target-config

#! /bin/bash
# creates a configuration for target system that can be piped to a file

rmt_run(){
	#params:
	#  ssh_host
	#  exec
	#  rmt_var - where to store results
	[ $# -ne 3 ] && exit 1
	local ssh_host
	local exec
	local result_var
	local out
	local rc
	ssh_host=$1
	exec=$2
	result_var=$3
	
	out=$( ssh $ssh_host "$exec" 2> /dev/null )
	rc=$?
	printf -v "${result_var}" '%s' "${out}"
	return $rc
}

find_rmt_bins() {
	# params:
	#	ssh host
	#	list of exec to find
	#	results var
	[ $# -ne 3 ] && exit 1
	local ssh_host
	local execs
	local result_var
	local cmd
	local p
	local paths
	local x
	local IFS
	local e
	local uid
	ssh_host=$1
	declare -a execs=($2)
	result_var=$3
	
	#get remote users id
	rmt_run $ssh_host "id -u 2> /dev/null" "uid"
	
	#build command to run
	for e in ${execs[*]}; do
		cmd="$cmd x=\$(which $e);test \$? -eq 0 && echo \$x || echo 'not found';"
	done

	# run it
	rmt_run $ssh_host "$cmd" "$result_var"
	
	#check for missing paths
	x=0
	IFS=$'\n'
	for p in ${!result_var}; do
		if [[ "${p:0:1}" != "/" ]]; then
			# try to find it
			guess_rmt_bin $ssh_host ${execs[$x]}
			if [ -z ${_guess_rmt_bin} ]; then
				p="    "
			else
				p="${_guess_rmt_bin}"
			fi
		fi
		# root doesn't need sudo
		if [[ ${execs[$x]} == sudo && $uid -eq 0 ]]; then
			p='    '
		fi
		paths="${paths}${p}"$'\n'
		x=$(( x + 1 ))
	done
	printf -v "${result_var}" '%s' "${paths}"
	
}

guess_rmt_bin() {
	# params
	#	ssh host
	#	exec
	[ $# -ne 2 ] && exit 1
	local ssh_host
	local ex
	local path_list
	local k
	local cmd
	local IFS
	ssh_host=$1
	ex=$2
	path_list="/sbin /bin /usr/sbin /usr/bin /usr/gnu/bin /opt/local/bin /opt/local/sbin"
	
	#build command to run
	IFS=' '
	for k in $path_list; do
		cmd="$cmd if [ -x $k/$ex ]; then echo $k/$ex; exit 0; fi;"
	done
	
	# run it
	rmt_run $ssh_host "$cmd" "_${FUNCNAME}"
}

usage() {
	echo "Usage: $(basename $0 .sh) --host hostname"
	exit 0
}

declare -a RMT_VARS=('RMT_SUDO=%s' 'RMT_ZFS="$RMT_SUDO %s"' 'RMT_GZIP=%s' 'RMT_XZCAT=%s' 'RMT_NC=%s' 'RMT_SOCAT=%s' 'RMT_MBUFFER=%s' 'RMT_CAT=%s' 'RMT_OPENSSL=%s' )
EXECS="sudo zfs gzip xzcat nc socat mbuffer cat openssl"
RMT_BINS=
CONFIG_PATH=/etc/zfs-repl
 
while [ $# -gt 0 ];do
	case $1 in 
		-H|--host)
			shift
			HOST=$1
			;;
		*)
			usage
			;;
	esac
	shift
done

[ -z $HOST ] && usage

HOST_CONF=$CONFIG_PATH/$HOST.conf

CONFIG="# remote target for zfs-repl"$'\n'

find_rmt_bins $HOST "$EXECS" "RMT_BINS"
IFS=$'\n'
i=0
for v in $RMT_BINS; do
	printf -v t "${RMT_VARS[$i]}" "$v"
	CONFIG="${CONFIG}${t}"$'\n'
	i=$(( i + 1 ))
done

echo "$CONFIG"