ptthread.c

Netscape NSPR库源码

    }

done:
    rv = _PT_PTHREAD_ATTR_DESTROY(&tattr);
    PR_ASSERT(0 == rv);

    return thred;
}  /* _PR_CreateThread */

PR_IMPLEMENT(PRThread*) PR_CreateThread(
    PRThreadType type, void (*start)(void *arg), void *arg,
    PRThreadPriority priority, PRThreadScope scope,
    PRThreadState state, PRUint32 stackSize)
{
    return _PR_CreateThread(
        type, start, arg, priority, scope, state, stackSize, PR_FALSE);
} /* PR_CreateThread */

PR_IMPLEMENT(PRThread*) PR_CreateThreadGCAble(
    PRThreadType type, void (*start)(void *arg), void *arg, 
    PRThreadPriority priority, PRThreadScope scope,
    PRThreadState state, PRUint32 stackSize)
{
    return _PR_CreateThread(
        type, start, arg, priority, scope, state, stackSize, PR_TRUE);
}  /* PR_CreateThreadGCAble */

PR_IMPLEMENT(void*) GetExecutionEnvironment(PRThread *thred)
{
    return thred->environment;
}  /* GetExecutionEnvironment */
 
PR_IMPLEMENT(void) SetExecutionEnvironment(PRThread *thred, void *env)
{
    thred->environment = env;
}  /* SetExecutionEnvironment */

PR_IMPLEMENT(PRThread*) PR_AttachThread(
    PRThreadType type, PRThreadPriority priority, PRThreadStack *stack)
{
    return PR_GetCurrentThread();
}  /* PR_AttachThread */


PR_IMPLEMENT(PRStatus) PR_JoinThread(PRThread *thred)
{
    int rv = -1;
    void *result = NULL;
    PR_ASSERT(thred != NULL);

    if ((0xafafafaf == thred->state)
    || (PT_THREAD_DETACHED == (PT_THREAD_DETACHED & thred->state))
    || (PT_THREAD_FOREIGN == (PT_THREAD_FOREIGN & thred->state)))
    {
        /*
         * This might be a bad address, but if it isn't, the state should
         * either be an unjoinable thread or it's already had the object
         * deleted. However, the client that called join on a detached
         * thread deserves all the rath I can muster....
         */
        PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
        PR_LogPrint(
            "PR_JoinThread: 0x%X not joinable | already smashed\n", thred);
    }
    else
    {
        pthread_t id = thred->id;
        rv = pthread_join(id, &result);
        PR_ASSERT(rv == 0 && result == NULL);
        if (0 == rv)
        {
#ifdef _PR_DCETHREADS
            rv = pthread_detach(&id);
            PR_ASSERT(0 == rv);
#endif
            _pt_thread_death(thred);
        }
        else
        {
            PRErrorCode prerror;
            switch (rv)
            {
                case EINVAL:  /* not a joinable thread */
                case ESRCH:   /* no thread with given ID */
                    prerror = PR_INVALID_ARGUMENT_ERROR;
                    break;
                case EDEADLK: /* a thread joining with itself */
                    prerror = PR_DEADLOCK_ERROR;
                    break;
                default:
                    prerror = PR_UNKNOWN_ERROR;
                    break;
            }
            PR_SetError(prerror, rv);
        }
    }
    return (0 == rv) ? PR_SUCCESS : PR_FAILURE;
}  /* PR_JoinThread */

PR_IMPLEMENT(void) PR_DetachThread(void) { }  /* PR_DetachThread */

PR_IMPLEMENT(PRThread*) PR_GetCurrentThread(void)
{
    void *thred;

    if (!_pr_initialized) _PR_ImplicitInitialization();

    _PT_PTHREAD_GETSPECIFIC(pt_book.key, thred);
    if (NULL == thred) thred = pt_AttachThread();
    PR_ASSERT(NULL != thred);
    return (PRThread*)thred;
}  /* PR_GetCurrentThread */

PR_IMPLEMENT(PRThreadScope) PR_GetThreadScope(const PRThread *thred)
{
    return (thred->state & PT_THREAD_BOUND) ?
        PR_GLOBAL_BOUND_THREAD : PR_GLOBAL_THREAD;
}  /* PR_GetThreadScope() */

PR_IMPLEMENT(PRThreadType) PR_GetThreadType(const PRThread *thred)
{
    return (thred->state & PT_THREAD_SYSTEM) ?
        PR_SYSTEM_THREAD : PR_USER_THREAD;
}

PR_IMPLEMENT(PRThreadState) PR_GetThreadState(const PRThread *thred)
{
    return (thred->state & PT_THREAD_DETACHED) ?
        PR_UNJOINABLE_THREAD : PR_JOINABLE_THREAD;
}  /* PR_GetThreadState */

PR_IMPLEMENT(PRThreadPriority) PR_GetThreadPriority(const PRThread *thred)
{
    PR_ASSERT(thred != NULL);
    return thred->priority;
}  /* PR_GetThreadPriority */

PR_IMPLEMENT(void) PR_SetThreadPriority(PRThread *thred, PRThreadPriority newPri)
{
    PRIntn rv = -1;

    PR_ASSERT(NULL != thred);

    if ((PRIntn)PR_PRIORITY_FIRST > (PRIntn)newPri)
        newPri = PR_PRIORITY_FIRST;
    else if ((PRIntn)PR_PRIORITY_LAST < (PRIntn)newPri)
        newPri = PR_PRIORITY_LAST;

#if defined(_PR_DCETHREADS)
    rv = pthread_setprio(thred->id, pt_PriorityMap(newPri));
    /* pthread_setprio returns the old priority */
#elif defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
    if (EPERM != pt_schedpriv)
    {
        int policy;
        struct sched_param schedule;

        rv = pthread_getschedparam(thred->id, &policy, &schedule);
        if(0 == rv) {
			schedule.sched_priority = pt_PriorityMap(newPri);
			rv = pthread_setschedparam(thred->id, policy, &schedule);
			if (EPERM == rv)
			{
				pt_schedpriv = EPERM;
				PR_LOG(_pr_thread_lm, PR_LOG_MIN,
					("PR_SetThreadPriority: no thread scheduling privilege"));
			}
		}
		if (rv != 0)
			rv = -1;
    }
#endif

    thred->priority = newPri;
}  /* PR_SetThreadPriority */

PR_IMPLEMENT(PRStatus) PR_Interrupt(PRThread *thred)
{
    /*
    ** If the target thread indicates that it's waiting,
    ** find the condition and broadcast to it. Broadcast
    ** since we don't know which thread (if there are more
    ** than one). This sounds risky, but clients must
    ** test their invariants when resumed from a wait and
    ** I don't expect very many threads to be waiting on
    ** a single condition and I don't expect interrupt to
    ** be used very often.
    **
    ** I don't know why I thought this would work. Must have
    ** been one of those weaker momements after I'd been
    ** smelling the vapors.
    **
    ** Even with the followng changes it is possible that
    ** the pointer to the condition variable is pointing
    ** at a bogus value. Will the unerlying code detect
    ** that?
    */
    PRCondVar *cv;
    PR_ASSERT(NULL != thred);
    if (NULL == thred) return PR_FAILURE;

    thred->state |= PT_THREAD_ABORTED;

    cv = thred->waiting;
    if ((NULL != cv) && !thred->interrupt_blocked)
    {
        PRIntn rv;
        (void)PR_AtomicIncrement(&cv->notify_pending);
        rv = pthread_cond_broadcast(&cv->cv);
        PR_ASSERT(0 == rv);
        if (0 > PR_AtomicDecrement(&cv->notify_pending))
            PR_DestroyCondVar(cv);
    }
    return PR_SUCCESS;
}  /* PR_Interrupt */

PR_IMPLEMENT(void) PR_ClearInterrupt(void)
{
    PRThread *me = PR_CurrentThread();
    me->state &= ~PT_THREAD_ABORTED;
}  /* PR_ClearInterrupt */

PR_IMPLEMENT(void) PR_BlockInterrupt(void)
{
    PRThread *me = PR_CurrentThread();
    _PT_THREAD_BLOCK_INTERRUPT(me);
}  /* PR_BlockInterrupt */

PR_IMPLEMENT(void) PR_UnblockInterrupt(void)
{
    PRThread *me = PR_CurrentThread();
    _PT_THREAD_UNBLOCK_INTERRUPT(me);
}  /* PR_UnblockInterrupt */

PR_IMPLEMENT(PRStatus) PR_Yield(void)
{
    static PRBool warning = PR_TRUE;
    if (warning) warning = _PR_Obsolete(
        "PR_Yield()", "PR_Sleep(PR_INTERVAL_NO_WAIT)");
    return PR_Sleep(PR_INTERVAL_NO_WAIT);
}

PR_IMPLEMENT(PRStatus) PR_Sleep(PRIntervalTime ticks)
{
    PRStatus rv = PR_SUCCESS;

    if (!_pr_initialized) _PR_ImplicitInitialization();

    if (PR_INTERVAL_NO_WAIT == ticks)
    {
        _PT_PTHREAD_YIELD();
    }
    else
    {
        PRCondVar *cv;
        PRIntervalTime timein;

        timein = PR_IntervalNow();
        cv = PR_NewCondVar(_pr_sleeplock);
        PR_ASSERT(cv != NULL);
        PR_Lock(_pr_sleeplock);
        do
        {
            PRIntervalTime now = PR_IntervalNow();
            PRIntervalTime delta = now - timein;
            if (delta > ticks) break;
            rv = PR_WaitCondVar(cv, ticks - delta);
        } while (PR_SUCCESS == rv);
        PR_Unlock(_pr_sleeplock);
        PR_DestroyCondVar(cv);
    }
    return rv;
}  /* PR_Sleep */

static void _pt_thread_death(void *arg)
{
    PRThread *thred = (PRThread*)arg;

    if (thred->state & PT_THREAD_FOREIGN)
    {
        PR_Lock(pt_book.ml);
        thred->prev->next = thred->next;
        if (NULL == thred->next)
            pt_book.last = thred->prev;
        else
            thred->next->prev = thred->prev;
        PR_Unlock(pt_book.ml);
    }
    _PR_DestroyThreadPrivate(thred);
    PR_Free(thred->privateData);
    if (NULL != thred->errorString)
        PR_Free(thred->errorString);
    PR_Free(thred->stack);
    if (NULL != thred->syspoll_list)
        PR_Free(thred->syspoll_list);
#if defined(_PR_POLL_WITH_SELECT)
    if (NULL != thred->selectfd_list)
        PR_Free(thred->selectfd_list);
#endif
#if defined(DEBUG)
    memset(thred, 0xaf, sizeof(PRThread));
#endif /* defined(DEBUG) */
    PR_Free(thred);
}  /* _pt_thread_death */

void _PR_InitThreads(
    PRThreadType type, PRThreadPriority priority, PRUintn maxPTDs)
{
    int rv;
    PRThread *thred;

#ifdef _PR_NEED_PTHREAD_INIT
    /*
     * On BSD/OS (3.1 and 4.0), the pthread subsystem is lazily
     * initialized, but pthread_self() fails to initialize
     * pthreads and hence returns a null thread ID if invoked
     * by the primordial thread before any other pthread call.
     * So we explicitly initialize pthreads here.
     */
    pthread_init();
#endif

#if defined(_PR_DCETHREADS) || defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
#if defined(FREEBSD)
    {
    pthread_attr_t attr;
    int policy;
    /* get the min and max priorities of the default policy */
    pthread_attr_init(&attr);
    pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
    pthread_attr_getschedpolicy(&attr, &policy);
    pt_book.minPrio = sched_get_priority_min(policy);
    PR_ASSERT(-1 != pt_book.minPrio);
    pt_book.maxPrio = sched_get_priority_max(policy);
    PR_ASSERT(-1 != pt_book.maxPrio);
    pthread_attr_destroy(&attr);
    }
#else
    /*
    ** These might be function evaluations
    */
    pt_book.minPrio = PT_PRIO_MIN;
    pt_book.maxPrio = PT_PRIO_MAX;
#endif
#endif
    
    PR_ASSERT(NULL == pt_book.ml);
    pt_book.ml = PR_NewLock();
    PR_ASSERT(NULL != pt_book.ml);
    pt_book.cv = PR_NewCondVar(pt_book.ml);
    PR_ASSERT(NULL != pt_book.cv);
    thred = PR_NEWZAP(PRThread);
    PR_ASSERT(NULL != thred);
    thred->arg = NULL;
    thred->startFunc = NULL;
    thred->priority = priority;
    thred->id = pthread_self();

    thred->state = (PT_THREAD_DETACHED | PT_THREAD_PRIMORD);
    if (PR_SYSTEM_THREAD == type)
    {
        thred->state |= PT_THREAD_SYSTEM;
        pt_book.system += 1;
	    pt_book.this_many = 0;
    }
    else
    {
	    pt_book.user += 1;
	    pt_book.this_many = 1;
    }
    thred->next = thred->prev = NULL;
    pt_book.first = pt_book.last = thred;

    thred->stack = PR_NEWZAP(PRThreadStack);
    PR_ASSERT(thred->stack != NULL);
    thred->stack->stackSize = 0;
    thred->stack->thr = thred;
	_PR_InitializeStack(thred->stack);

    /*
     * Create a key for our use to store a backpointer in the pthread
     * to our PRThread object. This object gets deleted when the thread
     * returns from its root in the case of a detached thread. Other
     * threads delete the objects in Join.
     *
     * NB: The destructor logic seems to have a bug so it isn't used.
     * NBB: Oh really? I'm going to give it a spin - AOF 19 June 1998.
     * More info - the problem is that pthreads calls the destructor
     * eagerly as the thread returns from its root, rather than lazily
     * after the thread is joined. Therefore, threads that are joining
     * and holding PRThread references are actually holding pointers to
     * nothing.
     */
    rv = _PT_PTHREAD_KEY_CREATE(&pt_book.key, _pt_thread_death);
    PR_ASSERT(0 == rv);
    rv = pthread_setspecific(pt_book.key, thred);
    PR_ASSERT(0 == rv);    
    PR_SetThreadPriority(thred, priority);
}  /* _PR_InitThreads */

PR_IMPLEMENT(PRStatus) PR_Cleanup(void)
{
    PRThread *me = PR_CurrentThread();
    PR_LOG(_pr_thread_lm, PR_LOG_MIN, ("PR_Cleanup: shutting down NSPR"));
    PR_ASSERT(me->state & PT_THREAD_PRIMORD);
    if (me->state & PT_THREAD_PRIMORD)
    {
        PR_Lock(pt_book.ml);
        while (pt_book.user > pt_book.this_many)
            PR_WaitCondVar(pt_book.cv, PR_INTERVAL_NO_TIMEOUT);
        PR_Unlock(pt_book.ml);

        _PR_CleanupMW();
        _PR_CleanupDtoa();
        _PR_CleanupCallOnce();
        _PR_ShutdownLinker();
        _PR_LogCleanup();
        _PR_CleanupNet();
        /* Close all the fd's before calling _PR_CleanupIO */
        _PR_CleanupIO();

        /*
         * I am not sure if it's safe to delete the cv and lock here,
         * since there may still be "system" threads around. If this
         * call isn't immediately prior to exiting, then there's a
         * problem.
         */
        if (0 == pt_book.system)
        {
            PR_DestroyCondVar(pt_book.cv); pt_book.cv = NULL;
            PR_DestroyLock(pt_book.ml); pt_book.ml = NULL;
        }
        _pt_thread_death(me);
        PR_DestroyLock(_pr_sleeplock);
        _pr_sleeplock = NULL;
        _PR_CleanupLayerCache();
        _PR_CleanupEnv();
#ifdef _PR_ZONE_ALLOCATOR
        _PR_DestroyZones();
#endif
        _pr_initialized = PR_FALSE;
        return PR_SUCCESS;
    }
    return PR_FAILURE;
}  /* PR_Cleanup */

PR_IMPLEMENT(void) PR_ProcessExit(PRIntn status)
{
    _exit(status);
}

PR_IMPLEMENT(PRUint32) PR_GetThreadID(PRThread *thred)
{
#if defined(_PR_DCETHREADS)
    return (PRUint32)&thred->id;  /* this is really a sham! */
#else
    return (PRUint32)thred->id;  /* and I don't know what they will do with it */
#endif
}

/*
 * $$$
 * The following two thread-to-processor affinity functions are not
 * yet implemented for pthreads.  By the way, these functions should return
 * PRStatus rather than PRInt32 to indicate the success/failure status.
 * $$$
 */

PR_IMPLEMENT(PRInt32) PR_GetThreadAffinityMask(PRThread *thread, PRUint32 *mask)
{
    return 0;  /* not implemented */
}

PR_IMPLEMENT(PRInt32) PR_SetThreadAffinityMask(PRThread *thread, PRUint32 mask )
{
    return 0;  /* not implemented */
}

PR_IMPLEMENT(void)
PR_SetThreadDumpProc(PRThread* thread, PRThreadDumpProc dump, void *arg)
{
    thread->dump = dump;
    thread->dumpArg = arg;
}

/* 
 * Garbage collection support follows.
 */

#if defined(_PR_DCETHREADS)

/*
 * statics for Garbage Collection support.  We don't need to protect these
 * signal masks since the garbage collector itself is protected by a lock
 * and multiple threads will not be garbage collecting at the same time.
 */
static sigset_t javagc_vtalarm_sigmask;
static sigset_t javagc_intsoff_sigmask;

#else /* defined(_PR_DCETHREADS) */

/* a bogus signal mask for forcing a timed wait */
/* Not so bogus in AIX as we really do a sigwait */
static sigset_t sigwait_set;

static struct timespec onemillisec = {0, 1000000L};
#ifndef PT_NO_SIGTIMEDWAIT
static struct timespec hundredmillisec = {0, 100000000L};
#endif