mambrus/dyndns_update.sh

## dyndns_update.sh
#! /bin/bash
# This script updates a dynamic-DNS record for a specific NIC of your host.
# Script is made for freedns.afraid.org but should in principle work for
# other providers as well that allow DNS updates by simply loading a
# specific URL.
#
# Usage: dyndns_update.sh IF SHA1
#
# As this script is meant to be run from cron, it will be fairly silent,
# except when something goes wrong in an unexpected way or when a change of
# IP address actually occurred. (note, some of the fails are normal and not
# unexpected). To see the output of the log, export the environment variable
# LOGFILE to "--" (any other content of that variable will write to this
# file-name).
#
# Example: (export LOGFILE="--"; dyndns_update.sh eth1 $MYHOST)

IFNAME=${1}
SHA1=${2}
SHOST=${3-"freedns.afraid.org"}
SHELL=$(basename $0)

#Set export of this to "--" if you want output visible
LOGFILE=${LOGFILE-"/tmp/update_dyndns.log"}
source logger.sh
source pipe_logic.sh

if [ "X$IFNAME" == "X" ]; then
        logger "First argument (IFNAME) must be present. Exiting..."
        exit 1
fi

if [ "X$SHA1" == "X" ]; then
        logger "Second argument (SHA1) must be present. Exiting..."
        exit 1
fi

NIC_IPNR=$(ifconfig | \
        grep $IFNAME -A3 | \
        grep "inet addr" | \
        cut -f2 -d":" | \
        cut -f1 -d " ")
LNET=$(echo $NIC_IPNR | cut -f1-3 -d".").0
GW=$(echo $NIC_IPNR | cut -f1-3 -d".").1
URL="http://${SHOST}/dynamic/update.php?${SHA1}"

if [ "X$NIC_IPNR" == "X" ]; then
        logger "IF [$IFNAME] not up or doesn't exist. Exiting..."
        exit 1
fi

logger "$(basename $0): Updating dynamic DNS to interface: [$IFNAME]"
logger "   NIC: [$NIC_IPNR]"
logger "   NET: [$LNET]"
logger "    GW: [$GW]"
logger "   URL: [$URL]"
logger

# Try removing temporary route first, in case last invocation didn't complete.
route -v del -host $SHOST >/dev/null 2>&1

#set -e  #Trigger e-mail if something goes wrong from here on & if run in cron
logger "Setting temporary route for [$SHOST]"
route -v -A inet add -host $SHOST gw $GW | logger
#route -v -A inet add -host $SHOST gw $GW
netstat -anr | logger
#netstat -anr
logger "Updating dyn-DNS [$URL]"
RESPONSE=$(wget -O - $URL 2>/dev/null)
logger "Removing temporary route [$SHOST]"
route -v del -host $SHOST | logger
logger
logger "Response from service provider [$SHOST] for [$IFNAME]:"
logger "$RESPONSE"
set +e  #Stop trigger error mails (grep returns fail is not found)
if [ \
        "X$(echo $RESPONSE | grep 'has not changed')" == "X" -a \
        "X${LOGFILE}" != "X--" \
]; then
        # Something else is responded. Make it visable in syslog (if used from
        # cron), might be an error (or at least interesting).
        echo "Response from service provider [$SHOST] for [$IFNAME]:"
        echo "$RESPONSE"
fi

## logger.sh
#! /bin/bash
# Helper functions to make nice log-output to the right destination
#
# Format is a ":" separated list with each column meaning the following:
# 1) TS:      Time since epoc in nano-seconds. Numerical format makes it ideal
#             or sorting. Recover to human readable date by executing:
#             date -d "${TS}"
# 2) PPID:    Parent ID. Cront, init or your shell.
# 3) PID:     PID of the executing shell
#
# This file is meant to be sourced
if [ -z $LOGGER_SH ]; then
LOGGER_SH=logger.sh
source pipe_logic.sh

LOGFILE=${LOGFILE-"--"}

#Log input from pipe
function logitp() {
        TS=$(date +%s.%N)
        read LINE
        if [ "X${LOGFILE}" == "X--" ]; then
                cat <<< "${TS}:${PPID}:${$}:${SHELL}:${LINE}"
        else
                cat <<< "${TS}:${PPID}:${$}:${SHELL}:${LINE}" >> ${LOGFILE}
        fi
}

#Log input from arguments
function logita() {
        echo "${@}" | logitp
}

#Figure out from where to where to log
function logger() {
        if input_is term; then
                logita "$@"
        else
                logitp
        fi
}

if [ "$LOGGER_SH" == $( basename $0 ) ]; then
        #Not sourced, do something with this.

        echo "Supposed to be sourced, but might just as well do some tests..."
        # The following tests can be done to cover all cases:
        # logger.sh "This is a test"
        #   => STDOUT: "$X:This is a test"
        #
        # echo "This is a test" | logger.sh
        #   => STDOUT: "$X:This is a test"
        #
        # (export LOGFILE="logfile"; logger.sh "This is a test")
        #   => logfile: "$X:This is a test"
        #
        # (export LOGFILE="logfile"; echo "This is a test" | logger.sh)
        #   => logfile: "$X:This is a test"
        #
        # Where $X above means: ${TS}:${PPID}:${$}:${SHELL}
        if [ "X${LOGFILE}" == "X--" ]; then
                echo
        fi

        logger "$@"

        if [ "X${LOGFILE}" != "X--" ]; then
                echo "Check log-file [${LOGFILE}]"
        fi
fi

fi

## pipe_logic.sh
#! /bin/bash
# Helper functions to determine if in/out is a attached to TERM or PIPE
#
# TERM in this context means attached to a console (screen or keyboard
# depending on context), i.e. potentially interactive.
#
# PIPE means anything else: Pipe, redirect to file, redirect to variable
# e.t.a.
#
# This file is meant to be sourced
#
# Note: Using return-values are needed as testing for console / terminal
# becomes impossible when capturing output, since capturing itself goes via a
# pipe (i.e. resulting answer would always be a pipe regardless of what's
# being tested)
#
# This however also might become cumbersome if/when script sourcing uses
# 'set -e'. The test are designed with this in mind (if on fail should not
# trigger exit), but it might require better error handling to avoid trigger
# false positives.

if [ -z $PIPE_LOGIC_SH ]; then
PIPE_LOGIC_SH=pipe_logic.sh

function whatis_output() {
        if [ -t 1 ]; then
                echo "TERM"
        else
                echo "PIPE"
        fi
}

function whatis_input() {
        if tty -s; then
                echo "TERM"
        else
                echo "PIPE"
        fi
}

function output_is() {
        if [ $# -ne 1 ]; then
                echo "output_is() needs exactly one argument" 2>&1
                exit 1
        fi
        ARG=$(tr '[:lower:]' '[:upper:]' <<< $1)
        case $ARG in
                'TERM')
                        if [ -t 1 ]; then
                                return 0
                        fi
                        ;;
                'PIPE')
                        if ! [ -t 1 ]; then
                                return 0
                        fi
                        ;;
                *)
                        echo "output_is(): Unknown argument [$1]" 2>&1
                        exit 1
                        ;;
        esac
        return 1
}

function input_is() {
        if [ $# -ne 1 ]; then
                echo "input_is() needs exactly one argument" 2>&1
                exit 1
        fi
        ARG=$(tr '[:lower:]' '[:upper:]' <<< $1)
        case $ARG in
                'TERM')
                        tty -s && return 0
                        ;;
                'PIPE')
                        tty -s || return 0
                        ;;
                *)
                        echo "input_is(): Unknown argument [$1]" 2>&1
                        exit 1
                        ;;
        esac
        return 1
}


if [ "$PIPE_LOGIC_SH" == $( basename $0 ) ]; then
        #Not sourced, do something with this.

        echo "Supposed to be sourced, but might just as well do some tests..."
        # The following tests can be done to cover all cases:
        # echo | pipe_logic.sh | cat --
        #   => PIPE / PIPE
        #
        # pipe_logic.sh | cat --
        #   => TERM / PIPE
        #
        # echo | pipe_logic.sh
        #   => PIPE / TERM
        #
        # pipe_logic.sh
        #   => TERM / TERM
        #
        echo

        whatis_output "$@"
        if output_is term; then
                echo "output is terminal"
        fi
        if output_is pipe; then
                echo "output is pipe"
        fi
        echo

        whatis_input "$@"
        if input_is term; then
                echo "input is terminal"
        fi
        if input_is pipe; then
                echo "input is pipe"
        fi
fi

fi
	#! /bin/bash
	# This script updates a dynamic-DNS record for a specific NIC of your host.
	# Script is made for freedns.afraid.org but should in principle work for
	# other providers as well that allow DNS updates by simply loading a
	# specific URL.
	#
	# Usage: dyndns_update.sh IF SHA1
	#
	# As this script is meant to be run from cron, it will be fairly silent,
	# except when something goes wrong in an unexpected way or when a change of
	# IP address actually occurred. (note, some of the fails are normal and not
	# unexpected). To see the output of the log, export the environment variable
	# LOGFILE to "--" (any other content of that variable will write to this
	# file-name).
	#
	# Example: (export LOGFILE="--"; dyndns_update.sh eth1 $MYHOST)

	IFNAME=${1}
	SHA1=${2}
	SHOST=${3-"freedns.afraid.org"}
	SHELL=$(basename $0)

	#Set export of this to "--" if you want output visible
	LOGFILE=${LOGFILE-"/tmp/update_dyndns.log"}
	source logger.sh
	source pipe_logic.sh

	if [ "X$IFNAME" == "X" ]; then
	logger "First argument (IFNAME) must be present. Exiting..."
	exit 1
	fi

	if [ "X$SHA1" == "X" ]; then
	logger "Second argument (SHA1) must be present. Exiting..."
	exit 1
	fi

	NIC_IPNR=$(ifconfig \| \
	grep $IFNAME -A3 \| \
	grep "inet addr" \| \
	cut -f2 -d":" \| \
	cut -f1 -d " ")
	LNET=$(echo $NIC_IPNR \| cut -f1-3 -d".").0
	GW=$(echo $NIC_IPNR \| cut -f1-3 -d".").1
	URL="http://${SHOST}/dynamic/update.php?${SHA1}"

	if [ "X$NIC_IPNR" == "X" ]; then
	logger "IF [$IFNAME] not up or doesn't exist. Exiting..."
	exit 1
	fi

	logger "$(basename $0): Updating dynamic DNS to interface: [$IFNAME]"
	logger " NIC: [$NIC_IPNR]"
	logger " NET: [$LNET]"
	logger " GW: [$GW]"
	logger " URL: [$URL]"
	logger

	# Try removing temporary route first, in case last invocation didn't complete.
	route -v del -host $SHOST >/dev/null 2>&1

	#set -e #Trigger e-mail if something goes wrong from here on & if run in cron
	logger "Setting temporary route for [$SHOST]"
	route -v -A inet add -host $SHOST gw $GW \| logger
	#route -v -A inet add -host $SHOST gw $GW
	netstat -anr \| logger
	#netstat -anr
	logger "Updating dyn-DNS [$URL]"
	RESPONSE=$(wget -O - $URL 2>/dev/null)
	logger "Removing temporary route [$SHOST]"
	route -v del -host $SHOST \| logger
	logger
	logger "Response from service provider [$SHOST] for [$IFNAME]:"
	logger "$RESPONSE"
	set +e #Stop trigger error mails (grep returns fail is not found)
	if [ \
	"X$(echo $RESPONSE \| grep 'has not changed')" == "X" -a \
	"X${LOGFILE}" != "X--" \
	]; then
	# Something else is responded. Make it visable in syslog (if used from
	# cron), might be an error (or at least interesting).
	echo "Response from service provider [$SHOST] for [$IFNAME]:"
	echo "$RESPONSE"
	fi
	#! /bin/bash
	# Helper functions to make nice log-output to the right destination
	#
	# Format is a ":" separated list with each column meaning the following:
	# 1) TS: Time since epoc in nano-seconds. Numerical format makes it ideal
	# or sorting. Recover to human readable date by executing:
	# date -d "${TS}"
	# 2) PPID: Parent ID. Cront, init or your shell.
	# 3) PID: PID of the executing shell
	#
	# This file is meant to be sourced
	if [ -z $LOGGER_SH ]; then
	LOGGER_SH=logger.sh
	source pipe_logic.sh

	LOGFILE=${LOGFILE-"--"}

	#Log input from pipe
	function logitp() {
	TS=$(date +%s.%N)
	read LINE
	if [ "X${LOGFILE}" == "X--" ]; then
	cat <<< "${TS}:${PPID}:${$}:${SHELL}:${LINE}"
	else
	cat <<< "${TS}:${PPID}:${$}:${SHELL}:${LINE}" >> ${LOGFILE}
	fi
	}

	#Log input from arguments
	function logita() {
	echo "${@}" \| logitp
	}

	#Figure out from where to where to log
	function logger() {
	if input_is term; then
	logita "$@"
	else
	logitp
	fi
	}

	if [ "$LOGGER_SH" == $( basename $0 ) ]; then
	#Not sourced, do something with this.

	echo "Supposed to be sourced, but might just as well do some tests..."
	# The following tests can be done to cover all cases:
	# logger.sh "This is a test"
	# => STDOUT: "$X:This is a test"
	#
	# echo "This is a test" \| logger.sh
	# => STDOUT: "$X:This is a test"
	#
	# (export LOGFILE="logfile"; logger.sh "This is a test")
	# => logfile: "$X:This is a test"
	#
	# (export LOGFILE="logfile"; echo "This is a test" \| logger.sh)
	# => logfile: "$X:This is a test"
	#
	# Where $X above means: ${TS}:${PPID}:${$}:${SHELL}
	if [ "X${LOGFILE}" == "X--" ]; then
	echo
	fi

	logger "$@"

	if [ "X${LOGFILE}" != "X--" ]; then
	echo "Check log-file [${LOGFILE}]"
	fi
	fi

	fi
	#! /bin/bash
	# Helper functions to determine if in/out is a attached to TERM or PIPE
	#
	# TERM in this context means attached to a console (screen or keyboard
	# depending on context), i.e. potentially interactive.
	#
	# PIPE means anything else: Pipe, redirect to file, redirect to variable
	# e.t.a.
	#
	# This file is meant to be sourced
	#
	# Note: Using return-values are needed as testing for console / terminal
	# becomes impossible when capturing output, since capturing itself goes via a
	# pipe (i.e. resulting answer would always be a pipe regardless of what's
	# being tested)
	#
	# This however also might become cumbersome if/when script sourcing uses
	# 'set -e'. The test are designed with this in mind (if on fail should not
	# trigger exit), but it might require better error handling to avoid trigger
	# false positives.

	if [ -z $PIPE_LOGIC_SH ]; then
	PIPE_LOGIC_SH=pipe_logic.sh

	function whatis_output() {
	if [ -t 1 ]; then
	echo "TERM"
	else
	echo "PIPE"
	fi
	}

	function whatis_input() {
	if tty -s; then
	echo "TERM"
	else
	echo "PIPE"
	fi
	}

	function output_is() {
	if [ $# -ne 1 ]; then
	echo "output_is() needs exactly one argument" 2>&1
	exit 1
	fi
	ARG=$(tr '[:lower:]' '[:upper:]' <<< $1)
	case $ARG in
	'TERM')
	if [ -t 1 ]; then
	return 0
	fi
	;;
	'PIPE')
	if ! [ -t 1 ]; then
	return 0
	fi
	;;
	*)
	echo "output_is(): Unknown argument [$1]" 2>&1
	exit 1
	;;
	esac
	return 1
	}

	function input_is() {
	if [ $# -ne 1 ]; then
	echo "input_is() needs exactly one argument" 2>&1
	exit 1
	fi
	ARG=$(tr '[:lower:]' '[:upper:]' <<< $1)
	case $ARG in
	'TERM')
	tty -s && return 0
	;;
	'PIPE')
	tty -s \|\| return 0
	;;
	*)
	echo "input_is(): Unknown argument [$1]" 2>&1
	exit 1
	;;
	esac
	return 1
	}


	if [ "$PIPE_LOGIC_SH" == $( basename $0 ) ]; then
	#Not sourced, do something with this.

	echo "Supposed to be sourced, but might just as well do some tests..."
	# The following tests can be done to cover all cases:
	# echo \| pipe_logic.sh \| cat --
	# => PIPE / PIPE
	#
	# pipe_logic.sh \| cat --
	# => TERM / PIPE
	#
	# echo \| pipe_logic.sh
	# => PIPE / TERM
	#
	# pipe_logic.sh
	# => TERM / TERM
	#
	echo

	whatis_output "$@"
	if output_is term; then
	echo "output is terminal"
	fi
	if output_is pipe; then
	echo "output is pipe"
	fi
	echo

	whatis_input "$@"
	if input_is term; then
	echo "input is terminal"
	fi
	if input_is pipe; then
	echo "input is pipe"
	fi
	fi

	fi