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/* Relocate a shared object and resolve its references to other loaded objects.
Copyright (C) 1995, 1996, 1997, 1998, 1999 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., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <elf/ldsodefs.h>
#include <sys/mman.h>
#include <sys/types.h>
#include "dynamic-link.h"
void
_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
int lazy, int consider_profiling)
{
if (l->l_relocated)
return;
/* If DT_BIND_NOW is set relocate all references in this object. We
do not do this if we are profiling, of course. */
if (!consider_profiling && l->l_info[DT_BIND_NOW])
lazy = 0;
if (_dl_debug_reloc)
_dl_debug_message (1, "\nrelocation processing: ",
l->l_name[0] ? l->l_name : _dl_argv[0],
lazy ? " (lazy)\n" : "\n", NULL);
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. */
/* String table object symbols. */
const char *strtab = (const void *) 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, version, flags) \
((version) != NULL && (version)->hash != 0 \
? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, (ref), scope, \
l->l_name, (version), (flags)) \
: _dl_lookup_symbol (strtab + (*ref)->st_name, (ref), scope, \
l->l_name, (flags)))
#include "dynamic-link.h"
ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
if (_dl_profile != NULL)
{
/* Allocate the array which will contain the already found
relocations. */
l->l_reloc_result =
(ElfW(Addr) *) calloc (sizeof (ElfW(Addr)),
l->l_info[DT_PLTRELSZ]->d_un.d_val);
if (l->l_reloc_result == NULL)
_dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
"cannot allocate memory for profiling", NULL);
}
}
/* Mark the object so we know this 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)));
extern unsigned char _dl_pf_to_prot[8];
int prot;
if ((PF_R | PF_W | PF_X) == 7
&& (PROT_READ | PROT_WRITE | PROT_EXEC) == 7)
prot = _dl_pf_to_prot[ph->p_flags & (PF_R | PF_X)];
else
{
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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