#!/usr/bin/env bash
# script for use with xinetd to monitor readonly filesystem
#
# xinetd config
# service fsro
#{
#	disable = no
#	flags = REUSE
#	socket_type = stream
#	type = UNLISTED
#	port = 3333
#	wait = no
#	user = nobody
#	server = /usr/local/sbin/mount-ro-xinetd.sh
#	log_on_failure += USERID
#	only_from = 127.0.0.0/8
#}
#

function check_ok() {
	MSG="$1 healthy"
	LEN=$((${#MSG} + 2))
        echo -en "HTTP/1.1 200 OK\r\n"
        echo -en "Content-Type: text/plain\r\n"
        echo -en "Connection: close\r\n"
        echo -en "Content-Length: $LEN\r\n"
        echo -en "\r\n"
        echo -en "$MSG\r\n"
        sleep 0.1
        exit 0
}

function check_fail() {
	MSG="$1"
	LEN=$((${#MSG} + 2))
        echo -en "HTTP/1.1 503 Service Unavailable\r\n"
        echo -en "Content-Type: text/plain\r\n"
        echo -en "Connection: close\r\n"
        echo -en "Content-Length: $LEN\r\n"
        echo -en "\r\n"
        echo -en "$MSG\r\n"
        sleep 0.1
        exit 1
}

CHECK_PATH=/tmp
grep -q $CHECK_PATH /proc/mounts || check_fail "Mount missing: $CHECK_PATH"
dd if=/dev/urandom of=$CHECK_PATH/.test01 bs=1M count=10 status=none || check_fail "Write failed: $CHECK_PATH"
dd if=$CHECK_PATH/.test01 of=/dev/null bs=1M status=none || check_fail "Read failed: $CHECK_PATH"
check_ok "$CHECK_PATH"