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/*-
* 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.
*
* $FreeBSD$
*/
/*
* Dynamic linker for ELF.
*
* John Polstra <jdp@polstra.com>.
*/
#include <sys/param.h>
#include <sys/mman.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"
/*
* 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 *) ((caddr_t) 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;
unsigned long hash;
size_t size;
const void *srcaddr;
const Elf_Sym *srcsym;
Obj_Entry *srcobj;
dstaddr = (void *) (dstobj->relocbase + rel->r_offset);
dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info);
name = dstobj->strtab + dstsym->st_name;
hash = elf_hash(name);
size = dstsym->st_size;
for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next)
if ((srcsym = 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);
}
}
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)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
rellim = (const Elf_Rel *) ((caddr_t) obj->rel + obj->relsize);
for (rel = obj->rel; rel < rellim; rel++) {
Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
switch (ELF_R_TYPE(rel->r_info)) {
case R_386_NONE:
break;
case R_386_32:
{
const Elf_Sym *def;
const Obj_Entry *defobj;
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
false);
if (def == NULL)
return -1;
*where += (Elf_Addr) (defobj->relocbase + def->st_value);
}
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.
*/
{
const Elf_Sym *def;
const Obj_Entry *defobj;
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
false);
if (def == NULL)
return -1;
*where +=
(Elf_Addr) (defobj->relocbase + def->st_value) -
(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);
return -1;
}
break;
case R_386_GLOB_DAT:
{
const Elf_Sym *def;
const Obj_Entry *defobj;
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj,
false);
if (def == NULL)
return -1;
*where = (Elf_Addr) (defobj->relocbase + def->st_value);
}
break;
case R_386_RELATIVE:
*where += (Elf_Addr) obj->relocbase;
break;
default:
_rtld_error("%s: Unsupported relocation type %d"
" in non-PLT relocations\n", obj->path,
ELF_R_TYPE(rel->r_info));
return -1;
}
}
return 0;
}
/* Process the PLT relocations. */
int
reloc_plt(Obj_Entry *obj)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
rellim = (const Elf_Rel *)((char *)obj->pltrel + obj->pltrelsize);
for (rel = obj->pltrel; rel < rellim; rel++) {
Elf_Addr *where;
assert(ELF_R_TYPE(rel->r_info) == 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;
}
return 0;
}
/* Relocate the jump slots in an object. */
int
reloc_jmpslots(Obj_Entry *obj)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
if (obj->jmpslots_done)
return 0;
rellim = (const Elf_Rel *)((char *)obj->pltrel + obj->pltrelsize);
for (rel = obj->pltrel; rel < rellim; rel++) {
Elf_Addr *where;
const Elf_Sym *def;
const Obj_Entry *defobj;
assert(ELF_R_TYPE(rel->r_info) == R_386_JMP_SLOT);
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true);
if (def == NULL)
return -1;
reloc_jmpslot(where, (Elf_Addr)(defobj->relocbase + def->st_value));
}
obj->jmpslots_done = true;
return 0;
}
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