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