incubator-nuttx/sched/group/group_leave.c

436 lines
12 KiB
C

/****************************************************************************
* sched/group/group_leave.c
*
* Copyright (C) 2013-2017 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/irq.h>
#include <nuttx/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/lib/lib.h>
#include "environ/environ.h"
#include "signal/signal.h"
#include "pthread/pthread.h"
#include "mqueue/mqueue.h"
#include "group/group.h"
#ifdef HAVE_TASK_GROUP
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: group_remove
*
* Description:
* Remove a group from the list of groups.
*
* Input Parameters:
* group - The group to be removed.
*
* Returned Value:
* None.
*
* Assumptions:
* Called during task deletion in a safe context. No special precautions
* are required here.
*
****************************************************************************/
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
static 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 = enter_critical_section();
/* 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;
}
leave_critical_section(flags);
}
#endif
/****************************************************************************
* Name: group_release
*
* Description:
* Release group resources after the last member has left the group.
*
* Input Parameters:
* group - The group to be removed.
*
* Returned 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_SIGNALS
/* Release pending signals */
nxsig_release(group);
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Release pthread resources */
pthread_release(group);
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0
/* Free all file-related resources now. We really need to close files as
* soon as possible while we still have a functioning task.
*/
/* 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_stream_release(group);
#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 */
#ifndef CONFIG_DISABLE_ENVIRON
/* Release all shared environment variables */
env_release(group);
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* Close message queues opened by members of the group */
nxmq_release(group);
#endif
#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_SHM)
/* Release any resource held by shared memory virtual page allocator */
(void)shm_group_release(group);
#endif
#ifdef CONFIG_ARCH_ADDRENV
/* Destroy the group address environment */
(void)up_addrenv_destroy(&group->tg_addrenv);
/* Mark no address environment */
g_gid_current = 0;
#endif
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
/* Remove the group from the list of groups */
group_remove(group);
#endif
#ifdef HAVE_GROUP_MEMBERS
/* Release the members array */
if (group->tg_members)
{
sched_kfree(group->tg_members);
group->tg_members = NULL;
}
#endif
#if CONFIG_NFILE_STREAMS > 0 && defined(CONFIG_MM_KERNEL_HEAP)
/* In a flat, single-heap build. The stream list is part of the
* group structure and, hence will be freed when the group structure
* is freed. Otherwise, it is separately allocated an must be
* freed here.
*/
# if defined(CONFIG_BUILD_PROTECTED)
/* In the protected build, the task's stream list is always allocated
* and freed from the single, global user allocator.
*/
sched_ufree(group->tg_streamlist);
# elif defined(CONFIG_BUILD_KERNEL)
/* In the kernel build, the unprivileged process' stream list will be
* allocated from with its per-process, private user heap. But in that
* case, there is no reason to do anything here: That allocation resides
* in the user heap which which be completely freed when we destroy the
* process' address environment.
*/
if ((group->tg_flags & GROUP_FLAG_PRIVILEGED) != 0)
{
/* But kernel threads are different in this build configuration: Their
* stream lists were allocated from the common, global kernel heap and
* must explicitly freed here.
*/
sched_kfree(group->tg_streamlist);
}
# endif
#endif
#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
/* If there are threads waiting for this group to be freed, then we cannot
* yet free the memory resources. Instead just mark the group deleted
* and wait for those threads complete their waits.
*/
if (group->tg_nwaiters > 0)
{
group->tg_flags |= GROUP_FLAG_DELETED;
}
else
#endif
{
/* Release the group container itself */
sched_kfree(group);
}
}
/****************************************************************************
* Name: group_removemember
*
* Description:
* Remove a member from a group.
*
* Input Parameters:
* group - The group from which to remove the member.
* pid - The member to be removed.
*
* Returned 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
static inline void group_removemember(FAR struct task_group_s *group, pid_t pid)
{
irqstate_t flags;
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)
{
/* Remove the member from the array of members. This must be an
* atomic operation because the member array may be accessed from
* interrupt handlers (read-only).
*/
flags = enter_critical_section();
group->tg_members[i] = group->tg_members[group->tg_nmembers - 1];
group->tg_nmembers--;
leave_critical_section(flags);
}
}
}
#endif /* HAVE_GROUP_MEMBERS */
/****************************************************************************
* 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.
*
* Input Parameters:
* tcb - The TCB of the task that is exiting.
*
* Returned 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 struct tcb_s *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. This function may be called
* during certain error handling before the PID has been
* added to the group. In this case tcb->pid will be uninitialized
* group_removemember() will fail.
*/
group_removemember(group, tcb->pid);
/* Have all of the members left the group? */
if (group->tg_nmembers == 0)
{
/* Yes.. 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 struct tcb_s *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 */
#endif /* HAVE_TASK_GROUP */