ec2

#!/bin/sh

VERBOSITY=1
TEMP_D=""
CONFIG=/etc/cirros-init/ds-ec2
MDURL="http://169.254.169.254/2009-04-04"
NAME="${0##*/}"

. ${CIRROS_SHLIB:=/lib/cirros/shlib} ||
	{ echo "failed to read ${CIRROS_SHLIB}" 1>&2; exit 1; }

error() { echo "$@" 1>&2; }
fail() { [ $# -eq 0 ] || error "$@"; exit 1; }

Usage() {
	cat <<EOF
Usage: ${0##*/} mode output_d

   Datasource for EC2 metadata service
   Requires network.
EOF
}

mdget() {
	ec2metadata "--url=$MDURL" "$@"
}

cleanup() {
	[ -z "${TMPF}" -o ! -f "$TMPF" ] || rm -f "${TMPF}"
}

search_local() {
	local out_d="$1"
	local i="" max="" iid="" uptime=""
	[ -d "$out_d" ] || mkdir -p "$out_d" ||
		{ error "failed to create output dir"; return 1; }
	TMPF="${out_d}/tmpf"

	trap cleanup EXIT

	debug 1 "checking $MDURL/instance-id"
	i=0
	MAX_TRIES=${MAX_TRIES:-20}
	SLEEP_TIME=${SLEEP_TIME:-2}

	max=${MAX_TRIES}
	while [ $i -lt ${max} ] && i=$(($i+1)); do
		read uptime idle < /proc/uptime
		if iid=$(mdget --instance-id 2>/dev/null); then
			[ "${iid#i-}" != "${iid}" ] && break
			debug 1 "failed $i/${max}: up ${uptime}. iid had '${iid}'"
		else
			debug 1 "failed $i/${max}: up ${uptime}. request failed"
		fi
		sleep $SLEEP_TIME
	done

	if [ -n "${iid}" ]; then
		debug 1 "successful after ${i}/${max} tries: up ${uptime}. iid=${iid}"
	else
		error "failed to read iid from metadata. tried ${max}";
		return 0
	fi

	local keys="" key=""
	keys="public-keys instance-id ami-launch-index instance-type local-ipv4
  		public-ipv4 hostname local-hostname user-data
  		block-device-mappings public-hostname availability-zone"
	mkdir -p "${out_d}/data"
	for key in $keys; do
		mdget "--${key}" > "${out_d}/data/${key}" ||
			debug 1 "warning: no ec2 metadata for $key"
	done

	local fix="" t="" f=""
	for fix in ami-launch-index:launch-index; do
		f="${fix%:*}"
		t="${fix#*:}"
		[ -f "${out_d}/data/$f" -a ! -f "${out_d}/data/$t" ] || continue
		ln -sf "$f" "${out_d}/data/$t" ||
			fail "failed to link $f to ${out_d}/data/t"
	done

	echo 0 > "$out_d/result"
	return
}

apply() {
	# ec2 datasource does nothing for apply
	local mode="$1" data_d="$2"
	return 0
}

short_opts="hv"
long_opts="help,verbose"
getopt_out=$(getopt --name "${0##*/}" \
	--options "${short_opts}" --long "${long_opts}" -- "$@") &&
	eval set -- "${getopt_out}" ||
	bad_Usage

output=""

while [ $# -ne 0 ]; do
	cur=${1}; next=${2};
	case "$cur" in
		-h|--help) Usage ; exit 0;;
		-v|--verbose) VERBOSITY=$((${VERBOSITY}+1));;
		--) shift; break;;
	esac
	shift;
done

[ $# -eq 2 ] || bad_Usage "must provide mode and data dir"
mode="$1"
out_d="$2"

[ "$mode" = "net" -o "$mode" = "apply-net" ] || {
	debug 2 "only supported in mode 'net' or 'apply-net'";
	exit 0;
}

[ ! -e "$CONFIG" ] || . "$CONFIG" ||
	fail "failed to read $CONFIG"

if [ "$mode" = "net" ]; then
	search_local "$out_d"
elif [ "$mode" = "apply-net" ]; then
	apply "$mode" "$out_d"
else
	fail "error, unexpected input"
fi

exit
# vi: ts=4 noexpandtab