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/* ELF symbol resolve functions for VDSO objects.
Copyright (C) 2005-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _DL_VDSO_H
#define _DL_VDSO_H 1
#include <ldsodefs.h>
#include <dl-hash.h>
/* If the architecture support vDSO it should define which is the expected
kernel version and hash value through both VDSO_NAME and VDSO_HASH
(usually defined at architecture sysdep.h). */
#ifndef VDSO_NAME
# define VDSO_NAME "LINUX_0.0"
#endif
#ifndef VDSO_HASH
# define VDSO_HASH 0
#endif
/* Functions for resolving symbols in the VDSO link map. */
static inline void *
dl_vdso_vsym (const char *name)
{
struct link_map *map = GLRO (dl_sysinfo_map);
if (map == NULL)
return NULL;
/* Use a WEAK REF so we don't error out if the symbol is not found. */
ElfW (Sym) wsym = { 0 };
wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
struct r_found_version rfv = { VDSO_NAME, VDSO_HASH, 1, NULL };
/* Search the scope of the vdso map. */
const ElfW (Sym) *ref = &wsym;
lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
map->l_local_scope,
&rfv, 0, 0, NULL);
return ref != NULL ? DL_SYMBOL_ADDRESS (result, ref) : NULL;
}
#endif /* dl-vdso.h */
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