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BUG#: 5314
TITLE: IPC Refactoring

DESCRIPTION: This patch cleans up the IPC related classes. It (1) reorganizes
related classes into their own headers, (2) makes the mutex class recursive to
eliminate recursive lock exclusion logic, (3) reimplements condition variables,
renames dozens of global functions.

//%2006////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation, The Open Group.
// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; Symantec Corporation; The Open Group.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Mike Brasher, Inova Europe (mike-brasher@austin.rr.com)
//
// Modified By: David Dillard, Symantec Corp. (david_dillard@symantec.com)
//
//%/////////////////////////////////////////////////////////////////////////////

#include "Network.h"

#if defined(PEGASUS_OS_SOLARIS)
# include <sys/types.h>
# include <unistd.h>
#endif

#include "SpinLock.h"

#if  !defined(PEGASUS_OS_VMS) &&  !defined(PEGASUS_OS_TYPE_WINDOWS)
# define PEGASUS_SPINLOCK_USE_PTHREADS
#endif

#ifdef PEGASUS_SPINLOCK_USE_PTHREADS
# include <pthread.h>
#else
# include "Mutex.h"
#endif

PEGASUS_NAMESPACE_BEGIN

SpinLock spinLockPool[PEGASUS_NUM_SHARED_SPIN_LOCKS];
int spinLockPoolInitialized;

#ifdef PEGASUS_SPINLOCK_USE_PTHREADS
pthread_mutex_t _spinLockInitMutex = PTHREAD_MUTEX_INITIALIZER;
#else
static Mutex _spinLockInitMutex;
#endif

void SpinLockCreatePool()
{
    // There's no need to check spinLockPoolInitialized before locking the
    // mutex, because the caller can check the flag before calling this
    // function.

#ifdef PEGASUS_SPINLOCK_USE_PTHREADS
    pthread_mutex_lock(&_spinLockInitMutex);
#else
    _spinLockInitMutex.lock();
#endif

    if (spinLockPoolInitialized == 0)
    {
        for (size_t i = 0; i < PEGASUS_NUM_SHARED_SPIN_LOCKS; i++)
            SpinLockCreate(spinLockPool[i]);

        spinLockPoolInitialized = 1;
    }

#ifdef PEGASUS_SPINLOCK_USE_PTHREADS
    pthread_mutex_unlock(&_spinLockInitMutex);
#else
    _spinLockInitMutex.unlock();
#endif
}

#if defined(PEGASUS_SPINLOCK_USE_PTHREADS)

// This function is called prior to forking.  We must obtain a lock
// on every mutex that the child will inherit.  These will remain locked
// until they are unlocked (by _unlockSpinLockPool()).  This prevents a
// child process from waiting indefinitely on a mutex that was locked by
// another thread in the parent process during the fork.

extern "C" void _lockSpinLockPool()
{
    // Initialize the spinlock pool if not already done.

    if (spinLockPoolInitialized == 0)
        SpinLockCreatePool();

    pthread_mutex_lock(&_spinLockInitMutex);

    for (size_t i = 0; i < PEGASUS_NUM_SHARED_SPIN_LOCKS; i++)
        SpinLockLock(spinLockPool[i]);
}

// This function is called after forking.  It unlocks the mutexes that
// were locked by _lockSpinLockPool() before the fork.

extern "C" void _unlockSpinLockPool()
{
    pthread_mutex_unlock(&_spinLockInitMutex);

    for (size_t i = 0; i < PEGASUS_NUM_SHARED_SPIN_LOCKS; i++)
        SpinLockUnlock(spinLockPool[i]);
}

class SpinLockInitializer
{
public:
    SpinLockInitializer()
    {
// ATTN: Temporary workaround for Bug 4559
#if defined(PEGASUS_OS_HPUX) || defined(PEGASUS_OS_SOLARIS)
        pthread_atfork(
            _lockSpinLockPool,
            _unlockSpinLockPool,
            _unlockSpinLockPool);
#endif
    }
};

static SpinLockInitializer spinLockInitializer;

#endif /* PEGASUS_SPINLOCK_USE_PTHREADS */

PEGASUS_NAMESPACE_END