#!/bin/sh
# Shebang line included so editors and shellcheck/shfmt know this contains
# shell code

# Create configuration for upsd and UPS drivers for NUT

# In recent (relevant) versions of shellcheck busybox is a valid shell type
# shellcheck shell=busybox

# Pre-requisite sourcing for functions this script uses
# * /lib/functions.sh has been sourced
# * /lib/functions/nut/nut-service.sh has been sourced

# * /lib/functions/nut/nut-common.sh must be source and find_statepath executed
#   before build_config is called

# Ensure find_statepath from nut-service.sh is executed
# before srv_config in this file.

# Ephemeral files, recreated on each OpenWrt boot
USERS_C=/var/etc/nut/upsd.users # NUT user and password file
UPSD_C=/var/etc/nut/upsd.conf   # NUT upsd (UPS daemon) configuration
UPS_C=/var/etc/nut/ups.conf     # NUT UPS configuration (ini-style section per UPS)
NUT_CONF=/var/etc/nut/nut.conf  # NUT mode config

# config_load is done by the sourcing script, before executing any functions in
# this file

# Writes configuration values to the UPS run-time configuration file
get_write_ups_config() {
	local ups="$1"
	local var="$2"
	local def="$3"
	local flag="$4"
	local config_file="$5"
	local val

	if [ -z "$flag" ] || [ "$flag" = "0" ]; then
		config_get val "$ups" "$var" "$def"
		[ -n "$val" ] && printf "%s = %s\n" "$var" "$val" >>"$config_file"
	else
		config_get_bool val "$ups" "$var" "$def"
		# In NUT config a flag is either present or not present
		# present is true, not present is false. Map UCI bool to NUT flags.
		if [ "$val" = "1" ]; then
			printf "%s\n" "$var" >>"$config_file"
		fi
	fi
}

# Add upsd listen address and port to the run-time configuration
listen_address() {
	local srv="$1"
	local config_file="$2"
	local address port

	config_get address "$srv" address "::1"
	config_get port "$srv" port
	if [ -n "$port" ]; then
		printf "LISTEN %s %s\n" "$address" "$port" >>"$config_file"
	else
		printf "LISTEN %s\n" "$address" >>"$config_file"
	fi
}

# Adds upsd (NUT server) run-time configuration
srv_config() {
	local srv="$1"
	local config_file="$2"
	local maxage maxconn certfile

	config_get maxage "$srv" maxage
	[ -n "$maxage" ] && printf "MAXAGE %s\n" "$maxage" >>"$config_file"

	[ -n "$STATEPATH" ] && printf "STATEPATH %s\n" "$STATEPATH" >>"$config_file"

	config_get maxconn "$srv" maxconn
	[ -n "$maxconn" ] && printf "MAXCONN %s\n" "$maxconn" >>"$config_file"

	#NOTE: certs only apply to SSL-enabled version
	config_get certfile "$srv" certfile
	[ -n "$certfile" ] && printf "CERTFILE %s\n" "$certfile" >>"$config_file"
}

nut_user_instcmd() {
	local val="$1"
	local config_file="$2"
	printf "  instcmds = %s\n" "$val" >>"$config_file"
}

# Adds run-time configuration for NUT users to the upsd.users file
nut_user_add() {
	local user="$1"
	local config_file="$2"
	local a
	local val

	config_get val "$user" username "$user"
	printf "[%s]\n" "$val" >>"$config_file"

	config_get val "$user" password
	[ -n "$val" ] && printf "  password = %s\n" "$val" >>"$config_file"

	config_get val "$user" actions
	set -f
	for a in $val; do
		printf "  actions = %s\n" "$a" >>"$config_file"
	done
	set +f

	# The name instcmd is use for both the UCI option and the callback function
	config_list_foreach "$user" instcmd nut_user_instcmd "$config_file"

	config_get val "$user" upsmon
	if [ -n "$val" ]; then
		printf "  upsmon %s\n" "$val" >>"$config_file"
	fi
}

# Builds upsd (NUT server) run-time configuration
build_server_config() {
	local conf_group="$1"
	local nut_conf_err="false"

	umask 022
	mkdir -p "$(dirname "$UPSD_C")" || {
		log_error "Failed to create directory for upsd configuration file '$UPSD_C'" nut-server-config.sh nut-server-config
		return 1
	}

	rm -f "$USERS_C.new"
	rm -f "$UPSD_C.new"

	umask 117
	echo "# Config file automatically generated from UCI config" >"$USERS_C.new"
	echo "# Config file automatically generated from UCI config" >"$UPSD_C.new"
	restore_umask

	# For nut_user and listen_address, the section type and callback function
	# are named the same
	config_foreach nut_user_add user "$USERS_C.new"
	config_foreach listen_address listen_address "$UPSD_C.new"
	if have_section_of_type "upsd"; then
		config_foreach srv_config upsd "$UPSD_C.new"
	else
		# If config 'nut_server' does not have a 'upsd' section, use a default
		# configuration
		[ -n "$STATEPATH" ] && printf "STATEPATH %s\n" "$STATEPATH" >>"$UPSD_C.new"
	fi

	# Failure to write nut.conf is not hard-fatal although it means the NUT will
	# not start the service.
	# Also, we only write nut.conf if there is not one already
	if [ ! -s "$NUT_CONF" ] || grep -q '^MODE=none' "$NUT_CONF"; then
		umask 133
		if ! printf "MODE=netserver\n" >"$NUT_CONF"; then
			log_error "nut-server creation of nut.conf failed" nut-server-config.sh nut-server-config
			return 1
		fi
	else
		# Otherwise if nut-server is already configured, make sure both
		# nut-server (this service) and nut-monitor are started
		if grep -q '^MODE=netclient' "$NUT_CONF"; then
			# In modern OpenWrt 'sed -i' modifies the specified files, without backup
			sed -i -e 's/^MODE=netclient/MODE=both/' "$NUT_CONF" || {
				log_error "Failed to update nut.conf to support both upsmon and upsd" nut-server-config.sh nut-server-config
				nut_conf_err="true"
			}
		fi
	fi

	if [ "$nut_conf_err" = "false" ] && [ -n "$conf_group" ]; then
		chgrp "$conf_group" "$USERS_C.new" || {
			log_error "failed to set group on '$USERS_C.new'" nut-server-config.sh nut-server-config
			nut_conf_err="true"
		}
		chgrp "$conf_group" "$UPSD_C.new" || {
			log_error "failed to set group on '$UPSD_C.new'" nut-server-config.sh nut-server-config
			nut_conf_err="true"
		}
	fi

	# shellcheck disable=SC2034
	[ "$nut_conf_err" = "false" ] || return 1
}

# shellcheck disable=SC2317,SC2329
nut_ups_defoverride() {
	local overvar="$1"
	local defover="$2"
	local config_file="$3"
	local ups="$4"
	local overtype
	local overval

	# tr is used as global replace in variable parameter expansion is not
	# available in ash.
	overtype="$(printf "%s" "$overvar" | tr '_' '.')"

	config_get overval "$ups" "${defover}_${overvar}"
	[ -n "$overval" ] && printf "%s.%s = %s\n" "${defover}" "${overtype}" "$overval" >>"$config_file"
}

# From documentation and fixing of nut_ups_other (previously other or do_other)
# function (below) in https://github.com/rpavlik in
# https://github.com/openwrt/packages/pull/28308
#
# For each value "x" in the per-driver ($ups) list "other", get the value of
#   per-driver config variable "other_x", and if it is not empty,
#   write "x = {value of other_x}" to the config file.
# For each value "x" in the per-driver ($ups) list "otherflag", get the value of
#   per-driver config variable "otherflag_x", and if it is true, write
#  "x" to the config file.

# shellcheck disable=SC2317,SC2329
nut_ups_other() {
	local othervar="$1"
	local othervarflag="$2"
	local config_file="$3"
	local ups="$4"
	local otherval

	if [ "$othervarflag" = "otherflag" ]; then
		config_get_bool otherval "${ups}" "${othervarflag}_${othervar}"
		[ "$otherval" = "1" ] && printf "%s\n" "${othervar}" >>"$config_file"
	else
		config_get otherval "${ups}" "${othervarflag}_${othervar}"
		[ -n "$otherval" ] && printf "%s = %s\n" "${othervar}" "$otherval" >>"$config_file"
	fi
}

# Builds UPS-specific run-time configuration
build_ups_config() {
	local ups="$1"
	local config_file="$2"

	printf "[%s]\n" "$ups" >>"$config_file"

	get_write_ups_config "$ups" bus "" "" "$config_file"
	get_write_ups_config "$ups" cable "" "" "$config_file"
	get_write_ups_config "$ups" community "" "" "$config_file"
	get_write_ups_config "$ups" desc "" "" "$config_file"
	get_write_ups_config "$ups" driver "usbhid-ups" "" "$config_file"
	get_write_ups_config "$ups" ignorelb 0 1 "$config_file"
	get_write_ups_config "$ups" interruptonly 0 1 "$config_file"
	get_write_ups_config "$ups" interruptsize "" "" "$config_file"
	get_write_ups_config "$ups" maxreport "" "" "$config_file"
	get_write_ups_config "$ups" maxstartdelay "" "" "$config_file"
	get_write_ups_config "$ups" mfr "" "" "$config_file"
	get_write_ups_config "$ups" model "" "" "$config_file"
	get_write_ups_config "$ups" nolock 0 1 "$config_file"
	get_write_ups_config "$ups" notransferoids 0 1 "$config_file"
	get_write_ups_config "$ups" offdelay "" "" "$config_file"
	get_write_ups_config "$ups" ondelay "" "" "$config_file"
	get_write_ups_config "$ups" pollfreq "" "" "$config_file"
	get_write_ups_config "$ups" port "auto" "" "$config_file"
	get_write_ups_config "$ups" product "" "" "$config_file"
	get_write_ups_config "$ups" productid "" "" "$config_file"
	get_write_ups_config "$ups" retrydelay "" "" "$config_file"
	get_write_ups_config "$ups" sdorder "" "" "$config_file"
	get_write_ups_config "$ups" sdtime "" "" "$config_file"
	get_write_ups_config "$ups" serial "" "" "$config_file"
	get_write_ups_config "$ups" shutdown_delay "" "" "$config_file"
	get_write_ups_config "$ups" snmp_version "" "" "$config_file"
	get_write_ups_config "$ups" snmp_retries "" "" "$config_file"
	get_write_ups_config "$ups" snmp_timeout "" "" "$config_file"
	get_write_ups_config "$ups" synchronous "" "" "$config_file"
	get_write_ups_config "$ups" usd "" "" "$config_file"
	get_write_ups_config "$ups" vendor "" "" "$config_file"
	get_write_ups_config "$ups" vendorid "" "" "$config_file"

	# Params specific to NetXML driver
	get_write_ups_config "$ups" login "" "" "$config_file"
	get_write_ups_config "$ups" password "" "" "$config_file"
	get_write_ups_config "$ups" subscribe 0 1 "$config_file"

	config_list_foreach "$ups" override nut_ups_defoverride override "$config_file" "$ups"
	config_list_foreach "$ups" default nut_ups_defoverride default "$config_file" "$ups"

	# For each entry in the "$ups" list "other", get the
	# variable "other_${entry}", and if not empty, write
	# "${entry} = ${value of other_${entry}}" to the config file.
	config_list_foreach "$ups" other nut_ups_other other "$config_file" "$ups"

	# For each entry in the "$ups" list "otherflag", get the
	# variable "otherflag_${entry}", and if true, write "${entry}" to
	# the config file.
	config_list_foreach "$ups" otherflag nut_ups_other otherflag "$config_file" "$ups"

	echo "" >>"$config_file"
	# shellcheck disable=SC2034
	haveupscfg=true
}

# Add global drivers settings to run-time config
build_global_driver_config() {
	local cfg="$1"
	local config_file="$2"

	# Global driver config
	get_write_ups_config "$cfg" chroot "" "" "$config_file"
	get_write_ups_config "$cfg" driverpath "" "" "$config_file"
	get_write_ups_config "$cfg" maxstartdelay "" "" "$config_file"
	get_write_ups_config "$cfg" maxretry "" "" "$config_file"
	get_write_ups_config "$cfg" retrydelay "" "" "$config_file"
	get_write_ups_config "$cfg" pollinterval "" "" "$config_file"
	get_write_ups_config "$cfg" synchronous "" "" "$config_file"
	echo "" >>"$config_file"
}

# Orchestrate the run-time configuration building process
build_config() {
	local conf_group
	# 'pseudo-global' to allow config_foreach build_ups_config to signal that
	# at least one UPS section was configured. We do not want return 1 in
	# the config_foreach as that would abort processing for other UPS sections.
	local haveupscfg="false"

	if [ -z "$RUNAS" ]; then
		log_error "RUNAS is empty; cannot determine group for configuration files" nut-server-config.sh nut-server-config
		return 1
	fi

	if ! conf_group="$(id -gn "$RUNAS")"; then
		log_error "Failed to determine group for user '$RUNAS'" nut-server-config.sh nut-server-config
		return 1
	fi
	[ -n "$conf_group" ] || return 1

	# shellcheck disable=SC2153
	[ -d "$STATEPATH" ] || {
		umask 007
		mkdir -p "$STATEPATH" || {
			# We hard fail here, as we cannot rely on service state if
			# STATEPATH does not exist
			log_error "Failed to create ${STATEPATH}." nut-server nut-server
			# return so we can do cleanup
			return 1
		}
		if [ -n "$conf_group" ]; then
			chown "root:${conf_group}" "$STATEPATH" || {
				log_error "Failed to change owner:group on STATEPATH ('$STATEPATH')" nut-server-config.sh nut-server-config
				return 1
			}
		fi
	}

	# At this point we know STATEPATH exists and we have either created it with
	# the required owner, group, and permissions, or it was created elsewhere.
	# We do not second-guess other sources of creating this STATEPATH and
	# presume that as long as we have read and traversal access, that the
	# permissions are intentional. As 'stat' is not available by default in
	# OpenWrt we just check if we can read and traverse the directory.
	if [ ! -r "$STATEPATH" ] || [ ! -x "$STATEPATH" ]; then
		log_error "We do not have access to STATEPATH '$STATEPATH'." nut-server-config.sh nut-server-config
		return 1
	fi

	# This directory is shared with the nut-monitor which runs as a different
	# user and group, so must be all readable. We set the ownership and
	# permissions on individual files more restrictively, as needed
	# shellcheck disable=SC2174
	umask 022
	mkdir -p "$(dirname "$UPS_C")"
	rm -f "$UPS_C"
	umask 137
	echo "# Config file automatically generated from UCI config" >"$UPS_C.new"
	chgrp "$conf_group" "$UPS_C.new" || {
		log_error "Failed to change group on UPS_C.new (new UPS config)" nut-server-config.sh nut-server-config
		return 1
	}

	config_foreach build_global_driver_config driver_global "$UPS_C.new"
	config_foreach build_ups_config driver "$UPS_C.new"

	if ! build_server_config "$conf_group"; then
		log_msg "Failed to configure upsd. Not starting." nut-server-config.sh nut-server-config warn
		return 1
	elif [ "$haveupscfg" = "false" ]; then
		log_msg "No configured UPS. Not starting upsd." nut-server-config.sh nut-server-config warn
		return 2
	fi
	return 0
}