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NetBSD/libexec/ld.elf_so/reloc.c

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/* $NetBSD: reloc.c,v 1.10 1999/02/24 12:20:30 pk Exp $ */
/*
* Copyright 1996 John D. Polstra.
* Copyright 1996 Matt Thomas <matt@3am-software.com>
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Polstra.
* 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.
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#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 <sys/types.h>
#include <sys/mman.h>
#include <dirent.h>
#include "debug.h"
#include "rtld.h"
#if defined(__alpha__) || defined(__powerpc__) || defined(__i386__)
/*
* XXX: These don't work for the alpha and i386; don't know about powerpc
* The alpha and the i386 avoid the problem by compiling everything PIC.
* These relocation are supposed to be writing the address of the
* function to be called on the bss.rel or bss.rela segment, but:
* - st_size == 0
* - on the i386 at least the call instruction is a direct call
* not an indirect call.
*/
static int
_rtld_do_copy_relocation(
const Obj_Entry *dstobj,
const Elf_RelA *rela)
{
void *dstaddr = (void *) (dstobj->relocbase + rela->r_offset);
const Elf_Sym *dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
const char *name = dstobj->strtab + dstsym->st_name;
unsigned long hash = _rtld_elf_hash(name);
size_t size = dstsym->st_size;
const void *srcaddr;
const Elf_Sym *srcsym;
Obj_Entry *srcobj;
for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next)
if ((srcsym = _rtld_symlook_obj(name, hash, srcobj, false)) != NULL)
break;
if (srcobj == NULL) {
_rtld_error("Undefined symbol \"%s\" referenced from COPY"
" relocation in %s", name, dstobj->path);
return -1;
}
srcaddr = (const void *) (srcobj->relocbase + srcsym->st_value);
memcpy(dstaddr, srcaddr, size);
#ifdef RTLD_DEBUG_RELOC
dbg("COPY %s %s %s --> src=%p dst=%p *dst= %p size %d",
dstobj->path, srcobj->path, name, (void *)srcaddr, (void *)dstaddr,
(void *)*(long *)dstaddr, size);
#endif
return 0;
}
#endif /* __alpha__ || __powerpc__ || __i386__ */
/*
* Process the special R_xxx_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
_rtld_do_copy_relocations(
const Obj_Entry *dstobj)
{
assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
#if defined(__alpha__) || defined(__powerpc__) || defined(__i386__)
if (dstobj->rel != NULL) {
const Elf_Rel *rel;
for (rel = dstobj->rel; rel < dstobj->rellim; ++rel) {
if (ELF_R_TYPE(rel->r_info) == R_TYPE(COPY)) {
Elf_RelA ourrela;
ourrela.r_info = rel->r_info;
ourrela.r_offset = rel->r_offset;
ourrela.r_addend = 0;
if (_rtld_do_copy_relocation(dstobj, &ourrela) < 0)
return -1;
}
}
}
if (dstobj->rela != NULL) {
const Elf_RelA *rela;
for (rela = dstobj->rela; rela < dstobj->relalim; ++rela) {
if (ELF_R_TYPE(rela->r_info) == R_TYPE(COPY)) {
if (_rtld_do_copy_relocation(dstobj, rela) < 0)
return -1;
}
}
}
#endif /* __alpha__ || __powerpc__ || __i386__ */
return 0;
}
#ifdef __sparc__
/*
* The following table holds for each relocation type:
* - the width in bits of the memory location the relocation
* applies to (not currently used)
* - the number of bits the relocation value must be shifted to the
* right (i.e. discard least significant bits) to fit into
* the appropriate field in the instruction word.
* - flags indicating whether
* * the relocation involves a symbol
* * the relocation is relative to the current position
* * the relocation is for a GOT entry
* * the relocation is relative to the load address
*
*/
#define _RF_S 0x80000000 /* Resolve symbol */
#define _RF_A 0x40000000 /* Use addend */
#define _RF_P 0x20000000 /* Location relative */
#define _RF_G 0x10000000 /* GOT offset */
#define _RF_B 0x08000000 /* Load address relative */
#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */
#define _RF_RS(s) ( (s) & 0xff) /* right shift */
static int reloc_target_flags[] = {
0, /* NONE */
_RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */
_RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */
_RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */
_RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */
_RF_SZ(32) | _RF_RS(0), /* COPY */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */
_RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PLT32 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HIPLT22 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT22 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 11 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 64 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HH22 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HM10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LM22 */
_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP16 */
_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP19 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 7 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 5 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 6 */
};
#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0)
#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0)
#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff)
#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff)
static int reloc_target_bitmask[] = {
#define _BM(x) (~(-(1ULL << (x))))
0, /* NONE */
_BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */
_BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */
_BM(30), _BM(22), /* WDISP30, WDISP22 */
_BM(22), _BM(22), /* HI22, _22 */
_BM(13), _BM(10), /* RELOC_13, _LO10 */
_BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */
_BM(10), _BM(22), /* _PC10, _PC22 */
_BM(30), 0, /* _WPLT30, _COPY */
-1, -1, _BM(22), /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
_BM(32), _BM(32), /* _UA32, PLT32 */
_BM(22), _BM(10), /* _HIPLT22, LOPLT10 */
_BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */
_BM(10), _BM(11), -1, /* _10, _11, _64 */
_BM(10), _BM(22), /* _OLO10, _HH22 */
_BM(10), _BM(22), /* _HM10, _LM22 */
_BM(16), _BM(19), /* _WDISP16, _WDISP19 */
-1, /* GLOB_JMP */
_BM(7), _BM(5), _BM(6) /* _7, _5, _6 */
#undef _BM
};
#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
static int
_rtld_relocate_nonplt_object(
const Obj_Entry *obj,
const Elf_RelA *rela)
{
Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
Elf_Word type, value, mask;
type = ELF_R_TYPE(rela->r_info);
if (type == R_TYPE(NONE))
return (0);
/*
* We use the fact that relocation types are an `enum'
* Note: R_SPARC_6 is currently numerically largest.
*/
if (type > R_TYPE(6))
return (-1);
value = rela->r_addend;
if (RELOC_RESOLVE_SYMBOL(type)) {
const Elf_Sym *def;
const Obj_Entry *defobj;
/* Find the symbol */
def = _rtld_find_symdef(_rtld_objlist, rela->r_info,
NULL, obj, &defobj, false);
if (def == NULL)
return (-1);
/* Add in the symbol's absolute address */
value += (Elf_Word)(defobj->relocbase + def->st_value);
}
if (RELOC_PC_RELATIVE(type)) {
value -= (Elf_Word)where;
}
mask = RELOC_VALUE_BITMASK(type);
value >>= RELOC_VALUE_RIGHTSHIFT(type);
value &= mask;
/* We ignore alignment restrictions here */
*where &= ~mask;
*where |= value;
return (0);
}
static int
__rtld_relocate_plt_object(
const Obj_Entry *obj,
const Elf_RelA *rela,
bool bind_now,
caddr_t *addrp)
{
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
Elf_Addr value;
if (bind_now == 0 && obj->pltgot != NULL)
return (0);
/* Fully resolve procedure addresses now */
assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
def = _rtld_find_symdef(_rtld_objlist, rela->r_info,
NULL, obj, &defobj, true);
if (def == NULL)
return (-1);
value = (Elf_Addr) (defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("bind now %d/fixup in %s --> old=%p new=%p",
(int)bind_now,
defobj->strtab + def->st_name,
(void *)*where, (void *)value);
#endif
/*
* At the PLT entry pointed at by `where', we now construct
* a direct transfer to the now fully resolved function
* address. The resulting code in the jump slot is:
*
* sethi %hi(addr), %g1
* jmp %g1+%lo(addr)
* nop ! delay slot
*/
#define SETHI 0x03000000
#define JMP 0x81c06000
#define NOP 0x01000000
where[0] = SETHI | ((value >> 10) & 0x003fffff);
where[1] = JMP | (value & 0x000003ff);
where[2] = NOP;
if (addrp != NULL)
*addrp = (caddr_t)value;
return (0);
}
#define _rtld_relocate_plt_object(obj, rela, bind_now) \
__rtld_relocate_plt_object(obj, rela, bind_now, NULL)
caddr_t
_rtld_bind(
const Obj_Entry *obj,
Elf_Word reloff)
{
const Elf_RelA *rela;
Elf_RelA ourrela;
caddr_t addr;
if (obj->pltrel != NULL) {
const Elf_Rel *rel;
rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
ourrela.r_info = rel->r_info;
ourrela.r_offset = rel->r_offset;
rela = &ourrela;
} else {
rela = (const Elf_RelA *) ((caddr_t) obj->pltrela + reloff);
}
if (__rtld_relocate_plt_object(obj, rela, true, &addr) < 0)
_rtld_die();
return (addr);
return *(caddr_t *)(obj->relocbase + rela->r_offset);
}
#else /* __sparc__ */
static int
_rtld_relocate_nonplt_object(
const Obj_Entry *obj,
const Elf_RelA *rela)
{
Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
switch (ELF_R_TYPE(rela->r_info)) {
case R_TYPE(NONE):
break;
#ifdef __i386__
case R_TYPE(GOT32): {
const Elf_Sym *def;
const Obj_Entry *defobj;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
if (*where != (Elf_Addr) (defobj->relocbase + def->st_value))
*where = (Elf_Addr) (defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("GOT32 %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
case R_TYPE(PC32):
/*
* I don't think the dynamic linker should ever see this
* type of relocation. But the binutils-2.6 tools sometimes
* generate it.
*/
{
const Elf_Sym *def;
const Obj_Entry *defobj;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
*where += (Elf_Addr) (defobj->relocbase + def->st_value)
- (Elf_Addr) where;
#ifdef RTLD_DEBUG_RELOC
dbg("PC32 %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
case R_TYPE(32): {
const Elf_Sym *def;
const Obj_Entry *defobj;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
*where += (Elf_Addr)(defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("32 %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
#endif /* __i386__ */
#ifdef __alpha__
case R_ALPHA_REFQUAD: {
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr tmp_value;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
tmp_value = (Elf_Addr) (defobj->relocbase + def->st_value)
+ *where + rela->r_addend;
if (*where != tmp_value)
*where = tmp_value;
#ifdef RTLD_DEBUG_RELOC
dbg("REFQUAD %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
#endif /* __alpha__ */
#if defined(__i386__) || defined(__alpha__)
case R_TYPE(GLOB_DAT):
{
const Elf_Sym *def;
const Obj_Entry *defobj;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
if (*where != (Elf_Addr) (defobj->relocbase + def->st_value))
*where = (Elf_Addr) (defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("GLOB_DAT %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
case R_TYPE(RELATIVE): {
extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
extern Elf_Dyn _DYNAMIC;
if (obj != &_rtld_objself ||
(caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ ||
(caddr_t)where >= (caddr_t)&_DYNAMIC) {
*where += (Elf_Addr) obj->relocbase;
#ifdef RTLD_DEBUG_RELOC
dbg("RELATIVE in %s --> %p", obj->path, (void *)*where);
#endif
}
#ifdef RTLD_DEBUG_RELOC
else
dbg("RELATIVE in %s stays at %p", obj->path, (void *)*where);
#endif
break;
}
case R_TYPE(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_COPY relocation in shared library",
obj->path);
return -1;
}
#ifdef RTLD_DEBUG_RELOC
dbg("COPY (avoid in main)");
#endif
break;
}
#endif /* __i386__ || __alpha__ */
#ifdef __mips__
case R_TYPE(REL32): {
/* 32-bit PC-relative reference */
const Elf_Sym *def;
const Obj_Entry *defobj;
def = obj->symtab + ELF_R_SYM(rela->r_info);
if (ELF_SYM_BIND(def->st_info) == Elf_estb_local &&
(ELF_SYM_TYPE(def->st_info) == Elf_estt_section ||
ELF_SYM_TYPE(def->st_info) == Elf_estt_notype)) {
*where += (Elf_Addr) obj->relocbase;
#ifdef RTLD_DEBUG_RELOC
dbg("REL32 in %s --> %p", obj->path, (void *)*where);
#endif
} else {
/* XXX maybe do something re: bootstrapping? */
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
&defobj, false);
if (def == NULL)
return -1;
*where += (Elf_Addr)(defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("REL32 %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
}
break;
}
#endif /* mips */
#ifdef __powerpc__
case R_TYPE(32): /* word32 S + A */
case R_TYPE(GLOB_DAT): { /* word32 S + A */
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr x;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false);
if (def == NULL)
return -1;
x = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend);
if (*where != x)
*where = x;
#ifdef RTLD_DEBUG_RELOC
dbg("32/GLOB_DAT %s in %s --> %p in %s",
defobj->strtab + def->st_name, obj->path,
(void *)*where, defobj->path);
#endif
break;
}
case R_TYPE(COPY):
#ifdef RTLD_DEBUG_RELOC
dbg("COPY");
#endif
break;
case R_TYPE(JMP_SLOT):
#ifdef RTLD_DEBUG_RELOC
dbg("JMP_SLOT");
#endif
break;
case R_TYPE(RELATIVE): { /* word32 B + A */
if (obj == &_rtld_objself &&
*where == (Elf_Addr)obj->relocbase + rela->r_addend)
break; /* GOT - already done */
*where = (Elf_Addr)obj->relocbase + rela->r_addend;
#ifdef RTLD_DEBUG_RELOC
dbg("RELATIVE in %s --> %p", obj->path, (void *)*where);
#endif
break;
}
#endif /* __powerpc__ */
default: {
const Elf_Sym *def;
const Obj_Entry *defobj;
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, true);
dbg("sym = %lu, type = %lu, offset = %p, addend = %p, contents = %p, symbol = %s",
(u_long)ELF_R_SYM(rela->r_info), (u_long)ELF_R_TYPE(rela->r_info),
(void *)rela->r_offset, (void *)rela->r_addend, (void *)*where,
def ? defobj->strtab + def->st_name : "??");
_rtld_error("%s: Unsupported relocation type %d in non-PLT relocations\n",
obj->path, ELF_R_TYPE(rela->r_info));
return -1;
}
}
return 0;
}
static int
_rtld_relocate_plt_object(
const Obj_Entry *obj,
const Elf_RelA *rela,
bool bind_now)
{
Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
Elf_Addr new_value;
/* Fully resolve procedure addresses now */
#if defined(__powerpc__)
return _rtld_reloc_powerpc_plt(obj, rela, bind_now);
#endif
#if defined(__alpha__) || defined(__i386__) /* (jrs) */
if (bind_now || obj->pltgot == NULL) {
const Elf_Sym *def;
const Obj_Entry *defobj;
assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, true);
if (def == NULL)
return -1;
new_value = (Elf_Addr) (defobj->relocbase + def->st_value);
#ifdef RTLD_DEBUG_RELOC
dbg("bind now %d/fixup in %s --> old=%p new=%p",
(int)bind_now,
defobj->strtab + def->st_name,
(void *)*where, (void *)new_value);
#endif
} else
#endif /* __alpha__ (jrs) */
if (!obj->mainprog) {
/* Just relocate the GOT slots pointing into the PLT */
new_value = *where + (Elf_Addr) (obj->relocbase);
#ifdef RTLD_DEBUG_RELOC
dbg("fixup !main in %s --> %p", obj->path, (void *)*where);
#endif
} else {
return 0;
}
/*
* Since this page is probably copy-on-write, let's not write
* it unless we really really have to.
*/
if (*where != new_value)
*where = new_value;
return 0;
}
caddr_t
_rtld_bind(
const Obj_Entry *obj,
Elf_Word reloff)
{
const Elf_RelA *rela;
Elf_RelA ourrela;
if (obj->pltrel != NULL) {
ourrela.r_info = ((const Elf_Rel *) ((caddr_t) obj->pltrel + reloff))->r_info;
ourrela.r_offset = ((const Elf_Rel *) ((caddr_t) obj->pltrel + reloff))->r_offset;
rela = &ourrela;
} else {
rela = (const Elf_RelA *) ((caddr_t) obj->pltrela + reloff);
}
if (_rtld_relocate_plt_object(obj, rela, true) < 0)
_rtld_die();
return *(caddr_t *)(obj->relocbase + rela->r_offset);
}
#endif /* __sparc__ */
/*
* Relocate newly-loaded shared objects. The argument is a pointer to
* the Obj_Entry for the first such object. All objects from the first
* to the end of the list of objects are relocated. Returns 0 on success,
* or -1 on failure.
*/
int
_rtld_relocate_objects(
Obj_Entry *first,
bool bind_now)
{
Obj_Entry *obj;
int ok = 1;
for (obj = first; obj != NULL; obj = obj->next) {
if (obj->nbuckets == 0 || obj->nchains == 0
|| obj->buckets == NULL || obj->symtab == NULL
|| obj->strtab == NULL) {
_rtld_error("%s: Shared object has no run-time symbol table",
obj->path);
return -1;
}
dbg(" relocating %s (%ld/%ld rel/rela, %ld/%ld plt rel/rela)",
obj->path,
(long)(obj->rellim - obj->rel), (long)(obj->relalim - obj->rela),
(long)(obj->pltrellim - obj->pltrel),
(long)(obj->pltrelalim - obj->pltrela));
if (obj->textrel) {
/* There are relocations to the write-protected text segment. */
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-enable text segment: %s",
obj->path, xstrerror(errno));
return -1;
}
}
if (obj->rel != NULL) {
/* Process the non-PLT relocations. */
const Elf_Rel *rel;
for (rel = obj->rel; rel < obj->rellim; ++rel) {
Elf_RelA ourrela;
ourrela.r_info = rel->r_info;
ourrela.r_offset = rel->r_offset;
#if defined(__mips__)
/* rel->r_offset is not valid on mips? */
if (ELF_R_TYPE(ourrela.r_info) == R_TYPE(NONE))
ourrela.r_addend = 0;
else
#endif
ourrela.r_addend = *(Elf_Word *) (obj->relocbase + rel->r_offset);
if (_rtld_relocate_nonplt_object(obj, &ourrela) < 0)
ok = 0;
}
}
if (obj->rela != NULL) {
/* Process the non-PLT relocations. */
const Elf_RelA *rela;
for (rela = obj->rela; rela < obj->relalim; ++rela) {
if (_rtld_relocate_nonplt_object(obj, rela) < 0)
ok = 0;
}
}
if (obj->textrel) { /* Re-protected the text segment. */
if (mprotect(obj->mapbase, obj->textsize,
PROT_READ|PROT_EXEC) == -1) {
_rtld_error("%s: Cannot write-protect text segment: %s",
obj->path, xstrerror(errno));
return -1;
}
}
/* Process the PLT relocations. */
if (obj->pltrel != NULL) {
const Elf_Rel *rel;
for (rel = obj->pltrel; rel < obj->pltrellim; ++rel) {
Elf_RelA ourrela;
ourrela.r_info = rel->r_info;
ourrela.r_offset = rel->r_offset;
ourrela.r_addend = *(Elf_Word *) (obj->relocbase + rel->r_offset);
if (_rtld_relocate_plt_object(obj, &ourrela, bind_now) < 0)
ok = 0;
}
}
if (obj->pltrela != NULL) {
const Elf_RelA *rela;
for (rela = obj->pltrela; rela < obj->pltrelalim; ++rela) {
if (_rtld_relocate_plt_object(obj, rela, bind_now) < 0)
ok = 0;
}
}
if (!ok)
return -1;
/* Set some sanity-checking numbers in the Obj_Entry. */
obj->magic = RTLD_MAGIC;
obj->version = RTLD_VERSION;
/* Fill in the dynamic linker entry points. */
obj->dlopen = _rtld_dlopen;
obj->dlsym = _rtld_dlsym;
obj->dlerror = _rtld_dlerror;
obj->dlclose = _rtld_dlclose;
/* Set the special PLTGOT entries. */
if (obj->pltgot != NULL) {
#if defined(__i386__)
obj->pltgot[1] = (Elf_Addr) obj;
obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
#endif
#if defined(__alpha__)
/* This function will be called to perform the relocation. */
obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
/* Identify this shared object */
obj->pltgot[3] = (Elf_Addr) obj;
#endif
#if defined(__mips__)
_rtld_relocate_mips_got(obj);
obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
/* XXX only if obj->pltgot[1] & 0x80000000 ?? */
obj->pltgot[1] |= (Elf_Addr) obj;
#endif
#if defined(__powerpc__)
_rtld_setup_powerpc_plt(obj);
#endif
#if defined(__sparc__)
/*
* PLTGOT is the PLT on the sparc.
* The first entry holds the call the dynamic linker.
* We construct a `call' instruction that transfers
* to `_rtld_bind_start()'.
* The second entry holds the object identification.
* Note: each PLT entry is three words long.
*/
obj->pltgot[1] = 0x40000000 |
((Elf_Addr)&_rtld_bind_start - (Elf_Addr)&obj->pltgot[1]);
obj->pltgot[3] = (Elf_Addr) obj;
#endif
}
}
return 0;
}
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