107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
/****************************************************************************
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* libs/libc/pthread/pthread_rwlock.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <pthread.h>
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#include <errno.h>
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#include <debug.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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int pthread_rwlock_init(FAR pthread_rwlock_t *lock,
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FAR const pthread_rwlockattr_t *attr)
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{
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int err;
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lock->num_readers = 0;
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lock->num_writers = 0;
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lock->write_in_progress = false;
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err = pthread_cond_init(&lock->cv, NULL);
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if (err != 0)
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{
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return err;
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}
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err = pthread_mutex_init(&lock->lock, NULL);
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if (err != 0)
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{
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pthread_cond_destroy(&lock->cv);
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return err;
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}
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return err;
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}
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int pthread_rwlock_destroy(FAR pthread_rwlock_t *lock)
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{
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int cond_err = pthread_cond_destroy(&lock->cv);
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int mutex_err = pthread_mutex_destroy(&lock->lock);
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if (mutex_err)
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{
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return mutex_err;
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}
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return cond_err;
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}
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int pthread_rwlock_unlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err;
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err = pthread_mutex_lock(&rw_lock->lock);
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if (err != 0)
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{
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return err;
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}
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if (rw_lock->num_readers > 0)
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{
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rw_lock->num_readers--;
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if (rw_lock->num_readers == 0)
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{
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err = pthread_cond_broadcast(&rw_lock->cv);
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}
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}
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else if (rw_lock->write_in_progress)
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{
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rw_lock->write_in_progress = false;
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err = pthread_cond_broadcast(&rw_lock->cv);
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}
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else
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{
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err = EINVAL;
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}
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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