709263b6d8
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@837 42af7a65-404d-4744-a932-0658087f49c3
87 lines
3.2 KiB
C
87 lines
3.2 KiB
C
/****************************************************************************
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* lib/lib_cwdsem.c
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*
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* Copyright (C) 2008 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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 <sys/types.h>
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#include <unistd.h>
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#include <assert.h>
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#include <semaphore.h>
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#include <errno.h>
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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#if CONFIG_NFILE_DESCRIPTORS > 0
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static sem_t g_cwdsem = { 1 };
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: cwd_semtake
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****************************************************************************/
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void cwd_semtake(void)
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{
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/* Take the semaphore (perhaps waiting) */
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while (sem_wait(&g_cwdsem) != 0)
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{
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/* The only case that an error should occr here is if the wait was
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* awakened by a signal.
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*/
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ASSERT(errno == EINTR);
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}
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}
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/****************************************************************************
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* Name: cwd_semgive
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****************************************************************************/
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void cwd_semgive(void)
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{
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/* Give the semaphore */
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(void)sem_post(&g_cwdsem);
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}
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#endif /* CONFIG_NFILE_DESCRIPTORS */
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