106 lines
4.7 KiB
C
106 lines
4.7 KiB
C
/****************************************************************************
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* libs/libc/pthread/pthread_mutex_lock.c
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*
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* Copyright (C) 2007-2009, 2017, 2019 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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 <pthread.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_mutex_lock
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*
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* Description:
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* The mutex object referenced by mutex is locked by calling
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* pthread_mutex_lock(). If the mutex is already locked, the calling thread
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* blocks until the mutex becomes available. This operation returns with the
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* mutex object referenced by mutex in the locked state with the calling
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* thread as its owner.
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*
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* If the mutex type is PTHREAD_MUTEX_NORMAL, deadlock detection is not
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* provided. Attempting to relock the mutex causes deadlock. If a thread
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* attempts to unlock a mutex that it has not locked or a mutex which is
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* unlocked, undefined behavior results.
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*
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* If the mutex type is PTHREAD_MUTEX_ERRORCHECK, then error checking is
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* provided. If a thread attempts to relock a mutex that it has already
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* locked, an error will be returned. If a thread attempts to unlock a
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* mutex that it has not locked or a mutex which is unlocked, an error will
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* be returned.
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*
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* If the mutex type is PTHREAD_MUTEX_RECURSIVE, then the mutex maintains
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* the concept of a lock count. When a thread successfully acquires a mutex
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* for the first time, the lock count is set to one. Every time a thread
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* relocks this mutex, the lock count is incremented by one. Each time the
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* thread unlocks the mutex, the lock count is decremented by one. When the
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* lock count reaches zero, the mutex becomes available for other threads to
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* acquire. If a thread attempts to unlock a mutex that it has not locked or
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* a mutex which is unlocked, an error will be returned.
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*
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* If a signal is delivered to a thread waiting for a mutex, upon return
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* from the signal handler the thread resumes waiting for the mutex as if
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* it was not interrupted.
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*
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* Input Parameters:
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* mutex - A reference to the mutex to be locked.
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*
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* Returned Value:
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* 0 on success or an errno value on failure. Note that the errno EINTR
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* is never returned by pthread_mutex_lock().
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*
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* Assumptions:
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*
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* POSIX Compatibility:
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* - This implementation does not return EAGAIN when the mutex could not be
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* acquired because the maximum number of recursive locks for mutex has
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* been exceeded.
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*
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****************************************************************************/
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int pthread_mutex_lock(FAR pthread_mutex_t *mutex)
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{
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/* pthread_mutex_lock() is equivalent to pthread_mutex_timedlock() when
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* the absolute time delay is a NULL value.
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*/
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return pthread_mutex_timedlock(mutex, NULL);
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}
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