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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include "thread_dbP.h"
  22 #include <linuxthreads/internals.h>
  23
  24
  25 td_err_e
  26 td_thr_tsd (const td_thrhandle_t *th, const thread_key_t tk, void **data)
  27 {
  28   struct _pthread_descr_struct pds;
  29   struct pthread_key_struct *keys = th->th_ta_p->keys;
  30   struct pthread_key_struct key;
  31   int pthread_keys_max = th->th_ta_p->pthread_keys_max;
  32   int pthread_key_2ndlevel_size = th->th_ta_p->pthread_key_2ndlevel_size;
  33   unsigned int idx1st;
  34   unsigned int idx2nd;
  35   void *p;
  36
  37   LOG ("td_thr_tsd");
  38
  39   /* If there is no thread descriptor there cannot be any thread
  40      specific data.  */
  41   if (th->th_unique == NULL)
  42     return TD_BADKEY;
  43
  44   /* Get the thread descriptor.  */
  45   if (ps_pdread (th->th_ta_p->ph, th->th_unique, &pds,
  46                  sizeof (struct _pthread_descr_struct)) != PS_OK)
  47     return TD_ERR;      /* XXX Other error value?  */
  48
  49   /* Check correct value of key.  */
  50   if (tk >= pthread_keys_max)
  51     return TD_BADKEY;
  52
  53   /* Get the key entry.  */
  54   if (ps_pdread (th->th_ta_p->ph, &keys[tk], &key,
  55                  sizeof (struct pthread_key_struct)) != PS_OK)
  56     return TD_ERR;      /* XXX Other error value?  */
  57
  58   /* Fail if this key is not at all used.  */
  59   if (! key.in_use)
  60     return TD_BADKEY;
  61
  62   /* Compute the indeces.  */
  63   idx1st = tk / pthread_key_2ndlevel_size;
  64   idx2nd = tk % pthread_key_2ndlevel_size;
  65
  66   /* Check the pointer to the second level array.  */
  67   if (pds.p_specific[idx1st] == NULL)
  68     return TD_NOTSD;
  69
  70   /* Now get the real key.
  71      XXX I don't know whether it's correct but there is currently no
  72      easy way to determine whether a key was never set or the value
  73      is NULL.  We return an error whenever the value is NULL.  */
  74   if (ps_pdread (th->th_ta_p->ph, &pds.p_specific[idx1st][idx2nd], &p,
  75                  sizeof (void *)) != PS_OK)
  76     return TD_ERR;
  77
  78   if (p != NULL)
  79     *data = p;
  80
  81   return p != NULL ? TD_OK : TD_NOTSD;
  82 }