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

   1 /* Variable initialization.  MIPS version.
   2    Copyright (C) 2001-2019 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     };
  31
  32   GLRO(dl_pagesize) = *((size_t *) array[DL_PAGESIZE]);
  33 }
  34
  35 #else
  36
  37 static void *variables[] =
  38 {
  39   &GLRO(dl_pagesize)
  40 };
  41
  42 static void
  43 _dl_unprotect_relro (struct link_map *l)
  44 {
  45   ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
  46                       & ~(GLRO(dl_pagesize) - 1));
  47   ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
  48                     & ~(GLRO(dl_pagesize) - 1));
  49
  50   if (start != end)
  51     __mprotect ((void *) start, end - start, PROT_READ | PROT_WRITE);
  52 }
  53
  54 void
  55 _dl_static_init (struct link_map *l)
  56 {
  57   struct link_map *rtld_map = l;
  58   struct r_scope_elem **scope;
  59   const ElfW(Sym) *ref = NULL;
  60   lookup_t loadbase;
  61   void (*f) (void *[]);
  62   size_t i;
  63
  64   loadbase = _dl_lookup_symbol_x ("_dl_var_init", l, &ref, l->l_local_scope,
  65                                   NULL, 0, 1, NULL);
  66
  67   for (scope = l->l_local_scope; *scope != NULL; scope++)
  68     for (i = 0; i < (*scope)->r_nlist; i++)
  69       if ((*scope)->r_list[i] == loadbase)
  70         {
  71           rtld_map = (*scope)->r_list[i];
  72           break;
  73         }
  74
  75   if (ref != NULL)
  76     {
  77       f = (void (*) (void *[])) DL_SYMBOL_ADDRESS (loadbase, ref);
  78       _dl_unprotect_relro (rtld_map);
  79       f (variables);
  80       _dl_protect_relro (rtld_map);
  81     }
  82 }
  83
  84 #endif