#!/bin/sh
### BEGIN INIT INFO
# Provides:          atari800_binfmt_misc
# Required-Start:    
# Required-Stop:     
# Default-Start:     2 3 4 5
# Default-Stop:
# Short-Description: Register Atari 8-bit file formats with binfmt_misc
### END INIT INFO

# atari800_binfmt_misc: register Atari 8-bit file formats with binfmt_misc.
# Allows direct execution of Atari executables, disk images, boot cassette
# images, BASIC programs, and cartridge images, via the atari800 emulator.

PROCDIR=/proc/sys/fs/binfmt_misc
EMUDIRS="/usr/local/bin /usr/bin /bin"

### Functions. This script doesn't depend on any external function library.

die() {
	echo $1 1>&2
	exit 1
}

usage() {
	cat <<EOF
Usage: $0 stop | start | restart

This service registers Atari 8-bit file types with the kernel's binfmt_misc
driver, to allow users to directly execute Atari software (disk images,
executables, BASIC programs, boot cassette images, and cartridge images)
as though they were native Linux executables.

To run Atari software, the atari800 emulator is required. Normally, atari800
requires X to be running (it may be possible to compile it for console use).
Get atari800 from: http://atari800.sourceforge.net

If you get a "Can't find atari800 emulator" error, either install atari800
in one of these directories: $EMUDIRS

...or set ATARI800_BIN in the environment to the full path of the emulator
binary: export ATARI800_BIN=/opt/atari800/bin/atari800
EOF

	exit 1
}

find_atari800() {
	if [ -z "$ATARI800_BIN" ]; then
		ATARI800_BIN=none

		for path in $EMUDIRS; do
			if [ -x $path/atari800 ]; then
				ATARI800_BIN=$path/atari800
			fi
		done

		if [ "$ATARI800_BIN" = "none" ]; then
			die "Can't find atari800 emulator in $EMUDIRS"
		fi
	fi
}

init_binfmt_misc() {
	# Load/init binfmt_misc, if needed.
	/sbin/modprobe binfmt_misc 2>/dev/null
	mount -t binfmt_misc none $PROCDIR 2>/dev/null
}

check_binfmt_misc() {
	# sanity check
	cd $PROCDIR && [ -f status ]
	if [ "$?" != "0" ]; then
		die "binfmt_misc not available in kernel"
	fi
}

unregister_filetypes() {
	local type
	cd $PROCDIR || die "$PROCDIR does not exist"

	# Unregister filetypes, if already registered
	# (not an error if already unregistered)
	for type in \
		atari8_xex atari8_basic atari8_atr \
		atari8_xfd atari8_Xfd atari8_XFD \
		atari8_cas atari8_cart
	do
		[ -f $type ] && echo -1 > $type
	done
}

register_filetypes() {
	cd $PROCDIR || die "$PROCDIR does not exist"

	# Register filetypes
	# :name:type:offset:magic:mask:interpreter:flags
	# see /usr/src/linux/Documentation/binfmt_misc.txt or
	# http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html
	# for explanation of this.
	echo ':atari8_xex:M::\xff\xff::'$ATARI800_BIN':' > register
	echo ':atari8_basic:M::\x00\x00::'$ATARI800_BIN':' > register
	echo ':atari8_atr:M::\x96\x02::'$ATARI800_BIN':' > register
	echo ':atari8_xfd:E::xfd::'$ATARI800_BIN':' > register
	echo ':atari8_Xfd:E::Xfd::'$ATARI800_BIN':' > register
	echo ':atari8_XFD:E::XFD::'$ATARI800_BIN':' > register
	echo ':atari8_cas:M::FUJI::'$ATARI800_BIN':' > register
	echo ':atari8_cart:M::CART::'$ATARI800_BIN':' > register

	# This is disabled because (a) lots of emulators use .rom files, and
	# (b) current version of atari800 needs the -cart parameter for raw
	# ROM dumps, which we can't provide via binfmt_misc.
	#echo ':atari8_rom:E::rom::'$ATARI800_BIN':' > register

	# see if it worked:
	if [ ! -f atari8_xex ]; then
		die "Failed to register filetypes, are you root?"
	fi
}

### main()
case "$1" in
	stop)
		unregister_filetypes
		;;

	start)
		init_binfmt_misc
		check_binfmt_misc
		find_atari800
		register_filetypes
		;;

	restart)
		init_binfmt_misc
		check_binfmt_misc
		unregister_filetypes
		find_atari800
		register_filetypes
		;;

	*)
		usage
		;;

esac

exit 0

# notes:

# NO parameters allowed when calling the emulator, use a wrapper
# script if you need to always pass e.g. -windowed or -ntscemu, or
# just put on the command line when you run an Atari program.

# there's no "magic" for recognizing XFD images. Instead, they're
# recognized by filename extension... which is case-sensitive, hence
# the xfd/Xfd/XFD combination. Feel free to add xFD or xFd, etc, if
# you have a bunch of files named like that (better solution would be
# to rename them!)

# There's no way to determine whether a given disk or tape image
# requires BASIC. The wrapper scripts assume that a boot disk, XEX
# file, or boot tape, does not require BASIC... and that a BASIC
# program (obviously) does. Unfortunately there's no easy way to
# have the emulator run CLOAD, for a non-bootable BASIC tape, so
# CAS support can only work with boot tapes.

# Likewise, there's no way to tell whether a given tape or disk
# image is in fact bootable (well, not really true, the wrappers
# *could* examine boot records, etc, but they don't).

# If you have a XEX, ATR/XFD image, or boot CAS image that requires
# BASIC, you can enable it, by adding the -basic parameter to the
# command line (e.g. "myimage.atr -basic"). More generally, you
# can pass arbitrary atari800 options just by putting them on the
# image command line (see atari800 -help for full list).