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      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 "common_throws.h"
     18 #include "debugger.h"
     19 #include "jni_internal.h"
     20 #include "monitor.h"
     21 #include "mirror/object.h"
     22 #include "scoped_fast_native_object_access.h"
     23 #include "scoped_thread_state_change.h"
     24 #include "ScopedUtfChars.h"
     25 #include "thread.h"
     26 #include "thread_list.h"
     27 #include "verify_object-inl.h"
     28 
     29 namespace art {
     30 
     31 static jobject Thread_currentThread(JNIEnv* env, jclass) {
     32   ScopedFastNativeObjectAccess soa(env);
     33   return soa.AddLocalReference<jobject>(soa.Self()->GetPeer());
     34 }
     35 
     36 static jboolean Thread_interrupted(JNIEnv* env, jclass) {
     37   return static_cast<JNIEnvExt*>(env)->self->Interrupted() ? JNI_TRUE : JNI_FALSE;
     38 }
     39 
     40 static jboolean Thread_isInterrupted(JNIEnv* env, jobject java_thread) {
     41   ScopedFastNativeObjectAccess soa(env);
     42   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
     43   Thread* thread = Thread::FromManagedThread(soa, java_thread);
     44   return (thread != NULL) ? thread->IsInterrupted() : JNI_FALSE;
     45 }
     46 
     47 static void Thread_nativeCreate(JNIEnv* env, jclass, jobject java_thread, jlong stack_size,
     48                                 jboolean daemon) {
     49   Thread::CreateNativeThread(env, java_thread, stack_size, daemon == JNI_TRUE);
     50 }
     51 
     52 static jint Thread_nativeGetStatus(JNIEnv* env, jobject java_thread, jboolean has_been_started) {
     53   // Ordinals from Java's Thread.State.
     54   const jint kJavaNew = 0;
     55   const jint kJavaRunnable = 1;
     56   const jint kJavaBlocked = 2;
     57   const jint kJavaWaiting = 3;
     58   const jint kJavaTimedWaiting = 4;
     59   const jint kJavaTerminated = 5;
     60 
     61   ScopedObjectAccess soa(env);
     62   ThreadState internal_thread_state = (has_been_started ? kTerminated : kStarting);
     63   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
     64   Thread* thread = Thread::FromManagedThread(soa, java_thread);
     65   if (thread != NULL) {
     66     internal_thread_state = thread->GetState();
     67   }
     68   switch (internal_thread_state) {
     69     case kTerminated:                     return kJavaTerminated;
     70     case kRunnable:                       return kJavaRunnable;
     71     case kTimedWaiting:                   return kJavaTimedWaiting;
     72     case kSleeping:                       return kJavaTimedWaiting;
     73     case kBlocked:                        return kJavaBlocked;
     74     case kWaiting:                        return kJavaWaiting;
     75     case kStarting:                       return kJavaNew;
     76     case kNative:                         return kJavaRunnable;
     77     case kWaitingForGcToComplete:         return kJavaWaiting;
     78     case kWaitingPerformingGc:            return kJavaWaiting;
     79     case kWaitingForCheckPointsToRun:     return kJavaWaiting;
     80     case kWaitingForDebuggerSend:         return kJavaWaiting;
     81     case kWaitingForDebuggerToAttach:     return kJavaWaiting;
     82     case kWaitingInMainDebuggerLoop:      return kJavaWaiting;
     83     case kWaitingForDebuggerSuspension:   return kJavaWaiting;
     84     case kWaitingForDeoptimization:       return kJavaWaiting;
     85     case kWaitingForJniOnLoad:            return kJavaWaiting;
     86     case kWaitingForSignalCatcherOutput:  return kJavaWaiting;
     87     case kWaitingInMainSignalCatcherLoop: return kJavaWaiting;
     88     case kWaitingForMethodTracingStart:   return kJavaWaiting;
     89     case kSuspended:                      return kJavaRunnable;
     90     // Don't add a 'default' here so the compiler can spot incompatible enum changes.
     91   }
     92   LOG(ERROR) << "Unexpected thread state: " << internal_thread_state;
     93   return -1;  // Unreachable.
     94 }
     95 
     96 static jboolean Thread_nativeHoldsLock(JNIEnv* env, jobject java_thread, jobject java_object) {
     97   ScopedObjectAccess soa(env);
     98   mirror::Object* object = soa.Decode<mirror::Object*>(java_object);
     99   if (object == NULL) {
    100     ThrowNullPointerException(NULL, "object == null");
    101     return JNI_FALSE;
    102   }
    103   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
    104   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    105   return thread->HoldsLock(object);
    106 }
    107 
    108 static void Thread_nativeInterrupt(JNIEnv* env, jobject java_thread) {
    109   ScopedFastNativeObjectAccess soa(env);
    110   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
    111   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    112   if (thread != NULL) {
    113     thread->Interrupt(soa.Self());
    114   }
    115 }
    116 
    117 static void Thread_nativeSetName(JNIEnv* env, jobject peer, jstring java_name) {
    118   ScopedUtfChars name(env, java_name);
    119   Thread* self;
    120   {
    121     ScopedObjectAccess soa(env);
    122     if (soa.Decode<mirror::Object*>(peer) == soa.Self()->GetPeer()) {
    123       soa.Self()->SetThreadName(name.c_str());
    124       return;
    125     }
    126     self = soa.Self();
    127   }
    128   // Suspend thread to avoid it from killing itself while we set its name. We don't just hold the
    129   // thread list lock to avoid this, as setting the thread name causes mutator to lock/unlock
    130   // in the DDMS send code.
    131   ThreadList* thread_list = Runtime::Current()->GetThreadList();
    132   bool timed_out;
    133   // Take suspend thread lock to avoid races with threads trying to suspend this one.
    134   Thread* thread;
    135   {
    136     MutexLock mu(self, *Locks::thread_list_suspend_thread_lock_);
    137     thread = thread_list->SuspendThreadByPeer(peer, true, false, &timed_out);
    138   }
    139   if (thread != NULL) {
    140     {
    141       ScopedObjectAccess soa(env);
    142       thread->SetThreadName(name.c_str());
    143     }
    144     thread_list->Resume(thread, false);
    145   } else if (timed_out) {
    146     LOG(ERROR) << "Trying to set thread name to '" << name.c_str() << "' failed as the thread "
    147         "failed to suspend within a generous timeout.";
    148   }
    149 }
    150 
    151 /*
    152  * Alter the priority of the specified thread.  "new_priority" will range
    153  * from Thread.MIN_PRIORITY to Thread.MAX_PRIORITY (1-10), with "normal"
    154  * threads at Thread.NORM_PRIORITY (5).
    155  */
    156 static void Thread_nativeSetPriority(JNIEnv* env, jobject java_thread, jint new_priority) {
    157   ScopedObjectAccess soa(env);
    158   MutexLock mu(soa.Self(), *Locks::thread_list_lock_);
    159   Thread* thread = Thread::FromManagedThread(soa, java_thread);
    160   if (thread != NULL) {
    161     thread->SetNativePriority(new_priority);
    162   }
    163 }
    164 
    165 static void Thread_sleep(JNIEnv* env, jclass, jobject java_lock, jlong ms, jint ns) {
    166   ScopedFastNativeObjectAccess soa(env);
    167   mirror::Object* lock = soa.Decode<mirror::Object*>(java_lock);
    168   Monitor::Wait(Thread::Current(), lock, ms, ns, true, kSleeping);
    169 }
    170 
    171 /*
    172  * Causes the thread to temporarily pause and allow other threads to execute.
    173  *
    174  * The exact behavior is poorly defined.  Some discussion here:
    175  *   http://www.cs.umd.edu/~pugh/java/memoryModel/archive/0944.html
    176  */
    177 static void Thread_yield(JNIEnv*, jobject) {
    178   sched_yield();
    179 }
    180 
    181 static JNINativeMethod gMethods[] = {
    182   NATIVE_METHOD(Thread, currentThread, "!()Ljava/lang/Thread;"),
    183   NATIVE_METHOD(Thread, interrupted, "!()Z"),
    184   NATIVE_METHOD(Thread, isInterrupted, "!()Z"),
    185   NATIVE_METHOD(Thread, nativeCreate, "(Ljava/lang/Thread;JZ)V"),
    186   NATIVE_METHOD(Thread, nativeGetStatus, "(Z)I"),
    187   NATIVE_METHOD(Thread, nativeHoldsLock, "(Ljava/lang/Object;)Z"),
    188   NATIVE_METHOD(Thread, nativeInterrupt, "!()V"),
    189   NATIVE_METHOD(Thread, nativeSetName, "(Ljava/lang/String;)V"),
    190   NATIVE_METHOD(Thread, nativeSetPriority, "(I)V"),
    191   NATIVE_METHOD(Thread, sleep, "!(Ljava/lang/Object;JI)V"),
    192   NATIVE_METHOD(Thread, yield, "()V"),
    193 };
    194 
    195 void register_java_lang_Thread(JNIEnv* env) {
    196   REGISTER_NATIVE_METHODS("java/lang/Thread");
    197 }
    198 
    199 }  // namespace art
    200