1 /*
2 * Copyright (c) 2003, 2020, 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/classLoaderDataGraph.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "memory/universe.hpp"
32 #include "oops/klass.inline.hpp"
33 #include "prims/jvmtiGetLoadedClasses.hpp"
34 #include "runtime/handles.inline.hpp"
35 #include "runtime/jniHandles.inline.hpp"
36 #include "runtime/thread.hpp"
37 #include "utilities/stack.inline.hpp"
38
39 // The closure for GetLoadedClasses
40 class LoadedClassesClosure : public KlassClosure {
41 private:
42 Stack<jclass, mtInternal> _classStack;
43 JvmtiEnv* _env;
44 Thread* _cur_thread;
45 bool _dictionary_walk;
46
extract(jclass * result_list)47 int extract(jclass* result_list) {
48 // The size of the Stack will be 0 after extract, so get it here
49 int count = (int)_classStack.size();
50 int i = count;
51
52 // Pop all jclasses, fill backwards
53 while (!_classStack.is_empty()) {
54 result_list[--i] = _classStack.pop();
55 }
56
57 // Return the number of elements written
58 return count;
59 }
60
61 // Return current size of the Stack
get_count()62 int get_count() {
63 return (int)_classStack.size();
64 }
65
66 public:
LoadedClassesClosure(JvmtiEnv * env,bool dictionary_walk)67 LoadedClassesClosure(JvmtiEnv* env, bool dictionary_walk) :
68 _env(env),
69 _cur_thread(Thread::current()),
70 _dictionary_walk(dictionary_walk) {
71 }
72
do_klass(Klass * k)73 void do_klass(Klass* k) {
74 // Collect all jclasses
75 _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, k->java_mirror())));
76 if (_dictionary_walk) {
77 // Collect array classes this way when walking the dictionary (because array classes are
78 // not in the dictionary).
79 for (Klass* l = k->array_klass_or_null(); l != NULL; l = l->array_klass_or_null()) {
80 _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, l->java_mirror())));
81 }
82 }
83 }
84
get_result(JvmtiEnv * env,jint * classCountPtr,jclass ** classesPtr)85 jvmtiError get_result(JvmtiEnv *env, jint* classCountPtr, jclass** classesPtr) {
86 // Return results by extracting the collected contents into a list
87 // allocated via JvmtiEnv
88 jclass* result_list;
89 jvmtiError error = env->Allocate(get_count() * sizeof(jclass),
90 (unsigned char**)&result_list);
91
92 if (error == JVMTI_ERROR_NONE) {
93 int count = extract(result_list);
94 *classCountPtr = count;
95 *classesPtr = result_list;
96 }
97 return error;
98 }
99 };
100
101 jvmtiError
getLoadedClasses(JvmtiEnv * env,jint * classCountPtr,jclass ** classesPtr)102 JvmtiGetLoadedClasses::getLoadedClasses(JvmtiEnv *env, jint* classCountPtr, jclass** classesPtr) {
103
104 LoadedClassesClosure closure(env, false);
105 {
106 // To get a consistent list of classes we need MultiArray_lock to ensure
107 // array classes aren't created.
108 MutexLocker ma(MultiArray_lock);
109
110 // Iterate through all classes in ClassLoaderDataGraph
111 // and collect them using the LoadedClassesClosure
112 MutexLocker mcld(ClassLoaderDataGraph_lock);
113 ClassLoaderDataGraph::loaded_classes_do(&closure);
114 }
115
116 return closure.get_result(env, classCountPtr, classesPtr);
117 }
118
119 jvmtiError
getClassLoaderClasses(JvmtiEnv * env,jobject initiatingLoader,jint * classCountPtr,jclass ** classesPtr)120 JvmtiGetLoadedClasses::getClassLoaderClasses(JvmtiEnv *env, jobject initiatingLoader,
121 jint* classCountPtr, jclass** classesPtr) {
122
123 LoadedClassesClosure closure(env, true);
124 {
125 // To get a consistent list of classes we need MultiArray_lock to ensure
126 // array classes aren't created during this walk.
127 MutexLocker ma(MultiArray_lock);
128 MutexLocker sd(SystemDictionary_lock);
129 oop loader = JNIHandles::resolve(initiatingLoader);
130 // All classes loaded from this loader as initiating loader are
131 // requested, so only need to walk this loader's ClassLoaderData
132 // dictionary, or the NULL ClassLoaderData dictionary for bootstrap loader.
133 if (loader != NULL) {
134 ClassLoaderData* data = java_lang_ClassLoader::loader_data_acquire(loader);
135 // ClassLoader may not be used yet for loading.
136 if (data != NULL && data->dictionary() != NULL) {
137 data->dictionary()->all_entries_do(&closure);
138 }
139 } else {
140 ClassLoaderData::the_null_class_loader_data()->dictionary()->all_entries_do(&closure);
141 }
142 // Get basic arrays for all loaders.
143 Universe::basic_type_classes_do(&closure);
144 }
145
146 return closure.get_result(env, classCountPtr, classesPtr);
147 }
148