559 lines
14 KiB
C
559 lines
14 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*
|
|
* Copyright 1996, 1997, 1998, 1999 John D. Polstra.
|
|
* All rights reserved.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* Dynamic linker for ELF.
|
|
*
|
|
* John Polstra <jdp@polstra.com>.
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/mman.h>
|
|
#include <machine/segments.h>
|
|
#include <machine/sysarch.h>
|
|
|
|
#include <dlfcn.h>
|
|
#include <err.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdarg.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
#include "debug.h"
|
|
#include "rtld.h"
|
|
#include "rtld_tls.h"
|
|
|
|
/*
|
|
* Process the special R_386_COPY relocations in the main program. These
|
|
* copy data from a shared object into a region in the main program's BSS
|
|
* segment.
|
|
*
|
|
* Returns 0 on success, -1 on failure.
|
|
*/
|
|
int
|
|
do_copy_relocations(Obj_Entry *dstobj)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
|
|
|
|
rellim = (const Elf_Rel *)((const char *)dstobj->rel + dstobj->relsize);
|
|
for (rel = dstobj->rel; rel < rellim; rel++) {
|
|
if (ELF_R_TYPE(rel->r_info) == R_386_COPY) {
|
|
void *dstaddr;
|
|
const Elf_Sym *dstsym;
|
|
const char *name;
|
|
size_t size;
|
|
const void *srcaddr;
|
|
const Elf_Sym *srcsym;
|
|
const Obj_Entry *srcobj, *defobj;
|
|
SymLook req;
|
|
int res;
|
|
|
|
dstaddr = (void *)(dstobj->relocbase + rel->r_offset);
|
|
dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info);
|
|
name = dstobj->strtab + dstsym->st_name;
|
|
size = dstsym->st_size;
|
|
symlook_init(&req, name);
|
|
req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rel->r_info));
|
|
req.flags = SYMLOOK_EARLY;
|
|
|
|
for (srcobj = globallist_next(dstobj); srcobj != NULL;
|
|
srcobj = globallist_next(srcobj)) {
|
|
res = symlook_obj(&req, srcobj);
|
|
if (res == 0) {
|
|
srcsym = req.sym_out;
|
|
defobj = req.defobj_out;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (srcobj == NULL) {
|
|
_rtld_error("Undefined symbol \"%s\" referenced from COPY"
|
|
" relocation in %s", name, dstobj->path);
|
|
return -1;
|
|
}
|
|
|
|
srcaddr = (const void *)(defobj->relocbase + srcsym->st_value);
|
|
memcpy(dstaddr, srcaddr, size);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Initialize the special GOT entries. */
|
|
void
|
|
init_pltgot(Obj_Entry *obj)
|
|
{
|
|
if (obj->pltgot != NULL) {
|
|
obj->pltgot[1] = (Elf_Addr) obj;
|
|
obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
|
|
}
|
|
}
|
|
|
|
/* Process the non-PLT relocations. */
|
|
int
|
|
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
|
|
RtldLockState *lockstate)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
SymCache *cache;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
Elf_Addr *where, symval, add;
|
|
int r;
|
|
|
|
r = -1;
|
|
/*
|
|
* The dynamic loader may be called from a thread, we have
|
|
* limited amounts of stack available so we cannot use alloca().
|
|
*/
|
|
if (obj != obj_rtld) {
|
|
cache = calloc(obj->dynsymcount, sizeof(SymCache));
|
|
/* No need to check for NULL here */
|
|
} else
|
|
cache = NULL;
|
|
|
|
/* Appease some compilers. */
|
|
symval = 0;
|
|
def = NULL;
|
|
|
|
rellim = (const Elf_Rel *)((const char *)obj->rel + obj->relsize);
|
|
for (rel = obj->rel; rel < rellim; rel++) {
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_32:
|
|
case R_386_PC32:
|
|
case R_386_GLOB_DAT:
|
|
case R_386_TLS_TPOFF:
|
|
case R_386_TLS_TPOFF32:
|
|
case R_386_TLS_DTPMOD32:
|
|
case R_386_TLS_DTPOFF32:
|
|
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
|
|
flags, cache, lockstate);
|
|
if (def == NULL)
|
|
goto done;
|
|
if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_32:
|
|
case R_386_PC32:
|
|
case R_386_GLOB_DAT:
|
|
if ((flags & SYMLOOK_IFUNC) == 0) {
|
|
obj->non_plt_gnu_ifunc = true;
|
|
continue;
|
|
}
|
|
symval = (Elf_Addr)rtld_resolve_ifunc(
|
|
defobj, def);
|
|
break;
|
|
case R_386_TLS_TPOFF:
|
|
case R_386_TLS_TPOFF32:
|
|
case R_386_TLS_DTPMOD32:
|
|
case R_386_TLS_DTPOFF32:
|
|
_rtld_error("%s: IFUNC for TLS reloc",
|
|
obj->path);
|
|
goto done;
|
|
}
|
|
} else {
|
|
if ((flags & SYMLOOK_IFUNC) != 0)
|
|
continue;
|
|
symval = (Elf_Addr)defobj->relocbase +
|
|
def->st_value;
|
|
}
|
|
break;
|
|
default:
|
|
if ((flags & SYMLOOK_IFUNC) != 0)
|
|
continue;
|
|
break;
|
|
}
|
|
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
|
|
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_NONE:
|
|
break;
|
|
case R_386_32:
|
|
*where += symval;
|
|
break;
|
|
case R_386_PC32:
|
|
/*
|
|
* I don't think the dynamic linker should ever
|
|
* see this type of relocation. But the
|
|
* binutils-2.6 tools sometimes generate it.
|
|
*/
|
|
*where += symval - (Elf_Addr)where;
|
|
break;
|
|
case R_386_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->mainprog) {
|
|
_rtld_error("%s: Unexpected R_386_COPY "
|
|
"relocation in shared library", obj->path);
|
|
goto done;
|
|
}
|
|
break;
|
|
case R_386_GLOB_DAT:
|
|
*where = symval;
|
|
break;
|
|
case R_386_RELATIVE:
|
|
*where += (Elf_Addr)obj->relocbase;
|
|
break;
|
|
case R_386_TLS_TPOFF:
|
|
case R_386_TLS_TPOFF32:
|
|
/*
|
|
* We lazily allocate offsets for static TLS
|
|
* as we see the first relocation that
|
|
* references the TLS block. This allows us to
|
|
* support (small amounts of) static TLS in
|
|
* dynamically loaded modules. If we run out
|
|
* of space, we generate an error.
|
|
*/
|
|
if (!defobj->tls_static) {
|
|
if (!allocate_tls_offset(
|
|
__DECONST(Obj_Entry *, defobj))) {
|
|
_rtld_error("%s: No space available "
|
|
"for static Thread Local Storage",
|
|
obj->path);
|
|
goto done;
|
|
}
|
|
}
|
|
add = (Elf_Addr)(def->st_value - defobj->tlsoffset);
|
|
if (ELF_R_TYPE(rel->r_info) == R_386_TLS_TPOFF)
|
|
*where += add;
|
|
else
|
|
*where -= add;
|
|
break;
|
|
case R_386_TLS_DTPMOD32:
|
|
*where += (Elf_Addr)defobj->tlsindex;
|
|
break;
|
|
case R_386_TLS_DTPOFF32:
|
|
*where += (Elf_Addr) def->st_value;
|
|
break;
|
|
case R_386_IRELATIVE:
|
|
obj->irelative_nonplt = true;
|
|
break;
|
|
default:
|
|
_rtld_error("%s: Unsupported relocation type %d"
|
|
" in non-PLT relocations\n", obj->path,
|
|
ELF_R_TYPE(rel->r_info));
|
|
goto done;
|
|
}
|
|
}
|
|
r = 0;
|
|
done:
|
|
free(cache);
|
|
return (r);
|
|
}
|
|
|
|
/* Process the PLT relocations. */
|
|
int
|
|
reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize);
|
|
for (rel = obj->pltrel; rel < rellim; rel++) {
|
|
Elf_Addr *where/*, val*/;
|
|
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_JMP_SLOT:
|
|
/* Relocate the GOT slot pointing into the PLT. */
|
|
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
|
|
*where += (Elf_Addr)obj->relocbase;
|
|
break;
|
|
|
|
case R_386_IRELATIVE:
|
|
obj->irelative = true;
|
|
break;
|
|
|
|
default:
|
|
_rtld_error("Unknown relocation type %x in PLT",
|
|
ELF_R_TYPE(rel->r_info));
|
|
return (-1);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Relocate the jump slots in an object. */
|
|
int
|
|
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
if (obj->jmpslots_done)
|
|
return 0;
|
|
rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize);
|
|
for (rel = obj->pltrel; rel < rellim; rel++) {
|
|
Elf_Addr *where, target;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_JMP_SLOT:
|
|
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
|
|
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
|
|
SYMLOOK_IN_PLT | flags, NULL, lockstate);
|
|
if (def == NULL)
|
|
return (-1);
|
|
if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
|
|
obj->gnu_ifunc = true;
|
|
continue;
|
|
}
|
|
target = (Elf_Addr)(defobj->relocbase + def->st_value);
|
|
reloc_jmpslot(where, target, defobj, obj, rel);
|
|
break;
|
|
|
|
case R_386_IRELATIVE:
|
|
break;
|
|
|
|
default:
|
|
_rtld_error("Unknown relocation type %x in PLT",
|
|
ELF_R_TYPE(rel->r_info));
|
|
return (-1);
|
|
}
|
|
}
|
|
|
|
obj->jmpslots_done = true;
|
|
return 0;
|
|
}
|
|
|
|
/* Fixup the jump slot at "where" to transfer control to "target". */
|
|
Elf_Addr
|
|
reloc_jmpslot(Elf_Addr *where, Elf_Addr target,
|
|
const Obj_Entry *obj __unused, const Obj_Entry *refobj __unused,
|
|
const Elf_Rel *rel __unused)
|
|
{
|
|
#ifdef dbg
|
|
dbg("reloc_jmpslot: *%p = %p", where, (void *)target);
|
|
#endif
|
|
if (!ld_bind_not)
|
|
*where = target;
|
|
return (target);
|
|
}
|
|
|
|
static void
|
|
reloc_iresolve_one(Obj_Entry *obj, const Elf_Rel *rel,
|
|
RtldLockState *lockstate)
|
|
{
|
|
Elf_Addr *where, target;
|
|
|
|
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
|
|
lock_release(rtld_bind_lock, lockstate);
|
|
target = call_ifunc_resolver(obj->relocbase + *where);
|
|
wlock_acquire(rtld_bind_lock, lockstate);
|
|
*where = target;
|
|
}
|
|
|
|
int
|
|
reloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
if (!obj->irelative)
|
|
return (0);
|
|
obj->irelative = false;
|
|
rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize);
|
|
for (rel = obj->pltrel; rel < rellim; rel++) {
|
|
if (ELF_R_TYPE(rel->r_info) == R_386_IRELATIVE)
|
|
reloc_iresolve_one(obj, rel, lockstate);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
reloc_iresolve_nonplt(Obj_Entry *obj, RtldLockState *lockstate)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
if (!obj->irelative_nonplt)
|
|
return (0);
|
|
obj->irelative_nonplt = false;
|
|
rellim = (const Elf_Rel *)((const char *)obj->rel + obj->relsize);
|
|
for (rel = obj->rel; rel < rellim; rel++) {
|
|
if (ELF_R_TYPE(rel->r_info) == R_386_IRELATIVE)
|
|
reloc_iresolve_one(obj, rel, lockstate);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
|
|
{
|
|
const Elf_Rel *rellim;
|
|
const Elf_Rel *rel;
|
|
|
|
if (!obj->gnu_ifunc)
|
|
return (0);
|
|
rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize);
|
|
for (rel = obj->pltrel; rel < rellim; rel++) {
|
|
Elf_Addr *where, target;
|
|
const Elf_Sym *def;
|
|
const Obj_Entry *defobj;
|
|
|
|
switch (ELF_R_TYPE(rel->r_info)) {
|
|
case R_386_JMP_SLOT:
|
|
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
|
|
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
|
|
SYMLOOK_IN_PLT | flags, NULL, lockstate);
|
|
if (def == NULL)
|
|
return (-1);
|
|
if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
|
|
continue;
|
|
lock_release(rtld_bind_lock, lockstate);
|
|
target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
|
|
wlock_acquire(rtld_bind_lock, lockstate);
|
|
reloc_jmpslot(where, target, defobj, obj, rel);
|
|
break;
|
|
}
|
|
}
|
|
|
|
obj->gnu_ifunc = false;
|
|
return (0);
|
|
}
|
|
|
|
uint32_t cpu_feature, cpu_feature2, cpu_stdext_feature, cpu_stdext_feature2;
|
|
|
|
static void
|
|
rtld_cpuid_count(int idx, int cnt, u_int *p)
|
|
{
|
|
|
|
__asm __volatile(
|
|
" pushl %%ebx\n"
|
|
" cpuid\n"
|
|
" movl %%ebx,%1\n"
|
|
" popl %%ebx\n"
|
|
: "=a" (p[0]), "=r" (p[1]), "=c" (p[2]), "=d" (p[3])
|
|
: "0" (idx), "2" (cnt));
|
|
}
|
|
|
|
void
|
|
ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused)
|
|
{
|
|
u_int p[4], cpu_high;
|
|
int cpuid_supported;
|
|
|
|
__asm __volatile(
|
|
" pushfl\n"
|
|
" popl %%eax\n"
|
|
" movl %%eax,%%ecx\n"
|
|
" xorl $0x200000,%%eax\n"
|
|
" pushl %%eax\n"
|
|
" popfl\n"
|
|
" pushfl\n"
|
|
" popl %%eax\n"
|
|
" xorl %%eax,%%ecx\n"
|
|
" je 1f\n"
|
|
" movl $1,%0\n"
|
|
" jmp 2f\n"
|
|
"1: movl $0,%0\n"
|
|
"2:\n"
|
|
: "=r" (cpuid_supported) : : "eax", "ecx");
|
|
if (!cpuid_supported)
|
|
return;
|
|
|
|
rtld_cpuid_count(1, 0, p);
|
|
cpu_feature = p[3];
|
|
cpu_feature2 = p[2];
|
|
rtld_cpuid_count(0, 0, p);
|
|
cpu_high = p[0];
|
|
if (cpu_high >= 7) {
|
|
rtld_cpuid_count(7, 0, p);
|
|
cpu_stdext_feature = p[1];
|
|
cpu_stdext_feature2 = p[2];
|
|
}
|
|
}
|
|
|
|
void
|
|
allocate_initial_tls(Obj_Entry *objs)
|
|
{
|
|
void* tls;
|
|
|
|
/*
|
|
* Fix the size of the static TLS block by using the maximum
|
|
* offset allocated so far and adding a bit for dynamic modules to
|
|
* use.
|
|
*/
|
|
tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
|
|
tls = allocate_tls(objs, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN);
|
|
_tcb_set(tls);
|
|
}
|
|
|
|
/* GNU ABI */
|
|
__attribute__((__regparm__(1)))
|
|
void *
|
|
___tls_get_addr(tls_index *ti)
|
|
{
|
|
uintptr_t **dtvp;
|
|
|
|
dtvp = &_tcb_get()->tcb_dtv;
|
|
return (tls_get_addr_common(dtvp, ti->ti_module, ti->ti_offset));
|
|
}
|
|
|
|
/* Sun ABI */
|
|
void *
|
|
__tls_get_addr(tls_index *ti)
|
|
{
|
|
uintptr_t **dtvp;
|
|
|
|
dtvp = &_tcb_get()->tcb_dtv;
|
|
return (tls_get_addr_common(dtvp, ti->ti_module, ti->ti_offset));
|
|
}
|
|
|
|
size_t
|
|
calculate_tls_offset(size_t prev_offset, size_t prev_size __unused,
|
|
size_t size, size_t align, size_t offset)
|
|
{
|
|
size_t res;
|
|
|
|
/*
|
|
* res is the smallest integer satisfying res - prev_offset >= size
|
|
* and (-res) % p_align = p_vaddr % p_align (= p_offset % p_align).
|
|
*/
|
|
res = prev_offset + size + align - 1;
|
|
res -= (res + offset) & (align - 1);
|
|
return (res);
|
|
}
|
|
|
|
size_t
|
|
calculate_first_tls_offset(size_t size, size_t align, size_t offset)
|
|
{
|
|
return (calculate_tls_offset(0, 0, size, align, offset));
|
|
}
|