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/*****************************************************************************
* sched/group_find.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 <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include "group_internal.h"
#include "env_internal.h"
#ifdef HAVE_TASK_GROUP
/*****************************************************************************
* Pre-processor Definitions
*****************************************************************************/
/*****************************************************************************
* Private Types
*****************************************************************************/
/*****************************************************************************
* Private Data
*****************************************************************************/
/*****************************************************************************
* Public Data
*****************************************************************************/
/*****************************************************************************
* Private Functions
*****************************************************************************/
/*****************************************************************************
* Public Functions
*****************************************************************************/
/*****************************************************************************
* Name: group_findbygid
*
* Description:
* Given a group ID, find the group task structure with that ID. IDs are
* used instead of pointers to group structures. This is done because a
* group can disappear at any time leaving a stale pointer; an ID is cleaner
* because if the group disappears, this function will fail gracefully.
*
* Parameters:
* gid - The group ID to find.
*
* Return Value:
* On success, a pointer to the group task structure is returned. This
* function can fail only if there is no group that corresponds to the
* group ID.
*
* Assumptions:
* Called during when signally tasks in a safe context. No special
* precautions should be required here. However, extra care is taken when
* accessing the global g_grouphead list.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
FAR struct task_group_s *group_findbygid(gid_t gid)
{
FAR struct task_group_s *group;
irqstate_t flags;
/* Find the status structure with the matching GID */
flags = irqsave();
for (group = g_grouphead; group; group = group->flink)
{
if (group->tg_gid == gid)
{
irqrestore(flags);
return group;
}
}
irqrestore(flags);
return NULL;
}
#endif
/*****************************************************************************
* Name: group_findbygid
*
* Description:
* Given a task ID, find the group task structure with was started by that
* task ID. That task's ID is retained in the group as tg_task and will
* be remember even if the main task thread leaves the group.
*
* Parameters:
* pid - The task ID of the main task thread.
*
* Return Value:
* On success, a pointer to the group task structure is returned. This
* function can fail only if there is no group that corresponds to the
* task ID.
*
* Assumptions:
* Called during when signally tasks in a safe context. No special
* precautions should be required here. However, extra care is taken when
* accessing the global g_grouphead list.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
FAR struct task_group_s *group_findbypid(pid_t pid)
{
FAR struct task_group_s *group;
irqstate_t flags;
/* Find the status structure with the matching PID */
flags = irqsave();
for (group = g_grouphead; group; group = group->flink)
{
if (group->tg_task == pid)
{
irqrestore(flags);
return group;
}
}
irqrestore(flags);
return NULL;
}
#endif
#endif /* HAVE_TASK_GROUP */
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