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.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 import java.util.stream.Collectors; 43 import java.util.stream.Stream; 44 45 import jdk.internal.loader.BootLoader; 46 import jdk.internal.module.Modules; 47 import jdk.internal.misc.Unsafe; 48 import jdk.internal.misc.VM; 49 import jdk.internal.reflect.CallerSensitive; 50 import jdk.internal.reflect.Reflection; 51 import jdk.internal.loader.ClassLoaderValue; 52 import sun.reflect.misc.ReflectUtil; 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 * <h3><a name="membership">Package and Module Membership of Proxy Class</a></h3> 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 name="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 class 231 * 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 java.lang.reflect.Module module} 234 * of {@code T} is updated to export the package of {@code T} to the dynamic module. 235 * 236 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3> 237 * 238 * <p>When two or more proxy interfaces contain a method with 239 * the same name and parameter signature, the order of the proxy class's 240 * interfaces becomes significant. When such a <i>duplicate method</i> 241 * is invoked on a proxy instance, the {@code Method} object passed 242 * to the invocation handler will not necessarily be the one whose 243 * declaring class is assignable from the reference type of the interface 244 * that the proxy's method was invoked through. This limitation exists 245 * because the corresponding method implementation in the generated proxy 246 * class cannot determine which interface it was invoked through. 247 * Therefore, when a duplicate method is invoked on a proxy instance, 248 * the {@code Method} object for the method in the foremost interface 249 * that contains the method (either directly or inherited through a 250 * superinterface) in the proxy class's list of interfaces is passed to 251 * the invocation handler's {@code invoke} method, regardless of the 252 * reference type through which the method invocation occurred. 253 * 254 * <p>If a proxy interface contains a method with the same name and 255 * parameter signature as the {@code hashCode}, {@code equals}, 256 * or {@code toString} methods of {@code java.lang.Object}, 257 * when such a method is invoked on a proxy instance, the 258 * {@code Method} object passed to the invocation handler will have 259 * {@code java.lang.Object} as its declaring class. In other words, 260 * the public, non-final methods of {@code java.lang.Object} 261 * logically precede all of the proxy interfaces for the determination of 262 * which {@code Method} object to pass to the invocation handler. 263 * 264 * <p>Note also that when a duplicate method is dispatched to an 265 * invocation handler, the {@code invoke} method may only throw 266 * checked exception types that are assignable to one of the exception 267 * types in the {@code throws} clause of the method in <i>all</i> of 268 * the proxy interfaces that it can be invoked through. If the 269 * {@code invoke} method throws a checked exception that is not 270 * assignable to any of the exception types declared by the method in one 271 * of the proxy interfaces that it can be invoked through, then an 272 * unchecked {@code UndeclaredThrowableException} will be thrown by 273 * the invocation on the proxy instance. This restriction means that not 274 * all of the exception types returned by invoking 275 * {@code getExceptionTypes} on the {@code Method} object 276 * passed to the {@code invoke} method can necessarily be thrown 277 * successfully by the {@code invoke} method. 278 * 279 * @author Peter Jones 280 * @see InvocationHandler 281 * @since 1.3 282 * @revised 9 283 * @spec JPMS 284 */ 285 public class Proxy implements java.io.Serializable { 286 private static final long serialVersionUID = -2222568056686623797L; 287 288 /** parameter types of a proxy class constructor */ 289 private static final Class<?>[] constructorParams = 290 { InvocationHandler.class }; 291 292 /** 293 * a cache of proxy constructors with 294 * {@link Constructor#setAccessible(boolean) accessible} flag already set 295 */ 296 private static final ClassLoaderValue<Constructor<?>> proxyCache = 297 new ClassLoaderValue<>(); 298 299 /** 300 * the invocation handler for this proxy instance. 301 * @serial 302 */ 303 protected InvocationHandler h; 304 305 /** 306 * Prohibits instantiation. 307 */ 308 private Proxy() { 309 } 310 311 /** 312 * Constructs a new {@code Proxy} instance from a subclass 313 * (typically, a dynamic proxy class) with the specified value 314 * for its invocation handler. 315 * 316 * @param h the invocation handler for this proxy instance 317 * 318 * @throws NullPointerException if the given invocation handler, {@code h}, 319 * is {@code null}. 320 */ 321 protected Proxy(InvocationHandler h) { 322 Objects.requireNonNull(h); 323 this.h = h; 324 } 325 326 /** 327 * Returns the {@code java.lang.Class} object for a proxy class 328 * given a class loader and an array of interfaces. The proxy class 329 * will be defined by the specified class loader and will implement 330 * all of the supplied interfaces. If any of the given interfaces 331 * is non-public, the proxy class will be non-public. If a proxy class 332 * for the same permutation of interfaces has already been defined by the 333 * class loader, then the existing proxy class will be returned; otherwise, 334 * a proxy class for those interfaces will be generated dynamically 335 * and defined by the class loader. 336 * 337 * @param loader the class loader to define the proxy class 338 * @param interfaces the list of interfaces for the proxy class 339 * to implement 340 * @return a proxy class that is defined in the specified class loader 341 * and that implements the specified interfaces 342 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 343 * restrictions</a> on the parameters are violated 344 * @throws SecurityException if a security manager, <em>s</em>, is present 345 * and any of the following conditions is met: 346 * <ul> 347 * <li> the given {@code loader} is {@code null} and 348 * the caller's class loader is not {@code null} and the 349 * invocation of {@link SecurityManager#checkPermission 350 * s.checkPermission} with 351 * {@code RuntimePermission("getClassLoader")} permission 352 * denies access.</li> 353 * <li> for each proxy interface, {@code intf}, 354 * the caller's class loader is not the same as or an 355 * ancestor of the class loader for {@code intf} and 356 * invocation of {@link SecurityManager#checkPackageAccess 357 * s.checkPackageAccess()} denies access to {@code intf}.</li> 358 * </ul> 359 * @throws NullPointerException if the {@code interfaces} array 360 * argument or any of its elements are {@code null} 361 * 362 * @deprecated Proxy classes generated in a named module are encapsulated and not 363 * accessible to code outside its module. 364 * {@link Constructor#newInstance(Object...) Constructor.newInstance} will throw 365 * {@code IllegalAccessException} when it is called on 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 (VM.isSystemDomainLoader(loader) && !VM.isSystemDomainLoader(ccl)) { 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 Unsafe UNSAFE = Unsafe.getUnsafe(); 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 // add the package to the runtime module if not exists 515 if (m.isNamed()) { 516 m.addPackage(proxyPkg); 517 } 518 519 /* 520 * Choose a name for the proxy class to generate. 521 */ 522 long num = nextUniqueNumber.getAndIncrement(); 523 String proxyName = proxyPkg.isEmpty() ? proxyClassNamePrefix + num 524 : proxyPkg + "." + proxyClassNamePrefix + num; 525 526 ClassLoader loader = getLoader(m); 527 trace(proxyName, m, loader, interfaces); 528 529 /* 530 * Generate the specified proxy class. 531 */ 532 byte[] proxyClassFile = ProxyGenerator.generateProxyClass( 533 proxyName, interfaces.toArray(EMPTY_CLASS_ARRAY), accessFlags); 534 try { 535 Class<?> pc = UNSAFE.defineClass(proxyName, proxyClassFile, 536 0, proxyClassFile.length, 537 loader, null); 538 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE); 539 return pc; 540 } catch (ClassFormatError e) { 541 /* 542 * A ClassFormatError here means that (barring bugs in the 543 * proxy class generation code) there was some other 544 * invalid aspect of the arguments supplied to the proxy 545 * class creation (such as virtual machine limitations 546 * exceeded). 547 */ 548 throw new IllegalArgumentException(e.toString()); 549 } 550 } 551 552 /** 553 * Test if given class is a class defined by 554 * {@link #defineProxyClass(Module, List)} 555 */ 556 static boolean isProxyClass(Class<?> c) { 557 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()), 558 Boolean.TRUE); 559 } 560 561 private static boolean isExportedType(Class<?> c) { 562 String pn = c.getPackageName(); 563 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn); 564 } 565 566 private static boolean isPackagePrivateType(Class<?> c) { 567 return !Modifier.isPublic(c.getModifiers()); 568 } 569 570 private static String toDetails(Class<?> c) { 571 String access = "unknown"; 572 if (isExportedType(c)) { 573 access = "exported"; 574 } else if (isPackagePrivateType(c)) { 575 access = "package-private"; 576 } else { 577 access = "module-private"; 578 } 579 ClassLoader ld = c.getClassLoader(); 580 return String.format(" %s/%s %s loader %s", 581 c.getModule().getName(), c.getName(), access, ld); 582 } 583 584 static void trace(String cn, Module module, ClassLoader loader, List<Class<?>> interfaces) { 585 if (isDebug()) { 586 System.out.format("PROXY: %s/%s defined by %s%n", module.getName(), cn, loader); 587 } 588 if (isDebug("debug")) { 589 interfaces.stream() 590 .forEach(c -> System.out.println(toDetails(c))); 591 } 592 } 593 594 private static final String DEBUG = 595 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", ""); 596 597 private static boolean isDebug() { 598 return !DEBUG.isEmpty(); 599 } 600 private static boolean isDebug(String flag) { 601 return DEBUG.equals(flag); 602 } 603 604 // ProxyBuilder instance members start here.... 605 606 private final ClassLoader loader; 607 private final List<Class<?>> interfaces; 608 private final Module module; 609 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) { 610 if (!VM.isModuleSystemInited()) { 611 throw new InternalError("Proxy is not supported until module system is fully initialized"); 612 } 613 if (interfaces.size() > 65535) { 614 throw new IllegalArgumentException("interface limit exceeded: " + interfaces.size()); 615 } 616 617 Set<Class<?>> refTypes = referencedTypes(loader, interfaces); 618 619 // IAE if violates any restrictions specified in newProxyInstance 620 validateProxyInterfaces(loader, interfaces, refTypes); 621 622 this.loader = loader; 623 this.interfaces = interfaces; 624 this.module = mapToModule(loader, interfaces, refTypes); 625 assert getLoader(module) == loader; 626 } 627 628 ProxyBuilder(ClassLoader loader, Class<?> intf) { 629 this(loader, Collections.singletonList(intf)); 630 } 631 632 /** 633 * Generate a proxy class and return its proxy Constructor with 634 * accessible flag already set. If the target module does not have access 635 * to any interface types, IllegalAccessError will be thrown by the VM 636 * at defineClass time. 637 * 638 * Must call the checkProxyAccess method to perform permission checks 639 * before calling this. 640 */ 641 Constructor<?> build() { 642 Class<?> proxyClass = defineProxyClass(module, interfaces); 643 final Constructor<?> cons; 644 try { 645 cons = proxyClass.getConstructor(constructorParams); 646 } catch (NoSuchMethodException e) { 647 throw new InternalError(e.toString(), e); 648 } 649 AccessController.doPrivileged(new PrivilegedAction<Void>() { 650 public Void run() { 651 cons.setAccessible(true); 652 return null; 653 } 654 }); 655 return cons; 656 } 657 658 /** 659 * Validate the given proxy interfaces and the given referenced types 660 * are visible to the defining loader. 661 * 662 * @throws IllegalArgumentException if it violates the restrictions specified 663 * in {@link Proxy#newProxyInstance} 664 */ 665 private static void validateProxyInterfaces(ClassLoader loader, 666 List<Class<?>> interfaces, 667 Set<Class<?>> refTypes) 668 { 669 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size()); 670 for (Class<?> intf : interfaces) { 671 /* 672 * Verify that the class loader resolves the name of this 673 * interface to the same Class object. 674 */ 675 ensureVisible(loader, intf); 676 677 /* 678 * Verify that the Class object actually represents an 679 * interface. 680 */ 681 if (!intf.isInterface()) { 682 throw new IllegalArgumentException(intf.getName() + " is not an interface"); 683 } 684 685 /* 686 * Verify that this interface is not a duplicate. 687 */ 688 if (interfaceSet.put(intf, Boolean.TRUE) != null) { 689 throw new IllegalArgumentException("repeated interface: " + intf.getName()); 690 } 691 } 692 693 for (Class<?> type : refTypes) { 694 ensureVisible(loader, type); 695 } 696 } 697 698 /* 699 * Returns all types referenced by all public non-static method signatures of 700 * the proxy interfaces 701 */ 702 private static Set<Class<?>> referencedTypes(ClassLoader loader, 703 List<Class<?>> interfaces) { 704 return interfaces.stream() 705 .flatMap(intf -> Stream.of(intf.getMethods()) 706 .filter(m -> !Modifier.isStatic(m.getModifiers())) 707 .flatMap(ProxyBuilder::methodRefTypes) 708 .map(ProxyBuilder::getElementType) 709 .filter(t -> !t.isPrimitive())) 710 .collect(Collectors.toSet()); 711 } 712 713 /* 714 * Extracts all types referenced on a method signature including 715 * its return type, parameter types, and exception types. 716 */ 717 private static Stream<Class<?>> methodRefTypes(Method m) { 718 return Stream.of(new Class<?>[] { m.getReturnType() }, 719 m.getParameterTypes(), 720 m.getExceptionTypes()) 721 .flatMap(Stream::of); 722 } 723 724 /** 725 * Returns the module that the generated proxy class belongs to. 726 * 727 * If all proxy interfaces are public and in exported packages, 728 * then the proxy class is in unnamed module. 729 * 730 * If any of proxy interface is package-private, then the proxy class 731 * is in the same module of the package-private interface. 732 * 733 * If all proxy interfaces are public and at least one in a non-exported 734 * package, then the proxy class is in a dynamic module in a non-exported 735 * package. Reads edge and qualified exports are added for 736 * dynamic module to access. 737 */ 738 private static Module mapToModule(ClassLoader loader, 739 List<Class<?>> interfaces, 740 Set<Class<?>> refTypes) { 741 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>(); 742 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>(); 743 for (Class<?> intf : interfaces) { 744 Module m = intf.getModule(); 745 if (Modifier.isPublic(intf.getModifiers())) { 746 // module-private types 747 if (!m.isExported(intf.getPackageName())) { 748 modulePrivateTypes.put(intf, m); 749 } 750 } else { 751 packagePrivateTypes.put(intf, m); 752 } 753 } 754 755 // all proxy interfaces are public and exported, the proxy class is in unnamed module 756 // Such proxy class is accessible to any unnamed module and named module that 757 // can read unnamed module 758 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) { 759 return loader != null ? loader.getUnnamedModule() : BootLoader.getUnnamedModule(); 760 } 761 762 if (packagePrivateTypes.size() > 0) { 763 // all package-private types must be in the same runtime package 764 // i.e. same package name and same module (named or unnamed) 765 // 766 // Configuration will fail if M1 and in M2 defined by the same loader 767 // and both have the same package p (so no need to check class loader) 768 if (packagePrivateTypes.size() > 1 && 769 (packagePrivateTypes.keySet().stream() // more than one package 770 .map(Class::getPackageName).distinct().count() > 1 || 771 packagePrivateTypes.values().stream() // or more than one module 772 .distinct().count() > 1)) { 773 throw new IllegalArgumentException( 774 "non-public interfaces from different packages"); 775 } 776 777 // all package-private types are in the same module (named or unnamed) 778 Module target = null; 779 for (Module m : packagePrivateTypes.values()) { 780 if (getLoader(m) != loader) { 781 // the specified loader is not the same class loader of the non-public interface 782 throw new IllegalArgumentException( 783 "non-public interface is not defined by the given loader"); 784 } 785 target = m; 786 } 787 788 // validate if the target module can access all other interfaces 789 for (Class<?> intf : interfaces) { 790 Module m = intf.getModule(); 791 if (m == target) continue; 792 793 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) { 794 throw new IllegalArgumentException(target + " can't access " + intf.getName()); 795 } 796 } 797 798 // return the module of the package-private interface 799 return target; 800 } 801 802 // all proxy interfaces are public and at least one in a non-exported package 803 // map to dynamic proxy module and add reads edge and qualified exports, if necessary 804 Module target = getDynamicModule(loader); 805 806 // set up proxy class access to proxy interfaces and types 807 // referenced in the method signature 808 Set<Class<?>> types = new HashSet<>(interfaces); 809 types.addAll(refTypes); 810 for (Class<?> c : types) { 811 ensureAccess(target, c); 812 } 813 return target; 814 } 815 816 /* 817 * Ensure the given module can access the given class. 818 */ 819 private static void ensureAccess(Module target, Class<?> c) { 820 Module m = c.getModule(); 821 // add read edge and qualified export for the target module to access 822 if (!target.canRead(m)) { 823 Modules.addReads(target, m); 824 } 825 String pn = c.getPackageName(); 826 if (!m.isExported(pn, target)) { 827 Modules.addExports(m, pn, target); 828 } 829 } 830 831 /* 832 * Ensure the given class is visible to the class loader. 833 */ 834 private static void ensureVisible(ClassLoader ld, Class<?> c) { 835 Class<?> type = null; 836 try { 837 type = Class.forName(c.getName(), false, ld); 838 } catch (ClassNotFoundException e) { 839 } 840 if (type != c) { 841 throw new IllegalArgumentException(c.getName() + 842 " referenced from a method is not visible from class loader"); 843 } 844 } 845 846 private static Class<?> getElementType(Class<?> type) { 847 Class<?> e = type; 848 while (e.isArray()) { 849 e = e.getComponentType(); 850 } 851 return e; 852 } 853 854 private static final ClassLoaderValue<Module> dynProxyModules = 855 new ClassLoaderValue<>(); 856 private static final AtomicInteger counter = new AtomicInteger(); 857 858 /* 859 * Define a dynamic module for the generated proxy classes in a non-exported package 860 * named com.sun.proxy.$MODULE. 861 * 862 * Each class loader will have one dynamic module. 863 */ 864 private static Module getDynamicModule(ClassLoader loader) { 865 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> { 866 // create a dynamic module and setup module access 867 String mn = "jdk.proxy" + counter.incrementAndGet(); 868 String pn = PROXY_PACKAGE_PREFIX + "." + mn; 869 ModuleDescriptor descriptor = 870 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC)) 871 .packages(Set.of(pn)) 872 .build(); 873 Module m = Modules.defineModule(ld, descriptor, null); 874 Modules.addReads(m, Proxy.class.getModule()); 875 // java.base to create proxy instance 876 Modules.addExports(m, pn, Object.class.getModule()); 877 return m; 878 }); 879 } 880 } 881 882 /** 883 * Returns a proxy instance for the specified interfaces 884 * that dispatches method invocations to the specified invocation 885 * handler. 886 * <p> 887 * <a name="restrictions">{@code IllegalArgumentException} will be thrown 888 * if any of the following restrictions is violated:</a> 889 * <ul> 890 * <li>All of {@code Class} objects in the given {@code interfaces} array 891 * must represent interfaces, not classes or primitive types. 892 * 893 * <li>No two elements in the {@code interfaces} array may 894 * refer to identical {@code Class} objects. 895 * 896 * <li>All of the interface types must be visible by name through the 897 * specified class loader. In other words, for class loader 898 * {@code cl} and every interface {@code i}, the following 899 * expression must be true:<p> 900 * {@code Class.forName(i.getName(), false, cl) == i} 901 * 902 * <li>All of the types referenced by all 903 * public method signatures of the specified interfaces 904 * and those inherited by their superinterfaces 905 * must be visible by name through the specified class loader. 906 * 907 * <li>All non-public interfaces must be in the same package 908 * and module, defined by the specified class loader and 909 * the module of the non-public interfaces can access all of 910 * the interface types; otherwise, it would not be possible for 911 * the proxy class to implement all of the interfaces, 912 * regardless of what package it is defined in. 913 * 914 * <li>For any set of member methods of the specified interfaces 915 * that have the same signature: 916 * <ul> 917 * <li>If the return type of any of the methods is a primitive 918 * type or void, then all of the methods must have that same 919 * return type. 920 * <li>Otherwise, one of the methods must have a return type that 921 * is assignable to all of the return types of the rest of the 922 * methods. 923 * </ul> 924 * 925 * <li>The resulting proxy class must not exceed any limits imposed 926 * on classes by the virtual machine. For example, the VM may limit 927 * the number of interfaces that a class may implement to 65535; in 928 * that case, the size of the {@code interfaces} array must not 929 * exceed 65535. 930 * </ul> 931 * 932 * <p>Note that the order of the specified proxy interfaces is 933 * significant: two requests for a proxy class with the same combination 934 * of interfaces but in a different order will result in two distinct 935 * proxy classes. 936 * 937 * @param loader the class loader to define the proxy class 938 * @param interfaces the list of interfaces for the proxy class 939 * to implement 940 * @param h the invocation handler to dispatch method invocations to 941 * @return a proxy instance with the specified invocation handler of a 942 * proxy class that is defined by the specified class loader 943 * and that implements the specified interfaces 944 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 945 * restrictions</a> on the parameters are violated 946 * @throws SecurityException if a security manager, <em>s</em>, is present 947 * and any of the following conditions is met: 948 * <ul> 949 * <li> the given {@code loader} is {@code null} and 950 * the caller's class loader is not {@code null} and the 951 * invocation of {@link SecurityManager#checkPermission 952 * s.checkPermission} with 953 * {@code RuntimePermission("getClassLoader")} permission 954 * denies access;</li> 955 * <li> for each proxy interface, {@code intf}, 956 * the caller's class loader is not the same as or an 957 * ancestor of the class loader for {@code intf} and 958 * invocation of {@link SecurityManager#checkPackageAccess 959 * s.checkPackageAccess()} denies access to {@code intf};</li> 960 * <li> any of the given proxy interfaces is non-public and the 961 * caller class is not in the same {@linkplain Package runtime package} 962 * as the non-public interface and the invocation of 963 * {@link SecurityManager#checkPermission s.checkPermission} with 964 * {@code ReflectPermission("newProxyInPackage.{package name}")} 965 * permission denies access.</li> 966 * </ul> 967 * @throws NullPointerException if the {@code interfaces} array 968 * argument or any of its elements are {@code null}, or 969 * if the invocation handler, {@code h}, is 970 * {@code null} 971 * 972 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 973 * @revised 9 974 * @spec JPMS 975 */ 976 @CallerSensitive 977 public static Object newProxyInstance(ClassLoader loader, 978 Class<?>[] interfaces, 979 InvocationHandler h) { 980 Objects.requireNonNull(h); 981 982 final Class<?> caller = System.getSecurityManager() == null 983 ? null 984 : Reflection.getCallerClass(); 985 986 /* 987 * Look up or generate the designated proxy class and its constructor. 988 */ 989 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces); 990 991 return newProxyInstance(caller, cons, h); 992 } 993 994 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager 995 Constructor<?> cons, 996 InvocationHandler h) { 997 /* 998 * Invoke its constructor with the designated invocation handler. 999 */ 1000 try { 1001 if (caller != null) { 1002 checkNewProxyPermission(caller, cons.getDeclaringClass()); 1003 } 1004 1005 return cons.newInstance(new Object[]{h}); 1006 } catch (IllegalAccessException | InstantiationException e) { 1007 throw new InternalError(e.toString(), e); 1008 } catch (InvocationTargetException e) { 1009 Throwable t = e.getCause(); 1010 if (t instanceof RuntimeException) { 1011 throw (RuntimeException) t; 1012 } else { 1013 throw new InternalError(t.toString(), t); 1014 } 1015 } 1016 } 1017 1018 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) { 1019 SecurityManager sm = System.getSecurityManager(); 1020 if (sm != null) { 1021 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) { 1022 ClassLoader ccl = caller.getClassLoader(); 1023 ClassLoader pcl = proxyClass.getClassLoader(); 1024 1025 // do permission check if the caller is in a different runtime package 1026 // of the proxy class 1027 int n = proxyClass.getName().lastIndexOf('.'); 1028 String pkg = (n == -1) ? "" : proxyClass.getName().substring(0, n); 1029 1030 n = caller.getName().lastIndexOf('.'); 1031 String callerPkg = (n == -1) ? "" : caller.getName().substring(0, n); 1032 1033 if (pcl != ccl || !pkg.equals(callerPkg)) { 1034 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg)); 1035 } 1036 } 1037 } 1038 } 1039 1040 /** 1041 * Returns the class loader for the given module. 1042 */ 1043 private static ClassLoader getLoader(Module m) { 1044 PrivilegedAction<ClassLoader> pa = m::getClassLoader; 1045 return AccessController.doPrivileged(pa); 1046 } 1047 1048 /** 1049 * Returns true if the given class is a proxy class. 1050 * 1051 * @implNote The reliability of this method is important for the ability 1052 * to use it to make security decisions, so its implementation should 1053 * not just test if the class in question extends {@code Proxy}. 1054 * 1055 * @param cl the class to test 1056 * @return {@code true} if the class is a proxy class and 1057 * {@code false} otherwise 1058 * @throws NullPointerException if {@code cl} is {@code null} 1059 * 1060 * @revised 9 1061 * @spec JPMS 1062 */ 1063 public static boolean isProxyClass(Class<?> cl) { 1064 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl); 1065 } 1066 1067 /** 1068 * Returns the invocation handler for the specified proxy instance. 1069 * 1070 * @param proxy the proxy instance to return the invocation handler for 1071 * @return the invocation handler for the proxy instance 1072 * @throws IllegalArgumentException if the argument is not a 1073 * proxy instance 1074 * @throws SecurityException if a security manager, <em>s</em>, is present 1075 * and the caller's class loader is not the same as or an 1076 * ancestor of the class loader for the invocation handler 1077 * and invocation of {@link SecurityManager#checkPackageAccess 1078 * s.checkPackageAccess()} denies access to the invocation 1079 * handler's class. 1080 */ 1081 @CallerSensitive 1082 public static InvocationHandler getInvocationHandler(Object proxy) 1083 throws IllegalArgumentException 1084 { 1085 /* 1086 * Verify that the object is actually a proxy instance. 1087 */ 1088 if (!isProxyClass(proxy.getClass())) { 1089 throw new IllegalArgumentException("not a proxy instance"); 1090 } 1091 1092 final Proxy p = (Proxy) proxy; 1093 final InvocationHandler ih = p.h; 1094 if (System.getSecurityManager() != null) { 1095 Class<?> ihClass = ih.getClass(); 1096 Class<?> caller = Reflection.getCallerClass(); 1097 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(), 1098 ihClass.getClassLoader())) 1099 { 1100 ReflectUtil.checkPackageAccess(ihClass); 1101 } 1102 } 1103 1104 return ih; 1105 } 1106 1107 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0]; 1108 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE; 1109 }