misc/getauxval.c

   1 /* Copyright (C) 2012-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <sys/auxv.h>
  19 #include <errno.h>
  20 #include <ldsodefs.h>
  21 #include <stdbool.h>
  22
  23 bool
  24 __getauxval2 (unsigned long int type, unsigned long int *result)
  25 {
  26 #ifdef HAVE_AUX_VECTOR
  27   ElfW(auxv_t) *p;
  28 #endif
  29
  30   if (type == AT_HWCAP)
  31     {
  32       *result = GLRO(dl_hwcap);
  33       return true;
  34     }
  35   else if (type == AT_HWCAP2)
  36     {
  37       *result = GLRO(dl_hwcap2);
  38       return true;
  39     }
  40
  41 #ifdef HAVE_AUX_VECTOR
  42   for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++)
  43     if (p->a_type == type)
  44       {
  45         *result = p->a_un.a_val;
  46         return true;
  47       }
  48 #endif
  49
  50   return false;
  51 }
  52 libc_hidden_def (__getauxval2)
  53
  54 unsigned long int
  55 __getauxval (unsigned long int type)
  56 {
  57   unsigned long int result;
  58
  59   if (__getauxval2 (type, &result))
  60     return result;
  61
  62   __set_errno (ENOENT);
  63   return 0;
  64 }
  65
  66 weak_alias (__getauxval, getauxval)
  67 libc_hidden_def (__getauxval)