/* Return section header.
Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2007 Red Hat, Inc.
This file is part of Red Hat elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 1998.
Red Hat elfutils is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by the
Free Software Foundation; version 2 of the License.
Red Hat elfutils 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
General Public License for more details.
You should have received a copy of the GNU General Public License along
with Red Hat elfutils; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
In addition, as a special exception, Red Hat, Inc. gives You the
additional right to link the code of Red Hat elfutils with code licensed
under any Open Source Initiative certified open source license
(http://www.opensource.org/licenses/index.php) which requires the
distribution of source code with any binary distribution and to
distribute linked combinations of the two. Non-GPL Code permitted under
this exception must only link to the code of Red Hat elfutils through
those well defined interfaces identified in the file named EXCEPTION
found in the source code files (the "Approved Interfaces"). The files
of Non-GPL Code may instantiate templates or use macros or inline
functions from the Approved Interfaces without causing the resulting
work to be covered by the GNU General Public License. Only Red Hat,
Inc. may make changes or additions to the list of Approved Interfaces.
Red Hat's grant of this exception is conditioned upon your not adding
any new exceptions. If you wish to add a new Approved Interface or
exception, please contact Red Hat. You must obey the GNU General Public
License in all respects for all of the Red Hat elfutils code and other
code used in conjunction with Red Hat elfutils except the Non-GPL Code
covered by this exception. If you modify this file, you may extend this
exception to your version of the file, but you are not obligated to do
so. If you do not wish to provide this exception without modification,
you must delete this exception statement from your version and license
this file solely under the GPL without exception.
Red Hat elfutils is an included package of the Open Invention Network.
An included package of the Open Invention Network is a package for which
Open Invention Network licensees cross-license their patents. No patent
license is granted, either expressly or impliedly, by designation as an
included package. Should you wish to participate in the Open Invention
Network licensing program, please visit www.openinventionnetwork.com
<http://www.openinventionnetwork.com>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <unistd.h>
#include <system.h>
#include "libelfP.h"
#include "common.h"
#ifndef LIBELFBITS
# define LIBELFBITS 32
#endif
static ElfW2(LIBELFBITS,Shdr) *
load_shdr_wrlock (Elf_Scn *scn)
{
ElfW2(LIBELFBITS,Shdr) *result;
/* Read the section header table. */
Elf *elf = scn->elf;
ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr;
/* Try again, maybe the data is there now. */
result = scn->shdr.ELFW(e,LIBELFBITS);
if (result != NULL)
goto out;
size_t shnum;
if (__elf_getshnum_rdlock (elf, &shnum) != 0)
goto out;
size_t size = shnum * sizeof (ElfW2(LIBELFBITS,Shdr));
/* Allocate memory for the section headers. We know the number
of entries from the ELF header. */
ElfW2(LIBELFBITS,Shdr) *shdr = elf->state.ELFW(elf,LIBELFBITS).shdr =
(ElfW2(LIBELFBITS,Shdr) *) malloc (size);
if (elf->state.ELFW(elf,LIBELFBITS).shdr == NULL)
{
__libelf_seterrno (ELF_E_NOMEM);
goto out;
}
elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 1;
if (elf->map_address != NULL)
{
ElfW2(LIBELFBITS,Shdr) *notcvt;
/* All the data is already mapped. If we could use it
directly this would already have happened. */
void *file_shdr = ((char *) elf->map_address
+ elf->start_offset + ehdr->e_shoff);
assert (ehdr->e_ident[EI_DATA] != MY_ELFDATA
|| (! ALLOW_UNALIGNED
&& ((uintptr_t) file_shdr
& (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1)) != 0));
/* Now copy the data and at the same time convert the byte order. */
if (ehdr->e_ident[EI_DATA] == MY_ELFDATA)
{
assert (! ALLOW_UNALIGNED);
memcpy (shdr, file_shdr, size);
}
else
{
if (ALLOW_UNALIGNED
|| ((uintptr_t) file_shdr
& (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1)) == 0)
notcvt = (ElfW2(LIBELFBITS,Shdr) *)
((char *) elf->map_address
+ elf->start_offset + ehdr->e_shoff);
else
{
notcvt = (ElfW2(LIBELFBITS,Shdr) *) alloca (size);
memcpy (notcvt, ((char *) elf->map_address
+ elf->start_offset + ehdr->e_shoff),
size);
}
for (size_t cnt = 0; cnt < shnum; ++cnt)
{
CONVERT_TO (shdr[cnt].sh_name, notcvt[cnt].sh_name);
CONVERT_TO (shdr[cnt].sh_type, notcvt[cnt].sh_type);
CONVERT_TO (shdr[cnt].sh_flags, notcvt[cnt].sh_flags);
CONVERT_TO (shdr[cnt].sh_addr, notcvt[cnt].sh_addr);
CONVERT_TO (shdr[cnt].sh_offset, notcvt[cnt].sh_offset);
CONVERT_TO (shdr[cnt].sh_size, notcvt[cnt].sh_size);
CONVERT_TO (shdr[cnt].sh_link, notcvt[cnt].sh_link);
CONVERT_TO (shdr[cnt].sh_info, notcvt[cnt].sh_info);
CONVERT_TO (shdr[cnt].sh_addralign,
notcvt[cnt].sh_addralign);
CONVERT_TO (shdr[cnt].sh_entsize, notcvt[cnt].sh_entsize);
/* If this is a section with an extended index add a
reference in the section which uses the extended
index. */
if (shdr[cnt].sh_type == SHT_SYMTAB_SHNDX
&& shdr[cnt].sh_link < shnum)
elf->state.ELFW(elf,LIBELFBITS).scns.data[shdr[cnt].sh_link].shndx_index
= cnt;
/* Set the own shndx_index field in case it has not yet
been set. */
if (elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index == 0)
elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index
= -1;
}
}
}
else if (likely (elf->fildes != -1))
{
/* Read the header. */
ssize_t n = pread_retry (elf->fildes,
elf->state.ELFW(elf,LIBELFBITS).shdr, size,
elf->start_offset + ehdr->e_shoff);
if (unlikely ((size_t) n != size))
{
/* Severe problems. We cannot read the data. */
__libelf_seterrno (ELF_E_READ_ERROR);
goto free_and_out;
}
/* If the byte order of the file is not the same as the one
of the host convert the data now. */
if (ehdr->e_ident[EI_DATA] != MY_ELFDATA)
for (size_t cnt = 0; cnt < shnum; ++cnt)
{
CONVERT (shdr[cnt].sh_name);
CONVERT (shdr[cnt].sh_type);
CONVERT (shdr[cnt].sh_flags);
CONVERT (shdr[cnt].sh_addr);
CONVERT (shdr[cnt].sh_offset);
CONVERT (shdr[cnt].sh_size);
CONVERT (shdr[cnt].sh_link);
CONVERT (shdr[cnt].sh_info);
CONVERT (shdr[cnt].sh_addralign);
CONVERT (shdr[cnt].sh_entsize);
}
}
else
{
/* The file descriptor was already enabled and not all data was
read. Undo the allocation. */
__libelf_seterrno (ELF_E_FD_DISABLED);
free_and_out:
free (shdr);
elf->state.ELFW(elf,LIBELFBITS).shdr = NULL;
elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 0;
goto out;
}
/* Set the pointers in the `scn's. */
for (size_t cnt = 0; cnt < shnum; ++cnt)
elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shdr.ELFW(e,LIBELFBITS)
= &elf->state.ELFW(elf,LIBELFBITS).shdr[cnt];
result = scn->shdr.ELFW(e,LIBELFBITS);
assert (result != NULL);
out:
return result;
}
static bool
scn_valid (Elf_Scn *scn)
{
if (scn == NULL)
return false;
if (unlikely (scn->elf->state.elf.ehdr == NULL))
{
__libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
return false;
}
if (unlikely (scn->elf->class != ELFW(ELFCLASS,LIBELFBITS)))
{
__libelf_seterrno (ELF_E_INVALID_CLASS);
return false;
}
return true;
}
ElfW2(LIBELFBITS,Shdr) *
__elfw2(LIBELFBITS,getshdr_rdlock) (scn)
Elf_Scn *scn;
{
ElfW2(LIBELFBITS,Shdr) *result;
if (!scn_valid (scn))
return NULL;
result = scn->shdr.ELFW(e,LIBELFBITS);
if (result == NULL)
{
rwlock_unlock (scn->elf->lock);
rwlock_wrlock (scn->elf->lock);
result = scn->shdr.ELFW(e,LIBELFBITS);
if (result == NULL)
result = load_shdr_wrlock (scn);
}
return result;
}
ElfW2(LIBELFBITS,Shdr) *
__elfw2(LIBELFBITS,getshdr_wrlock) (scn)
Elf_Scn *scn;
{
ElfW2(LIBELFBITS,Shdr) *result;
if (!scn_valid (scn))
return NULL;
result = scn->shdr.ELFW(e,LIBELFBITS);
if (result == NULL)
result = load_shdr_wrlock (scn);
return result;
}
ElfW2(LIBELFBITS,Shdr) *
elfw2(LIBELFBITS,getshdr) (scn)
Elf_Scn *scn;
{
ElfW2(LIBELFBITS,Shdr) *result;
if (!scn_valid (scn))
return NULL;
rwlock_rdlock (scn->elf->lock);
result = __elfw2(LIBELFBITS,getshdr_rdlock) (scn);
rwlock_unlock (scn->elf->lock);
return result;
}