/************************************************************
* pthread_initialize.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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 <sys/types.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.
*/
join_t *g_pthread_head = NULL;
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.
*/
ubyte g_pthread_num_keys;
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: 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);
}
/************************************************************
* Function: pthread_takesemaphore and pthread_givesemaphore
*
* Description:
* Support managed access to the private data sets.
*
* Parameters:
* None
*
* Return Value:
* None
*
* 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_ptr() != EINTR)
{
*get_errno_ptr() = EINVAL;
return ERROR;
}
}
return OK;
}
else
{
/* NULL semaphore pointer! */
*get_errno_ptr() = 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 */
*get_errno_ptr() = EINVAL;
return ERROR;
}
}
else
{
/* NULL semaphore pointer! */
*get_errno_ptr() = EINVAL;
return ERROR;
}
}
