98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/* Relocate a shared object and resolve its references to other loaded objects.
|
|
Copyright (C) 1995, 1996 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, struct link_map *scope[], int lazy)
|
|
{
|
|
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 ElfW(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 & ~(_dl_pagesize - 1)));
|
|
caddr_t mapend = ((caddr_t) l->l_addr +
|
|
((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
|
|
& ~(_dl_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");
|
|
}
|
|
}
|
|
|
|
{
|
|
/* Do the actual relocation of the object's GOT and other data. */
|
|
|
|
const char *strtab /* String table object symbols. */
|
|
= ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
|
|
|
|
/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
|
|
#define RESOLVE(ref, reloc_addr, noplt) \
|
|
(_dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope, \
|
|
l->l_name, reloc_addr, noplt))
|
|
|
|
#include "dynamic-link.h"
|
|
ELF_DYNAMIC_RELOCATE (l, lazy);
|
|
}
|
|
|
|
/* Set up the PLT so its unrelocated entries will jump to
|
|
_dl_runtime_resolve (dl-runtime.c), which will relocate them. */
|
|
elf_machine_runtime_setup (l, lazy);
|
|
|
|
/* Mark the object so we know ths work has been done. */
|
|
l->l_relocated = 1;
|
|
|
|
if (l->l_info[DT_TEXTREL])
|
|
{
|
|
/* Undo the protection change we made before relocating. */
|
|
const ElfW(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 & ~(_dl_pagesize - 1)));
|
|
caddr_t mapend = ((caddr_t) l->l_addr +
|
|
((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
|
|
& ~(_dl_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");
|
|
}
|
|
}
|
|
}
|