mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-10 07:10:06 +00:00
2b778ceb40
I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 6694 files FOO. I then removed trailing white space from benchtests/bench-pthread-locks.c and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this diagnostic from Savannah: remote: *** pre-commit check failed ... remote: *** error: lines with trailing whitespace found remote: error: hook declined to update refs/heads/master
117 lines
4.2 KiB
C
117 lines
4.2 KiB
C
/* Look up a symbol in a single specified object.
|
|
Copyright (C) 1995-2021 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 <ldsodefs.h>
|
|
#include <string.h>
|
|
#include <elf_machine_sym_no_match.h>
|
|
#include <dl-hash.h>
|
|
|
|
/* This function corresponds to do_lookup_x in elf/dl-lookup.c. The
|
|
variant here is simplified because it requires symbol
|
|
versioning. */
|
|
static const ElfW(Sym) *
|
|
check_match (const struct link_map *const map, const char *const undef_name,
|
|
const char *version, uint32_t version_hash,
|
|
const Elf_Symndx symidx)
|
|
{
|
|
const ElfW(Sym) *symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
|
|
const ElfW(Sym) *sym = &symtab[symidx];
|
|
|
|
unsigned int stt = ELFW(ST_TYPE) (sym->st_info);
|
|
if (__glibc_unlikely ((sym->st_value == 0 /* No value. */
|
|
&& sym->st_shndx != SHN_ABS
|
|
&& stt != STT_TLS)
|
|
|| elf_machine_sym_no_match (sym)))
|
|
return NULL;
|
|
|
|
/* Ignore all but STT_NOTYPE, STT_OBJECT, STT_FUNC,
|
|
STT_COMMON, STT_TLS, and STT_GNU_IFUNC since these are no
|
|
code/data definitions. */
|
|
#define ALLOWED_STT \
|
|
((1 << STT_NOTYPE) | (1 << STT_OBJECT) | (1 << STT_FUNC) \
|
|
| (1 << STT_COMMON) | (1 << STT_TLS) | (1 << STT_GNU_IFUNC))
|
|
if (__glibc_unlikely (((1 << stt) & ALLOWED_STT) == 0))
|
|
return NULL;
|
|
|
|
const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
|
|
|
|
if (strcmp (strtab + sym->st_name, undef_name) != 0)
|
|
/* Not the symbol we are looking for. */
|
|
return NULL;
|
|
|
|
ElfW(Half) ndx = map->l_versyms[symidx] & 0x7fff;
|
|
if (map->l_versions[ndx].hash != version_hash
|
|
|| strcmp (map->l_versions[ndx].name, version) != 0)
|
|
/* It's not the version we want. */
|
|
return NULL;
|
|
|
|
return sym;
|
|
}
|
|
|
|
|
|
/* This function corresponds to do_lookup_x in elf/dl-lookup.c. The
|
|
variant here is simplified because it does not search object
|
|
dependencies. It is optimized for a successful lookup. */
|
|
const ElfW(Sym) *
|
|
_dl_lookup_direct (struct link_map *map,
|
|
const char *undef_name, uint32_t new_hash,
|
|
const char *version, uint32_t version_hash)
|
|
{
|
|
const ElfW(Addr) *bitmask = map->l_gnu_bitmask;
|
|
if (__glibc_likely (bitmask != NULL))
|
|
{
|
|
Elf32_Word bucket = map->l_gnu_buckets[new_hash % map->l_nbuckets];
|
|
if (bucket != 0)
|
|
{
|
|
const Elf32_Word *hasharr = &map->l_gnu_chain_zero[bucket];
|
|
|
|
do
|
|
if (((*hasharr ^ new_hash) >> 1) == 0)
|
|
{
|
|
Elf_Symndx symidx = ELF_MACHINE_HASH_SYMIDX (map, hasharr);
|
|
const ElfW(Sym) *sym = check_match (map, undef_name,
|
|
version, version_hash,
|
|
symidx);
|
|
if (sym != NULL)
|
|
return sym;
|
|
}
|
|
while ((*hasharr++ & 1u) == 0);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Fallback code for lack of GNU_HASH support. */
|
|
uint32_t old_hash = _dl_elf_hash (undef_name);
|
|
|
|
/* Use the old SysV-style hash table. Search the appropriate
|
|
hash bucket in this object's symbol table for a definition
|
|
for the same symbol name. */
|
|
for (Elf_Symndx symidx = map->l_buckets[old_hash % map->l_nbuckets];
|
|
symidx != STN_UNDEF;
|
|
symidx = map->l_chain[symidx])
|
|
{
|
|
const ElfW(Sym) *sym = check_match (map, undef_name,
|
|
version, version_hash, symidx);
|
|
if (sym != NULL)
|
|
return sym;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|