#!/bin/bash

# Collection of small bash functions utilized in various scripts.
################################################################################
export PATH=$PATH:/opt/openslx/bin:/opt/openslx/sbin

dmstate="/run/openslx/dmsetup.state"
readonly dmstate

df_dev_only() {
	df -P "$1" 2>&1 | awk '$1 ~ /^\/dev\// {print $0}'
}

get_backing_dev() {
	local _dev="$(df_dev_only "$1" | awk '{print $1}' )"
	[ -b "$_dev" ] || return 1
	echo "$_dev"
}
get_backing_dev_mp() {
	local _mp="$(df_dev_only "$1" | awk '{print $6}')"
	[ -d "$_mp" ] || return 1
	echo "$_mp"
}
# Helper to check whether given directory resides in RAM, either
# by being mounted as tmpfs or not mounted at all in which case
# we assume the same. Returns 0 if so, 1 if otherwise backed,
# 2 when errors occur.
is_volatile() {
	[ -z "$1" ] && return 2
	local _dev="$(get_backing_dev "$1")"
	[ -z "$_dev" ] && return 0
	# NOTE: ash does not search/replace when the expression is surrounded by quotes
	[ "x$_dev" = "x"${_dev//\/dev\/mapper/} ] && return 1
	local _mp="$(get_backing_dev_mp "$1")"
	[ -z "$_mp" ] && return 2
	# it is a device mapper device, check if it was setup in dracut's initramfs.
	if [ -s "$dmstate" ]; then
		grep -qE "^${_dev}\s+${_mp}\s+type=0" "$dmstate"
		return $?
	fi
	return 2
}

get_dm_backing_size() {
	[ -z "$1" ] && return 1
	local _dev="$(get_backing_dev $1)"
	# NOTE: ash does not search/replace when the expression is surrounded by quotes
	[ "x$_dev" = "x"${_dev//\/dev\/mapper/} ] && return 1
	local _dm_line="$(grep -m1 -E "^${_dev}\s+/\s+type=[^0]" "$dmstate")"
	[ -z "$_dm_line" ] && return 1
	local _dm_dev_size="$(echo "$_dm_line" | grep -Po '(?<=physical_size=|virtual_size=)\w*' )"
	echo ${_dm_dev_size:--1}
}

regex_match() {
	echo "$1" | grep -qE "$2"
}

get_partitions_by_id () {
	local ID dev exp target
	exp=
	# target for the scan, defaults to /dev to check everything
	target=/dev
	if [ -b "$1" ]; then
		target="$1"'*'
		shift
	fi
	# support commas and pipes to separate identifiers
	local args=$@
	set -- ${args//[,|]/ }
	while [ $# -gt 0 ]; do
		ID=$1
		shift
		[ -z "$ID" ] && continue
		# if single digit, e.g. 7, look for 0x7 and 0x07
		#[[ $ID =~ ^[0-9]$ ]] && ID="0?$ID"
		if regex_match "$ID" "^[0-9]$"  ; then
			ID="0?$ID"
		fi

		if regex_match "$ID" "^[0-9]{2}$"; then
			# if double digit look for MBR types and OpenSLX-ID$ID GPT labels
			exp="$exp|ID_PART_ENTRY_(NAME=OpenSLX-ID|TYPE=0x)$ID"
		elif regex_match "$ID" "^(0x[0-9]{2}|[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12})$"; then
			# if full MBR type (e.g. 0x44) or UUID look for TYPE
			exp="$exp|ID_PART_ENTRY_TYPE=$ID"
		else
			# something else, look for names of partitions / filesystems
			exp="$exp|ID_(PART_ENTRY_NAME|FS_LABEL)=$ID"
		fi
	done
	exp=${exp:1}
	#echo "Partition find is '$exp'" >&2
	for dev in $(find $target -type b); do
		udevadm info --name="$dev" | grep -iqE "($exp)\$" \
			&& echo "$(blockdev --getsize64 "$dev") $dev"
	done | sort -n -k1 -r | cut -d' ' -f2
}