150 lines
5.2 KiB
C
150 lines
5.2 KiB
C
/**************************************************************************
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* sched/pthread/pthread_cancel.c
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*
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* Copyright (C) 2007, 2009, 2013 Gregory Nutt. All rights 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 <sys/types.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <errno.h>
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#include "sched/sched.h"
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#include "pthread/pthread.h"
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/**************************************************************************
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* Private Definitions
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**************************************************************************/
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/**************************************************************************
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* Private Types
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**************************************************************************/
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/**************************************************************************
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* Private Function Prototypes
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**************************************************************************/
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/**************************************************************************
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* Global Variables
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**************************************************************************/
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/**************************************************************************
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* Private Variables
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**************************************************************************/
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/**************************************************************************
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* Private Functions
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**************************************************************************/
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/**************************************************************************
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* Public Functions
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**************************************************************************/
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int pthread_cancel(pthread_t thread)
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{
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struct tcb_s *tcb;
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/* First, make sure that the handle references a valid thread */
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if (!thread)
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{
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/* pid == 0 is the IDLE task. Callers cannot cancel the
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* IDLE task.
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*/
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return ESRCH;
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}
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tcb = sched_gettcb((pid_t)thread);
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if (!tcb)
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{
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/* The pid does not correspond to any known thread. The thread
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* has probably already exited.
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*/
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return ESRCH;
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}
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/* Check to see if this thread has the non-cancelable bit set in its
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* flags. Suppress context changes for a bit so that the flags are stable.
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* (the flags should not change in interrupt handling.
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*/
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sched_lock();
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if ((tcb->flags & TCB_FLAG_NONCANCELABLE) != 0)
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{
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/* Then we cannot cancel the thread now. Here is how this is
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* supposed to work:
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*
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* "When cancelability is disabled, all cancels are held pending
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* in the target thread until the thread changes the cancelability.
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* When cancelability is deferred, all cancels are held pending in
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* the target thread until the thread changes the cancelability, calls
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* a function which is a cancellation point or calls pthread_testcancel(),
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* thus creating a cancellation point. When cancelability is asynchronous,
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* all cancels are acted upon immediately, interrupting the thread with its
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* processing."
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*/
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tcb->flags |= TCB_FLAG_CANCEL_PENDING;
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sched_unlock();
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return OK;
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}
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sched_unlock();
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/* Check to see if the ID refers to ourselves.. this would be the
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* same as pthread_exit(PTHREAD_CANCELED).
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*/
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if (tcb == (struct tcb_s*)g_readytorun.head)
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{
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pthread_exit(PTHREAD_CANCELED);
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}
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/* Complete pending join operations */
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(void)pthread_completejoin((pid_t)thread, PTHREAD_CANCELED);
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/* Then let pthread_delete do the real work */
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task_delete((pid_t)thread);
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return OK;
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}
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