/* Copyright (C) 2012 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 the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <sys/types.h>

#include <sys/stat.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

#include <gelf.h>

#include <libelf.h>

#include <stdbool.h>

#include <inttypes.h>

int

main (int argc, char *argv[])

{

  if (argc != 3)

    {

      fprintf (stderr, "Needs two arguments.\n");

      fprintf (stderr, "First needs to be 'READ', 'MMAP' or 'FDREAD'\n");

      fprintf (stderr, "Second is the ELF file to read.\n");

      exit (2); /* user error */

    }

  bool do_mmap = false;

  bool close_fd = false;

  if (strcmp (argv[1], "READ") == 0)

    {

      do_mmap = false;

      close_fd = false;

    }

  else if (strcmp (argv[1], "MMAP") == 0)

    {

      do_mmap = true;

      close_fd = false;

    }

  else if  (strcmp (argv[1], "FDREAD") == 0)

    {

      do_mmap = false;

      close_fd = true;

    }

  else

    {

      fprintf (stderr, "First arg needs to be 'READ', 'MMAP' or 'FDREAD'\n");

      exit (2); /* user error */

    }

  elf_version (EV_CURRENT);

  int fd = open (argv[2], O_RDONLY);

  if (fd < 0)

    {

      fprintf (stderr, "Cannot open input file %s: %s\n", argv[2],

	       strerror (errno));

      exit (2);

    }

  Elf *elf = elf_begin (fd, do_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);

  if (elf == NULL)

    {

      fprintf (stderr, "elf_begin failed for %s: %s\n", argv[2],

	       elf_errmsg (-1));

      exit (2);

    }

  if (! do_mmap && close_fd)

    {

      if (elf_cntl (elf, ELF_C_FDREAD) < 0)

	{

	  fprintf (stderr, "elf_cntl failed for %s: %s\n", argv[2],

		   elf_errmsg (-1));

	  exit (1);

	}

      close (fd);

    }

  Elf_Scn *scn = NULL;

  while ((scn = elf_nextscn (elf, scn)) != NULL)

    {

      GElf_Shdr shdr_mem;

      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);

      printf ("Section at offset %#0" PRIx64 "\n", shdr->sh_offset);

    }

  elf_end (elf);

  exit (0);

}