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/*
* pthread_mutex_lock.c
*
* Description:
* This translation unit implements mutual exclusion (mutex) primitives.
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2002 Pthreads-win32 contributors
*
* Contact Email: rpj@ise.canberra.edu.au
*
* 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 "pthread.h"
#include "implement.h"
static INLINE int
ptw32_semwait (sem_t * sem)
/*
* ------------------------------------------------------
* DESCRIPTION
* This function waits on a POSIX semaphore. If the
* semaphore value is greater than zero, it decreases
* its value by one. If the semaphore value is zero, then
* the calling thread (or process) is blocked until it can
* successfully decrease the value.
*
* Unlike sem_wait(), this routine is not a cancelation point.
*
* RESULTS
* 0 successfully decreased semaphore,
* -1 failed, error in errno.
* ERRNO
* EINVAL 'sem' is not a valid semaphore,
* ENOSYS semaphores are not supported,
* EINTR the function was interrupted by a signal,
* EDEADLK a deadlock condition was detected.
*
* ------------------------------------------------------
*/
{
int result = 0;
DWORD status;
if (sem == NULL)
{
result = EINVAL;
}
else
{
#ifdef NEED_SEM
status = WaitForSingleObject( (*sem)->event, INFINITE );
#else /* NEED_SEM */
status = WaitForSingleObject( (*sem)->sem, INFINITE );
#endif
if (status == WAIT_OBJECT_0)
{
#ifdef NEED_SEM
ptw32_decrease_semaphore(sem);
#endif /* NEED_SEM */
return 0;
}
else
{
result = EINVAL;
}
}
if (result != 0)
{
errno = result;
return -1;
}
return 0;
} /* ptw32_semwait */
int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
int result = 0;
pthread_mutex_t mx;
if (mutex == NULL || *mutex == NULL)
{
return EINVAL;
}
/*
* We do a quick check to see if we need to do more work
* to initialise a static mutex. We check
* again inside the guarded section of ptw32_mutex_check_need_init()
* to avoid race conditions.
*/
if (*mutex == PTHREAD_MUTEX_INITIALIZER)
{
if ((result = ptw32_mutex_check_need_init(mutex)) != 0)
{
return(result);
}
}
mx = *mutex;
if( 0 == InterlockedIncrement( &mx->lock_idx ) )
{
mx->recursive_count = 1;
mx->ownerThread = (mx->kind != PTHREAD_MUTEX_FAST_NP
? pthread_self()
: (pthread_t) PTW32_MUTEX_OWNER_ANONYMOUS);
}
else
{
if( mx->kind != PTHREAD_MUTEX_FAST_NP &&
pthread_equal( mx->ownerThread, pthread_self() ) )
{
(void) InterlockedDecrement( &mx->lock_idx );
if( mx->kind == PTHREAD_MUTEX_RECURSIVE_NP )
{
mx->recursive_count++;
}
else
{
result = EDEADLK;
}
}
else
{
if (ptw32_semwait( &mx->wait_sema ) == 0)
{
mx->recursive_count = 1;
mx->ownerThread = (mx->kind != PTHREAD_MUTEX_FAST_NP
? pthread_self()
: (pthread_t) PTW32_MUTEX_OWNER_ANONYMOUS);
}
else
{
result = errno;
}
}
}
return(result);
}
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