/* Start thread.  Mach version.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library;  if not, see

   <http://www.gnu.org/licenses/>.  */

#include <assert.h>

#include <errno.h>

#include <string.h>

#include <mach.h>

#include <pt-internal.h>

/* Prepare a wakeup message.  */

static error_t

create_wakeupmsg (struct __pthread *thread)

{

  kern_return_t err;

  /* Build wakeup message.  */

  thread->wakeupmsg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_COPY_SEND, 0);

  thread->wakeupmsg.msgh_size = 0;

  err = __mach_port_allocate (__mach_task_self (), MACH_PORT_RIGHT_RECEIVE,

			      &thread->wakeupmsg.msgh_remote_port);

  if (err)

    return EAGAIN;

  thread->wakeupmsg.msgh_local_port = MACH_PORT_NULL;

  thread->wakeupmsg.msgh_seqno = 0;

  thread->wakeupmsg.msgh_id = 0;

  err = __mach_port_insert_right (__mach_task_self (),

				  thread->wakeupmsg.msgh_remote_port,

				  thread->wakeupmsg.msgh_remote_port,

				  MACH_MSG_TYPE_MAKE_SEND);

  if (err)

    {

      __mach_port_destroy (__mach_task_self (),

			   thread->wakeupmsg.msgh_remote_port);

      return EAGAIN;

    }

  /* No need to queue more than one wakeup message on this port.  */

  __mach_port_set_qlimit (__mach_task_self (),

			  thread->wakeupmsg.msgh_remote_port, 1);

  return 0;

}

/* Allocate any resouces for THREAD.  The new kernel thread should not

   be eligible to be scheduled.  */

int

__pthread_thread_alloc (struct __pthread *thread)

{

  static int do_create;

  error_t err;

  err = create_wakeupmsg (thread);

  if (err)

    return err;

  if (!do_create)

    {

      assert (__pthread_total == 0);

      thread->kernel_thread = __mach_thread_self ();

      do_create = 1;

    }

  else

    {

      err = __thread_create (__mach_task_self (), &thread->kernel_thread);

      if (err)

	{

	  __mach_port_destroy (__mach_task_self (),

			       thread->wakeupmsg.msgh_remote_port);

	  return EAGAIN;

	}

    }

  return 0;

}