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

   1 /* ELF symbol resolve functions for VDSO objects.
   2    Copyright (C) 2005 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 "config.h"
  21 #include <dl-hash.h>
  22 #include <ldsodefs.h>
  23
  24
  25 void *
  26 internal_function
  27 _dl_vdso_vsym (const char *name, const char *version)
  28 {
  29   struct link_map *map = GLRO (dl_sysinfo_map);
  30   void *value = NULL;
  31
  32
  33   if (map != NULL)
  34     {
  35       /* Use a WEAK REF so we don't error out if the symbol is not found.  */
  36       ElfW (Sym) wsym;
  37       memset (&wsym, 0, sizeof (ElfW (Sym)));
  38       wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
  39
  40       /* Compute hash value to the version string.  */
  41       struct r_found_version vers;
  42       vers.name = version;
  43       vers.hidden = 1;
  44       vers.hash = _dl_elf_hash (version);
  45       /* We don't have a specific file where the symbol can be found.  */
  46       vers.filename = NULL;
  47
  48       /* Search the scope of the vdso map.  */
  49       const ElfW (Sym) *ref = &wsym;
  50       lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
  51                                                    map->l_local_scope,
  52                                                    &vers, 0, 0, NULL);
  53
  54       if (ref != NULL)
  55         value = DL_SYMBOL_ADDRESS (result, ref);
  56     }
  57
  58   return value;
  59 }