1 /* 2 * Copyright (c) 1997, 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.annotation.Annotation; 29 import java.lang.invoke.MethodHandle; 30 import java.lang.ref.WeakReference; 31 import java.security.AccessController; 32 33 import jdk.internal.access.SharedSecrets; 34 import jdk.internal.misc.VM; 35 import jdk.internal.module.IllegalAccessLogger; 36 import jdk.internal.reflect.CallerSensitive; 37 import jdk.internal.reflect.Reflection; 38 import jdk.internal.reflect.ReflectionFactory; 39 import sun.security.action.GetPropertyAction; 40 import sun.security.util.SecurityConstants; 41 42 /** 43 * The {@code AccessibleObject} class is the base class for {@code Field}, 44 * {@code Method}, and {@code Constructor} objects (known as <em>reflected 45 * objects</em>). It provides the ability to flag a reflected object as 46 * suppressing checks for Java language access control when it is used. This 47 * permits sophisticated applications with sufficient privilege, such as Java 48 * Object Serialization or other persistence mechanisms, to manipulate objects 49 * in a manner that would normally be prohibited. 50 * 51 * <p> Java language access control prevents use of private members outside 52 * their top-level class; package access members outside their package; protected members 53 * outside their package or subclasses; and public members outside their 54 * module unless they are declared in an {@link Module#isExported(String,Module) 55 * exported} package and the user {@link Module#canRead reads} their module. By 56 * default, Java language access control is enforced (with one variation) when 57 * {@code Field}s, {@code Method}s, or {@code Constructor}s are used to get or 58 * set fields, to invoke methods, or to create and initialize new instances of 59 * classes, respectively. Every reflected object checks that the code using it 60 * is in an appropriate class, package, or module. The check when invoked by 61 * <a href="{@docRoot}/../specs/jni/index.html">JNI code</a> with no Java 62 * class on the stack only succeeds if the member and the declaring class are 63 * public, and the class is in a package that is exported to all modules. </p> 64 * 65 * <p> The one variation from Java language access control is that the checks 66 * by reflected objects assume readability. That is, the module containing 67 * the use of a reflected object is assumed to read the module in which 68 * the underlying field, method, or constructor is declared. </p> 69 * 70 * <p> Whether the checks for Java language access control can be suppressed 71 * (and thus, whether access can be enabled) depends on whether the reflected 72 * object corresponds to a member in an exported or open package 73 * (see {@link #setAccessible(boolean)}). </p> 74 * 75 * @jls 6.6 Access Control 76 * @since 1.2 77 * @revised 9 78 * @spec JPMS 79 */ 80 public class AccessibleObject implements AnnotatedElement { 81 static { 82 // AccessibleObject is initialized early in initPhase1 83 SharedSecrets.setJavaLangReflectAccess(new ReflectAccess()); 84 } 85 86 static void checkPermission() { 87 SecurityManager sm = System.getSecurityManager(); 88 if (sm != null) { 89 // SecurityConstants.ACCESS_PERMISSION is used to check 90 // whether a client has sufficient privilege to defeat Java 91 // language access control checks. 92 sm.checkPermission(SecurityConstants.ACCESS_PERMISSION); 93 } 94 } 95 96 /** 97 * Convenience method to set the {@code accessible} flag for an 98 * array of reflected objects with a single security check (for efficiency). 99 * 100 * <p> This method may be used to enable access to all reflected objects in 101 * the array when access to each reflected object can be enabled as 102 * specified by {@link #setAccessible(boolean) setAccessible(boolean)}. </p> 103 * 104 * <p>If there is a security manager, its 105 * {@code checkPermission} method is first called with a 106 * {@code ReflectPermission("suppressAccessChecks")} permission. 107 * 108 * <p>A {@code SecurityException} is also thrown if any of the elements of 109 * the input {@code array} is a {@link java.lang.reflect.Constructor} 110 * object for the class {@code java.lang.Class} and {@code flag} is true. 111 * 112 * @param array the array of AccessibleObjects 113 * @param flag the new value for the {@code accessible} flag 114 * in each object 115 * @throws InaccessibleObjectException if access cannot be enabled for all 116 * objects in the array 117 * @throws SecurityException if the request is denied by the security manager 118 * or an element in the array is a constructor for {@code 119 * java.lang.Class} 120 * @see SecurityManager#checkPermission 121 * @see ReflectPermission 122 * @revised 9 123 * @spec JPMS 124 */ 125 @CallerSensitive 126 public static void setAccessible(AccessibleObject[] array, boolean flag) { 127 checkPermission(); 128 if (flag) { 129 Class<?> caller = Reflection.getCallerClass(); 130 array = array.clone(); 131 for (AccessibleObject ao : array) { 132 ao.checkCanSetAccessible(caller); 133 } 134 } 135 for (AccessibleObject ao : array) { 136 ao.setAccessible0(flag); 137 } 138 } 139 140 /** 141 * Set the {@code accessible} flag for this reflected object to 142 * the indicated boolean value. A value of {@code true} indicates that 143 * the reflected object should suppress checks for Java language access 144 * control when it is used. A value of {@code false} indicates that 145 * the reflected object should enforce checks for Java language access 146 * control when it is used, with the variation noted in the class description. 147 * 148 * <p> This method may be used by a caller in class {@code C} to enable 149 * access to a {@link Member member} of {@link Member#getDeclaringClass() 150 * declaring class} {@code D} if any of the following hold: </p> 151 * 152 * <ul> 153 * <li> {@code C} and {@code D} are in the same module. </li> 154 * 155 * <li> The member is {@code public} and {@code D} is {@code public} in 156 * a package that the module containing {@code D} {@link 157 * Module#isExported(String,Module) exports} to at least the module 158 * containing {@code C}. </li> 159 * 160 * <li> The member is {@code protected} {@code static}, {@code D} is 161 * {@code public} in a package that the module containing {@code D} 162 * exports to at least the module containing {@code C}, and {@code C} 163 * is a subclass of {@code D}. </li> 164 * 165 * <li> {@code D} is in a package that the module containing {@code D} 166 * {@link Module#isOpen(String,Module) opens} to at least the module 167 * containing {@code C}. 168 * All packages in unnamed and open modules are open to all modules and 169 * so this method always succeeds when {@code D} is in an unnamed or 170 * open module. </li> 171 * </ul> 172 * 173 * <p> This method cannot be used to enable access to private members, 174 * members with default (package) access, protected instance members, or 175 * protected constructors when the declaring class is in a different module 176 * to the caller and the package containing the declaring class is not open 177 * to the caller's module. </p> 178 * 179 * <p> If there is a security manager, its 180 * {@code checkPermission} method is first called with a 181 * {@code ReflectPermission("suppressAccessChecks")} permission. 182 * 183 * @param flag the new value for the {@code accessible} flag 184 * @throws InaccessibleObjectException if access cannot be enabled 185 * @throws SecurityException if the request is denied by the security manager 186 * @see #trySetAccessible 187 * @see java.lang.invoke.MethodHandles#privateLookupIn 188 * @revised 9 189 * @spec JPMS 190 */ 191 @CallerSensitive // overrides in Method/Field/Constructor are @CS 192 public void setAccessible(boolean flag) { 193 AccessibleObject.checkPermission(); 194 setAccessible0(flag); 195 } 196 197 /** 198 * Sets the accessible flag and returns the new value 199 */ 200 boolean setAccessible0(boolean flag) { 201 this.override = flag; 202 return flag; 203 } 204 205 /** 206 * Set the {@code accessible} flag for this reflected object to {@code true} 207 * if possible. This method sets the {@code accessible} flag, as if by 208 * invoking {@link #setAccessible(boolean) setAccessible(true)}, and returns 209 * the possibly-updated value for the {@code accessible} flag. If access 210 * cannot be enabled, i.e. the checks or Java language access control cannot 211 * be suppressed, this method returns {@code false} (as opposed to {@code 212 * setAccessible(true)} throwing {@code InaccessibleObjectException} when 213 * it fails). 214 * 215 * <p> This method is a no-op if the {@code accessible} flag for 216 * this reflected object is {@code true}. 217 * 218 * <p> For example, a caller can invoke {@code trySetAccessible} 219 * on a {@code Method} object for a private instance method 220 * {@code p.T::privateMethod} to suppress the checks for Java language access 221 * control when the {@code Method} is invoked. 222 * If {@code p.T} class is in a different module to the caller and 223 * package {@code p} is open to at least the caller's module, 224 * the code below successfully sets the {@code accessible} flag 225 * to {@code true}. 226 * 227 * <pre> 228 * {@code 229 * p.T obj = ....; // instance of p.T 230 * : 231 * Method m = p.T.class.getDeclaredMethod("privateMethod"); 232 * if (m.trySetAccessible()) { 233 * m.invoke(obj); 234 * } else { 235 * // package p is not opened to the caller to access private member of T 236 * ... 237 * } 238 * }</pre> 239 * 240 * <p> If there is a security manager, its {@code checkPermission} method 241 * is first called with a {@code ReflectPermission("suppressAccessChecks")} 242 * permission. </p> 243 * 244 * @return {@code true} if the {@code accessible} flag is set to {@code true}; 245 * {@code false} if access cannot be enabled. 246 * @throws SecurityException if the request is denied by the security manager 247 * 248 * @since 9 249 * @spec JPMS 250 * @see java.lang.invoke.MethodHandles#privateLookupIn 251 */ 252 @CallerSensitive 253 public final boolean trySetAccessible() { 254 AccessibleObject.checkPermission(); 255 256 if (override == true) return true; 257 258 // if it's not a Constructor, Method, Field then no access check 259 if (!Member.class.isInstance(this)) { 260 return setAccessible0(true); 261 } 262 263 // does not allow to suppress access check for Class's constructor 264 Class<?> declaringClass = ((Member) this).getDeclaringClass(); 265 if (declaringClass == Class.class && this instanceof Constructor) { 266 return false; 267 } 268 269 if (checkCanSetAccessible(Reflection.getCallerClass(), 270 declaringClass, 271 false)) { 272 return setAccessible0(true); 273 } else { 274 return false; 275 } 276 } 277 278 279 /** 280 * If the given AccessibleObject is a {@code Constructor}, {@code Method} 281 * or {@code Field} then checks that its declaring class is in a package 282 * that can be accessed by the given caller of setAccessible. 283 */ 284 void checkCanSetAccessible(Class<?> caller) { 285 // do nothing, needs to be overridden by Constructor, Method, Field 286 } 287 288 final void checkCanSetAccessible(Class<?> caller, Class<?> declaringClass) { 289 checkCanSetAccessible(caller, declaringClass, true); 290 } 291 292 private boolean checkCanSetAccessible(Class<?> caller, 293 Class<?> declaringClass, 294 boolean throwExceptionIfDenied) { 295 if (caller == MethodHandle.class) { 296 throw new IllegalCallerException(); // should not happen 297 } 298 299 Module callerModule = caller.getModule(); 300 Module declaringModule = declaringClass.getModule(); 301 302 if (callerModule == declaringModule) return true; 303 if (callerModule == Object.class.getModule()) return true; 304 if (!declaringModule.isNamed()) return true; 305 306 String pn = declaringClass.getPackageName(); 307 int modifiers; 308 if (this instanceof Executable) { 309 modifiers = ((Executable) this).getModifiers(); 310 } else { 311 modifiers = ((Field) this).getModifiers(); 312 } 313 314 // class is public and package is exported to caller 315 boolean isClassPublic = Modifier.isPublic(declaringClass.getModifiers()); 316 if (isClassPublic && declaringModule.isExported(pn, callerModule)) { 317 // member is public 318 if (Modifier.isPublic(modifiers)) { 319 logIfExportedForIllegalAccess(caller, declaringClass); 320 return true; 321 } 322 323 // member is protected-static 324 if (Modifier.isProtected(modifiers) 325 && Modifier.isStatic(modifiers) 326 && isSubclassOf(caller, declaringClass)) { 327 logIfExportedForIllegalAccess(caller, declaringClass); 328 return true; 329 } 330 } 331 332 // package is open to caller 333 if (declaringModule.isOpen(pn, callerModule)) { 334 logIfOpenedForIllegalAccess(caller, declaringClass); 335 return true; 336 } 337 338 if (throwExceptionIfDenied) { 339 // not accessible 340 String msg = "Unable to make "; 341 if (this instanceof Field) 342 msg += "field "; 343 msg += this + " accessible: " + declaringModule + " does not \""; 344 if (isClassPublic && Modifier.isPublic(modifiers)) 345 msg += "exports"; 346 else 347 msg += "opens"; 348 msg += " " + pn + "\" to " + callerModule; 349 InaccessibleObjectException e = new InaccessibleObjectException(msg); 350 if (printStackTraceWhenAccessFails()) { 351 e.printStackTrace(System.err); 352 } 353 throw e; 354 } 355 return false; 356 } 357 358 private boolean isSubclassOf(Class<?> queryClass, Class<?> ofClass) { 359 while (queryClass != null) { 360 if (queryClass == ofClass) { 361 return true; 362 } 363 queryClass = queryClass.getSuperclass(); 364 } 365 return false; 366 } 367 368 private void logIfOpenedForIllegalAccess(Class<?> caller, Class<?> declaringClass) { 369 Module callerModule = caller.getModule(); 370 Module targetModule = declaringClass.getModule(); 371 // callerModule is null during early startup 372 if (callerModule != null && !callerModule.isNamed() && targetModule.isNamed()) { 373 IllegalAccessLogger logger = IllegalAccessLogger.illegalAccessLogger(); 374 if (logger != null) { 375 logger.logIfOpenedForIllegalAccess(caller, declaringClass, this::toShortString); 376 } 377 } 378 } 379 380 private void logIfExportedForIllegalAccess(Class<?> caller, Class<?> declaringClass) { 381 Module callerModule = caller.getModule(); 382 Module targetModule = declaringClass.getModule(); 383 // callerModule is null during early startup 384 if (callerModule != null && !callerModule.isNamed() && targetModule.isNamed()) { 385 IllegalAccessLogger logger = IllegalAccessLogger.illegalAccessLogger(); 386 if (logger != null) { 387 logger.logIfExportedForIllegalAccess(caller, declaringClass, this::toShortString); 388 } 389 } 390 } 391 392 /** 393 * Returns a short descriptive string to describe this object in log messages. 394 */ 395 String toShortString() { 396 return toString(); 397 } 398 399 /** 400 * Get the value of the {@code accessible} flag for this reflected object. 401 * 402 * @return the value of the object's {@code accessible} flag 403 * 404 * @deprecated 405 * This method is deprecated because its name hints that it checks 406 * if the reflected object is accessible when it actually indicates 407 * if the checks for Java language access control are suppressed. 408 * This method may return {@code false} on a reflected object that is 409 * accessible to the caller. To test if this reflected object is accessible, 410 * it should use {@link #canAccess(Object)}. 411 * 412 * @revised 9 413 * @spec JPMS 414 */ 415 @Deprecated(since="9") 416 public boolean isAccessible() { 417 return override; 418 } 419 420 /** 421 * Test if the caller can access this reflected object. If this reflected 422 * object corresponds to an instance method or field then this method tests 423 * if the caller can access the given {@code obj} with the reflected object. 424 * For instance methods or fields then the {@code obj} argument must be an 425 * instance of the {@link Member#getDeclaringClass() declaring class}. For 426 * static members and constructors then {@code obj} must be {@code null}. 427 * 428 * <p> This method returns {@code true} if the {@code accessible} flag 429 * is set to {@code true}, i.e. the checks for Java language access control 430 * are suppressed, or if the caller can access the member as 431 * specified in <cite>The Java™ Language Specification</cite>, 432 * with the variation noted in the class description. </p> 433 * 434 * @param obj an instance object of the declaring class of this reflected 435 * object if it is an instance method or field 436 * 437 * @return {@code true} if the caller can access this reflected object. 438 * 439 * @throws IllegalArgumentException 440 * <ul> 441 * <li> if this reflected object is a static member or constructor and 442 * the given {@code obj} is non-{@code null}, or </li> 443 * <li> if this reflected object is an instance method or field 444 * and the given {@code obj} is {@code null} or of type 445 * that is not a subclass of the {@link Member#getDeclaringClass() 446 * declaring class} of the member.</li> 447 * </ul> 448 * 449 * @since 9 450 * @spec JPMS 451 * @jls 6.6 Access Control 452 * @see #trySetAccessible 453 * @see #setAccessible(boolean) 454 */ 455 @CallerSensitive 456 public final boolean canAccess(Object obj) { 457 if (!Member.class.isInstance(this)) { 458 return override; 459 } 460 461 Class<?> declaringClass = ((Member) this).getDeclaringClass(); 462 int modifiers = ((Member) this).getModifiers(); 463 if (!Modifier.isStatic(modifiers) && 464 (this instanceof Method || this instanceof Field)) { 465 if (obj == null) { 466 throw new IllegalArgumentException("null object for " + this); 467 } 468 // if this object is an instance member, the given object 469 // must be a subclass of the declaring class of this reflected object 470 if (!declaringClass.isAssignableFrom(obj.getClass())) { 471 throw new IllegalArgumentException("object is not an instance of " 472 + declaringClass.getName()); 473 } 474 } else if (obj != null) { 475 throw new IllegalArgumentException("non-null object for " + this); 476 } 477 478 // access check is suppressed 479 if (override) return true; 480 481 Class<?> caller = Reflection.getCallerClass(); 482 Class<?> targetClass; 483 if (this instanceof Constructor) { 484 targetClass = declaringClass; 485 } else { 486 targetClass = Modifier.isStatic(modifiers) ? null : obj.getClass(); 487 } 488 return verifyAccess(caller, declaringClass, targetClass, modifiers); 489 } 490 491 /** 492 * Constructor: only used by the Java Virtual Machine. 493 */ 494 protected AccessibleObject() {} 495 496 // Indicates whether language-level access checks are overridden 497 // by this object. Initializes to "false". This field is used by 498 // Field, Method, and Constructor. 499 // 500 // NOTE: for security purposes, this field must not be visible 501 // outside this package. 502 boolean override; 503 504 // Reflection factory used by subclasses for creating field, 505 // method, and constructor accessors. Note that this is called 506 // very early in the bootstrapping process. 507 static final ReflectionFactory reflectionFactory = 508 AccessController.doPrivileged( 509 new ReflectionFactory.GetReflectionFactoryAction()); 510 511 /** 512 * @throws NullPointerException {@inheritDoc} 513 * @since 1.5 514 */ 515 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 516 throw new AssertionError("All subclasses should override this method"); 517 } 518 519 /** 520 * {@inheritDoc} 521 * @throws NullPointerException {@inheritDoc} 522 * @since 1.5 523 */ 524 @Override 525 public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) { 526 return AnnotatedElement.super.isAnnotationPresent(annotationClass); 527 } 528 529 /** 530 * @throws NullPointerException {@inheritDoc} 531 * @since 1.8 532 */ 533 @Override 534 public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) { 535 throw new AssertionError("All subclasses should override this method"); 536 } 537 538 /** 539 * @since 1.5 540 */ 541 public Annotation[] getAnnotations() { 542 return getDeclaredAnnotations(); 543 } 544 545 /** 546 * @throws NullPointerException {@inheritDoc} 547 * @since 1.8 548 */ 549 @Override 550 public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) { 551 // Only annotations on classes are inherited, for all other 552 // objects getDeclaredAnnotation is the same as 553 // getAnnotation. 554 return getAnnotation(annotationClass); 555 } 556 557 /** 558 * @throws NullPointerException {@inheritDoc} 559 * @since 1.8 560 */ 561 @Override 562 public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) { 563 // Only annotations on classes are inherited, for all other 564 // objects getDeclaredAnnotationsByType is the same as 565 // getAnnotationsByType. 566 return getAnnotationsByType(annotationClass); 567 } 568 569 /** 570 * @since 1.5 571 */ 572 public Annotation[] getDeclaredAnnotations() { 573 throw new AssertionError("All subclasses should override this method"); 574 } 575 576 // Shared access checking logic. 577 578 // For non-public members or members in package-private classes, 579 // it is necessary to perform somewhat expensive access checks. 580 // If the access check succeeds for a given class, it will 581 // always succeed (it is not affected by the granting or revoking 582 // of permissions); we speed up the check in the common case by 583 // remembering the last Class for which the check succeeded. 584 // 585 // The simple access check for Constructor is to see if 586 // the caller has already been seen, verified, and cached. 587 // 588 // A more complicated access check cache is needed for Method and Field 589 // The cache can be either null (empty cache), {caller,targetClass} pair, 590 // or a caller (with targetClass implicitly equal to memberClass). 591 // In the {caller,targetClass} case, the targetClass is always different 592 // from the memberClass. 593 volatile Object accessCheckCache; 594 595 private static class Cache { 596 final WeakReference<Class<?>> callerRef; 597 final WeakReference<Class<?>> targetRef; 598 599 Cache(Class<?> caller, Class<?> target) { 600 this.callerRef = new WeakReference<>(caller); 601 this.targetRef = new WeakReference<>(target); 602 } 603 604 boolean isCacheFor(Class<?> caller, Class<?> refc) { 605 return callerRef.get() == caller && targetRef.get() == refc; 606 } 607 608 static Object protectedMemberCallerCache(Class<?> caller, Class<?> refc) { 609 return new Cache(caller, refc); 610 } 611 } 612 613 /* 614 * Returns true if the previous access check was verified for the 615 * given caller accessing a protected member with an instance of 616 * the given targetClass where the target class is different than 617 * the declaring member class. 618 */ 619 private boolean isAccessChecked(Class<?> caller, Class<?> targetClass) { 620 Object cache = accessCheckCache; // read volatile 621 if (cache instanceof Cache) { 622 return ((Cache) cache).isCacheFor(caller, targetClass); 623 } 624 return false; 625 } 626 627 /* 628 * Returns true if the previous access check was verified for the 629 * given caller accessing a static member or an instance member of 630 * the target class that is the same as the declaring member class. 631 */ 632 private boolean isAccessChecked(Class<?> caller) { 633 Object cache = accessCheckCache; // read volatile 634 if (cache instanceof WeakReference) { 635 @SuppressWarnings("unchecked") 636 WeakReference<Class<?>> ref = (WeakReference<Class<?>>) cache; 637 return ref.get() == caller; 638 } 639 return false; 640 } 641 642 final void checkAccess(Class<?> caller, Class<?> memberClass, 643 Class<?> targetClass, int modifiers) 644 throws IllegalAccessException 645 { 646 if (!verifyAccess(caller, memberClass, targetClass, modifiers)) { 647 IllegalAccessException e = Reflection.newIllegalAccessException( 648 caller, memberClass, targetClass, modifiers); 649 if (printStackTraceWhenAccessFails()) { 650 e.printStackTrace(System.err); 651 } 652 throw e; 653 } 654 } 655 656 final boolean verifyAccess(Class<?> caller, Class<?> memberClass, 657 Class<?> targetClass, int modifiers) 658 { 659 if (caller == memberClass) { // quick check 660 return true; // ACCESS IS OK 661 } 662 if (targetClass != null // instance member or constructor 663 && Modifier.isProtected(modifiers) 664 && targetClass != memberClass) { 665 if (isAccessChecked(caller, targetClass)) { 666 return true; // ACCESS IS OK 667 } 668 } else if (isAccessChecked(caller)) { 669 // Non-protected case (or targetClass == memberClass or static member). 670 return true; // ACCESS IS OK 671 } 672 673 // If no return, fall through to the slow path. 674 return slowVerifyAccess(caller, memberClass, targetClass, modifiers); 675 } 676 677 // Keep all this slow stuff out of line: 678 private boolean slowVerifyAccess(Class<?> caller, Class<?> memberClass, 679 Class<?> targetClass, int modifiers) 680 { 681 682 if (caller == null) { 683 // No caller frame when a native thread attaches to the VM 684 // only allow access to a public accessible member 685 return Reflection.verifyPublicMemberAccess(memberClass, modifiers); 686 } 687 688 if (!Reflection.verifyMemberAccess(caller, memberClass, targetClass, modifiers)) { 689 // access denied 690 return false; 691 } 692 693 // access okay 694 logIfExportedForIllegalAccess(caller, memberClass); 695 696 // Success: Update the cache. 697 Object cache = (targetClass != null 698 && Modifier.isProtected(modifiers) 699 && targetClass != memberClass) 700 ? Cache.protectedMemberCallerCache(caller, targetClass) 701 : new WeakReference<>(caller); 702 accessCheckCache = cache; // write volatile 703 return true; 704 } 705 706 // true to print a stack trace when access fails 707 private static volatile boolean printStackWhenAccessFails; 708 709 // true if printStack* values are initialized 710 private static volatile boolean printStackPropertiesSet; 711 712 /** 713 * Returns true if a stack trace should be printed when access fails. 714 */ 715 private static boolean printStackTraceWhenAccessFails() { 716 if (!printStackPropertiesSet && VM.initLevel() >= 1) { 717 String s = GetPropertyAction.privilegedGetProperty( 718 "sun.reflect.debugModuleAccessChecks"); 719 if (s != null) { 720 printStackWhenAccessFails = !s.equalsIgnoreCase("false"); 721 } 722 printStackPropertiesSet = true; 723 } 724 return printStackWhenAccessFails; 725 } 726 727 /** 728 * Returns the root AccessibleObject; or null if this object is the root. 729 * 730 * All subclasses override this method. 731 */ 732 AccessibleObject getRoot() { 733 throw new InternalError(); 734 } 735 }