libelf/elf32_newehdr.c

/* Create new ELF header.
   Copyright (C) 1998, 1999, 2000, 2002 Red Hat, Inc.
   Written by Ulrich Drepper <drepper@redhat.com>, 1998.

   This program 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.

   This program 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 this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

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

#include <stdlib.h>
#include <string.h>

#include "libelfP.h"

#ifndef LIBELFBITS
# define LIBELFBITS 32
#endif


ElfW2(LIBELFBITS,Ehdr) *
elfw2(LIBELFBITS,newehdr) (elf)
     Elf *elf;
{
  ElfW2(LIBELFBITS,Ehdr) *result;

  if (elf == NULL)
    return NULL;

  if (unlikely (elf->kind != ELF_K_ELF))
    {
      __libelf_seterrno (ELF_E_INVALID_HANDLE);
      return NULL;
    }

  rwlock_wrlock (elf->lock);

  if (elf->class == 0)
    elf->class = ELFW(ELFCLASS,LIBELFBITS);
  else if (unlikely (elf->class != ELFW(ELFCLASS,LIBELFBITS)))
    {
      __libelf_seterrno (ELF_E_INVALID_CLASS);
      result = NULL;
      goto out;
    }

  /* Don't create an ELF header if one already exists.  */
  if (elf->state.ELFW(elf,LIBELFBITS).ehdr == NULL)
    {
      /* We use the memory in the ELF descriptor.  */
      elf->state.ELFW(elf,LIBELFBITS).ehdr =
	&elf->state.ELFW(elf,LIBELFBITS).ehdr_mem;

      /* We clear this memory.  */
      memset (elf->state.ELFW(elf,LIBELFBITS).ehdr, '\0',
	      sizeof (ElfW2(LIBELFBITS,Ehdr)));

      /* Mark the ELF header has modified.  */
      elf->state.ELFW(elf,LIBELFBITS).ehdr_flags |= ELF_F_DIRTY;
    }

  result = elf->state.ELFW(elf,LIBELFBITS).ehdr;

 out:
  rwlock_unlock (elf->lock);

  return result;
}
INTDEF(elfw2(LIBELFBITS,newehdr))