replicant-frameworks_native/libs/utils/Threads.cpp
Eric Laurent a017d5b379 Fix issue 3302649.
The cause of the problem is that AudioTrack::start() can fail if it is called from a newly created
thread that has the same ID as the AudioTrack callback thread that has just been stopped and not yet exited.
This is possible as the thread ID used by the Thread class is not the TID.

The fix consists in clearing the thread ID before exiting the thread loop.

Change-Id: I66e679665c384403cb3ba2c31746f5de72d5836d
2011-01-04 11:58:04 -08:00

830 lines
24 KiB
C++

/*
* Copyright (C) 2007 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.
*/
// #define LOG_NDEBUG 0
#define LOG_TAG "libutils.threads"
#include <utils/threads.h>
#include <utils/Log.h>
#include <cutils/sched_policy.h>
#include <cutils/properties.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <errno.h>
#include <assert.h>
#include <unistd.h>
#if defined(HAVE_PTHREADS)
# include <pthread.h>
# include <sched.h>
# include <sys/resource.h>
#elif defined(HAVE_WIN32_THREADS)
# include <windows.h>
# include <stdint.h>
# include <process.h>
# define HAVE_CREATETHREAD // Cygwin, vs. HAVE__BEGINTHREADEX for MinGW
#endif
#if defined(HAVE_PRCTL)
#include <sys/prctl.h>
#endif
/*
* ===========================================================================
* Thread wrappers
* ===========================================================================
*/
using namespace android;
// ----------------------------------------------------------------------------
#if defined(HAVE_PTHREADS)
// ----------------------------------------------------------------------------
/*
* Create and run a new thread.
*
* We create it "detached", so it cleans up after itself.
*/
typedef void* (*android_pthread_entry)(void*);
static pthread_once_t gDoSchedulingGroupOnce = PTHREAD_ONCE_INIT;
static bool gDoSchedulingGroup = true;
static void checkDoSchedulingGroup(void) {
char buf[PROPERTY_VALUE_MAX];
int len = property_get("debug.sys.noschedgroups", buf, "");
if (len > 0) {
int temp;
if (sscanf(buf, "%d", &temp) == 1) {
gDoSchedulingGroup = temp == 0;
}
}
}
struct thread_data_t {
thread_func_t entryFunction;
void* userData;
int priority;
char * threadName;
// we use this trampoline when we need to set the priority with
// nice/setpriority.
static int trampoline(const thread_data_t* t) {
thread_func_t f = t->entryFunction;
void* u = t->userData;
int prio = t->priority;
char * name = t->threadName;
delete t;
setpriority(PRIO_PROCESS, 0, prio);
pthread_once(&gDoSchedulingGroupOnce, checkDoSchedulingGroup);
if (gDoSchedulingGroup) {
if (prio >= ANDROID_PRIORITY_BACKGROUND) {
set_sched_policy(androidGetTid(), SP_BACKGROUND);
} else {
set_sched_policy(androidGetTid(), SP_FOREGROUND);
}
}
if (name) {
#if defined(HAVE_PRCTL)
// Mac OS doesn't have this, and we build libutil for the host too
int hasAt = 0;
int hasDot = 0;
char *s = name;
while (*s) {
if (*s == '.') hasDot = 1;
else if (*s == '@') hasAt = 1;
s++;
}
int len = s - name;
if (len < 15 || hasAt || !hasDot) {
s = name;
} else {
s = name + len - 15;
}
prctl(PR_SET_NAME, (unsigned long) s, 0, 0, 0);
#endif
free(name);
}
return f(u);
}
};
int androidCreateRawThreadEtc(android_thread_func_t entryFunction,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId)
{
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
#ifdef HAVE_ANDROID_OS /* valgrind is rejecting RT-priority create reqs */
if (threadPriority != PRIORITY_DEFAULT || threadName != NULL) {
// We could avoid the trampoline if there was a way to get to the
// android_thread_id_t (pid) from pthread_t
thread_data_t* t = new thread_data_t;
t->priority = threadPriority;
t->threadName = threadName ? strdup(threadName) : NULL;
t->entryFunction = entryFunction;
t->userData = userData;
entryFunction = (android_thread_func_t)&thread_data_t::trampoline;
userData = t;
}
#endif
if (threadStackSize) {
pthread_attr_setstacksize(&attr, threadStackSize);
}
errno = 0;
pthread_t thread;
int result = pthread_create(&thread, &attr,
(android_pthread_entry)entryFunction, userData);
if (result != 0) {
LOGE("androidCreateRawThreadEtc failed (entry=%p, res=%d, errno=%d)\n"
"(android threadPriority=%d)",
entryFunction, result, errno, threadPriority);
return 0;
}
if (threadId != NULL) {
*threadId = (android_thread_id_t)thread; // XXX: this is not portable
}
return 1;
}
android_thread_id_t androidGetThreadId()
{
return (android_thread_id_t)pthread_self();
}
// ----------------------------------------------------------------------------
#elif defined(HAVE_WIN32_THREADS)
// ----------------------------------------------------------------------------
/*
* Trampoline to make us __stdcall-compliant.
*
* We're expected to delete "vDetails" when we're done.
*/
struct threadDetails {
int (*func)(void*);
void* arg;
};
static __stdcall unsigned int threadIntermediary(void* vDetails)
{
struct threadDetails* pDetails = (struct threadDetails*) vDetails;
int result;
result = (*(pDetails->func))(pDetails->arg);
delete pDetails;
LOG(LOG_VERBOSE, "thread", "thread exiting\n");
return (unsigned int) result;
}
/*
* Create and run a new thread.
*/
static bool doCreateThread(android_thread_func_t fn, void* arg, android_thread_id_t *id)
{
HANDLE hThread;
struct threadDetails* pDetails = new threadDetails; // must be on heap
unsigned int thrdaddr;
pDetails->func = fn;
pDetails->arg = arg;
#if defined(HAVE__BEGINTHREADEX)
hThread = (HANDLE) _beginthreadex(NULL, 0, threadIntermediary, pDetails, 0,
&thrdaddr);
if (hThread == 0)
#elif defined(HAVE_CREATETHREAD)
hThread = CreateThread(NULL, 0,
(LPTHREAD_START_ROUTINE) threadIntermediary,
(void*) pDetails, 0, (DWORD*) &thrdaddr);
if (hThread == NULL)
#endif
{
LOG(LOG_WARN, "thread", "WARNING: thread create failed\n");
return false;
}
#if defined(HAVE_CREATETHREAD)
/* close the management handle */
CloseHandle(hThread);
#endif
if (id != NULL) {
*id = (android_thread_id_t)thrdaddr;
}
return true;
}
int androidCreateRawThreadEtc(android_thread_func_t fn,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId)
{
return doCreateThread( fn, userData, threadId);
}
android_thread_id_t androidGetThreadId()
{
return (android_thread_id_t)GetCurrentThreadId();
}
// ----------------------------------------------------------------------------
#else
#error "Threads not supported"
#endif
// ----------------------------------------------------------------------------
int androidCreateThread(android_thread_func_t fn, void* arg)
{
return createThreadEtc(fn, arg);
}
int androidCreateThreadGetID(android_thread_func_t fn, void *arg, android_thread_id_t *id)
{
return createThreadEtc(fn, arg, "android:unnamed_thread",
PRIORITY_DEFAULT, 0, id);
}
static android_create_thread_fn gCreateThreadFn = androidCreateRawThreadEtc;
int androidCreateThreadEtc(android_thread_func_t entryFunction,
void *userData,
const char* threadName,
int32_t threadPriority,
size_t threadStackSize,
android_thread_id_t *threadId)
{
return gCreateThreadFn(entryFunction, userData, threadName,
threadPriority, threadStackSize, threadId);
}
void androidSetCreateThreadFunc(android_create_thread_fn func)
{
gCreateThreadFn = func;
}
pid_t androidGetTid()
{
#ifdef HAVE_GETTID
return gettid();
#else
return getpid();
#endif
}
int androidSetThreadSchedulingGroup(pid_t tid, int grp)
{
if (grp > ANDROID_TGROUP_MAX || grp < 0) {
return BAD_VALUE;
}
#if defined(HAVE_PTHREADS)
pthread_once(&gDoSchedulingGroupOnce, checkDoSchedulingGroup);
if (gDoSchedulingGroup) {
if (set_sched_policy(tid, (grp == ANDROID_TGROUP_BG_NONINTERACT) ?
SP_BACKGROUND : SP_FOREGROUND)) {
return PERMISSION_DENIED;
}
}
#endif
return NO_ERROR;
}
int androidSetThreadPriority(pid_t tid, int pri)
{
int rc = 0;
#if defined(HAVE_PTHREADS)
int lasterr = 0;
pthread_once(&gDoSchedulingGroupOnce, checkDoSchedulingGroup);
if (gDoSchedulingGroup) {
if (pri >= ANDROID_PRIORITY_BACKGROUND) {
rc = set_sched_policy(tid, SP_BACKGROUND);
} else if (getpriority(PRIO_PROCESS, tid) >= ANDROID_PRIORITY_BACKGROUND) {
rc = set_sched_policy(tid, SP_FOREGROUND);
}
}
if (rc) {
lasterr = errno;
}
if (setpriority(PRIO_PROCESS, tid, pri) < 0) {
rc = INVALID_OPERATION;
} else {
errno = lasterr;
}
#endif
return rc;
}
namespace android {
/*
* ===========================================================================
* Mutex class
* ===========================================================================
*/
#if defined(HAVE_PTHREADS)
// implemented as inlines in threads.h
#elif defined(HAVE_WIN32_THREADS)
Mutex::Mutex()
{
HANDLE hMutex;
assert(sizeof(hMutex) == sizeof(mState));
hMutex = CreateMutex(NULL, FALSE, NULL);
mState = (void*) hMutex;
}
Mutex::Mutex(const char* name)
{
// XXX: name not used for now
HANDLE hMutex;
assert(sizeof(hMutex) == sizeof(mState));
hMutex = CreateMutex(NULL, FALSE, NULL);
mState = (void*) hMutex;
}
Mutex::Mutex(int type, const char* name)
{
// XXX: type and name not used for now
HANDLE hMutex;
assert(sizeof(hMutex) == sizeof(mState));
hMutex = CreateMutex(NULL, FALSE, NULL);
mState = (void*) hMutex;
}
Mutex::~Mutex()
{
CloseHandle((HANDLE) mState);
}
status_t Mutex::lock()
{
DWORD dwWaitResult;
dwWaitResult = WaitForSingleObject((HANDLE) mState, INFINITE);
return dwWaitResult != WAIT_OBJECT_0 ? -1 : NO_ERROR;
}
void Mutex::unlock()
{
if (!ReleaseMutex((HANDLE) mState))
LOG(LOG_WARN, "thread", "WARNING: bad result from unlocking mutex\n");
}
status_t Mutex::tryLock()
{
DWORD dwWaitResult;
dwWaitResult = WaitForSingleObject((HANDLE) mState, 0);
if (dwWaitResult != WAIT_OBJECT_0 && dwWaitResult != WAIT_TIMEOUT)
LOG(LOG_WARN, "thread", "WARNING: bad result from try-locking mutex\n");
return (dwWaitResult == WAIT_OBJECT_0) ? 0 : -1;
}
#else
#error "Somebody forgot to implement threads for this platform."
#endif
/*
* ===========================================================================
* Condition class
* ===========================================================================
*/
#if defined(HAVE_PTHREADS)
// implemented as inlines in threads.h
#elif defined(HAVE_WIN32_THREADS)
/*
* Windows doesn't have a condition variable solution. It's possible
* to create one, but it's easy to get it wrong. For a discussion, and
* the origin of this implementation, see:
*
* http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
*
* The implementation shown on the page does NOT follow POSIX semantics.
* As an optimization they require acquiring the external mutex before
* calling signal() and broadcast(), whereas POSIX only requires grabbing
* it before calling wait(). The implementation here has been un-optimized
* to have the correct behavior.
*/
typedef struct WinCondition {
// Number of waiting threads.
int waitersCount;
// Serialize access to waitersCount.
CRITICAL_SECTION waitersCountLock;
// Semaphore used to queue up threads waiting for the condition to
// become signaled.
HANDLE sema;
// An auto-reset event used by the broadcast/signal thread to wait
// for all the waiting thread(s) to wake up and be released from
// the semaphore.
HANDLE waitersDone;
// This mutex wouldn't be necessary if we required that the caller
// lock the external mutex before calling signal() and broadcast().
// I'm trying to mimic pthread semantics though.
HANDLE internalMutex;
// Keeps track of whether we were broadcasting or signaling. This
// allows us to optimize the code if we're just signaling.
bool wasBroadcast;
status_t wait(WinCondition* condState, HANDLE hMutex, nsecs_t* abstime)
{
// Increment the wait count, avoiding race conditions.
EnterCriticalSection(&condState->waitersCountLock);
condState->waitersCount++;
//printf("+++ wait: incr waitersCount to %d (tid=%ld)\n",
// condState->waitersCount, getThreadId());
LeaveCriticalSection(&condState->waitersCountLock);
DWORD timeout = INFINITE;
if (abstime) {
nsecs_t reltime = *abstime - systemTime();
if (reltime < 0)
reltime = 0;
timeout = reltime/1000000;
}
// Atomically release the external mutex and wait on the semaphore.
DWORD res =
SignalObjectAndWait(hMutex, condState->sema, timeout, FALSE);
//printf("+++ wait: awake (tid=%ld)\n", getThreadId());
// Reacquire lock to avoid race conditions.
EnterCriticalSection(&condState->waitersCountLock);
// No longer waiting.
condState->waitersCount--;
// Check to see if we're the last waiter after a broadcast.
bool lastWaiter = (condState->wasBroadcast && condState->waitersCount == 0);
//printf("+++ wait: lastWaiter=%d (wasBc=%d wc=%d)\n",
// lastWaiter, condState->wasBroadcast, condState->waitersCount);
LeaveCriticalSection(&condState->waitersCountLock);
// If we're the last waiter thread during this particular broadcast
// then signal broadcast() that we're all awake. It'll drop the
// internal mutex.
if (lastWaiter) {
// Atomically signal the "waitersDone" event and wait until we
// can acquire the internal mutex. We want to do this in one step
// because it ensures that everybody is in the mutex FIFO before
// any thread has a chance to run. Without it, another thread
// could wake up, do work, and hop back in ahead of us.
SignalObjectAndWait(condState->waitersDone, condState->internalMutex,
INFINITE, FALSE);
} else {
// Grab the internal mutex.
WaitForSingleObject(condState->internalMutex, INFINITE);
}
// Release the internal and grab the external.
ReleaseMutex(condState->internalMutex);
WaitForSingleObject(hMutex, INFINITE);
return res == WAIT_OBJECT_0 ? NO_ERROR : -1;
}
} WinCondition;
/*
* Constructor. Set up the WinCondition stuff.
*/
Condition::Condition()
{
WinCondition* condState = new WinCondition;
condState->waitersCount = 0;
condState->wasBroadcast = false;
// semaphore: no security, initial value of 0
condState->sema = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
InitializeCriticalSection(&condState->waitersCountLock);
// auto-reset event, not signaled initially
condState->waitersDone = CreateEvent(NULL, FALSE, FALSE, NULL);
// used so we don't have to lock external mutex on signal/broadcast
condState->internalMutex = CreateMutex(NULL, FALSE, NULL);
mState = condState;
}
/*
* Destructor. Free Windows resources as well as our allocated storage.
*/
Condition::~Condition()
{
WinCondition* condState = (WinCondition*) mState;
if (condState != NULL) {
CloseHandle(condState->sema);
CloseHandle(condState->waitersDone);
delete condState;
}
}
status_t Condition::wait(Mutex& mutex)
{
WinCondition* condState = (WinCondition*) mState;
HANDLE hMutex = (HANDLE) mutex.mState;
return ((WinCondition*)mState)->wait(condState, hMutex, NULL);
}
status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime)
{
WinCondition* condState = (WinCondition*) mState;
HANDLE hMutex = (HANDLE) mutex.mState;
nsecs_t absTime = systemTime()+reltime;
return ((WinCondition*)mState)->wait(condState, hMutex, &absTime);
}
/*
* Signal the condition variable, allowing one thread to continue.
*/
void Condition::signal()
{
WinCondition* condState = (WinCondition*) mState;
// Lock the internal mutex. This ensures that we don't clash with
// broadcast().
WaitForSingleObject(condState->internalMutex, INFINITE);
EnterCriticalSection(&condState->waitersCountLock);
bool haveWaiters = (condState->waitersCount > 0);
LeaveCriticalSection(&condState->waitersCountLock);
// If no waiters, then this is a no-op. Otherwise, knock the semaphore
// down a notch.
if (haveWaiters)
ReleaseSemaphore(condState->sema, 1, 0);
// Release internal mutex.
ReleaseMutex(condState->internalMutex);
}
/*
* Signal the condition variable, allowing all threads to continue.
*
* First we have to wake up all threads waiting on the semaphore, then
* we wait until all of the threads have actually been woken before
* releasing the internal mutex. This ensures that all threads are woken.
*/
void Condition::broadcast()
{
WinCondition* condState = (WinCondition*) mState;
// Lock the internal mutex. This keeps the guys we're waking up
// from getting too far.
WaitForSingleObject(condState->internalMutex, INFINITE);
EnterCriticalSection(&condState->waitersCountLock);
bool haveWaiters = false;
if (condState->waitersCount > 0) {
haveWaiters = true;
condState->wasBroadcast = true;
}
if (haveWaiters) {
// Wake up all the waiters.
ReleaseSemaphore(condState->sema, condState->waitersCount, 0);
LeaveCriticalSection(&condState->waitersCountLock);
// Wait for all awakened threads to acquire the counting semaphore.
// The last guy who was waiting sets this.
WaitForSingleObject(condState->waitersDone, INFINITE);
// Reset wasBroadcast. (No crit section needed because nobody
// else can wake up to poke at it.)
condState->wasBroadcast = 0;
} else {
// nothing to do
LeaveCriticalSection(&condState->waitersCountLock);
}
// Release internal mutex.
ReleaseMutex(condState->internalMutex);
}
#else
#error "condition variables not supported on this platform"
#endif
// ----------------------------------------------------------------------------
/*
* This is our thread object!
*/
Thread::Thread(bool canCallJava)
: mCanCallJava(canCallJava),
mThread(thread_id_t(-1)),
mLock("Thread::mLock"),
mStatus(NO_ERROR),
mExitPending(false), mRunning(false)
{
}
Thread::~Thread()
{
}
status_t Thread::readyToRun()
{
return NO_ERROR;
}
status_t Thread::run(const char* name, int32_t priority, size_t stack)
{
Mutex::Autolock _l(mLock);
if (mRunning) {
// thread already started
return INVALID_OPERATION;
}
// reset status and exitPending to their default value, so we can
// try again after an error happened (either below, or in readyToRun())
mStatus = NO_ERROR;
mExitPending = false;
mThread = thread_id_t(-1);
// hold a strong reference on ourself
mHoldSelf = this;
mRunning = true;
bool res;
if (mCanCallJava) {
res = createThreadEtc(_threadLoop,
this, name, priority, stack, &mThread);
} else {
res = androidCreateRawThreadEtc(_threadLoop,
this, name, priority, stack, &mThread);
}
if (res == false) {
mStatus = UNKNOWN_ERROR; // something happened!
mRunning = false;
mThread = thread_id_t(-1);
mHoldSelf.clear(); // "this" may have gone away after this.
return UNKNOWN_ERROR;
}
// Do not refer to mStatus here: The thread is already running (may, in fact
// already have exited with a valid mStatus result). The NO_ERROR indication
// here merely indicates successfully starting the thread and does not
// imply successful termination/execution.
return NO_ERROR;
}
int Thread::_threadLoop(void* user)
{
Thread* const self = static_cast<Thread*>(user);
sp<Thread> strong(self->mHoldSelf);
wp<Thread> weak(strong);
self->mHoldSelf.clear();
#if HAVE_ANDROID_OS
// this is very useful for debugging with gdb
self->mTid = gettid();
#endif
bool first = true;
do {
bool result;
if (first) {
first = false;
self->mStatus = self->readyToRun();
result = (self->mStatus == NO_ERROR);
if (result && !self->mExitPending) {
// Binder threads (and maybe others) rely on threadLoop
// running at least once after a successful ::readyToRun()
// (unless, of course, the thread has already been asked to exit
// at that point).
// This is because threads are essentially used like this:
// (new ThreadSubclass())->run();
// The caller therefore does not retain a strong reference to
// the thread and the thread would simply disappear after the
// successful ::readyToRun() call instead of entering the
// threadLoop at least once.
result = self->threadLoop();
}
} else {
result = self->threadLoop();
}
if (result == false || self->mExitPending) {
self->mExitPending = true;
self->mLock.lock();
self->mRunning = false;
// clear thread ID so that requestExitAndWait() does not exit if
// called by a new thread using the same thread ID as this one.
self->mThread = thread_id_t(-1);
self->mThreadExitedCondition.broadcast();
self->mLock.unlock();
break;
}
// Release our strong reference, to let a chance to the thread
// to die a peaceful death.
strong.clear();
// And immediately, re-acquire a strong reference for the next loop
strong = weak.promote();
} while(strong != 0);
return 0;
}
void Thread::requestExit()
{
mExitPending = true;
}
status_t Thread::requestExitAndWait()
{
if (mThread == getThreadId()) {
LOGW(
"Thread (this=%p): don't call waitForExit() from this "
"Thread object's thread. It's a guaranteed deadlock!",
this);
return WOULD_BLOCK;
}
requestExit();
Mutex::Autolock _l(mLock);
while (mRunning == true) {
mThreadExitedCondition.wait(mLock);
}
mExitPending = false;
return mStatus;
}
bool Thread::exitPending() const
{
return mExitPending;
}
}; // namespace android