mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 07:33:38 +08:00
6c03c2cf27
Reject SHN_UNDEF defns iff NOPLT is nonzero. * elf/link.h (_dl_lookup_symbol): Update prototype and comment. * elf/dl-runtime.c (fixup): Pass 1 to _dl_lookup_symbol for NOPLT. * elf/dlsym.c (dlsym): Pass 0. * elf/rtld.c (dl_main): Likewise. * elf/dl-reloc.c (_dl_relocate_object: resolve): Second arg R_OFFSET replaced with NOPLT flag. Pass it through to _dl_lookup_symbol. * elf/do-rel.h (elf_dynamic_do_rel): Update prototype of RESOLVE arg. Pass `elf_machine_pltrel_p (R->r_type)' result as NOPLT flag value. * sysdeps/i386/dl-machine.h (elf_machine_pltrel_p): New macro. * sysdeps/m68k/dl-machine.h (elf_machine_pltrel_p): Likewise. * sysdeps/stub/dl-machine.h (elf_machine_pltrel_p): Likewise.
128 lines
3.7 KiB
C
128 lines
3.7 KiB
C
/* Look up a symbol in the loaded objects.
|
|
Copyright (C) 1995, 1996 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 Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#include <stddef.h>
|
|
#include <libelf.h>
|
|
#include <link.h>
|
|
#include <assert.h>
|
|
|
|
/* Search loaded objects' symbol tables for a definition of the symbol
|
|
UNDEF_NAME. If NOPLT is nonzero, then a PLT entry cannot satisfy the
|
|
reference; some different binding must be found. */
|
|
|
|
Elf32_Addr
|
|
_dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref,
|
|
struct link_map *symbol_scope,
|
|
const char *reference_name,
|
|
int noplt)
|
|
{
|
|
unsigned long int hash = elf_hash (undef_name);
|
|
struct link_map *map;
|
|
struct
|
|
{
|
|
Elf32_Addr a;
|
|
const Elf32_Sym *s;
|
|
} weak_value = { 0, NULL };
|
|
|
|
/* Search the relevant loaded objects for a definition. */
|
|
for (map = symbol_scope; map; map = map->l_next)
|
|
{
|
|
const Elf32_Sym *symtab;
|
|
const char *strtab;
|
|
Elf32_Word symidx;
|
|
|
|
symtab = ((void *) map->l_addr + map->l_info[DT_SYMTAB]->d_un.d_ptr);
|
|
strtab = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr);
|
|
|
|
/* Search the appropriate hash bucket in this object's symbol table
|
|
for a definition for the same symbol name. */
|
|
for (symidx = map->l_buckets[hash % map->l_nbuckets];
|
|
symidx != STN_UNDEF;
|
|
symidx = map->l_chain[symidx])
|
|
{
|
|
const Elf32_Sym *sym = &symtab[symidx];
|
|
|
|
if (sym->st_value == 0 || /* No value. */
|
|
(noplt && sym->st_shndx == SHN_UNDEF)) /* Unwanted PLT entry. */
|
|
continue;
|
|
|
|
switch (ELF32_ST_TYPE (sym->st_info))
|
|
{
|
|
case STT_NOTYPE:
|
|
case STT_FUNC:
|
|
case STT_OBJECT:
|
|
break;
|
|
default:
|
|
/* Not a code/data definition. */
|
|
continue;
|
|
}
|
|
|
|
if (sym != *ref && strcmp (strtab + sym->st_name, undef_name))
|
|
/* Not the symbol we are looking for. */
|
|
continue;
|
|
|
|
switch (ELF32_ST_BIND (sym->st_info))
|
|
{
|
|
case STB_GLOBAL:
|
|
/* Global definition. Just what we need. */
|
|
*ref = sym;
|
|
return map->l_addr;
|
|
case STB_WEAK:
|
|
/* Weak definition. Use this value if we don't find another. */
|
|
if (! weak_value.s)
|
|
{
|
|
weak_value.s = sym;
|
|
weak_value.a = map->l_addr;
|
|
}
|
|
break;
|
|
default:
|
|
/* Local symbols are ignored. */
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (weak_value.s == NULL && ELF32_ST_BIND ((*ref)->st_info) != STB_WEAK)
|
|
{
|
|
const char msg[] = "undefined symbol: ";
|
|
char buf[sizeof msg + strlen (undef_name)];
|
|
memcpy (buf, msg, sizeof msg - 1);
|
|
memcpy (&buf[sizeof msg - 1], undef_name, sizeof buf - sizeof msg + 1);
|
|
_dl_signal_error (0, reference_name, buf);
|
|
}
|
|
|
|
*ref = weak_value.s;
|
|
return weak_value.a;
|
|
}
|
|
|
|
|
|
/* Cache the location of MAP's hash table. */
|
|
|
|
void
|
|
_dl_setup_hash (struct link_map *map)
|
|
{
|
|
Elf32_Word *hash = (void *) map->l_addr + map->l_info[DT_HASH]->d_un.d_ptr;
|
|
Elf32_Word nchain;
|
|
map->l_nbuckets = *hash++;
|
|
nchain = *hash++;
|
|
map->l_buckets = hash;
|
|
hash += map->l_nbuckets;
|
|
map->l_chain = hash;
|
|
}
|