ptthread.c

Netscape NSPR库源码

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (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.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is the Netscape Portable Runtime (NSPR).
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are 
 * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
 * Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable 
 * instead of those above.  If you wish to allow use of your 
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the
 * GPL.
 */

/*
** File:            ptthread.c
** Descritpion:        Implemenation for threds using pthreds
** Exports:            ptthread.h
*/

#if defined(_PR_PTHREADS) || defined(_PR_DCETHREADS)

#include "prlog.h"
#include "primpl.h"
#include "prpdce.h"

#include <pthread.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>

/*
 * Record whether or not we have the privilege to set the scheduling
 * policy and priority of threads.  0 means that privilege is available.
 * EPERM means that privilege is not available.
 */

static PRIntn pt_schedpriv = 0;
extern PRLock *_pr_sleeplock;

static struct _PT_Bookeeping
{
    PRLock *ml;                 /* a lock to protect ourselves */
    PRCondVar *cv;              /* used to signal global things */
    PRInt32 system, user;       /* a count of the two different types */
    PRUintn this_many;          /* number of threads allowed for exit */
    pthread_key_t key;          /* private private data key */
    PRThread *first, *last;     /* list of threads we know about */
#if defined(_PR_DCETHREADS) || defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
    PRInt32 minPrio, maxPrio;   /* range of scheduling priorities */
#endif
} pt_book = {0};

static void _pt_thread_death(void *arg);
static void init_pthread_gc_support(void);

#if defined(_PR_DCETHREADS) || defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
static PRIntn pt_PriorityMap(PRThreadPriority pri)
{
#ifdef NTO
    /* This priority algorithm causes lots of problems on Neutrino
     * for now I have just hard coded everything to run at priority 10
     * until I can come up with a new algorithm.
     *     [e-mail]
     */
    return 10;
#else
    return pt_book.minPrio +
	    pri * (pt_book.maxPrio - pt_book.minPrio) / PR_PRIORITY_LAST;
#endif
}
#endif

#if defined(GC_LEAK_DETECTOR) && (__GLIBC__ >= 2) && defined(__i386__) 

#include <setjmp.h>

typedef struct stack_frame stack_frame;

struct stack_frame {
    stack_frame* next;
    void* pc;
};

static stack_frame* GetStackFrame()
{
    jmp_buf jb;
    stack_frame* currentFrame;
    setjmp(jb);
    currentFrame = (stack_frame*)(jb[0].__jmpbuf[JB_BP]);
    currentFrame = currentFrame->next;
    return currentFrame;
}

static void* GetStackTop()
{
    stack_frame* frame;
    frame = GetStackFrame();
    while (frame != NULL)
    {
        ptrdiff_t pc = (ptrdiff_t)frame->pc;
        if ((pc < 0x08000000) || (pc > 0x7fffffff) || (frame->next < frame))
            return frame;
        frame = frame->next;
    }
    return NULL;
}
#endif /* GC_LEAK_DETECTOR && (__GLIBC__ >= 2) && __i386__ */

/*
** Initialize a stack for a native pthread thread
*/
static void _PR_InitializeStack(PRThreadStack *ts)
{
    if( ts && (ts->stackTop == 0) ) {
        ts->allocBase = (char *) &ts;
        ts->allocSize = ts->stackSize;

        /*
        ** Setup stackTop and stackBottom values.
        */
#ifdef HAVE_STACK_GROWING_UP
        ts->stackBottom = ts->allocBase + ts->stackSize;
        ts->stackTop = ts->allocBase;
#else
#ifdef GC_LEAK_DETECTOR
        ts->stackTop    = GetStackTop();
        ts->stackBottom = ts->stackTop - ts->stackSize;
#else
        ts->stackTop    = ts->allocBase;
        ts->stackBottom = ts->allocBase - ts->stackSize;
#endif
#endif
    }
}

static void *_pt_root(void *arg)
{
    PRIntn rv;
    PRThread *thred = (PRThread*)arg;
    PRBool detached = (thred->state & PT_THREAD_DETACHED) ? PR_TRUE : PR_FALSE;

    /*
     * Both the parent thread and this new thread set thred->id.
     * The new thread must ensure that thred->id is set before
     * it executes its startFunc.  The parent thread must ensure
     * that thred->id is set before PR_CreateThread() returns.
     * Both threads set thred->id without holding a lock.  Since
     * they are writing the same value, this unprotected double
     * write should be safe.
     */
    thred->id = pthread_self();

    /*
    ** DCE Threads can't detach during creation, so do it late.
    ** I would like to do it only here, but that doesn't seem
    ** to work.
    */
#if defined(_PR_DCETHREADS)
    if (detached)
    {
        /* pthread_detach() modifies its argument, so we must pass a copy */
        pthread_t self = thred->id;
        rv = pthread_detach(&self);
        PR_ASSERT(0 == rv);
    }
#endif /* defined(_PR_DCETHREADS) */

    /* Set up the thread stack information */
    _PR_InitializeStack(thred->stack);

    /*
     * Set within the current thread the pointer to our object.
     * This object will be deleted when the thread termintates,
     * whether in a join or detached (see _PR_InitThreads()).
     */
    rv = pthread_setspecific(pt_book.key, thred);
    PR_ASSERT(0 == rv);

    /* make the thread visible to the rest of the runtime */
    PR_Lock(pt_book.ml);

    /* If this is a GCABLE thread, set its state appropriately */
    if (thred->suspend & PT_THREAD_SETGCABLE)
	    thred->state |= PT_THREAD_GCABLE;
    thred->suspend = 0;

    thred->prev = pt_book.last;
    pt_book.last->next = thred;
    thred->next = NULL;
    pt_book.last = thred;
    PR_Unlock(pt_book.ml);

    thred->startFunc(thred->arg);  /* make visible to the client */

    /* unhook the thread from the runtime */
    PR_Lock(pt_book.ml);
    /*
     * At this moment, PR_CreateThread() may not have set thred->id yet.
     * It is safe for a detached thread to free thred only after
     * PR_CreateThread() has set thred->id.
     */
    if (detached)
    {
        while (!thred->okToDelete)
            PR_WaitCondVar(pt_book.cv, PR_INTERVAL_NO_TIMEOUT);
    }

    if (thred->state & PT_THREAD_SYSTEM)
        pt_book.system -= 1;
    else if (--pt_book.user == pt_book.this_many)
        PR_NotifyAllCondVar(pt_book.cv);
    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);

    /*
    * Here we set the pthread's backpointer to the PRThread to NULL.
    * Otherwise the desctructor would get called eagerly as the thread
    * returns to the pthread runtime. The joining thread would them be
    * the proud possessor of a dangling reference. However, this is the
    * last chance to delete the object if the thread is detached, so
    * just let the destuctor do the work.
    */
    if (PR_FALSE == detached)
    {
        rv = pthread_setspecific(pt_book.key, NULL);
        PR_ASSERT(0 == rv);
    }

    return NULL;
}  /* _pt_root */

static PRThread* pt_AttachThread(void)
{
    PRThread *thred = NULL;

    /*
     * NSPR must have been initialized when PR_AttachThread is called.
     * We cannot have PR_AttachThread call implicit initialization
     * because if multiple threads call PR_AttachThread simultaneously,
     * NSPR may be initialized more than once.
     * We can't call any function that calls PR_GetCurrentThread()
     * either (e.g., PR_SetError()) as that will result in infinite
     * recursion.
     */
    if (!_pr_initialized) return NULL;

    /* PR_NEWZAP must not call PR_GetCurrentThread() */
    thred = PR_NEWZAP(PRThread);
    if (NULL != thred)
    {
        int rv;

        thred->priority = PR_PRIORITY_NORMAL;
        thred->id = pthread_self();
        rv = pthread_setspecific(pt_book.key, thred);
        PR_ASSERT(0 == rv);

        thred->state = PT_THREAD_GLOBAL | PT_THREAD_FOREIGN;
        PR_Lock(pt_book.ml);

        /* then put it into the list */
        thred->prev = pt_book.last;
	    pt_book.last->next = thred;
        thred->next = NULL;
        pt_book.last = thred;
        PR_Unlock(pt_book.ml);

    }
    return thred;  /* may be NULL */
}  /* pt_AttachThread */

static PRThread* _PR_CreateThread(
    PRThreadType type, void (*start)(void *arg),
    void *arg, PRThreadPriority priority, PRThreadScope scope,
    PRThreadState state, PRUint32 stackSize, PRBool isGCAble)
{
    int rv;
    PRThread *thred;
    pthread_attr_t tattr;

    if (!_pr_initialized) _PR_ImplicitInitialization();

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

    rv = _PT_PTHREAD_ATTR_INIT(&tattr);
    PR_ASSERT(0 == rv);

    if (EPERM != pt_schedpriv)
    {
#if !defined(_PR_DCETHREADS) && defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        struct sched_param schedule;
#endif

#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        rv = pthread_attr_setinheritsched(&tattr, PTHREAD_EXPLICIT_SCHED);
        PR_ASSERT(0 == rv);
#endif

        /* Use the default scheduling policy */

#if defined(_PR_DCETHREADS)
        rv = pthread_attr_setprio(&tattr, pt_PriorityMap(priority));
        PR_ASSERT(0 == rv);
#elif defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        rv = pthread_attr_getschedparam(&tattr, &schedule);
        PR_ASSERT(0 == rv);
        schedule.sched_priority = pt_PriorityMap(priority);
        rv = pthread_attr_setschedparam(&tattr, &schedule);
        PR_ASSERT(0 == rv);
#ifdef NTO
        rv = pthread_attr_setschedpolicy(&tattr, SCHED_RR); /* Round Robin */
        PR_ASSERT(0 == rv);
#endif
#endif /* !defined(_PR_DCETHREADS) */
    }

    /*
     * DCE threads can't set detach state before creating the thread.
     * AIX can't set detach late. Why can't we all just get along?
     */
#if !defined(_PR_DCETHREADS)
    rv = pthread_attr_setdetachstate(&tattr,
        ((PR_JOINABLE_THREAD == state) ?
            PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
    PR_ASSERT(0 == rv);
#endif /* !defined(_PR_DCETHREADS) */

    if (0 == stackSize) stackSize = (64 * 1024);  /* default == 64K */
#ifdef _MD_MINIMUM_STACK_SIZE
    if (stackSize < _MD_MINIMUM_STACK_SIZE) stackSize = _MD_MINIMUM_STACK_SIZE;
#endif
    /*
     * Linux doesn't have pthread_attr_setstacksize.
     */
#ifndef LINUX
    rv = pthread_attr_setstacksize(&tattr, stackSize);
    PR_ASSERT(0 == rv);
#endif

    thred = PR_NEWZAP(PRThread);
    if (NULL == thred)
    {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, errno);
        goto done;
    }
    else
    {
        pthread_t id;

        thred->arg = arg;
        thred->startFunc = start;
        thred->priority = priority;
        if (PR_UNJOINABLE_THREAD == state)
            thred->state |= PT_THREAD_DETACHED;

        if (PR_LOCAL_THREAD == scope)
        	scope = PR_GLOBAL_THREAD;
			
        if (PR_GLOBAL_BOUND_THREAD == scope) {
#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
    		rv = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM);
			if (rv) {
				/*
				 * system scope not supported
				 */
        		scope = PR_GLOBAL_THREAD;
				/*
				 * reset scope
				 */
    			rv = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_PROCESS);
    			PR_ASSERT(0 == rv);
			}
#endif
		}
        if (PR_GLOBAL_THREAD == scope)
            thred->state |= PT_THREAD_GLOBAL;
        else if (PR_GLOBAL_BOUND_THREAD == scope)
            thred->state |= (PT_THREAD_GLOBAL | PT_THREAD_BOUND);
		else	/* force it global */
            thred->state |= PT_THREAD_GLOBAL;
        if (PR_SYSTEM_THREAD == type)
            thred->state |= PT_THREAD_SYSTEM;

        thred->suspend =(isGCAble) ? PT_THREAD_SETGCABLE : 0;

        thred->stack = PR_NEWZAP(PRThreadStack);
        if (thred->stack == NULL) {
            PRIntn oserr = errno;
            PR_Free(thred);  /* all that work ... poof! */
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, oserr);
            thred = NULL;  /* and for what? */
            goto done;
        }
        thred->stack->stackSize = stackSize;
        thred->stack->thr = thred;

#ifdef PT_NO_SIGTIMEDWAIT
        pthread_mutex_init(&thred->suspendResumeMutex,NULL);
        pthread_cond_init(&thred->suspendResumeCV,NULL);
#endif

        /* make the thread counted to the rest of the runtime */
        PR_Lock(pt_book.ml);
        if (PR_SYSTEM_THREAD == type)
            pt_book.system += 1;
        else pt_book.user += 1;
        PR_Unlock(pt_book.ml);

        /*
         * We pass a pointer to a local copy (instead of thred->id)
         * to pthread_create() because who knows what wacky things
         * pthread_create() may be doing to its argument.
         */
        rv = _PT_PTHREAD_CREATE(&id, tattr, _pt_root, thred);

#if !defined(_PR_DCETHREADS)
        if (EPERM == rv)
        {
#if defined(IRIX)
        	if (PR_GLOBAL_BOUND_THREAD == scope) {
				/*
				 * SCOPE_SYSTEM requires appropriate privilege
				 * reset to process scope and try again
				 */
    			rv = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_PROCESS);
    			PR_ASSERT(0 == rv);
            	thred->state &= ~PT_THREAD_BOUND;
			}
#else
            /* Remember that we don't have thread scheduling privilege. */
            pt_schedpriv = EPERM;
            PR_LOG(_pr_thread_lm, PR_LOG_MIN,
                ("_PR_CreateThread: no thread scheduling privilege"));
            /* Try creating the thread again without setting priority. */
#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
            rv = pthread_attr_setinheritsched(&tattr, PTHREAD_INHERIT_SCHED);
            PR_ASSERT(0 == rv);
#endif
#endif	/* IRIX */
            rv = _PT_PTHREAD_CREATE(&id, tattr, _pt_root, thred);
        }
#endif

        if (0 != rv)
        {
#if defined(_PR_DCETHREADS)
            PRIntn oserr = errno;
#else
            PRIntn oserr = rv;
#endif
            PR_Lock(pt_book.ml);
            if (thred->state & PT_THREAD_SYSTEM)
                pt_book.system -= 1;
            else if (--pt_book.user == pt_book.this_many)
                PR_NotifyAllCondVar(pt_book.cv);
            PR_Unlock(pt_book.ml);

            PR_Free(thred->stack);
            PR_Free(thred);  /* all that work ... poof! */
            PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, oserr);
            thred = NULL;  /* and for what? */
            goto done;
        }

        /*
         * Both the parent thread and this new thread set thred->id.
         * The parent thread must ensure that thred->id is set before
         * PR_CreateThread() returns.  (See comments in _pt_root().)
         */
        thred->id = id;

        /*
         * If the new thread is detached, tell it that PR_CreateThread()
         * has set thred->id so it's ok to delete thred.
         */
        if (PR_UNJOINABLE_THREAD == state)
        {
            PR_Lock(pt_book.ml);
            thred->okToDelete = PR_TRUE;
            PR_NotifyAllCondVar(pt_book.cv);
            PR_Unlock(pt_book.ml);
        }