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