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waitpid(): Corrects two problems when CONFIG_SCHED_HAVE_PARENT+CONFIG_SCHED_CHILD_STATUS are enabled: (1) Was erroring out if the waited for task had already exited, and (2) was not freeing resources when a wait was completed.

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Boris Astardzhiev 2017-09-04 17:10:37 -06:00 committed by Gregory Nutt
parent 7fe3625382
commit 087a0cf2c7
1 changed files with 27 additions and 10 deletions
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37
sched/sched/sched_waitpid.c
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@ -1,7 +1,7 @@
/**************************************************************************** /****************************************************************************
* sched/sched/sched_waitpid.c * sched/sched/sched_waitpid.c
* *
* Copyright (C) 2011-2013, 2015 Gregory Nutt. All rights reserved. * Copyright (C) 2011-2013, 2015, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org> * Author: Gregory Nutt <gnutt@nuttx.org>
* *
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
@ -355,27 +355,33 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options)
} }
else if (pid != (pid_t)-1) else if (pid != (pid_t)-1)
{ {
/* Get the TCB corresponding to this PID and make sure that the /* Get the TCB corresponding to this PID. NOTE: If the child has
* thread it is our child. * already exited, then the PID will not map to a valid TCB.
*/ */
ctcb = sched_gettcb(pid); ctcb = sched_gettcb(pid);
if (ctcb != NULL)
{
/* Make sure that the thread it is our child. */
#ifdef HAVE_GROUP_MEMBERS #ifdef HAVE_GROUP_MEMBERS
if (ctcb == NULL || ctcb->group->tg_pgid != rtcb->group->tg_gid) if (ctcb->group->tg_pgid != rtcb->group->tg_gid)
#else #else
if (ctcb == NULL || ctcb->group->tg_ppid != rtcb->pid) if (ctcb->group->tg_ppid != rtcb->pid)
#endif #endif
{ {
errcode = ECHILD; errcode = ECHILD;
goto errout_with_errno; goto errout_with_errno;
}
} }
/* Does this task retain child status? */ /* The child task is ours or it is no longer active. Does the parent
* task retain child status?
*/
if (retains) if (retains)
{ {
/* Check if this specific pid has allocated child status? */ /* Yes.. Check if this specific pid has allocated child status? */
if (group_findchild(rtcb->group, pid) == NULL) if (group_findchild(rtcb->group, pid) == NULL)
{ {
@ -537,6 +543,17 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options)
*stat_loc = info.si_status << 8; *stat_loc = info.si_status << 8;
pid = info.si_pid; pid = info.si_pid;
#ifdef CONFIG_SCHED_CHILD_STATUS
if (retains)
{
/* Discard the child entry */
(void)group_removechild(rtcb->group, child->ch_pid);
group_freechild(child);
}
#endif /* CONFIG_SCHED_CHILD_STATUS */
break; break;
} }
} }