#!/bin/bash

CONFIG_FILE="/etc/suspend.conf"
RESUME="/usr/sbin/resume"

#
# Output usage on invalid arguments.
#
if [ ${#} -ne 1 ]; then
	echo -e "Usage:\n ${0} <outputfile>\n" 1>&2
	echo "Normally, one would do something like:" 1>&2
	echo -e " ${0} /boot/resume-initrd\n" 1>&2
	echo "Remember to set up your bootloader. Grub example:" 1>&2
	echo " title=Gentoo Linux 2.6.20-r8" 1>&2
	echo " root (hd0,0)" 1>&2
	echo " kernel /kernel-2.6.20-gentoo-r8 root=/dev/hdc3" 1>&2
	echo " initrd /resume-initrd" 1>&2
	exit 1
fi

#
# Valid outfile?
#
touch "${1}" || exit 1
OUTFILE="${1}"

#
# Make sure there is a config file.
#
if [ ! -f "${CONFIG_FILE}" ]; then
	echo "Error: Could not find config file at ${CONFIG_FILE}!" 1>&2
	exit 1
fi

#
# Get values from CONFIG_FILE
#
RESUME_DEVICE="$(cat "${CONFIG_FILE}" | sed -ne 's/^[ \t]*resume[ \t]\+device[ \t]*\=[ \t]*\([^ \t].*\)$/\1/p')"
INITRD_SIZE="$(cat "${CONFIG_FILE}" | sed -ne 's/^[ \t]*image[ \t]\+size[ \t]*\=[ \t]*\([^ \t].*\)$/\1/p')"

#
# Default value
#
if [ -z "${INITRD_SIZE}" ]; then
	INITRD_SIZE="2000k"
fi

#
# Validate variables
#
if [ ! -b ${RESUME_DEVICE} ]; then
 	echo "Error: Device ${RESUME_DEVICE} does not exist!" 1>&2
 	echo "Check your configuration (${CONFIG_FILE})." 1>&2
	exit 1
fi
if [ ! -f ${RESUME} ]; then
	RESUME="$(which resume 2> /dev/null)"
fi
if [ ! -f ${RESUME} ]; then
 	echo "Error: Could not find resume executable!" 1>&2
	exit 1
fi

#
# Create temporary files
#
TMP_FILE="$(mktemp -t initrd_dat.XXXXXX)"
MOUNT_POINT="$(mktemp -dt initrd_mnt.XXXXXX)"

#
# Create and mount image
#
dd if=/dev/zero of="${TMP_FILE}" bs="${INITRD_SIZE}" count=1
/sbin/mke2fs -F -m0 "${TMP_FILE}"
mount -t ext2 -o loop "${TMP_FILE}" "${MOUNT_POINT}"

#
# Copy contents to image
#
if [ "$?" = "0" ]; then 
	mkdir "${MOUNT_POINT}/dev"
	mkdir "${MOUNT_POINT}/proc"
	mkdir "${MOUNT_POINT}/etc"

	cp -R /dev/console       "${MOUNT_POINT}/dev/"
	cp -R /dev/snapshot      "${MOUNT_POINT}/dev/"
	cp -R /dev/random        "${MOUNT_POINT}/dev/"
	cp -R /dev/urandom       "${MOUNT_POINT}/dev/"
	cp -R "${RESUME_DEVICE}" "${MOUNT_POINT}/dev/"
	cp "${CONFIG_FILE}"      "${MOUNT_POINT}/etc/"
	cp "${RESUME}"           "${MOUNT_POINT}/resume"
	ln -s resume             "${MOUNT_POINT}/linuxrc"

#
# Copy result to OUTFILE.
#
	umount "${MOUNT_POINT}"
	if [ -s "${OUTFILE}" ]; then
		mv "${OUTFILE}" "${OUTFILE}.orig"
	fi
	chmod 644 "${TMP_FILE}"
	mv "${TMP_FILE}" "${OUTFILE}"

else
	echo "Error: Could not mount ${TMP_FILE} on ${MOUNT_POINT}!" 1>&2
fi

# Clean up
rmdir "${MOUNT_POINT}"

exit 0