/****************************************************************************
 * sched/pthread/pthread_cancel.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <unistd.h>
#include <pthread.h>
#include <assert.h>
#include <errno.h>

#include <nuttx/tls.h>

#include "sched/sched.h"
#include "task/task.h"
#include "pthread/pthread.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

int pthread_cancel(pthread_t thread)
{
  FAR struct tcb_s *tcb;

  /* First, make sure that the handle references a valid thread */

  if (thread == IDLE_PROCESS_ID)
    {
      /* pid == 0 is the IDLE task (in a single CPU configuration).  Callers
       * cannot cancel the IDLE task.
       */

      return ESRCH;
    }

  tcb = nxsched_get_tcb(thread);
  if (tcb == NULL)
    {
      /* The pid does not correspond to any known thread.  The thread
       * has probably already exited.
       */

      return ESRCH;
    }

  /* Return ESRCH when thread was in exit processing */

  if ((atomic_read(&tcb->flags) & TCB_FLAG_EXIT_PROCESSING) != 0)
    {
      nxsched_put_tcb(tcb);
      return ESRCH;
    }

  /* Only pthreads should use this interface */

  DEBUGASSERT((atomic_read(&tcb->flags) & TCB_FLAG_TTYPE_MASK) ==
               TCB_FLAG_TTYPE_PTHREAD);

  /* Notify the target if the non-cancelable or deferred cancellation set */

  if (nxnotify_cancellation(tcb))
    {
      nxsched_put_tcb(tcb);
      return OK;
    }

  /* Otherwise, perform the asyncrhonous cancellation */

  /* Check to see if the ID refers to ourselves.. this would be the
   * same as pthread_exit(PTHREAD_CANCELED).
   */

  if (tcb == this_task())
    {
      nxsched_put_tcb(tcb);
      pthread_exit(PTHREAD_CANCELED);
    }

  /* Refer to tls_get_info() */

  tls_cleanup_popall(tcb->stack_alloc_ptr);

  nxsched_put_tcb(tcb);

  /* Complete pending join operations */

  pthread_completejoin(thread, PTHREAD_CANCELED);

  /* Then let nxtask_terminate do the real work */

  return nxtask_terminate(thread);
}