sysdeps/unix/sysv/linux/powerpc/dl-static.c

   1 /* Variable initialization.  PowerPC version.
   2    Copyright (C) 2013-2021 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 <ldsodefs.h>
  20
  21 #ifdef SHARED
  22
  23 void
  24 _dl_var_init (void *array[])
  25 {
  26   /* It has to match "variables" below. */
  27   enum
  28     {
  29       DL_PAGESIZE = 0,
  30       DL_AUXV = 1,
  31       DL_HWCAP = 2,
  32       DL_HWCAP2 = 3,
  33       DL_CACHE_LINE_SIZE = 4
  34     };
  35
  36   GLRO(dl_pagesize) = *((size_t *) array[DL_PAGESIZE]);
  37   GLRO(dl_auxv) = (ElfW(auxv_t) *) *((size_t *) array[DL_AUXV]);
  38   GLRO(dl_hwcap)  = *((unsigned long int *) array[DL_HWCAP]);
  39   GLRO(dl_hwcap2) = *((unsigned long int *) array[DL_HWCAP2]);
  40   GLRO(dl_cache_line_size) = (int) *((int *) array[DL_CACHE_LINE_SIZE]);
  41 }
  42
  43 #else
  44
  45 static void *variables[] =
  46 {
  47   &GLRO(dl_pagesize),
  48   &GLRO(dl_auxv),
  49   &GLRO(dl_hwcap),
  50   &GLRO(dl_hwcap2),
  51   &GLRO(dl_cache_line_size)
  52 };
  53
  54 static void
  55 _dl_unprotect_relro (struct link_map *l)
  56 {
  57   ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
  58                       & ~(GLRO(dl_pagesize) - 1));
  59   ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
  60                     & ~(GLRO(dl_pagesize) - 1));
  61
  62   if (start != end)
  63     __mprotect ((void *) start, end - start, PROT_READ | PROT_WRITE);
  64 }
  65
  66 void
  67 _dl_static_init (struct link_map *l)
  68 {
  69   struct link_map *rtld_map = l;
  70   struct r_scope_elem **scope;
  71   const ElfW(Sym) *ref = NULL;
  72   lookup_t loadbase;
  73   void (*f) (void *[]);
  74   size_t i;
  75
  76   loadbase = _dl_lookup_symbol_x ("_dl_var_init", l, &ref, l->l_local_scope,
  77                                   NULL, 0, 1, NULL);
  78
  79   for (scope = l->l_local_scope; *scope != NULL; scope++)
  80     for (i = 0; i < (*scope)->r_nlist; i++)
  81       if ((*scope)->r_list[i] == loadbase)
  82         {
  83           rtld_map = (*scope)->r_list[i];
  84           break;
  85         }
  86
  87   if (ref != NULL)
  88     {
  89       f = (void (*) (void *[])) DL_SYMBOL_ADDRESS (loadbase, ref);
  90       _dl_unprotect_relro (rtld_map);
  91       f (variables);
  92       _dl_protect_relro (rtld_map);
  93     }
  94 }
  95
  96 #endif