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