/****************************************************************************
* sched/sem_waitirq.c
*
* Copyright (C) 2007, 2008 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 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 <sys/types.h>
#include <sched.h>
#include <errno.h>
#include <nuttx/arch.h>
#include "sem_internal.h"
/****************************************************************************
* Compilation Switches
****************************************************************************/
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: sem_waitirq
*
* Description:
* This function is called when a signal is received by a
* task that is waiting on a semaphore. According to the
* POSIX spec, "...the calling thread shall not return
* from the call to [sem_wait] until it either locks the
* semaphore or the call is interrupted by a signal."
*
* Parameters:
* wtcb - A pointer to the TCB of the task that is waiting
* on a semphare, but has received a signal instead.
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
void sem_waitirq(FAR _TCB *wtcb)
{
irqstate_t saved_state;
/* Disable interrupts. This is necessary (unfortunately) because an
* interrupt handler may attempt to post the semaphore while we are
* doing this.
*/
saved_state = irqsave();
/* It is possible that an interrupt/context switch beat us to the
* punch and already changed the task's state.
*/
if (wtcb->task_state == TSTATE_WAIT_SEM)
{
/* Indicate that the semaphore wait is over. */
wtcb->waitsem = NULL;
/* Mark the errno value for the thread. */
wtcb->pterrno = EINTR;
/* Restart the task. */
up_unblock_task(wtcb);
}
/* Interrupts may now be enabled. */
irqrestore(saved_state);
}