nptl_db/td_thr_tlsbase.c

   1 /* Locate TLS data for a thread.
   2    Copyright (C) 2003, 2006 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include "thread_dbP.h"
  21
  22 td_err_e
  23 td_thr_tlsbase (const td_thrhandle_t *th,
  24                 unsigned long int modid,
  25                 psaddr_t *base)
  26 {
  27   td_err_e err;
  28   psaddr_t dtv, dtvslot, dtvptr;
  29
  30   if (modid < 1)
  31     return TD_NOTLS;
  32
  33   /* Get the DTV pointer from the thread descriptor.  */
  34   err = DB_GET_FIELD (dtv, th->th_ta_p, th->th_unique, pthread, dtvp, 0);
  35   if (err != TD_OK)
  36     return err;
  37
  38   /* Find the corresponding entry in the DTV.  */
  39   err = DB_GET_FIELD_ADDRESS (dtvslot, th->th_ta_p, dtv, dtv, dtv, modid);
  40   if (err != TD_OK)
  41     return err;
  42
  43   /* Extract the TLS block address from that DTV slot.  */
  44   err = DB_GET_FIELD (dtvptr, th->th_ta_p, dtvslot, dtv_t, pointer_val, 0);
  45   if (err != TD_OK)
  46     return err;
  47
  48   /* It could be that the memory for this module is not allocated for
  49      the given thread.  */
  50   if ((uintptr_t) dtvptr & 1)
  51     return TD_TLSDEFER;
  52
  53   *base = dtvptr;
  54   return TD_OK;
  55 }