The Tor Browser: nsprpub/pr/src/bthreads/btthread.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/bthreads/btthread.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/bthreads/btthread.c

Wed, 31 Dec 2014 06:55:46 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:46 +0100
changeset 1: ca08bd8f51b2
permissions: -rw-r--r--

Added tag TORBROWSER_REPLICA for changeset 6474c204b198

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <kernel/OS.h>
 #include <support/TLS.h>
 #include "prlog.h"
 #include "primpl.h"
 #include "prcvar.h"
 #include "prpdce.h"
 #include <stdlib.h>
 #include <string.h>
 #include <signal.h>
 /* values for PRThread.state */
 #define BT_THREAD_PRIMORD   0x01    /* this is the primordial thread */
 #define BT_THREAD_SYSTEM    0x02    /* this is a system thread */
 #define BT_THREAD_JOINABLE  0x04	/* this is a joinable thread */
 struct _BT_Bookeeping
 {
     PRLock *ml;                 /* a lock to protect ourselves */
 	sem_id cleanUpSem;		/* the primoridal thread will block on this
 							   sem while waiting for the user threads */
     PRInt32 threadCount;	/* user thred count */
 } bt_book = { NULL, B_ERROR, 0 };
 #define BT_TPD_LIMIT 128	/* number of TPD slots we'll provide (arbitrary) */
 /* these will be used to map an index returned by PR_NewThreadPrivateIndex()
    to the corresponding beos native TLS slot number, and to the destructor
    for that slot - note that, because it is allocated globally, this data
    will be automatically zeroed for us when the program begins */
 static int32 tpd_beosTLSSlots[BT_TPD_LIMIT];
 static PRThreadPrivateDTOR tpd_dtors[BT_TPD_LIMIT];
 static vint32 tpd_slotsUsed=0;	/* number of currently-allocated TPD slots */
 static int32 tls_prThreadSlot;	/* TLS slot in which PRThread will be stored */
 /* this mutex will be used to synchronize access to every
    PRThread.md.joinSem and PRThread.md.is_joining (we could
    actually allocate one per thread, but that seems a bit excessive,
    especially considering that there will probably be little
    contention, PR_JoinThread() is allowed to block anyway, and the code
    protected by the mutex is short/fast) */
 static PRLock *joinSemLock;
 static PRUint32 _bt_MapNSPRToNativePriority( PRThreadPriority priority );
 static PRThreadPriority _bt_MapNativeToNSPRPriority( PRUint32 priority );
 static void _bt_CleanupThread(void *arg);
 static PRThread *_bt_AttachThread();
 void
 _PR_InitThreads (PRThreadType type, PRThreadPriority priority,
                  PRUintn maxPTDs)
 {
     PRThread *primordialThread;
     PRUint32  beThreadPriority;
 	/* allocate joinSem mutex */
 	joinSemLock = PR_NewLock();
 	if (joinSemLock == NULL)
 	{
 		PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
 		return;
     }
     /*
     ** Create and initialize NSPR structure for our primordial thread.
     */
     primordialThread = PR_NEWZAP(PRThread);
     if( NULL == primordialThread )
     {
         PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
         return;
     }
 	primordialThread->md.joinSem = B_ERROR;
     /*
     ** Set the priority to the desired level.
     */
     beThreadPriority = _bt_MapNSPRToNativePriority( priority );
     set_thread_priority( find_thread( NULL ), beThreadPriority );
     primordialThread->priority = priority;
 	/* set the thread's state - note that the thread is not joinable */
     primordialThread->state |= BT_THREAD_PRIMORD;
 	if (type == PR_SYSTEM_THREAD)
 		primordialThread->state |= BT_THREAD_SYSTEM;
     /*
     ** Allocate a TLS slot for the PRThread structure (just using
     ** native TLS, as opposed to NSPR TPD, will make PR_GetCurrentThread()
     ** somewhat faster, and will leave one more TPD slot for our client)
     */
 	tls_prThreadSlot = tls_allocate();
     /*
     ** Stuff our new PRThread structure into our thread specific
     ** slot.
     */
 	tls_set(tls_prThreadSlot, primordialThread);
 	/* allocate lock for bt_book */
     bt_book.ml = PR_NewLock();
     if( NULL == bt_book.ml )
     {
     	PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
 	return;
     }
 }
 PRUint32
 _bt_MapNSPRToNativePriority( PRThreadPriority priority )
     {
     switch( priority )
     {
     	case PR_PRIORITY_LOW:	 return( B_LOW_PRIORITY );
 	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
 	case PR_PRIORITY_HIGH:	 return( B_DISPLAY_PRIORITY );
 	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
 	default:		 return( B_NORMAL_PRIORITY );
     }
 }
 PRThreadPriority
 _bt_MapNativeToNSPRPriority(PRUint32 priority)
     {
 	if (priority < B_NORMAL_PRIORITY)
 		return PR_PRIORITY_LOW;
 	if (priority < B_DISPLAY_PRIORITY)
 		return PR_PRIORITY_NORMAL;
 	if (priority < B_URGENT_DISPLAY_PRIORITY)
 		return PR_PRIORITY_HIGH;
 	return PR_PRIORITY_URGENT;
 }
 PRUint32
 _bt_mapNativeToNSPRPriority( int32 priority )
 {
     switch( priority )
     {
     	case PR_PRIORITY_LOW:	 return( B_LOW_PRIORITY );
 	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
 	case PR_PRIORITY_HIGH:	 return( B_DISPLAY_PRIORITY );
 	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
 	default:		 return( B_NORMAL_PRIORITY );
     }
 }
 /* This method is called by all NSPR threads as they exit */
 void _bt_CleanupThread(void *arg)
 {
 	PRThread *me = PR_GetCurrentThread();
 	int32 i;
 	/* first, clean up all thread-private data */
 	for (i = 0; i < tpd_slotsUsed; i++)
 	{
 		void *oldValue = tls_get(tpd_beosTLSSlots[i]);
 		if ( oldValue != NULL && tpd_dtors[i] != NULL )
 			(*tpd_dtors[i])(oldValue);
 	}
 	/* if this thread is joinable, wait for someone to join it */
 	if (me->state & BT_THREAD_JOINABLE)
 	{
 		/* protect access to our joinSem */
 		PR_Lock(joinSemLock);
 		if (me->md.is_joining)
 		{
 			/* someone is already waiting to join us (they've
 			   allocated a joinSem for us) - let them know we're
 			   ready */
 			delete_sem(me->md.joinSem);
 			PR_Unlock(joinSemLock);
 		}
 		else
     {
 			/* noone is currently waiting for our demise - it
 			   is our responsibility to allocate the joinSem
 			   and block on it */
 			me->md.joinSem = create_sem(0, "join sem");
 			/* we're done accessing our joinSem */
 			PR_Unlock(joinSemLock);
 			/* wait for someone to join us */
 			while (acquire_sem(me->md.joinSem) == B_INTERRUPTED);
 	    }
 	}
 	/* if this is a user thread, we must update our books */
 	if ((me->state & BT_THREAD_SYSTEM) == 0)
 	{
 		/* synchronize access to bt_book */
     PR_Lock( bt_book.ml );
 		/* decrement the number of currently-alive user threads */
 	bt_book.threadCount--;
 		if (bt_book.threadCount == 0 && bt_book.cleanUpSem != B_ERROR) {
 			/* we are the last user thread, and the primordial thread is
 			   blocked in PR_Cleanup() waiting for us to finish - notify
 			   it */
 			delete_sem(bt_book.cleanUpSem);
 	}
     PR_Unlock( bt_book.ml );
 	}
 	/* finally, delete this thread's PRThread */
 	PR_DELETE(me);
 }
 /**
  * This is a wrapper that all threads invoke that allows us to set some
  * things up prior to a thread's invocation and clean up after a thread has
  * exited.
  */
 static void*
 _bt_root (void* arg)
 	{
     PRThread *thred = (PRThread*)arg;
     PRIntn rv;
     void *privData;
     status_t result;
     int i;
 	/* save our PRThread object into our TLS */
 	tls_set(tls_prThreadSlot, thred);
     thred->startFunc(thred->arg);  /* run the dang thing */
 	/* clean up */
 	_bt_CleanupThread(NULL);
 	return 0;
 }
 PR_IMPLEMENT(PRThread*)
     PR_CreateThread (PRThreadType type, void (*start)(void* arg), void* arg,
                      PRThreadPriority priority, PRThreadScope scope,
                      PRThreadState state, PRUint32 stackSize)
 {
     PRUint32 bePriority;
     PRThread* thred;
     if (!_pr_initialized) _PR_ImplicitInitialization();
 	thred = PR_NEWZAP(PRThread);
  	if (thred == NULL)
 	{
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         return NULL;
     }
     thred->md.joinSem = B_ERROR;
         thred->arg = arg;
         thred->startFunc = start;
         thred->priority = priority;
 	if( state == PR_JOINABLE_THREAD )
 	{
 	    thred->state |= BT_THREAD_JOINABLE;
 	}
         /* keep some books */
 	PR_Lock( bt_book.ml );
 	if (type == PR_USER_THREAD)
 	{
 	    bt_book.threadCount++;
         }
 	PR_Unlock( bt_book.ml );
 	bePriority = _bt_MapNSPRToNativePriority( priority );
         thred->md.tid = spawn_thread((thread_func)_bt_root, "moz-thread",
                                      bePriority, thred);
         if (thred->md.tid < B_OK) {
             PR_SetError(PR_UNKNOWN_ERROR, thred->md.tid);
             PR_DELETE(thred);
 			return NULL;
         }
         if (resume_thread(thred->md.tid) < B_OK) {
             PR_SetError(PR_UNKNOWN_ERROR, 0);
             PR_DELETE(thred);
 			return NULL;
         }
     return thred;
     }
 PR_IMPLEMENT(PRThread*)
 	PR_AttachThread(PRThreadType type, PRThreadPriority priority,
 					PRThreadStack *stack)
 {
 	/* PR_GetCurrentThread() will attach a thread if necessary */
 	return PR_GetCurrentThread();
 }
 PR_IMPLEMENT(void)
 	PR_DetachThread()
 {
 	/* we don't support detaching */
 }
 PR_IMPLEMENT(PRStatus)
     PR_JoinThread (PRThread* thred)
 {
     status_t eval, status;
     PR_ASSERT(thred != NULL);
 	if ((thred->state & BT_THREAD_JOINABLE) == 0)
     {
 	PR_SetError( PR_INVALID_ARGUMENT_ERROR, 0 );
 	return( PR_FAILURE );
     }
 	/* synchronize access to the thread's joinSem */
 	PR_Lock(joinSemLock);
 	if (thred->md.is_joining)
 	{
 		/* another thread is already waiting to join the specified
 		   thread - we must fail */
 		PR_Unlock(joinSemLock);
 		return PR_FAILURE;
 	}
 	/* let others know we are waiting to join */
 	thred->md.is_joining = PR_TRUE;
 	if (thred->md.joinSem == B_ERROR)
 	{
 		/* the thread hasn't finished yet - it is our responsibility to
 		   allocate a joinSem and wait on it */
 		thred->md.joinSem = create_sem(0, "join sem");
 		/* we're done changing the joinSem now */
 		PR_Unlock(joinSemLock);
 		/* wait for the thread to finish */
 		while (acquire_sem(thred->md.joinSem) == B_INTERRUPTED);
 	}
 	else
 	{
 		/* the thread has already finished, and has allocated the
 		   joinSem itself - let it know it can finally die */
 		delete_sem(thred->md.joinSem);
 		PR_Unlock(joinSemLock);
     }
 	/* make sure the thread is dead */
     wait_for_thread(thred->md.tid, &eval);
     return PR_SUCCESS;
 }
 PR_IMPLEMENT(PRThread*)
     PR_GetCurrentThread ()
 {
     PRThread* thred;
     if (!_pr_initialized) _PR_ImplicitInitialization();
     thred = (PRThread *)tls_get( tls_prThreadSlot);
 	if (thred == NULL)
 	{
 		/* this thread doesn't have a PRThread structure (it must be
 		   a native thread not created by the NSPR) - assimilate it */
 		thred = _bt_AttachThread();
 	}
     PR_ASSERT(NULL != thred);
     return thred;
 }
 PR_IMPLEMENT(PRThreadScope)
     PR_GetThreadScope (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return PR_GLOBAL_THREAD;
 }
 PR_IMPLEMENT(PRThreadType)
     PR_GetThreadType (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return (thred->state & BT_THREAD_SYSTEM) ?
         PR_SYSTEM_THREAD : PR_USER_THREAD;
 }
 PR_IMPLEMENT(PRThreadState)
     PR_GetThreadState (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return (thred->state & BT_THREAD_JOINABLE)?
     					PR_JOINABLE_THREAD: PR_UNJOINABLE_THREAD;
 }
 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)
 {
     PRUint32 bePriority;
     PR_ASSERT( thred != NULL );
     thred->priority = newPri;
     bePriority = _bt_MapNSPRToNativePriority( newPri );
     set_thread_priority( thred->md.tid, bePriority );
 }
 PR_IMPLEMENT(PRStatus)
     PR_NewThreadPrivateIndex (PRUintn* newIndex,
                               PRThreadPrivateDTOR destructor)
 {
 	int32    index;
     if (!_pr_initialized) _PR_ImplicitInitialization();
 	/* reserve the next available tpd slot */
 	index = atomic_add( &tpd_slotsUsed, 1 );
 	if (index >= BT_TPD_LIMIT)
 	{
 		/* no slots left - decrement value, then fail */
 		atomic_add( &tpd_slotsUsed, -1 );
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 	    return( PR_FAILURE );
 	}
 	/* allocate a beos-native TLS slot for this index (the new slot
 	   automatically contains NULL) */
 	tpd_beosTLSSlots[index] = tls_allocate();
 	/* remember the destructor */
 	tpd_dtors[index] = destructor;
     *newIndex = (PRUintn)index;
     return( PR_SUCCESS );
 }
 PR_IMPLEMENT(PRStatus)
     PR_SetThreadPrivate (PRUintn index, void* priv)
 {
 	void *oldValue;
     /*
     ** Sanity checking
     */
     if(index < 0 || index >= tpd_slotsUsed || index >= BT_TPD_LIMIT)
     {
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 	return( PR_FAILURE );
     }
 	/* if the old value isn't NULL, and the dtor for this slot isn't
 	   NULL, we must destroy the data */
 	oldValue = tls_get(tpd_beosTLSSlots[index]);
 	if (oldValue != NULL && tpd_dtors[index] != NULL)
 		(*tpd_dtors[index])(oldValue);
 	/* save new value */
 	tls_set(tpd_beosTLSSlots[index], priv);
 	    return( PR_SUCCESS );
 	}
 PR_IMPLEMENT(void*)
     PR_GetThreadPrivate (PRUintn index)
 {
 	/* make sure the index is valid */
 	if (index < 0 || index >= tpd_slotsUsed || index >= BT_TPD_LIMIT)
     {
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 		return NULL;
     }
 	/* return the value */
 	return tls_get( tpd_beosTLSSlots[index] );
 	}
 PR_IMPLEMENT(PRStatus)
     PR_Interrupt (PRThread* thred)
 {
     PRIntn rv;
     PR_ASSERT(thred != NULL);
     /*
     ** there seems to be a bug in beos R5 in which calling
     ** resume_thread() on a blocked thread returns B_OK instead
     ** of B_BAD_THREAD_STATE (beos bug #20000422-19095).  as such,
     ** to interrupt a thread, we will simply suspend then resume it
     ** (no longer call resume_thread(), check for B_BAD_THREAD_STATE,
     ** the suspend/resume to wake up a blocked thread).  this wakes
     ** up blocked threads properly, and doesn't hurt unblocked threads
     ** (they simply get stopped then re-started immediately)
     */
     rv = suspend_thread( thred->md.tid );
     if( rv != B_NO_ERROR )
     {
         /* this doesn't appear to be a valid thread_id */
         PR_SetError( PR_UNKNOWN_ERROR, rv );
         return PR_FAILURE;
     }
     rv = resume_thread( thred->md.tid );
     if( rv != B_NO_ERROR )
     {
         PR_SetError( PR_UNKNOWN_ERROR, rv );
         return PR_FAILURE;
     }
     return PR_SUCCESS;
 }
 PR_IMPLEMENT(void)
     PR_ClearInterrupt ()
 {
 }
 PR_IMPLEMENT(PRStatus)
     PR_Yield ()
 {
     /* we just sleep for long enough to cause a reschedule (100
        microseconds) */
     snooze(100);
 }
 #define BT_MILLION 1000000UL
 PR_IMPLEMENT(PRStatus)
     PR_Sleep (PRIntervalTime ticks)
 {
     bigtime_t tps;
     status_t status;
     if (!_pr_initialized) _PR_ImplicitInitialization();
     tps = PR_IntervalToMicroseconds( ticks );
     status = snooze(tps);
     if (status == B_NO_ERROR) return PR_SUCCESS;
     PR_SetError(PR_NOT_IMPLEMENTED_ERROR, status);
     return PR_FAILURE;
 }
 PR_IMPLEMENT(PRStatus)
     PR_Cleanup ()
 {
     PRThread *me = PR_GetCurrentThread();
     PR_ASSERT(me->state & BT_THREAD_PRIMORD);
     if ((me->state & BT_THREAD_PRIMORD) == 0) {
         return PR_FAILURE;
     }
     PR_Lock( bt_book.ml );
 	if (bt_book.threadCount != 0)
     {
 		/* we'll have to wait for some threads to finish - create a
 		   sem to block on */
 		bt_book.cleanUpSem = create_sem(0, "cleanup sem");
     }
     PR_Unlock( bt_book.ml );
 	/* note that, if all the user threads were already dead, we
 	   wouldn't have created a sem above, so this acquire_sem()
 	   will fail immediately */
 	while (acquire_sem(bt_book.cleanUpSem) == B_INTERRUPTED);
     return PR_SUCCESS;
 }
 PR_IMPLEMENT(void)
     PR_ProcessExit (PRIntn status)
 {
     exit(status);
 }
 PRThread *_bt_AttachThread()
 {
 	PRThread *thread;
 	thread_info tInfo;
 	/* make sure this thread doesn't already have a PRThread structure */
 	PR_ASSERT(tls_get(tls_prThreadSlot) == NULL);
 	/* allocate a PRThread structure for this thread */
 	thread = PR_NEWZAP(PRThread);
 	if (thread == NULL)
 	{
 		PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
 		return NULL;
 	}
 	/* get the native thread's current state */
 	get_thread_info(find_thread(NULL), &tInfo);
 	/* initialize new PRThread */
 	thread->md.tid = tInfo.thread;
 	thread->md.joinSem = B_ERROR;
 	thread->priority = _bt_MapNativeToNSPRPriority(tInfo.priority);
 	/* attached threads are always non-joinable user threads */
 	thread->state = 0;
 	/* increment user thread count */
 	PR_Lock(bt_book.ml);
 	bt_book.threadCount++;
 	PR_Unlock(bt_book.ml);
 	/* store this thread's PRThread */
 	tls_set(tls_prThreadSlot, thread);
 	/* the thread must call _bt_CleanupThread() before it dies, in order
 	   to clean up its PRThread, synchronize with the primordial thread,
 	   etc. */
 	on_exit_thread(_bt_CleanupThread, NULL);
 	return thread;
 }

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nsprpub/pr/src/bthreads/btthread.c@ca08bd8f51b2 (annotated)

nsprpub/pr/src/bthreads/btthread.c