106 lines
4.0 KiB
C
106 lines
4.0 KiB
C
/************************************************************************
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* sched/task/task_getpid.c
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*
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* Copyright (C) 2007, 2009, 2014 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 <sys/types.h>
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#include <unistd.h>
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#include <sched.h>
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#include "sched/sched.h"
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#include "task/task.h"
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/************************************************************************
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* Pre-processor 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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* Public Functions
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************************************************************************/
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/************************************************************************
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* Name: getpid
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*
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* Description:
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* Get the task ID of the currently executing task.
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*
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************************************************************************/
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pid_t getpid(void)
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{
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FAR struct tcb_s *rtcb;
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/* Get the the TCB at the head of the ready-to-run task list. That
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* will be the currently executing task. There is an exception to
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* this: Verify early in the start-up sequence, the g_readytorun
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* list may be empty! This case, of course, the start-up/IDLE thread
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* with pid == 0 must be running.
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*/
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rtcb = (FAR struct tcb_s *)g_readytorun.head;
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if (rtcb)
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{
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/* Return the task ID from the TCB at the head of the ready-to-run
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* task list
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*/
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return rtcb->pid;
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}
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/* We must have been called earlier in the start up sequence from the
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* start-up/IDLE thread before the g_readytorun list has been initialized.
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*/
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return 0;
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}
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