int task_restart(pid_t pid)
{
FAR struct tcb_s *rtcb;
FAR struct task_tcb_s *tcb;
FAR dq_queue_t *tasklist;
irqstate_t state;
int status;
/* Make sure this task does not become ready-to-run while
* we are futzing with its TCB
*/
sched_lock();
/* Check if the task to restart is the calling task */
rtcb = this_task();
if ((pid == 0) || (pid == rtcb->pid))
{
/* Not implemented */
set_errno(ENOSYS);
return ERROR;
}
#ifdef CONFIG_SMP
/* There is currently no capability to restart a task that is actively
* running on another CPU either. This is not the calling cast so if it
* is running, then it could only be running a a different CPU.
*
* Also, will need some interlocks to assure that no tasks are rescheduled
* on any other CPU while we do this.
*/
#warning Missing SMP logic
if (rtcb->task_state == TSTATE_TASK_RUNNING)
{
/* Not implemented */
set_errno(ENOSYS);
return ERROR;
}
#endif
/* We are restarting some other task than ourselves */
/* Find for the TCB associated with matching pid */
tcb = (FAR struct task_tcb_s *)sched_gettcb(pid);
#ifndef CONFIG_DISABLE_PTHREAD
if (!tcb || (tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
#else
if (!tcb)
#endif
{
/* There is no TCB with this pid or, if there is, it is not a task. */
set_errno(ESRCH);
return ERROR;
}
/* Try to recover from any bad states */
task_recover((FAR struct tcb_s *)tcb);
/* Kill any children of this thread */
#ifdef HAVE_GROUP_MEMBERS
(void)group_killchildren(tcb);
#endif
/* Remove the TCB from whatever list it is in. After this point, the TCB
* should no longer be accessible to the system
*/
#ifdef CONFIG_SMP
tasklist = TLIST_HEAD(tcb->cmn.task_state, tcb->cmn.cpu);
#else
tasklist = TLIST_HEAD(tcb->cmn.task_state);
#endif
state = irqsave();
dq_rem((FAR dq_entry_t *)tcb, tasklist);
tcb->cmn.task_state = TSTATE_TASK_INVALID;
irqrestore(state);
/* Deallocate anything left in the TCB's queues */
sig_cleanup((FAR struct tcb_s *)tcb); /* Deallocate Signal lists */
/* Reset the current task priority */
tcb->cmn.sched_priority = tcb->init_priority;
/* Reset the base task priority and the number of pending reprioritizations */
#ifdef CONFIG_PRIORITY_INHERITANCE
tcb->cmn.base_priority = tcb->init_priority;
# if CONFIG_SEM_NNESTPRIO > 0
tcb->cmn.npend_reprio = 0;
# endif
#endif
/* Re-initialize the processor-specific portion of the TCB. This will
* reset the entry point and the start-up parameters
*/
up_initial_state((FAR struct tcb_s *)tcb);
/* Add the task to the inactive task list */
dq_addfirst((FAR dq_entry_t *)tcb, (FAR dq_queue_t *)&g_inactivetasks);
tcb->cmn.task_state = TSTATE_TASK_INACTIVE;
/* Activate the task */
status = task_activate((FAR struct tcb_s *)tcb);
if (status != OK)
{
(void)task_delete(pid);
set_errno(-status);
return ERROR;
}
sched_unlock();
return OK;
}
void task_exithook(FAR struct tcb_s *tcb, int status, bool nonblocking)
{
/* Under certain conditions, task_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;
}
#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)
{
task_atexit(tcb);
/* Call any registered on_exit function(s) */
task_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.
*/
task_recover(tcb);
/* Send the SIGCHILD signal to the parent task group */
task_signalparent(tcb, status);
/* Wakeup any tasks waiting for this task to exit */
task_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)
{
task_flushstreams(tcb);
}
#ifdef HAVE_TASK_GROUP
/* Leave the task group. Perhaps discarding any un-reaped child
* status (no zombies here!)
*/
group_leave(tcb);
#endif
#ifndef CONFIG_DISABLE_SIGNALS
/* Deallocate anything left in the TCB's queues */
sig_cleanup(tcb); /* Deallocate Signal lists */
#endif
/* 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;
}
int task_restart(pid_t pid)
{
FAR struct tcb_s *rtcb;
FAR struct task_tcb_s *tcb;
FAR dq_queue_t *tasklist;
irqstate_t flags;
int errcode;
#ifdef CONFIG_SMP
int cpu;
#endif
int ret;
/* Check if the task to restart is the calling task */
rtcb = this_task();
if ((pid == 0) || (pid == rtcb->pid))
{
/* Not implemented */
errcode = ENOSYS;
goto errout;
}
/* We are restarting some other task than ourselves. Make sure that the
* task does not change its state while we are executing. In the single
* CPU state this could be done by disabling pre-emption. But we will
* a little stronger medicine on the SMP case: The task make be running
* on another CPU.
*/
flags = enter_critical_section();
/* Find for the TCB associated with matching pid */
tcb = (FAR struct task_tcb_s *)sched_gettcb(pid);
#ifndef CONFIG_DISABLE_PTHREAD
if (!tcb || (tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
#else
if (!tcb)
#endif
{
/* There is no TCB with this pid or, if there is, it is not a task. */
errcode = ESRCH;
goto errout_with_lock;
}
#ifdef CONFIG_SMP
/* If the task is running on another CPU, then pause that CPU. We can
* then manipulate the TCB of the restarted task and when we resume the
* that CPU, the restart take effect.
*/
cpu = sched_cpu_pause(&tcb->cmn);
#endif /* CONFIG_SMP */
/* Try to recover from any bad states */
task_recover((FAR struct tcb_s *)tcb);
/* Kill any children of this thread */
#ifdef HAVE_GROUP_MEMBERS
(void)group_killchildren(tcb);
#endif
/* Remove the TCB from whatever list it is in. After this point, the TCB
* should no longer be accessible to the system
*/
#ifdef CONFIG_SMP
tasklist = TLIST_HEAD(tcb->cmn.task_state, tcb->cmn.cpu);
#else
tasklist = TLIST_HEAD(tcb->cmn.task_state);
#endif
dq_rem((FAR dq_entry_t *)tcb, tasklist);
tcb->cmn.task_state = TSTATE_TASK_INVALID;
/* Deallocate anything left in the TCB's queues */
sig_cleanup((FAR struct tcb_s *)tcb); /* Deallocate Signal lists */
/* Reset the current task priority */
tcb->cmn.sched_priority = tcb->cmn.init_priority;
/* The task should restart with pre-emption disabled and not in a critical
* secton.
*/
tcb->cmn.lockcount = 0;
#ifdef CONFIG_SMP
tcb->cmn.irqcount = 0;
#endif
/* Reset the base task priority and the number of pending reprioritizations */
#ifdef CONFIG_PRIORITY_INHERITANCE
tcb->cmn.base_priority = tcb->cmn.init_priority;
# if CONFIG_SEM_NNESTPRIO > 0
tcb->cmn.npend_reprio = 0;
# endif
#endif
/* Re-initialize the processor-specific portion of the TCB. This will
* reset the entry point and the start-up parameters
*/
up_initial_state((FAR struct tcb_s *)tcb);
/* Add the task to the inactive task list */
dq_addfirst((FAR dq_entry_t *)tcb, (FAR dq_queue_t *)&g_inactivetasks);
tcb->cmn.task_state = TSTATE_TASK_INACTIVE;
#ifdef CONFIG_SMP
/* Resume the paused CPU (if any) */
if (cpu >= 0)
{
ret = up_cpu_resume(cpu);
if (ret < 0)
{
errcode = -ret;
goto errout_with_lock;
}
}
#endif /* CONFIG_SMP */
leave_critical_section(flags);
/* Activate the task. */
ret = task_activate((FAR struct tcb_s *)tcb);
if (ret != OK)
{
(void)task_terminate(pid, true);
errcode = -ret;
goto errout_with_lock;
}
return OK;
errout_with_lock:
leave_critical_section(flags);
errout:
set_errno(errcode);
return ERROR;
}
int task_restart(pid_t pid)
{
FAR struct tcb_s *rtcb;
FAR struct task_tcb_s *tcb;
irqstate_t state;
int status;
/* Make sure this task does not become ready-to-run while
* we are futzing with its TCB
*/
sched_lock();
/* Check if the task to restart is the calling task */
rtcb = (FAR struct tcb_s *)g_readytorun.head;
if ((pid == 0) || (pid == rtcb->pid))
{
/* Not implemented */
set_errno(ENOSYS);
return ERROR;
}
/* We are restarting some other task than ourselves */
else
{
/* Find for the TCB associated with matching pid */
tcb = (FAR struct task_tcb_s *)sched_gettcb(pid);
#ifndef CONFIG_DISABLE_PTHREAD
if (!tcb || (tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
#else
if (!tcb)
#endif
{
/* There is no TCB with this pid or, if there is, it is not a
* task.
*/
set_errno(ESRCH);
return ERROR;
}
/* Try to recover from any bad states */
task_recover((FAR struct tcb_s *)tcb);
/* Kill any children of this thread */
#if HAVE_GROUP_MEMBERS
(void)group_killchildren(tcb);
#endif
/* Remove the TCB from whatever list it is in. At this point, the
* TCB should no longer be accessible to the system
*/
state = irqsave();
dq_rem((FAR dq_entry_t*)tcb,
(dq_queue_t*)g_tasklisttable[tcb->cmn.task_state].list);
tcb->cmn.task_state = TSTATE_TASK_INVALID;
irqrestore(state);
/* Deallocate anything left in the TCB's queues */
sig_cleanup((FAR struct tcb_s *)tcb); /* Deallocate Signal lists */
/* Reset the current task priority */
tcb->cmn.sched_priority = tcb->init_priority;
/* Reset the base task priority and the number of pending reprioritizations */
#ifdef CONFIG_PRIORITY_INHERITANCE
tcb->cmn.base_priority = tcb->init_priority;
# if CONFIG_SEM_NNESTPRIO > 0
tcb->cmn.npend_reprio = 0;
# endif
#endif
/* Re-initialize the processor-specific portion of the TCB
* This will reset the entry point and the start-up parameters
*/
up_initial_state((FAR struct tcb_s *)tcb);
/* Add the task to the inactive task list */
dq_addfirst((FAR dq_entry_t*)tcb, (dq_queue_t*)&g_inactivetasks);
tcb->cmn.task_state = TSTATE_TASK_INACTIVE;
/* Activate the task */
status = task_activate((FAR struct tcb_s *)tcb);
if (status != OK)
{
(void)task_delete(pid);
set_errno(-status);
return ERROR;
}
}
sched_unlock();
return OK;
}
