simbamon

#!/bin/bash
#
# simbamon -- a simple battery monitor
#
# Author: Hamish Cunningham <hamish@gate.ac.uk>
# This code is copyright Hamish Cunningham and the University of Sheffield
# and is licenced under GPL 3 or any later version.
#
### BEGIN INIT INFO
# Provides:          simbamon
# Short-Description: simbamon: a simple battery monitor daemon
# Description:       This script checks battery level and
#                    reports it
### END INIT INFO

# standard locals
P="$0"
USAGE="`basename ${P}` [-h(elp)] [-d(ebug)] [-v(ersion)]"
OPTIONSTRING=hdv

# define LSB log_* functions.
. /lib/lsb/init-functions

# message & exit if exit num present
usage() { log_action_msg Usage: $USAGE; [ ! -z "$1" ] && exit $1; }

# defaults
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/bin
DESC="simbamon: a simple battery monitor daemon"
NAME=simbamon
DNAME=simbamond
DAEMON=/usr/sbin/$NAME
PIDFILE=/var/run/$DNAME.pid
SHUTDOWN="rm $PIDFILE && halt && exit 0"
INST_DIR=`dirname ${P}`
CLI=${INST_DIR}/mopicli
STATUS_LOG_NEEDED=true

# options defaults
DEBUG=off

# read configuration variable file if it is present
if [ -r /etc/default/$DNAME ] 
then
  . /etc/default/$DNAME
elif [ -r ./$DNAME.default ]
then
  . ./$DNAME.default
else
  logger "$0: no config data found - fatal error"
  exit 1
fi

# process options
[ ! -z "$*" ] && log_daemon_msg ${NAME} options: $*
while getopts $OPTIONSTRING OPTION
do
  case $OPTION in
    h)	usage 1 ;;
    d)	DEBUG=on ;;
    v)  log_action_msg Version $VERSION; usage 0 ;;
    *)	usage 2 ;;
  esac
done 
shift $(( $OPTIND - 1 ))

# pretty date/time function
pdate() { date +%b-%d-%Y-%T; }

# tell the world
logger "$0: version $VERSION running at `pdate`"
logger "${NAME}: monitor frequency is ${MONITOR_FREQUENCY} seconds"
[ "${DEBUG}" = on ] && logger "${NAME}: DEBUG is ${DEBUG}"

# check mopicli installed and working
${CLI} -s >/dev/null || {
  COUT=`${CLI} -s 2>&1`
  echo "${P}: ${CLI} not working; MoPi not attached or powered? (${COUT})" >&2
  logger "${P}: ${CLI} not working; MoPi not attached or powered? (${COUT})"
}

# how many loops to wait between warnings when battery is low
WAIT_LOOPS=$(( $WARNING_INTERVAL / $MONITOR_FREQUENCY ))
PREV_WARNING=0

# i and j index loop iterations for controlling logging and messages
i=0; j=0

# infinite loop (backgrounded)
while :
do
  i=$(( ${i} + 1 )); j=$(( ${j} + 1 ))

  # on first boot ...
  [ -z "$PREVIOUSLY_RUN" -a ! -f "$PREVIOUSLY_RUN_INDICATOR" ] && {
    date > $PREVIOUSLY_RUN_INDICATOR

    # ...take a short break
    logger "${NAME}: first run after boot, sleeping for ${BOOT_DELAY}..."
    sleep $BOOT_DELAY
    logger "${NAME}: ...boot delay done"
  }

  # on first loop after start...
  [ -z "$PREVIOUSLY_RUN" ] && {
    PREVIOUSLY_RUN=true

    # ...push local config up to the board
    OIFS="$IFS"
    IFS='
'
    for l in `get_local_config`
    do
      IFS="${OIFS}"
      COM="${CLI} `echo \"${l}\" |sed 's/# wc[12]*: //'`"
      if check_local_config "$COM"
      then
        logger "${NAME}: writing local config ${COM}"
        OUT=`$COM` || { logger "${NAME}: error writing config: ${OUT}"; }
      else
        logger "${NAME}: ignoring badly constructed local config ($COM)"
        echo "${NAME}: ignoring badly constructed local config ($COM)" >&2
      fi
      IFS='
'
    done
    IFS="${OIFS}"
  }

  # get MoPi status
  MOPI_STATUS="`${CLI} -nl -s`"
  [ "$STATUS_LOG_NEEDED" = true ] && {
    logger "${NAME}: MOPI_STATUS is ${MOPI_STATUS}"
    STATUS_LOG_NEEDED=false
  }

  # the status word must be an integer
  echo "$MOPI_STATUS" |grep -q '^[0-9][0-9]*$' || {
    logger "${NAME}: invalid MOPI_STATUS (${MOPI_STATUS}): will pause/retry..."
    sleep $WARNING_INTERVAL
    continue
  }

  # log low levels (approx. once every 5 minutes unless debugging)
  [ "$DEBUG" = on -o $(( $i % 150 )) -eq 0 ] && {
    ( s_bat_low "$MOPI_STATUS" || s_bat_critical "$MOPI_STATUS" ) && \
      logger "${NAME}: power is at or below warning level (${MOPI_STATUS})"
  }

  # action states (shutdown or warn)
  if s_forced_shutdown "$MOPI_STATUS"
  then
    wall <<< "${NAME}: power off requested: shutting down now!!!"
    logger "${NAME}: shutting down (POWER_OFF; ${MOPI_STATUS})"
    eval "$SHUTDOWN"
  elif s_bat_critical "$MOPI_STATUS"
  then
    wall <<< "${NAME}: battery empty: shutting down now!!!"
    logger "${NAME}: shutting down (BAT_SHUTDOWN; ${MOPI_STATUS})"
    eval "$SHUTDOWN"
  elif s_bat_low "$MOPI_STATUS"
  then
    if [ $PREV_WARNING -eq 0 -o $(( $i - $PREV_WARNING )) -ge $WAIT_LOOPS ]
    then
      PREV_WARNING=$i
      wall <<< "${NAME}: power is low! connect new battery or shut down"
      logger "${NAME}: BAT_WARNING (${MOPI_STATUS})"
    fi
  fi

  # routine log messages
  [ "$DEBUG" = on -o ${j} -eq ${LOG_INTERVAL} ] && \
    logger "${NAME}: status is ${MOPI_STATUS} (i=${i})" && j=0

  # take a break
  sleep ${MONITOR_FREQUENCY}
done &

# create PIDFILE
echo $! >${PIDFILE}