e83f7ba2c9
. file- and functionality-compatible with previous situation
(FreeBSD csu) (with a crt1.o -> crt0.o symlink in /usr/lib)
. harmonizes source with netbsd
. harmonizes linker invocation (e.g. clang) with netbsd
. helpful to get some arm code in there for the arm port project
277 lines
6.7 KiB
C
277 lines
6.7 KiB
C
/* $NetBSD: mdreloc.c,v 1.34 2010/08/06 16:33:17 joerg Exp $ */
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: mdreloc.c,v 1.34 2010/08/06 16:33:17 joerg Exp $");
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#endif /* not lint */
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#include <sys/types.h>
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#include <string.h>
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#include "debug.h"
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#include "rtld.h"
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void _rtld_bind_start(void);
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void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
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caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
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void
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_rtld_setup_pltgot(const Obj_Entry *obj)
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{
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obj->pltgot[1] = (Elf_Addr) obj;
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obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
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}
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void
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_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
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{
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const Elf_Rel *rel = 0, *rellim;
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Elf_Addr relsz = 0;
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Elf_Addr *where;
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for (; dynp->d_tag != DT_NULL; dynp++) {
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switch (dynp->d_tag) {
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case DT_REL:
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rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr);
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break;
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case DT_RELSZ:
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relsz = dynp->d_un.d_val;
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break;
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}
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}
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rellim = (const Elf_Rel *)((const uint8_t *)rel + relsz);
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for (; rel < rellim; rel++) {
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where = (Elf_Addr *)(relocbase + rel->r_offset);
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*where += (Elf_Addr)relocbase;
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}
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}
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/*
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* It is possible for the compiler to emit relocations for unaligned data.
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* We handle this situation with these inlines.
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*/
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#define RELOC_ALIGNED_P(x) \
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(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
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static inline Elf_Addr
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load_ptr(void *where)
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{
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Elf_Addr res;
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memcpy(&res, where, sizeof(res));
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return (res);
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}
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static inline void
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store_ptr(void *where, Elf_Addr val)
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{
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memcpy(where, &val, sizeof(val));
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}
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int
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_rtld_relocate_nonplt_objects(Obj_Entry *obj)
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{
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const Elf_Rel *rel;
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for (rel = obj->rel; rel < obj->rellim; rel++) {
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Elf_Addr *where;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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Elf_Addr tmp;
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unsigned long symnum;
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where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
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symnum = ELF_R_SYM(rel->r_info);
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switch (ELF_R_TYPE(rel->r_info)) {
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case R_TYPE(NONE):
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break;
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#if 1 /* XXX should not occur */
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case R_TYPE(PC24): { /* word32 S - P + A */
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Elf32_Sword addend;
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/*
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* Extract addend and sign-extend if needed.
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*/
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addend = *where;
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if (addend & 0x00800000)
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addend |= 0xff000000;
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def = _rtld_find_symdef(symnum, obj, &defobj, false);
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if (def == NULL)
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return -1;
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tmp = (Elf_Addr)obj->relocbase + def->st_value
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- (Elf_Addr)where + (addend << 2);
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if ((tmp & 0xfe000000) != 0xfe000000 &&
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(tmp & 0xfe000000) != 0) {
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_rtld_error(
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"%s: R_ARM_PC24 relocation @ %p to %s failed "
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"(displacement %ld (%#lx) out of range)",
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obj->path, where,
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obj->strtab + obj->symtab[symnum].st_name,
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(long) tmp, (long) tmp);
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return -1;
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}
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tmp >>= 2;
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*where = (*where & 0xff000000) | (tmp & 0x00ffffff);
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rdbg(("PC24 %s in %s --> %p @ %p in %s",
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obj->strtab + obj->symtab[symnum].st_name,
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obj->path, (void *)*where, where, defobj->path));
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break;
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}
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#endif
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case R_TYPE(ABS32): /* word32 B + S + A */
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case R_TYPE(GLOB_DAT): /* word32 B + S */
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def = _rtld_find_symdef(symnum, obj, &defobj, false);
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if (def == NULL)
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return -1;
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if (__predict_true(RELOC_ALIGNED_P(where))) {
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tmp = *where + (Elf_Addr)defobj->relocbase +
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def->st_value;
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/* Set the Thumb bit, if needed. */
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if (ELF_ST_TYPE(def->st_info) == STT_ARM_TFUNC)
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tmp |= 1;
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*where = tmp;
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} else {
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tmp = load_ptr(where) +
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(Elf_Addr)defobj->relocbase +
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def->st_value;
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/* Set the Thumb bit, if needed. */
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if (ELF_ST_TYPE(def->st_info) == STT_ARM_TFUNC)
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tmp |= 1;
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store_ptr(where, tmp);
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}
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rdbg(("ABS32/GLOB_DAT %s in %s --> %p @ %p in %s",
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obj->strtab + obj->symtab[symnum].st_name,
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obj->path, (void *)tmp, where, defobj->path));
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break;
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case R_TYPE(RELATIVE): /* word32 B + A */
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if (__predict_true(RELOC_ALIGNED_P(where))) {
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tmp = *where + (Elf_Addr)obj->relocbase;
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*where = tmp;
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} else {
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tmp = load_ptr(where) +
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(Elf_Addr)obj->relocbase;
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store_ptr(where, tmp);
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}
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rdbg(("RELATIVE in %s --> %p", obj->path,
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(void *)tmp));
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break;
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case R_TYPE(COPY):
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/*
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* These are deferred until all other relocations have
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* been done. All we do here is make sure that the
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* COPY relocation is not in a shared library. They
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* are allowed only in executable files.
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*/
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if (obj->isdynamic) {
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_rtld_error(
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"%s: Unexpected R_COPY relocation in shared library",
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obj->path);
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return -1;
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}
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rdbg(("COPY (avoid in main)"));
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break;
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default:
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rdbg(("sym = %lu, type = %lu, offset = %p, "
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"contents = %p, symbol = %s",
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symnum, (u_long)ELF_R_TYPE(rel->r_info),
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(void *)rel->r_offset, (void *)load_ptr(where),
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obj->strtab + obj->symtab[symnum].st_name));
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_rtld_error("%s: Unsupported relocation type %ld "
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"in non-PLT relocations",
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obj->path, (u_long) ELF_R_TYPE(rel->r_info));
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return -1;
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}
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}
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return 0;
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}
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int
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_rtld_relocate_plt_lazy(const Obj_Entry *obj)
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{
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const Elf_Rel *rel;
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if (!obj->relocbase)
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return 0;
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for (rel = obj->pltrel; rel < obj->pltrellim; rel++) {
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Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
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assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JUMP_SLOT));
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/* Just relocate the GOT slots pointing into the PLT */
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*where += (Elf_Addr)obj->relocbase;
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rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
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}
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return 0;
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}
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static int
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_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rel *rel,
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Elf_Addr *tp)
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{
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Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
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Elf_Addr new_value;
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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unsigned long info = rel->r_info;
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assert(ELF_R_TYPE(info) == R_TYPE(JUMP_SLOT));
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def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
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if (__predict_false(def == NULL))
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return -1;
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if (__predict_false(def == &_rtld_sym_zero))
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return 0;
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new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
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/* Set the Thumb bit, if needed. */
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if (ELF_ST_TYPE(def->st_info) == STT_ARM_TFUNC)
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new_value |= 1;
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rdbg(("bind now/fixup in %s --> old=%p new=%p",
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defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
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if (*where != new_value)
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*where = new_value;
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if (tp)
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*tp = new_value;
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return 0;
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}
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caddr_t
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_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
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{
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const Elf_Rel *rel = (const Elf_Rel *)((const uint8_t *)obj->pltrel + reloff);
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Elf_Addr new_value = 0; /* XXX gcc */
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int err;
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err = _rtld_relocate_plt_object(obj, rel, &new_value);
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if (err)
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_rtld_die();
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return (caddr_t)new_value;
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}
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int
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_rtld_relocate_plt_objects(const Obj_Entry *obj)
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{
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const Elf_Rel *rel;
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int err = 0;
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for (rel = obj->pltrel; rel < obj->pltrellim; rel++) {
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err = _rtld_relocate_plt_object(obj, rel, NULL);
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if (err)
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break;
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}
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return err;
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}
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