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/* 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)
{
return _dl_lookup_symbol (strtab + (*ref)->st_name, ref, scope,
l->l_name);
}
real_next = l->l_next;
if (l->l_info[DT_SYMBOLIC])
{
l->l_prev->l_next = real_next;
l->l_next = _dl_loaded;
scope = l;
}
else
scope = _dl_loaded;
ELF_DYNAMIC_RELOCATE (l, lazy, resolve);
/* Restore list frobnication done above for DT_SYMBOLIC. */
l->l_next = real_next;
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");
}
}
}
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