linuxthreads_db/td_thr_tls_get_addr.c

   1 /* Get address of thread local variable.
   2    Copyright (C) 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 2002.
   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
  22 #include "link.h"
  23 #include "thread_dbP.h"
  24
  25 /* Value used for dtv entries for which the allocation is delayed.  */
  26 # define TLS_DTV_UNALLOCATED    ((void *) -1l)
  27
  28
  29 td_err_e
  30 td_thr_tls_get_addr (const td_thrhandle_t *th __attribute__ ((unused)),
  31                      struct link_map *map __attribute__ ((unused)),
  32                      size_t offset __attribute__ ((unused)),
  33                      void **address __attribute__ ((unused)))
  34 {
  35 #if USE_TLS
  36   struct _pthread_descr_struct pds;
  37   size_t modid;
  38   union dtv pdtv;
  39
  40   LOG ("td_thr_tls_get_addr");
  41
  42   /* Get the thread descriptor.  */
  43   if (ps_pdread (th->th_ta_p->ph, th->th_unique, &pds,
  44                  th->th_ta_p->sizeof_descr) != PS_OK)
  45     return TD_ERR;      /* XXX Other error value?  */
  46
  47   /* The module ID.  */
  48   modid = map->l_tls_modid;
  49
  50   /* Get the corresponding entry in the DTV.  */
  51   if (ps_pdread (th->th_ta_p->ph, pds.p_header.data.dtvp + modid, &pdtv,
  52                  sizeof (union dtv)) != PS_OK)
  53     return TD_ERR;      /* XXX Other error value?  */
  54
  55   /* It could be that the memory for this module is not allocated for
  56      the given thread.  */
  57   if (pdtv.pointer == TLS_DTV_UNALLOCATED)
  58     /* There is not much we can do.  */
  59     return TD_NOTALLOC;
  60
  61   *address = (char *) pdtv.pointer + offset;
  62
  63   return TD_OK;
  64 #else
  65   return TD_ERR;
  66 #endif
  67 }