incubator-nuttx/sched/get_errno_ptr.c

105 lines
3.4 KiB
C

/************************************************************
* get_errno_ptr.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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 <sched.h>
#include <errno.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#undef get_errno_ptr
/************************************************************
* Private Data
************************************************************/
static int g_irqerrno;
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: get_errno_ptr
*
* Description:
* Return a pointer to the thread specific errno.
*
* Parameters:
* None
*
* Return Value:
* A pointer to the per-thread errno variable.
*
* Assumptions:
*
************************************************************/
FAR int *get_errno_ptr(void)
{
/* Check if this function was called from an interrupt
* handler. In that case, we have to do things a little
* differently.
*/
if (up_interrupt_context())
{
/* Yes, we were called from an interrupt handler. Do
* not permit access to the errno in the TCB of the
* interrupt task. Instead, use a separate errno just
* for interrupt handlers. Of course, this would have
* to change if we ever wanted to support nested
* interrupts.
*/
return &g_irqerrno;
}
else
{
/* We were called from the normal tasking context. Return
* a reference to the thread-private errno in the TCB.
*/
FAR _TCB *ptcb = (FAR _TCB*)g_readytorun.head;
return &ptcb->errno;
}
}