mirror of
https://github.com/apache/nuttx.git
synced 2026-09-08 09:56:33 +00:00
3888a00d2d
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5531 42af7a65-404d-4744-a932-0658087f49c3
145 lines
4.1 KiB
C
145 lines
4.1 KiB
C
/*****************************************************************************
|
|
* sched/task_reparent.c
|
|
*
|
|
* Copyright (C) 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 <errno.h>
|
|
|
|
#include "os_internal.h"
|
|
|
|
#ifdef CONFIG_SCHED_HAVE_PARENT
|
|
|
|
/*****************************************************************************
|
|
* Private Functions
|
|
*****************************************************************************/
|
|
|
|
/*****************************************************************************
|
|
* Public Functions
|
|
*****************************************************************************/
|
|
|
|
/*****************************************************************************
|
|
* Name: task_reparent
|
|
*
|
|
* Description:
|
|
* Change the parent of a task.
|
|
*
|
|
* Parameters:
|
|
* oldpid - PID of the old parent task (0 if this task)
|
|
* newpid - PID ot the new parent task (0 for the parent of this task)
|
|
* chpid - PID of the child to be reparented.
|
|
*
|
|
* Return Value:
|
|
* 0 (OK) on success; A negated errno value on failure.
|
|
*
|
|
*****************************************************************************/
|
|
|
|
int task_reparent(pid_t oldpid, pid_t newpid, pid_t chpid)
|
|
{
|
|
_TCB *oldtcb;
|
|
_TCB *newtcb;
|
|
_TCB *chtcb;
|
|
irqstate_t flags;
|
|
int ret;
|
|
|
|
/* If oldpid is zero, then we are parent task. */
|
|
|
|
if (oldpid == 0)
|
|
{
|
|
oldpid = getpid();
|
|
}
|
|
|
|
/* Get the current parent task's TCB */
|
|
|
|
oldtcb = sched_gettcb(oldpid);
|
|
if (!oldtcb)
|
|
{
|
|
return -ESRCH;
|
|
}
|
|
|
|
/* Disable interrupts so that nothing can change from this point */
|
|
|
|
flags = irqsave();
|
|
|
|
/* If newpid is zero, then new is the parent of oldpid. */
|
|
|
|
if (newpid == 0)
|
|
{
|
|
newpid = oldtcb->parent;
|
|
}
|
|
|
|
/* Get the new parent task's TCB */
|
|
|
|
newtcb = sched_gettcb(newpid);
|
|
if (!newtcb)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Get the child tasks TCB */
|
|
|
|
chtcb = sched_gettcb(chpid);
|
|
if (!chtcb)
|
|
{
|
|
ret = -ECHILD;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Verify that oldpid is the parent of chpid */
|
|
|
|
if (chtcb->parent != oldpid)
|
|
{
|
|
ret = -ECHILD;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Okay, reparent the child */
|
|
|
|
DEBUGASSERT(oldtcb->nchildren > 0);
|
|
chtcb->parent = newpid;
|
|
oldtcb->nchildren--;
|
|
newtcb->nchildren++;
|
|
ret = OK;
|
|
|
|
errout_with_ints:
|
|
irqrestore(flags);
|
|
return ret;
|
|
}
|
|
|
|
#endif /* CONFIG_SCHED_HAVE_PARENT */
|