java_lang_Thread.cc revision f38a6618b453b76a3370bbf6b351971687099388 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "java_lang_Thread.h"
18
19#include "common_throws.h"
20#include "jni_internal.h"
21#include "monitor.h"
22#include "mirror/object.h"
23#include "scoped_fast_native_object_access.h"
24#include "scoped_thread_state_change.h"
25#include "ScopedUtfChars.h"
26#include "thread.h"
27#include "thread_list.h"
28#include "verify_object-inl.h"
29
30namespace art {
31
32static jobject Thread_currentThread(JNIEnv* env, jclass) {
33  ScopedFastNativeObjectAccess soa(env);
34  return soa.AddLocalReference<jobject>(soa.Self()->GetPeer());
35}
36
37static jboolean Thread_interrupted(JNIEnv* env, jclass) {
38  return static_cast<JNIEnvExt*>(env)->self->Interrupted() ? JNI_TRUE : JNI_FALSE;
39}
40
41static jboolean Thread_isInterrupted(JNIEnv* env, jobject java_thread) {
42  ScopedFastNativeObjectAccess soa(env);
43  MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
44  Thread* thread = Thread::FromManagedThread(soa, java_thread);
45  return (thread != nullptr) ? thread->IsInterrupted() : JNI_FALSE;
46}
47
48static void Thread_nativeCreate(JNIEnv* env, jclass, jobject java_thread, jlong stack_size,
49                                jboolean daemon) {
50  // There are sections in the zygote that forbid thread creation.
51  Runtime* runtime = Runtime::Current();
52  if (runtime->IsZygote() && runtime->IsZygoteNoThreadSection()) {
53    jclass internal_error = env->FindClass("java/lang/InternalError");
54    CHECK(internal_error != nullptr);
55    env->ThrowNew(internal_error, "Cannot create threads in zygote");
56    return;
57  }
58
59  Thread::CreateNativeThread(env, java_thread, stack_size, daemon == JNI_TRUE);
60}
61
62static jint Thread_nativeGetStatus(JNIEnv* env, jobject java_thread, jboolean has_been_started) {
63  // Ordinals from Java's Thread.State.
64  const jint kJavaNew = 0;
65  const jint kJavaRunnable = 1;
66  const jint kJavaBlocked = 2;
67  const jint kJavaWaiting = 3;
68  const jint kJavaTimedWaiting = 4;
69  const jint kJavaTerminated = 5;
70
71  ScopedObjectAccess soa(env);
72  ThreadState internal_thread_state = (has_been_started ? kTerminated : kStarting);
73  MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
74  Thread* thread = Thread::FromManagedThread(soa, java_thread);
75  if (thread != nullptr) {
76    internal_thread_state = thread->GetState();
77  }
78  switch (internal_thread_state) {
79    case kTerminated:                     return kJavaTerminated;
80    case kRunnable:                       return kJavaRunnable;
81    case kTimedWaiting:                   return kJavaTimedWaiting;
82    case kSleeping:                       return kJavaTimedWaiting;
83    case kBlocked:                        return kJavaBlocked;
84    case kWaiting:                        return kJavaWaiting;
85    case kStarting:                       return kJavaNew;
86    case kNative:                         return kJavaRunnable;
87    case kWaitingForGcToComplete:         return kJavaWaiting;
88    case kWaitingPerformingGc:            return kJavaWaiting;
89    case kWaitingForCheckPointsToRun:     return kJavaWaiting;
90    case kWaitingForDebuggerSend:         return kJavaWaiting;
91    case kWaitingForDebuggerToAttach:     return kJavaWaiting;
92    case kWaitingInMainDebuggerLoop:      return kJavaWaiting;
93    case kWaitingForDebuggerSuspension:   return kJavaWaiting;
94    case kWaitingForDeoptimization:       return kJavaWaiting;
95    case kWaitingForGetObjectsAllocated:  return kJavaWaiting;
96    case kWaitingForJniOnLoad:            return kJavaWaiting;
97    case kWaitingForSignalCatcherOutput:  return kJavaWaiting;
98    case kWaitingInMainSignalCatcherLoop: return kJavaWaiting;
99    case kWaitingForMethodTracingStart:   return kJavaWaiting;
100    case kWaitingForVisitObjects:         return kJavaWaiting;
101    case kWaitingWeakGcRootRead:          return kJavaRunnable;
102    case kWaitingForGcThreadFlip:         return kJavaWaiting;
103    case kSuspended:                      return kJavaRunnable;
104    // Don't add a 'default' here so the compiler can spot incompatible enum changes.
105  }
106  LOG(ERROR) << "Unexpected thread state: " << internal_thread_state;
107  return -1;  // Unreachable.
108}
109
110static jboolean Thread_nativeHoldsLock(JNIEnv* env, jobject java_thread, jobject java_object) {
111  ScopedObjectAccess soa(env);
112  mirror::Object* object = soa.Decode<mirror::Object*>(java_object);
113  if (object == nullptr) {
114    ThrowNullPointerException("object == null");
115    return JNI_FALSE;
116  }
117  MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
118  Thread* thread = Thread::FromManagedThread(soa, java_thread);
119  return thread->HoldsLock(object);
120}
121
122static void Thread_nativeInterrupt(JNIEnv* env, jobject java_thread) {
123  ScopedFastNativeObjectAccess soa(env);
124  MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
125  Thread* thread = Thread::FromManagedThread(soa, java_thread);
126  if (thread != nullptr) {
127    thread->Interrupt(soa.Self());
128  }
129}
130
131static void Thread_nativeSetName(JNIEnv* env, jobject peer, jstring java_name) {
132  ScopedUtfChars name(env, java_name);
133  {
134    ScopedObjectAccess soa(env);
135    if (soa.Decode<mirror::Object*>(peer) == soa.Self()->GetPeer()) {
136      soa.Self()->SetThreadName(name.c_str());
137      return;
138    }
139  }
140  // Suspend thread to avoid it from killing itself while we set its name. We don't just hold the
141  // thread list lock to avoid this, as setting the thread name causes mutator to lock/unlock
142  // in the DDMS send code.
143  ThreadList* thread_list = Runtime::Current()->GetThreadList();
144  bool timed_out;
145  // Take suspend thread lock to avoid races with threads trying to suspend this one.
146  Thread* thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
147  if (thread != nullptr) {
148    {
149      ScopedObjectAccess soa(env);
150      thread->SetThreadName(name.c_str());
151    }
152    thread_list->Resume(thread, false);
153  } else if (timed_out) {
154    LOG(ERROR) << "Trying to set thread name to '" << name.c_str() << "' failed as the thread "
155        "failed to suspend within a generous timeout.";
156  }
157}
158
159/*
160 * Alter the priority of the specified thread.  "new_priority" will range
161 * from Thread.MIN_PRIORITY to Thread.MAX_PRIORITY (1-10), with "normal"
162 * threads at Thread.NORM_PRIORITY (5).
163 */
164static void Thread_nativeSetPriority(JNIEnv* env, jobject java_thread, jint new_priority) {
165  ScopedObjectAccess soa(env);
166  MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
167  Thread* thread = Thread::FromManagedThread(soa, java_thread);
168  if (thread != nullptr) {
169    thread->SetNativePriority(new_priority);
170  }
171}
172
173static void Thread_sleep(JNIEnv* env, jclass, jobject java_lock, jlong ms, jint ns) {
174  ScopedFastNativeObjectAccess soa(env);
175  mirror::Object* lock = soa.Decode<mirror::Object*>(java_lock);
176  Monitor::Wait(Thread::Current(), lock, ms, ns, true, kSleeping);
177}
178
179/*
180 * Causes the thread to temporarily pause and allow other threads to execute.
181 *
182 * The exact behavior is poorly defined.  Some discussion here:
183 *   http://www.cs.umd.edu/~pugh/java/memoryModel/archive/0944.html
184 */
185static void Thread_yield(JNIEnv*, jobject) {
186  sched_yield();
187}
188
189static JNINativeMethod gMethods[] = {
190  NATIVE_METHOD(Thread, currentThread, "!()Ljava/lang/Thread;"),
191  NATIVE_METHOD(Thread, interrupted, "!()Z"),
192  NATIVE_METHOD(Thread, isInterrupted, "!()Z"),
193  NATIVE_METHOD(Thread, nativeCreate, "(Ljava/lang/Thread;JZ)V"),
194  NATIVE_METHOD(Thread, nativeGetStatus, "(Z)I"),
195  NATIVE_METHOD(Thread, nativeHoldsLock, "(Ljava/lang/Object;)Z"),
196  NATIVE_METHOD(Thread, nativeInterrupt, "!()V"),
197  NATIVE_METHOD(Thread, nativeSetName, "(Ljava/lang/String;)V"),
198  NATIVE_METHOD(Thread, nativeSetPriority, "(I)V"),
199  NATIVE_METHOD(Thread, sleep, "!(Ljava/lang/Object;JI)V"),
200  NATIVE_METHOD(Thread, yield, "()V"),
201};
202
203void register_java_lang_Thread(JNIEnv* env) {
204  REGISTER_NATIVE_METHODS("java/lang/Thread");
205}
206
207}  // namespace art
208