#!/usr/local/bin/perl
#
# Copyright (c) 1998 University of Utah and the Flux Group.
# All rights reserved.
# 
# This file is part of the Flux OSKit.  The OSKit is free software, also known
# as "open source;" you can redistribute it and/or modify it under the terms
# of the GNU General Public License (GPL), version 2, as published by the Free
# Software Foundation (FSF).  To explore alternate licensing terms, contact
# the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
# 
# The OSKit 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 GPL for more details.  You should have
# received a copy of the GPL along with the OSKit; see the file COPYING.  If
# not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
#

# This program extracts the original files from a BSD boot image
# It makes use of the objdump program corresponding to the linker
# used to create the image.  (so i386-mach-ld == i386-mach-objdump).
#
# If you want to override which objdump it uses, set your OBJDUMP
# environment variable to the proper version of objdump.
#
# It outputs its files in the current directory.  It _will_ overwrite
# existing files, so be careful.

if (!$ENV{"OBJDUMP"}) 
{
	$ld = "@LD@";
	if ($ENV{"LD"}) { $ld = $ENV{"LD"}; }
    
# This is ugly black magic to try to figure out the proper objdump to use.
# We use the same prefix that the linker has.  If the linker
# isn't <something>ld, this will fail.
    
	$ldprefix = $ld;
	$ldprefix =~ s/ld$//;
	$objdump = "$ldprefix" . "objdump";
} else {
	$objdump = $ENV{"OBJDUMP"};
}

$objdumpflags = "-x --demangle";
$offset = 1048576;   # 0x100000
$headerlength = 32;  # Files in the binary have a 32 byte descriptive header.

sub usage {
	print STDERR "usage:  unmkbsdimage <Imagename>\n";
	exit -1;
}

##
# Convert an address from hex to decimal,
# and subtract the offset
##

sub cvt {
	local($hexnum) = $_[0];
	local($decv) = hex($hexnum);
	return ($decv - $offset + $headerlength);
}

##
# Get down to work
##
$image = $ARGV[0];

if (!$image) {
	usage();
}

if (!( -f "$image")) {
	print STDERR "No such file $image\n";
	exit -1;
}

print "Beginning extraction of $image\n\n";

##
# Get the information we need out of objdump
##

open(OBJDUMP, "$objdump $objdumpflags $image|") ||
    die "could not open objdump: $!\n";

while (<OBJDUMP>)
{
	chomp;
	($addr, $flags, $loc, $a, $b, $c, $name) = split;
	$daddr = &cvt($addr);
	if ($name =~ /binary_([a-zA-Z0-9_]+)_start/) {
		$START{$1} = $daddr; 
#		print "Start of $1:  $daddr\n";
	}
	if ($name =~ /binary_([a-zA-Z0-9_]+)_end/) {
		$END{$1} = $daddr; 
#		print "End of $1:  $daddr\n";
	}
}

close(OBJDUMP);

##
# Now extract the data from the Image file
##

open(IMAGE, $image) || die "Could not open $image: $!\n";

@files = keys %START;
foreach $file (@files)
{
	$start = $START{$file};
	$end = $END{$file};
	$length = $end - $start;
	printf("Extracting $file\n");

    # Seek to the offset in the image, read the binary, and then write it out.

	seek IMAGE,$start,SEEK_SET;
	read(IMAGE, $objdata, $length);
	open(OUT, ">$file") || die "Could not write to $file: $!\n";
	syswrite(OUT, $objdata, $length);
	close(OUT);
}

close(IMAGE);