glibc/elf/dl-setup_hash.c

64 lines
2.0 KiB
C

/* Cache the location of a link map hash table.
Copyright (C) 1995-2022 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/>. */
#include <assert.h>
#include <link.h>
#include <ldsodefs.h>
void
_dl_setup_hash (struct link_map *map)
{
Elf_Symndx *hash;
if (__glibc_likely (map->l_info[ELF_MACHINE_GNU_HASH_ADDRIDX] != NULL))
{
Elf32_Word *hash32
= (void *) D_PTR (map, l_info[ELF_MACHINE_GNU_HASH_ADDRIDX]);
map->l_nbuckets = *hash32++;
Elf32_Word symbias = *hash32++;
Elf32_Word bitmask_nwords = *hash32++;
/* Must be a power of two. */
assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
map->l_gnu_shift = *hash32++;
map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
map->l_gnu_buckets = hash32;
hash32 += map->l_nbuckets;
map->l_gnu_chain_zero = hash32 - symbias;
/* Initialize MIPS xhash translation table. */
ELF_MACHINE_XHASH_SETUP (hash32, symbias, map);
return;
}
if (!map->l_info[DT_HASH])
return;
hash = (void *) D_PTR (map, l_info[DT_HASH]);
map->l_nbuckets = *hash++;
/* Skip nchain. */
hash++;
map->l_buckets = hash;
hash += map->l_nbuckets;
map->l_chain = hash;
}