mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-25 12:11:10 +00:00
04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
112 lines
2.8 KiB
C
112 lines
2.8 KiB
C
/* Try to Lock a mutex. Generic version.
|
|
Copyright (C) 2002-2019 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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <pthread.h>
|
|
|
|
#include <pt-internal.h>
|
|
|
|
#define LOSE do { * (int *) 0 = 0; } while (1)
|
|
|
|
/* Lock MUTEX, return EBUSY if we can't get it. */
|
|
int
|
|
__pthread_mutex_trylock (struct __pthread_mutex *mutex)
|
|
{
|
|
int err;
|
|
struct __pthread *self;
|
|
const struct __pthread_mutexattr *attr = mutex->__attr;
|
|
|
|
if (attr == __PTHREAD_ERRORCHECK_MUTEXATTR)
|
|
attr = &__pthread_errorcheck_mutexattr;
|
|
if (attr == __PTHREAD_RECURSIVE_MUTEXATTR)
|
|
attr = &__pthread_recursive_mutexattr;
|
|
|
|
__pthread_spin_lock (&mutex->__lock);
|
|
if (__pthread_spin_trylock (&mutex->__held) == 0)
|
|
/* Acquired the lock. */
|
|
{
|
|
#if defined(ALWAYS_TRACK_MUTEX_OWNER)
|
|
# ifndef NDEBUG
|
|
self = _pthread_self ();
|
|
if (self != NULL)
|
|
/* 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 == NULL);
|
|
mutex->__owner = _pthread_self ();
|
|
}
|
|
# endif
|
|
#endif
|
|
|
|
if (attr != NULL)
|
|
switch (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;
|
|
}
|
|
|
|
err = EBUSY;
|
|
|
|
if (attr != NULL)
|
|
{
|
|
self = _pthread_self ();
|
|
switch (attr->__mutex_type)
|
|
{
|
|
case PTHREAD_MUTEX_NORMAL:
|
|
break;
|
|
|
|
case PTHREAD_MUTEX_ERRORCHECK:
|
|
/* We could check if MUTEX->OWNER is SELF, however, POSIX
|
|
does not permit pthread_mutex_trylock to return EDEADLK
|
|
instead of EBUSY, only pthread_mutex_lock. */
|
|
break;
|
|
|
|
case PTHREAD_MUTEX_RECURSIVE:
|
|
if (mutex->__owner == self)
|
|
{
|
|
mutex->__locks++;
|
|
err = 0;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
LOSE;
|
|
}
|
|
}
|
|
|
|
__pthread_spin_unlock (&mutex->__lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
strong_alias (__pthread_mutex_trylock, _pthread_mutex_trylock);
|
|
strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock);
|