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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mutex.h"
#include <errno.h>
#include "logging.h"
#include "runtime.h"
#include "thread.h"
#include "utils.h"
#define CHECK_MUTEX_CALL(call, args) CHECK_PTHREAD_CALL(call, args, name_)
namespace art {
// This works on Mac OS 10.7, but hasn't been tested on older releases.
struct __attribute__((__may_alias__)) darwin_pthread_mutex_t {
uint32_t padding0[2];
uint32_t value;
uint32_t padding1[5];
uint64_t owner_tid;
// ...other stuff we don't care about.
};
struct __attribute__((__may_alias__)) glibc_pthread_mutex_t {
int lock;
unsigned int count;
int owner;
// ...other stuff we don't care about.
};
static inline void CheckSafeToLockOrUnlock(MutexRank rank, bool is_locking) {
if (!kIsDebugBuild) {
return;
}
if (rank == -1) {
return;
}
Thread* self = Thread::Current();
if (self != NULL) {
self->CheckSafeToLockOrUnlock(rank, is_locking);
}
}
static inline void CheckSafeToWait(MutexRank rank) {
if (!kIsDebugBuild) {
return;
}
Thread* self = Thread::Current();
if (self != NULL) {
self->CheckSafeToWait(rank);
}
}
Mutex::Mutex(const char* name, MutexRank rank) : name_(name), rank_(rank) {
// Like Java, we use recursive mutexes.
pthread_mutexattr_t attributes;
CHECK_MUTEX_CALL(pthread_mutexattr_init, (&attributes));
CHECK_MUTEX_CALL(pthread_mutexattr_settype, (&attributes, PTHREAD_MUTEX_RECURSIVE));
CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, &attributes));
CHECK_MUTEX_CALL(pthread_mutexattr_destroy, (&attributes));
}
Mutex::~Mutex() {
int rc = pthread_mutex_destroy(&mutex_);
if (rc != 0) {
errno = rc;
// TODO: should we just not log at all if shutting down? this could be the logging mutex!
bool shutting_down = Runtime::Current()->IsShuttingDown();
PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
}
}
void Mutex::Lock() {
CheckSafeToLockOrUnlock(rank_, true);
CHECK_MUTEX_CALL(pthread_mutex_lock, (&mutex_));
AssertHeld();
}
bool Mutex::TryLock() {
int result = pthread_mutex_trylock(&mutex_);
if (result == EBUSY) {
return false;
}
if (result != 0) {
errno = result;
PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
}
CheckSafeToLockOrUnlock(rank_, true);
AssertHeld();
return true;
}
void Mutex::Unlock() {
AssertHeld();
CheckSafeToLockOrUnlock(rank_, false);
CHECK_MUTEX_CALL(pthread_mutex_unlock, (&mutex_));
}
#if !defined(NDEBUG)
#if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED < 1060
// Mac OS 10.5 didn't have anything we could implement GetTid() with. One thing we could try would
// be using pthread_t instead of the actual tid; this would be acceptable in most places, and more
// portable. 10.5 is already obsolete, though, so doing so would probably be all pain for no gain.
void Mutex::AssertHeld() {}
void Mutex::AssertNotHeld() {}
#else
void Mutex::AssertHeld() {
DCHECK_EQ(GetOwner(), static_cast<uint64_t>(GetTid()));
}
void Mutex::AssertNotHeld() {
DCHECK_NE(GetOwner(), static_cast<uint64_t>(GetTid()));
}
#endif
#endif
uint64_t Mutex::GetOwner() {
#if defined(__BIONIC__)
return static_cast<uint64_t>((mutex_.value >> 16) & 0xffff);
#elif defined(__GLIBC__)
return reinterpret_cast<glibc_pthread_mutex_t*>(&mutex_)->owner;
#elif defined(__APPLE__)
return reinterpret_cast<darwin_pthread_mutex_t*>(&mutex_)->owner_tid;
#else
#error unsupported C library
#endif
}
uint32_t Mutex::GetDepth() {
bool held = (GetOwner() == static_cast<uint64_t>(GetTid()));
if (!held) {
return 0;
}
uint32_t depth;
#if defined(__BIONIC__)
depth = static_cast<uint32_t>((mutex_.value >> 2) & 0x7ff) + 1;
#elif defined(__GLIBC__)
depth = reinterpret_cast<glibc_pthread_mutex_t*>(&mutex_)->count;
#elif defined(__APPLE__)
darwin_pthread_mutex_t* darwin_mutex = reinterpret_cast<darwin_pthread_mutex_t*>(&mutex_);
depth = ((darwin_mutex->value >> 16) & 0xffff);
#else
#error unsupported C library
#endif
CHECK_NE(depth, 0U) << "owner=" << GetOwner() << " tid=" << GetTid();
return depth;
}
ConditionVariable::ConditionVariable(const std::string& name) : name_(name) {
CHECK_MUTEX_CALL(pthread_cond_init, (&cond_, NULL));
}
ConditionVariable::~ConditionVariable() {
CHECK_MUTEX_CALL(pthread_cond_destroy, (&cond_));
}
void ConditionVariable::Broadcast() {
CHECK_MUTEX_CALL(pthread_cond_broadcast, (&cond_));
}
void ConditionVariable::Signal() {
CHECK_MUTEX_CALL(pthread_cond_signal, (&cond_));
}
void ConditionVariable::Wait(Mutex& mutex) {
CheckSafeToWait(mutex.rank_);
CHECK_MUTEX_CALL(pthread_cond_wait, (&cond_, &mutex.mutex_));
}
void ConditionVariable::TimedWait(Mutex& mutex, const timespec& ts) {
#ifdef HAVE_TIMEDWAIT_MONOTONIC
#define TIMEDWAIT pthread_cond_timedwait_monotonic
#else
#define TIMEDWAIT pthread_cond_timedwait
#endif
CheckSafeToWait(mutex.rank_);
int rc = TIMEDWAIT(&cond_, &mutex.mutex_, &ts);
if (rc != 0 && rc != ETIMEDOUT) {
errno = rc;
PLOG(FATAL) << "TimedWait failed for " << name_;
}
}
std::ostream& operator<<(std::ostream& os, const MutexRank& rhs) {
switch (rhs) {
case kHeapLock: os << "HeapLock"; break;
case kThreadListLock: os << "ThreadListLock"; break;
case kThreadSuspendCountLock: os << "ThreadSuspendCountLock"; break;
default: os << "MutexRank[" << static_cast<int>(rhs) << "]"; break;
}
return os;
}
} // namespace