311 lines
7.6 KiB
C
311 lines
7.6 KiB
C
/****************************************************************************
|
|
* sched/task/task_reparent.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
#include <nuttx/irq.h>
|
|
#include <nuttx/sched.h>
|
|
|
|
#include "sched/sched.h"
|
|
#include "group/group.h"
|
|
#include "task/task.h"
|
|
|
|
#ifdef CONFIG_SCHED_HAVE_PARENT
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: task_reparent
|
|
*
|
|
* Description:
|
|
* Change the parent of a task.
|
|
*
|
|
* Input Parameters:
|
|
* ppid - PID of the new parent task (0 for grandparent, i.e. the parent
|
|
* of the current parent task)
|
|
* chpid - PID of the child to be reparented.
|
|
*
|
|
* Returned Value:
|
|
* 0 (OK) on success; A negated errno value on failure.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifdef HAVE_GROUP_MEMBERS
|
|
int task_reparent(pid_t ppid, pid_t chpid)
|
|
{
|
|
#ifdef CONFIG_SCHED_CHILD_STATUS
|
|
FAR struct child_status_s *child;
|
|
#endif
|
|
FAR struct task_group_s *chgrp;
|
|
FAR struct task_group_s *ogrp;
|
|
FAR struct task_group_s *pgrp;
|
|
FAR struct tcb_s *tcb;
|
|
irqstate_t flags;
|
|
pid_t opid;
|
|
int ret;
|
|
|
|
/* Disable interrupts so that nothing can change in the relationship of
|
|
* the three task: Child, current parent, and new parent.
|
|
*/
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Get the child tasks task group */
|
|
|
|
tcb = nxsched_get_tcb(chpid);
|
|
if (!tcb)
|
|
{
|
|
ret = -ECHILD;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
DEBUGASSERT(tcb->group);
|
|
chgrp = tcb->group;
|
|
|
|
/* Get the PID of the old parent task's task group (opid) */
|
|
|
|
opid = chgrp->tg_ppid;
|
|
|
|
/* Get the old parent task's task group (ogrp) */
|
|
|
|
ogrp = task_getgroup(opid);
|
|
if (!ogrp)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* If new parent task's PID (ppid) is zero, then new parent is the
|
|
* grandparent will be the new parent, i.e., the parent of the current
|
|
* parent task.
|
|
*/
|
|
|
|
if (ppid == 0)
|
|
{
|
|
/* Get the grandparent task's task group (pgrp) */
|
|
|
|
ppid = ogrp->tg_ppid;
|
|
pgrp = task_getgroup(ppid);
|
|
}
|
|
else
|
|
{
|
|
/* Get the new parent task's task group (pgrp) */
|
|
|
|
tcb = nxsched_get_tcb(ppid);
|
|
if (!tcb)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
pgrp = tcb->group;
|
|
ppid = pgrp->tg_pid;
|
|
}
|
|
|
|
if (!pgrp)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Then reparent the child. Notice that we don't actually change the
|
|
* parent of the task. Rather, we change the parent task group for
|
|
* all members of the child's task group.
|
|
*/
|
|
|
|
chgrp->tg_ppid = ppid;
|
|
|
|
#ifdef CONFIG_SCHED_CHILD_STATUS
|
|
/* Remove the child status entry from old parent task group */
|
|
|
|
child = group_remove_child(ogrp, chpid);
|
|
if (child)
|
|
{
|
|
/* Has the new parent's task group suppressed child exit status? */
|
|
|
|
if ((pgrp->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
|
|
{
|
|
/* No.. Add the child status entry to the new parent's task group */
|
|
|
|
group_add_child(pgrp, child);
|
|
}
|
|
else
|
|
{
|
|
/* Yes.. Discard the child status entry */
|
|
|
|
group_free_child(child);
|
|
}
|
|
|
|
/* Either case is a success */
|
|
|
|
ret = OK;
|
|
}
|
|
else
|
|
{
|
|
/* This would not be an error if the original parent's task group has
|
|
* suppressed child exit status.
|
|
*/
|
|
|
|
ret = ((ogrp->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0) ? -ENOENT : OK;
|
|
}
|
|
|
|
#else /* CONFIG_SCHED_CHILD_STATUS */
|
|
/* Child task exit status is not retained */
|
|
|
|
DEBUGASSERT(ogrp->tg_nchildren > 0);
|
|
|
|
ogrp->tg_nchildren--; /* The original parent now has one few children */
|
|
pgrp->tg_nchildren++; /* The new parent has one additional child */
|
|
ret = OK;
|
|
|
|
#endif /* CONFIG_SCHED_CHILD_STATUS */
|
|
|
|
errout_with_ints:
|
|
leave_critical_section(flags);
|
|
return ret;
|
|
}
|
|
#else
|
|
int task_reparent(pid_t ppid, pid_t chpid)
|
|
{
|
|
#ifdef CONFIG_SCHED_CHILD_STATUS
|
|
FAR struct child_status_s *child;
|
|
#endif
|
|
FAR struct tcb_s *ptcb;
|
|
FAR struct tcb_s *chtcb;
|
|
FAR struct tcb_s *otcb;
|
|
pid_t opid;
|
|
irqstate_t flags;
|
|
int ret;
|
|
|
|
/* Disable interrupts so that nothing can change in the relationship of
|
|
* the three task: Child, current parent, and new parent.
|
|
*/
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Get the child tasks TCB (chtcb) */
|
|
|
|
chtcb = nxsched_get_tcb(chpid);
|
|
if (!chtcb)
|
|
{
|
|
ret = -ECHILD;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Get the PID of the child task's parent (opid) */
|
|
|
|
opid = chtcb->group->tg_ppid;
|
|
|
|
/* Get the TCB of the child task's parent (otcb) */
|
|
|
|
otcb = nxsched_get_tcb(opid);
|
|
if (!otcb)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* If new parent task's PID (tg_ppid) is zero, then new parent is the
|
|
* grandparent will be the new parent, i.e., the parent of the current
|
|
* parent task.
|
|
*/
|
|
|
|
if (ppid == 0)
|
|
{
|
|
ppid = otcb->group->tg_ppid;
|
|
}
|
|
|
|
/* Get the new parent task's TCB (ptcb) */
|
|
|
|
ptcb = nxsched_get_tcb(ppid);
|
|
if (!ptcb)
|
|
{
|
|
ret = -ESRCH;
|
|
goto errout_with_ints;
|
|
}
|
|
|
|
/* Then reparent the child. The task specified by ppid is the new
|
|
* parent.
|
|
*/
|
|
|
|
chtcb->group->tg_ppid = ppid;
|
|
|
|
#ifdef CONFIG_SCHED_CHILD_STATUS
|
|
/* Remove the child status entry from old parent TCB */
|
|
|
|
child = group_remove_child(otcb->group, chpid);
|
|
if (child)
|
|
{
|
|
/* Has the new parent's task group suppressed child exit status? */
|
|
|
|
if ((ptcb->group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
|
|
{
|
|
/* No.. Add the child status entry to the new parent's task group */
|
|
|
|
group_add_child(ptcb->group, child);
|
|
}
|
|
else
|
|
{
|
|
/* Yes.. Discard the child status entry */
|
|
|
|
group_free_child(child);
|
|
}
|
|
|
|
/* Either case is a success */
|
|
|
|
ret = OK;
|
|
}
|
|
else
|
|
{
|
|
/* This would not be an error if the original parent's task group has
|
|
* suppressed child exit status.
|
|
*/
|
|
|
|
ret = ((otcb->group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0) ?
|
|
-ENOENT : OK;
|
|
}
|
|
|
|
#else /* CONFIG_SCHED_CHILD_STATUS */
|
|
/* Child task exit status is not retained */
|
|
|
|
DEBUGASSERT(otcb->group != NULL && otcb->group->tg_nchildren > 0);
|
|
|
|
otcb->group->tg_nchildren--; /* The original parent now has one few children */
|
|
ptcb->group->tg_nchildren++; /* The new parent has one additional child */
|
|
ret = OK;
|
|
|
|
#endif /* CONFIG_SCHED_CHILD_STATUS */
|
|
|
|
errout_with_ints:
|
|
leave_critical_section(flags);
|
|
return ret;
|
|
}
|
|
#endif
|
|
#endif /* CONFIG_SCHED_HAVE_PARENT */
|