ti_threadgroup.cc revision a1d2f957a21319d1110bebb9a52f46fd1c67ffaf 
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
24 * 2 along with this work; if not, write to the Free Software Foundation,
25 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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27 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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30 */
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_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-inl.h"
49#include "thread_list.h"
50#include "well_known_classes.h"
51
52namespace openjdkjvmti {
53
54
55jvmtiError 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
90jvmtiError 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::ObjPtr<art::mirror::Object> obj = soa.Decode<art::mirror::Object>(group);
103
104  // Do the name first. It's the only thing that can fail.
105  {
106    art::ArtField* name_field =
107        art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_name);
108    CHECK(name_field != nullptr);
109    art::ObjPtr<art::mirror::String> name_obj =
110        art::ObjPtr<art::mirror::String>::DownCast(name_field->GetObject(obj));
111    std::string tmp_str;
112    const char* tmp_cstr;
113    if (name_obj == nullptr) {
114      tmp_cstr = "";
115    } else {
116      tmp_str = name_obj->ToModifiedUtf8();
117      tmp_cstr = tmp_str.c_str();
118    }
119    jvmtiError result;
120    JvmtiUniquePtr<char[]> copy = CopyString(env, tmp_cstr, &result);
121    if (copy == nullptr) {
122      return result;
123    }
124    info_ptr->name = copy.release();
125  }
126
127  // Parent.
128  {
129    art::ArtField* parent_field =
130        art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_parent);
131    CHECK(parent_field != nullptr);
132    art::ObjPtr<art::mirror::Object> parent_group = parent_field->GetObject(obj);
133    info_ptr->parent = parent_group == nullptr
134                           ? nullptr
135                           : soa.AddLocalReference<jthreadGroup>(parent_group);
136  }
137
138  // Max priority.
139  {
140    art::ArtField* prio_field = obj->GetClass()->FindDeclaredInstanceField("maxPriority", "I");
141    CHECK(prio_field != nullptr);
142    info_ptr->max_priority = static_cast<jint>(prio_field->GetInt(obj));
143  }
144
145  // Daemon.
146  {
147    art::ArtField* daemon_field = obj->GetClass()->FindDeclaredInstanceField("daemon", "Z");
148    CHECK(daemon_field != nullptr);
149    info_ptr->is_daemon = daemon_field->GetBoolean(obj) == 0 ? JNI_FALSE : JNI_TRUE;
150  }
151
152  return ERR(NONE);
153}
154
155
156static bool IsInDesiredThreadGroup(art::Handle<art::mirror::Object> desired_thread_group,
157                                   art::ObjPtr<art::mirror::Object> peer)
158    REQUIRES_SHARED(art::Locks::mutator_lock_) {
159  CHECK(desired_thread_group != nullptr);
160
161  art::ArtField* thread_group_field =
162      art::jni::DecodeArtField(art::WellKnownClasses::java_lang_Thread_group);
163  DCHECK(thread_group_field != nullptr);
164  art::ObjPtr<art::mirror::Object> group = thread_group_field->GetObject(peer);
165  return (group == desired_thread_group.Get());
166}
167
168static void GetThreads(art::Handle<art::mirror::Object> thread_group,
169                       std::vector<art::ObjPtr<art::mirror::Object>>* thread_peers)
170    REQUIRES_SHARED(art::Locks::mutator_lock_) REQUIRES(!art::Locks::thread_list_lock_) {
171  CHECK(thread_group != nullptr);
172
173  art::MutexLock mu(art::Thread::Current(), *art::Locks::thread_list_lock_);
174  for (art::Thread* t : art::Runtime::Current()->GetThreadList()->GetList()) {
175    if (t->IsStillStarting()) {
176      continue;
177    }
178    art::ObjPtr<art::mirror::Object> peer = t->GetPeerFromOtherThread();
179    if (peer == nullptr) {
180      continue;
181    }
182    if (IsInDesiredThreadGroup(thread_group, peer)) {
183      thread_peers->push_back(peer);
184    }
185  }
186}
187
188static void GetChildThreadGroups(art::Handle<art::mirror::Object> thread_group,
189                                 std::vector<art::ObjPtr<art::mirror::Object>>* thread_groups)
190    REQUIRES_SHARED(art::Locks::mutator_lock_) {
191  CHECK(thread_group != nullptr);
192
193  // Get the ThreadGroup[] "groups" out of this thread group...
194  art::ArtField* groups_field =
195      art::jni::DecodeArtField(art::WellKnownClasses::java_lang_ThreadGroup_groups);
196  art::ObjPtr<art::mirror::Object> groups_array = groups_field->GetObject(thread_group.Get());
197
198  if (groups_array == nullptr) {
199    return;
200  }
201  CHECK(groups_array->IsObjectArray());
202
203  art::ObjPtr<art::mirror::ObjectArray<art::mirror::Object>> groups_array_as_array =
204      groups_array->AsObjectArray<art::mirror::Object>();
205
206  // Copy all non-null elements.
207  for (int32_t i = 0; i < groups_array_as_array->GetLength(); ++i) {
208    art::ObjPtr<art::mirror::Object> entry = groups_array_as_array->Get(i);
209    if (entry != nullptr) {
210      thread_groups->push_back(entry);
211    }
212  }
213}
214
215jvmtiError ThreadGroupUtil::GetThreadGroupChildren(jvmtiEnv* env,
216                                                   jthreadGroup group,
217                                                   jint* thread_count_ptr,
218                                                   jthread** threads_ptr,
219                                                   jint* group_count_ptr,
220                                                   jthreadGroup** groups_ptr) {
221  if (group == nullptr) {
222    return ERR(INVALID_THREAD_GROUP);
223  }
224
225  art::ScopedObjectAccess soa(art::Thread::Current());
226
227  if (!soa.Env()->IsInstanceOf(group, art::WellKnownClasses::java_lang_ThreadGroup)) {
228    return ERR(INVALID_THREAD_GROUP);
229  }
230
231  art::StackHandleScope<1> hs(soa.Self());
232  art::Handle<art::mirror::Object> thread_group = hs.NewHandle(
233      soa.Decode<art::mirror::Object>(group));
234
235  art::ObjectLock<art::mirror::Object> thread_group_lock(soa.Self(), thread_group);
236
237  std::vector<art::ObjPtr<art::mirror::Object>> thread_peers;
238  GetThreads(thread_group, &thread_peers);
239
240  std::vector<art::ObjPtr<art::mirror::Object>> thread_groups;
241  GetChildThreadGroups(thread_group, &thread_groups);
242
243  JvmtiUniquePtr<jthread[]> peers_uptr;
244  if (!thread_peers.empty()) {
245    jvmtiError res;
246    peers_uptr = AllocJvmtiUniquePtr<jthread[]>(env, thread_peers.size(), &res);
247    if (peers_uptr == nullptr) {
248      return res;
249    }
250  }
251
252  JvmtiUniquePtr<jthreadGroup[]> group_uptr;
253  if (!thread_groups.empty()) {
254    jvmtiError res;
255    group_uptr = AllocJvmtiUniquePtr<jthreadGroup[]>(env, thread_groups.size(), &res);
256    if (group_uptr == nullptr) {
257      return res;
258    }
259  }
260
261  // Can't fail anymore from here on.
262
263  // Copy data into out buffers.
264  for (size_t i = 0; i != thread_peers.size(); ++i) {
265    peers_uptr[i] = soa.AddLocalReference<jthread>(thread_peers[i]);
266  }
267  for (size_t i = 0; i != thread_groups.size(); ++i) {
268    group_uptr[i] = soa.AddLocalReference<jthreadGroup>(thread_groups[i]);
269  }
270
271  *thread_count_ptr = static_cast<jint>(thread_peers.size());
272  *threads_ptr = peers_uptr.release();
273  *group_count_ptr = static_cast<jint>(thread_groups.size());
274  *groups_ptr = group_uptr.release();
275
276  return ERR(NONE);
277}
278
279}  // namespace openjdkjvmti
280