#!/bin/sh
#
# Copyright (c) 1994-1999 The University of Utah and the Flux Group.
#
# This file is part of the OSKit Linux Boot Loader, which is free software;
# 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).
# 
# 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, USA.
#

# This little script uses GNU ld to build a Linux 16-bit compressed boot image
# from a set of boot modules.

#
# Usage: mklinuximage [options] [files ...]
#
# Options:
#   -o filename
#      Specify the output <filename> of the resulting Linux image. The
#      default is "zImage" in the current directory.
#   -stdin
#      Take file specifications from stdin, in addition to those on the
#      command line. This is useful when using another script to build
#      a list of file specifications which can then be piped into this
#      script.
#   -save-temps
#      Debugging option to save temporary files instead of deleting them
#      after the image is built.
#   [files ...]
#      A list of file specifications in the format pathname1:pathname2,
#      where pathname1 is the name of a local module which is placed in the
#      boot image. If :pathname2 is provided, it specifies the name to give
#      the module in the image. If :pathname2 is omitted, it defaults to
#      pathname1.
#
#   The first file specification is typically the name of the Oskit kernel.
#

bootdir=${BOOTDIR-@prefix@/lib/oskit}
as=${as-@as@}
ld=${LD-@LD@}

modules=
outfile=zImage
savetemps=

# Parse the command-line options.
until [ $# -eq 0 ]
do
	case "$1" in
		-o ) outfile="$2"; shift; shift;;
		-stdin) fromstdin="yes"; shift;;
		-save-temps) savetemps="$1"; shift;;
		* ) modules="$modules $1"; shift;;
	esac
done

#
# Read the rest of the modules from stdin.
#
if [ "X${fromstdin}" != "X" ]; then
	read mod
	while [ "X${mod}" != "X" ];
	do
		modules="$modules $mod"
		read mod
	done
fi

# Wrap each of the input files in a .o file.
# At the same time, build an assembly language module
# containing a table describing the boot modules.
echo >$outfile.mods.S ".text; .long 0xf00baabb"
files=
for module in $modules; do
	# Split out the associated string, if any.
	file=`echo $module | sed -e 's,:.*$,,'`
	string=`echo $module | sed -e 's,^[^:]*:,,'`
	if test -z "$string"; then string=$file; fi

	# Add this file to the list of files to be included,
	# but only if it hasn't already been seen before
	# (e.g., with a different attached string).
	alreadythere=
	for afile in $files; do
		if [ $file = $afile ]; then alreadythere=yes; fi
	done
	if [ -z $alreadythere ]; then files="$files $file"; fi

	# Convert all non-alphanumeric chars to underscores.
	# The BFD binary input format will do the same thing
	# to produce the symbol names that it "wraps around" the input files.
	sym_name=`echo $module | sed -e 's,[^a-zA-Z0-9],_,g'`
	echo >>$outfile.mods.S ".long _binary_$sym_name""_start"
	echo >>$outfile.mods.S ".long _binary_$sym_name""_end"
	echo >>$outfile.mods.S ".long cmdline_$sym_name"
	echo >>$outfile.mods.S ".data"
	echo >>$outfile.mods.S "cmdline_$sym_name: .ascii \"$string\\0\""
	echo >>$outfile.mods.S ".text"
done
echo >>$outfile.mods.S ".long 0; .data; .align 4"

# Assemble the module vector file.
$as -c -o $outfile.mods.o $outfile.mods.S || exit 1

# Link the module vector file with the boot module files.
# Use the binary bfd backend for both the input bmod files and the output file.
# There is no meaning to "entry point address" in the binary backend,
# but the linker doesn't know that, so it looks for _start and warns
# when it doesn't find it (and falls back to zero).  To stifle the warning
# we can define the `_start' symbol on the command line; I think this
# works with all GNU ld versions.
$ld -Ttext 0 -defsym _start=0 -oformat binary -o $outfile.tmp \
	$outfile.mods.o -format binary $files -format default \
	|| exit 1

# Compress the whole output file as one big glob.
gzip -9 <$outfile.tmp >$outfile.tmp.gz

# Create the final boot image by tacking that onto the end of 'linuxboot.bin'.
cat $bootdir/linuxboot.bin $outfile.tmp.gz >$outfile

if test -z "$savetemps"; then
	rm -f $outfile.mods.S $outfile.mods.o $outfile.tmp $outfile.tmp.gz
fi

exit 0