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6be4b69715
rtld on 386 and amd64. This adds runtime bits neccessary for the use of the dispatch functions from the dynamically-linked executables and shared libraries. To allow use of external references from the dispatch function, resolution of the R_MACHINE_IRESOLVE relocations in PLT is postponed until GOT entries for PLT are prepared, and normal resolution of the GOT entries is finished. Similar to how it is done by GNU, IRELATIVE relocations are resolved in advance, instead of normal lazy handling for PLT. Move the init_pltgot() call before the relocations for the object are processed. MFC after: 3 weeks
380 lines
8.6 KiB
C
380 lines
8.6 KiB
C
/* $NetBSD: mdreloc.c,v 1.23 2003/07/26 15:04:38 mrg Exp $ */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "debug.h"
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#include "rtld.h"
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void
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init_pltgot(Obj_Entry *obj)
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{
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if (obj->pltgot != NULL) {
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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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}
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int
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do_copy_relocations(Obj_Entry *dstobj)
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{
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const Elf_Rel *rellim;
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const Elf_Rel *rel;
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assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
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rellim = (const Elf_Rel *) ((caddr_t) dstobj->rel + dstobj->relsize);
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for (rel = dstobj->rel; rel < rellim; rel++) {
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if (ELF_R_TYPE(rel->r_info) == R_ARM_COPY) {
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void *dstaddr;
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const Elf_Sym *dstsym;
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const char *name;
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size_t size;
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const void *srcaddr;
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const Elf_Sym *srcsym;
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const Obj_Entry *srcobj, *defobj;
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SymLook req;
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int res;
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dstaddr = (void *) (dstobj->relocbase + rel->r_offset);
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dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info);
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name = dstobj->strtab + dstsym->st_name;
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size = dstsym->st_size;
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symlook_init(&req, name);
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req.ventry = fetch_ventry(dstobj,
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ELF_R_SYM(rel->r_info));
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for (srcobj = dstobj->next; srcobj != NULL;
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srcobj = srcobj->next) {
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res = symlook_obj(&req, srcobj);
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if (res == 0) {
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srcsym = req.sym_out;
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defobj = req.defobj_out;
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break;
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}
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}
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if (srcobj == NULL) {
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_rtld_error(
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"Undefined symbol \"%s\" referenced from COPY relocation in %s",
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name, dstobj->path);
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return (-1);
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}
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srcaddr = (const void *)(defobj->relocbase +
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srcsym->st_value);
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memcpy(dstaddr, srcaddr, size);
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}
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}
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return 0;
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}
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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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int open();
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int _open();
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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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uint32_t size;
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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 *)((caddr_t)rel + relsz);
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size = (rellim - 1)->r_offset - rel->r_offset;
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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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static int
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reloc_nonplt_object(Obj_Entry *obj, const Elf_Rel *rel, SymCache *cache,
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RtldLockState *lockstate)
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{
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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_ARM_NONE:
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break;
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#if 1 /* XXX should not occur */
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case R_ARM_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 = find_symdef(symnum, obj, &defobj, false, cache,
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lockstate);
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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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dbg("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_ARM_ABS32: /* word32 B + S + A */
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case R_ARM_GLOB_DAT: /* word32 B + S */
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def = find_symdef(symnum, obj, &defobj, false, cache,
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lockstate);
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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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*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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store_ptr(where, tmp);
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}
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dbg("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_ARM_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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dbg("RELATIVE in %s --> %p", obj->path,
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(void *)tmp);
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break;
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case R_ARM_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->mainprog) {
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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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dbg("COPY (avoid in main)");
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break;
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default:
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dbg("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\n",
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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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return 0;
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}
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/*
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* * Process non-PLT relocations
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* */
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int
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reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, RtldLockState *lockstate)
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{
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const Elf_Rel *rellim;
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const Elf_Rel *rel;
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SymCache *cache;
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int r = -1;
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/* The relocation for the dynamic loader has already been done. */
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if (obj == obj_rtld)
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return (0);
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/*
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* The dynamic loader may be called from a thread, we have
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* limited amounts of stack available so we cannot use alloca().
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*/
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cache = calloc(obj->nchains, sizeof(SymCache));
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/* No need to check for NULL here */
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rellim = (const Elf_Rel *)((caddr_t)obj->rel + obj->relsize);
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for (rel = obj->rel; rel < rellim; rel++) {
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if (reloc_nonplt_object(obj, rel, cache, lockstate) < 0)
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goto done;
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}
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r = 0;
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done:
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if (cache != NULL)
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free(cache);
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return (r);
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}
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/*
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* * Process the PLT relocations.
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* */
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int
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reloc_plt(Obj_Entry *obj)
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{
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const Elf_Rel *rellim;
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const Elf_Rel *rel;
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rellim = (const Elf_Rel *)((char *)obj->pltrel +
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obj->pltrelsize);
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for (rel = obj->pltrel; rel < rellim; rel++) {
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Elf_Addr *where;
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assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT);
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where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
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*where += (Elf_Addr )obj->relocbase;
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}
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return (0);
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}
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/*
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* * LD_BIND_NOW was set - force relocation for all jump slots
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* */
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int
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reloc_jmpslots(Obj_Entry *obj, RtldLockState *lockstate)
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{
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const Obj_Entry *defobj;
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const Elf_Rel *rellim;
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const Elf_Rel *rel;
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const Elf_Sym *def;
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Elf_Addr *where;
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Elf_Addr target;
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rellim = (const Elf_Rel *)((char *)obj->pltrel + obj->pltrelsize);
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for (rel = obj->pltrel; rel < rellim; rel++) {
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assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT);
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where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
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def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
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true, NULL, lockstate);
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if (def == NULL) {
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dbg("reloc_jmpslots: sym not found");
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return (-1);
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}
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target = (Elf_Addr)(defobj->relocbase + def->st_value);
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reloc_jmpslot(where, target, defobj, obj,
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(const Elf_Rel *) rel);
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}
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obj->jmpslots_done = true;
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return (0);
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}
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int
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reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
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{
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/* XXX not implemented */
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return (0);
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}
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int
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reloc_gnu_ifunc(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
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{
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/* XXX not implemented */
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return (0);
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}
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Elf_Addr
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reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj,
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const Obj_Entry *obj, const Elf_Rel *rel)
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{
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assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT);
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if (*where != target)
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*where = target;
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return target;
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}
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void
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allocate_initial_tls(Obj_Entry *objs)
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{
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}
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void *
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__tls_get_addr(tls_index* ti)
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{
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return (NULL);
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}
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