/* Copyright (C) 1999, 2000, 2002 Red Hat, Inc.

   This file is part of elfutils.

   Written by Ulrich Drepper <drepper@redhat.com>, 1999.

   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 <fcntl.h>

#include <gelf.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <system.h>

int

main (int argc, char *argv[])

{

  int fd;

  Elf *elf;

  Elf *subelf;

  Elf_Cmd cmd;

  off_t offset;

  size_t todo;

  if (argc < 4)

    exit (1);

  /* Open the archive.  */

  fd = open (argv[1], O_RDONLY);

  if (fd == -1)

    {

      printf ("Cannot open input file: %m");

      exit (1);

    }

  /* Set the ELF version.  */

  elf_version (EV_CURRENT);

  /* Create an ELF descriptor.  */

  cmd = ELF_C_READ;

  elf = elf_begin (fd, cmd, NULL);

  if (elf == NULL)

    {

      printf ("Cannot create ELF descriptor: %s\n", elf_errmsg (-1));

      exit (1);

    }

  /* If it is no archive punt.  */

  if (elf_kind (elf) != ELF_K_AR)

    {

      printf ("`%s' is no archive\n", argv[1]);

      exit (1);

    }

  /* Get the elements of the archive one after the other.  */

  while ((subelf = elf_begin (fd, cmd, elf)) != NULL)

    {

      /* The the header for this element.  */

      Elf_Arhdr *arhdr = elf_getarhdr (subelf);

      if (arhdr == NULL)

	{

	  printf ("cannot get arhdr: %s\n", elf_errmsg (-1));

	  exit (1);

	}

      if (strcmp (arhdr->ar_name, argv[2]) == 0)

	{

	  int outfd;

	  /* Get the offset of the file in the archive.  */

	  offset = elf_getbase (subelf);

	  if (offset == -1)

	    {

	      printf ("\

Failed to get base address for the archive element: %s\n",

		      elf_errmsg (-1));

	      exit (1);

	    }

	  /* Open the output file.  */

	  outfd = open (argv[3], O_CREAT | O_TRUNC | O_RDWR, 0666);

	  if (outfd == -1)

	    {

	      printf ("cannot open output file: %m");

	      exit (1);

	    }

	  /* Now write out the data.  */

	  todo = arhdr->ar_size;

	  while (todo > 0)

	    {

	      char buf[1024];

	      ssize_t n = pread (fd, buf, MIN (sizeof buf, todo), offset);

	      if (n == 0)

		break;

	      if (write (outfd, buf, n) != n)

		{

		  puts ("Writing output failed");

		  exit (1);

		}

	      offset += n;

	      todo -= n;

	    }

	  /* Check whether all the date was read and written out.  */

	  if (todo != 0)

	    {

	      puts ("Reading archive member failed.");

	      exit (1);

	    }

	  /* Close the descriptors.  */

	  if (elf_end (subelf) != 0 || elf_end (elf) != 0)

	    {

	      printf ("Freeing ELF descriptors failed: %s", elf_errmsg (-1));

	      exit (1);

	    }

	  close (outfd);

	  close (fd);

	  /* All went well.  */

	  exit (0);

	}

      /* Get next archive element.  */

      cmd = elf_next (subelf);

      if (elf_end (subelf) != 0)

	{

	  printf ("error while freeing sub-ELF descriptor: %s\n",

		  elf_errmsg (-1));

	  exit (1);

	}

    }

  /* When we reach this point we haven't found the given file in the

     archive.  */

  printf ("File `%s' not found in archive\n", argv[2]);

  exit (1);

}