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/* $OpenBSD: rtld_machine.c,v 1.13 2010/05/03 04:19:42 miod Exp $ */
/*
* Copyright (c) 1998-2004 Opsycon AB, Sweden.
*
* 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 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/mman.h>
#include <link.h>
#include <signal.h>
#include "resolve.h"
#include "syscall.h"
#include "archdep.h"
int
_dl_md_reloc(elf_object_t *object, int rel, int relsz)
{
int i;
int numrel;
int fails = 0;
struct load_list *load_list;
Elf64_Addr loff;
Elf64_Addr ooff;
Elf64_Addr got_start, got_end;
Elf64_Rel *relocs;
const Elf64_Sym *sym, *this;
loff = object->obj_base;
numrel = object->Dyn.info[relsz] / sizeof(Elf64_Rel);
relocs = (Elf64_Rel *)(object->Dyn.info[rel]);
if (relocs == NULL)
return(0);
/*
* Change protection of all write protected segments in the
* object so we can do relocations in the .rodata section.
* After relocation restore protection.
*/
load_list = object->load_list;
while (load_list != NULL) {
if ((load_list->prot & PROT_WRITE) == 0)
_dl_mprotect(load_list->start, load_list->size,
load_list->prot|PROT_WRITE);
load_list = load_list->next;
}
/* XXX We need the got limits to know if reloc is in got. */
/* XXX Relocs against the got should not include the STUB address! */
this = NULL;
got_start = 0;
got_end = 0;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
got_start = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__got_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
got_end = ooff + this->st_value;
DL_DEB(("relocating %d\n", numrel));
for (i = 0; i < numrel; i++, relocs++) {
Elf64_Addr r_addr = relocs->r_offset + loff;
const char *symn;
int type;
if (ELF64_R_SYM(relocs->r_info) == 0xffffff)
continue;
ooff = 0;
sym = object->dyn.symtab;
sym += ELF64_R_SYM(relocs->r_info);
symn = object->dyn.strtab + sym->st_name;
type = ELF64_R_TYPE(relocs->r_info);
this = NULL;
if (ELF64_R_SYM(relocs->r_info) &&
!(ELF64_ST_BIND(sym->st_info) == STB_LOCAL &&
ELF64_ST_TYPE (sym->st_info) == STT_NOTYPE)) {
ooff = _dl_find_symbol(symn, &this,
SYM_SEARCH_ALL | SYM_WARNNOTFOUND | SYM_PLT,
sym, object, NULL);
if (this == NULL) {
if (ELF_ST_BIND(sym->st_info) != STB_WEAK)
fails++;
continue;
}
}
switch (ELF64_R_TYPE(relocs->r_info)) {
/* XXX Handle non aligned relocs. .eh_frame
* XXX in libstdc++ seems to have them... */
u_int64_t robj;
case R_MIPS_REL32_64:
if (ELF64_ST_BIND(sym->st_info) == STB_LOCAL &&
(ELF64_ST_TYPE(sym->st_info) == STT_SECTION ||
ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE) ) {
if ((long)r_addr & 7) {
_dl_bcopy((char *)r_addr, &robj, sizeof(robj));
robj += loff + sym->st_value;
_dl_bcopy(&robj, (char *)r_addr, sizeof(robj));
} else {
*(u_int64_t *)r_addr += loff + sym->st_value;
}
} else if (this && ((long)r_addr & 7)) {
_dl_bcopy((char *)r_addr, &robj, sizeof(robj));
robj += this->st_value + ooff;
_dl_bcopy(&robj, (char *)r_addr, sizeof(robj));
} else if (this) {
*(u_int64_t *)r_addr += this->st_value + ooff;
}
break;
case R_MIPS_NONE:
break;
default:
_dl_printf("%s: unsupported relocation '%d'\n",
_dl_progname, ELF64_R_TYPE(relocs->r_info));
_dl_exit(1);
}
}
DL_DEB(("done %d fails\n", fails));
load_list = object->load_list;
while (load_list != NULL) {
if ((load_list->prot & PROT_WRITE) == 0)
_dl_mprotect(load_list->start, load_list->size,
load_list->prot);
load_list = load_list->next;
}
return(fails);
}
extern void _dl_bind_start(void);
/*
* Relocate the Global Offset Table (GOT). Currently we don't
* do lazy evaluation here because the GNU linker doesn't
* follow the ABI spec which says that if an external symbol
* is referenced by other relocations than CALL16 and 26 it
* should not be given a stub and have a zero value in the
* symbol table. By not doing so, we can't use pointers to
* external functions and use them in comparisons...
*/
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
int i, n;
Elf64_Addr loff;
Elf64_Addr ooff;
Elf64_Addr *gotp;
const Elf64_Sym *symp;
const Elf64_Sym *this;
const char *strt;
if (object->status & STAT_GOT_DONE)
return (0);
loff = object->obj_base;
strt = object->dyn.strtab;
gotp = object->dyn.pltgot;
n = object->Dyn.info[DT_MIPS_LOCAL_GOTNO - DT_LOPROC + DT_NUM];
DL_DEB(("loff: '%p'\n", loff));
/*
* Set up pointers for run time (lazy) resolving.
*/
gotp[0] = (long)_dl_bind_start;
gotp[1] = (long)object;
/* First do all local references. */
for (i = 2; i < n; i++) {
gotp[i] += loff;
}
gotp += n;
symp = object->dyn.symtab;
symp += object->Dyn.info[DT_MIPS_GOTSYM - DT_LOPROC + DT_NUM];
n = object->Dyn.info[DT_MIPS_SYMTABNO - DT_LOPROC + DT_NUM] -
object->Dyn.info[DT_MIPS_GOTSYM - DT_LOPROC + DT_NUM];
this = NULL;
object->plt_size = 0;
object->got_size = 0;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_start = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__got_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_size = ooff + this->st_value - object->got_start;
/*
* Then do all global references according to the ABI.
* Quickstart is not yet implemented.
*/
while (n--) {
if (symp->st_shndx == SHN_UNDEF &&
ELF64_ST_TYPE(symp->st_info) == STT_FUNC) {
if (symp->st_value == 0 || !lazy) {
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name,
&this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
} else
*gotp = symp->st_value + loff;
} else if (symp->st_shndx == SHN_COMMON ||
symp->st_shndx == SHN_UNDEF) {
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name, &this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
} else if (ELF64_ST_TYPE(symp->st_info) == STT_FUNC &&
symp->st_value != *gotp) {
*gotp += loff;
} else { /* Resolve all others immediately */
this = 0;
ooff = _dl_find_symbol(strt + symp->st_name, &this,
SYM_SEARCH_ALL|SYM_NOWARNNOTFOUND|SYM_PLT,
symp, object, NULL);
if (this)
*gotp = this->st_value + ooff;
else
*gotp = symp->st_value + loff;
}
gotp++;
symp++;
}
object->status |= STAT_GOT_DONE;
DL_DEB(("got: %x, %x\n", object->got_start, object->got_size));
if (object->got_size != 0)
_dl_mprotect((void*)object->got_start, object->got_size,
PROT_READ);
return (0);
}
Elf_Addr
_dl_bind(elf_object_t *object, int symidx)
{
Elf_Addr *gotp = object->dyn.pltgot;
Elf_Addr *addr, ooff;
const Elf_Sym *sym, *this;
const char *symn;
sigset_t savedmask;
int n;
sym = object->dyn.symtab;
sym += symidx;
symn = object->dyn.strtab + sym->st_name;
n = object->Dyn.info[DT_MIPS_LOCAL_GOTNO - DT_LOPROC + DT_NUM] -
object->Dyn.info[DT_MIPS_GOTSYM - DT_LOPROC + DT_NUM];
ooff = _dl_find_symbol(symn, &this,
SYM_SEARCH_ALL|SYM_WARNNOTFOUND|SYM_PLT, sym, object, NULL);
if (this == NULL) {
_dl_printf("lazy binding failed\n");
*((int *)0) = 0; /* XXX */
}
addr = &gotp[n + symidx];
/* if GOT is protected, allow the write */
if (object->got_size != 0) {
_dl_thread_bind_lock(0, &savedmask);
_dl_mprotect(addr, sizeof(Elf_Addr), PROT_READ|PROT_WRITE);
}
*addr = ooff + this->st_value;
/* if GOT is (to be protected, change back to RO */
if (object->got_size != 0) {
_dl_mprotect(addr, sizeof (Elf_Addr), PROT_READ);
_dl_thread_bind_lock(1, &savedmask);
}
return *addr;
}
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