bgrun

#!/sbin/openrc-run

#
# Copyright (c) 2021: Jacob.Lundqvist@gmail.com 2021-05-20
# License: MIT
#
# This service reads the GPS and discards the output to /dev/null. 
# So this is not tracking you in any way. The sole purpose of this
# is that this is the only way to ensure an iOS program continues to run
# in the background.
# This process has no noticeable impact on battery life.
#

name="run in background"
description="Reads GPS to ensure iSH continues to run when in background"

command="cat"
command_args="/dev/location > /dev/null"
command_background="YES"

pidfile="/run/$RC_SVCNAME.pid"


#
# The above is all that is needed to have cat /dev/location > /dev/null
# run as a simple daemon with pid beaning monitored.
#
# The below parts are just adding some additional sanity, not needed
# in order for the daemon to woek by itself.
#
# Pointless to have more than one thing doing this. 
# The below aborts with error if:  cat /dev/location
# is already running.
# And displays warning if other processes are detected
# after stoping.
#

check_for_other_polling() {
    other_pids=$(ps |grep "cat /dev/location" | grep -v grep | awk '{ print $1 }' |  tr '\n' ' ')
}


start_pre() {
    check_for_other_polling
    if [ "$other_pids" != "" ]; then
	eerror "ERROR: Other processes polling GPS [ $other_pids]"
   fi
}


stop_post() {
    check_for_other_polling
    if [ "$other_pids" != "" ]; then
	ewarn "WARNING: Other processes polling GPS [ $other_pids]"
   fi
}