nptl_db/td_thr_tlsbase.c

   1 /* Locate TLS data for a thread.
   2    Copyright (C) 2003 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 /* Value used for dtv entries for which the allocation is delayed.  */
  23 # define TLS_DTV_UNALLOCATED    ((void *) -1l)
  24
  25 td_err_e
  26 td_thr_tlsbase (const td_thrhandle_t *th,
  27                 unsigned long int modid,
  28                 psaddr_t *base)
  29 {
  30   if (modid < 1)
  31     return TD_NOTLS;
  32
  33 #if USE_TLS
  34   union dtv pdtv, *dtvp;
  35
  36   LOG ("td_thr_tlsbase");
  37
  38   psaddr_t dtvpp = th->th_unique;
  39 #if TLS_TCB_AT_TP
  40   dtvpp += offsetof (struct pthread, header.dtv);
  41 #elif TLS_DTV_AT_TP
  42   dtvpp += TLS_PRE_TCB_SIZE + offsetof (tcbhead_t, dtv);
  43 #else
  44 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined."
  45 #endif
  46
  47   /* Get the DTV pointer from the thread descriptor.  */
  48   if (ps_pdread (th->th_ta_p->ph, dtvpp, &dtvp, sizeof dtvp) != PS_OK)
  49     return TD_ERR;      /* XXX Other error value?  */
  50
  51   /* Get the corresponding entry in the DTV.  */
  52   if (ps_pdread (th->th_ta_p->ph, dtvp + modid,
  53                  &pdtv, sizeof (union dtv)) != PS_OK)
  54     return TD_ERR;      /* XXX Other error value?  */
  55
  56   /* It could be that the memory for this module is not allocated for
  57      the given thread.  */
  58   if (pdtv.pointer == TLS_DTV_UNALLOCATED)
  59     return TD_TLSDEFER;
  60
  61   *base = (char *) pdtv.pointer;
  62
  63   return TD_OK;
  64 #else
  65   return TD_ERR;
  66 #endif
  67 }