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