c9bdadd541
This moves all the public POSIX semaphore functions into libc and with this most of the user-space logic is also moved; namely cancel point and errno handling. This also removes the need for the _SEM_XX macros used to differentiate which API is used per user-/kernel mode. Such macros are henceforth unnecessary.
109 lines
4.5 KiB
C
109 lines
4.5 KiB
C
/****************************************************************************
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* sched/semaphore/sem_timedwait.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 <assert.h>
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#include <nuttx/semaphore.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxsem_timedwait
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*
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* Description:
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* This function will lock the semaphore referenced by sem as in the
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* sem_wait() function. However, if the semaphore cannot be locked without
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* waiting for another process or thread to unlock the semaphore by
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* performing a sem_post() function, this wait will be terminated when the
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* specified timeout expires.
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*
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* The timeout will expire when the absolute time specified by abstime
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* passes, as measured by the clock on which timeouts are based (that is,
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* when the value of that clock equals or exceeds abstime), or if the
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* absolute time specified by abstime has already been passed at the
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* time of the call.
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*
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* This is an internal OS interface. It is functionally equivalent to
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* sem_wait except that:
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*
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* - It is not a cancellation point, and
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* - It does not modify the errno value.
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*
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* Input Parameters:
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* sem - Semaphore object
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* abstime - The absolute time to wait until a timeout is declared.
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*
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* Returned Value:
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* This is an internal OS interface and should not be used by applications.
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* It follows the NuttX internal error return policy: Zero (OK) is
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* returned on success. A negated errno value is returned on failure.
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* That may be one of:
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*
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* EINVAL The sem argument does not refer to a valid semaphore. Or the
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* thread would have blocked, and the abstime parameter specified
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* a nanoseconds field value less than zero or greater than or
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* equal to 1000 million.
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* ETIMEDOUT The semaphore could not be locked before the specified timeout
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* expired.
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* EDEADLK A deadlock condition was detected.
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* EINTR A signal interrupted this function.
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*
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****************************************************************************/
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int nxsem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
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{
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return nxsem_clockwait(sem, CLOCK_REALTIME, abstime);
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}
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/****************************************************************************
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* Name: nxsem_timedwait_uninterruptible
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*
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* Description:
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* This function is wrapped version of nxsem_timedwait(), which is
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* uninterruptible and convenient for use.
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*
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* Input Parameters:
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* sem - Semaphore object
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* abstime - The absolute time to wait until a timeout is declared.
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*
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* Returned Value:
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* EINVAL The sem argument does not refer to a valid semaphore. Or the
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* thread would have blocked, and the abstime parameter specified
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* a nanoseconds field value less than zero or greater than or
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* equal to 1000 million.
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* ETIMEDOUT The semaphore could not be locked before the specified timeout
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* expired.
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* EDEADLK A deadlock condition was detected.
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* ECANCELED May be returned if the thread is canceled while waiting.
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*
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****************************************************************************/
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int nxsem_timedwait_uninterruptible(FAR sem_t *sem,
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FAR const struct timespec *abstime)
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{
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return nxsem_clockwait_uninterruptible(sem, CLOCK_REALTIME, abstime);
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}
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