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nuttx/sched/group_leave.c
patacongo 5475d02446 Move list of open message queues to task group. Now message queues opened by members of the group will be closed when the last member of the group exits. 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5609 42af7a65-404d-4744-a932-0658087f49c3
2013-02-04 16:55:38 +00:00

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/*****************************************************************************
* sched/group_leave.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/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/lib.h>
#include "env_internal.h"
#include "pthread_internal.h"
#include "mq_internal.h"
#include "group_internal.h"
#ifdef HAVE_TASK_GROUP
/*****************************************************************************
* Pre-processor Definitions
*****************************************************************************/
/*****************************************************************************
* Private Types
*****************************************************************************/
/*****************************************************************************
* Private Data
*****************************************************************************/
/*****************************************************************************
* Private Functions
*****************************************************************************/
/*****************************************************************************
* Name: group_remove
*
* Description:
* Remove a group from the list of groups.
*
* Parameters:
* group - The group to be removed.
*
* Return Value:
* None.
*
* Assumptions:
* Called during task deletion in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
void group_remove(FAR struct task_group_s *group)
{
FAR struct task_group_s *curr;
FAR struct task_group_s *prev;
irqstate_t flags;
/* Let's be especially careful while access the global task group list.
* This is probably un-necessary.
*/
flags = irqsave();
/* Find the task group structure */
for (prev = NULL, curr = g_grouphead;
curr && curr != group;
prev = curr, curr = curr->flink);
/* Did we find it? If so, remove it from the list. */
if (curr)
{
/* Do we remove it from mid-list? Or from the head of the list? */
if (prev)
{
prev->flink = curr->flink;
}
else
{
g_grouphead = curr->flink;
}
curr->flink = NULL;
}
irqrestore(flags);
}
#endif
/*****************************************************************************
* Name: group_release
*
* Description:
* Release group resources after the last member has left the group.
*
* Parameters:
* group - The group to be removed.
*
* Return Value:
* None.
*
* Assumptions:
* Called during task deletion in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
static inline void group_release(FAR struct task_group_s *group)
{
/* Free all un-reaped child exit status */
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
group_removechildren(group);
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Release pthread resources */
pthread_release(group);
#endif
/* Free all file-related resources now. We really need to close files as
* soon as possible while we still have a functioning task.
*/
#if CONFIG_NFILE_DESCRIPTORS > 0
/* Free resources held by the file descriptor list */
files_releaselist(&group->tg_filelist);
#if CONFIG_NFILE_STREAMS > 0
/* Free resource held by the stream list */
lib_releaselist(&group->tg_streamlist);
#endif /* CONFIG_NFILE_STREAMS */
#endif /* CONFIG_NFILE_DESCRIPTORS */
#if CONFIG_NSOCKET_DESCRIPTORS > 0
/* Free resource held by the socket list */
net_releaselist(&group->tg_socketlist);
#endif /* CONFIG_NSOCKET_DESCRIPTORS */
/* Release all shared environment variables */
#ifndef CONFIG_DISABLE_ENVIRON
env_release(group);
#endif
/* Close message queues opened by members of the group */
#ifndef CONFIG_DISABLE_MQUEUE
mq_release(group);
#endif
#ifdef HAVE_GROUP_MEMBERS
/* Remove the group from the list of groups */
group_remove(group);
/* Release the members array */
if (group->tg_members)
{
sched_free(group->tg_members);
group->tg_members = NULL;
}
#endif
/* Release the group container itself */
sched_free(group);
}
/*****************************************************************************
* Public Functions
*****************************************************************************/
/*****************************************************************************
* Name: group_leave
*
* Description:
* Release a reference on a group. This function is called when a task or
* thread exits. It decrements the reference count on the group. If the
* reference count decrements to zero, then it frees the group and all of
* resources contained in the group.
*
* Parameters:
* tcb - The TCB of the task that is exiting.
*
* Return Value:
* None.
*
* Assumptions:
* Called during task deletion in a safe context. No special precautions
* are required here.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
void group_leave(FAR _TCB *tcb)
{
FAR struct task_group_s *group;
DEBUGASSERT(tcb);
/* Make sure that we have a group */
group = tcb->group;
if (group)
{
/* Remove the member from group */
int ret = group_removemember(group, tcb->pid);
DEBUGASSERT(ret >= 0);
/* Is the group now empty? */
if (ret == 0)
{
/* Release all of the resource held by the task group */
group_release(group);
}
/* In any event, we can detach the group from the TCB so that we won't
* do this again.
*/
tcb->group = NULL;
}
}
#else /* HAVE_GROUP_MEMBERS */
void group_leave(FAR _TCB *tcb)
{
FAR struct task_group_s *group;
DEBUGASSERT(tcb);
/* Make sure that we have a group */
group = tcb->group;
if (group)
{
/* Yes, we have a group.. Is this the last member of the group? */
if (group->tg_nmembers > 1)
{
/* No.. just decrement the number of members in the group */
group->tg_nmembers--;
}
/* Yes.. that was the last member remaining in the group */
else
{
/* Release all of the resource held by the task group */
group_release(group);
}
/* In any event, we can detach the group from the TCB so we won't do
* this again.
*/
tcb->group = NULL;
}
}
#endif /* HAVE_GROUP_MEMBERS */
/*****************************************************************************
* Name: group_removemember
*
* Description:
* Remove a member from a group.
*
* Parameters:
* group - The group from which to remove the member.
* pid - The member to be removed.
*
* Return Value:
* On success, returns the number of members remaining in the group (>=0).
* Can fail only if the member is not found in the group. On failure,
* returns -ENOENT
*
* Assumptions:
* Called during task deletion and also from the reparenting logic, both
* in a safe context. No special precautions are required here.
*
*****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
int group_removemember(FAR struct task_group_s *group, pid_t pid)
{
int i;
DEBUGASSERT(group);
/* Find the member in the array of members and remove it */
for (i = 0; i < group->tg_nmembers; i++)
{
/* Does this member have the matching pid */
if (group->tg_members[i] == pid)
{
/* Yes.. break out of the loop. We don't do the actual
* removal here, instead we re-test i and do the adjustments
* outside of the loop. We do this because we want the
* DEBUGASSERT to work properly.
*/
break;
}
}
/* Now, test if we found the task in the array of members. */
if (i < group->tg_nmembers)
{
/* Remove the member from the array of members */
group->tg_members[i] = group->tg_members[group->tg_nmembers - 1];
group->tg_nmembers--;
return group->tg_nmembers;
}
return -ENOENT;
}
#endif /* HAVE_GROUP_MEMBERS */
#endif /* HAVE_TASK_GROUP */
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