1 | /* ELF symbol resolve functions for VDSO objects. |
2 | Copyright (C) 2005-2019 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 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include "config.h" |
20 | #include <ldsodefs.h> |
21 | |
22 | |
23 | void * |
24 | _dl_vdso_vsym (const char *name, const struct r_found_version *vers) |
25 | { |
26 | struct link_map *map = GLRO (dl_sysinfo_map); |
27 | void *value = NULL; |
28 | |
29 | |
30 | if (map != NULL) |
31 | { |
32 | /* Use a WEAK REF so we don't error out if the symbol is not found. */ |
33 | ElfW (Sym) wsym; |
34 | memset (&wsym, 0, sizeof (ElfW (Sym))); |
35 | wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE)); |
36 | |
37 | /* Search the scope of the vdso map. */ |
38 | const ElfW (Sym) *ref = &wsym; |
39 | lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref, |
40 | map->l_local_scope, |
41 | vers, 0, 0, NULL); |
42 | |
43 | if (ref != NULL) |
44 | value = DL_SYMBOL_ADDRESS (result, ref); |
45 | } |
46 | |
47 | return value; |
48 | } |
49 | |