pthread_rwlock_timedwrlock.c

很有名的一款用于组织DDoS的恶意机器人程序。仅供研究学习

/*
 * pthread_rwlock_timedwrlock.c
 *
 * Description:
 * This translation unit implements read/write lock primitives.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999,2003 Pthreads-win32 contributors
 * 
 *      Contact Email: [e-mail]
 * 
 *      The current list of contributors is contained
 *      in the file CONTRIBUTORS included with the source
 *      code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *      http://sources.redhat.com/pthreads-win32/contributors.html
 * 
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2 of the License, or (at your option) any later version.
 * 
 *      This library is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *      Lesser General Public License for more details.
 * 
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library in the file COPYING.LIB;
 *      if not, write to the Free Software Foundation, Inc.,
 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <errno.h>
#include <limits.h>

#include "pthread.h"
#include "implement.h"

int
pthread_rwlock_timedwrlock(pthread_rwlock_t * rwlock, const struct timespec * abstime)
{
    int result;
    pthread_rwlock_t rwl;

    if (rwlock == NULL || *rwlock == NULL)
      {
	return EINVAL;
      }

    /*
     * We do a quick check to see if we need to do more work
     * to initialise a static rwlock. We check
     * again inside the guarded section of ptw32_rwlock_check_need_init()
     * to avoid race conditions.
     */
    if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
      {
	result = ptw32_rwlock_check_need_init(rwlock);

	if (result != 0 && result != EBUSY)
	  {
	    return result;
	  }
      }

    rwl = *rwlock;

    if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
      {
	return EINVAL;
      }

    if ((result = pthread_mutex_timedlock(&(rwl->mtxExclusiveAccess), abstime)) != 0)
      {
	return result;
      }

    if ((result = pthread_mutex_timedlock(&(rwl->mtxSharedAccessCompleted), abstime)) != 0)
      {
	(void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
	return result;
      }

    if (rwl->nExclusiveAccessCount == 0) 
      {
	if (rwl->nCompletedSharedAccessCount > 0) 
	  {
	    rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
	    rwl->nCompletedSharedAccessCount = 0;
	  }

	if (rwl->nSharedAccessCount > 0) 
	  {
	    rwl->nCompletedSharedAccessCount = -rwl->nSharedAccessCount;

	    /*
	     * This routine may be a cancelation point
	     * according to POSIX 1003.1j section 18.1.2.
	     */
#ifdef _MSC_VER
#pragma inline_depth(0)
#endif
	    pthread_cleanup_push(ptw32_rwlock_cancelwrwait, (void*)rwl);

	    do
	      {
                result = pthread_cond_timedwait(&(rwl->cndSharedAccessCompleted),
                                                &(rwl->mtxSharedAccessCompleted),
                                                abstime);
	      }
	    while (result == 0 && rwl->nCompletedSharedAccessCount < 0);

	    pthread_cleanup_pop ((result != 0) ? 1 : 0);
#ifdef _MSC_VER
#pragma inline_depth()
#endif

	    if (result == 0)
	      {
		rwl->nSharedAccessCount = 0;
	      }
	  }
      }

    if (result == 0)
      {
	rwl->nExclusiveAccessCount++;
      }

    return result;
}