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/* $OpenBSD: rtld_machine.c,v 1.10 2002/05/24 04:17:00 deraadt Exp $ */
/*
* Copyright (c) 1999 Dale Rahn
* Copyright (c) 2001 Niklas Hallqvist
* Copyright (c) 2001 Artur Grabowski
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed under OpenBSD by
* Dale Rahn.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
*/
#define _DYN_LOADER
#include <sys/types.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <machine/elf_machdep.h>
#include <nlist.h>
#include <link.h>
#include "syscall.h"
#include "archdep.h"
#include "resolve.h"
void
_dl_bcopy(void *src, void *dest, int size)
{
unsigned char *psrc, *pdest;
int i;
psrc = src;
pdest = dest;
for (i = 0; i < size; i++) {
pdest[i] = psrc[i];
}
}
int
_dl_md_reloc(elf_object_t *object, int rel, int relasz)
{
long i;
long numrela;
long fails = 0;
Elf64_Addr loff;
Elf64_Rela *relas;
load_list_t *llist;
loff = object->load_offs;
numrela = object->Dyn.info[relasz] / sizeof(Elf64_Rela);
relas = (Elf64_Rela *)(object->Dyn.info[rel]);
if ((object->status & STAT_RELOC_DONE) || !relas)
return(0);
/*
* unprotect some segments if we need it.
* XXX - we unprotect waay to much. only the text can have cow
* relocations.
*/
if ((rel == DT_REL || rel == DT_RELA)) {
for (llist = object->load_list; llist != NULL; llist = llist->next) {
if (!(llist->prot & PROT_WRITE)) {
_dl_mprotect(llist->start, llist->size,
llist->prot|PROT_WRITE);
}
}
}
for (i = 0; i < numrela; i++, relas++) {
Elf64_Addr *r_addr;
Elf64_Addr ooff;
const Elf64_Sym *sym, *this;
const char *symn;
r_addr = (Elf64_Addr *)(relas->r_offset + loff);
if (ELF64_R_SYM(relas->r_info) == 0xffffffff)
continue;
sym = object->dyn.symtab;
sym += ELF64_R_SYM(relas->r_info);
symn = object->dyn.strtab + sym->st_name;
this = NULL;
switch (ELF64_R_TYPE(relas->r_info)) {
case R_TYPE(REFQUAD):
ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1);
if (this == NULL)
goto resolve_failed;
*r_addr += ooff + this->st_value + relas->r_addend;
break;
case R_TYPE(RELATIVE):
/*
* There is a lot of unaligned RELATIVE
* relocs generated by gcc in the exception handlers.
*/
if ((((Elf_Addr) r_addr) & 0x7) != 0) {
Elf_Addr tmp;
#if 0
_dl_printf("unaligned RELATIVE: %p type: %d %s 0x%lx -> 0x%lx\n", r_addr,
ELF_R_TYPE(relas->r_info), object->load_name, *r_addr, *r_addr+loff);
#endif
_dl_bcopy(r_addr, &tmp, sizeof(Elf_Addr));
tmp += loff;
_dl_bcopy(&tmp, r_addr, sizeof(Elf_Addr));
} else
*r_addr += loff;
break;
case R_TYPE(JMP_SLOT):
ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1);
if (this == NULL)
goto resolve_failed;
*r_addr = ooff + this->st_value + relas->r_addend;
break;
case R_TYPE(GLOB_DAT):
ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1);
if (this == NULL)
goto resolve_failed;
*r_addr = ooff + this->st_value + relas->r_addend;
break;
case R_TYPE(NONE):
break;
default:
_dl_printf("%s:"
" %s: unsupported relocation '%s' %d at %lx\n",
_dl_progname, object->load_name, symn,
ELF64_R_TYPE(relas->r_info), r_addr );
_dl_exit(1);
}
continue;
resolve_failed:
_dl_printf("%s: %s :can't resolve reference '%s'\n",
_dl_progname, object->load_name, symn);
fails++;
}
__asm __volatile("imb" : : : "memory");
/* reprotect the unprotected segments */
if ((rel == DT_REL || rel == DT_RELA)) {
for (llist = object->load_list; llist != NULL; llist = llist->next) {
if (!(llist->prot & PROT_WRITE))
_dl_mprotect(llist->start, llist->size,
llist->prot);
}
}
return (fails);
}
/*
* Resolve a symbol at run-time.
*/
void *
_dl_bind(elf_object_t *object, Elf_Word reloff)
{
Elf_RelA *rela;
Elf_Addr *addr, ooff;
const Elf_Sym *sym, *this;
const char *symn;
rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL] + reloff);
sym = object->dyn.symtab;
sym += ELF64_R_SYM(rela->r_info);
symn = object->dyn.strtab + sym->st_name;
addr = (Elf_Addr *)(object->load_offs + rela->r_offset);
ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1);
if (this == NULL) {
_dl_printf("lazy binding failed!\n");
*((int *)0) = 0; /* XXX */
}
*addr = ooff + this->st_value + rela->r_addend;
return (void *)*addr;
}
/*
* Relocate the Global Offset Table (GOT).
*/
void
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
Elf_Addr *pltgot;
extern void _dl_bind_start(void); /* XXX */
pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
if (object->obj_type == OBJTYPE_LDR || !lazy || pltgot == NULL) {
_dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
return;
}
if (object->obj_type != OBJTYPE_EXE) {
int i, size;
Elf_Addr *addr;
Elf_RelA *rela;
size = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf_RelA);
rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL]);
for (i = 0; i < size; i++) {
addr = (Elf_Addr *)(object->load_offs + rela[i].r_offset);
*addr += object->load_offs;
}
}
pltgot[2] = (Elf_Addr)_dl_bind_start;
pltgot[3] = (Elf_Addr)object;
}
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