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366 lines
9.8 KiB
366 lines
9.8 KiB
/***************************************************************************** |
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* sched/group_leave.c |
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* |
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* Copyright (C) 2013 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Included Files |
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*****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <sched.h> |
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#include <assert.h> |
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#include <errno.h> |
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#include <debug.h> |
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#include <nuttx/fs/fs.h> |
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#include <nuttx/net/net.h> |
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#include <nuttx/lib.h> |
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#include "group_internal.h" |
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#include "env_internal.h" |
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#ifdef HAVE_TASK_GROUP |
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/***************************************************************************** |
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* Pre-processor Definitions |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Private Types |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Private Data |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Private Functions |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Name: group_remove |
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* |
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* Description: |
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* Remove a group from the list of groups. |
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* |
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* Parameters: |
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* group - The group to be removed. |
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* |
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* Return Value: |
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* None. |
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* |
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* Assumptions: |
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* Called during task deletion in a safe context. No special precautions |
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* are required here. |
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* |
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*****************************************************************************/ |
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#ifdef HAVE_GROUP_MEMBERS |
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void group_remove(FAR struct task_group_s *group) |
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{ |
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FAR struct task_group_s *curr; |
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FAR struct task_group_s *prev; |
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irqstate_t flags; |
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/* Let's be especially careful while access the global task group list. |
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* This is probably un-necessary. |
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*/ |
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flags = irqsave(); |
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/* Find the task group structure */ |
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for (prev = NULL, curr = g_grouphead; |
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curr && curr != group; |
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prev = curr, curr = curr->flink); |
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/* Did we find it? If so, remove it from the list. */ |
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if (curr) |
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{ |
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/* Do we remove it from mid-list? Or from the head of the list? */ |
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if (prev) |
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{ |
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prev->flink = curr->flink; |
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} |
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else |
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{ |
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g_grouphead = curr->flink; |
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} |
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curr->flink = NULL; |
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} |
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irqrestore(flags); |
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} |
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#endif |
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/***************************************************************************** |
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* Name: group_release |
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* |
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* Description: |
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* Release group resources after the last member has left the group. |
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* |
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* Parameters: |
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* group - The group to be removed. |
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* |
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* Return Value: |
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* None. |
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* |
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* Assumptions: |
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* Called during task deletion in a safe context. No special precautions |
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* are required here. |
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* |
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*****************************************************************************/ |
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static inline void group_release(FAR struct task_group_s *group) |
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{ |
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/* Free all un-reaped child exit status */ |
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#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS) |
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group_removechildren(group); |
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#endif |
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/* Free all file-related resources now. We really need to close files as |
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* soon as possible while we still have a functioning task. |
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*/ |
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#if CONFIG_NFILE_DESCRIPTORS > 0 |
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/* Free resources held by the file descriptor list */ |
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files_releaselist(&group->tg_filelist); |
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#if CONFIG_NFILE_STREAMS > 0 |
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/* Free resource held by the stream list */ |
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lib_releaselist(&group->tg_streamlist); |
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#endif /* CONFIG_NFILE_STREAMS */ |
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#endif /* CONFIG_NFILE_DESCRIPTORS */ |
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#if CONFIG_NSOCKET_DESCRIPTORS > 0 |
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/* Free resource held by the socket list */ |
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net_releaselist(&group->tg_socketlist); |
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#endif /* CONFIG_NSOCKET_DESCRIPTORS */ |
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/* Release all shared environment variables */ |
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#ifndef CONFIG_DISABLE_ENVIRON |
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env_release(group); |
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#endif |
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#ifdef HAVE_GROUP_MEMBERS |
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/* Remove the group from the list of groups */ |
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group_remove(group); |
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/* Release the members array */ |
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if (group->tg_members) |
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{ |
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sched_free(group->tg_members); |
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group->tg_members = NULL; |
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} |
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#endif |
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/* Release the group container itself */ |
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sched_free(group); |
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} |
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/***************************************************************************** |
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* Public Functions |
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*****************************************************************************/ |
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/***************************************************************************** |
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* Name: group_leave |
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* |
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* Description: |
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* Release a reference on a group. This function is called when a task or |
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* thread exits. It decrements the reference count on the group. If the |
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* reference count decrements to zero, then it frees the group and all of |
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* resources contained in the group. |
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* |
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* Parameters: |
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* tcb - The TCB of the task that is exiting. |
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* |
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* Return Value: |
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* None. |
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* |
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* Assumptions: |
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* Called during task deletion in a safe context. No special precautions |
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* are required here. |
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* |
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*****************************************************************************/ |
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#ifdef HAVE_GROUP_MEMBERS |
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void group_leave(FAR _TCB *tcb) |
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{ |
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FAR struct task_group_s *group; |
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DEBUGASSERT(tcb); |
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/* Make sure that we have a group */ |
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group = tcb->group; |
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if (group) |
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{ |
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/* Remove the member from group */ |
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int ret = group_removemember(group, tcb->pid); |
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DEBUGASSERT(ret >= 0); |
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/* Is the group now empty? */ |
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if (ret == 0) |
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{ |
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/* Release all of the resource held by the task group */ |
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group_release(group); |
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} |
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/* In any event, we can detach the group from the TCB so that we won't |
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* do this again. |
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*/ |
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tcb->group = NULL; |
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} |
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} |
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#else /* HAVE_GROUP_MEMBERS */ |
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void group_leave(FAR _TCB *tcb) |
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{ |
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FAR struct task_group_s *group; |
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DEBUGASSERT(tcb); |
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/* Make sure that we have a group */ |
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group = tcb->group; |
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if (group) |
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{ |
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/* Yes, we have a group.. Is this the last member of the group? */ |
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if (group->tg_nmembers > 1) |
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{ |
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/* No.. just decrement the number of members in the group */ |
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group->tg_nmembers--; |
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} |
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/* Yes.. that was the last member remaining in the group */ |
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else |
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{ |
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/* Release all of the resource held by the task group */ |
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group_release(group); |
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} |
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/* In any event, we can detach the group from the TCB so we won't do |
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* this again. |
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*/ |
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tcb->group = NULL; |
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} |
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} |
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#endif /* HAVE_GROUP_MEMBERS */ |
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/***************************************************************************** |
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* Name: group_removemember |
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* |
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* Description: |
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* Remove a member from a group. |
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* |
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* Parameters: |
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* group - The group from which to remove the member. |
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* pid - The member to be removed. |
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* |
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* Return Value: |
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* On success, returns the number of members remaining in the group (>=0). |
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* Can fail only if the member is not found in the group. On failure, |
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* returns -ENOENT |
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* |
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* Assumptions: |
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* Called during task deletion and also from the reparenting logic, both |
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* in a safe context. No special precautions are required here. |
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* |
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*****************************************************************************/ |
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#ifdef HAVE_GROUP_MEMBERS |
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int group_removemember(FAR struct task_group_s *group, pid_t pid) |
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{ |
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int i; |
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DEBUGASSERT(group); |
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/* Find the member in the array of members and remove it */ |
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for (i = 0; i < group->tg_nmembers; i++) |
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{ |
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/* Does this member have the matching pid */ |
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if (group->tg_members[i] == pid) |
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{ |
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/* Yes.. break out of the loop. We don't do the actual |
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* removal here, instead we re-test i and do the adjustments |
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* outside of the loop. We do this because we want the |
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* DEBUGASSERT to work properly. |
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*/ |
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break; |
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} |
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} |
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/* Now, test if we found the task in the array of members. */ |
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if (i < group->tg_nmembers) |
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{ |
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/* Remove the member from the array of members */ |
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group->tg_members[i] = group->tg_members[group->tg_nmembers - 1]; |
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group->tg_nmembers--; |
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return group->tg_nmembers; |
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} |
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return -ENOENT; |
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} |
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#endif /* HAVE_GROUP_MEMBERS */ |
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#endif /* HAVE_TASK_GROUP */
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