void task_exithook(FAR _TCB *tcb, int status)
{
/* If exit function(s) were registered, call them now before we do any un-
* initialization. NOTE: In the case of task_delete(), the exit function
* will *not* be called on the thread execution of the task being deleted!
*/
task_atexit(tcb);
/* Call any registered on_exit function(s) */
task_onexit(tcb, status);
/* Send SIGCHLD to the parent of the exit-ing task */
task_sigchild(tcb, status);
/* Wakeup any tasks waiting for this task to exit */
task_exitwakeup(tcb, status);
/* Flush all streams (File descriptors will be closed when
* the TCB is deallocated).
*/
#if CONFIG_NFILE_STREAMS > 0
(void)lib_flushall(tcb->streams);
#endif
/* Discard any un-reaped child status (no zombies here!) */
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
task_removechildren(tcb);
#endif
/* Free all file-related resources now. This gets called again
* just be be certain when the TCB is delallocated. However, we
* really need to close files as soon as possible while we still
* have a functioning task.
*/
(void)sched_releasefiles(tcb);
/* Deallocate anything left in the TCB's queues */
#ifndef CONFIG_DISABLE_SIGNALS
sig_cleanup(tcb); /* Deallocate Signal lists */
#endif
}
int sched_releasetcb(FAR _TCB *tcb)
{
int ret = OK;
int i;
if (tcb)
{
/* Relase any timers that the task might hold. We do this
* before release the PID because it may still be trying to
* deliver signals (although interrupts are should be
* disabled here).
*/
#ifndef CONFIG_DISABLE_POSIX_TIMERS
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (timer_deleteall != NULL)
#endif
{
timer_deleteall(tcb->pid);
}
#endif
/* Release the task's process ID if one was assigned. PID
* zero is reserved for the IDLE task. The TCB of the IDLE
* task is never release so a value of zero simply means that
* the process ID was never allocated to this TCB.
*/
if (tcb->pid)
{
sched_releasepid(tcb->pid);
}
/* Delete the thread's stack if one has been allocated */
#ifndef CONFIG_CUSTOM_STACK
if (tcb->stack_alloc_ptr)
{
up_release_stack(tcb);
}
#endif
/* Delete the tasks's allocated DSpace region (external modules only) */
#ifdef CONFIG_PIC
if (tcb->dspace)
{
if (tcb->dspace->crefs <= 1)
{
sched_free(tcb->dspace);
}
else
{
tcb->dspace->crefs--;
}
}
#endif
/* Release command line arguments that were allocated for task
* start/re-start.
*/
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_TASK)
{
for (i = 1; i < CONFIG_MAX_TASK_ARGS+1 && tcb->argv[i]; i++)
{
sched_free((FAR void*)tcb->argv[i]);
}
}
/* Release any allocated file structures */
ret = sched_releasefiles(tcb);
/* Release environment variables */
(void)env_release(tcb);
/* And, finally, release the TCB itself */
sched_free(tcb);
}
return ret;
}
static inline void task_atexit(FAR _TCB *tcb)
{
#if defined(CONFIG_SCHED_ATEXIT_MAX) && CONFIG_SCHED_ATEXIT_MAX > 1
int index;
/* Call each atexit function in reverse order of registration atexit()
* functions are registered from lower to higher arry indices; they must
* be called in the reverse order of registration when task exists, i.e.,
* from higher to lower indices.
*/
for (index = CONFIG_SCHED_ATEXIT_MAX-1; index >= 0; index--)
{
if (tcb->atexitfunc[index])
{
/* Call the atexit function */
(*tcb->atexitfunc[index])();
/* Nullify the atexit function. task_exithook may be called more then
* once in most task exit scenarios. Nullifying the atext function
* pointer will assure that the callback is performed only once.
*/
tcb->atexitfunc[index] = NULL;
}
}
#else
if (tcb->atexitfunc)
{
/* Call the atexit function */
(*tcb->atexitfunc)();
/* Nullify the atexit function. task_exithook may be called more then
* once in most task exit scenarios. Nullifying the atext function
* pointer will assure that the callback is performed only once.
*/
tcb->atexitfunc = NULL;
}
#endif
#else
# define task_atexit(tcb)
#endif
/****************************************************************************
* Name: task_onexit
*
* Description:
* Call any registerd on)exit function(s)
*
****************************************************************************/
#ifdef CONFIG_SCHED_ONEXIT
static inline void task_onexit(FAR _TCB *tcb, int status)
{
#if defined(CONFIG_SCHED_ONEXIT_MAX) && CONFIG_SCHED_ONEXIT_MAX > 1
int index;
/* Call each on_exit function in reverse order of registration. on_exit()
* functions are registered from lower to higher arry indices; they must
* be called in the reverse order of registration when task exists, i.e.,
* from higher to lower indices.
*/
for (index = CONFIG_SCHED_ONEXIT_MAX-1; index >= 0; index--)
{
if (tcb->onexitfunc[index])
{
/* Call the on_exit function */
(*tcb->onexitfunc[index])(status, tcb->onexitarg[index]);
/* Nullify the on_exit function. task_exithook may be called more then
* once in most task exit scenarios. Nullifying the atext function
* pointer will assure that the callback is performed only once.
*/
tcb->onexitfunc[index] = NULL;
}
}
#else
if (tcb->onexitfunc)
{
/* Call the on_exit function */
(*tcb->onexitfunc)(status, tcb->onexitarg);
/* Nullify the on_exit function. task_exithook may be called more then
* once in most task exit scenarios. Nullifying the on_exit function
* pointer will assure that the callback is performed only once.
*/
tcb->onexitfunc = NULL;
}
#endif
#else
# define task_onexit(tcb,status)
#endif
/****************************************************************************
* Name: task_exitwakeup
*
* Description:
* Wakeup any tasks waiting for this task to exit
*
****************************************************************************/
#ifdef CONFIG_SCHED_WAITPID
static inline void task_exitwakeup(FAR _TCB *tcb, int status)
{
/* Wakeup any tasks waiting for this task to exit */
while (tcb->exitsem.semcount < 0)
{
/* "If more than one thread is suspended in waitpid() awaiting
* termination of the same process, exactly one thread will return
* the process status at the time of the target process termination."
* Hmmm.. what do we return to the others?
*/
if (tcb->stat_loc)
{
*tcb->stat_loc = status << 8;
tcb->stat_loc = NULL;
}
/* Wake up the thread */
sem_post(&tcb->exitsem);
}
}
#else
# define task_exitwakeup(tcb, status)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: task_hook
*
* Description:
* This function implements some of the internal logic of exit() and
* task_delete(). This function performs some cleanup and other actions
* required when a task exists:
*
* - 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 task_delete() 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.
*
****************************************************************************/
void task_exithook(FAR _TCB *tcb, int status)
{
/* If exit function(s) were registered, call them now before we do any un-
* initialization. NOTE: In the case of task_delete(), the exit function
* will *not* be called on the thread execution of the task being deleted!
*/
task_atexit(tcb);
/* Call any registered on_exit function(s) */
task_onexit(tcb, status);
/* Wakeup any tasks waiting for this task to exit */
task_exitwakeup(tcb, status);
/* Flush all streams (File descriptors will be closed when
* the TCB is deallocated).
*/
#if CONFIG_NFILE_STREAMS > 0
(void)lib_flushall(tcb->streams);
#endif
/* Free all file-related resources now. This gets called again
* just be be certain when the TCB is delallocated. However, we
* really need to close files as soon as possible while we still
* have a functioning task.
*/
(void)sched_releasefiles(tcb);
/* Deallocate anything left in the TCB's queues */
#ifndef CONFIG_DISABLE_SIGNALS
sig_cleanup(tcb); /* Deallocate Signal lists */
#endif
}
