296 */
297 private static final ClassLoaderValue<Constructor<?>> proxyCache =
298 new ClassLoaderValue<>();
299
300 /**
301 * System property to revert to generation of proxy class files for version 1.5 (V49).
302 * Set to "true" to generate v49 class file format.
303 */
304 private static final boolean PROXY_GENERATOR_V49 =
305 GetBooleanAction.privilegedGetProperty("jdk.proxy.ProxyGenerator.v49");
306
307 /**
308 * the invocation handler for this proxy instance.
309 * @serial
310 */
311 protected InvocationHandler h;
312
313 /**
314 * Prohibits instantiation.
315 */
316 private Proxy() {
317 }
318
319 /**
320 * Constructs a new {@code Proxy} instance from a subclass
321 * (typically, a dynamic proxy class) with the specified value
322 * for its invocation handler.
323 *
324 * @param h the invocation handler for this proxy instance
325 *
326 * @throws NullPointerException if the given invocation handler, {@code h},
327 * is {@code null}.
328 */
329 protected Proxy(InvocationHandler h) {
330 Objects.requireNonNull(h);
331 this.h = h;
332 }
333
334 /**
335 * Returns the {@code java.lang.Class} object for a proxy class
336 * given a class loader and an array of interfaces. The proxy class
337 * will be defined by the specified class loader and will implement
338 * all of the supplied interfaces. If any of the given interfaces
339 * is non-public, the proxy class will be non-public. If a proxy class
340 * for the same permutation of interfaces has already been defined by the
341 * class loader, then the existing proxy class will be returned; otherwise,
342 * a proxy class for those interfaces will be generated dynamically
343 * and defined by the class loader.
344 *
345 * @param loader the class loader to define the proxy class
346 * @param interfaces the list of interfaces for the proxy class
347 * to implement
348 * @return a proxy class that is defined in the specified class loader
349 * and that implements the specified interfaces
350 * @throws IllegalArgumentException if any of the <a href="#restrictions">
351 * restrictions</a> on the parameters are violated
352 * @throws SecurityException if a security manager, <em>s</em>, is present
353 * and any of the following conditions is met:
354 * <ul>
355 * <li> the given {@code loader} is {@code null} and
356 * the caller's class loader is not {@code null} and the
357 * invocation of {@link SecurityManager#checkPermission
358 * s.checkPermission} with
359 * {@code RuntimePermission("getClassLoader")} permission
360 * denies access.</li>
361 * <li> for each proxy interface, {@code intf},
362 * the caller's class loader is not the same as or an
363 * ancestor of the class loader for {@code intf} and
364 * invocation of {@link SecurityManager#checkPackageAccess
365 * s.checkPackageAccess()} denies access to {@code intf}.</li>
366 * </ul>
367 * @throws NullPointerException if the {@code interfaces} array
368 * argument or any of its elements are {@code null}
369 *
370 * @deprecated Proxy classes generated in a named module are encapsulated
371 * and not accessible to code outside its module.
372 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
373 * will throw {@code IllegalAccessException} when it is called on
374 * an inaccessible proxy class.
375 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
376 * to create a proxy instance instead.
377 *
378 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
379 * @revised 9
380 * @spec JPMS
381 */
382 @Deprecated
383 @CallerSensitive
384 public static Class<?> getProxyClass(ClassLoader loader,
385 Class<?>... interfaces)
386 throws IllegalArgumentException
387 {
388 Class<?> caller = System.getSecurityManager() == null
389 ? null
390 : Reflection.getCallerClass();
391
392 return getProxyConstructor(caller, loader, interfaces)
393 .getDeclaringClass();
394 }
395
396 /**
397 * Returns the {@code Constructor} object of a proxy class that takes a
398 * single argument of type {@link InvocationHandler}, given a class loader
399 * and an array of interfaces. The returned constructor will have the
400 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
401 *
402 * @param caller passed from a public-facing @CallerSensitive method if
403 * SecurityManager is set or {@code null} if there's no
404 * SecurityManager
405 * @param loader the class loader to define the proxy class
406 * @param interfaces the list of interfaces for the proxy class
407 * to implement
408 * @return a Constructor of the proxy class taking single
409 * {@code InvocationHandler} parameter
410 */
411 private static Constructor<?> getProxyConstructor(Class<?> caller,
412 ClassLoader loader,
413 Class<?>... interfaces)
414 {
415 // optimization for single interface
416 if (interfaces.length == 1) {
417 Class<?> intf = interfaces[0];
418 if (caller != null) {
419 checkProxyAccess(caller, loader, intf);
420 }
421 return proxyCache.sub(intf).computeIfAbsent(
422 loader,
423 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
424 );
425 } else {
426 // interfaces cloned
427 final Class<?>[] intfsArray = interfaces.clone();
428 if (caller != null) {
429 checkProxyAccess(caller, loader, intfsArray);
430 }
431 final List<Class<?>> intfs = Arrays.asList(intfsArray);
432 return proxyCache.sub(intfs).computeIfAbsent(
433 loader,
434 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
435 );
436 }
437 }
438
439 /*
440 * Check permissions required to create a Proxy class.
441 *
442 * To define a proxy class, it performs the access checks as in
443 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
444 * 1. "getClassLoader" permission check if loader == null
445 * 2. checkPackageAccess on the interfaces it implements
446 *
447 * To get a constructor and new instance of a proxy class, it performs
448 * the package access check on the interfaces it implements
449 * as in Class.getConstructor.
450 *
451 * If an interface is non-public, the proxy class must be defined by
452 * the defining loader of the interface. If the caller's class loader
453 * is not the same as the defining loader of the interface, the VM
454 * will throw IllegalAccessError when the generated proxy class is
455 * being defined.
456 */
457 private static void checkProxyAccess(Class<?> caller,
458 ClassLoader loader,
459 Class<?> ... interfaces)
460 {
461 SecurityManager sm = System.getSecurityManager();
462 if (sm != null) {
463 ClassLoader ccl = caller.getClassLoader();
464 if (loader == null && ccl != null) {
465 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
466 }
467 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
468 }
469 }
470
471 /**
472 * Builder for a proxy class.
473 *
474 * If the module is not specified in this ProxyBuilder constructor,
475 * it will map from the given loader and interfaces to the module
476 * in which the proxy class will be defined.
477 */
478 private static final class ProxyBuilder {
479 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
480
481 // prefix for all proxy class names
482 private static final String proxyClassNamePrefix = "$Proxy";
483
484 // next number to use for generation of unique proxy class names
485 private static final AtomicLong nextUniqueNumber = new AtomicLong();
486
487 // a reverse cache of defined proxy classes
488 private static final ClassLoaderValue<Boolean> reverseProxyCache =
489 new ClassLoaderValue<>();
490
491 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) {
492 String proxyPkg = null; // package to define proxy class in
493 int accessFlags = Modifier.PUBLIC | Modifier.FINAL;
494
495 /*
496 * Record the package of a non-public proxy interface so that the
497 * proxy class will be defined in the same package. Verify that
498 * all non-public proxy interfaces are in the same package.
499 */
500 for (Class<?> intf : interfaces) {
501 int flags = intf.getModifiers();
502 if (!Modifier.isPublic(flags)) {
503 accessFlags = Modifier.FINAL; // non-public, final
504 String pkg = intf.getPackageName();
505 if (proxyPkg == null) {
506 proxyPkg = pkg;
507 } else if (!pkg.equals(proxyPkg)) {
508 throw new IllegalArgumentException(
509 "non-public interfaces from different packages");
510 }
511 }
512 }
513
514 if (proxyPkg == null) {
515 // all proxy interfaces are public
516 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName()
517 : PROXY_PACKAGE_PREFIX;
518 } else if (proxyPkg.isEmpty() && m.isNamed()) {
519 throw new IllegalArgumentException(
520 "Unnamed package cannot be added to " + m);
521 }
522
523 if (m.isNamed()) {
524 if (!m.getDescriptor().packages().contains(proxyPkg)) {
525 throw new InternalError(proxyPkg + " not exist in " + m.getName());
526 }
527 }
528
529 /*
530 * Choose a name for the proxy class to generate.
531 */
532 long num = nextUniqueNumber.getAndIncrement();
533 String proxyName = proxyPkg.isEmpty()
534 ? proxyClassNamePrefix + num
535 : proxyPkg + "." + proxyClassNamePrefix + num;
536
537 ClassLoader loader = getLoader(m);
538 trace(proxyName, m, loader, interfaces);
539
540 /*
541 * Generate the specified proxy class.
542 */
543 byte[] proxyClassFile = PROXY_GENERATOR_V49
544 ? ProxyGenerator_v49.generateProxyClass(proxyName, interfaces, accessFlags)
545 : ProxyGenerator.generateProxyClass(loader, proxyName, interfaces, accessFlags);
546 try {
547 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
548 null, "__dynamic_proxy__");
549 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
550 return pc;
551 } catch (ClassFormatError e) {
552 /*
553 * A ClassFormatError here means that (barring bugs in the
554 * proxy class generation code) there was some other
555 * invalid aspect of the arguments supplied to the proxy
556 * class creation (such as virtual machine limitations
557 * exceeded).
558 */
559 throw new IllegalArgumentException(e.toString());
560 }
561 }
562
563 /**
564 * Test if given class is a class defined by
565 * {@link #defineProxyClass(Module, List)}
566 */
567 static boolean isProxyClass(Class<?> c) {
568 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
569 Boolean.TRUE);
570 }
571
572 private static boolean isExportedType(Class<?> c) {
573 String pn = c.getPackageName();
574 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
575 }
576
577 private static boolean isPackagePrivateType(Class<?> c) {
578 return !Modifier.isPublic(c.getModifiers());
579 }
580
581 private static String toDetails(Class<?> c) {
582 String access = "unknown";
583 if (isExportedType(c)) {
584 access = "exported";
585 } else if (isPackagePrivateType(c)) {
586 access = "package-private";
587 } else {
588 access = "module-private";
589 }
590 ClassLoader ld = c.getClassLoader();
591 return String.format(" %s/%s %s loader %s",
592 c.getModule().getName(), c.getName(), access, ld);
593 }
594
595 static void trace(String cn,
596 Module module,
597 ClassLoader loader,
598 List<Class<?>> interfaces) {
599 if (isDebug()) {
600 System.err.format("PROXY: %s/%s defined by %s%n",
601 module.getName(), cn, loader);
602 }
603 if (isDebug("debug")) {
604 interfaces.forEach(c -> System.out.println(toDetails(c)));
605 }
606 }
607
608 private static final String DEBUG =
609 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
610
611 private static boolean isDebug() {
612 return !DEBUG.isEmpty();
613 }
614 private static boolean isDebug(String flag) {
615 return DEBUG.equals(flag);
616 }
617
618 // ProxyBuilder instance members start here....
619
620 private final List<Class<?>> interfaces;
621 private final Module module;
622 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
623 if (!VM.isModuleSystemInited()) {
624 throw new InternalError("Proxy is not supported until "
625 + "module system is fully initialized");
626 }
627 if (interfaces.size() > 65535) {
628 throw new IllegalArgumentException("interface limit exceeded: "
629 + interfaces.size());
630 }
631
632 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
633
634 // IAE if violates any restrictions specified in newProxyInstance
635 validateProxyInterfaces(loader, interfaces, refTypes);
636
637 this.interfaces = interfaces;
638 this.module = mapToModule(loader, interfaces, refTypes);
639 assert getLoader(module) == loader;
640 }
641
642 ProxyBuilder(ClassLoader loader, Class<?> intf) {
643 this(loader, Collections.singletonList(intf));
644 }
645
646 /**
647 * Generate a proxy class and return its proxy Constructor with
648 * accessible flag already set. If the target module does not have access
649 * to any interface types, IllegalAccessError will be thrown by the VM
650 * at defineClass time.
651 *
652 * Must call the checkProxyAccess method to perform permission checks
653 * before calling this.
654 */
655 Constructor<?> build() {
656 Class<?> proxyClass = defineProxyClass(module, interfaces);
657 final Constructor<?> cons;
658 try {
659 cons = proxyClass.getConstructor(constructorParams);
660 } catch (NoSuchMethodException e) {
661 throw new InternalError(e.toString(), e);
662 }
663 AccessController.doPrivileged(new PrivilegedAction<Void>() {
664 public Void run() {
665 cons.setAccessible(true);
666 return null;
667 }
668 });
669 return cons;
670 }
671
672 /**
673 * Validate the given proxy interfaces and the given referenced types
674 * are visible to the defining loader.
675 *
676 * @throws IllegalArgumentException if it violates the restrictions
677 * specified in {@link Proxy#newProxyInstance}
678 */
679 private static void validateProxyInterfaces(ClassLoader loader,
680 List<Class<?>> interfaces,
681 Set<Class<?>> refTypes)
682 {
683 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
684 for (Class<?> intf : interfaces) {
685 /*
686 * Verify that the class loader resolves the name of this
687 * interface to the same Class object.
688 */
689 ensureVisible(loader, intf);
690
691 /*
692 * Verify that the Class object actually represents an
693 * interface.
694 */
695 if (!intf.isInterface()) {
696 throw new IllegalArgumentException(intf.getName() + " is not an interface");
697 }
698
699 /*
700 * Verify that this interface is not a duplicate.
701 */
702 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
703 throw new IllegalArgumentException("repeated interface: " + intf.getName());
704 }
705 }
706
707 for (Class<?> type : refTypes) {
708 ensureVisible(loader, type);
709 }
710 }
711
712 /*
713 * Returns all types referenced by all public non-static method signatures of
714 * the proxy interfaces
715 */
716 private static Set<Class<?>> referencedTypes(ClassLoader loader,
717 List<Class<?>> interfaces) {
718 var types = new HashSet<Class<?>>();
719 for (var intf : interfaces) {
720 for (Method m : intf.getMethods()) {
721 if (!Modifier.isStatic(m.getModifiers())) {
722 addElementType(types, m.getReturnType());
723 addElementTypes(types, m.getSharedParameterTypes());
724 addElementTypes(types, m.getSharedExceptionTypes());
725 }
726 }
727 }
728 return types;
729 }
730
731 private static void addElementTypes(HashSet<Class<?>> types,
732 Class<?> ... classes) {
733 for (var cls : classes) {
734 addElementType(types, cls);
735 }
736 }
737
738 private static void addElementType(HashSet<Class<?>> types,
739 Class<?> cls) {
740 var type = getElementType(cls);
741 if (!type.isPrimitive()) {
742 types.add(type);
743 }
744 }
745
746 /**
747 * Returns the module that the generated proxy class belongs to.
748 *
749 * If all proxy interfaces are public and in exported packages,
750 * then the proxy class is in unnamed module.
751 *
752 * If any of proxy interface is package-private, then the proxy class
753 * is in the same module of the package-private interface.
754 *
755 * If all proxy interfaces are public and at least one in a non-exported
756 * package, then the proxy class is in a dynamic module in a
757 * non-exported package. Reads edge and qualified exports are added
758 * for dynamic module to access.
759 */
760 private static Module mapToModule(ClassLoader loader,
761 List<Class<?>> interfaces,
762 Set<Class<?>> refTypes) {
763 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>();
764 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
765 for (Class<?> intf : interfaces) {
766 Module m = intf.getModule();
767 if (Modifier.isPublic(intf.getModifiers())) {
768 // module-private types
769 if (!m.isExported(intf.getPackageName())) {
770 modulePrivateTypes.put(intf, m);
771 }
772 } else {
773 packagePrivateTypes.put(intf, m);
774 }
775 }
776
777 // all proxy interfaces are public and exported, the proxy class
778 // is in unnamed module. Such proxy class is accessible to
779 // any unnamed module and named module that can read unnamed module
780 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) {
781 return loader != null ? loader.getUnnamedModule()
782 : BootLoader.getUnnamedModule();
783 }
784
785 if (packagePrivateTypes.size() > 0) {
786 // all package-private types must be in the same runtime package
787 // i.e. same package name and same module (named or unnamed)
788 //
789 // Configuration will fail if M1 and in M2 defined by the same loader
790 // and both have the same package p (so no need to check class loader)
791 if (packagePrivateTypes.size() > 1 &&
792 (packagePrivateTypes.keySet().stream() // more than one package
793 .map(Class::getPackageName).distinct().count() > 1 ||
794 packagePrivateTypes.values().stream() // or more than one module
795 .distinct().count() > 1)) {
796 throw new IllegalArgumentException(
797 "non-public interfaces from different packages");
798 }
799
800 // all package-private types are in the same module (named or unnamed)
801 Module target = null;
802 for (Module m : packagePrivateTypes.values()) {
803 if (getLoader(m) != loader) {
804 // the specified loader is not the same class loader
805 // of the non-public interface
806 throw new IllegalArgumentException(
807 "non-public interface is not defined by the given loader");
808 }
809 target = m;
810 }
811
812 // validate if the target module can access all other interfaces
813 for (Class<?> intf : interfaces) {
814 Module m = intf.getModule();
815 if (m == target) continue;
816
817 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) {
818 throw new IllegalArgumentException(target + " can't access " + intf.getName());
819 }
820 }
821
822 // return the module of the package-private interface
823 return target;
824 }
825
826 // All proxy interfaces are public and at least one in a non-exported
827 // package. So maps to a dynamic proxy module and add reads edge
828 // and qualified exports, if necessary
829 Module target = getDynamicModule(loader);
830
831 // set up proxy class access to proxy interfaces and types
832 // referenced in the method signature
833 Set<Class<?>> types = new HashSet<>(interfaces);
834 types.addAll(refTypes);
835 for (Class<?> c : types) {
836 ensureAccess(target, c);
837 }
838 return target;
839 }
840
841 /*
842 * Ensure the given module can access the given class.
843 */
844 private static void ensureAccess(Module target, Class<?> c) {
845 Module m = c.getModule();
846 // add read edge and qualified export for the target module to access
847 if (!target.canRead(m)) {
848 Modules.addReads(target, m);
849 }
850 String pn = c.getPackageName();
851 if (!m.isExported(pn, target)) {
852 Modules.addExports(m, pn, target);
853 }
854 }
855
856 /*
857 * Ensure the given class is visible to the class loader.
858 */
859 private static void ensureVisible(ClassLoader ld, Class<?> c) {
860 Class<?> type = null;
861 try {
862 type = Class.forName(c.getName(), false, ld);
863 } catch (ClassNotFoundException e) {
864 }
865 if (type != c) {
866 throw new IllegalArgumentException(c.getName() +
867 " referenced from a method is not visible from class loader");
868 }
869 }
870
871 private static Class<?> getElementType(Class<?> type) {
872 Class<?> e = type;
873 while (e.isArray()) {
874 e = e.getComponentType();
875 }
876 return e;
877 }
878
879 private static final ClassLoaderValue<Module> dynProxyModules =
880 new ClassLoaderValue<>();
881 private static final AtomicInteger counter = new AtomicInteger();
882
883 /*
884 * Define a dynamic module for the generated proxy classes in
885 * a non-exported package named com.sun.proxy.$MODULE.
886 *
887 * Each class loader will have one dynamic module.
888 */
889 private static Module getDynamicModule(ClassLoader loader) {
890 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
891 // create a dynamic module and setup module access
892 String mn = "jdk.proxy" + counter.incrementAndGet();
893 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
894 ModuleDescriptor descriptor =
895 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC))
896 .packages(Set.of(pn))
897 .build();
898 Module m = Modules.defineModule(ld, descriptor, null);
899 Modules.addReads(m, Proxy.class.getModule());
900 // java.base to create proxy instance
901 Modules.addExports(m, pn, Object.class.getModule());
902 return m;
903 });
904 }
905 }
906
907 /**
908 * Returns a proxy instance for the specified interfaces
909 * that dispatches method invocations to the specified invocation
910 * handler.
911 * <p>
912 * <a id="restrictions">{@code IllegalArgumentException} will be thrown
913 * if any of the following restrictions is violated:</a>
914 * <ul>
915 * <li>All of {@code Class} objects in the given {@code interfaces} array
916 * must represent interfaces, not classes or primitive types.
917 *
918 * <li>No two elements in the {@code interfaces} array may
919 * refer to identical {@code Class} objects.
920 *
921 * <li>All of the interface types must be visible by name through the
922 * specified class loader. In other words, for class loader
923 * {@code cl} and every interface {@code i}, the following
924 * expression must be true:<p>
925 * {@code Class.forName(i.getName(), false, cl) == i}
926 *
927 * <li>All of the types referenced by all
928 * public method signatures of the specified interfaces
929 * and those inherited by their superinterfaces
930 * must be visible by name through the specified class loader.
931 *
932 * <li>All non-public interfaces must be in the same package
933 * and module, defined by the specified class loader and
934 * the module of the non-public interfaces can access all of
935 * the interface types; otherwise, it would not be possible for
936 * the proxy class to implement all of the interfaces,
937 * regardless of what package it is defined in.
938 *
939 * <li>For any set of member methods of the specified interfaces
940 * that have the same signature:
941 * <ul>
942 * <li>If the return type of any of the methods is a primitive
943 * type or void, then all of the methods must have that same
944 * return type.
945 * <li>Otherwise, one of the methods must have a return type that
946 * is assignable to all of the return types of the rest of the
947 * methods.
948 * </ul>
949 *
950 * <li>The resulting proxy class must not exceed any limits imposed
951 * on classes by the virtual machine. For example, the VM may limit
952 * the number of interfaces that a class may implement to 65535; in
953 * that case, the size of the {@code interfaces} array must not
954 * exceed 65535.
955 * </ul>
956 *
957 * <p>Note that the order of the specified proxy interfaces is
958 * significant: two requests for a proxy class with the same combination
959 * of interfaces but in a different order will result in two distinct
960 * proxy classes.
961 *
962 * @param loader the class loader to define the proxy class
963 * @param interfaces the list of interfaces for the proxy class
964 * to implement
965 * @param h the invocation handler to dispatch method invocations to
966 * @return a proxy instance with the specified invocation handler of a
967 * proxy class that is defined by the specified class loader
968 * and that implements the specified interfaces
969 * @throws IllegalArgumentException if any of the <a href="#restrictions">
970 * restrictions</a> on the parameters are violated
971 * @throws SecurityException if a security manager, <em>s</em>, is present
972 * and any of the following conditions is met:
973 * <ul>
974 * <li> the given {@code loader} is {@code null} and
975 * the caller's class loader is not {@code null} and the
976 * invocation of {@link SecurityManager#checkPermission
977 * s.checkPermission} with
978 * {@code RuntimePermission("getClassLoader")} permission
979 * denies access;</li>
980 * <li> for each proxy interface, {@code intf},
981 * the caller's class loader is not the same as or an
982 * ancestor of the class loader for {@code intf} and
983 * invocation of {@link SecurityManager#checkPackageAccess
984 * s.checkPackageAccess()} denies access to {@code intf};</li>
985 * <li> any of the given proxy interfaces is non-public and the
986 * caller class is not in the same {@linkplain Package runtime package}
987 * as the non-public interface and the invocation of
988 * {@link SecurityManager#checkPermission s.checkPermission} with
989 * {@code ReflectPermission("newProxyInPackage.{package name}")}
990 * permission denies access.</li>
991 * </ul>
992 * @throws NullPointerException if the {@code interfaces} array
993 * argument or any of its elements are {@code null}, or
994 * if the invocation handler, {@code h}, is
995 * {@code null}
996 *
997 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
998 * @revised 9
999 * @spec JPMS
1000 */
1001 @CallerSensitive
1002 public static Object newProxyInstance(ClassLoader loader,
1003 Class<?>[] interfaces,
1004 InvocationHandler h) {
1005 Objects.requireNonNull(h);
1006
1007 final Class<?> caller = System.getSecurityManager() == null
1008 ? null
1009 : Reflection.getCallerClass();
1010
1011 /*
1012 * Look up or generate the designated proxy class and its constructor.
1013 */
1014 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
1015
1016 return newProxyInstance(caller, cons, h);
1017 }
1018
1019 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
1020 Constructor<?> cons,
1021 InvocationHandler h) {
1022 /*
1023 * Invoke its constructor with the designated invocation handler.
1024 */
1025 try {
1026 if (caller != null) {
1027 checkNewProxyPermission(caller, cons.getDeclaringClass());
1028 }
1029
1030 return cons.newInstance(new Object[]{h});
1031 } catch (IllegalAccessException | InstantiationException e) {
1032 throw new InternalError(e.toString(), e);
1033 } catch (InvocationTargetException e) {
1034 Throwable t = e.getCause();
1035 if (t instanceof RuntimeException) {
1036 throw (RuntimeException) t;
1037 } else {
1038 throw new InternalError(t.toString(), t);
1039 }
1040 }
1041 }
1042
1043 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1044 SecurityManager sm = System.getSecurityManager();
1045 if (sm != null) {
1046 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1047 ClassLoader ccl = caller.getClassLoader();
1048 ClassLoader pcl = proxyClass.getClassLoader();
1049
1050 // do permission check if the caller is in a different runtime package
1051 // of the proxy class
1052 String pkg = proxyClass.getPackageName();
1053 String callerPkg = caller.getPackageName();
1054
1055 if (pcl != ccl || !pkg.equals(callerPkg)) {
1056 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1057 }
1058 }
1059 }
1060 }
1061
1062 /**
1063 * Returns the class loader for the given module.
1064 */
1065 private static ClassLoader getLoader(Module m) {
1066 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1067 return AccessController.doPrivileged(pa);
1068 }
1069
1070 /**
1071 * Returns true if the given class is a proxy class.
1072 *
1073 * @implNote The reliability of this method is important for the ability
1074 * to use it to make security decisions, so its implementation should
1075 * not just test if the class in question extends {@code Proxy}.
1076 *
1077 * @param cl the class to test
1078 * @return {@code true} if the class is a proxy class and
1079 * {@code false} otherwise
1080 * @throws NullPointerException if {@code cl} is {@code null}
1081 *
1082 * @revised 9
1083 * @spec JPMS
1084 */
1085 public static boolean isProxyClass(Class<?> cl) {
1086 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1087 }
1088
1089 /**
1090 * Returns the invocation handler for the specified proxy instance.
1091 *
1092 * @param proxy the proxy instance to return the invocation handler for
1093 * @return the invocation handler for the proxy instance
1094 * @throws IllegalArgumentException if the argument is not a
1095 * proxy instance
1096 * @throws SecurityException if a security manager, <em>s</em>, is present
1097 * and the caller's class loader is not the same as or an
1098 * ancestor of the class loader for the invocation handler
1099 * and invocation of {@link SecurityManager#checkPackageAccess
1100 * s.checkPackageAccess()} denies access to the invocation
1101 * handler's class.
1102 */
1103 @CallerSensitive
1104 public static InvocationHandler getInvocationHandler(Object proxy)
1105 throws IllegalArgumentException
1106 {
1107 /*
1108 * Verify that the object is actually a proxy instance.
1109 */
1110 if (!isProxyClass(proxy.getClass())) {
1111 throw new IllegalArgumentException("not a proxy instance");
1112 }
1113
1114 final Proxy p = (Proxy) proxy;
1115 final InvocationHandler ih = p.h;
1116 if (System.getSecurityManager() != null) {
1117 Class<?> ihClass = ih.getClass();
1118 Class<?> caller = Reflection.getCallerClass();
1119 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1120 ihClass.getClassLoader()))
1121 {
1122 ReflectUtil.checkPackageAccess(ihClass);
1123 }
1124 }
1125
1126 return ih;
1127 }
1128
1129 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1130 }