#!/usr/bin/ksh
#!/usr/bin/bash

# flushwait:
# wait until a detached command like amflush has completed
# requires a POSIX compatible shell like ksh or bash
#
# Default program to wait for: amflush (specified with cmd line arg)
# Default checking granularity: 60 seconds (time between checks - specified with -g <seconds>)
# Default command to execute: none, but remaining arguments will be executed at end

# uncomment for debugging
# set -x
# PS4='[$LINENO] '

ProgName=${0##*/}

usage() {
    echo "Usage: ${ProgName} [-g <seconds between checks>] [prog to wait for [cmd to run]]" >&2
    exit 1
}

# defaults

ProgToWaitFor=amflush
Granularity=60

# check for -g option

case "${1}" in
-g)	Granularity=${2}
	shift
	shift
	;;
-g*)	Granularity=${1#-g}
	shift
	;;
-*|+*)	echo "${ProgName}: ${1}: Invalid option" >&2
	usage
	;;
esac

# check that granularity is numeric

if echo "${Granularity}" | grep '^[0-9][0-9]*$' > /dev/null 2>&1
then
	:
else
	echo "${ProgName}: ${Granularity}: granularity must be an integer" >&2
	exit 1
fi

# check for alternate program to wait for instead of amflush

if [ "${1}" != "" ]
then
	ProgToWaitFor="${1}"
	shift
fi

# Any remaining arguments will be executed at end,
# after ProgToWaitFor completes

# It is assumed that ProgToWaitFor is already running
# Gets its process id number now.  There could be multiple
# instances; all must complete for this program to end

ProgPid=$(ps -e | grep "[ /]${ProgToWaitFor}$" | awk '{print $1}')


if [ "${ProgPid}" = "" ]
then
	echo "${ProgName}: '${ProgToWaitFor}': no instance of this program running" >&2
	exit 1
fi
# echo PID is $ProgPid # debugging info

# kill -0 tests for the existance of a the process
# both kill and sleep are builtin commands in most posix shells
# so no extra processes are generated by this loop

while kill -0 ${ProgPid} 2> /dev/null
do
	sleep ${Granularity}
done

# echo $ProgToWaitFor is complete

"${@}"