/* Map thread ID to thread handle.
   Copyright (C) 1999, 2001, 2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include "thread_dbP.h"
#include <linuxthreads/internals.h>


td_err_e
td_ta_map_id2thr (const td_thragent_t *ta, pthread_t pt, td_thrhandle_t *th)
{
  struct pthread_handle_struct phc;
  struct _pthread_descr_struct pds;
  int pthread_threads_max;

  LOG ("td_ta_map_id2thr");

  /* Test whether the TA parameter is ok.  */
  if (! ta_ok (ta))
    return TD_BADTA;

  /* Make the following expression a bit smaller.  */
  pthread_threads_max = ta->pthread_threads_max;

  /* We can compute the entry in the handle array we want.  */
  if (ps_pdread (ta->ph, ta->handles + pt % pthread_threads_max, &phc,
		 sizeof (struct pthread_handle_struct)) != PS_OK)
    return TD_ERR;	/* XXX Other error value?  */

  /* Test whether this entry is in use.  */
  if (phc.h_descr == NULL)
    {
      if (pt % pthread_threads_max == 0)
	{
	  /* The initial thread always exists but the thread library
	     might not yet be initialized.  */
	  th->th_ta_p = (td_thragent_t *) ta;
	  th->th_unique = NULL;

	  return TD_OK;
	}

      return TD_BADTH;
    }

  /* Next test: get the descriptor to see whether this is not an old
     thread handle.  */
  if (ps_pdread (ta->ph, phc.h_descr, &pds,
		 sizeof (struct _pthread_descr_struct)) != PS_OK)
    return TD_ERR;	/* XXX Other error value?  */

  if (pds.p_tid != pt)
    return TD_BADTH;

  if (pds.p_terminated != 0)
    return TD_NOTHR;

  /* Create the `td_thrhandle_t' object.  */
  th->th_ta_p = (td_thragent_t *) ta;
  th->th_unique = phc.h_descr;

  return TD_OK;
}
