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;
struct tcb_s *tcb;
gid_t ogid;
gid_t pgid;
irqstate_t flags;
int ret;
/* Disable interrupts so that nothing can change in the relatinoship of
* the three task: Child, current parent, and new parent.
*/
flags = irqsave();
/* Get the child tasks task group */
tcb = sched_gettcb(chpid);
if (!tcb)
{
ret = -ECHILD;
goto errout_with_ints;
}
DEBUGASSERT(tcb->group);
chgrp = tcb->group;
/* Get the GID of the old parent task's task group (ogid) */
ogid = chgrp->tg_pgid;
/* Get the old parent task's task group (ogrp) */
ogrp = group_findbygid(ogid);
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) */
pgid = ogrp->tg_pgid;
pgrp = group_findbygid(pgid);
}
else
{
/* Get the new parent task's task group (pgrp) */
tcb = sched_gettcb(ppid);
if (!tcb)
{
ret = -ESRCH;
goto errout_with_ints;
}
pgrp = tcb->group;
pgid = pgrp->tg_gid;
}
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_pgid = pgid;
#ifdef CONFIG_SCHED_CHILD_STATUS
/* Remove the child status entry from old parent task group */
child = group_removechild(ogrp, chpid);
if (child)
{
/* Has the new parent's task group supressed 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_addchild(pgrp, child);
}
else
{
/* Yes.. Discard the child status entry */
group_freechild(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 */
DEBUGASSERT(otcb->nchildren > 0);
otcb->nchildren--; /* The orignal parent now has one few children */
ptcb->nchildren++; /* The new parent has one additional child */
ret = OK;
#endif /* CONFIG_SCHED_CHILD_STATUS */
errout_with_ints:
irqrestore(flags);
return ret;
}
static inline void task_saveparent(FAR struct tcb_s *tcb, uint8_t ttype)
{
FAR struct tcb_s *rtcb = (FAR struct tcb_s*)g_readytorun.head;
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_SCHED_CHILD_STATUS)
DEBUGASSERT(tcb && tcb->group && rtcb->group);
#else
#endif
#ifdef HAVE_GROUP_MEMBERS
/* Save the ID of the parent tasks' task group in the child's task group.
* Do nothing for pthreads. The parent and the child are both members of
* the same task group.
*/
#ifndef CONFIG_DISABLE_PTHREAD
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
#endif
{
/* This is a new task in a new task group, we have to copy the ID from
* the parent's task group structure to child's task group.
*/
tcb->group->tg_pgid = rtcb->group->tg_gid;
}
#else
DEBUGASSERT(tcb);
/* Save the parent task's ID in the child task's TCB. I am not sure if
* this makes sense for the case of pthreads or not, but I don't think it
* is harmful in any event.
*/
tcb->ppid = rtcb->pid;
#endif
#ifdef CONFIG_SCHED_CHILD_STATUS
/* Tasks can also suppress retention of their child status by applying
* the SA_NOCLDWAIT flag with sigaction().
*/
if ((rtcb->group->tg_flags && GROUP_FLAG_NOCLDWAIT) == 0)
{
FAR struct child_status_s *child;
/* Make sure that there is not already a structure for this PID in the
* parent TCB. There should not be.
*/
child = group_findchild(rtcb->group, tcb->pid);
DEBUGASSERT(!child);
if (!child)
{
/* Allocate a new status structure */
child = group_allocchild();
}
/* Did we successfully find/allocate the child status structure? */
DEBUGASSERT(child);
if (child)
{
/* Yes.. Initialize the structure */
child->ch_flags = ttype;
child->ch_pid = tcb->pid;
child->ch_status = 0;
/* Add the entry into the TCB list of children */
group_addchild(rtcb->group, child);
}
}
#else
DEBUGASSERT(rtcb->nchildren < UINT16_MAX);
rtcb->nchildren++;
#endif
}
int task_reparent(pid_t ppid, pid_t chpid)
{
#ifdef CONFIG_SCHED_CHILD_STATUS
FAR struct child_status_s *child;
#endif
struct tcb_s *ptcb;
struct tcb_s *chtcb;
struct tcb_s *otcb;
pid_t opid;
irqstate_t flags;
int ret;
/* Disable interrupts so that nothing can change in the relatinoship of
* the three task: Child, current parent, and new parent.
*/
flags = irqsave();
/* Get the child tasks TCB (chtcb) */
chtcb = sched_gettcb(chpid);
if (!chtcb)
{
ret = -ECHILD;
goto errout_with_ints;
}
/* Get the PID of the child task's parent (opid) */
opid = chtcb->ppid;
/* Get the TCB of the child task's parent (otcb) */
otcb = sched_gettcb(opid);
if (!otcb)
{
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)
{
ppid = otcb->ppid;
}
/* Get the new parent task's TCB (ptcb) */
ptcb = sched_gettcb(ppid);
if (!ptcb)
{
ret = -ESRCH;
goto errout_with_ints;
}
/* Then reparent the child */
chtcb->ppid = ppid; /* The task specified by ppid is the new parent */
#ifdef CONFIG_SCHED_CHILD_STATUS
/* Remove the child status entry from old parent TCB */
child = group_removechild(otcb->group, chpid);
if (child)
{
/* Has the new parent's task group supressed 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_addchild(ptcb->group, child);
}
else
{
/* Yes.. Discard the child status entry */
group_freechild(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 */
DEBUGASSERT(otcb->nchildren > 0);
otcb->nchildren--; /* The orignal parent now has one few children */
ptcb->nchildren++; /* The new parent has one additional child */
ret = OK;
#endif /* CONFIG_SCHED_CHILD_STATUS */
errout_with_ints:
irqrestore(flags);
return ret;
}
