1/* ELF symbol resolve functions for VDSO objects.
2 Copyright (C) 2005-2017 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 <http://www.gnu.org/licenses/>. */
18
19#include "config.h"
20#include <ldsodefs.h>
21
22
23void *
24internal_function
25_dl_vdso_vsym (const char *name, const struct r_found_version *vers)
26{
27 struct link_map *map = GLRO (dl_sysinfo_map);
28 void *value = NULL;
29
30
31 if (map != NULL)
32 {
33 /* Use a WEAK REF so we don't error out if the symbol is not found. */
34 ElfW (Sym) wsym;
35 memset (&wsym, 0, sizeof (ElfW (Sym)));
36 wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
37
38 /* Search the scope of the vdso map. */
39 const ElfW (Sym) *ref = &wsym;
40 lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
41 map->l_local_scope,
42 vers, 0, 0, NULL);
43
44 if (ref != NULL)
45 value = DL_SYMBOL_ADDRESS (result, ref);
46 }
47
48 return value;
49}
50