f2b0f935d7
from zero fill. * elf/dl-lookup.c (_dl_lookup_symbol): Take new flag arg NOSELF; if nonzero, don't let *REF satisfy the reference itself. * elf/link.h (_dl_lookup_symbol): Add new arg NOSELF in decl. * sysdeps/i386/dl-runtime.c (_dl_runtime_resolve): Pass new arg to _dl_lookup_symbol. * elf/do-rel.h (elf_dynamic_do_rel): Pass new second arg of R->r_offset to RESOLVE callback. * elf/dl-reloc.c (_dl_relocate_object: resolve): Don't let *REF satisfy the reference itself if its value equals the reloc's offset. * elf/rtld.c (dl_main): Write a newline in fatal msg. * Makerules (lib%.so: lib%_pic.a): Pass $(LDFLAGS.so).
127 lines
3.8 KiB
C
127 lines
3.8 KiB
C
/* Relocate a shared object and resolve its references to other loaded objects.
|
|
Copyright (C) 1995 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#include <link.h>
|
|
#include <sys/types.h>
|
|
#include <sys/mman.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
#include "dynamic-link.h"
|
|
|
|
|
|
void
|
|
_dl_relocate_object (struct link_map *l, int lazy)
|
|
{
|
|
const size_t pagesize = getpagesize ();
|
|
|
|
if (l->l_relocated)
|
|
return;
|
|
|
|
if (l->l_info[DT_TEXTREL])
|
|
{
|
|
/* Bletch. We must make read-only segments writable
|
|
long enough to relocate them. */
|
|
const Elf32_Phdr *ph;
|
|
for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
|
|
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
|
|
{
|
|
caddr_t mapstart = ((caddr_t) l->l_addr +
|
|
(ph->p_vaddr & ~(pagesize - 1)));
|
|
caddr_t mapend = ((caddr_t) l->l_addr +
|
|
((ph->p_vaddr + ph->p_memsz + pagesize - 1)
|
|
& ~(pagesize - 1)));
|
|
if (mprotect (mapstart, mapend - mapstart,
|
|
PROT_READ|PROT_WRITE) < 0)
|
|
_dl_signal_error (errno, l->l_name,
|
|
"cannot make segment writable for relocation");
|
|
}
|
|
}
|
|
|
|
{
|
|
struct link_map *real_next, *scope;
|
|
|
|
const char *strtab
|
|
= ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
|
|
|
|
|
|
Elf32_Addr resolve (const Elf32_Sym **ref, Elf32_Addr r_offset)
|
|
{
|
|
return _dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope,
|
|
l->l_name, (*ref)->st_value == r_offset);
|
|
}
|
|
|
|
real_next = l->l_next;
|
|
if (l->l_info[DT_SYMBOLIC])
|
|
{
|
|
if (l->l_prev)
|
|
l->l_prev->l_next = real_next;
|
|
l->l_next = _dl_loaded;
|
|
scope = l;
|
|
}
|
|
else
|
|
scope = _dl_loaded;
|
|
|
|
if (l->l_type == lt_interpreter)
|
|
/* We cannot be lazy when relocating the dynamic linker itself. It
|
|
was previously relocated eagerly (allowing us to be running now),
|
|
and needs always to be fully relocated so it can run without the
|
|
aid of run-time fixups (because it's the one to do them), so we
|
|
must always re-relocate its PLT eagerly. */
|
|
lazy = 0;
|
|
|
|
ELF_DYNAMIC_RELOCATE (l, lazy, resolve);
|
|
|
|
/* Restore list frobnication done above for DT_SYMBOLIC. */
|
|
l->l_next = real_next;
|
|
if (l->l_prev)
|
|
l->l_prev->l_next = l;
|
|
}
|
|
|
|
if (l->l_info[DT_JMPREL] && lazy)
|
|
/* Set up the PLT so its unrelocated entries will
|
|
jump to _dl_runtime_resolve, which will relocate them. */
|
|
elf_machine_runtime_setup (l);
|
|
|
|
l->l_relocated = 1;
|
|
|
|
if (l->l_info[DT_TEXTREL])
|
|
{
|
|
/* Undo the protection change we made before relocating. */
|
|
const Elf32_Phdr *ph;
|
|
for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
|
|
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
|
|
{
|
|
caddr_t mapstart = ((caddr_t) l->l_addr +
|
|
(ph->p_vaddr & ~(pagesize - 1)));
|
|
caddr_t mapend = ((caddr_t) l->l_addr +
|
|
((ph->p_vaddr + ph->p_memsz + pagesize - 1)
|
|
& ~(pagesize - 1)));
|
|
int prot = 0;
|
|
if (ph->p_flags & PF_R)
|
|
prot |= PROT_READ;
|
|
if (ph->p_flags & PF_X)
|
|
prot |= PROT_EXEC;
|
|
if (mprotect (mapstart, mapend - mapstart, prot) < 0)
|
|
_dl_signal_error (errno, l->l_name,
|
|
"can't restore segment prot after reloc");
|
|
}
|
|
}
|
|
|
|
}
|