133 lines
4.5 KiB
C
133 lines
4.5 KiB
C
/************************************************************************
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* sched/sched_getscheduler.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 <gnutt@nuttx.org>
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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 <errno.h>
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#include <nuttx/arch.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_getscheduler
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*
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* Description:
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* sched_getscheduler() returns the scheduling policy currently
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* applied to the task identified by pid. If pid equals zero, the
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* policy of the calling task will be retrieved.
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*
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* Inputs:
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* pid - the task ID of the task to query. If pid is zero, the
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* calling task is queried.
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*
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* Return Value:
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* On success, sched_getscheduler() returns the policy for the task
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* (either SCHED_FIFO or SCHED_RR). On error, ERROR (-1) is
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* returned, and errno is set appropriately:
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*
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* ESRCH The task whose ID is pid could not be found.
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*
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* Assumptions:
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*
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************************************************************************/
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int sched_getscheduler(pid_t pid)
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{
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struct tcb_s *tcb;
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/* Verify that the pid corresponds to a real task */
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if (!pid)
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{
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tcb = (struct tcb_s*)g_readytorun.head;
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}
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else
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{
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tcb = sched_gettcb(pid);
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}
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if (!tcb)
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{
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set_errno(ESRCH);
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return ERROR;
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}
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#if CONFIG_RR_INTERVAL > 0
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else if ((tcb->flags & TCB_FLAG_ROUND_ROBIN) != 0)
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{
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return SCHED_RR;
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}
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#endif
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else
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{
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return SCHED_FIFO;
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}
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}
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