1 /* 2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.reflect; 27 28 import java.lang.module.ModuleDescriptor; 29 import java.security.AccessController; 30 import java.security.PrivilegedAction; 31 import java.util.Arrays; 32 import java.util.Collections; 33 import java.util.HashMap; 34 import java.util.HashSet; 35 import java.util.IdentityHashMap; 36 import java.util.List; 37 import java.util.Map; 38 import java.util.Objects; 39 import java.util.Set; 40 import java.util.concurrent.atomic.AtomicInteger; 41 import java.util.concurrent.atomic.AtomicLong; 42 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 363 * and not accessible to code outside its module. 364 * {@link Constructor#newInstance(Object...) Constructor.newInstance} 365 * will throw {@code IllegalAccessException} when it is called on 366 * an inaccessible proxy class. 367 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)} 368 * to create a proxy instance instead. 369 * 370 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 371 * @revised 9 372 * @spec JPMS 373 */ 374 @Deprecated 375 @CallerSensitive 376 public static Class<?> getProxyClass(ClassLoader loader, 377 Class<?>... interfaces) 378 throws IllegalArgumentException 379 { 380 Class<?> caller = System.getSecurityManager() == null 381 ? null 382 : Reflection.getCallerClass(); 383 384 return getProxyConstructor(caller, loader, interfaces) 385 .getDeclaringClass(); 386 } 387 388 /** 389 * Returns the {@code Constructor} object of a proxy class that takes a 390 * single argument of type {@link InvocationHandler}, given a class loader 391 * and an array of interfaces. The returned constructor will have the 392 * {@link Constructor#setAccessible(boolean) accessible} flag already set. 393 * 394 * @param caller passed from a public-facing @CallerSensitive method if 395 * SecurityManager is set or {@code null} if there's no 396 * SecurityManager 397 * @param loader the class loader to define the proxy class 398 * @param interfaces the list of interfaces for the proxy class 399 * to implement 400 * @return a Constructor of the proxy class taking single 401 * {@code InvocationHandler} parameter 402 */ 403 private static Constructor<?> getProxyConstructor(Class<?> caller, 404 ClassLoader loader, 405 Class<?>... interfaces) 406 { 407 // optimization for single interface 408 if (interfaces.length == 1) { 409 Class<?> intf = interfaces[0]; 410 if (caller != null) { 411 checkProxyAccess(caller, loader, intf); 412 } 413 return proxyCache.sub(intf).computeIfAbsent( 414 loader, 415 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 416 ); 417 } else { 418 // interfaces cloned 419 final Class<?>[] intfsArray = interfaces.clone(); 420 if (caller != null) { 421 checkProxyAccess(caller, loader, intfsArray); 422 } 423 final List<Class<?>> intfs = Arrays.asList(intfsArray); 424 return proxyCache.sub(intfs).computeIfAbsent( 425 loader, 426 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 427 ); 428 } 429 } 430 431 /* 432 * Check permissions required to create a Proxy class. 433 * 434 * To define a proxy class, it performs the access checks as in 435 * Class.forName (VM will invoke ClassLoader.checkPackageAccess): 436 * 1. "getClassLoader" permission check if loader == null 437 * 2. checkPackageAccess on the interfaces it implements 438 * 439 * To get a constructor and new instance of a proxy class, it performs 440 * the package access check on the interfaces it implements 441 * as in Class.getConstructor. 442 * 443 * If an interface is non-public, the proxy class must be defined by 444 * the defining loader of the interface. If the caller's class loader 445 * is not the same as the defining loader of the interface, the VM 446 * will throw IllegalAccessError when the generated proxy class is 447 * being defined. 448 */ 449 private static void checkProxyAccess(Class<?> caller, 450 ClassLoader loader, 451 Class<?> ... interfaces) 452 { 453 SecurityManager sm = System.getSecurityManager(); 454 if (sm != null) { 455 ClassLoader ccl = caller.getClassLoader(); 456 if (VM.isSystemDomainLoader(loader) && !VM.isSystemDomainLoader(ccl)) { 457 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 458 } 459 ReflectUtil.checkProxyPackageAccess(ccl, interfaces); 460 } 461 } 462 463 /** 464 * Builder for a proxy class. 465 * 466 * If the module is not specified in this ProxyBuilder constructor, 467 * it will map from the given loader and interfaces to the module 468 * in which the proxy class will be defined. 469 */ 470 private static final class ProxyBuilder { 471 private static final Unsafe UNSAFE = Unsafe.getUnsafe(); 472 473 // prefix for all proxy class names 474 private static final String proxyClassNamePrefix = "$Proxy"; 475 476 // next number to use for generation of unique proxy class names 477 private static final AtomicLong nextUniqueNumber = new AtomicLong(); 478 479 // a reverse cache of defined proxy classes 480 private static final ClassLoaderValue<Boolean> reverseProxyCache = 481 new ClassLoaderValue<>(); 482 483 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) { 484 String proxyPkg = null; // package to define proxy class in 485 int accessFlags = Modifier.PUBLIC | Modifier.FINAL; 486 487 /* 488 * Record the package of a non-public proxy interface so that the 489 * proxy class will be defined in the same package. Verify that 490 * all non-public proxy interfaces are in the same package. 491 */ 492 for (Class<?> intf : interfaces) { 493 int flags = intf.getModifiers(); 494 if (!Modifier.isPublic(flags)) { 495 accessFlags = Modifier.FINAL; // non-public, final 496 String pkg = intf.getPackageName(); 497 if (proxyPkg == null) { 498 proxyPkg = pkg; 499 } else if (!pkg.equals(proxyPkg)) { 500 throw new IllegalArgumentException( 501 "non-public interfaces from different packages"); 502 } 503 } 504 } 505 506 if (proxyPkg == null) { 507 // all proxy interfaces are public 508 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName() 509 : PROXY_PACKAGE_PREFIX; 510 } else if (proxyPkg.isEmpty() && m.isNamed()) { 511 throw new IllegalArgumentException( 512 "Unnamed package cannot be added to " + m); 513 } 514 515 if (m.isNamed()) { 516 if (!m.getDescriptor().packages().contains(proxyPkg)) { 517 throw new InternalError(proxyPkg + " not exist in " + m.getName()); 518 } 519 } 520 521 /* 522 * Choose a name for the proxy class to generate. 523 */ 524 long num = nextUniqueNumber.getAndIncrement(); 525 String proxyName = proxyPkg.isEmpty() 526 ? proxyClassNamePrefix + num 527 : proxyPkg + "." + proxyClassNamePrefix + num; 528 529 ClassLoader loader = getLoader(m); 530 trace(proxyName, m, loader, interfaces); 531 532 /* 533 * Generate the specified proxy class. 534 */ 535 byte[] proxyClassFile = ProxyGenerator.generateProxyClass( 536 proxyName, interfaces.toArray(EMPTY_CLASS_ARRAY), accessFlags); 537 try { 538 Class<?> pc = UNSAFE.defineClass(proxyName, proxyClassFile, 539 0, proxyClassFile.length, 540 loader, null); 541 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE); 542 return pc; 543 } catch (ClassFormatError e) { 544 /* 545 * A ClassFormatError here means that (barring bugs in the 546 * proxy class generation code) there was some other 547 * invalid aspect of the arguments supplied to the proxy 548 * class creation (such as virtual machine limitations 549 * exceeded). 550 */ 551 throw new IllegalArgumentException(e.toString()); 552 } 553 } 554 555 /** 556 * Test if given class is a class defined by 557 * {@link #defineProxyClass(Module, List)} 558 */ 559 static boolean isProxyClass(Class<?> c) { 560 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()), 561 Boolean.TRUE); 562 } 563 564 private static boolean isExportedType(Class<?> c) { 565 String pn = c.getPackageName(); 566 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn); 567 } 568 569 private static boolean isPackagePrivateType(Class<?> c) { 570 return !Modifier.isPublic(c.getModifiers()); 571 } 572 573 private static String toDetails(Class<?> c) { 574 String access = "unknown"; 575 if (isExportedType(c)) { 576 access = "exported"; 577 } else if (isPackagePrivateType(c)) { 578 access = "package-private"; 579 } else { 580 access = "module-private"; 581 } 582 ClassLoader ld = c.getClassLoader(); 583 return String.format(" %s/%s %s loader %s", 584 c.getModule().getName(), c.getName(), access, ld); 585 } 586 587 static void trace(String cn, 588 Module module, 589 ClassLoader loader, 590 List<Class<?>> interfaces) { 591 if (isDebug()) { 592 System.err.format("PROXY: %s/%s defined by %s%n", 593 module.getName(), cn, loader); 594 } 595 if (isDebug("debug")) { 596 interfaces.stream() 597 .forEach(c -> System.out.println(toDetails(c))); 598 } 599 } 600 601 private static final String DEBUG = 602 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", ""); 603 604 private static boolean isDebug() { 605 return !DEBUG.isEmpty(); 606 } 607 private static boolean isDebug(String flag) { 608 return DEBUG.equals(flag); 609 } 610 611 // ProxyBuilder instance members start here.... 612 613 private final List<Class<?>> interfaces; 614 private final Module module; 615 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) { 616 if (!VM.isModuleSystemInited()) { 617 throw new InternalError("Proxy is not supported until " 618 + "module system is fully initialized"); 619 } 620 if (interfaces.size() > 65535) { 621 throw new IllegalArgumentException("interface limit exceeded: " 622 + interfaces.size()); 623 } 624 625 Set<Class<?>> refTypes = referencedTypes(loader, interfaces); 626 627 // IAE if violates any restrictions specified in newProxyInstance 628 validateProxyInterfaces(loader, interfaces, refTypes); 629 630 this.interfaces = interfaces; 631 this.module = mapToModule(loader, interfaces, refTypes); 632 assert getLoader(module) == loader; 633 } 634 635 ProxyBuilder(ClassLoader loader, Class<?> intf) { 636 this(loader, Collections.singletonList(intf)); 637 } 638 639 /** 640 * Generate a proxy class and return its proxy Constructor with 641 * accessible flag already set. If the target module does not have access 642 * to any interface types, IllegalAccessError will be thrown by the VM 643 * at defineClass time. 644 * 645 * Must call the checkProxyAccess method to perform permission checks 646 * before calling this. 647 */ 648 Constructor<?> build() { 649 Class<?> proxyClass = defineProxyClass(module, interfaces); 650 final Constructor<?> cons; 651 try { 652 cons = proxyClass.getConstructor(constructorParams); 653 } catch (NoSuchMethodException e) { 654 throw new InternalError(e.toString(), e); 655 } 656 AccessController.doPrivileged(new PrivilegedAction<Void>() { 657 public Void run() { 658 cons.setAccessible(true); 659 return null; 660 } 661 }); 662 return cons; 663 } 664 665 /** 666 * Validate the given proxy interfaces and the given referenced types 667 * are visible to the defining loader. 668 * 669 * @throws IllegalArgumentException if it violates the restrictions 670 * specified in {@link Proxy#newProxyInstance} 671 */ 672 private static void validateProxyInterfaces(ClassLoader loader, 673 List<Class<?>> interfaces, 674 Set<Class<?>> refTypes) 675 { 676 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size()); 677 for (Class<?> intf : interfaces) { 678 /* 679 * Verify that the class loader resolves the name of this 680 * interface to the same Class object. 681 */ 682 ensureVisible(loader, intf); 683 684 /* 685 * Verify that the Class object actually represents an 686 * interface. 687 */ 688 if (!intf.isInterface()) { 689 throw new IllegalArgumentException(intf.getName() + " is not an interface"); 690 } 691 692 /* 693 * Verify that this interface is not a duplicate. 694 */ 695 if (interfaceSet.put(intf, Boolean.TRUE) != null) { 696 throw new IllegalArgumentException("repeated interface: " + intf.getName()); 697 } 698 } 699 700 for (Class<?> type : refTypes) { 701 ensureVisible(loader, type); 702 } 703 } 704 705 /* 706 * Returns all types referenced by all public non-static method signatures of 707 * the proxy interfaces 708 */ 709 private static Set<Class<?>> referencedTypes(ClassLoader loader, 710 List<Class<?>> interfaces) { 711 return interfaces.stream() 712 .flatMap(intf -> Stream.of(intf.getMethods()) 713 .filter(m -> !Modifier.isStatic(m.getModifiers())) 714 .flatMap(ProxyBuilder::methodRefTypes) 715 .map(ProxyBuilder::getElementType) 716 .filter(t -> !t.isPrimitive())) 717 .collect(Collectors.toSet()); 718 } 719 720 /* 721 * Extracts all types referenced on a method signature including 722 * its return type, parameter types, and exception types. 723 */ 724 private static Stream<Class<?>> methodRefTypes(Method m) { 725 return Stream.of(new Class<?>[] { m.getReturnType() }, 726 m.getParameterTypes(), 727 m.getExceptionTypes()) 728 .flatMap(Stream::of); 729 } 730 731 /** 732 * Returns the module that the generated proxy class belongs to. 733 * 734 * If all proxy interfaces are public and in exported packages, 735 * then the proxy class is in unnamed module. 736 * 737 * If any of proxy interface is package-private, then the proxy class 738 * is in the same module of the package-private interface. 739 * 740 * If all proxy interfaces are public and at least one in a non-exported 741 * package, then the proxy class is in a dynamic module in a 742 * non-exported package. Reads edge and qualified exports are added 743 * for dynamic module to access. 744 */ 745 private static Module mapToModule(ClassLoader loader, 746 List<Class<?>> interfaces, 747 Set<Class<?>> refTypes) { 748 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>(); 749 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>(); 750 for (Class<?> intf : interfaces) { 751 Module m = intf.getModule(); 752 if (Modifier.isPublic(intf.getModifiers())) { 753 // module-private types 754 if (!m.isExported(intf.getPackageName())) { 755 modulePrivateTypes.put(intf, m); 756 } 757 } else { 758 packagePrivateTypes.put(intf, m); 759 } 760 } 761 762 // all proxy interfaces are public and exported, the proxy class 763 // is in unnamed module. Such proxy class is accessible to 764 // any unnamed module and named module that can read unnamed module 765 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) { 766 return loader != null ? loader.getUnnamedModule() 767 : BootLoader.getUnnamedModule(); 768 } 769 770 if (packagePrivateTypes.size() > 0) { 771 // all package-private types must be in the same runtime package 772 // i.e. same package name and same module (named or unnamed) 773 // 774 // Configuration will fail if M1 and in M2 defined by the same loader 775 // and both have the same package p (so no need to check class loader) 776 if (packagePrivateTypes.size() > 1 && 777 (packagePrivateTypes.keySet().stream() // more than one package 778 .map(Class::getPackageName).distinct().count() > 1 || 779 packagePrivateTypes.values().stream() // or more than one module 780 .distinct().count() > 1)) { 781 throw new IllegalArgumentException( 782 "non-public interfaces from different packages"); 783 } 784 785 // all package-private types are in the same module (named or unnamed) 786 Module target = null; 787 for (Module m : packagePrivateTypes.values()) { 788 if (getLoader(m) != loader) { 789 // the specified loader is not the same class loader 790 // of the non-public interface 791 throw new IllegalArgumentException( 792 "non-public interface is not defined by the given loader"); 793 } 794 target = m; 795 } 796 797 // validate if the target module can access all other interfaces 798 for (Class<?> intf : interfaces) { 799 Module m = intf.getModule(); 800 if (m == target) continue; 801 802 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) { 803 throw new IllegalArgumentException(target + " can't access " + intf.getName()); 804 } 805 } 806 807 // return the module of the package-private interface 808 return target; 809 } 810 811 // All proxy interfaces are public and at least one in a non-exported 812 // package. So maps to a dynamic proxy module and add reads edge 813 // and qualified exports, if necessary 814 Module target = getDynamicModule(loader); 815 816 // set up proxy class access to proxy interfaces and types 817 // referenced in the method signature 818 Set<Class<?>> types = new HashSet<>(interfaces); 819 types.addAll(refTypes); 820 for (Class<?> c : types) { 821 ensureAccess(target, c); 822 } 823 return target; 824 } 825 826 /* 827 * Ensure the given module can access the given class. 828 */ 829 private static void ensureAccess(Module target, Class<?> c) { 830 Module m = c.getModule(); 831 // add read edge and qualified export for the target module to access 832 if (!target.canRead(m)) { 833 Modules.addReads(target, m); 834 } 835 String pn = c.getPackageName(); 836 if (!m.isExported(pn, target)) { 837 Modules.addExports(m, pn, target); 838 } 839 } 840 841 /* 842 * Ensure the given class is visible to the class loader. 843 */ 844 private static void ensureVisible(ClassLoader ld, Class<?> c) { 845 Class<?> type = null; 846 try { 847 type = Class.forName(c.getName(), false, ld); 848 } catch (ClassNotFoundException e) { 849 } 850 if (type != c) { 851 throw new IllegalArgumentException(c.getName() + 852 " referenced from a method is not visible from class loader"); 853 } 854 } 855 856 private static Class<?> getElementType(Class<?> type) { 857 Class<?> e = type; 858 while (e.isArray()) { 859 e = e.getComponentType(); 860 } 861 return e; 862 } 863 864 private static final ClassLoaderValue<Module> dynProxyModules = 865 new ClassLoaderValue<>(); 866 private static final AtomicInteger counter = new AtomicInteger(); 867 868 /* 869 * Define a dynamic module for the generated proxy classes in 870 * a non-exported package named com.sun.proxy.$MODULE. 871 * 872 * Each class loader will have one dynamic module. 873 */ 874 private static Module getDynamicModule(ClassLoader loader) { 875 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> { 876 // create a dynamic module and setup module access 877 String mn = "jdk.proxy" + counter.incrementAndGet(); 878 String pn = PROXY_PACKAGE_PREFIX + "." + mn; 879 ModuleDescriptor descriptor = 880 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC)) 881 .packages(Set.of(pn)) 882 .build(); 883 Module m = Modules.defineModule(ld, descriptor, null); 884 Modules.addReads(m, Proxy.class.getModule()); 885 // java.base to create proxy instance 886 Modules.addExports(m, pn, Object.class.getModule()); 887 return m; 888 }); 889 } 890 } 891 892 /** 893 * Returns a proxy instance for the specified interfaces 894 * that dispatches method invocations to the specified invocation 895 * handler. 896 * <p> 897 * <a name="restrictions">{@code IllegalArgumentException} will be thrown 898 * if any of the following restrictions is violated:</a> 899 * <ul> 900 * <li>All of {@code Class} objects in the given {@code interfaces} array 901 * must represent interfaces, not classes or primitive types. 902 * 903 * <li>No two elements in the {@code interfaces} array may 904 * refer to identical {@code Class} objects. 905 * 906 * <li>All of the interface types must be visible by name through the 907 * specified class loader. In other words, for class loader 908 * {@code cl} and every interface {@code i}, the following 909 * expression must be true:<p> 910 * {@code Class.forName(i.getName(), false, cl) == i} 911 * 912 * <li>All of the types referenced by all 913 * public method signatures of the specified interfaces 914 * and those inherited by their superinterfaces 915 * must be visible by name through the specified class loader. 916 * 917 * <li>All non-public interfaces must be in the same package 918 * and module, defined by the specified class loader and 919 * the module of the non-public interfaces can access all of 920 * the interface types; otherwise, it would not be possible for 921 * the proxy class to implement all of the interfaces, 922 * regardless of what package it is defined in. 923 * 924 * <li>For any set of member methods of the specified interfaces 925 * that have the same signature: 926 * <ul> 927 * <li>If the return type of any of the methods is a primitive 928 * type or void, then all of the methods must have that same 929 * return type. 930 * <li>Otherwise, one of the methods must have a return type that 931 * is assignable to all of the return types of the rest of the 932 * methods. 933 * </ul> 934 * 935 * <li>The resulting proxy class must not exceed any limits imposed 936 * on classes by the virtual machine. For example, the VM may limit 937 * the number of interfaces that a class may implement to 65535; in 938 * that case, the size of the {@code interfaces} array must not 939 * exceed 65535. 940 * </ul> 941 * 942 * <p>Note that the order of the specified proxy interfaces is 943 * significant: two requests for a proxy class with the same combination 944 * of interfaces but in a different order will result in two distinct 945 * proxy classes. 946 * 947 * @param loader the class loader to define the proxy class 948 * @param interfaces the list of interfaces for the proxy class 949 * to implement 950 * @param h the invocation handler to dispatch method invocations to 951 * @return a proxy instance with the specified invocation handler of a 952 * proxy class that is defined by the specified class loader 953 * and that implements the specified interfaces 954 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 955 * restrictions</a> on the parameters are violated 956 * @throws SecurityException if a security manager, <em>s</em>, is present 957 * and any of the following conditions is met: 958 * <ul> 959 * <li> the given {@code loader} is {@code null} and 960 * the caller's class loader is not {@code null} and the 961 * invocation of {@link SecurityManager#checkPermission 962 * s.checkPermission} with 963 * {@code RuntimePermission("getClassLoader")} permission 964 * denies access;</li> 965 * <li> for each proxy interface, {@code intf}, 966 * the caller's class loader is not the same as or an 967 * ancestor of the class loader for {@code intf} and 968 * invocation of {@link SecurityManager#checkPackageAccess 969 * s.checkPackageAccess()} denies access to {@code intf};</li> 970 * <li> any of the given proxy interfaces is non-public and the 971 * caller class is not in the same {@linkplain Package runtime package} 972 * as the non-public interface and the invocation of 973 * {@link SecurityManager#checkPermission s.checkPermission} with 974 * {@code ReflectPermission("newProxyInPackage.{package name}")} 975 * permission denies access.</li> 976 * </ul> 977 * @throws NullPointerException if the {@code interfaces} array 978 * argument or any of its elements are {@code null}, or 979 * if the invocation handler, {@code h}, is 980 * {@code null} 981 * 982 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 983 * @revised 9 984 * @spec JPMS 985 */ 986 @CallerSensitive 987 public static Object newProxyInstance(ClassLoader loader, 988 Class<?>[] interfaces, 989 InvocationHandler h) { 990 Objects.requireNonNull(h); 991 992 final Class<?> caller = System.getSecurityManager() == null 993 ? null 994 : Reflection.getCallerClass(); 995 996 /* 997 * Look up or generate the designated proxy class and its constructor. 998 */ 999 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces); 1000 1001 return newProxyInstance(caller, cons, h); 1002 } 1003 1004 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager 1005 Constructor<?> cons, 1006 InvocationHandler h) { 1007 /* 1008 * Invoke its constructor with the designated invocation handler. 1009 */ 1010 try { 1011 if (caller != null) { 1012 checkNewProxyPermission(caller, cons.getDeclaringClass()); 1013 } 1014 1015 return cons.newInstance(new Object[]{h}); 1016 } catch (IllegalAccessException | InstantiationException e) { 1017 throw new InternalError(e.toString(), e); 1018 } catch (InvocationTargetException e) { 1019 Throwable t = e.getCause(); 1020 if (t instanceof RuntimeException) { 1021 throw (RuntimeException) t; 1022 } else { 1023 throw new InternalError(t.toString(), t); 1024 } 1025 } 1026 } 1027 1028 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) { 1029 SecurityManager sm = System.getSecurityManager(); 1030 if (sm != null) { 1031 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) { 1032 ClassLoader ccl = caller.getClassLoader(); 1033 ClassLoader pcl = proxyClass.getClassLoader(); 1034 1035 // do permission check if the caller is in a different runtime package 1036 // of the proxy class 1037 int n = proxyClass.getName().lastIndexOf('.'); 1038 String pkg = (n == -1) ? "" : proxyClass.getName().substring(0, n); 1039 1040 n = caller.getName().lastIndexOf('.'); 1041 String callerPkg = (n == -1) ? "" : caller.getName().substring(0, n); 1042 1043 if (pcl != ccl || !pkg.equals(callerPkg)) { 1044 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg)); 1045 } 1046 } 1047 } 1048 } 1049 1050 /** 1051 * Returns the class loader for the given module. 1052 */ 1053 private static ClassLoader getLoader(Module m) { 1054 PrivilegedAction<ClassLoader> pa = m::getClassLoader; 1055 return AccessController.doPrivileged(pa); 1056 } 1057 1058 /** 1059 * Returns true if the given class is a proxy class. 1060 * 1061 * @implNote The reliability of this method is important for the ability 1062 * to use it to make security decisions, so its implementation should 1063 * not just test if the class in question extends {@code Proxy}. 1064 * 1065 * @param cl the class to test 1066 * @return {@code true} if the class is a proxy class and 1067 * {@code false} otherwise 1068 * @throws NullPointerException if {@code cl} is {@code null} 1069 * 1070 * @revised 9 1071 * @spec JPMS 1072 */ 1073 public static boolean isProxyClass(Class<?> cl) { 1074 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl); 1075 } 1076 1077 /** 1078 * Returns the invocation handler for the specified proxy instance. 1079 * 1080 * @param proxy the proxy instance to return the invocation handler for 1081 * @return the invocation handler for the proxy instance 1082 * @throws IllegalArgumentException if the argument is not a 1083 * proxy instance 1084 * @throws SecurityException if a security manager, <em>s</em>, is present 1085 * and the caller's class loader is not the same as or an 1086 * ancestor of the class loader for the invocation handler 1087 * and invocation of {@link SecurityManager#checkPackageAccess 1088 * s.checkPackageAccess()} denies access to the invocation 1089 * handler's class. 1090 */ 1091 @CallerSensitive 1092 public static InvocationHandler getInvocationHandler(Object proxy) 1093 throws IllegalArgumentException 1094 { 1095 /* 1096 * Verify that the object is actually a proxy instance. 1097 */ 1098 if (!isProxyClass(proxy.getClass())) { 1099 throw new IllegalArgumentException("not a proxy instance"); 1100 } 1101 1102 final Proxy p = (Proxy) proxy; 1103 final InvocationHandler ih = p.h; 1104 if (System.getSecurityManager() != null) { 1105 Class<?> ihClass = ih.getClass(); 1106 Class<?> caller = Reflection.getCallerClass(); 1107 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(), 1108 ihClass.getClassLoader())) 1109 { 1110 ReflectUtil.checkPackageAccess(ihClass); 1111 } 1112 } 1113 1114 return ih; 1115 } 1116 1117 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0]; 1118 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE; 1119 }