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/* Lock a mutex with a timeout. Generic version.
Copyright (C) 2000, 2002, 2005, 2008 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see 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 <assert.h>
#include <pt-internal.h>
#define LOSE do { * (int *) 0 = 0; } while (1)
/* Try to lock MUTEX, block until *ABSTIME if it is already held. As
a GNU extension, if TIMESPEC is NULL then wait forever. */
int
__pthread_mutex_timedlock_internal (struct __pthread_mutex *mutex,
const struct timespec *abstime)
{
struct __pthread *self;
__pthread_spin_lock (&mutex->__lock);
if (__pthread_spin_trylock (&mutex->__held) == 0)
/* Successfully acquired the lock. */
{
#ifndef NDEBUG
self = _pthread_self ();
if (self)
/* The main thread may take a lock before the library is fully
initialized, in particular, before the main thread has a
TCB. */
{
assert (! mutex->owner);
mutex->owner = _pthread_self ();
}
#endif
if (mutex->attr)
switch (mutex->attr->mutex_type)
{
case PTHREAD_MUTEX_NORMAL:
break;
case PTHREAD_MUTEX_RECURSIVE:
mutex->locks = 1;
case PTHREAD_MUTEX_ERRORCHECK:
mutex->owner = _pthread_self ();
break;
default:
LOSE;
}
__pthread_spin_unlock (&mutex->__lock);
return 0;
}
/* The lock is busy. */
self = _pthread_self ();
assert (self);
if (mutex->attr)
{
switch (mutex->attr->mutex_type)
{
case PTHREAD_MUTEX_NORMAL:
assert (mutex->owner != self);
break;
case PTHREAD_MUTEX_ERRORCHECK:
if (mutex->owner == self)
{
__pthread_spin_unlock (&mutex->__lock);
return EDEADLK;
}
break;
case PTHREAD_MUTEX_RECURSIVE:
if (mutex->owner == self)
{
mutex->locks ++;
__pthread_spin_unlock (&mutex->__lock);
return 0;
}
break;
default:
LOSE;
}
}
else
assert (mutex->owner != self);
assert (mutex->owner);
if (abstime && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
return EINVAL;
/* Add ourselves to the queue. */
__pthread_enqueue (&mutex->__queue, self);
__pthread_spin_unlock (&mutex->__lock);
/* Block the thread. */
if (abstime)
{
error_t err;
err = __pthread_timedblock (self, abstime);
if (err)
/* We timed out. We may need to disconnect ourself from the
waiter queue.
FIXME: What do we do if we get a wakeup message before we
disconnect ourself? It may remain until the next time we
block. */
{
assert (err == ETIMEDOUT);
__pthread_spin_lock (&mutex->__lock);
if (self->prevp)
__pthread_dequeue (self);
__pthread_spin_unlock (&mutex->__lock);
return err;
}
}
else
__pthread_block (self);
#ifndef NDEBUG
assert (mutex->owner == self);
#endif
if (mutex->attr)
switch (mutex->attr->mutex_type)
{
case PTHREAD_MUTEX_NORMAL:
break;
case PTHREAD_MUTEX_RECURSIVE:
assert (mutex->locks == 0);
mutex->locks = 1;
case PTHREAD_MUTEX_ERRORCHECK:
mutex->owner = self;
break;
default:
LOSE;
}
return 0;
}
int
pthread_mutex_timedlock (struct __pthread_mutex *mutex,
const struct timespec *abstime)
{
return __pthread_mutex_timedlock_internal (mutex, abstime);
}
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