cf99fb40c9
Squashed commit of the following:
libs/libxx: Fix some confusing in naming. If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
libs/: Fix paths in moved library directories.
libs: Brute force move of libc, libnx, and libxx to libs. Cannot yet build it in that configuration.
159 lines
4.3 KiB
C
159 lines
4.3 KiB
C
/****************************************************************************
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* libs/libc/pthread/pthread_rwlock_rdlock.c
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*
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* Copyright (C) 2017 Mark Schulte. All rights reserved.
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* Author: Mark Schulte <mark@mjs.pw>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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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#include <nuttx/semaphore.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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#ifdef CONFIG_PTHREAD_CLEANUP
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static void rdlock_cleanup(FAR void *arg)
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{
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FAR pthread_rwlock_t *rw_lock = (FAR pthread_rwlock_t *)arg;
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(void)pthread_mutex_unlock(&rw_lock->lock);
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}
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#endif
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static int tryrdlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err;
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if (rw_lock->num_writers > 0 || rw_lock->write_in_progress)
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{
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err = EBUSY;
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}
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else if (rw_lock->num_readers == UINT_MAX)
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{
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err = EAGAIN;
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}
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else
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{
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rw_lock->num_readers++;
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err = OK;
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}
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return err;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_rwlock_rdlock
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*
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* Description:
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* Locks a read/write lock for reading
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_rwlock_tryrdlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err = pthread_mutex_trylock(&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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err = tryrdlock(rw_lock);
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_timedrdlock(FAR pthread_rwlock_t *rw_lock,
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FAR const struct timespec *ts)
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{
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int 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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#ifdef CONFIG_PTHREAD_CLEANUP
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pthread_cleanup_push(&rdlock_cleanup, rw_lock);
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#endif
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while ((err = tryrdlock(rw_lock)) == EBUSY)
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{
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if (ts != NULL)
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{
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err = pthread_cond_timedwait(&rw_lock->cv, &rw_lock->lock, ts);
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}
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else
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{
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err = pthread_cond_wait(&rw_lock->cv, &rw_lock->lock);
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}
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if (err != 0)
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{
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break;
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}
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}
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#ifdef CONFIG_PTHREAD_CLEANUP
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pthread_cleanup_pop(0);
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#endif
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_rdlock(FAR pthread_rwlock_t * rw_lock)
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{
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return pthread_rwlock_timedrdlock(rw_lock, NULL);
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}
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