incubator-nuttx/sched/task/task_terminate.c

208 lines
6.8 KiB
C

/****************************************************************************
* sched/task/task_terminate.c
*
* Copyright (C) 2007-2009, 2011-2014, 2016 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 <sys/types.h>
#include <assert.h>
#include <queue.h>
#include <errno.h>
#include <nuttx/sched.h>
#include <nuttx/irq.h>
#include <nuttx/sched_note.h>
#include "sched/sched.h"
#ifndef CONFIG_DISABLE_SIGNALS
# include "signal/signal.h"
#endif
#include "task/task.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: task_terminate
*
* Description:
* This function causes a specified task to cease to exist. Its stack and
* TCB will be deallocated. This function is the internal implementation
* of the task_delete() function. It includes and additional parameter
* to determine if blocking is permitted or not.
*
* This function is the final function called all task termination
* sequences. task_terminate() is called only from task_delete() (with
* nonblocking == false) and from task_exit() (with nonblocking == true).
*
* The path through task_exit() supports the final stops of the exit(),
* _exit(), and pthread_exit
*
* - pthread_exit(). Calls _exit()
* - exit(). Calls _exit()
* - _exit(). Calls task_exit() making the currently running task
* non-running. task_exit then calls task_terminate() (with nonblocking
* == true) to terminate the non-running task.
*
* NOTE: that the state of non-blocking is irrelevant when called through
* exit() and pthread_exit(). In those cases task_exithook() has already
* been called with nonblocking == false;
*
* Inputs:
* pid - The task ID of the task to delete. A pid of zero
* signifies the calling task.
* nonblocking - True: The task is an unhealthy, partially torn down
* state and is not permitted to block.
*
* Return Value:
* OK on success; or ERROR on failure
*
* This function can fail if the provided pid does not correspond to a
* task (errno is not set)
*
****************************************************************************/
int task_terminate(pid_t pid, bool nonblocking)
{
FAR struct tcb_s *dtcb;
FAR dq_queue_t *tasklist;
irqstate_t flags;
#ifdef CONFIG_SMP
int cpu;
#endif
int ret;
/* Make sure the task does not become ready-to-run while we are futzing
* with its TCB. Within the critical section, no new task may be started
* or terminated (even in the SMP case).
*/
flags = enter_critical_section();
/* Find for the TCB associated with matching PID */
dtcb = sched_gettcb(pid);
if (!dtcb)
{
/* This PID does not correspond to any known task */
ret = -ESRCH;
goto errout_with_lock;
}
/* Verify our internal sanity */
#ifdef CONFIG_SMP
DEBUGASSERT(dtcb->task_state < NUM_TASK_STATES);
#else
DEBUGASSERT(dtcb->task_state != TSTATE_TASK_RUNNING &&
dtcb->task_state < NUM_TASK_STATES);
#endif
/* Remove the task from the OS's task lists. We must be in a critical
* section and the must must not be running to do this.
*/
#ifdef CONFIG_SMP
/* In the SMP case, the thread may be running on another CPU. If that is
* the case, then we will pause the CPU that the thread is running on.
*/
cpu = sched_cpu_pause(dtcb);
/* Get the task list associated with the thread's state and CPU */
tasklist = TLIST_HEAD(dtcb->task_state, cpu);
#else
/* In the non-SMP case, we can be assured that the task to be terminated
* is not running. get the task list associated with the task state.
*/
tasklist = TLIST_HEAD(dtcb->task_state);
#endif
/* Remove the task from the task list */
dq_rem((FAR dq_entry_t *)dtcb, tasklist);
dtcb->task_state = TSTATE_TASK_INVALID;
/* At this point, the TCB should no longer be accessible to the system */
#ifdef CONFIG_SMP
/* Resume the paused CPU (if any) */
if (cpu >= 0)
{
/* I am not yet sure how to handle a failure here. */
DEBUGVERIFY(up_cpu_resume(cpu));
}
#endif /* CONFIG_SMP */
leave_critical_section(flags);
/* Perform common task termination logic (flushing streams, calling
* functions registered by at_exit/on_exit, etc.). We need to do
* this as early as possible so that higher level clean-up logic
* can run in a healthy tasking environment.
*
* In the case where the task exits via exit(), task_exithook()
* may be called twice.
*
* I suppose EXIT_SUCCESS is an appropriate return value???
*/
task_exithook(dtcb, EXIT_SUCCESS, nonblocking);
/* Since all tasks pass through this function as the final step in their
* exit sequence, this is an appropriate place to inform any instrumentation
* layer that the task no longer exists.
*/
sched_note_stop(dtcb);
/* Deallocate its TCB */
return sched_releasetcb(dtcb, dtcb->flags & TCB_FLAG_TTYPE_MASK);
errout_with_lock:
leave_critical_section(flags);
return ret;
}