libpthread/linuxthreads_db/td_thr_tsd.c

   1 /* Get a thread-specific data pointer for a thread.
   2    Copyright (C) 1999, 2001, 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include "thread_dbP.h"
  21
  22
  23 td_err_e
  24 td_thr_tsd (const td_thrhandle_t *th, const thread_key_t tk, void **data)
  25 {
  26   struct _pthread_descr_struct pds;
  27   struct pthread_key_struct *keys = th->th_ta_p->keys;
  28   struct pthread_key_struct key;
  29   int pthread_keys_max = th->th_ta_p->pthread_keys_max;
  30   int pthread_key_2ndlevel_size = th->th_ta_p->pthread_key_2ndlevel_size;
  31   unsigned int idx1st;
  32   unsigned int idx2nd;
  33   void *p;
  34
  35   LOG ("td_thr_tsd");
  36
  37   /* If there is no thread descriptor there cannot be any thread
  38      specific data.  */
  39   if (th->th_unique == NULL)
  40     return TD_BADKEY;
  41
  42   /* Get the thread descriptor.  */
  43   if (ps_pdread (th->th_ta_p->ph, th->th_unique, &pds,
  44                  sizeof (struct _pthread_descr_struct)) != PS_OK)
  45     return TD_ERR;      /* XXX Other error value?  */
  46
  47   /* Check correct value of key.  */
  48   if (tk >= pthread_keys_max)
  49     return TD_BADKEY;
  50
  51   /* Get the key entry.  */
  52   if (ps_pdread (th->th_ta_p->ph, &keys[tk], &key,
  53                  sizeof (struct pthread_key_struct)) != PS_OK)
  54     return TD_ERR;      /* XXX Other error value?  */
  55
  56   /* Fail if this key is not at all used.  */
  57   if (! key.in_use)
  58     return TD_BADKEY;
  59
  60   /* Compute the indeces.  */
  61   idx1st = tk / pthread_key_2ndlevel_size;
  62   idx2nd = tk % pthread_key_2ndlevel_size;
  63
  64   /* Check the pointer to the second level array.  */
  65   if (pds.p_specific[idx1st] == NULL)
  66     return TD_NOTSD;
  67
  68   /* Now get the real key.
  69      XXX I don't know whether it's correct but there is currently no
  70      easy way to determine whether a key was never set or the value
  71      is NULL.  We return an error whenever the value is NULL.  */
  72   if (ps_pdread (th->th_ta_p->ph, &pds.p_specific[idx1st][idx2nd], &p,
  73                  sizeof (void *)) != PS_OK)
  74     return TD_ERR;
  75
  76   if (p != NULL)
  77     *data = p;
  78
  79   return p != NULL ? TD_OK : TD_NOTSD;
  80 }