int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
extern void _dl_bind_start(void); /* XXX */
int fails = 0;
Elf_Addr *pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
int i, num;
Elf_RelA *rel;
if (pltgot == NULL)
return (0); /* it is possible to have no PLT/GOT relocations */
if (object->Dyn.info[DT_PLTREL] != DT_RELA)
return (0);
if (object->traced)
lazy = 1;
if (__predict_false(!lazy)) {
fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
} else {
pltgot[1] = (Elf_Addr)object;
pltgot[2] = (Elf_Addr)&_dl_bind_start;
rel = (Elf_RelA *)(object->Dyn.info[DT_JMPREL]);
num = (object->Dyn.info[DT_PLTRELSZ]);
for (i = 0; i < num/sizeof(Elf_RelA); i++, rel++) {
Elf_Addr *where;
where = (Elf_Addr *)(rel->r_offset + object->obj_base);
*where += object->obj_base;
}
}
/* mprotect the GOT */
_dl_protect_segment(object, 0, "__got_start", "__got_end", PROT_READ);
return (fails);
}
/*
* Relocate the Global Offset Table (GOT).
*/
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
int fails = 0;
Elf_Addr *pltgot;
extern void _dl_bind_start(void); /* XXX */
Elf_Addr ooff;
Elf_Addr plt_addr;
const Elf_Sym *this;
pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
object->got_addr = 0;
object->got_size = 0;
this = NULL;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_addr = 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_addr;
plt_addr = 0;
object->plt_size = 0;
this = NULL;
ooff = _dl_find_symbol("__plt_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
plt_addr = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__plt_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->plt_size = ooff + this->st_value - plt_addr;
if (object->got_addr == 0)
object->got_start = 0;
else {
object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz);
object->got_size += object->got_addr - object->got_start;
object->got_size = ELF_ROUND(object->got_size, _dl_pagesz);
}
if (plt_addr == 0)
object->plt_start = 0;
else {
object->plt_start = ELF_TRUNC(plt_addr, _dl_pagesz);
object->plt_size += plt_addr - object->plt_start;
object->plt_size = ELF_ROUND(object->plt_size, _dl_pagesz);
}
if (object->obj_type == OBJTYPE_LDR || !lazy || pltgot == NULL) {
fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
} else {
if (object->obj_base != 0) {
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->obj_base +
rela[i].r_offset);
*addr += object->obj_base;
}
}
}
if (pltgot != NULL) {
pltgot[2] = (Elf_Addr)_dl_bind_start;
pltgot[3] = (Elf_Addr)object;
}
if (object->got_size != 0)
_dl_mprotect((void*)object->got_start, object->got_size,
PROT_READ);
if (object->plt_size != 0)
_dl_mprotect((void*)object->plt_start, object->plt_size,
PROT_READ|PROT_EXEC);
return (fails);
}
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
Elf_RelA *rela;
Elf_Addr ooff;
int i, numrela, fails = 0;
const Elf_Sym *this;
if (object->dyn.pltrel != DT_RELA)
return (0);
object->got_addr = 0;
object->got_size = 0;
this = NULL;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL );
if (this != NULL)
object->got_addr = 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_addr;
if (object->got_addr == 0)
object->got_start = 0;
else {
object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz);
object->got_size += object->got_addr - object->got_start;
object->got_size = ELF_ROUND(object->got_size, _dl_pagesz);
}
if (object->traced)
lazy = 1;
if (!lazy) {
fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
} else {
register Elf_Addr ltp __asm ("%r19");
Elf_Addr *got = NULL;
rela = (Elf_RelA *)(object->dyn.jmprel);
numrela = object->dyn.pltrelsz / sizeof(Elf_RelA);
ooff = object->obj_base;
/*
* Find the PLT stub by looking at all the
* relocations. The PLT stub should be at the end of
* the .plt section so we start with the last
* relocation, since the linker should have emitted
* them in order.
*/
for (i = numrela - 1; i >= 0; i--) {
got = (Elf_Addr *)(ooff + rela[i].r_offset +
PLT_ENTRY_SIZE + PLT_STUB_SIZE);
if (got[-2] == PLT_STUB_MAGIC1 ||
got[-1] == PLT_STUB_MAGIC2)
break;
got = NULL;
}
if (got == NULL)
return (1);
/*
* Patch up the PLT stub such that it doesn't clobber
* %r22, which is used to pass on the errno values
* from failed system calls to __cerrno() in libc.
*/
got[-7] = PLT_STUB_INSN1;
got[-6] = PLT_STUB_INSN2;
__asm volatile("fdc 0(%0)" :: "r" (&got[-7]));
__asm volatile("fdc 0(%0)" :: "r" (&got[-6]));
__asm volatile("sync");
__asm volatile("fic 0(%%sr0,%0)" :: "r" (&got[-7]));
__asm volatile("fic 0(%%sr0,%0)" :: "r" (&got[-6]));
__asm volatile("sync");
/*
* Fill in the PLT stub such that it invokes the
* _dl_bind_start() trampoline to fix up the
* relocation.
*/
got[1] = (Elf_Addr)object;
got[-2] = (Elf_Addr)&_dl_bind_start;
got[-1] = ltp;
/*
* Even though we didn't modify any instructions it
* seems we still need to syncronize the caches.
* There may be instructions in the same cache line
* and they end up being corrupted otherwise.
*/
__asm volatile("fdc 0(%0)" :: "r" (&got[-2]));
__asm volatile("fdc 0(%0)" :: "r" (&got[-1]));
__asm volatile("sync");
__asm volatile("fic 0(%%sr0,%0)" :: "r" (&got[-2]));
__asm volatile("fic 0(%%sr0,%0)" :: "r" (&got[-1]));
__asm volatile("sync");
for (i = 0; i < numrela; i++, rela++) {
Elf_Addr *r_addr = (Elf_Addr *)(ooff + rela->r_offset);
if (ELF_R_TYPE(rela->r_info) != RELOC_IPLT) {
_dl_printf("unexpected reloc 0x%x\n",
ELF_R_TYPE(rela->r_info));
return (1);
}
if (ELF_R_SYM(rela->r_info)) {
r_addr[0] = (Elf_Addr)got - PLT_STUB_GOTOFF;
r_addr[1] = (Elf_Addr) (rela -
(Elf_RelA *)object->dyn.jmprel);
} else {
r_addr[0] = ooff + rela->r_addend;
r_addr[1] = (Elf_Addr)object->dyn.pltgot;
}
}
}
if (object->got_size != 0)
_dl_mprotect((void *)object->got_start, object->got_size,
GOT_PERMS|PROT_EXEC);
return (fails);
}
/*
* Relocate the Global Offset Table (GOT).
* This is done by calling _dl_md_reloc on DT_JMPREL for DL_BIND_NOW,
* otherwise the lazy binding plt initialization is performed.
*/
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
extern void _dl_bind_start(void); /* XXX */
int fails = 0;
Elf_Addr *pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
Elf_Addr ooff;
const Elf_Sym *this;
if (pltgot == NULL)
return (0);
pltgot[1] = (Elf_Addr)object;
pltgot[2] = (Elf_Addr)_dl_bind_start;
if (object->Dyn.info[DT_PLTREL] != DT_RELA)
return (0);
object->got_addr = 0;
object->got_size = 0;
this = NULL;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->got_addr = 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_addr;
#if 0
plt_addr = 0;
object->plt_size = 0;
this = NULL;
ooff = _dl_find_symbol("__plt_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
plt_addr = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__plt_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL);
if (this != NULL)
object->plt_size = ooff + this->st_value - plt_addr;
#endif
if (object->got_addr == 0)
object->got_start = 0;
else {
object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz);
object->got_size += object->got_addr - object->got_start;
object->got_size = ELF_ROUND(object->got_size, _dl_pagesz);
}
#if 0
if (plt_addr == 0)
object->plt_start = 0;
else {
object->plt_start = ELF_TRUNC(plt_addr, _dl_pagesz);
object->plt_size += plt_addr - object->plt_start;
object->plt_size = ELF_ROUND(object->plt_size, _dl_pagesz);
}
#endif
if (object->traced)
lazy = 1;
if (!lazy) {
fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
} else {
if (object->obj_base != 0) {
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->obj_base +
rela[i].r_offset);
*addr += object->obj_base;
}
}
}
if (object->got_size != 0) {
_dl_mprotect((void*)object->got_start, object->got_size,
PROT_READ);
}
/* PLT is already RO, no point in mprotecting it, just do GOT */
#if 0
if (object->plt_size != 0)
_dl_mprotect((void*)object->plt_start, object->plt_size,
PROT_READ|PROT_EXEC);
#endif
return (fails);
}
