1 /* ELF symbol resolve functions for VDSO objects.
2 Copyright (C) 2005-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
25 /* If the architecture support vDSO it should define which is the expected
26 kernel version and hash value through both VDSO_NAME and VDSO_HASH
27 (usually defined at architecture sysdep.h). */
30 # define VDSO_NAME "LINUX_0.0"
36 /* Functions for resolving symbols in the VDSO link map. */
38 dl_vdso_vsym (const char *name
)
40 struct link_map
*map
= GLRO (dl_sysinfo_map
);
44 /* Use a WEAK REF so we don't error out if the symbol is not found. */
45 ElfW (Sym
) wsym
= { 0 };
46 wsym
.st_info
= (unsigned char) ELFW (ST_INFO (STB_WEAK
, STT_NOTYPE
));
48 const struct r_found_version rfv
= { VDSO_NAME
, VDSO_HASH
, 1, NULL
};
50 /* Search the scope of the vdso map. */
51 const ElfW (Sym
) *ref
= &wsym
;
52 lookup_t result
= GLRO (dl_lookup_symbol_x
) (name
, map
, &ref
,
55 return ref
!= NULL
? DL_SYMBOL_ADDRESS (result
, ref
) : NULL
;
58 #endif /* dl-vdso.h */