1 /*
2 * Copyright (c) 2001, 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 jdk.internal.reflect;
27
28 import java.io.Externalizable;
29 import java.io.ObjectInputStream;
30 import java.io.ObjectOutputStream;
31 import java.io.ObjectStreamClass;
32 import java.io.OptionalDataException;
33 import java.io.Serializable;
34 import java.lang.invoke.MethodHandle;
35 import java.lang.invoke.MethodHandles;
36 import java.lang.reflect.Field;
37 import java.lang.reflect.Executable;
38 import java.lang.reflect.InvocationTargetException;
39 import java.lang.reflect.Method;
40 import java.lang.reflect.Constructor;
41 import java.lang.reflect.Modifier;
42 import java.security.PrivilegedAction;
43 import java.util.Objects;
44 import java.util.Properties;
45
46 import jdk.internal.access.JavaLangReflectAccess;
47 import jdk.internal.access.SharedSecrets;
48 import jdk.internal.misc.VM;
49 import sun.reflect.misc.ReflectUtil;
50 import sun.security.action.GetPropertyAction;
51 import sun.security.util.SecurityConstants;
52
53 /** <P> The master factory for all reflective objects, both those in
54 java.lang.reflect (Fields, Methods, Constructors) as well as their
55 delegates (FieldAccessors, MethodAccessors, ConstructorAccessors).
56 </P>
57
58 <P> The methods in this class are extremely unsafe and can cause
59 subversion of both the language and the verifier. For this reason,
60 they are all instance methods, and access to the constructor of
61 this factory is guarded by a security check, in similar style to
62 {@link jdk.internal.misc.Unsafe}. </P>
63 */
64
65 public class ReflectionFactory {
66
67 private static boolean initted = false;
68 private static final ReflectionFactory soleInstance = new ReflectionFactory();
69
70
71 /* Method for static class initializer <clinit>, or null */
72 private static volatile Method hasStaticInitializerMethod;
73
74 //
75 // "Inflation" mechanism. Loading bytecodes to implement
76 // Method.invoke() and Constructor.newInstance() currently costs
77 // 3-4x more than an invocation via native code for the first
78 // invocation (though subsequent invocations have been benchmarked
79 // to be over 20x faster). Unfortunately this cost increases
80 // startup time for certain applications that use reflection
81 // intensively (but only once per class) to bootstrap themselves.
82 // To avoid this penalty we reuse the existing JVM entry points
83 // for the first few invocations of Methods and Constructors and
84 // then switch to the bytecode-based implementations.
85 //
86 // Package-private to be accessible to NativeMethodAccessorImpl
87 // and NativeConstructorAccessorImpl
88 private static boolean noInflation = false;
89 private static int inflationThreshold = 15;
90
91 // true if deserialization constructor checking is disabled
92 private static boolean disableSerialConstructorChecks = false;
93
94 private final JavaLangReflectAccess langReflectAccess;
95 private ReflectionFactory() {
96 this.langReflectAccess = SharedSecrets.getJavaLangReflectAccess();
97 }
98
99 /**
100 * A convenience class for acquiring the capability to instantiate
101 * reflective objects. Use this instead of a raw call to {@link
102 * #getReflectionFactory} in order to avoid being limited by the
103 * permissions of your callers.
104 *
105 * <p>An instance of this class can be used as the argument of
106 * <code>AccessController.doPrivileged</code>.
107 */
108 public static final class GetReflectionFactoryAction
109 implements PrivilegedAction<ReflectionFactory> {
110 public ReflectionFactory run() {
111 return getReflectionFactory();
112 }
113 }
114
115 /**
116 * Provides the caller with the capability to instantiate reflective
117 * objects.
118 *
119 * <p> First, if there is a security manager, its
120 * <code>checkPermission</code> method is called with a {@link
121 * java.lang.RuntimePermission} with target
122 * <code>"reflectionFactoryAccess"</code>. This may result in a
123 * security exception.
124 *
125 * <p> The returned <code>ReflectionFactory</code> object should be
126 * carefully guarded by the caller, since it can be used to read and
127 * write private data and invoke private methods, as well as to load
128 * unverified bytecodes. It must never be passed to untrusted code.
129 *
130 * @exception SecurityException if a security manager exists and its
131 * <code>checkPermission</code> method doesn't allow
132 * access to the RuntimePermission "reflectionFactoryAccess". */
133 public static ReflectionFactory getReflectionFactory() {
134 SecurityManager security = System.getSecurityManager();
135 if (security != null) {
136 security.checkPermission(
137 SecurityConstants.REFLECTION_FACTORY_ACCESS_PERMISSION);
138 }
139 return soleInstance;
140 }
141
142 /**
143 * Returns an alternate reflective Method instance for the given method
144 * intended for reflection to invoke, if present.
145 *
146 * A trusted method can define an alternate implementation for a method `foo`
147 * by defining a method named "reflected$foo" that will be invoked
148 * reflectively.
149 */
150 private static Method findMethodForReflection(Method method) {
151 String altName = "reflected$" + method.getName();
152 try {
153 return method.getDeclaringClass()
154 .getDeclaredMethod(altName, method.getParameterTypes());
155 } catch (NoSuchMethodException ex) {
156 return null;
157 }
158 }
159
160 //--------------------------------------------------------------------------
161 //
162 // Routines used by java.lang.reflect
163 //
164 //
165
166 /*
167 * Note: this routine can cause the declaring class for the field
168 * be initialized and therefore must not be called until the
169 * first get/set of this field.
170 * @param field the field
171 * @param override true if caller has overridden accessibility
172 */
173 public FieldAccessor newFieldAccessor(Field field, boolean override) {
174 checkInitted();
175
176 Field root = langReflectAccess.getRoot(field);
177 if (root != null) {
178 // FieldAccessor will use the root unless the modifiers have
179 // been overrridden
180 if (root.getModifiers() == field.getModifiers() || !override) {
181 field = root;
182 }
183 }
184 return UnsafeFieldAccessorFactory.newFieldAccessor(field, override);
185 }
186
187 public MethodAccessor newMethodAccessor(Method method) {
188 checkInitted();
189
190 if (Reflection.isCallerSensitive(method)) {
191 Method altMethod = findMethodForReflection(method);
192 if (altMethod != null) {
193 method = altMethod;
194 }
195 }
196
197 // use the root Method that will not cache caller class
198 Method root = langReflectAccess.getRoot(method);
199 if (root != null) {
200 method = root;
201 }
202
203 if (noInflation && !ReflectUtil.isVMAnonymousClass(method.getDeclaringClass())) {
204 return new MethodAccessorGenerator().
205 generateMethod(method.getDeclaringClass(),
206 method.getName(),
207 method.getParameterTypes(),
208 method.getReturnType(),
209 method.getExceptionTypes(),
210 method.getModifiers());
211 } else {
212 NativeMethodAccessorImpl acc =
213 new NativeMethodAccessorImpl(method);
214 DelegatingMethodAccessorImpl res =
215 new DelegatingMethodAccessorImpl(acc);
216 acc.setParent(res);
217 return res;
218 }
219 }
220
221 public ConstructorAccessor newConstructorAccessor(Constructor<?> c) {
222 checkInitted();
223
224 Class<?> declaringClass = c.getDeclaringClass();
225 if (Modifier.isAbstract(declaringClass.getModifiers())) {
226 return new InstantiationExceptionConstructorAccessorImpl(null);
227 }
228 if (declaringClass == Class.class) {
229 return new InstantiationExceptionConstructorAccessorImpl
230 ("Can not instantiate java.lang.Class");
231 }
232
233 // use the root Constructor that will not cache caller class
234 Constructor<?> root = langReflectAccess.getRoot(c);
235 if (root != null) {
236 c = root;
237 }
238
239 // Bootstrapping issue: since we use Class.newInstance() in
240 // the ConstructorAccessor generation process, we have to
241 // break the cycle here.
242 if (Reflection.isSubclassOf(declaringClass,
243 ConstructorAccessorImpl.class)) {
244 return new BootstrapConstructorAccessorImpl(c);
245 }
246
247 if (noInflation && !ReflectUtil.isVMAnonymousClass(c.getDeclaringClass())) {
248 return new MethodAccessorGenerator().
249 generateConstructor(c.getDeclaringClass(),
250 c.getParameterTypes(),
251 c.getExceptionTypes(),
252 c.getModifiers());
253 } else {
254 NativeConstructorAccessorImpl acc =
255 new NativeConstructorAccessorImpl(c);
256 DelegatingConstructorAccessorImpl res =
257 new DelegatingConstructorAccessorImpl(acc);
258 acc.setParent(res);
259 return res;
260 }
261 }
262
263 //--------------------------------------------------------------------------
264 //
265 // Routines used by java.lang
266 //
267 //
268
269 /** Creates a new java.lang.reflect.Constructor. Access checks as
270 per java.lang.reflect.AccessibleObject are not overridden. */
271 public Constructor<?> newConstructor(Class<?> declaringClass,
272 Class<?>[] parameterTypes,
273 Class<?>[] checkedExceptions,
274 int modifiers,
275 int slot,
276 String signature,
277 byte[] annotations,
278 byte[] parameterAnnotations)
279 {
280 return langReflectAccess.newConstructor(declaringClass,
281 parameterTypes,
282 checkedExceptions,
283 modifiers,
284 slot,
285 signature,
286 annotations,
287 parameterAnnotations);
288 }
289
290 /** Gets the ConstructorAccessor object for a
291 java.lang.reflect.Constructor */
292 public ConstructorAccessor getConstructorAccessor(Constructor<?> c) {
293 return langReflectAccess.getConstructorAccessor(c);
294 }
295
296 /** Sets the ConstructorAccessor object for a
297 java.lang.reflect.Constructor */
298 public void setConstructorAccessor(Constructor<?> c,
299 ConstructorAccessor accessor)
300 {
301 langReflectAccess.setConstructorAccessor(c, accessor);
302 }
303
304 /** Makes a copy of the passed method. The returned method is a
305 "child" of the passed one; see the comments in Method.java for
306 details. */
307 public Method copyMethod(Method arg) {
308 return langReflectAccess.copyMethod(arg);
309 }
310
311 /** Makes a copy of the passed method. The returned method is NOT
312 * a "child" but a "sibling" of the Method in arg. Should only be
313 * used on non-root methods. */
314 public Method leafCopyMethod(Method arg) {
315 return langReflectAccess.leafCopyMethod(arg);
316 }
317
318
319 /** Makes a copy of the passed field. The returned field is a
320 "child" of the passed one; see the comments in Field.java for
321 details. */
322 public Field copyField(Field arg) {
323 return langReflectAccess.copyField(arg);
324 }
325
326 /** Makes a copy of the passed constructor. The returned
327 constructor is a "child" of the passed one; see the comments
328 in Constructor.java for details. */
329 public <T> Constructor<T> copyConstructor(Constructor<T> arg) {
330 return langReflectAccess.copyConstructor(arg);
331 }
332
333 /** Gets the byte[] that encodes TypeAnnotations on an executable.
334 */
335 public byte[] getExecutableTypeAnnotationBytes(Executable ex) {
336 return langReflectAccess.getExecutableTypeAnnotationBytes(ex);
337 }
338
339 public Class<?>[] getExecutableSharedParameterTypes(Executable ex) {
340 return langReflectAccess.getExecutableSharedParameterTypes(ex);
341 }
342
343 public <T> T newInstance(Constructor<T> ctor, Object[] args, Class<?> caller)
344 throws IllegalAccessException, InstantiationException, InvocationTargetException
345 {
346 return langReflectAccess.newInstance(ctor, args, caller);
347 }
348
349 //--------------------------------------------------------------------------
350 //
351 // Routines used by serialization
352 //
353 //
354
355 public final Constructor<?> newConstructorForExternalization(Class<?> cl) {
356 if (!Externalizable.class.isAssignableFrom(cl)) {
357 return null;
358 }
359 try {
360 Constructor<?> cons = cl.getConstructor();
361 cons.setAccessible(true);
362 return cons;
363 } catch (NoSuchMethodException ex) {
364 return null;
365 }
366 }
367
368 public final Constructor<?> newConstructorForSerialization(Class<?> cl,
369 Constructor<?> constructorToCall)
370 {
371 if (constructorToCall.getDeclaringClass() == cl) {
372 constructorToCall.setAccessible(true);
373 return constructorToCall;
374 }
375 return generateConstructor(cl, constructorToCall);
376 }
377
378 /**
379 * Given a class, determines whether its superclass has
380 * any constructors that are accessible from the class.
381 * This is a special purpose method intended to do access
382 * checking for a serializable class and its superclasses
383 * up to, but not including, the first non-serializable
384 * superclass. This also implies that the superclass is
385 * always non-null, because a serializable class must be a
386 * class (not an interface) and Object is not serializable.
387 *
388 * @param cl the class from which access is checked
389 * @return whether the superclass has a constructor accessible from cl
390 */
391 private boolean superHasAccessibleConstructor(Class<?> cl) {
392 Class<?> superCl = cl.getSuperclass();
393 assert Serializable.class.isAssignableFrom(cl);
394 assert superCl != null;
395 if (packageEquals(cl, superCl)) {
396 // accessible if any non-private constructor is found
397 for (Constructor<?> ctor : superCl.getDeclaredConstructors()) {
398 if ((ctor.getModifiers() & Modifier.PRIVATE) == 0) {
399 return true;
400 }
401 }
402 if (Reflection.areNestMates(cl, superCl)) {
403 return true;
404 }
405 return false;
406 } else {
407 // sanity check to ensure the parent is protected or public
408 if ((superCl.getModifiers() & (Modifier.PROTECTED | Modifier.PUBLIC)) == 0) {
409 return false;
410 }
411 // accessible if any constructor is protected or public
412 for (Constructor<?> ctor : superCl.getDeclaredConstructors()) {
413 if ((ctor.getModifiers() & (Modifier.PROTECTED | Modifier.PUBLIC)) != 0) {
414 return true;
415 }
416 }
417 return false;
418 }
419 }
420
421 /**
422 * Returns a constructor that allocates an instance of cl and that then initializes
423 * the instance by calling the no-arg constructor of its first non-serializable
424 * superclass. This is specified in the Serialization Specification, section 3.1,
425 * in step 11 of the deserialization process. If cl is not serializable, returns
426 * cl's no-arg constructor. If no accessible constructor is found, or if the
427 * class hierarchy is somehow malformed (e.g., a serializable class has no
428 * superclass), null is returned.
429 *
430 * @param cl the class for which a constructor is to be found
431 * @return the generated constructor, or null if none is available
432 */
433 public final Constructor<?> newConstructorForSerialization(Class<?> cl) {
434 Class<?> initCl = cl;
435 while (Serializable.class.isAssignableFrom(initCl)) {
436 Class<?> prev = initCl;
437 if ((initCl = initCl.getSuperclass()) == null ||
438 (!disableSerialConstructorChecks && !superHasAccessibleConstructor(prev))) {
439 return null;
440 }
441 }
442 Constructor<?> constructorToCall;
443 try {
444 constructorToCall = initCl.getDeclaredConstructor();
445 int mods = constructorToCall.getModifiers();
446 if ((mods & Modifier.PRIVATE) != 0 ||
447 ((mods & (Modifier.PUBLIC | Modifier.PROTECTED)) == 0 &&
448 !packageEquals(cl, initCl))) {
449 return null;
450 }
451 } catch (NoSuchMethodException ex) {
452 return null;
453 }
454 return generateConstructor(cl, constructorToCall);
455 }
456
457 private final Constructor<?> generateConstructor(Class<?> cl,
458 Constructor<?> constructorToCall) {
459
460
461 ConstructorAccessor acc = new MethodAccessorGenerator().
462 generateSerializationConstructor(cl,
463 constructorToCall.getParameterTypes(),
464 constructorToCall.getExceptionTypes(),
465 constructorToCall.getModifiers(),
466 constructorToCall.getDeclaringClass());
467 Constructor<?> c = newConstructor(constructorToCall.getDeclaringClass(),
468 constructorToCall.getParameterTypes(),
469 constructorToCall.getExceptionTypes(),
470 constructorToCall.getModifiers(),
471 langReflectAccess.
472 getConstructorSlot(constructorToCall),
473 langReflectAccess.
474 getConstructorSignature(constructorToCall),
475 langReflectAccess.
476 getConstructorAnnotations(constructorToCall),
477 langReflectAccess.
478 getConstructorParameterAnnotations(constructorToCall));
479 setConstructorAccessor(c, acc);
480 c.setAccessible(true);
481 return c;
482 }
483
484 public final MethodHandle readObjectForSerialization(Class<?> cl) {
485 return findReadWriteObjectForSerialization(cl, "readObject", ObjectInputStream.class);
486 }
487
488 public final MethodHandle readObjectNoDataForSerialization(Class<?> cl) {
489 return findReadWriteObjectForSerialization(cl, "readObjectNoData", ObjectInputStream.class);
490 }
491
492 public final MethodHandle writeObjectForSerialization(Class<?> cl) {
493 return findReadWriteObjectForSerialization(cl, "writeObject", ObjectOutputStream.class);
494 }
495
496 private final MethodHandle findReadWriteObjectForSerialization(Class<?> cl,
497 String methodName,
498 Class<?> streamClass) {
499 if (!Serializable.class.isAssignableFrom(cl)) {
500 return null;
501 }
502
503 try {
504 Method meth = cl.getDeclaredMethod(methodName, streamClass);
505 int mods = meth.getModifiers();
506 if (meth.getReturnType() != Void.TYPE ||
507 Modifier.isStatic(mods) ||
508 !Modifier.isPrivate(mods)) {
509 return null;
510 }
511 meth.setAccessible(true);
512 return MethodHandles.lookup().unreflect(meth);
513 } catch (NoSuchMethodException ex) {
514 return null;
515 } catch (IllegalAccessException ex1) {
516 throw new InternalError("Error", ex1);
517 }
518 }
519
520 /**
521 * Returns a MethodHandle for {@code writeReplace} on the serializable class
522 * or null if no match found.
523 * @param cl a serializable class
524 * @returnss the {@code writeReplace} MethodHandle or {@code null} if not found
525 */
526 public final MethodHandle writeReplaceForSerialization(Class<?> cl) {
527 return getReplaceResolveForSerialization(cl, "writeReplace");
528 }
529
530 /**
531 * Returns a MethodHandle for {@code readResolve} on the serializable class
532 * or null if no match found.
533 * @param cl a serializable class
534 * @returns the {@code writeReplace} MethodHandle or {@code null} if not found
535 */
536 public final MethodHandle readResolveForSerialization(Class<?> cl) {
537 return getReplaceResolveForSerialization(cl, "readResolve");
538 }
539
540 /**
541 * Lookup readResolve or writeReplace on a class with specified
542 * signature constraints.
543 * @param cl a serializable class
544 * @param methodName the method name to find
545 * @returns a MethodHandle for the method or {@code null} if not found or
546 * has the wrong signature.
547 */
548 private MethodHandle getReplaceResolveForSerialization(Class<?> cl,
549 String methodName) {
550 if (!Serializable.class.isAssignableFrom(cl)) {
551 return null;
552 }
553
554 Class<?> defCl = cl;
555 while (defCl != null) {
556 try {
557 Method m = defCl.getDeclaredMethod(methodName);
558 if (m.getReturnType() != Object.class) {
559 return null;
560 }
561 int mods = m.getModifiers();
562 if (Modifier.isStatic(mods) | Modifier.isAbstract(mods)) {
563 return null;
564 } else if (Modifier.isPublic(mods) | Modifier.isProtected(mods)) {
565 // fall through
566 } else if (Modifier.isPrivate(mods) && (cl != defCl)) {
567 return null;
568 } else if (!packageEquals(cl, defCl)) {
569 return null;
570 }
571 try {
572 // Normal return
573 m.setAccessible(true);
574 return MethodHandles.lookup().unreflect(m);
575 } catch (IllegalAccessException ex0) {
576 // setAccessible should prevent IAE
577 throw new InternalError("Error", ex0);
578 }
579 } catch (NoSuchMethodException ex) {
580 defCl = defCl.getSuperclass();
581 }
582 }
583 return null;
584 }
585
586 /**
587 * Returns true if the given class defines a static initializer method,
588 * false otherwise.
589 */
590 public final boolean hasStaticInitializerForSerialization(Class<?> cl) {
591 Method m = hasStaticInitializerMethod;
592 if (m == null) {
593 try {
594 m = ObjectStreamClass.class.getDeclaredMethod("hasStaticInitializer",
595 new Class<?>[]{Class.class});
596 m.setAccessible(true);
597 hasStaticInitializerMethod = m;
598 } catch (NoSuchMethodException ex) {
599 throw new InternalError("No such method hasStaticInitializer on "
600 + ObjectStreamClass.class, ex);
601 }
602 }
603 try {
604 return (Boolean) m.invoke(null, cl);
605 } catch (InvocationTargetException | IllegalAccessException ex) {
606 throw new InternalError("Exception invoking hasStaticInitializer", ex);
607 }
608 }
609
610 /**
611 * Return the accessible constructor for OptionalDataException signaling eof.
612 * @returns the eof constructor for OptionalDataException
613 */
614 public final Constructor<OptionalDataException> newOptionalDataExceptionForSerialization() {
615 try {
616 Constructor<OptionalDataException> boolCtor =
617 OptionalDataException.class.getDeclaredConstructor(Boolean.TYPE);
618 boolCtor.setAccessible(true);
619 return boolCtor;
620 } catch (NoSuchMethodException ex) {
621 throw new InternalError("Constructor not found", ex);
622 }
623 }
624
625 //--------------------------------------------------------------------------
626 //
627 // Internals only below this point
628 //
629
630 static int inflationThreshold() {
631 return inflationThreshold;
632 }
633
634 /** We have to defer full initialization of this class until after
635 the static initializer is run since java.lang.reflect.Method's
636 static initializer (more properly, that for
637 java.lang.reflect.AccessibleObject) causes this class's to be
638 run, before the system properties are set up. */
639 private static void checkInitted() {
640 if (initted) return;
641
642 // Defer initialization until module system is initialized so as
643 // to avoid inflation and spinning bytecode in unnamed modules
644 // during early startup.
645 if (!VM.isModuleSystemInited()) {
646 return;
647 }
648
649 Properties props = GetPropertyAction.privilegedGetProperties();
650 String val = props.getProperty("sun.reflect.noInflation");
651 if (val != null && val.equals("true")) {
652 noInflation = true;
653 }
654
655 val = props.getProperty("sun.reflect.inflationThreshold");
656 if (val != null) {
657 try {
658 inflationThreshold = Integer.parseInt(val);
659 } catch (NumberFormatException e) {
660 throw new RuntimeException("Unable to parse property sun.reflect.inflationThreshold", e);
661 }
662 }
663
664 disableSerialConstructorChecks =
665 "true".equals(props.getProperty("jdk.disableSerialConstructorChecks"));
666
667 initted = true;
668 }
669
670 /**
671 * Returns true if classes are defined in the classloader and same package, false
672 * otherwise.
673 * @param cl1 a class
674 * @param cl2 another class
675 * @returns true if the two classes are in the same classloader and package
676 */
677 private static boolean packageEquals(Class<?> cl1, Class<?> cl2) {
678 assert !cl1.isArray() && !cl2.isArray();
679
680 if (cl1 == cl2) {
681 return true;
682 }
683
684 return cl1.getClassLoader() == cl2.getClassLoader() &&
685 Objects.equals(cl1.getPackageName(), cl2.getPackageName());
686 }
687
688 }