325 lines
11 KiB
C
325 lines
11 KiB
C
/****************************************************************************
|
|
* sched/task/task_cancelpt.c
|
|
*
|
|
* Copyright (C) 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Cancellation Points.
|
|
*
|
|
* Cancellation points shall occur when a thread is executing the following
|
|
* functions:
|
|
*
|
|
* accept() mq_timedsend() putpmsg() sigtimedwait()
|
|
* aio_suspend() msgrcv() pwrite() sigwait()
|
|
* clock_nanosleep() msgsnd() read() sigwaitinfo()
|
|
* close() msync() readv() sleep()
|
|
* connect() nanosleep() recv() system()
|
|
* creat() open() recvfrom() tcdrain()
|
|
* fcntl() pause() recvmsg() usleep()
|
|
* fdatasync() poll() select() wait()
|
|
* fsync() pread() sem_timedwait() waitid()
|
|
* getmsg() pselect() sem_wait() waitpid()
|
|
* getpmsg() pthread_cond_timedwait() send() write()
|
|
* lockf() pthread_cond_wait() sendmsg() writev()
|
|
* mq_receive() pthread_join() sendto()
|
|
* mq_send() pthread_testcancel() sigpause()
|
|
* mq_timedreceive() putmsg() sigsuspend()
|
|
*
|
|
* Each of the above function must call enter_cancellation_point() on entry
|
|
* in order to establish the cancellation point and leave_cancellation_point()
|
|
* on exit. These functions are described below.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sched.h>
|
|
#include <errno.h>
|
|
|
|
#include <nuttx/irq.h>
|
|
#include <nuttx/cancelpt.h>
|
|
|
|
#include "sched/sched.h"
|
|
#include "semaphore/semaphore.h"
|
|
#include "mqueue/mqueue.h"
|
|
#include "task/task.h"
|
|
|
|
#ifdef CONFIG_CANCELLATION_POINTS
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: enter_cancellation_point
|
|
*
|
|
* Description:
|
|
* Called at the beginning of the cancellation point to establish the
|
|
* cancellation point. This function does the following:
|
|
*
|
|
* 1. If deferred cancellation does not apply to this thread, nothing is
|
|
* done, otherwise, it
|
|
* 2. Sets state information in the caller's TCB and increments a nesting
|
|
* count.
|
|
* 3. If this is the outermost nesting level, it checks if there is a
|
|
* pending cancellation and, if so, calls either exit() or
|
|
* pthread_exit(), depending upon the type of the thread.
|
|
*
|
|
* Input Parameters:
|
|
* None
|
|
*
|
|
* Returned Value
|
|
* true is returned if a cancellation is pending but cannot be performed
|
|
* now due to the nesting level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
bool enter_cancellation_point(void)
|
|
{
|
|
FAR struct tcb_s *tcb = this_task();
|
|
bool ret = false;
|
|
|
|
/* Disabling pre-emption should provide sufficient protection. We only
|
|
* need the TCB to be stationary (no interrupt level modification is
|
|
* anticipated).
|
|
*
|
|
* REVISIT: is locking the scheduler sufficent in SMP mode?
|
|
*/
|
|
|
|
sched_lock();
|
|
|
|
/* If cancellation is disabled on this thread or if this thread is using
|
|
* asynchronous cancellation, then do nothing.
|
|
*
|
|
* Special case: if the cpcount count is greater than zero, then we are
|
|
* nested and the above condition was certainly true at the outermost
|
|
* nesting level.
|
|
*/
|
|
|
|
if (((tcb->flags & TCB_FLAG_NONCANCELABLE) == 0 &&
|
|
(tcb->flags & TCB_FLAG_CANCEL_DEFERRED) != 0) ||
|
|
tcb->cpcount > 0)
|
|
{
|
|
/* Check if there is a pending cancellation */
|
|
|
|
if ((tcb->flags & TCB_FLAG_CANCEL_PENDING) != 0)
|
|
{
|
|
/* Yes... return true (if we don't exit here) */
|
|
|
|
ret = true;
|
|
|
|
/* If there is a pending cancellation and we are at the outermost
|
|
* nesting level of cancellation function calls, then exit
|
|
* according to the type of the thread.
|
|
*/
|
|
|
|
if (tcb->cpcount == 0)
|
|
{
|
|
#ifndef CONFIG_DISABLE_PTHREAD
|
|
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
|
|
{
|
|
pthread_exit(PTHREAD_CANCELED);
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Otherwise, indicate that we are at a cancellation point by
|
|
* incrementing the nesting level of the cancellation point
|
|
* functions.
|
|
*/
|
|
|
|
DEBUGASSERT(tcb->cpcount < INT16_MAX);
|
|
tcb->cpcount++;
|
|
}
|
|
|
|
sched_unlock();
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: leave_cancellation_point
|
|
*
|
|
* Description:
|
|
* Called at the end of the cancellation point. This function does the
|
|
* following:
|
|
*
|
|
* 1. If deferred cancellation does not apply to this thread, nothing is
|
|
* done, otherwise, it
|
|
* 2. Clears state information in the caller's TCB and decrements a
|
|
* nesting count.
|
|
* 3. If this is the outermost nesting level, it checks if there is a
|
|
* pending cancellation and, if so, calls either exit() or
|
|
* pthread_exit(), depending upon the type of the thread.
|
|
*
|
|
* Input Parameters:
|
|
* None
|
|
*
|
|
* Returned Value
|
|
* None
|
|
*
|
|
****************************************************************************/
|
|
|
|
void leave_cancellation_point(void)
|
|
{
|
|
FAR struct tcb_s *tcb = this_task();
|
|
|
|
/* Disabling pre-emption should provide sufficient protection. We only
|
|
* need the TCB to be stationary (no interrupt level modification is
|
|
* anticipated).
|
|
*
|
|
* REVISIT: is locking the scheduler sufficent in SMP mode?
|
|
*/
|
|
|
|
sched_lock();
|
|
|
|
/* If cancellation is disabled on this thread or if this thread is using
|
|
* asynchronous cancellation, then do nothing. Here we check only the
|
|
* nesting level: if the cpcount count is greater than zero, then the
|
|
* required condition was certainly true at the outermost nesting level.
|
|
*/
|
|
|
|
if (tcb->cpcount > 0)
|
|
{
|
|
/* Decrement the nesting level. If if would decrement to zero, then
|
|
* we are at the outermost nesting level and may need to do more.
|
|
*/
|
|
|
|
if (tcb->cpcount == 1)
|
|
{
|
|
/* We are no longer at the cancellation point */
|
|
|
|
tcb->cpcount = 0;
|
|
|
|
/* If there is a pending cancellation then just exit according to
|
|
* the type of the thread.
|
|
*/
|
|
|
|
if ((tcb->flags & TCB_FLAG_CANCEL_PENDING) != 0)
|
|
{
|
|
#ifndef CONFIG_DISABLE_PTHREAD
|
|
if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
|
|
{
|
|
pthread_exit(PTHREAD_CANCELED);
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* We are not at the outermost nesting level. Just decrment the
|
|
* nesting level count.
|
|
*/
|
|
|
|
tcb->cpcount--;
|
|
}
|
|
}
|
|
|
|
sched_unlock();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: notify_cancellation
|
|
*
|
|
* Description:
|
|
* Called by task_delete() or pthread_cancel() if the cancellation occurs
|
|
* while we the thread is within the cancellation point. This logic
|
|
* behaves much like sending a signal: It will cause waiting threads
|
|
* to wake up and terminated with ECANCELED. A call to
|
|
* leave_cancellation_point() whould then follow, causing the thread to
|
|
* exit.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void notify_cancellation(FAR struct tcb_s *tcb)
|
|
{
|
|
irqstate_t flags;
|
|
|
|
/* We need perform the following operations from within a critical section
|
|
* because it can compete with interrupt level activity.
|
|
*/
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Make sure that the cancellation pending indication is set. */
|
|
|
|
tcb->flags |= TCB_FLAG_CANCEL_PENDING;
|
|
|
|
/* We only notify the cancellation if (1) the thread has not disabled
|
|
* cancellation, (2) the thread uses the deffered cancellation mode,
|
|
* (3) the thread is waiting within a cancellation point.
|
|
*/
|
|
|
|
if (((tcb->flags & TCB_FLAG_NONCANCELABLE) == 0 &&
|
|
(tcb->flags & TCB_FLAG_CANCEL_DEFERRED) != 0) ||
|
|
tcb->cpcount > 0)
|
|
{
|
|
/* If the thread is blocked waiting for a semaphore, then the thread
|
|
* must be unblocked to handle the cancellation.
|
|
*/
|
|
|
|
if (tcb->task_state == TSTATE_WAIT_SEM)
|
|
{
|
|
sem_waitirq(tcb, ECANCELED);
|
|
}
|
|
|
|
/* If the thread is blocked waiting on a message queue, then the
|
|
* thread must be unblocked to handle the cancellation.
|
|
*/
|
|
|
|
#ifndef CONFIG_DISABLE_MQUEUE
|
|
if (tcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
|
|
tcb->task_state == TSTATE_WAIT_MQNOTFULL)
|
|
{
|
|
mq_waitirq(tcb, ECANCELED);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
leave_critical_section(flags);
|
|
}
|
|
|
|
#endif /* CONFIG_CANCELLATION_POINTS */
|