1 /*
2 * Copyright (c) 2003, 2013, 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 "gc_interface/collectedHeap.inline.hpp"
28 #include "memory/universe.inline.hpp"
29 #include "prims/jvmtiGetLoadedClasses.hpp"
30 #include "runtime/thread.hpp"
31 #include "utilities/stack.inline.hpp"
32
33 // The closure for GetLoadedClasses
34 class LoadedClassesClosure : public KlassClosure {
35 private:
36 Stack<jclass, mtInternal> _classStack;
37 JvmtiEnv* _env;
38
39 public:
40 LoadedClassesClosure(JvmtiEnv* env) {
41 _env = env;
42 }
43
44 void do_klass(Klass* k) {
45 // Collect all jclasses
46 _classStack.push((jclass) _env->jni_reference(k->java_mirror()));
47 }
48
49 int extract(jclass* result_list) {
50 // The size of the Stack will be 0 after extract, so get it here
51 int count = (int)_classStack.size();
52 int i = count;
53
54 // Pop all jclasses, fill backwards
55 while (!_classStack.is_empty()) {
56 result_list[--i] = _classStack.pop();
57 }
58
59 // Return the number of elements written
60 return count;
61 }
62
63 // Return current size of the Stack
64 int get_count() {
65 return (int)_classStack.size();
66 }
67 };
68
69 // The closure for GetClassLoaderClasses
70 class JvmtiGetLoadedClassesClosure : public StackObj {
71 // Since the SystemDictionary::classes_do callback
72 // doesn't pass a closureData pointer,
73 // we use a thread-local slot to hold a pointer to
74 // a stack allocated instance of this structure.
75 private:
76 jobject _initiatingLoader;
77 int _count;
78 Handle* _list;
79 int _index;
80
81 private:
82 // Getting and setting the thread local pointer
83 static JvmtiGetLoadedClassesClosure* get_this() {
84 JvmtiGetLoadedClassesClosure* result = NULL;
85 JavaThread* thread = JavaThread::current();
86 result = thread->get_jvmti_get_loaded_classes_closure();
87 return result;
88 }
89 static void set_this(JvmtiGetLoadedClassesClosure* that) {
90 JavaThread* thread = JavaThread::current();
91 thread->set_jvmti_get_loaded_classes_closure(that);
92 }
93
94 public:
95 // Constructor/Destructor
96 JvmtiGetLoadedClassesClosure() {
97 JvmtiGetLoadedClassesClosure* that = get_this();
98 assert(that == NULL, "JvmtiGetLoadedClassesClosure in use");
99 _initiatingLoader = NULL;
100 _count = 0;
101 _list = NULL;
102 _index = 0;
103 set_this(this);
104 }
105
106 JvmtiGetLoadedClassesClosure(jobject initiatingLoader) {
107 JvmtiGetLoadedClassesClosure* that = get_this();
108 assert(that == NULL, "JvmtiGetLoadedClassesClosure in use");
109 _initiatingLoader = initiatingLoader;
110 _count = 0;
111 _list = NULL;
112 _index = 0;
113 set_this(this);
114 }
115
116 ~JvmtiGetLoadedClassesClosure() {
117 JvmtiGetLoadedClassesClosure* that = get_this();
118 assert(that != NULL, "JvmtiGetLoadedClassesClosure not found");
119 set_this(NULL);
120 _initiatingLoader = NULL;
121 _count = 0;
122 if (_list != NULL) {
123 FreeHeap(_list);
124 _list = NULL;
125 }
126 _index = 0;
127 }
128
129 // Accessors.
130 jobject get_initiatingLoader() {
131 return _initiatingLoader;
132 }
133
134 int get_count() {
135 return _count;
136 }
137
138 void set_count(int value) {
139 _count = value;
140 }
141
142 Handle* get_list() {
143 return _list;
144 }
145
146 void set_list(Handle* value) {
147 _list = value;
148 }
149
150 int get_index() {
151 return _index;
152 }
153
154 void set_index(int value) {
155 _index = value;
156 }
157
158 Handle get_element(int index) {
159 if ((_list != NULL) && (index < _count)) {
160 return _list[index];
161 } else {
162 assert(false, "empty get_element");
163 return Handle();
164 }
165 }
166
167 void set_element(int index, Handle value) {
168 if ((_list != NULL) && (index < _count)) {
169 _list[index] = value;
170 } else {
171 assert(false, "bad set_element");
172 }
173 }
174
175 // Other predicates
176 bool available() {
177 return (_list != NULL);
178 }
179
180 #ifdef ASSERT
181 // For debugging.
182 void check(int limit) {
183 for (int i = 0; i < limit; i += 1) {
184 assert(Universe::heap()->is_in(get_element(i)()), "check fails");
185 }
186 }
187 #endif
188
189 // Public methods that get called within the scope of the closure
190 void allocate() {
191 _list = NEW_C_HEAP_ARRAY(Handle, _count, mtInternal);
192 assert(_list != NULL, "Out of memory");
193 if (_list == NULL) {
194 _count = 0;
195 }
196 }
197
198 void extract(JvmtiEnv *env, jclass* result) {
199 for (int index = 0; index < _count; index += 1) {
200 result[index] = (jclass) env->jni_reference(get_element(index));
201 }
202 }
203
204 static void increment_with_loader(Klass* k, ClassLoaderData* loader_data) {
205 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
206 oop class_loader = loader_data->class_loader();
207 if (class_loader == JNIHandles::resolve(that->get_initiatingLoader())) {
208 for (Klass* l = k; l != NULL; l = l->array_klass_or_null()) {
209 that->set_count(that->get_count() + 1);
210 }
211 }
212 }
213
214 static void prim_array_increment_with_loader(Klass* array, ClassLoaderData* loader_data) {
215 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
216 oop class_loader = loader_data->class_loader();
217 if (class_loader == JNIHandles::resolve(that->get_initiatingLoader())) {
218 that->set_count(that->get_count() + 1);
219 }
220 }
221
222 static void add_with_loader(Klass* k, ClassLoaderData* loader_data) {
223 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
224 if (that->available()) {
225 oop class_loader = loader_data->class_loader();
226 if (class_loader == JNIHandles::resolve(that->get_initiatingLoader())) {
227 for (Klass* l = k; l != NULL; l = l->array_klass_or_null()) {
228 oop mirror = l->java_mirror();
229 that->set_element(that->get_index(), mirror);
230 that->set_index(that->get_index() + 1);
231 }
232 }
233 }
234 }
235
236 // increment the count for the given basic type array class (and any
237 // multi-dimensional arrays). For example, for [B we check for
238 // [[B, [[[B, .. and the count is incremented for each one that exists.
239 static void increment_for_basic_type_arrays(Klass* k) {
240 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
241 assert(that != NULL, "no JvmtiGetLoadedClassesClosure");
242 for (Klass* l = k; l != NULL; l = l->array_klass_or_null()) {
243 that->set_count(that->get_count() + 1);
244 }
245 }
246
247 // add the basic type array class and its multi-dimensional array classes to the list
248 static void add_for_basic_type_arrays(Klass* k) {
249 JvmtiGetLoadedClassesClosure* that = JvmtiGetLoadedClassesClosure::get_this();
250 assert(that != NULL, "no JvmtiGetLoadedClassesClosure");
251 assert(that->available(), "no list");
252 for (Klass* l = k; l != NULL; l = l->array_klass_or_null()) {
253 oop mirror = l->java_mirror();
254 that->set_element(that->get_index(), mirror);
255 that->set_index(that->get_index() + 1);
256 }
257 }
258 };
259
260
261 jvmtiError
262 JvmtiGetLoadedClasses::getLoadedClasses(JvmtiEnv *env, jint* classCountPtr, jclass** classesPtr) {
263
264 LoadedClassesClosure closure(env);
265 {
266 // To get a consistent list of classes we need MultiArray_lock to ensure
267 // array classes aren't created.
268 MutexLocker ma(MultiArray_lock);
269
270 // Iterate through all classes in ClassLoaderDataGraph
271 // and collect them using the LoadedClassesClosure
272 ClassLoaderDataGraph::loaded_classes_do(&closure);
273 }
274
275 // Return results by extracting the collected contents into a list
276 // allocated via JvmtiEnv
277 jclass* result_list;
278 jvmtiError error = env->Allocate(closure.get_count() * sizeof(jclass),
279 (unsigned char**)&result_list);
280
281 if (error == JVMTI_ERROR_NONE) {
282 int count = closure.extract(result_list);
283 *classCountPtr = count;
284 *classesPtr = result_list;
285 }
286 return error;
287 }
288
289 jvmtiError
290 JvmtiGetLoadedClasses::getClassLoaderClasses(JvmtiEnv *env, jobject initiatingLoader,
291 jint* classCountPtr, jclass** classesPtr) {
292 // Since SystemDictionary::classes_do only takes a function pointer
293 // and doesn't call back with a closure data pointer,
294 // we can only pass static methods.
295 JvmtiGetLoadedClassesClosure closure(initiatingLoader);
296 {
297 // To get a consistent list of classes we need MultiArray_lock to ensure
298 // array classes aren't created, and SystemDictionary_lock to ensure that
299 // classes aren't added to the system dictionary,
300 MutexLocker ma(MultiArray_lock);
301 MutexLocker sd(SystemDictionary_lock);
302 // First, count the classes in the system dictionary which have this loader recorded
303 // as an initiating loader. For basic type arrays this information is not recorded
304 // so GetClassLoaderClasses will return all of the basic type arrays. This is okay
305 // because the defining loader for basic type arrays is always the boot class loader
306 // and these classes are "visible" to all loaders.
307 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::increment_with_loader);
308 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::increment_for_basic_type_arrays);
309 // Next, fill in the classes
310 closure.allocate();
311 SystemDictionary::classes_do(&JvmtiGetLoadedClassesClosure::add_with_loader);
312 Universe::basic_type_classes_do(&JvmtiGetLoadedClassesClosure::add_for_basic_type_arrays);
313 // Drop the SystemDictionary_lock, so the results could be wrong from here,
314 // but we still have a snapshot.
315 }
316 // Post results
317 jclass* result_list;
318 jvmtiError err = env->Allocate(closure.get_count() * sizeof(jclass),
319 (unsigned char**)&result_list);
320 if (err != JVMTI_ERROR_NONE) {
321 return err;
322 }
323 closure.extract(env, result_list);
324 *classCountPtr = closure.get_count();
325 *classesPtr = result_list;
326 return JVMTI_ERROR_NONE;
327 }