nptl_db/td_thr_tsd.c

   1 /* Get a thread-specific data pointer for a thread.
   2    Copyright (C) 1999-2023 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdint.h>
  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   td_err_e err;
  27   psaddr_t tk_seq, level1, level2, seq, value;
  28   void *copy;
  29   uint32_t pthread_key_2ndlevel_size, idx1st, idx2nd;
  30
  31   LOG ("td_thr_tsd");
  32
  33   /* Get the key entry.  */
  34   err = DB_GET_VALUE (tk_seq, th->th_ta_p, __pthread_keys, tk);
  35   if (err == TD_NOAPLIC)
  36     return TD_BADKEY;
  37   if (err != TD_OK)
  38     return err;
  39
  40   /* Fail if this key is not at all used.  */
  41   if (((uintptr_t) tk_seq & 1) == 0)
  42     return TD_BADKEY;
  43
  44   /* This makes sure we have the size information on hand.  */
  45   err = DB_GET_FIELD_ADDRESS (level2, th->th_ta_p, 0, pthread_key_data_level2,
  46                               data, 1);
  47   if (err != TD_OK)
  48     return err;
  49
  50   /* Compute the indices.  */
  51   pthread_key_2ndlevel_size
  52     = DB_DESC_NELEM (th->th_ta_p->ta_field_pthread_key_data_level2_data);
  53   idx1st = tk / pthread_key_2ndlevel_size;
  54   idx2nd = tk % pthread_key_2ndlevel_size;
  55
  56   /* Now fetch the first level pointer.  */
  57   err = DB_GET_FIELD (level1, th->th_ta_p, th->th_unique, pthread,
  58                       specific, idx1st);
  59   if (err == TD_NOAPLIC)
  60     return TD_DBERR;
  61   if (err != TD_OK)
  62     return err;
  63
  64   /* Check the pointer to the second level array.  */
  65   if (level1 == 0)
  66     return TD_NOTSD;
  67
  68   /* Locate the element within the second level array.  */
  69   err = DB_GET_FIELD_ADDRESS (level2, th->th_ta_p,
  70                               level1, pthread_key_data_level2, data, idx2nd);
  71   if (err == TD_NOAPLIC)
  72     return TD_DBERR;
  73   if (err != TD_OK)
  74     return err;
  75
  76   /* Now copy in that whole structure.  */
  77   err = DB_GET_STRUCT (copy, th->th_ta_p, level2, pthread_key_data);
  78   if (err != TD_OK)
  79     return err;
  80
  81   /* Check whether the data is valid.  */
  82   err = DB_GET_FIELD_LOCAL (seq, th->th_ta_p, copy, pthread_key_data, seq, 0);
  83   if (err != TD_OK)
  84     return err;
  85   if (seq != tk_seq)
  86     return TD_NOTSD;
  87
  88   /* Finally, fetch the value.  */
  89   err = DB_GET_FIELD_LOCAL (value, th->th_ta_p, copy, pthread_key_data,
  90                             data, 0);
  91   if (err == TD_OK)
  92     *data = value;
  93
  94   return err;
  95 }