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/* $NetBSD: mdreloc.c,v 1.2 2015/03/27 23:14:53 matt Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mdreloc.c,v 1.2 2015/03/27 23:14:53 matt Exp $");
#endif /* not lint */
#include <sys/types.h>
#include <sys/endian.h>
#include <sys/tls.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "rtld.h"
void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
void *_rtld_bind(const Obj_Entry *, Elf_Word);
void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
obj->pltgot[1] = (Elf_Addr) obj;
}
void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rela *rela = NULL, *relalim;
Elf_Addr relasz = 0;
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 *)((uintptr_t)rela + relasz);
for (; rela < relalim; rela++) {
Elf_Word r_type = ELF_R_TYPE(rela->r_info);
Elf_Addr *where = (Elf_Addr *)(relocbase + rela->r_offset);
switch (r_type) {
case R_TYPE(RELATIVE): {
Elf_Addr val = relocbase + rela->r_addend;
*where = val;
rdbg(("RELATIVE/L(%p) -> %p in <self>",
where, (void *)val));
break;
}
case R_TYPE(NONE):
break;
default:
abort();
}
}
}
int
_rtld_relocate_nonplt_objects(Obj_Entry *obj)
{
const Elf_Rela *rela;
const Elf_Sym *def;
const Obj_Entry *defobj;
for (rela = obj->rela; rela < obj->relalim; rela++) {
Elf_Addr * const where =
(Elf_Addr *)(obj->relocbase + rela->r_offset);
const Elf_Word r_symndx = ELF_R_SYM(rela->r_info);
const Elf_Word r_type = ELF_R_TYPE(rela->r_info);
switch (r_type) {
case R_TYPE(NONE):
break;
case R_TYPE(RELATIVE): {
def = obj->symtab + r_symndx;
Elf_Addr val = (Elf_Addr)obj->relocbase + rela->r_addend;
rdbg(("RELATIVE(%p) -> %p (%s) in %s",
where, (void *)val,
obj->strtab + def->st_name, obj->path));
*where = val;
break;
}
case R_TYPESZ(ADDR): {
def = _rtld_find_symdef(r_symndx, obj, &defobj, false);
if (def == NULL)
return -1;
Elf_Addr val = (Elf_Addr)defobj->relocbase + rela->r_addend;
*where = val;
rdbg(("ADDR %s in %s --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void *)val, defobj->path));
break;
}
case R_TYPESZ(TLS_DTPMOD): {
def = _rtld_find_symdef(r_symndx, obj, &defobj, false);
if (def == NULL)
return -1;
Elf_Addr val = (Elf_Addr)defobj->tlsindex + rela->r_addend;
*where = val;
rdbg(("DTPMOD %s in %s --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void *)val, defobj->path));
break;
}
case R_TYPESZ(TLS_DTPREL): {
Elf_Addr old = *where;
Elf_Addr val = old;
def = _rtld_find_symdef(r_symndx, obj, &defobj, false);
if (def == NULL)
return -1;
if (!defobj->tls_done && _rtld_tls_offset_allocate(obj))
return -1;
val = (Elf_Addr)def->st_value - TLS_DTV_OFFSET;
*where = val;
rdbg(("DTPREL %s in %s --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void *)val, defobj->path));
break;
}
default:
rdbg(("sym = %lu, type = %lu, offset = %p, "
"addend = %p, contents = %p, symbol = %s",
(u_long)r_symndx, (u_long)r_type,
(void *)rela->r_offset, (void *)rela->r_addend,
(void *)load_ptr(where, sizeof(Elf_Addr)),
obj->strtab + obj->symtab[r_symndx].st_name));
_rtld_error("%s: Unsupported relocation type %ld "
"in non-PLT relocations",
obj->path, (u_long)r_type);
return -1;
}
}
return 0;
}
int
_rtld_relocate_plt_lazy(const Obj_Entry *obj)
{
/* PLT fixups were done above in the GOT relocation. */
return 0;
}
static int
_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rel *rel,
Elf_Addr *tp)
{
const Obj_Entry *defobj;
Elf_Addr new_value;
assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT));
const Elf_Sym *def = _rtld_find_plt_symdef(ELF_R_SYM(rel->r_info),
obj, &defobj, tp != NULL);
if (__predict_false(def == NULL))
return -1;
if (__predict_false(def == &_rtld_sym_zero))
return -1;
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);
}
rdbg(("bind now/fixup in %s --> new=%p",
defobj->strtab + def->st_name, (void *)new_value));
*(Elf_Addr *)(obj->relocbase + rel->r_offset) = new_value;
if (tp)
*tp = new_value;
return 0;
}
void *
_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
{
const Elf_Rel *pltrel = (const Elf_Rel *)(obj->pltrel + reloff);
Elf_Addr new_value;
int err;
_rtld_shared_enter();
err = _rtld_relocate_plt_object(obj, pltrel, &new_value);
if (err)
_rtld_die();
_rtld_shared_exit();
return (caddr_t)new_value;
}
int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
for (const Elf_Rel *rel = obj->pltrel; rel < obj->pltrellim; rel++) {
if (_rtld_relocate_plt_object(obj, rel, NULL) < 0)
return -1;
}
return 0;
}
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