1 /* Copyright (C) 2017 The Android Open Source Project
2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3  *
4  * This file implements interfaces from the file jvmti.h. This implementation
5  * is licensed under the same terms as the file jvmti.h.  The
6  * copyright and license information for the file jvmti.h follows.
7  *
8  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
10  *
11  * This code is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License version 2 only, as
13  * published by the Free Software Foundation.  Oracle designates this
14  * particular file as subject to the "Classpath" exception as provided
15  * by Oracle in the LICENSE file that accompanied this code.
16  *
17  * This code is distributed in the hope that it will be useful, but WITHOUT
18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
20  * version 2 for more details (a copy is included in the LICENSE file that
21  * accompanied this code).
22  *
23  * You should have received a copy of the GNU General Public License version
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31 
32 #include "ti_threadgroup.h"
33 
34 #include "art_field-inl.h"
35 #include "art_jvmti.h"
36 #include "base/logging.h"
37 #include "base/macros.h"
38 #include "base/mutex.h"
39 #include "handle_scope-inl.h"
40 #include "jni/jni_internal.h"
41 #include "mirror/class.h"
42 #include "mirror/object-inl.h"
43 #include "mirror/string.h"
44 #include "obj_ptr.h"
45 #include "object_lock.h"
46 #include "runtime.h"
47 #include "scoped_thread_state_change-inl.h"
48 #include "thread-current-inl.h"
49 #include "thread_list.h"
50 #include "well_known_classes.h"
51 
52 namespace openjdkjvmti {
53 
54 
GetTopThreadGroups(jvmtiEnv * env,jint * group_count_ptr,jthreadGroup ** groups_ptr)55 jvmtiError ThreadGroupUtil::GetTopThreadGroups(jvmtiEnv* env,
56                                                jint* group_count_ptr,
57                                                jthreadGroup** groups_ptr) {
58   // We only have a single top group. So we can take the current thread and move upwards.
59   if (group_count_ptr == nullptr || groups_ptr == nullptr) {
60     return ERR(NULL_POINTER);
61   }
62 
63   art::Runtime* runtime = art::Runtime::Current();
64   if (runtime == nullptr) {
65     // Must be starting the runtime, or dying.
66     return ERR(WRONG_PHASE);
67   }
68 
69   jobject sys_thread_group = runtime->GetSystemThreadGroup();
70   if (sys_thread_group == nullptr) {
71     // Seems we're still starting up.
72     return ERR(WRONG_PHASE);
73   }
74 
75   unsigned char* data;
76   jvmtiError result = env->Allocate(sizeof(jthreadGroup), &data);
77   if (result != ERR(NONE)) {
78     return result;
79   }
80 
81   jthreadGroup* groups = reinterpret_cast<jthreadGroup*>(data);
82   *groups =
83       reinterpret_cast<JNIEnv*>(art::Thread::Current()->GetJniEnv())->NewLocalRef(sys_thread_group);
84   *groups_ptr = groups;
85   *group_count_ptr = 1;
86 
87   return ERR(NONE);
88 }
89 
GetThreadGroupInfo(jvmtiEnv * env,jthreadGroup group,jvmtiThreadGroupInfo * info_ptr)90 jvmtiError ThreadGroupUtil::GetThreadGroupInfo(jvmtiEnv* env,
91                                                jthreadGroup group,
92                                                jvmtiThreadGroupInfo* info_ptr) {
93   if (group == nullptr) {
94     return ERR(INVALID_THREAD_GROUP);
95   }
96 
97   art::ScopedObjectAccess soa(art::Thread::Current());
98   if (soa.Env()->IsInstanceOf(group, art::WellKnownClasses::java_lang_ThreadGroup) == JNI_FALSE) {
99     return ERR(INVALID_THREAD_GROUP);
100   }
101 
102   art::StackHandleScope<2> hs(soa.Self());
103   art::Handle<art::mirror::Class> tg_class(
104       hs.NewHandle(soa.Decode<art::mirror::Class>(art::WellKnownClasses::java_lang_ThreadGroup)));
105   art::Handle<art::mirror::Object> obj(hs.NewHandle(soa.Decode<art::mirror::Object>(group)));
106 
107   // Do the name first. It's the only thing that can fail.
108   {
109     art::ArtField* name_field =
110         art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_name);
111     CHECK(name_field != nullptr);
112     art::ObjPtr<art::mirror::String> name_obj =
113         art::ObjPtr<art::mirror::String>::DownCast(name_field->GetObject(obj.Get()));
114     std::string tmp_str;
115     const char* tmp_cstr;
116     if (name_obj == nullptr) {
117       tmp_cstr = "";
118     } else {
119       tmp_str = name_obj->ToModifiedUtf8();
120       tmp_cstr = tmp_str.c_str();
121     }
122     jvmtiError result;
123     JvmtiUniquePtr<char[]> copy = CopyString(env, tmp_cstr, &result);
124     if (copy == nullptr) {
125       return result;
126     }
127     info_ptr->name = copy.release();
128   }
129 
130   // Parent.
131   {
132     art::ArtField* parent_field =
133         art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_parent);
134     CHECK(parent_field != nullptr);
135     art::ObjPtr<art::mirror::Object> parent_group = parent_field->GetObject(obj.Get());
136     info_ptr->parent = parent_group == nullptr
137                            ? nullptr
138                            : soa.AddLocalReference<jthreadGroup>(parent_group);
139   }
140 
141   // Max priority.
142   {
143     art::ArtField* prio_field = tg_class->FindDeclaredInstanceField("maxPriority", "I");
144     CHECK(prio_field != nullptr);
145     info_ptr->max_priority = static_cast<jint>(prio_field->GetInt(obj.Get()));
146   }
147 
148   // Daemon.
149   {
150     art::ArtField* daemon_field = tg_class->FindDeclaredInstanceField("daemon", "Z");
151     CHECK(daemon_field != nullptr);
152     info_ptr->is_daemon = daemon_field->GetBoolean(obj.Get()) == 0 ? JNI_FALSE : JNI_TRUE;
153   }
154 
155   return ERR(NONE);
156 }
157 
158 
IsInDesiredThreadGroup(art::Handle<art::mirror::Object> desired_thread_group,art::ObjPtr<art::mirror::Object> peer)159 static bool IsInDesiredThreadGroup(art::Handle<art::mirror::Object> desired_thread_group,
160                                    art::ObjPtr<art::mirror::Object> peer)
161     REQUIRES_SHARED(art::Locks::mutator_lock_) {
162   CHECK(desired_thread_group != nullptr);
163 
164   art::ArtField* thread_group_field =
165       art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_group);
166   DCHECK(thread_group_field != nullptr);
167   art::ObjPtr<art::mirror::Object> group = thread_group_field->GetObject(peer);
168   return (group == desired_thread_group.Get());
169 }
170 
GetThreads(art::Handle<art::mirror::Object> thread_group,std::vector<art::ObjPtr<art::mirror::Object>> * thread_peers)171 static void GetThreads(art::Handle<art::mirror::Object> thread_group,
172                        std::vector<art::ObjPtr<art::mirror::Object>>* thread_peers)
173     REQUIRES_SHARED(art::Locks::mutator_lock_) REQUIRES(!art::Locks::thread_list_lock_) {
174   CHECK(thread_group != nullptr);
175 
176   art::MutexLock mu(art::Thread::Current(), *art::Locks::thread_list_lock_);
177   for (art::Thread* t : art::Runtime::Current()->GetThreadList()->GetList()) {
178     if (t->IsStillStarting()) {
179       continue;
180     }
181     art::ObjPtr<art::mirror::Object> peer = t->GetPeerFromOtherThread();
182     if (peer == nullptr) {
183       continue;
184     }
185     if (IsInDesiredThreadGroup(thread_group, peer)) {
186       thread_peers->push_back(peer);
187     }
188   }
189 }
190 
GetChildThreadGroups(art::Handle<art::mirror::Object> thread_group,std::vector<art::ObjPtr<art::mirror::Object>> * thread_groups)191 static void GetChildThreadGroups(art::Handle<art::mirror::Object> thread_group,
192                                  std::vector<art::ObjPtr<art::mirror::Object>>* thread_groups)
193     REQUIRES_SHARED(art::Locks::mutator_lock_) {
194   CHECK(thread_group != nullptr);
195 
196   // Get the ThreadGroup[] "groups" out of this thread group...
197   art::ArtField* groups_field =
198       art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_groups);
199   art::ObjPtr<art::mirror::Object> groups_array = groups_field->GetObject(thread_group.Get());
200 
201   if (groups_array == nullptr) {
202     return;
203   }
204   CHECK(groups_array->IsObjectArray());
205 
206   art::ObjPtr<art::mirror::ObjectArray<art::mirror::Object>> groups_array_as_array =
207       groups_array->AsObjectArray<art::mirror::Object>();
208 
209   // Copy all non-null elements.
210   for (auto entry : groups_array_as_array->Iterate()) {
211     if (entry != nullptr) {
212       thread_groups->push_back(entry);
213     }
214   }
215 }
216 
GetThreadGroupChildren(jvmtiEnv * env,jthreadGroup group,jint * thread_count_ptr,jthread ** threads_ptr,jint * group_count_ptr,jthreadGroup ** groups_ptr)217 jvmtiError ThreadGroupUtil::GetThreadGroupChildren(jvmtiEnv* env,
218                                                    jthreadGroup group,
219                                                    jint* thread_count_ptr,
220                                                    jthread** threads_ptr,
221                                                    jint* group_count_ptr,
222                                                    jthreadGroup** groups_ptr) {
223   if (group == nullptr) {
224     return ERR(INVALID_THREAD_GROUP);
225   }
226 
227   art::ScopedObjectAccess soa(art::Thread::Current());
228 
229   if (!soa.Env()->IsInstanceOf(group, art::WellKnownClasses::java_lang_ThreadGroup)) {
230     return ERR(INVALID_THREAD_GROUP);
231   }
232 
233   art::StackHandleScope<1> hs(soa.Self());
234   art::Handle<art::mirror::Object> thread_group = hs.NewHandle(
235       soa.Decode<art::mirror::Object>(group));
236 
237   art::ObjectLock<art::mirror::Object> thread_group_lock(soa.Self(), thread_group);
238 
239   std::vector<art::ObjPtr<art::mirror::Object>> thread_peers;
240   GetThreads(thread_group, &thread_peers);
241 
242   std::vector<art::ObjPtr<art::mirror::Object>> thread_groups;
243   GetChildThreadGroups(thread_group, &thread_groups);
244 
245   JvmtiUniquePtr<jthread[]> peers_uptr;
246   if (!thread_peers.empty()) {
247     jvmtiError res;
248     peers_uptr = AllocJvmtiUniquePtr<jthread[]>(env, thread_peers.size(), &res);
249     if (peers_uptr == nullptr) {
250       return res;
251     }
252   }
253 
254   JvmtiUniquePtr<jthreadGroup[]> group_uptr;
255   if (!thread_groups.empty()) {
256     jvmtiError res;
257     group_uptr = AllocJvmtiUniquePtr<jthreadGroup[]>(env, thread_groups.size(), &res);
258     if (group_uptr == nullptr) {
259       return res;
260     }
261   }
262 
263   // Can't fail anymore from here on.
264 
265   // Copy data into out buffers.
266   for (size_t i = 0; i != thread_peers.size(); ++i) {
267     peers_uptr[i] = soa.AddLocalReference<jthread>(thread_peers[i]);
268   }
269   for (size_t i = 0; i != thread_groups.size(); ++i) {
270     group_uptr[i] = soa.AddLocalReference<jthreadGroup>(thread_groups[i]);
271   }
272 
273   *thread_count_ptr = static_cast<jint>(thread_peers.size());
274   *threads_ptr = peers_uptr.release();
275   *group_count_ptr = static_cast<jint>(thread_groups.size());
276   *groups_ptr = group_uptr.release();
277 
278   return ERR(NONE);
279 }
280 
281 }  // namespace openjdkjvmti
282