144 lines
4.8 KiB
C
144 lines
4.8 KiB
C
/************************************************************************
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* sched/sched_getparam.c
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*
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* Copyright (C) 2007, 2009 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 <sched.h>
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#include "os_internal.h"
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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 Function Prototypes
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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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* Name: sched_getparam
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*
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* Description:
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* This function gets the scheduling priority of the task
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* specified by pid.
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*
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* Inputs:
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* pid - the task ID of the task. If pid is zero, the priority
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* of the calling task is returned.
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* param - A structure whose member sched_priority is the integer
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* priority. The task's priority is copied to the sched_priority
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* element of this structure.
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*
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* Return Value:
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* 0 (OK) if successful, otherwise -1 (ERROR).
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*
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* This function can fail if param is null or if pid does
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* not correspond to any task.
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*
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* Assumptions:
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*
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************************************************************************/
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int sched_getparam (pid_t pid, struct sched_param * param)
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{
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FAR _TCB *rtcb;
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FAR _TCB *tcb;
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int ret = OK;
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if (!param)
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{
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return ERROR;
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}
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/* Check if the task to restart is the calling task */
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rtcb = (FAR _TCB*)g_readytorun.head;
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if ((pid == 0) || (pid == rtcb->pid))
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{
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/* Return the priority if the calling task. */
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param->sched_priority = (int)rtcb->sched_priority;
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}
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/* Ths pid is not for the calling task, we will have to look it up */
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else
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{
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/* Get the TCB associated with this pid */
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sched_lock();
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tcb = sched_gettcb(pid);
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if (!tcb)
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{
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/* This pid does not correspond to any known task */
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ret = ERROR;
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}
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else
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{
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/* Return the priority of the task */
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param->sched_priority = (int)tcb->sched_priority;
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}
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sched_unlock();
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}
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return ret;
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}
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