1 /*
2 * Copyright (c) 2020, 2023, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @bug 8230501
27 * @library /test/lib
28 * @enablePreview
29 * @run testng/othervm ClassDataTest
30 */
31
32 import java.io.IOException;
33 import java.io.OutputStream;
34 import java.io.UncheckedIOException;
35 import java.lang.classfile.ClassBuilder;
36 import java.lang.classfile.ClassFile;
37 import java.lang.classfile.TypeKind;
38 import java.lang.constant.ClassDesc;
39 import java.lang.constant.ConstantDescs;
40 import java.lang.constant.DirectMethodHandleDesc;
41 import java.lang.constant.DynamicConstantDesc;
42 import java.lang.constant.MethodTypeDesc;
43 import java.lang.invoke.MethodHandle;
44 import java.lang.invoke.MethodHandles;
45 import java.lang.invoke.MethodHandles.Lookup;
46 import java.lang.invoke.MethodType;
47 import java.lang.reflect.AccessFlag;
48 import java.lang.reflect.Method;
49 import java.nio.file.Files;
50 import java.nio.file.Path;
51 import java.nio.file.Paths;
52 import java.util.ArrayList;
53 import java.util.List;
54 import java.util.Map;
55 import java.util.function.Consumer;
56 import java.util.stream.Stream;
57
58 import org.testng.annotations.DataProvider;
59 import org.testng.annotations.Test;
60
61 import static java.lang.classfile.ClassFile.*;
62 import static java.lang.constant.ConstantDescs.*;
63 import static java.lang.invoke.MethodHandles.Lookup.*;
64 import static org.testng.Assert.*;
65
66 public class ClassDataTest {
67 private static final Lookup LOOKUP = MethodHandles.lookup();
68 private static final ClassDesc CD_ClassDataTest = ClassDataTest.class.describeConstable().orElseThrow();
69
70 @Test
71 public void testOriginalAccess() throws IllegalAccessException {
72 Lookup lookup = hiddenClass(20);
73 assertTrue(lookup.hasFullPrivilegeAccess());
74
75 int value = MethodHandles.classData(lookup, "_", int.class);
76 assertEquals(value, 20);
77
78 Integer i = MethodHandles.classData(lookup, "_", Integer.class);
79 assertEquals(i.intValue(), 20);
80 }
81
82 /*
83 * A lookup class with no class data.
84 */
85 @Test
86 public void noClassData() throws IllegalAccessException {
87 assertNull(MethodHandles.classData(LOOKUP, "_", Object.class));
88 }
89
90 @DataProvider(name = "teleportedLookup")
91 private Object[][] teleportedLookup() throws ReflectiveOperationException {
92 Lookup lookup = hiddenClass(30);
93 Class<?> hc = lookup.lookupClass();
94 assertClassData(lookup, 30);
95
96 int fullAccess = PUBLIC|PROTECTED|PACKAGE|MODULE|PRIVATE;
97 return new Object[][] {
98 new Object[] { MethodHandles.privateLookupIn(hc, LOOKUP), fullAccess},
99 new Object[] { LOOKUP.in(hc), fullAccess & ~(PROTECTED|PRIVATE) },
100 new Object[] { lookup.dropLookupMode(PRIVATE), fullAccess & ~(PROTECTED|PRIVATE) },
101 };
102 }
103
104 @Test(dataProvider = "teleportedLookup", expectedExceptions = { IllegalAccessException.class })
105 public void illegalAccess(Lookup lookup, int access) throws IllegalAccessException {
106 int lookupModes = lookup.lookupModes();
107 assertTrue((lookupModes & ORIGINAL) == 0);
108 assertEquals(lookupModes, access);
109 MethodHandles.classData(lookup, "_", int.class);
110 }
111
112 @Test(expectedExceptions = { ClassCastException.class })
113 public void incorrectType() throws IllegalAccessException {
114 Lookup lookup = hiddenClass(20);
115 MethodHandles.classData(lookup, "_", Long.class);
116 }
117
118 @Test(expectedExceptions = { IndexOutOfBoundsException.class })
119 public void invalidIndex() throws IllegalAccessException {
120 Lookup lookup = hiddenClass(List.of());
121 MethodHandles.classDataAt(lookup, "_", Object.class, 0);
122 }
123
124 @Test(expectedExceptions = { NullPointerException.class })
125 public void unboxNull() throws IllegalAccessException {
126 List<Integer> list = new ArrayList<>();
127 list.add(null);
128 Lookup lookup = hiddenClass(list);
129 MethodHandles.classDataAt(lookup, "_", int.class, 0);
130 }
131
132 @Test
133 public void nullElement() throws IllegalAccessException {
134 List<Object> list = new ArrayList<>();
135 list.add(null);
136 Lookup lookup = hiddenClass(list);
137 assertTrue(MethodHandles.classDataAt(lookup, "_", Object.class, 0) == null);
138 }
139
140 @Test
141 public void intClassData() throws ReflectiveOperationException {
142 ClassByteBuilder builder = new ClassByteBuilder("T1-int");
143 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, int.class).build();
144 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, 100, true);
145 int value = MethodHandles.classData(lookup, "_", int.class);
146 assertEquals(value, 100);
147 // call through condy
148 assertClassData(lookup, 100);
149 }
150
151 @Test
152 public void floatClassData() throws ReflectiveOperationException {
153 ClassByteBuilder builder = new ClassByteBuilder("T1-float");
154 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, float.class).build();
155 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, 0.1234f, true);
156 float value = MethodHandles.classData(lookup, "_", float.class);
157 assertEquals(value, 0.1234f);
158 // call through condy
159 assertClassData(lookup, 0.1234f);
160 }
161
162 @Test
163 public void classClassData() throws ReflectiveOperationException {
164 Class<?> hc = hiddenClass(100).lookupClass();
165 ClassByteBuilder builder = new ClassByteBuilder("T2");
166 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, Class.class).build();
167 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, hc, true);
168 Class<?> value = MethodHandles.classData(lookup, "_", Class.class);
169 assertEquals(value, hc);
170 // call through condy
171 assertClassData(lookup, hc);
172 }
173
174 @Test
175 public void arrayClassData() throws ReflectiveOperationException {
176 ClassByteBuilder builder = new ClassByteBuilder("T3");
177 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, String[].class).build();
178 String[] colors = new String[] { "red", "yellow", "blue"};
179 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, colors, true);
180 assertClassData(lookup, colors.clone());
181 // class data is modifiable and not a constant
182 colors[0] = "black";
183 // it will get back the modified class data
184 String[] value = MethodHandles.classData(lookup, "_", String[].class);
185 assertEquals(value, colors);
186 // even call through condy as it's not a constant
187 assertClassData(lookup, colors);
188 }
189
190 @Test
191 public void listClassData() throws ReflectiveOperationException {
192 ClassByteBuilder builder = new ClassByteBuilder("T4");
193 byte[] bytes = builder.classDataAt(ACC_PUBLIC|ACC_STATIC, Integer.class, 2).build();
194 List<Integer> cd = List.of(100, 101, 102, 103);
195 int expected = 102; // element at index=2
196 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, cd, true);
197 int value = MethodHandles.classDataAt(lookup, "_", int.class, 2);
198 assertEquals(value, expected);
199 // call through condy
200 assertClassData(lookup, expected);
201 }
202
203 @Test
204 public void arrayListClassData() throws ReflectiveOperationException {
205 ClassByteBuilder builder = new ClassByteBuilder("T4");
206 byte[] bytes = builder.classDataAt(ACC_PUBLIC|ACC_STATIC, Integer.class, 1).build();
207 ArrayList<Integer> cd = new ArrayList<>();
208 Stream.of(100, 101, 102, 103).forEach(cd::add);
209 int expected = 101; // element at index=1
210 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, cd, true);
211 int value = MethodHandles.classDataAt(lookup, "_", int.class, 1);
212 assertEquals(value, expected);
213 // call through condy
214 assertClassData(lookup, expected);
215 }
216
217 private static Lookup hiddenClass(int value) {
218 ClassByteBuilder builder = new ClassByteBuilder("HC");
219 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, int.class).build();
220 try {
221 return LOOKUP.defineHiddenClassWithClassData(bytes, value, true);
222 } catch (Throwable e) {
223 throw new RuntimeException(e);
224 }
225 }
226 private static Lookup hiddenClass(List<?> list) {
227 ClassByteBuilder builder = new ClassByteBuilder("HC");
228 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, List.class).build();
229 try {
230 return LOOKUP.defineHiddenClassWithClassData(bytes, list, true);
231 } catch (Throwable e) {
232 throw new RuntimeException(e);
233 }
234 }
235
236 @Test
237 public void condyInvokedFromVirtualMethod() throws ReflectiveOperationException {
238 ClassByteBuilder builder = new ClassByteBuilder("T5");
239 // generate classData instance method
240 byte[] bytes = builder.classData(ACC_PUBLIC, Class.class).build();
241 Lookup hcLookup = hiddenClass(100);
242 assertClassData(hcLookup, 100);
243 Class<?> hc = hcLookup.lookupClass();
244 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, hc, true);
245 Class<?> value = MethodHandles.classData(lookup, "_", Class.class);
246 assertEquals(value, hc);
247 // call through condy
248 Class<?> c = lookup.lookupClass();
249 assertClassData(lookup, c.newInstance(), hc);
250 }
251
252 @Test
253 public void immutableListClassData() throws ReflectiveOperationException {
254 ClassByteBuilder builder = new ClassByteBuilder("T6");
255 // generate classDataAt instance method
256 byte[] bytes = builder.classDataAt(ACC_PUBLIC, Integer.class, 2).build();
257 List<Integer> cd = List.of(100, 101, 102, 103);
258 int expected = 102; // element at index=2
259 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, cd, true);
260 int value = MethodHandles.classDataAt(lookup, "_", int.class, 2);
261 assertEquals(value, expected);
262 // call through condy
263 Class<?> c = lookup.lookupClass();
264 assertClassData(lookup, c.newInstance() ,expected);
265 }
266
267 /*
268 * The return value of MethodHandles::classDataAt is the element
269 * contained in the list when the method is called.
270 * If MethodHandles::classDataAt is called via condy, the value
271 * will be captured as a constant. If the class data is modified
272 * after the element at the given index is computed via condy,
273 * subsequent LDC of such ConstantDynamic entry will return the same
274 * value. However, direct invocation of MethodHandles::classDataAt
275 * will return the modified value.
276 */
277 @Test
278 public void mutableListClassData() throws ReflectiveOperationException {
279 ClassByteBuilder builder = new ClassByteBuilder("T7");
280 // generate classDataAt instance method
281 byte[] bytes = builder.classDataAt(ACC_PUBLIC, MethodType.class, 0).build();
282 MethodType mtype = MethodType.methodType(int.class, String.class);
283 List<MethodType> cd = new ArrayList<>(List.of(mtype));
284 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, cd, true);
285 // call through condy
286 Class<?> c = lookup.lookupClass();
287 assertClassData(lookup, c.newInstance(), mtype);
288 // modify the class data
289 assertTrue(cd.remove(0) == mtype);
290 cd.add(0, MethodType.methodType(void.class));
291 MethodType newMType = cd.get(0);
292 // loading the element using condy returns the original value
293 assertClassData(lookup, c.newInstance(), mtype);
294 // direct invocation of MethodHandles.classDataAt returns the modified value
295 assertEquals(MethodHandles.classDataAt(lookup, "_", MethodType.class, 0), newMType);
296 }
297
298 // helper method to extract from a class data map
299 public static <T> T getClassDataEntry(Lookup lookup, String key, Class<T> type) throws IllegalAccessException {
300 Map<String, T> cd = MethodHandles.classData(lookup, "_", Map.class);
301 return type.cast(cd.get(key));
302 }
303
304 @Test
305 public void classDataMap() throws ReflectiveOperationException {
306 ClassByteBuilder builder = new ClassByteBuilder("map");
307 // generate classData static method
308 DirectMethodHandleDesc bsm = ConstantDescs.ofConstantBootstrap(CD_ClassDataTest, "getClassDataEntry", CD_Object);
309 // generate two accessor methods to get the entries from class data
310 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, Map.class)
311 .classData(ACC_PUBLIC|ACC_STATIC, "getClass",
312 Class.class, DynamicConstantDesc.ofNamed(bsm, "class", CD_Class))
313 .classData(ACC_PUBLIC|ACC_STATIC, "getMethod",
314 MethodHandle.class, DynamicConstantDesc.ofNamed(bsm, "method", CD_MethodHandle))
315 .build();
316
317 // generate a hidden class
318 Lookup hcLookup = hiddenClass(100);
319 Class<?> hc = hcLookup.lookupClass();
320 assertClassData(hcLookup, 100);
321
322 MethodHandle mh = hcLookup.findStatic(hc, "classData", MethodType.methodType(int.class));
323 Map<String, Object> cd = Map.of("class", hc, "method", mh);
324 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, cd, true);
325 assertClassData(lookup, cd);
326
327 // validate the entries from the class data map
328 Class<?> c = lookup.lookupClass();
329 Method m = c.getMethod("getClass");
330 Class<?> v = (Class<?>)m.invoke(null);
331 assertEquals(hc, v);
332
333 Method m1 = c.getMethod("getMethod");
334 MethodHandle v1 = (MethodHandle) m1.invoke(null);
335 assertEquals(mh, v1);
336 }
337
338 @Test(expectedExceptions = { IllegalArgumentException.class })
339 public void nonDefaultName() throws ReflectiveOperationException {
340 ClassByteBuilder builder = new ClassByteBuilder("nonDefaultName");
341 byte[] bytes = builder.classData(ACC_PUBLIC|ACC_STATIC, Class.class)
342 .build();
343 Lookup lookup = LOOKUP.defineHiddenClassWithClassData(bytes, ClassDataTest.class, true);
344 assertClassData(lookup, ClassDataTest.class);
345 // throw IAE
346 MethodHandles.classData(lookup, "non_default_name", Class.class);
347 }
348
349 static class ClassByteBuilder {
350 private static final String OBJECT_CLS = "java/lang/Object";
351 private static final String MHS_CLS = "java/lang/invoke/MethodHandles";
352 private static final String CLASS_DATA_BSM_DESCR =
353 "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/Class;)Ljava/lang/Object;";
354 private Consumer<ClassBuilder> cw;
355 private final ClassDesc classname;
356
357 /**
358 * A builder to generate a class file to access class data
359 * @param classname
360 */
361 ClassByteBuilder(String classname) {
362 this.classname = ClassDesc.ofInternalName(classname);
363 this.cw = clb -> {
364 clb.withSuperclass(CD_Object);
365 clb.withFlags(AccessFlag.FINAL);
366 clb.withMethodBody(INIT_NAME, MTD_void, ACC_PUBLIC, cob -> {
367 cob.aload(0);
368 cob.invokespecial(CD_Object, INIT_NAME, MTD_void);
369 cob.return_();
370 });
371 };
372 }
373
374 byte[] build() {
375 byte[] bytes = ClassFile.of().build(classname, cw);
376 Path p = Paths.get(classname + ".class");
377 try (OutputStream os = Files.newOutputStream(p)) {
378 os.write(bytes);
379 } catch (IOException e) {
380 throw new UncheckedIOException(e);
381 }
382 return bytes;
383 }
384
385 /*
386 * Generate classData method to load class data via condy
387 */
388 ClassByteBuilder classData(int accessFlags, Class<?> returnType) {
389 ClassDesc returnDesc = returnType.describeConstable().orElseThrow();
390 MethodTypeDesc mt = MethodTypeDesc.of(returnDesc);
391 cw = cw.andThen(clb -> {
392 clb.withMethodBody("classData", mt, accessFlags, cob -> {
393 cob.loadConstant(DynamicConstantDesc.ofNamed(BSM_CLASS_DATA, DEFAULT_NAME, returnDesc));
394 cob.return_(TypeKind.from(returnType));
395 });
396 });
397 return this;
398 }
399
400 /*
401 * Generate classDataAt method to load an element from class data via condy
402 */
403 ClassByteBuilder classDataAt(int accessFlags, Class<?> returnType, int index) {
404 ClassDesc returnDesc = returnType.describeConstable().orElseThrow();
405 MethodTypeDesc mt = MethodTypeDesc.of(returnDesc);
406 cw = cw.andThen(clb -> {
407 clb.withMethodBody("classData", mt, accessFlags, cob -> {
408 cob.loadConstant(DynamicConstantDesc.ofNamed(BSM_CLASS_DATA_AT, DEFAULT_NAME, returnDesc, index));
409 cob.return_(TypeKind.from(returnType));
410 });
411 });
412 return this;
413 }
414
415 ClassByteBuilder classData(int accessFlags, String name, Class<?> returnType, DynamicConstantDesc<?> dynamic) {
416 ClassDesc returnDesc = returnType.describeConstable().orElseThrow();
417 MethodTypeDesc mt = MethodTypeDesc.of(returnDesc);
418 cw = cw.andThen(clb -> {
419 clb.withMethodBody(name, mt, accessFlags, cob -> {
420 cob.loadConstant(dynamic);
421 cob.return_(TypeKind.from(returnType));
422 });
423 });
424 return this;
425 }
426 }
427
428 /*
429 * Load an int constant from class data via condy and
430 * verify it matches the given value.
431 */
432 private void assertClassData(Lookup lookup, int value) throws ReflectiveOperationException {
433 Class<?> c = lookup.lookupClass();
434 Method m = c.getMethod("classData");
435 int v = (int) m.invoke(null);
436 assertEquals(value, v);
437 }
438
439 /*
440 * Load an int constant from class data via condy and
441 * verify it matches the given value.
442 */
443 private void assertClassData(Lookup lookup, Object o, int value) throws ReflectiveOperationException {
444 Class<?> c = lookup.lookupClass();
445 Method m = c.getMethod("classData");
446 int v = (int) m.invoke(o);
447 assertEquals(value, v);
448 }
449
450 /*
451 * Load a float constant from class data via condy and
452 * verify it matches the given value.
453 */
454 private void assertClassData(Lookup lookup, float value) throws ReflectiveOperationException {
455 Class<?> c = lookup.lookupClass();
456 Method m = c.getMethod("classData");
457 float v = (float) m.invoke(null);
458 assertEquals(value, v);
459 }
460
461 /*
462 * Load a Class constant from class data via condy and
463 * verify it matches the given value.
464 */
465 private void assertClassData(Lookup lookup, Class<?> value) throws ReflectiveOperationException {
466 Class<?> c = lookup.lookupClass();
467 Method m = c.getMethod("classData");
468 Class<?> v = (Class<?>)m.invoke(null);
469 assertEquals(value, v);
470 }
471
472 /*
473 * Load a Class from class data via condy and
474 * verify it matches the given value.
475 */
476 private void assertClassData(Lookup lookup, Object o, Class<?> value) throws ReflectiveOperationException {
477 Class<?> c = lookup.lookupClass();
478 Method m = c.getMethod("classData");
479 Object v = m.invoke(o);
480 assertEquals(value, v);
481 }
482
483 /*
484 * Load an Object from class data via condy and
485 * verify it matches the given value.
486 */
487 private void assertClassData(Lookup lookup, Object value) throws ReflectiveOperationException {
488 Class<?> c = lookup.lookupClass();
489 Method m = c.getMethod("classData");
490 Object v = m.invoke(null);
491 assertEquals(value, v);
492 }
493
494 /*
495 * Load an Object from class data via condy and
496 * verify it matches the given value.
497 */
498 private void assertClassData(Lookup lookup, Object o, Object value) throws ReflectiveOperationException {
499 Class<?> c = lookup.lookupClass();
500 Method m = c.getMethod("classData");
501 Object v = m.invoke(o);
502 assertEquals(value, v);
503 }
504 }