6a3c2aded6
* Simplify EINTR/ECANCEL error handling 1. Add semaphore uninterruptible wait function 2 .Replace semaphore wait loop with a single uninterruptible wait 3. Replace all sem_xxx to nxsem_xxx * Unify the void cast usage 1. Remove void cast for function because many place ignore the returned value witout cast 2. Replace void cast for variable with UNUSED macro
712 lines
21 KiB
C
712 lines
21 KiB
C
/****************************************************************************
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* sched/task/task_exithook.c
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*
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* Copyright (C) 2011-2013, 2015. 2018-2019 Gregory Nutt. All rights
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* 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 <stdlib.h>
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#include <unistd.h>
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#include <signal.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/sched.h>
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#include <nuttx/fs/fs.h>
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#include "sched/sched.h"
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#include "group/group.h"
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#include "signal/signal.h"
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#include "task/task.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtask_atexit
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*
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* Description:
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* Call any registered atexit function(s)
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*
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****************************************************************************/
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#if defined(CONFIG_SCHED_ATEXIT) && !defined(CONFIG_SCHED_ONEXIT)
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static inline void nxtask_atexit(FAR struct tcb_s *tcb)
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{
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FAR struct task_group_s *group = tcb->group;
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/* Make sure that we have not already left the group. Only the final
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* exiting thread in the task group should trigger the atexit()
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* callbacks.
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*
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* REVISIT: This is a security problem In the PROTECTED and KERNEL builds:
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* We must not call the registered function in supervisor mode! See also
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* on_exit() and pthread_cleanup_pop() callbacks.
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*
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* REVISIT: In the case of task_delete(), the callback would execute in
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* the context the caller of task_delete() cancel, not in the context of
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* the exiting task (or process).
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*/
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if (group && group->tg_nmembers == 1)
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{
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#if defined(CONFIG_SCHED_ATEXIT_MAX) && CONFIG_SCHED_ATEXIT_MAX > 1
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int index;
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/* Call each atexit function in reverse order of registration atexit()
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* functions are registered from lower to higher array indices; they
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* must be called in the reverse order of registration when the task
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* group exits, i.e., from higher to lower indices.
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*/
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for (index = CONFIG_SCHED_ATEXIT_MAX - 1; index >= 0; index--)
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{
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if (group->tg_atexitfunc[index])
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{
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atexitfunc_t func;
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/* Nullify the atexit function to prevent its reuse. */
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func = group->tg_atexitfunc[index];
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group->tg_atexitfunc[index] = NULL;
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/* Call the atexit function */
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(*func)();
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}
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}
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#else
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if (group->tg_atexitfunc)
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{
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atexitfunc_t func;
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/* Nullify the atexit function to prevent its reuse. */
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func = group->tg_atexitfunc;
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group->tg_atexitfunc = NULL;
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/* Call the atexit function */
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(*func)();
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}
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#endif
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}
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}
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#else
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# define nxtask_atexit(tcb)
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#endif
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/****************************************************************************
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* Name: nxtask_onexit
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*
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* Description:
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* Call any registered on_exit function(s)
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_ONEXIT
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static inline void nxtask_onexit(FAR struct tcb_s *tcb, int status)
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{
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FAR struct task_group_s *group = tcb->group;
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/* Make sure that we have not already left the group. Only the final
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* exiting thread in the task group should trigger the atexit()
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* callbacks.
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*
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* REVISIT: This is a security problem In the PROTECTED and KERNEL builds:
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* We must not call the registered function in supervisor mode! See also
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* atexit() and pthread_cleanup_pop() callbacks.
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*
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* REVISIT: In the case of task_delete(), the callback would execute in
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* he context the caller of task_delete() cancel, not in the context of
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* the exiting task (or process).
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*/
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if (group && group->tg_nmembers == 1)
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{
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#if defined(CONFIG_SCHED_ONEXIT_MAX) && CONFIG_SCHED_ONEXIT_MAX > 1
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int index;
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/* Call each on_exit function in reverse order of registration.
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* on_exit() functions are registered from lower to higher array
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* indices; they must be called in the reverse order of registration
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* when the task group exits, i.e., from higher to lower indices.
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*/
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for (index = CONFIG_SCHED_ONEXIT_MAX - 1; index >= 0; index--)
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{
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if (group->tg_onexitfunc[index])
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{
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onexitfunc_t func;
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/* Nullify the on_exit function to prevent its reuse. */
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func = group->tg_onexitfunc[index];
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group->tg_onexitfunc[index] = NULL;
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/* Call the on_exit function */
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(*func)(status, group->tg_onexitarg[index]);
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}
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}
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#else
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if (group->tg_onexitfunc)
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{
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onexitfunc_t func;
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/* Nullify the on_exit function to prevent its reuse. */
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func = group->tg_onexitfunc;
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group->tg_onexitfunc = NULL;
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/* Call the on_exit function */
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(*func)(status, group->tg_onexitarg);
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}
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#endif
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}
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}
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#else
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# define nxtask_onexit(tcb,status)
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#endif
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/****************************************************************************
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* Name: nxtask_exitstatus
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*
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* Description:
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* Report exit status when main task of a task group exits
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_CHILD_STATUS
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static inline void nxtask_exitstatus(FAR struct task_group_s *group,
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int status)
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{
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FAR struct child_status_s *child;
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/* Check if the parent task group has suppressed retention of
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* child exit status information.
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*/
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if ((group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
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{
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/* No.. Find the exit status entry for this task in the parent TCB */
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child = group_findchild(group, getpid());
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if (child)
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{
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#ifndef HAVE_GROUP_MEMBERS
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/* No group members? Save the exit status */
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child->ch_status = status;
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#endif
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/* Save the exit status.. For the case of HAVE_GROUP_MEMBERS,
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* the child status will be as exited until the last member
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* of the task group exits.
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*/
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child->ch_status = status;
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}
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}
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}
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#else
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# define nxtask_exitstatus(group,status)
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/****************************************************************************
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* Name: nxtask_groupexit
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*
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* Description:
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* Mark that the final thread of a child task group as exited.
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_CHILD_STATUS
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static inline void nxtask_groupexit(FAR struct task_group_s *group)
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{
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FAR struct child_status_s *child;
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/* Check if the parent task group has suppressed retention of child exit
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* status information.
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*/
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if ((group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
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{
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/* No.. Find the exit status entry for this task in the parent TCB */
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child = group_findchild(group, getpid());
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if (child)
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{
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/* Mark that all members of the child task group has exited */
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child->ch_flags |= CHILD_FLAG_EXITED;
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}
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}
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}
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#else
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# define nxtask_groupexit(group)
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/****************************************************************************
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* Name: nxtask_sigchild
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*
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* Description:
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* Send the SIGCHILD signal to the parent thread
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_HAVE_PARENT
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#ifdef HAVE_GROUP_MEMBERS
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static inline void nxtask_sigchild(grpid_t pgrpid, FAR struct tcb_s *ctcb,
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int status)
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{
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FAR struct task_group_s *chgrp = ctcb->group;
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FAR struct task_group_s *pgrp;
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siginfo_t info;
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DEBUGASSERT(chgrp);
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/* Get the parent task group. It is possible that all of the members of
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* the parent task group have exited. This would not be an error. In
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* this case, the child task group has been orphaned.
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*/
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pgrp = group_findby_grpid(pgrpid);
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if (!pgrp)
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{
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/* Set the task group ID to an invalid group ID. The dead parent
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* task group ID could get reused some time in the future.
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*/
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chgrp->tg_pgrpid = INVALID_GROUP_ID;
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return;
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}
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/* Save the exit status now if this is the main thread of the task group
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* that is exiting. Only the exiting main task of a task group carries
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* interpretable exit Check if this is the main task that is exiting.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((ctcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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nxtask_exitstatus(pgrp, status);
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}
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/* But only the final exiting thread in a task group, whatever it is,
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* should generate SIGCHLD.
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*/
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if (chgrp->tg_nmembers == 1)
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{
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/* Mark that all of the threads in the task group have exited */
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nxtask_groupexit(pgrp);
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/* Create the siginfo structure. We don't actually know the cause.
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* That is a bug. Let's just say that the child task just exited
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* for now.
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*/
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info.si_signo = SIGCHLD;
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info.si_code = CLD_EXITED;
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info.si_errno = OK;
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info.si_value.sival_ptr = NULL;
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#ifndef CONFIG_DISABLE_PTHREAD
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info.si_pid = chgrp->tg_task;
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#else
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info.si_pid = ctcb->pid;
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#endif
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info.si_status = status;
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/* Send the signal to one thread in the group */
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group_signal(pgrp, &info);
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}
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}
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#else /* HAVE_GROUP_MEMBERS */
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static inline void nxtask_sigchild(FAR struct tcb_s *ptcb,
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FAR struct tcb_s *ctcb, int status)
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{
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siginfo_t info;
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/* If task groups are not supported then we will report SIGCHLD when the
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* task exits. Unfortunately, there could still be threads in the group
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* that are still running.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((ctcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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#ifdef CONFIG_SCHED_CHILD_STATUS
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/* Save the exit status now of the main thread */
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nxtask_exitstatus(ptcb->group, status);
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#else /* CONFIG_SCHED_CHILD_STATUS */
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/* Exit status is not retained. Just decrement the number of
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* children from this parent.
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*/
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DEBUGASSERT(ptcb->group != NULL && ptcb->group->tg_nchildren > 0);
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ptcb->group->tg_nchildren--;
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/* Create the siginfo structure. We don't actually know the cause.
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* That is a bug. Let's just say that the child task just exited
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* for now.
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*/
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info.si_signo = SIGCHLD;
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info.si_code = CLD_EXITED;
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info.si_errno = OK;
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info.si_value.sival_ptr = NULL;
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#ifndef CONFIG_DISABLE_PTHREAD
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info.si_pid = ctcb->group->tg_task;
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#else
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info.si_pid = ctcb->pid;
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#endif
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info.si_status = status;
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/* Send the signal. We need to use this internal interface so that we
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* can provide the correct si_code value with the signal.
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*/
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nxsig_tcbdispatch(ptcb, &info);
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}
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}
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#endif /* HAVE_GROUP_MEMBERS */
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#else /* CONFIG_SCHED_HAVE_PARENT */
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# define nxtask_sigchild(x,ctcb,status)
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#endif /* CONFIG_SCHED_HAVE_PARENT */
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/****************************************************************************
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* Name: nxtask_signalparent
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*
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* Description:
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* Send the SIGCHILD signal to the parent task group
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_HAVE_PARENT
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static inline void nxtask_signalparent(FAR struct tcb_s *ctcb, int status)
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{
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#ifdef HAVE_GROUP_MEMBERS
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DEBUGASSERT(ctcb && ctcb->group);
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/* Keep things stationary throughout the following */
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sched_lock();
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/* Send SIGCHLD to all members of the parent's task group */
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nxtask_sigchild(ctcb->group->tg_pgrpid, ctcb, status);
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sched_unlock();
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#else
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FAR struct tcb_s *ptcb;
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/* Keep things stationary throughout the following */
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sched_lock();
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/* Get the TCB of the receiving, parent task. We do this early to
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* handle multiple calls to nxtask_signalparent.
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*/
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ptcb = sched_gettcb(ctcb->group->tg_ppid);
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if (ptcb == NULL)
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{
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/* The parent no longer exists... bail */
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sched_unlock();
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return;
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}
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/* Send SIGCHLD to all members of the parent's task group. NOTE that the
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* SIGCHLD signal is only sent once either (1) if this is the final thread
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* of the task group that is exiting (HAVE_GROUP_MEMBERS) or (2) if the
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* main thread of the group is exiting (!HAVE_GROUP_MEMBERS).
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*/
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nxtask_sigchild(ptcb, ctcb, status);
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sched_unlock();
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#endif
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}
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#else
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# define nxtask_signalparent(ctcb,status)
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#endif
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/****************************************************************************
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* Name: nxtask_exitwakeup
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*
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* Description:
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* Wakeup any tasks waiting for this task to exit
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*
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****************************************************************************/
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#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
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static inline void nxtask_exitwakeup(FAR struct tcb_s *tcb, int status)
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{
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FAR struct task_group_s *group = tcb->group;
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/* Have we already left the group? */
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if (group)
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{
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/* Only tasks (and kernel threads) return valid status. Record the
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* exit status when the task exists. The group, however, may still
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* be executing.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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/* Report the exit status. We do not nullify tg_statloc here
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* because we want to prevent other tasks from registering for
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* the return status. There is only one task per task group,
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* there for, this logic should execute exactly once in the
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* lifetime of the task group.
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*
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* "If more than one thread is suspended in waitpid() awaiting
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* termination of the same process, exactly one thread will
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* return the process status at the time of the target process
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* termination."
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*
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* Hmmm.. what do we return to the others?
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*/
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if (group->tg_statloc)
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{
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*group->tg_statloc = status << 8;
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}
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}
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/* Is this the last thread in the group? */
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if (group->tg_nmembers == 1)
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{
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/* Yes.. Wakeup any tasks waiting for this task to exit */
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group->tg_statloc = NULL;
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group->tg_waitflags = 0;
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while (group->tg_exitsem.semcount < 0)
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{
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/* Wake up the thread */
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nxsem_post(&group->tg_exitsem);
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}
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}
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}
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}
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#else
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# define nxtask_exitwakeup(tcb, status)
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#endif
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/****************************************************************************
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* Name: nxtask_flushstreams
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*
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* Description:
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* Flush all streams when the final thread of a group exits.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#if CONFIG_NFILE_STREAMS > 0
|
|
static inline void nxtask_flushstreams(FAR struct tcb_s *tcb)
|
|
{
|
|
FAR struct task_group_s *group = tcb->group;
|
|
|
|
/* Have we already left the group? Are we the last thread in the group? */
|
|
|
|
if (group && group->tg_nmembers == 1)
|
|
{
|
|
#if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
|
|
defined(CONFIG_MM_KERNEL_HEAP)
|
|
lib_flushall(tcb->group->tg_streamlist);
|
|
#else
|
|
lib_flushall(&tcb->group->tg_streamlist);
|
|
#endif
|
|
}
|
|
}
|
|
#else
|
|
# define nxtask_flushstreams(tcb)
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxtask_exithook
|
|
*
|
|
* Description:
|
|
* This function implements some of the internal logic of exit() and
|
|
* task_delete(). This function performs some clean-up and other actions
|
|
* required when a task exits:
|
|
*
|
|
* - All open streams are flushed and closed.
|
|
* - All functions registered with atexit() and on_exit() are called, in
|
|
* the reverse order of their registration.
|
|
*
|
|
* When called from exit(), the tcb still resides at the head of the ready-
|
|
* to-run list. The following logic is safe because we will not be
|
|
* returning from the exit() call.
|
|
*
|
|
* When called from nxtask_terminate() we are operating on a different
|
|
* thread; on the thread that called task_delete(). In this case,
|
|
* task_delete will have already removed the tcb from the ready-to-run
|
|
* list to prevent any further action on this task.
|
|
*
|
|
* nonblocking will be set true only when we are called from
|
|
* nxtask_terminate() via _exit(). In that case, we must be careful to do
|
|
* nothing that can cause the cause the thread to block.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void nxtask_exithook(FAR struct tcb_s *tcb, int status, bool nonblocking)
|
|
{
|
|
/* Under certain conditions, nxtask_exithook() can be called multiple times.
|
|
* A bit in the TCB was set the first time this function was called. If
|
|
* that bit is set, then just exit doing nothing more..
|
|
*/
|
|
|
|
if ((tcb->flags & TCB_FLAG_EXIT_PROCESSING) != 0)
|
|
{
|
|
return;
|
|
}
|
|
|
|
#ifdef CONFIG_CANCELLATION_POINTS
|
|
/* Mark the task as non-cancelable to avoid additional calls to exit()
|
|
* due to any cancellation point logic that might get kicked off by
|
|
* actions taken during exit processing.
|
|
*/
|
|
|
|
tcb->flags |= TCB_FLAG_NONCANCELABLE;
|
|
tcb->flags &= ~TCB_FLAG_CANCEL_PENDING;
|
|
tcb->cpcount = 0;
|
|
#endif
|
|
|
|
#if defined(CONFIG_SCHED_ATEXIT) || defined(CONFIG_SCHED_ONEXIT)
|
|
/* If exit function(s) were registered, call them now before we do any un-
|
|
* initialization.
|
|
*
|
|
* NOTES:
|
|
*
|
|
* 1. In the case of task_delete(), the exit function will *not* be called
|
|
* on the thread execution of the task being deleted! That is probably
|
|
* a bug.
|
|
* 2. We cannot call the exit functions if nonblocking is requested: These
|
|
* functions might block.
|
|
* 3. This function will only be called with with non-blocking == true
|
|
* only when called through _exit(). _exit() behaviors requires that
|
|
* the exit functions *not* be called.
|
|
*/
|
|
|
|
if (!nonblocking)
|
|
{
|
|
nxtask_atexit(tcb);
|
|
|
|
/* Call any registered on_exit function(s) */
|
|
|
|
nxtask_onexit(tcb, status);
|
|
}
|
|
#endif
|
|
|
|
/* If the task was terminated by another task, it may be in an unknown
|
|
* state. Make some feeble effort to recover the state.
|
|
*/
|
|
|
|
nxtask_recover(tcb);
|
|
|
|
/* Send the SIGCHILD signal to the parent task group */
|
|
|
|
nxtask_signalparent(tcb, status);
|
|
|
|
/* Wakeup any tasks waiting for this task to exit */
|
|
|
|
nxtask_exitwakeup(tcb, status);
|
|
|
|
/* If this is the last thread in the group, then flush all streams (File
|
|
* descriptors will be closed when the TCB is deallocated).
|
|
*
|
|
* NOTES:
|
|
* 1. We cannot flush the buffered I/O if nonblocking is requested.
|
|
* that might cause this logic to block.
|
|
* 2. This function will only be called with with non-blocking == true
|
|
* only when called through _exit(). _exit() behavior does not
|
|
* require that the streams be flushed
|
|
*/
|
|
|
|
if (!nonblocking)
|
|
{
|
|
nxtask_flushstreams(tcb);
|
|
}
|
|
|
|
/* Leave the task group. Perhaps discarding any un-reaped child
|
|
* status (no zombies here!)
|
|
*/
|
|
|
|
group_leave(tcb);
|
|
|
|
/* Deallocate anything left in the TCB's queues */
|
|
|
|
nxsig_cleanup(tcb); /* Deallocate Signal lists */
|
|
|
|
/* This function can be re-entered in certain cases. Set a flag
|
|
* bit in the TCB to not that we have already completed this exit
|
|
* processing.
|
|
*/
|
|
|
|
tcb->flags |= TCB_FLAG_EXIT_PROCESSING;
|
|
}
|