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/****************************************************************************
* sched/task/task_start.c
*
* Copyright (C) 2007-2010, 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <nuttx/config.h>
#include <stdlib.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include "sched/sched.h"
#include "task/task.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* This is an artificial limit to detect error conditions where an argv[]
* list is not properly terminated.
*/
#define MAX_START_ARGS 256
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: task_start
*
* Description:
* This function is the low level entry point into the main thread of
* execution of a task. It receives initial control when the task is
* started and calls main entry point of the newly started task.
*
* Inputs:
* None
*
* Return:
* None
*
****************************************************************************/
void task_start(void)
{
FAR struct task_tcb_s *tcb = (FAR struct task_tcb_s*)g_readytorun.head;
int exitcode;
int argc;
DEBUGASSERT((tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD);
/* Execute the start hook if one has been registered */
#ifdef CONFIG_SCHED_STARTHOOK
if (tcb->starthook)
{
tcb->starthook(tcb->starthookarg);
}
#endif
/* Count how many non-null arguments we are passing. The first non-null
* argument terminates the list .
*/
argc = 1;
while (tcb->argv[argc])
{
/* Increment the number of args. Here is a sanity check to
* prevent running away with an unterminated argv[] list.
* MAX_START_ARGS should be sufficiently large that this never
* happens in normal usage.
*/
if (++argc > MAX_START_ARGS)
{
exit(EXIT_FAILURE);
}
}
/* Call the 'main' entry point passing argc and argv. In the kernel build
* this has to be handled differently if we are starting a user-space task;
* we have to switch to user-mode before calling the task.
*/
#if defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)
if ((tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
{
up_task_start(tcb->cmn.entry.main, argc, tcb->argv);
exitcode = EXIT_FAILURE; /* Should not get here */
}
else
#endif
{
exitcode = tcb->cmn.entry.main(argc, tcb->argv);
}
/* Call exit() if/when the task returns */
exit(exitcode);
}
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