#!/bin/bash
# Register for with radio-reset-monitor to
# get a signal when radio-reset occurs.
# Child process exists so the parent
# does not need to worry about resets
# starting before it can get through
# checks, and possibly sleeping forever.
# pgrep was needed to kill the sleep.
# wait is called to wait for the SIGUSR1 signal.
# The child never terminates.
# The hope is that the parent will fall into wait
# before the child registers for the radio-reset.
# checking for do_wait is risky if the kernel ever
# changes.  The child will exit if the reset is not
# in process.
# 

USR1=10
TERM=15
function sleep_reset
{
    # Wait for parent to enter wait.
    trap "exit 0" $TERM
    while [[ $(ps -h -o wchan -p $PPID) != do_wait ]] ; do usleep 100 ; done
    echo Register parent for SIGUSR1
    echo "$$" "$USR1" >/sys/devices/platform/mts-io/radio-reset-monitor
    discovered=$(cat /sys/devices/platform/mts-io/radio-udev-discovery)
    if ((discovered == 1)) ; then
       # reset is not in progress.
       exit 0
    fi
    sleep 4294967295  # Hopefully forever
    exit 0
}

date
trap ":" $USR1
in_reset=$(cat /sys/devices/platform/mts-io/radio-udev-discovery)
if ((in_reset == 0)) ; then
    sleep_reset &
    wait $!
    # pgrep is needed to find the sleep process
    pgrep -P $! | xargs kill
fi
echo "$$" "0" >/sys/devices/platform/mts-io/radio-reset-monitor
echo Radio Reset is done.
date
sleep 30