libelf/gelf_getverneed.c

/* Get required symbol version information at the given offset.
   Copyright (C) 1999, 2000, 2001, 2002 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 1999.

   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
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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
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#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

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

#include "libelfP.h"


GElf_Verneed *
gelf_getverneed (data, offset, dst)
     Elf_Data *data;
     int offset;
     GElf_Verneed *dst;
{
  GElf_Verneed *result;

  if (data == NULL)
    return NULL;

  if (unlikely (data->d_type != ELF_T_VNEED))
    {
      __libelf_seterrno (ELF_E_INVALID_HANDLE);
      return NULL;
    }

  /* It's easy to handle this type.  It has the same size for 32 and
     64 bit objects.  And fortunately the `ElfXXX_Vernaux' records
     also have the same size.  */
  assert (sizeof (GElf_Verneed) == sizeof (Elf32_Verneed));
  assert (sizeof (GElf_Verneed) == sizeof (Elf64_Verneed));
  assert (sizeof (GElf_Verneed) == sizeof (Elf32_Vernaux));
  assert (sizeof (GElf_Verneed) == sizeof (Elf64_Vernaux));

  rwlock_rdlock (((Elf_Data_Scn *) data)->s->elf->lock);

  /* The data is already in the correct form.  Just make sure the
     index is OK.  */
  if (unlikely (offset < 0)
      || unlikely (offset + sizeof (GElf_Verneed) > data->d_size)
      || unlikely (offset % sizeof (GElf_Verneed) != 0))
    {
      __libelf_seterrno (ELF_E_OFFSET_RANGE);
      result = NULL;
    }
  else
    result = (GElf_Verneed *) memcpy (dst, (char *) data->d_buf + offset,
				      sizeof (GElf_Verneed));

  rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock);

  return result;
}