1 /* 2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.reflect; 27 28 import java.lang.module.ModuleDescriptor; 29 import java.security.AccessController; 30 import java.security.PrivilegedAction; 31 import java.util.Arrays; 32 import java.util.Collections; 33 import java.util.HashMap; 34 import java.util.HashSet; 35 import java.util.IdentityHashMap; 36 import java.util.List; 37 import java.util.Map; 38 import java.util.Objects; 39 import java.util.Set; 40 import java.util.concurrent.atomic.AtomicInteger; 41 import java.util.concurrent.atomic.AtomicLong; 42 43 import jdk.internal.access.JavaLangAccess; 44 import jdk.internal.access.SharedSecrets; 45 import jdk.internal.loader.BootLoader; 46 import jdk.internal.module.Modules; 47 import jdk.internal.misc.VM; 48 import jdk.internal.reflect.CallerSensitive; 49 import jdk.internal.reflect.Reflection; 50 import jdk.internal.loader.ClassLoaderValue; 51 import sun.reflect.misc.ReflectUtil; 52 import sun.security.action.GetBooleanAction; 53 import sun.security.action.GetPropertyAction; 54 import sun.security.util.SecurityConstants; 55 56 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC; 57 58 59 /** 60 * 61 * {@code Proxy} provides static methods for creating objects that act like instances 62 * of interfaces but allow for customized method invocation. 63 * To create a proxy instance for some interface {@code Foo}: 64 * <pre>{@code 65 * InvocationHandler handler = new MyInvocationHandler(...); 66 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(), 67 * new Class<?>[] { Foo.class }, 68 * handler); 69 * }</pre> 70 * 71 * <p> 72 * A <em>proxy class</em> is a class created at runtime that implements a specified 73 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em> 74 * is an instance of a proxy class. 75 * 76 * Each proxy instance has an associated <i>invocation handler</i> 77 * object, which implements the interface {@link InvocationHandler}. 78 * A method invocation on a proxy instance through one of its proxy 79 * interfaces will be dispatched to the {@link InvocationHandler#invoke 80 * invoke} method of the instance's invocation handler, passing the proxy 81 * instance, a {@code java.lang.reflect.Method} object identifying 82 * the method that was invoked, and an array of type {@code Object} 83 * containing the arguments. The invocation handler processes the 84 * encoded method invocation as appropriate and the result that it 85 * returns will be returned as the result of the method invocation on 86 * the proxy instance. 87 * 88 * <p>A proxy class has the following properties: 89 * 90 * <ul> 91 * <li>The unqualified name of a proxy class is unspecified. The space 92 * of class names that begin with the string {@code "$Proxy"} 93 * should be, however, reserved for proxy classes. 94 * 95 * <li>The package and module in which a proxy class is defined is specified 96 * <a href="#membership">below</a>. 97 * 98 * <li>A proxy class is <em>final and non-abstract</em>. 99 * 100 * <li>A proxy class extends {@code java.lang.reflect.Proxy}. 101 * 102 * <li>A proxy class implements exactly the interfaces specified at its 103 * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces} 104 * on its {@code Class} object will return an array containing the same 105 * list of interfaces (in the order specified at its creation), invoking 106 * {@link Class#getMethods getMethods} on its {@code Class} object will return 107 * an array of {@code Method} objects that include all of the 108 * methods in those interfaces, and invoking {@code getMethod} will 109 * find methods in the proxy interfaces as would be expected. 110 * 111 * <li>The {@link java.security.ProtectionDomain} of a proxy class 112 * is the same as that of system classes loaded by the bootstrap class 113 * loader, such as {@code java.lang.Object}, because the code for a 114 * proxy class is generated by trusted system code. This protection 115 * domain will typically be granted {@code java.security.AllPermission}. 116 * 117 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used 118 * to determine if a given class is a proxy class. 119 * </ul> 120 * 121 * <p>A proxy instance has the following properties: 122 * 123 * <ul> 124 * <li>Given a proxy instance {@code proxy} and one of the 125 * interfaces, {@code Foo}, implemented by its proxy class, the 126 * following expression will return true: 127 * <pre> 128 * {@code proxy instanceof Foo} 129 * </pre> 130 * and the following cast operation will succeed (rather than throwing 131 * a {@code ClassCastException}): 132 * <pre> 133 * {@code (Foo) proxy} 134 * </pre> 135 * 136 * <li>Each proxy instance has an associated invocation handler, the one 137 * that was passed to its constructor. The static 138 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method 139 * will return the invocation handler associated with the proxy instance 140 * passed as its argument. 141 * 142 * <li>An interface method invocation on a proxy instance will be 143 * encoded and dispatched to the invocation handler's {@link 144 * InvocationHandler#invoke invoke} method as described in the 145 * documentation for that method. 146 * 147 * <li>An invocation of the {@code hashCode}, 148 * {@code equals}, or {@code toString} methods declared in 149 * {@code java.lang.Object} on a proxy instance will be encoded and 150 * dispatched to the invocation handler's {@code invoke} method in 151 * the same manner as interface method invocations are encoded and 152 * dispatched, as described above. The declaring class of the 153 * {@code Method} object passed to {@code invoke} will be 154 * {@code java.lang.Object}. Other public methods of a proxy 155 * instance inherited from {@code java.lang.Object} are not 156 * overridden by a proxy class, so invocations of those methods behave 157 * like they do for instances of {@code java.lang.Object}. 158 * </ul> 159 * 160 * <h2><a id="membership">Package and Module Membership of Proxy Class</a></h2> 161 * 162 * The package and module to which a proxy class belongs are chosen such that 163 * the accessibility of the proxy class is in line with the accessibility of 164 * the proxy interfaces. Specifically, the package and the module membership 165 * of a proxy class defined via the 166 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or 167 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)} 168 * methods is specified as follows: 169 * 170 * <ol> 171 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em> 172 * packages: 173 * <ol type="a"> 174 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is 175 * <em>public</em> in a package exported by the 176 * {@linkplain ClassLoader#getUnnamedModule() unnamed module} of the specified 177 * loader. The name of the package is unspecified.</li> 178 * 179 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then 180 * the proxy class is <em>non-public</em> in the package and module of the 181 * non-public interfaces. All the non-public interfaces must be in the same 182 * package and module; otherwise, proxying them is 183 * <a href="#restrictions">not possible</a>.</li> 184 * </ol> 185 * </li> 186 * <li>If at least one proxy interface is in a package that is 187 * <em>non-exported</em> and <em>non-open</em>: 188 * <ol type="a"> 189 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is 190 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of 191 * <a href="#dynamicmodule"><em>dynamic module</em>.</a> 192 * The names of the package and the module are unspecified.</li> 193 * 194 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then 195 * the proxy class is <em>non-public</em> in the package and module of the 196 * non-public interfaces. All the non-public interfaces must be in the same 197 * package and module; otherwise, proxying them is 198 * <a href="#restrictions">not possible</a>.</li> 199 * </ol> 200 * </li> 201 * </ol> 202 * 203 * <p> 204 * Note that if proxy interfaces with a mix of accessibilities -- for example, 205 * an exported public interface and a non-exported non-public interface -- are 206 * proxied by the same instance, then the proxy class's accessibility is 207 * governed by the least accessible proxy interface. 208 * <p> 209 * Note that it is possible for arbitrary code to obtain access to a proxy class 210 * in an open package with {@link AccessibleObject#setAccessible setAccessible}, 211 * whereas a proxy class in a non-open package is never accessible to 212 * code outside the module of the proxy class. 213 * 214 * <p> 215 * Throughout this specification, a "non-exported package" refers to a package 216 * that is not exported to all modules, and a "non-open package" refers to 217 * a package that is not open to all modules. Specifically, these terms refer to 218 * a package that either is not exported/open by its containing module or is 219 * exported/open in a qualified fashion by its containing module. 220 * 221 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3> 222 * <p> 223 * A dynamic module is a named module generated at runtime. A proxy class 224 * defined in a dynamic module is encapsulated and not accessible to any module. 225 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in 226 * a dynamic module will throw {@code IllegalAccessException}; 227 * {@code Proxy.newProxyInstance} method should be used instead. 228 * 229 * <p> 230 * A dynamic module can read the modules of all of the superinterfaces of a proxy 231 * class and the modules of the types referenced by all public method signatures 232 * of a proxy class. If a superinterface or a referenced type, say {@code T}, 233 * is in a non-exported package, the {@linkplain Module module} of {@code T} is 234 * updated to export the package of {@code T} to the dynamic module. 235 * 236 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3> 237 * 238 * <p>When two or more proxy interfaces contain a method with 239 * the same name and parameter signature, the order of the proxy class's 240 * interfaces becomes significant. When such a <i>duplicate method</i> 241 * is invoked on a proxy instance, the {@code Method} object passed 242 * to the invocation handler will not necessarily be the one whose 243 * declaring class is assignable from the reference type of the interface 244 * that the proxy's method was invoked through. This limitation exists 245 * because the corresponding method implementation in the generated proxy 246 * class cannot determine which interface it was invoked through. 247 * Therefore, when a duplicate method is invoked on a proxy instance, 248 * the {@code Method} object for the method in the foremost interface 249 * that contains the method (either directly or inherited through a 250 * superinterface) in the proxy class's list of interfaces is passed to 251 * the invocation handler's {@code invoke} method, regardless of the 252 * reference type through which the method invocation occurred. 253 * 254 * <p>If a proxy interface contains a method with the same name and 255 * parameter signature as the {@code hashCode}, {@code equals}, 256 * or {@code toString} methods of {@code java.lang.Object}, 257 * when such a method is invoked on a proxy instance, the 258 * {@code Method} object passed to the invocation handler will have 259 * {@code java.lang.Object} as its declaring class. In other words, 260 * the public, non-final methods of {@code java.lang.Object} 261 * logically precede all of the proxy interfaces for the determination of 262 * which {@code Method} object to pass to the invocation handler. 263 * 264 * <p>Note also that when a duplicate method is dispatched to an 265 * invocation handler, the {@code invoke} method may only throw 266 * checked exception types that are assignable to one of the exception 267 * types in the {@code throws} clause of the method in <i>all</i> of 268 * the proxy interfaces that it can be invoked through. If the 269 * {@code invoke} method throws a checked exception that is not 270 * assignable to any of the exception types declared by the method in one 271 * of the proxy interfaces that it can be invoked through, then an 272 * unchecked {@code UndeclaredThrowableException} will be thrown by 273 * the invocation on the proxy instance. This restriction means that not 274 * all of the exception types returned by invoking 275 * {@code getExceptionTypes} on the {@code Method} object 276 * passed to the {@code invoke} method can necessarily be thrown 277 * successfully by the {@code invoke} method. 278 * 279 * @author Peter Jones 280 * @see InvocationHandler 281 * @since 1.3 282 * @revised 9 283 * @spec JPMS 284 */ 285 public class Proxy implements java.io.Serializable { 286 @java.io.Serial 287 private static final long serialVersionUID = -2222568056686623797L; 288 289 /** parameter types of a proxy class constructor */ 290 private static final Class<?>[] constructorParams = 291 { InvocationHandler.class }; 292 293 /** 294 * a cache of proxy constructors with 295 * {@link Constructor#setAccessible(boolean) accessible} flag already set 296 */ 297 private static final ClassLoaderValue<Constructor<?>> proxyCache = 298 new ClassLoaderValue<>(); 299 300 /** 301 * System property to revert to generation of proxy class files for version 1.5 (V49). 302 * Set to "true" to generate v49 class file format. 303 */ 304 private static final boolean PROXY_GENERATOR_V49 = 305 GetBooleanAction.privilegedGetProperty("jdk.proxy.ProxyGenerator.v49"); 306 307 /** 308 * the invocation handler for this proxy instance. 309 * @serial 310 */ 311 protected InvocationHandler h; 312 313 /** 314 * Prohibits instantiation. 315 */ 316 private Proxy() { 317 } 318 319 /** 320 * Constructs a new {@code Proxy} instance from a subclass 321 * (typically, a dynamic proxy class) with the specified value 322 * for its invocation handler. 323 * 324 * @param h the invocation handler for this proxy instance 325 * 326 * @throws NullPointerException if the given invocation handler, {@code h}, 327 * is {@code null}. 328 */ 329 protected Proxy(InvocationHandler h) { 330 Objects.requireNonNull(h); 331 this.h = h; 332 } 333 334 /** 335 * Returns the {@code java.lang.Class} object for a proxy class 336 * given a class loader and an array of interfaces. The proxy class 337 * will be defined by the specified class loader and will implement 338 * all of the supplied interfaces. If any of the given interfaces 339 * is non-public, the proxy class will be non-public. If a proxy class 340 * for the same permutation of interfaces has already been defined by the 341 * class loader, then the existing proxy class will be returned; otherwise, 342 * a proxy class for those interfaces will be generated dynamically 343 * and defined by the class loader. 344 * 345 * @param loader the class loader to define the proxy class 346 * @param interfaces the list of interfaces for the proxy class 347 * to implement 348 * @return a proxy class that is defined in the specified class loader 349 * and that implements the specified interfaces 350 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 351 * restrictions</a> on the parameters are violated 352 * @throws SecurityException if a security manager, <em>s</em>, is present 353 * and any of the following conditions is met: 354 * <ul> 355 * <li> the given {@code loader} is {@code null} and 356 * the caller's class loader is not {@code null} and the 357 * invocation of {@link SecurityManager#checkPermission 358 * s.checkPermission} with 359 * {@code RuntimePermission("getClassLoader")} permission 360 * denies access.</li> 361 * <li> for each proxy interface, {@code intf}, 362 * the caller's class loader is not the same as or an 363 * ancestor of the class loader for {@code intf} and 364 * invocation of {@link SecurityManager#checkPackageAccess 365 * s.checkPackageAccess()} denies access to {@code intf}.</li> 366 * </ul> 367 * @throws NullPointerException if the {@code interfaces} array 368 * argument or any of its elements are {@code null} 369 * 370 * @deprecated Proxy classes generated in a named module are encapsulated 371 * and not accessible to code outside its module. 372 * {@link Constructor#newInstance(Object...) Constructor.newInstance} 373 * will throw {@code IllegalAccessException} when it is called on 374 * an inaccessible proxy class. 375 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)} 376 * to create a proxy instance instead. 377 * 378 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 379 * @revised 9 380 * @spec JPMS 381 */ 382 @Deprecated 383 @CallerSensitive 384 public static Class<?> getProxyClass(ClassLoader loader, 385 Class<?>... interfaces) 386 throws IllegalArgumentException 387 { 388 Class<?> caller = System.getSecurityManager() == null 389 ? null 390 : Reflection.getCallerClass(); 391 392 return getProxyConstructor(caller, loader, interfaces) 393 .getDeclaringClass(); 394 } 395 396 /** 397 * Returns the {@code Constructor} object of a proxy class that takes a 398 * single argument of type {@link InvocationHandler}, given a class loader 399 * and an array of interfaces. The returned constructor will have the 400 * {@link Constructor#setAccessible(boolean) accessible} flag already set. 401 * 402 * @param caller passed from a public-facing @CallerSensitive method if 403 * SecurityManager is set or {@code null} if there's no 404 * SecurityManager 405 * @param loader the class loader to define the proxy class 406 * @param interfaces the list of interfaces for the proxy class 407 * to implement 408 * @return a Constructor of the proxy class taking single 409 * {@code InvocationHandler} parameter 410 */ 411 private static Constructor<?> getProxyConstructor(Class<?> caller, 412 ClassLoader loader, 413 Class<?>... interfaces) 414 { 415 // optimization for single interface 416 if (interfaces.length == 1) { 417 Class<?> intf = interfaces[0]; 418 if (caller != null) { 419 checkProxyAccess(caller, loader, intf); 420 } 421 return proxyCache.sub(intf).computeIfAbsent( 422 loader, 423 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 424 ); 425 } else { 426 // interfaces cloned 427 final Class<?>[] intfsArray = interfaces.clone(); 428 if (caller != null) { 429 checkProxyAccess(caller, loader, intfsArray); 430 } 431 final List<Class<?>> intfs = Arrays.asList(intfsArray); 432 return proxyCache.sub(intfs).computeIfAbsent( 433 loader, 434 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 435 ); 436 } 437 } 438 439 /* 440 * Check permissions required to create a Proxy class. 441 * 442 * To define a proxy class, it performs the access checks as in 443 * Class.forName (VM will invoke ClassLoader.checkPackageAccess): 444 * 1. "getClassLoader" permission check if loader == null 445 * 2. checkPackageAccess on the interfaces it implements 446 * 447 * To get a constructor and new instance of a proxy class, it performs 448 * the package access check on the interfaces it implements 449 * as in Class.getConstructor. 450 * 451 * If an interface is non-public, the proxy class must be defined by 452 * the defining loader of the interface. If the caller's class loader 453 * is not the same as the defining loader of the interface, the VM 454 * will throw IllegalAccessError when the generated proxy class is 455 * being defined. 456 */ 457 private static void checkProxyAccess(Class<?> caller, 458 ClassLoader loader, 459 Class<?> ... interfaces) 460 { 461 SecurityManager sm = System.getSecurityManager(); 462 if (sm != null) { 463 ClassLoader ccl = caller.getClassLoader(); 464 if (loader == null && ccl != null) { 465 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 466 } 467 ReflectUtil.checkProxyPackageAccess(ccl, interfaces); 468 } 469 } 470 471 /** 472 * Builder for a proxy class. 473 * 474 * If the module is not specified in this ProxyBuilder constructor, 475 * it will map from the given loader and interfaces to the module 476 * in which the proxy class will be defined. 477 */ 478 private static final class ProxyBuilder { 479 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess(); 480 481 // prefix for all proxy class names 482 private static final String proxyClassNamePrefix = "$Proxy"; 483 484 // next number to use for generation of unique proxy class names 485 private static final AtomicLong nextUniqueNumber = new AtomicLong(); 486 487 // a reverse cache of defined proxy classes 488 private static final ClassLoaderValue<Boolean> reverseProxyCache = 489 new ClassLoaderValue<>(); 490 491 private static Class<?> defineProxyClass(Module m, List<Class<?>> interfaces) { 492 String proxyPkg = null; // package to define proxy class in 493 int accessFlags = Modifier.PUBLIC | Modifier.FINAL; 494 495 /* 496 * Record the package of a non-public proxy interface so that the 497 * proxy class will be defined in the same package. Verify that 498 * all non-public proxy interfaces are in the same package. 499 */ 500 for (Class<?> intf : interfaces) { 501 int flags = intf.getModifiers(); 502 if (!Modifier.isPublic(flags)) { 503 accessFlags = Modifier.FINAL; // non-public, final 504 String pkg = intf.getPackageName(); 505 if (proxyPkg == null) { 506 proxyPkg = pkg; 507 } else if (!pkg.equals(proxyPkg)) { 508 throw new IllegalArgumentException( 509 "non-public interfaces from different packages"); 510 } 511 } 512 } 513 514 if (proxyPkg == null) { 515 // all proxy interfaces are public 516 proxyPkg = m.isNamed() ? PROXY_PACKAGE_PREFIX + "." + m.getName() 517 : PROXY_PACKAGE_PREFIX; 518 } else if (proxyPkg.isEmpty() && m.isNamed()) { 519 throw new IllegalArgumentException( 520 "Unnamed package cannot be added to " + m); 521 } 522 523 if (m.isNamed()) { 524 if (!m.getDescriptor().packages().contains(proxyPkg)) { 525 throw new InternalError(proxyPkg + " not exist in " + m.getName()); 526 } 527 } 528 529 /* 530 * Choose a name for the proxy class to generate. 531 */ 532 long num = nextUniqueNumber.getAndIncrement(); 533 String proxyName = proxyPkg.isEmpty() 534 ? proxyClassNamePrefix + num 535 : proxyPkg + "." + proxyClassNamePrefix + num; 536 537 ClassLoader loader = getLoader(m); 538 trace(proxyName, m, loader, interfaces); 539 540 /* 541 * Generate the specified proxy class. 542 */ 543 byte[] proxyClassFile = PROXY_GENERATOR_V49 544 ? ProxyGenerator_v49.generateProxyClass(proxyName, interfaces, accessFlags) 545 : ProxyGenerator.generateProxyClass(loader, proxyName, interfaces, accessFlags); 546 try { 547 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile, 548 null, "__dynamic_proxy__"); 549 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE); 550 return pc; 551 } catch (ClassFormatError e) { 552 /* 553 * A ClassFormatError here means that (barring bugs in the 554 * proxy class generation code) there was some other 555 * invalid aspect of the arguments supplied to the proxy 556 * class creation (such as virtual machine limitations 557 * exceeded). 558 */ 559 throw new IllegalArgumentException(e.toString()); 560 } 561 } 562 563 /** 564 * Test if given class is a class defined by 565 * {@link #defineProxyClass(Module, List)} 566 */ 567 static boolean isProxyClass(Class<?> c) { 568 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()), 569 Boolean.TRUE); 570 } 571 572 private static boolean isExportedType(Class<?> c) { 573 String pn = c.getPackageName(); 574 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn); 575 } 576 577 private static boolean isPackagePrivateType(Class<?> c) { 578 return !Modifier.isPublic(c.getModifiers()); 579 } 580 581 private static String toDetails(Class<?> c) { 582 String access = "unknown"; 583 if (isExportedType(c)) { 584 access = "exported"; 585 } else if (isPackagePrivateType(c)) { 586 access = "package-private"; 587 } else { 588 access = "module-private"; 589 } 590 ClassLoader ld = c.getClassLoader(); 591 return String.format(" %s/%s %s loader %s", 592 c.getModule().getName(), c.getName(), access, ld); 593 } 594 595 static void trace(String cn, 596 Module module, 597 ClassLoader loader, 598 List<Class<?>> interfaces) { 599 if (isDebug()) { 600 System.err.format("PROXY: %s/%s defined by %s%n", 601 module.getName(), cn, loader); 602 } 603 if (isDebug("debug")) { 604 interfaces.forEach(c -> System.out.println(toDetails(c))); 605 } 606 } 607 608 private static final String DEBUG = 609 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", ""); 610 611 private static boolean isDebug() { 612 return !DEBUG.isEmpty(); 613 } 614 private static boolean isDebug(String flag) { 615 return DEBUG.equals(flag); 616 } 617 618 // ProxyBuilder instance members start here.... 619 620 private final List<Class<?>> interfaces; 621 private final Module module; 622 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) { 623 if (!VM.isModuleSystemInited()) { 624 throw new InternalError("Proxy is not supported until " 625 + "module system is fully initialized"); 626 } 627 if (interfaces.size() > 65535) { 628 throw new IllegalArgumentException("interface limit exceeded: " 629 + interfaces.size()); 630 } 631 632 Set<Class<?>> refTypes = referencedTypes(loader, interfaces); 633 634 // IAE if violates any restrictions specified in newProxyInstance 635 validateProxyInterfaces(loader, interfaces, refTypes); 636 637 this.interfaces = interfaces; 638 this.module = mapToModule(loader, interfaces, refTypes); 639 assert getLoader(module) == loader; 640 } 641 642 ProxyBuilder(ClassLoader loader, Class<?> intf) { 643 this(loader, Collections.singletonList(intf)); 644 } 645 646 /** 647 * Generate a proxy class and return its proxy Constructor with 648 * accessible flag already set. If the target module does not have access 649 * to any interface types, IllegalAccessError will be thrown by the VM 650 * at defineClass time. 651 * 652 * Must call the checkProxyAccess method to perform permission checks 653 * before calling this. 654 */ 655 Constructor<?> build() { 656 Class<?> proxyClass = defineProxyClass(module, interfaces); 657 final Constructor<?> cons; 658 try { 659 cons = proxyClass.getConstructor(constructorParams); 660 } catch (NoSuchMethodException e) { 661 throw new InternalError(e.toString(), e); 662 } 663 AccessController.doPrivileged(new PrivilegedAction<Void>() { 664 public Void run() { 665 cons.setAccessible(true); 666 return null; 667 } 668 }); 669 return cons; 670 } 671 672 /** 673 * Validate the given proxy interfaces and the given referenced types 674 * are visible to the defining loader. 675 * 676 * @throws IllegalArgumentException if it violates the restrictions 677 * specified in {@link Proxy#newProxyInstance} 678 */ 679 private static void validateProxyInterfaces(ClassLoader loader, 680 List<Class<?>> interfaces, 681 Set<Class<?>> refTypes) 682 { 683 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size()); 684 for (Class<?> intf : interfaces) { 685 /* 686 * Verify that the class loader resolves the name of this 687 * interface to the same Class object. 688 */ 689 ensureVisible(loader, intf); 690 691 /* 692 * Verify that the Class object actually represents an 693 * interface. 694 */ 695 if (!intf.isInterface()) { 696 throw new IllegalArgumentException(intf.getName() + " is not an interface"); 697 } 698 699 /* 700 * Verify that this interface is not a duplicate. 701 */ 702 if (interfaceSet.put(intf, Boolean.TRUE) != null) { 703 throw new IllegalArgumentException("repeated interface: " + intf.getName()); 704 } 705 } 706 707 for (Class<?> type : refTypes) { 708 ensureVisible(loader, type); 709 } 710 } 711 712 /* 713 * Returns all types referenced by all public non-static method signatures of 714 * the proxy interfaces 715 */ 716 private static Set<Class<?>> referencedTypes(ClassLoader loader, 717 List<Class<?>> interfaces) { 718 var types = new HashSet<Class<?>>(); 719 for (var intf : interfaces) { 720 for (Method m : intf.getMethods()) { 721 if (!Modifier.isStatic(m.getModifiers())) { 722 addElementType(types, m.getReturnType()); 723 addElementTypes(types, m.getSharedParameterTypes()); 724 addElementTypes(types, m.getSharedExceptionTypes()); 725 } 726 } 727 } 728 return types; 729 } 730 731 private static void addElementTypes(HashSet<Class<?>> types, 732 Class<?> ... classes) { 733 for (var cls : classes) { 734 addElementType(types, cls); 735 } 736 } 737 738 private static void addElementType(HashSet<Class<?>> types, 739 Class<?> cls) { 740 var type = getElementType(cls); 741 if (!type.isPrimitive()) { 742 types.add(type); 743 } 744 } 745 746 /** 747 * Returns the module that the generated proxy class belongs to. 748 * 749 * If all proxy interfaces are public and in exported packages, 750 * then the proxy class is in unnamed module. 751 * 752 * If any of proxy interface is package-private, then the proxy class 753 * is in the same module of the package-private interface. 754 * 755 * If all proxy interfaces are public and at least one in a non-exported 756 * package, then the proxy class is in a dynamic module in a 757 * non-exported package. Reads edge and qualified exports are added 758 * for dynamic module to access. 759 */ 760 private static Module mapToModule(ClassLoader loader, 761 List<Class<?>> interfaces, 762 Set<Class<?>> refTypes) { 763 Map<Class<?>, Module> modulePrivateTypes = new HashMap<>(); 764 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>(); 765 for (Class<?> intf : interfaces) { 766 Module m = intf.getModule(); 767 if (Modifier.isPublic(intf.getModifiers())) { 768 // module-private types 769 if (!m.isExported(intf.getPackageName())) { 770 modulePrivateTypes.put(intf, m); 771 } 772 } else { 773 packagePrivateTypes.put(intf, m); 774 } 775 } 776 777 // all proxy interfaces are public and exported, the proxy class 778 // is in unnamed module. Such proxy class is accessible to 779 // any unnamed module and named module that can read unnamed module 780 if (packagePrivateTypes.isEmpty() && modulePrivateTypes.isEmpty()) { 781 return loader != null ? loader.getUnnamedModule() 782 : BootLoader.getUnnamedModule(); 783 } 784 785 if (packagePrivateTypes.size() > 0) { 786 // all package-private types must be in the same runtime package 787 // i.e. same package name and same module (named or unnamed) 788 // 789 // Configuration will fail if M1 and in M2 defined by the same loader 790 // and both have the same package p (so no need to check class loader) 791 if (packagePrivateTypes.size() > 1 && 792 (packagePrivateTypes.keySet().stream() // more than one package 793 .map(Class::getPackageName).distinct().count() > 1 || 794 packagePrivateTypes.values().stream() // or more than one module 795 .distinct().count() > 1)) { 796 throw new IllegalArgumentException( 797 "non-public interfaces from different packages"); 798 } 799 800 // all package-private types are in the same module (named or unnamed) 801 Module target = null; 802 for (Module m : packagePrivateTypes.values()) { 803 if (getLoader(m) != loader) { 804 // the specified loader is not the same class loader 805 // of the non-public interface 806 throw new IllegalArgumentException( 807 "non-public interface is not defined by the given loader"); 808 } 809 target = m; 810 } 811 812 // validate if the target module can access all other interfaces 813 for (Class<?> intf : interfaces) { 814 Module m = intf.getModule(); 815 if (m == target) continue; 816 817 if (!target.canRead(m) || !m.isExported(intf.getPackageName(), target)) { 818 throw new IllegalArgumentException(target + " can't access " + intf.getName()); 819 } 820 } 821 822 // return the module of the package-private interface 823 return target; 824 } 825 826 // All proxy interfaces are public and at least one in a non-exported 827 // package. So maps to a dynamic proxy module and add reads edge 828 // and qualified exports, if necessary 829 Module target = getDynamicModule(loader); 830 831 // set up proxy class access to proxy interfaces and types 832 // referenced in the method signature 833 Set<Class<?>> types = new HashSet<>(interfaces); 834 types.addAll(refTypes); 835 for (Class<?> c : types) { 836 ensureAccess(target, c); 837 } 838 return target; 839 } 840 841 /* 842 * Ensure the given module can access the given class. 843 */ 844 private static void ensureAccess(Module target, Class<?> c) { 845 Module m = c.getModule(); 846 // add read edge and qualified export for the target module to access 847 if (!target.canRead(m)) { 848 Modules.addReads(target, m); 849 } 850 String pn = c.getPackageName(); 851 if (!m.isExported(pn, target)) { 852 Modules.addExports(m, pn, target); 853 } 854 } 855 856 /* 857 * Ensure the given class is visible to the class loader. 858 */ 859 private static void ensureVisible(ClassLoader ld, Class<?> c) { 860 Class<?> type = null; 861 try { 862 type = Class.forName(c.getName(), false, ld); 863 } catch (ClassNotFoundException e) { 864 } 865 if (type != c) { 866 throw new IllegalArgumentException(c.getName() + 867 " referenced from a method is not visible from class loader"); 868 } 869 } 870 871 private static Class<?> getElementType(Class<?> type) { 872 Class<?> e = type; 873 while (e.isArray()) { 874 e = e.getComponentType(); 875 } 876 return e; 877 } 878 879 private static final ClassLoaderValue<Module> dynProxyModules = 880 new ClassLoaderValue<>(); 881 private static final AtomicInteger counter = new AtomicInteger(); 882 883 /* 884 * Define a dynamic module for the generated proxy classes in 885 * a non-exported package named com.sun.proxy.$MODULE. 886 * 887 * Each class loader will have one dynamic module. 888 */ 889 private static Module getDynamicModule(ClassLoader loader) { 890 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> { 891 // create a dynamic module and setup module access 892 String mn = "jdk.proxy" + counter.incrementAndGet(); 893 String pn = PROXY_PACKAGE_PREFIX + "." + mn; 894 ModuleDescriptor descriptor = 895 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC)) 896 .packages(Set.of(pn)) 897 .build(); 898 Module m = Modules.defineModule(ld, descriptor, null); 899 Modules.addReads(m, Proxy.class.getModule()); 900 // java.base to create proxy instance 901 Modules.addExports(m, pn, Object.class.getModule()); 902 return m; 903 }); 904 } 905 } 906 907 /** 908 * Returns a proxy instance for the specified interfaces 909 * that dispatches method invocations to the specified invocation 910 * handler. 911 * <p> 912 * <a id="restrictions">{@code IllegalArgumentException} will be thrown 913 * if any of the following restrictions is violated:</a> 914 * <ul> 915 * <li>All of {@code Class} objects in the given {@code interfaces} array 916 * must represent interfaces, not classes or primitive types. 917 * 918 * <li>No two elements in the {@code interfaces} array may 919 * refer to identical {@code Class} objects. 920 * 921 * <li>All of the interface types must be visible by name through the 922 * specified class loader. In other words, for class loader 923 * {@code cl} and every interface {@code i}, the following 924 * expression must be true:<p> 925 * {@code Class.forName(i.getName(), false, cl) == i} 926 * 927 * <li>All of the types referenced by all 928 * public method signatures of the specified interfaces 929 * and those inherited by their superinterfaces 930 * must be visible by name through the specified class loader. 931 * 932 * <li>All non-public interfaces must be in the same package 933 * and module, defined by the specified class loader and 934 * the module of the non-public interfaces can access all of 935 * the interface types; otherwise, it would not be possible for 936 * the proxy class to implement all of the interfaces, 937 * regardless of what package it is defined in. 938 * 939 * <li>For any set of member methods of the specified interfaces 940 * that have the same signature: 941 * <ul> 942 * <li>If the return type of any of the methods is a primitive 943 * type or void, then all of the methods must have that same 944 * return type. 945 * <li>Otherwise, one of the methods must have a return type that 946 * is assignable to all of the return types of the rest of the 947 * methods. 948 * </ul> 949 * 950 * <li>The resulting proxy class must not exceed any limits imposed 951 * on classes by the virtual machine. For example, the VM may limit 952 * the number of interfaces that a class may implement to 65535; in 953 * that case, the size of the {@code interfaces} array must not 954 * exceed 65535. 955 * </ul> 956 * 957 * <p>Note that the order of the specified proxy interfaces is 958 * significant: two requests for a proxy class with the same combination 959 * of interfaces but in a different order will result in two distinct 960 * proxy classes. 961 * 962 * @param loader the class loader to define the proxy class 963 * @param interfaces the list of interfaces for the proxy class 964 * to implement 965 * @param h the invocation handler to dispatch method invocations to 966 * @return a proxy instance with the specified invocation handler of a 967 * proxy class that is defined by the specified class loader 968 * and that implements the specified interfaces 969 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 970 * restrictions</a> on the parameters are violated 971 * @throws SecurityException if a security manager, <em>s</em>, is present 972 * and any of the following conditions is met: 973 * <ul> 974 * <li> the given {@code loader} is {@code null} and 975 * the caller's class loader is not {@code null} and the 976 * invocation of {@link SecurityManager#checkPermission 977 * s.checkPermission} with 978 * {@code RuntimePermission("getClassLoader")} permission 979 * denies access;</li> 980 * <li> for each proxy interface, {@code intf}, 981 * the caller's class loader is not the same as or an 982 * ancestor of the class loader for {@code intf} and 983 * invocation of {@link SecurityManager#checkPackageAccess 984 * s.checkPackageAccess()} denies access to {@code intf};</li> 985 * <li> any of the given proxy interfaces is non-public and the 986 * caller class is not in the same {@linkplain Package runtime package} 987 * as the non-public interface and the invocation of 988 * {@link SecurityManager#checkPermission s.checkPermission} with 989 * {@code ReflectPermission("newProxyInPackage.{package name}")} 990 * permission denies access.</li> 991 * </ul> 992 * @throws NullPointerException if the {@code interfaces} array 993 * argument or any of its elements are {@code null}, or 994 * if the invocation handler, {@code h}, is 995 * {@code null} 996 * 997 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 998 * @revised 9 999 * @spec JPMS 1000 */ 1001 @CallerSensitive 1002 public static Object newProxyInstance(ClassLoader loader, 1003 Class<?>[] interfaces, 1004 InvocationHandler h) { 1005 Objects.requireNonNull(h); 1006 1007 final Class<?> caller = System.getSecurityManager() == null 1008 ? null 1009 : Reflection.getCallerClass(); 1010 1011 /* 1012 * Look up or generate the designated proxy class and its constructor. 1013 */ 1014 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces); 1015 1016 return newProxyInstance(caller, cons, h); 1017 } 1018 1019 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager 1020 Constructor<?> cons, 1021 InvocationHandler h) { 1022 /* 1023 * Invoke its constructor with the designated invocation handler. 1024 */ 1025 try { 1026 if (caller != null) { 1027 checkNewProxyPermission(caller, cons.getDeclaringClass()); 1028 } 1029 1030 return cons.newInstance(new Object[]{h}); 1031 } catch (IllegalAccessException | InstantiationException e) { 1032 throw new InternalError(e.toString(), e); 1033 } catch (InvocationTargetException e) { 1034 Throwable t = e.getCause(); 1035 if (t instanceof RuntimeException) { 1036 throw (RuntimeException) t; 1037 } else { 1038 throw new InternalError(t.toString(), t); 1039 } 1040 } 1041 } 1042 1043 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) { 1044 SecurityManager sm = System.getSecurityManager(); 1045 if (sm != null) { 1046 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) { 1047 ClassLoader ccl = caller.getClassLoader(); 1048 ClassLoader pcl = proxyClass.getClassLoader(); 1049 1050 // do permission check if the caller is in a different runtime package 1051 // of the proxy class 1052 String pkg = proxyClass.getPackageName(); 1053 String callerPkg = caller.getPackageName(); 1054 1055 if (pcl != ccl || !pkg.equals(callerPkg)) { 1056 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg)); 1057 } 1058 } 1059 } 1060 } 1061 1062 /** 1063 * Returns the class loader for the given module. 1064 */ 1065 private static ClassLoader getLoader(Module m) { 1066 PrivilegedAction<ClassLoader> pa = m::getClassLoader; 1067 return AccessController.doPrivileged(pa); 1068 } 1069 1070 /** 1071 * Returns true if the given class is a proxy class. 1072 * 1073 * @implNote The reliability of this method is important for the ability 1074 * to use it to make security decisions, so its implementation should 1075 * not just test if the class in question extends {@code Proxy}. 1076 * 1077 * @param cl the class to test 1078 * @return {@code true} if the class is a proxy class and 1079 * {@code false} otherwise 1080 * @throws NullPointerException if {@code cl} is {@code null} 1081 * 1082 * @revised 9 1083 * @spec JPMS 1084 */ 1085 public static boolean isProxyClass(Class<?> cl) { 1086 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl); 1087 } 1088 1089 /** 1090 * Returns the invocation handler for the specified proxy instance. 1091 * 1092 * @param proxy the proxy instance to return the invocation handler for 1093 * @return the invocation handler for the proxy instance 1094 * @throws IllegalArgumentException if the argument is not a 1095 * proxy instance 1096 * @throws SecurityException if a security manager, <em>s</em>, is present 1097 * and the caller's class loader is not the same as or an 1098 * ancestor of the class loader for the invocation handler 1099 * and invocation of {@link SecurityManager#checkPackageAccess 1100 * s.checkPackageAccess()} denies access to the invocation 1101 * handler's class. 1102 */ 1103 @CallerSensitive 1104 public static InvocationHandler getInvocationHandler(Object proxy) 1105 throws IllegalArgumentException 1106 { 1107 /* 1108 * Verify that the object is actually a proxy instance. 1109 */ 1110 if (!isProxyClass(proxy.getClass())) { 1111 throw new IllegalArgumentException("not a proxy instance"); 1112 } 1113 1114 final Proxy p = (Proxy) proxy; 1115 final InvocationHandler ih = p.h; 1116 if (System.getSecurityManager() != null) { 1117 Class<?> ihClass = ih.getClass(); 1118 Class<?> caller = Reflection.getCallerClass(); 1119 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(), 1120 ihClass.getClassLoader())) 1121 { 1122 ReflectUtil.checkPackageAccess(ihClass); 1123 } 1124 } 1125 1126 return ih; 1127 } 1128 1129 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE; 1130 }