libelf/gelf_getrela.c

/* Get RELA relocation information at given index.
   Copyright (C) 2000, 2001, 2002 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2000.

   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.

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   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.

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   additional right to link the code of Red Hat elfutils with code licensed
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   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
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   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
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#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <gelf.h>
#include <string.h>

#include "libelfP.h"


GElf_Rela *
gelf_getrela (data, ndx, dst)
     Elf_Data *data;
     int ndx;
     GElf_Rela *dst;
{
  Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
  Elf_Scn *scn;
  GElf_Rela *result;

  if (data_scn == NULL)
    return NULL;

  if (unlikely (ndx < 0))
    {
      __libelf_seterrno (ELF_E_INVALID_INDEX);
      return NULL;
    }

  if (unlikely (data_scn->d.d_type != ELF_T_RELA))
    {
      __libelf_seterrno (ELF_E_INVALID_HANDLE);
      return NULL;
    }

  /* This is the one place where we have to take advantage of the fact
     that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
     The interface is broken so that it requires this hack.  */
  scn = data_scn->s;

  rwlock_rdlock (scn->elf->lock);

  if (scn->elf->class == ELFCLASS32)
    {
      /* We have to convert the data.  */
      if (unlikely ((ndx + 1) * sizeof (Elf32_Rela) > data_scn->d.d_size))
	{
	  __libelf_seterrno (ELF_E_INVALID_INDEX);
	  result = NULL;
	}
      else
	{
	  Elf32_Rela *src = &((Elf32_Rela *) data_scn->d.d_buf)[ndx];

	  dst->r_offset = src->r_offset;
	  dst->r_info = GELF_R_INFO (ELF32_R_SYM (src->r_info),
				     ELF32_R_TYPE (src->r_info));
	  dst->r_addend = src->r_addend;

	  result = dst;
	}
    }
  else
    {
      /* Simply copy the data after we made sure we are actually getting
	 correct data.  */
      if (unlikely ((ndx + 1) * sizeof (Elf64_Rela) > data_scn->d.d_size))
	{
	  __libelf_seterrno (ELF_E_INVALID_INDEX);
	  result = NULL;
	}
      else
	result = memcpy (dst, &((Elf64_Rela *) data_scn->d.d_buf)[ndx],
			 sizeof (Elf64_Rela));
    }

  rwlock_unlock (scn->elf->lock);

  return result;
}