xref: /third_party/elfutils/backends/common-reloc.c

/* Common code for ebl reloc functions.
   Copyright (C) 2005, 2006 Red Hat, Inc.
   This file is part of elfutils.

   This file is free software; you can redistribute it and/or modify
   it under the terms of either

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at
       your option) any later version

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at
       your option) any later version

   or both in parallel, as here.

   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 copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see <http://www.gnu.org/licenses/>.  */

#include "libebl_CPU.h"
#include <assert.h>

#define R_TYPE(name)		PASTE (RELOC_PREFIX, name)
#define PASTE(a, b)		PASTE_1 (a, b)
#define PASTE_1(a, b)		a##b
#define R_NAME(name)		R_NAME_1 (RELOC_PREFIX, name)
#define R_NAME_1(prefix, type)	R_NAME_2 (prefix, type)
#define R_NAME_2(prefix, type)	#prefix #type

#define RELOC_TYPES		STRINGIFIED_PASTE (BACKEND, reloc.def)
#define STRINGIFIED_PASTE(a, b)	STRINGIFY (PASTE (a, b))
#define STRINGIFY(x)		STRINGIFY_1 (x)
#define STRINGIFY_1(x)		#x

/* Provide a table of reloc type names, in a PIC-friendly fashion.  */

static const struct EBLHOOK(reloc_nametable)
{
  char zero[1];
#define	RELOC_TYPE(type, uses) \
  char name_##type[sizeof R_NAME (type)];
#include RELOC_TYPES
#undef RELOC_TYPE
} EBLHOOK(reloc_nametable) =
  {
    { '\0' },
#define	RELOC_TYPE(type, uses) R_NAME (type),
#include RELOC_TYPES
#undef RELOC_TYPE
  };
#define reloc_namestr (&EBLHOOK(reloc_nametable).zero)

static const uint_fast16_t EBLHOOK(reloc_nameidx)[] =
{
#define	RELOC_TYPE(type, uses) \
  [R_TYPE (type)] = offsetof (struct EBLHOOK(reloc_nametable), name_##type),
#include RELOC_TYPES
#undef RELOC_TYPE
};
#define nreloc \
  ((int) (sizeof EBLHOOK(reloc_nameidx) / sizeof EBLHOOK(reloc_nameidx)[0]))

#define REL	(1 << (ET_REL - 1))
#define EXEC	(1 << (ET_EXEC - 1))
#define DYN	(1 << (ET_DYN - 1))
static const uint8_t EBLHOOK(reloc_valid)[] =
{
#define	RELOC_TYPE(type, uses) [R_TYPE (type)] = uses,
#include RELOC_TYPES
#undef RELOC_TYPE
};
#undef REL
#undef EXEC
#undef DYN

const char *
EBLHOOK(reloc_type_name) (int reloc,
			  char *buf __attribute__ ((unused)),
			  size_t len __attribute__ ((unused)))
{
#ifdef RELOC_TYPE_ID
  reloc = RELOC_TYPE_ID (reloc);
#endif

  if (reloc >= 0 && reloc < nreloc && EBLHOOK(reloc_nameidx)[reloc] != 0)
    return reloc_namestr[EBLHOOK(reloc_nameidx)[reloc]];
  return NULL;
}

bool
EBLHOOK(reloc_type_check) (int reloc)
{
#ifdef RELOC_TYPE_ID
  reloc = RELOC_TYPE_ID (reloc);
#endif

  return reloc >= 0 && reloc < nreloc && EBLHOOK(reloc_nameidx)[reloc] != 0;
}

bool
EBLHOOK(reloc_valid_use) (Elf *elf, int reloc)
{
  uint8_t uses;

  GElf_Ehdr ehdr_mem;
  GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
  assert (ehdr != NULL);
  uint8_t type = ehdr->e_type;

#ifdef RELOC_TYPE_ID
  reloc = RELOC_TYPE_ID (reloc);
#endif

  uses = EBLHOOK(reloc_valid)[reloc];
  return type > ET_NONE && type < ET_CORE && (uses & (1 << (type - 1)));
}

#ifndef NO_COPY_RELOC
bool
EBLHOOK(copy_reloc_p) (int reloc)
{
  return reloc == R_TYPE (COPY);
}
#endif

bool
EBLHOOK(none_reloc_p) (int reloc)
{
  return reloc == R_TYPE (NONE);
}

#ifndef NO_RELATIVE_RELOC
bool
EBLHOOK(relative_reloc_p) (int reloc)
{
  return reloc == R_TYPE (RELATIVE);
}
#endif

static void
EBLHOOK(init_reloc) (Ebl *ebl)
{
  ebl->reloc_type_name = EBLHOOK(reloc_type_name);
  ebl->reloc_type_check = EBLHOOK(reloc_type_check);
  ebl->reloc_valid_use = EBLHOOK(reloc_valid_use);
  ebl->none_reloc_p = EBLHOOK(none_reloc_p);
#ifndef NO_COPY_RELOC
  ebl->copy_reloc_p = EBLHOOK(copy_reloc_p);
#endif
#ifndef NO_RELATIVE_RELOC
  ebl->relative_reloc_p = EBLHOOK(relative_reloc_p);
#endif
}