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/****************************************************************************
* sched/pthread_initialize.c
*
* Copyright (C) 2007-2010 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <semaphore.h>
#include <errno.h>
#include "pthread_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/* This is the head of a private singly linked list. It
* is used to retain information about the spawned threads.
*/
FAR join_t *g_pthread_head = NULL;
FAR join_t *g_pthread_tail = NULL;
/* Mutually exclusive access to this data set is enforced with
* the following (un-named) semaphore.
*/
sem_t g_join_semaphore;
/* This keys track of the number of global keys that have been
* allocated.
*/
uint8_t g_pthread_num_keys;
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_initialize
*
* Description:
* This is an internal OS function called only at power-up boot time.
*
* Parameters:
* None
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
void pthread_initialize(void)
{
/* Initialize some global variables */
g_pthread_head = NULL;
g_pthread_tail = NULL;
g_pthread_num_keys = 0;
/* Initialize the join semaphore to one (to support one-at-
* a-time access to private data sets).
*/
(void)sem_init(&g_join_semaphore, 0, 1);
}
/****************************************************************************
* Name: pthread_takesemaphore and pthread_givesemaphore
*
* Description:
* Support managed access to the private data sets.
*
* Parameters:
* None
*
* Return Value:
* 0 on success or an ERROR on failure with errno value set to EINVAL.
* Note that the errno EINTR is never returned by this function.
*
* Assumptions:
*
****************************************************************************/
int pthread_takesemaphore(sem_t *sem)
{
/* Verify input parameters */
if (sem)
{
/* Take the semaphore */
while (sem_wait(sem) != OK)
{
/* Handle the special case where the semaphore wait was
* awakened by the receipt of a signal.
*/
if (get_errno() != EINTR)
{
set_errno(EINVAL);
return ERROR;
}
}
return OK;
}
else
{
/* NULL semaphore pointer! */
set_errno(EINVAL);
return ERROR;
}
}
int pthread_givesemaphore(sem_t *sem)
{
/* Verify input parameters */
if (sem)
{
/* Give the semaphore */
if (sem_post(sem) == OK)
{
return OK;
}
else
{
/* sem_post() reported an error */
set_errno(EINVAL);
return ERROR;
}
}
else
{
/* NULL semaphore pointer! */
set_errno(EINVAL);
return ERROR;
}
}
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