1 /*
2 * Copyright (c) 2003, 2010, 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 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "memory/universe.inline.hpp"
28 #include "prims/jvmtiGetLoadedClasses.hpp"
29 #include "runtime/thread.hpp"
30
31
32
33 // The closure for GetLoadedClasses and GetClassLoaderClasses
34 class JvmtiGetLoadedClassesClosure : public StackObj {
35 // Since the SystemDictionary::classes_do callback
36 // doesn't pass a closureData pointer,
37 // we use a thread-local slot to hold a pointer to
38 // a stack allocated instance of this structure.
39 private:
40 jobject _initiatingLoader;
41 int _count;
42 Handle* _list;
43 int _index;
44
45 private:
46 // Getting and setting the thread local pointer
47 static JvmtiGetLoadedClassesClosure* get_this() {
48 JvmtiGetLoadedClassesClosure* result = NULL;
49 JavaThread* thread = JavaThread::current();
50 result = thread->get_jvmti_get_loaded_classes_closure();
51 return result;
52 }
53 static void set_this(JvmtiGetLoadedClassesClosure* that) {
54 JavaThread* thread = JavaThread::current();
55 thread->set_jvmti_get_loaded_classes_closure(that);
56 }
57
58 public:
59 // Constructor/Destructor
60 JvmtiGetLoadedClassesClosure() {
61 JvmtiGetLoadedClassesClosure* that = get_this();
62 assert(that == NULL, "JvmtiGetLoadedClassesClosure in use");
63 _initiatingLoader = NULL;
64 _count = 0;
65 _list = NULL;
66 _index = 0;
67 set_this(this);
68 }
69
70 JvmtiGetLoadedClassesClosure(jobject initiatingLoader) {
71 JvmtiGetLoadedClassesClosure* that = get_this();
72 assert(that == NULL, "JvmtiGetLoadedClassesClosure in use");
73 _initiatingLoader = initiatingLoader;
74 _count = 0;
75 _list = NULL;
76 _index = 0;
77 set_this(this);
78 }
79
80 ~JvmtiGetLoadedClassesClosure() {
81 JvmtiGetLoadedClassesClosure* that = get_this();
82 assert(that != NULL, "JvmtiGetLoadedClassesClosure not found");
83 set_this(NULL);
84 _initiatingLoader = NULL;
85 _count = 0;
86 if (_list != NULL) {
87 FreeHeap(_list);
88 _list = NULL;
89 }
90 _index = 0;
91 }
92
93 // Accessors.
94 jobject get_initiatingLoader() {
95 return _initiatingLoader;
96 }
97
98 int get_count() {
99 return _count;
100 }
101
102 void set_count(int value) {
103 _count = value;
104 }
105
106 Handle* get_list() {
107 return _list;
108 }
109
110 void set_list(Handle* value) {
111 _list = value;
112 }
113
114 int get_index() {
115 return _index;
116 }
117
118 void set_index(int value) {
119 _index = value;
120 }
121
122 Handle get_element(int index) {
123 if ((_list != NULL) && (index < _count)) {
124 return _list[index];
125 } else {
126 assert(false, "empty get_element");
127 return Handle();
128 }
129 }
130
131 void set_element(int index, Handle value) {
132 if ((_list != NULL) && (index < _count)) {
133 _list[index] = value;
134 } else {
135 assert(false, "bad set_element");
136 }
137 }
138
139 // Other predicates
140 bool available() {
141 return (_list != NULL);
142 }
143
144 #ifdef ASSERT
145 // For debugging.
146 void check(int limit) {
147 for (int i = 0; i < limit; i += 1) {
148 assert(Universe::heap()->is_in(get_element(i)()), "check fails");
149 }
150 }
151 #endif
152
153 // Public methods that get called within the scope of the closure
154 void allocate() {
155 _list = NEW_C_HEAP_ARRAY(Handle, _count);
156 assert(_list != NULL, "Out of memory");
157 if (_list == NULL) {
158 _count = 0;
159 }
160 }
161
162 void extract(JvmtiEnv *env, jclass* result) {
163 for (int index = 0; index < _count; index += 1) {
164 result[index] = (jclass) env->jni_reference(get_element(index));
165 }
166 }
167
168 // Finally, the static methods that are the callbacks
169 static void increment(klassOop k) {
170 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
171 if (that->get_initiatingLoader() == NULL) {
172 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
173 that->set_count(that->get_count() + 1);
174 }
175 } else if (k != NULL) {
176 // if initiating loader not null, just include the instance with 1 dimension
177 that->set_count(that->get_count() + 1);
178 }
179 }
180
181 static void increment_with_loader(klassOop k, oop loader) {
182 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
183 if (loader == JNIHandles::resolve(that->get_initiatingLoader())) {
184 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
185 that->set_count(that->get_count() + 1);
186 }
187 }
188 }
189
190 static void prim_array_increment_with_loader(klassOop array, oop loader) {
191 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
192 if (loader == JNIHandles::resolve(that->get_initiatingLoader())) {
193 that->set_count(that->get_count() + 1);
194 }
195 }
196
197 static void add(klassOop k) {
198 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
199 if (that->available()) {
200 if (that->get_initiatingLoader() == NULL) {
201 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
202 oop mirror = Klass::cast(l)->java_mirror();
203 that->set_element(that->get_index(), mirror);
204 that->set_index(that->get_index() + 1);
205 }
206 } else if (k != NULL) {
207 // if initiating loader not null, just include the instance with 1 dimension
208 oop mirror = Klass::cast(k)->java_mirror();
209 that->set_element(that->get_index(), mirror);
210 that->set_index(that->get_index() + 1);
211 }
212 }
213 }
214
215 static void add_with_loader(klassOop k, oop loader) {
216 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
217 if (that->available()) {
218 if (loader == JNIHandles::resolve(that->get_initiatingLoader())) {
219 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
220 oop mirror = Klass::cast(l)->java_mirror();
221 that->set_element(that->get_index(), mirror);
222 that->set_index(that->get_index() + 1);
223 }
224 }
225 }
226 }
227
228 // increment the count for the given basic type array class (and any
229 // multi-dimensional arrays). For example, for [B we check for
230 // [[B, [[[B, .. and the count is incremented for each one that exists.
231 static void increment_for_basic_type_arrays(klassOop k) {
232 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
233 assert(that != NULL, "no JvmtiGetLoadedClassesClosure");
234 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
235 that->set_count(that->get_count() + 1);
236 }
237 }
238
239 // add the basic type array class and its multi-dimensional array classes to the list
240 static void add_for_basic_type_arrays(klassOop k) {
241 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
242 assert(that != NULL, "no JvmtiGetLoadedClassesClosure");
243 assert(that->available(), "no list");
244 for (klassOop l = k; l != NULL; l = Klass::cast(l)->array_klass_or_null()) {
245 oop mirror = Klass::cast(l)->java_mirror();
246 that->set_element(that->get_index(), mirror);
247 that->set_index(that->get_index() + 1);
248 }
249 }
250 };
251
252
253 jvmtiError
254 JvmtiGetLoadedClasses::getLoadedClasses(JvmtiEnv *env, jint* classCountPtr, jclass** classesPtr) {
255 // Since SystemDictionary::classes_do only takes a function pointer
256 // and doesn't call back with a closure data pointer,
257 // we can only pass static methods.
258
259 JvmtiGetLoadedClassesClosure closure;
260 {
261 // To get a consistent list of classes we need MultiArray_lock to ensure
262 // array classes aren't created, and SystemDictionary_lock to ensure that
263 // classes aren't added to the system dictionary,
264 MutexLocker ma(MultiArray_lock);
265 MutexLocker sd(SystemDictionary_lock);
266
267 // First, count the classes
268 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::increment);
269 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::increment);
270 // Next, fill in the classes
271 closure.allocate();
272 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::add);
273 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::add);
274 // Drop the SystemDictionary_lock, so the results could be wrong from here,
275 // but we still have a snapshot.
276 }
277 // Post results
278 jclass* result_list;
279 jvmtiError err = env->Allocate(closure.get_count() * sizeof(jclass),
280 (unsigned char**)&result_list);
281 if (err != JVMTI_ERROR_NONE) {
282 return err;
283 }
284 closure.extract(env, result_list);
285 *classCountPtr = closure.get_count();
286 *classesPtr = result_list;
287 return JVMTI_ERROR_NONE;
288 }
289
290 jvmtiError
291 JvmtiGetLoadedClasses::getClassLoaderClasses(JvmtiEnv *env, jobject initiatingLoader,
292 jint* classCountPtr, jclass** classesPtr) {
293 // Since SystemDictionary::classes_do only takes a function pointer
294 // and doesn't call back with a closure data pointer,
295 // we can only pass static methods.
296 JvmtiGetLoadedClassesClosure closure(initiatingLoader);
297 {
298 // To get a consistent list of classes we need MultiArray_lock to ensure
299 // array classes aren't created, and SystemDictionary_lock to ensure that
300 // classes aren't added to the system dictionary,
301 MutexLocker ma(MultiArray_lock);
302 MutexLocker sd(SystemDictionary_lock);
303 // First, count the classes in the system dictionary which have this loader recorded
304 // as an initiating loader. For basic type arrays this information is not recorded
305 // so GetClassLoaderClasses will return all of the basic type arrays. This is okay
306 // because the defining loader for basic type arrays is always the boot class loader
307 // and these classes are "visible" to all loaders.
308 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::increment_with_loader);
309 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::increment_for_basic_type_arrays);
310 // Next, fill in the classes
311 closure.allocate();
312 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::add_with_loader);
313 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::add_for_basic_type_arrays);
314 // Drop the SystemDictionary_lock, so the results could be wrong from here,
315 // but we still have a snapshot.
316 }
317 // Post results
318 jclass* result_list;
319 jvmtiError err = env->Allocate(closure.get_count() * sizeof(jclass),
320 (unsigned char**)&result_list);
321 if (err != JVMTI_ERROR_NONE) {
322 return err;
323 }
324 closure.extract(env, result_list);
325 *classCountPtr = closure.get_count();
326 *classesPtr = result_list;
327 return JVMTI_ERROR_NONE;
328 }