218 lines
6.6 KiB
C
218 lines
6.6 KiB
C
/* $NetBSD: reloc.c,v 1.83 2004/05/17 13:16:02 skrll 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"
|
|
|
|
#ifndef RTLD_INHIBIT_COPY_RELOCS
|
|
static int _rtld_do_copy_relocation(const Obj_Entry *, const Elf_Rela *);
|
|
|
|
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 = NULL;
|
|
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);
|
|
(void)memcpy(dstaddr, srcaddr, size);
|
|
rdbg(("COPY %s %s %s --> src=%p dst=%p *dst= %p size %ld",
|
|
dstobj->path, srcobj->path, name, (void *)srcaddr,
|
|
(void *)dstaddr, (void *)*(long *)dstaddr, (long)size));
|
|
return (0);
|
|
}
|
|
#endif /* RTLD_INHIBIT_COPY_RELOCS */
|
|
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
#ifndef RTLD_INHIBIT_COPY_RELOCS
|
|
|
|
/* COPY relocations are invalid elsewhere */
|
|
assert(!dstobj->isdynamic);
|
|
|
|
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 /* RTLD_INHIBIT_COPY_RELOCS */
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
rdbg((" 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;
|
|
}
|
|
}
|
|
dbg(("doing non-PLT relocations"));
|
|
if (_rtld_relocate_nonplt_objects(obj) < 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;
|
|
}
|
|
}
|
|
dbg(("doing lazy PLT binding"));
|
|
if (_rtld_relocate_plt_lazy(obj) < 0)
|
|
ok = 0;
|
|
#if defined(__hppa__)
|
|
bind_now = 1;
|
|
#endif
|
|
#if defined(__i386__) || defined(__arm__) || defined(__hppa__)
|
|
if (bind_now) {
|
|
dbg(("doing immediate PLT binding"));
|
|
if (_rtld_relocate_plt_objects(obj) < 0)
|
|
ok = 0;
|
|
}
|
|
#endif
|
|
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 = dlopen;
|
|
obj->dlsym = dlsym;
|
|
obj->dlerror = dlerror;
|
|
obj->dlclose = dlclose;
|
|
obj->dladdr = dladdr;
|
|
|
|
dbg(("fixing up PLTGOT"));
|
|
/* Set the special PLTGOT entries. */
|
|
if (obj->pltgot != NULL)
|
|
_rtld_setup_pltgot(obj);
|
|
}
|
|
|
|
return 0;
|
|
}
|