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/* $NetBSD: mdreloc.c,v 1.30 2014/08/25 20:40:53 joerg Exp $ */
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mdreloc.c,v 1.30 2014/08/25 20:40:53 joerg Exp $");
#endif /* not lint */
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mdreloc.c,v 1.30 2014/08/25 20:40:53 joerg Exp $");
#endif /* not lint */
#include <sys/types.h>
#include "debug.h"
#include "rtld.h"
void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
static inline int _rtld_relocate_plt_object(const Obj_Entry *,
const Elf_Rela *, Elf_Addr *);
void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
obj->pltgot[1] = (Elf_Addr) obj;
obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
}
void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rela *rela = 0, *relalim;
Elf_Addr relasz = 0;
Elf_Addr *where;
for (; dynp->d_tag != DT_NULL; dynp++) {
switch (dynp->d_tag) {
case DT_RELA:
rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
break;
case DT_RELASZ:
relasz = dynp->d_un.d_val;
break;
}
}
relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz);
for (; rela < relalim; rela++) {
where = (Elf_Addr *)(relocbase + rela->r_offset);
*where = (Elf_Addr)(relocbase + rela->r_addend);
}
}
int
_rtld_relocate_nonplt_objects(Obj_Entry *obj)
{
const Elf_Rela *rela;
for (rela = obj->rela; rela < obj->relalim; rela++) {
Elf_Addr *where;
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr tmp;
unsigned long symnum;
where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
symnum = ELF_R_SYM(rela->r_info);
switch (ELF_R_TYPE(rela->r_info)) {
case R_TYPE(NONE):
break;
case R_TYPE(32): /* word32 S + A */
case R_TYPE(GLOB_DAT): /* word32 S + A */
def = _rtld_find_symdef(symnum, obj, &defobj, false);
if (def == NULL)
return -1;
tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
rela->r_addend);
if (*where != tmp)
*where = tmp;
rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
obj->strtab + obj->symtab[symnum].st_name,
obj->path, (void *)*where, defobj->path));
break;
case R_TYPE(RELATIVE): /* word32 B + A */
tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
if (*where != tmp)
*where = tmp;
rdbg(("RELATIVE in %s --> %p", obj->path,
(void *)*where));
break;
case R_TYPE(COPY):
/*
* These are deferred until all other relocations have
* been done. All we do here is make sure that the
* COPY relocation is not in a shared library. They
* are allowed only in executable files.
*/
if (obj->isdynamic) {
_rtld_error(
"%s: Unexpected R_COPY relocation in shared library",
obj->path);
return -1;
}
rdbg(("COPY (avoid in main)"));
break;
default:
rdbg(("sym = %lu, type = %lu, offset = %p, "
"addend = %p, contents = %p, symbol = %s",
symnum, (u_long)ELF_R_TYPE(rela->r_info),
(void *)rela->r_offset, (void *)rela->r_addend,
(void *)*where,
obj->strtab + obj->symtab[symnum].st_name));
_rtld_error("%s: Unsupported relocation type %ld "
"in non-PLT relocations",
obj->path, (u_long) ELF_R_TYPE(rela->r_info));
return -1;
}
}
return 0;
}
int
_rtld_relocate_plt_lazy(const Obj_Entry *obj)
{
const Elf_Rela *rela;
if (!obj->relocbase)
return 0;
for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
/* Just relocate the GOT slots pointing into the PLT */
*where += (Elf_Addr)obj->relocbase;
rdbg(("lazy fixup pltgot %p in %s --> %p", where, obj->path,
(void *)*where));
}
return 0;
}
static inline int
_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp)
{
Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
Elf_Addr new_value;
const Elf_Sym *def;
const Obj_Entry *defobj;
unsigned long info = rela->r_info;
assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT));
def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
if (__predict_false(def == NULL))
return -1;
if (__predict_false(def == &_rtld_sym_zero))
return 0;
if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
if (tp == NULL)
return 0;
new_value = _rtld_resolve_ifunc(defobj, def);
} else {
new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
rela->r_addend);
}
rdbg(("bind now/fixup pltgot %p in %s --> old=%p new=%p", where,
defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
if (*where != new_value)
*where = new_value;
if (tp)
*tp = new_value - rela->r_addend;
return 0;
}
caddr_t
_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
{
const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff);
Elf_Addr result;
int err;
result = 0; /* XXX gcc */
_rtld_shared_enter();
err = _rtld_relocate_plt_object(obj, rela, &result);
if (err)
_rtld_die();
_rtld_shared_exit();
return (caddr_t)result;
}
int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
const Elf_Rela *rela;
for (rela = obj->pltrela; rela < obj->pltrelalim; rela++)
if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
return -1;
return 0;
}
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