108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/* Unlock a mutex. Generic version.
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Copyright (C) 2000-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <pthread.h>
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#include <pt-internal.h>
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#define LOSE do { * (int *) 0 = 0; } while (1)
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/* Unlock MUTEX, rescheduling a waiting thread. */
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int
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__pthread_mutex_unlock (pthread_mutex_t *mutex)
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{
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struct __pthread *wakeup;
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const struct __pthread_mutexattr *attr = mutex->__attr;
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if (attr == __PTHREAD_ERRORCHECK_MUTEXATTR)
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attr = &__pthread_errorcheck_mutexattr;
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if (attr == __PTHREAD_RECURSIVE_MUTEXATTR)
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attr = &__pthread_recursive_mutexattr;
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__pthread_spin_lock (&mutex->__lock);
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if (attr == NULL || attr->__mutex_type == PTHREAD_MUTEX_NORMAL)
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{
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#if defined(ALWAYS_TRACK_MUTEX_OWNER)
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# ifndef NDEBUG
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if (_pthread_self ())
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{
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assert (mutex->__owner);
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assert (mutex->__owner == _pthread_self ());
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mutex->__owner = NULL;
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}
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# endif
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#endif
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}
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else
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switch (attr->__mutex_type)
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{
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case PTHREAD_MUTEX_ERRORCHECK:
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case PTHREAD_MUTEX_RECURSIVE:
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if (mutex->__owner != _pthread_self ())
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{
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__pthread_spin_unlock (&mutex->__lock);
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return EPERM;
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}
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if (attr->__mutex_type == PTHREAD_MUTEX_RECURSIVE)
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if (--mutex->__locks > 0)
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{
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__pthread_spin_unlock (&mutex->__lock);
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return 0;
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}
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mutex->__owner = 0;
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break;
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default:
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LOSE;
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}
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if (mutex->__queue == NULL)
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{
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__pthread_spin_unlock (&mutex->__held);
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__pthread_spin_unlock (&mutex->__lock);
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return 0;
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}
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wakeup = mutex->__queue;
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__pthread_dequeue (wakeup);
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#ifndef NDEBUG
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# if !defined (ALWAYS_TRACK_MUTEX_OWNER)
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if (attr != NULL && attr->__mutex_type != PTHREAD_MUTEX_NORMAL)
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# endif
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{
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mutex->__owner = wakeup;
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}
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#endif
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/* We do not unlock MUTEX->held: we are transferring the ownership
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to the thread that we are waking up. */
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__pthread_spin_unlock (&mutex->__lock);
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__pthread_wakeup (wakeup);
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return 0;
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}
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strong_alias (__pthread_mutex_unlock, _pthread_mutex_unlock);
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strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock);
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