tclunixthrd.c

tcl是工具命令语言

/* 
 * tclUnixThrd.c --
 *
 *	This file implements the UNIX-specific thread support.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS:  @(#) tclUnixThrd.c 1.18 98/02/19 14:24:12
 */

#include "tclInt.h"
#include "tclPort.h"

#ifdef TCL_THREADS

#include "pthread.h"

typedef struct ThreadSpecificData {
    char	    	nabuf[16];
    struct tm   	gtbuf;
    struct tm   	ltbuf;
    struct {
	Tcl_DirEntry ent;
	char name[MAXNAMLEN+1];
    } rdbuf;
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

/*
 * masterLock is used to serialize creation of mutexes, condition
 * variables, and thread local storage.
 * This is the only place that can count on the ability to statically
 * initialize the mutex.
 */

static pthread_mutex_t masterLock = PTHREAD_MUTEX_INITIALIZER;

/*
 * initLock is used to serialize initialization and finalization
 * of Tcl.  It cannot use any dyamically allocated storage.
 */

static pthread_mutex_t initLock = PTHREAD_MUTEX_INITIALIZER;

/*
 * allocLock is used by Tcl's version of malloc for synchronization.
 * For obvious reasons, cannot use any dyamically allocated storage.
 */

static pthread_mutex_t allocLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t *allocLockPtr = &allocLock;

/*
 * These are for the critical sections inside this file.
 */

#define MASTER_LOCK	pthread_mutex_lock(&masterLock)
#define MASTER_UNLOCK	pthread_mutex_unlock(&masterLock)

#endif /* TCL_THREADS */


/*
 *----------------------------------------------------------------------
 *
 * Tcl_CreateThread --
 *
 *	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
Tcl_CreateThread(idPtr, proc, clientData, stackSize, flags)
    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 */
{
#ifdef TCL_THREADS
    pthread_attr_t attr;
    int result;

    pthread_attr_init(&attr);
    pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);

#ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
    if (stackSize != TCL_THREAD_STACK_DEFAULT) {
        pthread_attr_setstacksize(&attr, (size_t) stackSize);
#ifdef TCL_THREAD_STACK_MIN
    } else {
        /*
	 * Certain systems define a thread stack size that by default is
	 * too small for many operations.  The user has the option of
	 * defining TCL_THREAD_STACK_MIN to a value large enough to work
	 * for their needs.  This would look like (for 128K min stack):
	 *    make MEM_DEBUG_FLAGS=-DTCL_THREAD_STACK_MIN=131072L
	 *
	 * This solution is not optimal, as we should allow the user to
	 * specify a size at runtime, but we don't want to slow this function
	 * down, and that would still leave the main thread at the default.
	 */

        size_t size;
	result = pthread_attr_getstacksize(&attr, &size);
	if (!result && (size < TCL_THREAD_STACK_MIN)) {
	    pthread_attr_setstacksize(&attr, (size_t) TCL_THREAD_STACK_MIN);
	}
#endif
    }
#endif
    if (! (flags & TCL_THREAD_JOINABLE)) {
        pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
    }


    if (pthread_create((pthread_t *)idPtr, &attr,
	    (void * (*)())proc, (void *)clientData) &&
	    pthread_create((pthread_t *)idPtr, NULL,
		    (void * (*)())proc, (void *)clientData)) {
	result = TCL_ERROR;
    } else {
	result = TCL_OK;
    }
    pthread_attr_destroy(&attr);
    return result;
#else
    return TCL_ERROR;
#endif /* TCL_THREADS */
}

/*
 *----------------------------------------------------------------------
 *
 * 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(id, state)
    Tcl_ThreadId id;	/* Id of the thread to wait upon */
    int*     state;	/* Reference to the storage the result
			 * of the thread we wait upon will be
			 * written into. */
{
#ifdef TCL_THREADS
    int result;

    result = pthread_join ((pthread_t) id, (VOID**) state);
    return (result == 0) ? TCL_OK : TCL_ERROR;
#else
    return TCL_ERROR;
#endif
}

#ifdef TCL_THREADS
/*
 *----------------------------------------------------------------------
 *
 * TclpThreadExit --
 *
 *	This procedure terminates the current thread.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	This procedure terminates the current thread.
 *
 *----------------------------------------------------------------------
 */

void
TclpThreadExit(status)
    int status;
{
    pthread_exit((VOID *)status);
}
#endif /* TCL_THREADS */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCurrentThread --
 *
 *	This procedure returns the ID of the currently running thread.
 *
 * Results:
 *	A thread ID.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_ThreadId
Tcl_GetCurrentThread()
{
#ifdef TCL_THREADS
    return (Tcl_ThreadId) pthread_self();
#else
    return (Tcl_ThreadId) 0;
#endif
}


/*
 *----------------------------------------------------------------------
 *
 * 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()
{
#ifdef TCL_THREADS
    pthread_mutex_lock(&initLock);
#endif
}


/*
 *----------------------------------------------------------------------
 *
 * 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()
{
#ifdef TCL_THREADS
    pthread_mutex_unlock(&initLock);
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclpMasterLock
 *
 *	This procedure is used to grab a lock that serializes creation
 *	and finalization of serialization objects.  This interface is
 *	only needed in finalization; it is hidden during
 *	creation of the objects.
 *
 *	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()
{
#ifdef TCL_THREADS
    pthread_mutex_lock(&masterLock);
#endif
}


/*
 *----------------------------------------------------------------------
 *
 * TclpMasterUnlock
 *
 *	This procedure is used to release a lock that serializes creation
 *	and finalization of synchronization objects.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Release the master mutex.
 *
 *----------------------------------------------------------------------
 */

void
TclpMasterUnlock()
{
#ifdef TCL_THREADS
    pthread_mutex_unlock(&masterLock);
#endif
}


/*
 *----------------------------------------------------------------------
 *
 * 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()
{
#ifdef TCL_THREADS
    return (Tcl_Mutex *)&allocLockPtr;
#else
    return NULL;
#endif
}

#ifdef TCL_THREADS

/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexLock --
 *
 *	This procedure is invoked to lock a mutex.  This procedure
 *	handles initializing the mutex, if necessary.  The caller
 *	can rely on the fact that Tcl_Mutex is an opaque pointer.
 *	This routine will change that pointer from NULL after first use.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May block the current thread.  The mutex is aquired when
 *	this returns.  Will allocate memory for a pthread_mutex_t
 *	and initialize this the first time this Tcl_Mutex is used.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexLock(mutexPtr)
    Tcl_Mutex *mutexPtr;	/* Really (pthread_mutex_t **) */
{
    pthread_mutex_t *pmutexPtr;
    if (*mutexPtr == NULL) {
	MASTER_LOCK;
	if (*mutexPtr == NULL) {
	    /* 
	     * Double inside master lock check to avoid a race condition.
	     */
    
	    pmutexPtr = (pthread_mutex_t *)ckalloc(sizeof(pthread_mutex_t));
	    pthread_mutex_init(pmutexPtr, NULL);
	    *mutexPtr = (Tcl_Mutex)pmutexPtr;
	    TclRememberMutex(mutexPtr);
	}
	MASTER_UNLOCK;
    }
    pmutexPtr = *((pthread_mutex_t **)mutexPtr);
    pthread_mutex_lock(pmutexPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_MutexUnlock --
 *
 *	This procedure is invoked to unlock a mutex.  The mutex must
 *	have been locked by Tcl_MutexLock.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex is released when this returns.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_MutexUnlock(mutexPtr)
    Tcl_Mutex *mutexPtr;	/* Really (pthread_mutex_t **) */
{
    pthread_mutex_t *pmutexPtr = *(pthread_mutex_t **)mutexPtr;
    pthread_mutex_unlock(pmutexPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * TclpFinalizeMutex --
 *
 *	This procedure is invoked to clean up one mutex.  This is only
 *	safe to call at the end of time.
 *
 *	This assumes the Master Lock is held.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The mutex list is deallocated.
 *
 *----------------------------------------------------------------------
 */

void
TclpFinalizeMutex(mutexPtr)
    Tcl_Mutex *mutexPtr;
{
    pthread_mutex_t *pmutexPtr = *(pthread_mutex_t **)mutexPtr;
    if (pmutexPtr != NULL) {
	ckfree((char *)pmutexPtr);
	*mutexPtr = NULL;
    }
}


/*
 *----------------------------------------------------------------------