/*
* tclWinThread.c --
*
* This file implements the Windows-specific thread operations.
*
* Copyright (c) 1998 by Sun Microsystems, Inc.
* Copyright (c) 1999 by Scriptics Corporation
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tclWinThrd.c,v 1.43.4.2 2010/01/31 23:51:37 nijtmans Exp $
*/
#include "tclWinInt.h"
#include <sys/stat.h>
/*
* This is the master lock used to serialize access to other serialization
* data structures.
*/
static CRITICAL_SECTION masterLock;
static int init = 0;
#define MASTER_LOCK TclpMasterLock()
#define MASTER_UNLOCK TclpMasterUnlock()
/*
* This is the master lock used to serialize initialization and finalization
* of Tcl as a whole.
*/
static CRITICAL_SECTION initLock;
/*
* allocLock is used by Tcl's version of malloc for synchronization. For
* obvious reasons, cannot use any dyamically allocated storage.
*/
#ifdef TCL_THREADS
static struct Tcl_Mutex_ {
CRITICAL_SECTION crit;
} allocLock;
static Tcl_Mutex allocLockPtr = &allocLock;
static int allocOnce = 0;
#endif /* TCL_THREADS */
/*
* The joinLock serializes Create- and ExitThread. This is necessary to
* prevent a race where a new joinable thread exits before the creating thread
* had the time to create the necessary data structures in the emulation
* layer.
*/
static CRITICAL_SECTION joinLock;
/*
* Condition variables are implemented with a combination of a per-thread
* Windows Event and a per-condition waiting queue. The idea is that each
* thread has its own Event that it waits on when it is doing a ConditionWait;
* it uses the same event for all condition variables because it only waits on
* one at a time. Each condition variable has a queue of waiting threads, and
* a mutex used to serialize access to this queue.
*
* Special thanks to David Nichols and Jim Davidson for advice on the
* Condition Variable implementation.
*/
/*
* The per-thread event and queue pointers.
*/
#ifdef TCL_THREADS
typedef struct ThreadSpecificData {
HANDLE condEvent; /* Per-thread condition event */
struct ThreadSpecificData *nextPtr; /* Queue pointers */
struct ThreadSpecificData *prevPtr;
int flags; /* See flags below */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;
#endif /* TCL_THREADS */
/*
* State bits for the thread.
* WIN_THREAD_UNINIT Uninitialized. Must be zero because of the way
* ThreadSpecificData is created.
* WIN_THREAD_RUNNING Running, not waiting.
* WIN_THREAD_BLOCKED Waiting, or trying to wait.
*/
#define WIN_THREAD_UNINIT 0x0
#define WIN_THREAD_RUNNING 0x1
#define WIN_THREAD_BLOCKED 0x2
/*
* The per condition queue pointers and the Mutex used to serialize access to
* the queue.
*/
typedef struct WinCondition {
CRITICAL_SECTION condLock; /* Lock to serialize queuing on the
* condition. */
struct ThreadSpecificData *firstPtr; /* Queue pointers */
struct ThreadSpecificData *lastPtr;
} WinCondition;
/*
* Additions by AOL for specialized thread memory allocator.
*/
#ifdef USE_THREAD_ALLOC
static int once;
static DWORD tlsKey;
typedef struct allocMutex {
Tcl_Mutex tlock;
CRITICAL_SECTION wlock;
} allocMutex;
#endif /* USE_THREAD_ALLOC */
/*
*----------------------------------------------------------------------
*
* TclpThreadCreate --
*
* This procedure creates a new thread.
*
* Results:
* TCL_OK if the thread could be created. The thread ID is returned in a
* parameter.
*
* Side effects:
* A new thread is created.
*
*----------------------------------------------------------------------
*/
int
TclpThreadCreate(
Tcl_ThreadId *idPtr, /* Return, the ID of the thread. */
Tcl_ThreadCreateProc proc, /* Main() function of the thread. */
ClientData clientData, /* The one argument to Main(). */
int stackSize, /* Size of stack for the new thread. */
int flags) /* Flags controlling behaviour of the new
* thread. */
{
HANDLE tHandle;
EnterCriticalSection(&joinLock);
*idPtr = 0; /* must initialize as Tcl_Thread is a pointer and
* on WIN64 sizeof void* != sizeof unsigned
*/
#if defined(_MSC_VER) || defined(__MSVCRT__) || defined(__BORLANDC__)
tHandle = (HANDLE) _beginthreadex(NULL, (unsigned) stackSize, proc,
clientData, 0, (unsigned *)idPtr);
#else
tHandle = CreateThread(NULL, (DWORD) stackSize,
(LPTHREAD_START_ROUTINE) proc, (LPVOID) clientData,
(DWORD) 0, (LPDWORD)idPtr);
#endif
if (tHandle == NULL) {
LeaveCriticalSection(&joinLock);
return TCL_ERROR;
} else {
if (flags & TCL_THREAD_JOINABLE) {
TclRememberJoinableThread(*idPtr);
}
/*
* The only purpose of this is to decrement the reference count so the
* OS resources will be reaquired when the thread closes.
*/
CloseHandle(tHandle);
LeaveCriticalSection(&joinLock);
return TCL_OK;
}
}
/*
*----------------------------------------------------------------------
*
* Tcl_JoinThread --
*
* This procedure waits upon the exit of the specified thread.
*
* Results:
* TCL_OK if the wait was successful, TCL_ERROR else.
*
* Side effects:
* The result area is set to the exit code of the thread we
* waited upon.
*
*----------------------------------------------------------------------
*/
int
Tcl_JoinThread(
Tcl_ThreadId threadId, /* Id of the thread to wait upon */
int *result) /* Reference to the storage the result of the
* thread we wait upon will be written into. */
{
return TclJoinThread(threadId, result);
}
/*
*----------------------------------------------------------------------
*
* TclpThreadExit --
*
* This procedure terminates the current thread.
*
* Results:
* None.
*
* Side effects:
* This procedure terminates the current thread.
*
*----------------------------------------------------------------------
*/
void
TclpThreadExit(
int status)
{
EnterCriticalSection(&joinLock);
TclSignalExitThread(Tcl_GetCurrentThread(), status);
LeaveCriticalSection(&joinLock);
#if defined(_MSC_VER) || defined(__MSVCRT__) || defined(__BORLANDC__)
_endthreadex((unsigned) status);
#else
ExitThread((DWORD) status);
#endif
}
/*
*----------------------------------------------------------------------
*
* Tcl_GetCurrentThread --
*
* This procedure returns the ID of the currently running thread.
*
* Results:
* A thread ID.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
Tcl_ThreadId
Tcl_GetCurrentThread(void)
{
return (Tcl_ThreadId) GetCurrentThreadId();
}
/*
*----------------------------------------------------------------------
*
* TclpInitLock
*
* This procedure is used to grab a lock that serializes initialization
* and finalization of Tcl. On some platforms this may also initialize
* the mutex used to serialize creation of more mutexes and thread local
* storage keys.
*
* Results:
* None.
*
* Side effects:
* Acquire the initialization mutex.
*
*----------------------------------------------------------------------
*/
void
TclpInitLock(void)
{
if (!init) {
/*
* There is a fundamental race here that is solved by creating the
* first Tcl interpreter in a single threaded environment. Once the
* interpreter has been created, it is safe to create more threads
* that create interpreters in parallel.
*/
init = 1;
InitializeCriticalSection(&joinLock);
InitializeCriticalSection(&initLock);
InitializeCriticalSection(&masterLock);
}
EnterCriticalSection(&initLock);
}
/*
*----------------------------------------------------------------------
*
* TclpInitUnlock
*
* This procedure is used to release a lock that serializes
* initialization and finalization of Tcl.
*
* Results:
* None.
*
* Side effects:
* Release the initialization mutex.
*
*----------------------------------------------------------------------
*/
void
TclpInitUnlock(void)
{
LeaveCriticalSection(&initLock);
}
/*
*----------------------------------------------------------------------
*
* TclpMasterLock
*
* This procedure is used to grab a lock that serializes creation of
* mutexes, condition variables, and thread local storage keys.
*
* This lock must be different than the initLock because the initLock is
* held during creation of syncronization objects.
*
* Results:
* None.
*
* Side effects:
* Acquire the master mutex.
*
*----------------------------------------------------------------------
*/
void
TclpMasterLock(void)
{
if (!init) {
/*
* There is a fundamental race here that is solved by creating the
* first Tcl interpreter in a single threaded environment. Once the
* interpreter has been created, it is safe to create more threads
* that create interpreters in parallel.
*/
init = 1;
InitializeCriticalSection(&joinLock);
InitializeCriticalSection(&initLock);
InitializeCriticalSection(&masterLock);
}
EnterCriticalSection(&masterLock);
}
/*
*----------------------------------------------------------------------
*
* TclpMasterUnlock
*
* This procedure is used to release a lock that serializes creation and
* deletion of synchronization objects.
*
* Results:
* None.
*
* Side effects:
* Release the master mutex.
*
*----------------------------------------------------------------------
*/
void
TclpMasterUnlock(void)
{
LeaveCriticalSection(&masterLock);
}
/*
*----------------------------------------------------------------------
*
* Tcl_GetAllocMutex
*
* This procedure returns a pointer to a statically initialized mutex for
* use by the memory allocator. The alloctor must use this lock, because
* all other locks are allocated...
*
* Results:
* A pointer to a mutex that is suitable for passing to Tcl_MutexLock and
* Tcl_MutexUnlock.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
Tcl_Mutex *
Tcl_GetAllocMutex(void)
{
#ifdef TCL_THREADS
if (!allocOnce) {
InitializeCriticalSection(&allocLock.crit);
allocOnce = 1;
}
return &allocLockPtr;
#else
return NULL;
#endif
}
/*
*----------------------------------------------------------------------
*
* TclpFinalizeLock
*
* This procedure is used to destroy all private resources used in this
* file.
*
* Results:
* None.
*
* Side effects:
* Destroys everything private. TclpInitLock must be held entering this
* function.
*
*----------------------------------------------------------------------
*/
void
TclFinalizeLock(void)
{
MASTER_LOCK;
DeleteCriticalSection(&joinLock);
/*
* Destroy the critical section that we are holding!
*/
DeleteCriticalSection(&masterLock);
init = 0;
#ifdef TCL_THREADS
if (allocOnce) {
DeleteCriticalSection(&allocLock.crit);
allocOnce = 0;
}
#endif
LeaveCriticalSection(&initLock);
/*
* Destroy the critical section that we were holding.
*/
DeleteCriticalSection(&initLock);
}
#ifdef TCL_THREADS
/* locally used prototype */
static void FinalizeConditionEvent(ClientData data);
/*
*----------------------------------------------------------------------
*
* Tcl_MutexLock --
*
* This procedure is invoked to lock a mutex. This is a self initializing
* mutex that is automatically finalized during Tcl_Finalize.
*
* Results:
* None.
*
* Side effects:
* May block the current thread. The mutex is aquired when this returns.
*
*----------------------------------------------------------------------
*/
void
Tcl_MutexLock(
Tcl_Mutex *mutexPtr) /* The lock */
{
CRITICAL_SECTION *csPtr;
if (*mutexPtr == NULL) {
MASTER_LOCK;
/*
* Double inside master lock check to avoid a race.
*/
if (*mutexPtr == NULL) {
csPtr = (CRITICAL_SECTION *) ckalloc(sizeof(CRITICAL_SECTION));
InitializeCriticalSection(csPtr);
*mutexPtr = (Tcl_Mutex)csPtr;
TclRememberMutex(mutexPtr);
}
MASTER_UNLOCK;
}
csPtr = *((CRITICAL_SECTION **)mutexPtr);
EnterCriticalSection(csPtr);
}
/*
*----------------------------------------------------------------------
*
* Tcl_MutexUnlock --
*
* This procedure is invoked to unlock a mutex.
*
* Results:
* None.
*
* Side effects:
* The mutex is released when this returns.
*
*----------------------------------------------------------------------
*/
void
Tcl_MutexUnlock(
Tcl_Mutex *mutexPtr) /* The lock */
{
CRITICAL_SECTION *csPtr = *((CRITICAL_SECTION **)mutexPtr);
LeaveCriticalSection(csPtr);
}
/*
*----------------------------------------------------------------------
*
* TclpFinalizeMutex --
*
* This procedure is invoked to clean up one mutex. This is only safe to
* call at the end of time.
*
* Results:
* None.
*
* Side effects:
* The mutex list is deallocated.
*
*----------------------------------------------------------------------
*/
void
TclpFinalizeMutex(
Tcl_Mutex *mutexPtr)
{
CRITICAL_SECTION *csPtr = *(CRITICAL_SECTION **)mutexPtr;
if (csPtr != NULL) {
DeleteCriticalSection(csPtr);
ckfree((char *) csPtr);
*mutexPtr = NULL;
}
}
/*
*----------------------------------------------------------------------
*
* Tcl_ConditionWait --
*
* This procedure is invoked to wait on a condition variable. The mutex
* is atomically released as part of the wait, and automatically grabbed
* when the condition is signaled.
*
* The mutex must be held when this procedure is called.
*
* Results:
* None.
*
* Side effects:
* May block the current thread. The mutex is aquired when this returns.
* Will allocate memory for a HANDLE and initialize this the first time
* this Tcl_Condition is used.
*
*----------------------------------------------------------------------
*/
void
Tcl_ConditionWait(
Tcl_Condition *condPtr, /* Really (WinCondition **) */
Tcl_Mutex *mutexPtr, /* Really (CRITICAL_SECTION **) */
Tcl_Time *timePtr) /* Timeout on waiting period */
{
WinCondition *winCondPtr; /* Per-condition queue head */
CRITICAL_SECTION *csPtr; /* Caller's Mutex, after casting */
DWORD wtime; /* Windows time value */
int timeout; /* True if we got a timeout */
int doExit = 0; /* True if we need to do exit setup */
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
/*
* Self initialize the two parts of the condition. The per-condition and
* per-thread parts need to be handled independently.
*/
if (tsdPtr->flags == WIN_THREAD_UNINIT) {
MASTER_LOCK;
/*
* Create the per-thread event and queue pointers.
*/
if (tsdPtr->flags == WIN_THREAD_UNINIT) {
tsdPtr->condEvent = CreateEvent(NULL, TRUE /* manual reset */,
FALSE /* non signaled */, NULL);
tsdPtr->nextPtr = NULL;
tsdPtr->prevPtr = NULL;
tsdPtr->flags = WIN_THREAD_RUNNING;
doExit = 1;
}
MASTER_UNLOCK;
if (doExit) {
/*
* Create a per-thread exit handler to clean up the condEvent. We
* must be careful to do this outside the Master Lock because
* Tcl_CreateThreadExitHandler uses its own ThreadSpecificData,
* and initializing that may drop back into the Master Lock.
*/
Tcl_CreateThreadExitHandler(FinalizeConditionEvent,
(ClientData) tsdPtr);
}
}
if (*condPtr == NULL) {
MASTER_LOCK;
/*
* Initialize the per-condition queue pointers and Mutex.
*/
if (*condPtr == NULL) {
winCondPtr = (WinCondition *) ckalloc(sizeof(WinCondition));
InitializeCriticalSection(&winCondPtr->condLock);
winCondPtr->firstPtr = NULL;
winCondPtr->lastPtr = NULL;
*condPtr = (Tcl_Condition) winCondPtr;
TclRememberCondition(condPtr);
}
MASTER_UNLOCK;
}
csPtr = *((CRITICAL_SECTION **)mutexPtr);
winCondPtr = *((WinCondition **)condPtr);
if (timePtr == NULL) {
wtime = INFINITE;
} else {
wtime = timePtr->sec * 1000 + timePtr->usec / 1000;
}
/*
* Queue the thread on the condition, using the per-condition lock for
* serialization.
*/
tsdPtr->flags = WIN_THREAD_BLOCKED;
tsdPtr->nextPtr = NULL;
EnterCriticalSection(&winCondPtr->condLock);
tsdPtr->prevPtr = winCondPtr->lastPtr; /* A: */
winCondPtr->lastPtr = tsdPtr;
if (tsdPtr->prevPtr != NULL) {
tsdPtr->prevPtr->nextPtr = tsdPtr;
}
if (winCondPtr->firstPtr == NULL) {
winCondPtr->firstPtr = tsdPtr;
}
/*
* Unlock the caller's mutex and wait for the condition, or a timeout.
* There is a minor issue here in that we don't count down the timeout if
* we get notified, but another thread grabs the condition before we do.
* In that race condition we'll wait again for the full timeout. Timed
* waits are dubious anyway. Either you have the locking protocol wrong
* and are masking a deadlock, or you are using conditions to pause your
* thread.
*/
LeaveCriticalSection(csPtr);
timeout = 0;
while (!timeout && (tsdPtr->flags & WIN_THREAD_BLOCKED)) {
ResetEvent(tsdPtr->condEvent);
LeaveCriticalSection(&winCondPtr->condLock);
if (WaitForSingleObject(tsdPtr->condEvent, wtime) == WAIT_TIMEOUT) {
timeout = 1;
}
EnterCriticalSection(&winCondPtr->condLock);
}
/*
* Be careful on timeouts because the signal might arrive right around the
* time limit and someone else could have taken us off the queue.
*/
if (timeout) {
if (tsdPtr->flags & WIN_THREAD_RUNNING) {
timeout = 0;
} else {
/*
* When dequeuing, we can leave the tsdPtr->nextPtr and
* tsdPtr->prevPtr with dangling pointers because they are
* reinitialilzed w/out reading them when the thread is enqueued
* later.
*/
if (winCondPtr->firstPtr == tsdPtr) {
winCondPtr->firstPtr = tsdPtr->nextPtr;
} else {
tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
}
if (winCondPtr->lastPtr == tsdPtr) {
winCondPtr->lastPtr = tsdPtr->prevPtr;
} else {
tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
}
tsdPtr->flags = WIN_THREAD_RUNNING;
}
}
LeaveCriticalSection(&winCondPtr->condLock);
EnterCriticalSection(csPtr);
}
/*
*----------------------------------------------------------------------
*
* Tcl_ConditionNotify --
*
* This procedure is invoked to signal a condition variable.
*
* The mutex must be held during this call to avoid races, but this
* interface does not enforce that.
*
* Results:
* None.
*
* Side effects:
* May unblock another thread.
*
*----------------------------------------------------------------------
*/
void
Tcl_ConditionNotify(
Tcl_Condition *condPtr)
{
WinCondition *winCondPtr;
ThreadSpecificData *tsdPtr;
if (*condPtr != NULL) {
winCondPtr = *((WinCondition **)condPtr);
if (winCondPtr == NULL) {
return;
}
/*
* Loop through all the threads waiting on the condition and notify
* them (i.e., broadcast semantics). The queue manipulation is guarded
* by the per-condition coordinating mutex.
*/
EnterCriticalSection(&winCondPtr->condLock);
while (winCondPtr->firstPtr != NULL) {
tsdPtr = winCondPtr->firstPtr;
winCondPtr->firstPtr = tsdPtr->nextPtr;
if (winCondPtr->lastPtr == tsdPtr) {
winCondPtr->lastPtr = NULL;
}
tsdPtr->flags = WIN_THREAD_RUNNING;
tsdPtr->nextPtr = NULL;
tsdPtr->prevPtr = NULL; /* Not strictly necessary, see A: */
SetEvent(tsdPtr->condEvent);
}
LeaveCriticalSection(&winCondPtr->condLock);
} else {
/*
* No-one has used the condition variable, so there are no waiters.
*/
}
}
/*
*----------------------------------------------------------------------
*
* FinalizeConditionEvent --
*
* This procedure is invoked to clean up the per-thread event used to
* implement condition waiting. This is only safe to call at the end of
* time.
*
* Results:
* None.
*
* Side effects:
* The per-thread event is closed.
*
*----------------------------------------------------------------------
*/
static void
FinalizeConditionEvent(
ClientData data)
{
ThreadSpecificData *tsdPtr = (ThreadSpecificData *) data;
tsdPtr->flags = WIN_THREAD_UNINIT;
CloseHandle(tsdPtr->condEvent);
}
/*
*----------------------------------------------------------------------
*
* TclpFinalizeCondition --
*
* This procedure is invoked to clean up a condition variable. This is
* only safe to call at the end of time.
*
* This assumes the Master Lock is held.
*
* Results:
* None.
*
* Side effects:
* The condition variable is deallocated.
*
*----------------------------------------------------------------------
*/
void
TclpFinalizeCondition(
Tcl_Condition *condPtr)
{
WinCondition *winCondPtr = *(WinCondition **)condPtr;
/*
* Note - this is called long after the thread-local storage is reclaimed.
* The per-thread condition waiting event is reclaimed earlier in a
* per-thread exit handler, which is called before thread local storage is
* reclaimed.
*/
if (winCondPtr != NULL) {
DeleteCriticalSection(&winCondPtr->condLock);
ckfree((char *) winCondPtr);
*condPtr = NULL;
}
}
/*
* Additions by AOL for specialized thread memory allocator.
*/
#ifdef USE_THREAD_ALLOC
Tcl_Mutex *
TclpNewAllocMutex(void)
{
struct allocMutex *lockPtr;
lockPtr = malloc(sizeof(struct allocMutex));
if (lockPtr == NULL) {
Tcl_Panic("could not allocate lock");
}
lockPtr->tlock = (Tcl_Mutex) &lockPtr->wlock;
InitializeCriticalSection(&lockPtr->wlock);
return &lockPtr->tlock;
}
void
TclpFreeAllocMutex(
Tcl_Mutex *mutex) /* The alloc mutex to free. */
{
allocMutex *lockPtr = (allocMutex *) mutex;
if (!lockPtr) {
return;
}
DeleteCriticalSection(&lockPtr->wlock);
free(lockPtr);
}
void *
TclpGetAllocCache(void)
{
VOID *result;
if (!once) {
/*
* We need to make sure that TclpFreeAllocCache is called on each
* thread that calls this, but only on threads that call this.
*/
tlsKey = TlsAlloc();
once = 1;
if (tlsKey == TLS_OUT_OF_INDEXES) {
Tcl_Panic("could not allocate thread local storage");
}
}
result = TlsGetValue(tlsKey);
if ((result == NULL) && (GetLastError() != NO_ERROR)) {
Tcl_Panic("TlsGetValue failed from TclpGetAllocCache");
}
return result;
}
void
TclpSetAllocCache(
void *ptr)
{
BOOL success;
success = TlsSetValue(tlsKey, ptr);
if (!success) {
Tcl_Panic("TlsSetValue failed from TclpSetAllocCache");
}
}
void
TclpFreeAllocCache(
void *ptr)
{
BOOL success;
if (ptr != NULL) {
/*
* Called by us in TclpFinalizeThreadData when a thread exits and
* destroys the tsd key which stores allocator caches.
*/
TclFreeAllocCache(ptr);
success = TlsSetValue(tlsKey, NULL);
if (!success) {
Tcl_Panic("TlsSetValue failed from TclpFreeAllocCache");
}
} else if (once) {
/*
* Called by us in TclFinalizeThreadAlloc() during the library
* finalization initiated from Tcl_Finalize()
*/
success = TlsFree(tlsKey);
if (!success) {
Tcl_Panic("TlsFree failed from TclpFreeAllocCache");
}
once = 0; /* reset for next time. */
}
}
#endif /* USE_THREAD_ALLOC */
#endif /* TCL_THREADS */
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
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