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

# Service helper functions for NUT server initscript

# 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/network.sh has been sourced
# * /lib/functions/nut/nut-common.sh has been sourced
# * /usr/share/libubox/jshn.sh has been sourced
# * /lib/functions/procd.sh has been sourced (automatic for initscripts)

# /var/run/killpower is a system-level sentinel created by another program
# which indicates that the system should be powering off
# /var/run is typically a tmpfs on OpenWrt and is not persisted across reboots
NUT_KILLPOWER="/var/run/killpower"

# Disable NUT hotplug path
NUT_DISABLE_HOTPLUG_PATH="/var/run/nut/disable-hotplug"

# Fallback STATEPATH setting
NUT_BASE_STATEPATH="/var/run/nut"

# STATEPATH and RUNAS values are not valid until after find_statepath
# and/or find_runas
# shellcheck disable=SC2034
STATEPATH=""
# shellcheck disable=SC2034
RUNAS=""

# Default delay between interface change and interface trigger reload action
DEFAULT_PROCD_INTERFACE_RELOAD_DELAY=3000

allow_hotplug_restart() {
	# Allow hotplug to restart driver only if no NUT forced shutdown
	# (as indicated by /var/run/killpower) is in progress
	# and hotplug is not disabled

	# NUT_KILLPOWER is a sentinel created by another program
	# which indicates that the system should be powering off
	[ ! -f "$NUT_KILLPOWER" ] || return 1

	# Disable hotplug path; a sentinel created by config
	# or nutshutdown
	[ ! -f "$NUT_DISABLE_HOTPLUG_PATH" ] || return 1

	return 0
}

# Emit list of running UPS service instances (empty if none)
# returns 0 if there are active instances, 1 if no instances are active
# 'service' (first positional parameter) must not come from user input, and is
# expected to be static values provided by developers
list_running_instances() {
	local service="$1"
	local running_instances service_filter

	check_safe_uci_name "$service" || return 1

	service_filter="@['""$service""'][@.*.running=true]"
	running_instances="$(_procd_ubus_call list | jsonfilter -e "$service_filter")"

	if [ -n "$running_instances" ]; then
		json_init
		json_load "$running_instances" || {
			logger -s -t nut-service "json_load failed in list_running_instances"
			return 1
		}
		json_get_keys instance_names
		# shellcheck disable=SC2154
		echo "$instance_names"
		json_cleanup
		return 0
	fi
	return 1
}

# Send a signal to a UPS service instance
# **Not to be used with user input**, only use static information provided by
# developers as signal_command and secondary_command execute commands in the
# script's context
signal_instance() {
	if [ "$#" -lt 7 ]; then
		log_error "signal_instance called with too few parameters."
		return 1
	fi
	local instance_name="$1"
	local signal_command="$2"
	local signal_action="$3"
	local signal="$4"
	local pidfile="$5"
	local signal_extra_arg="$6"
	local service_name="$7"
	# We use shift here and below to allow use of additional variadic parameters
	shift 7
	local secondary_command="$1"
	shift || true
	local process_name ret

	process_name=$(basename "$signal_command")

	# Prefer sending signal using '$signal_command', which requires that a
	# PID file exists. Otherwise, send signal(s) to the process(es) by their
	# instance name
	if [ -s "$pidfile" ]; then
		# Informational log message, not error
		log_msg "Sending signal action '$signal_action' to '$signal_command' for '$instance_name'" "nut-service.sh" "$service_name" "info"
		set -f
		# **Not to be used with user input**
		# shellcheck disable=SC2086
		if [ -n "$signal_extra_arg" ]; then
			"$signal_command" -c "$signal_action" -a "$signal_extra_arg"
			ret=$?
		else
			"$signal_command" -c "$signal_action"
			ret=$?
		fi
		set +f
		# Modern OpenWrt (since OpenWrt-24.10, which is old stable, two releases
		# prior to the release targetted by this script) has pgrep with the expected
		# functionality--it, however, cannot send signals to processes.
	elif pgrep "$process_name" >/dev/null 2>/dev/null; then
		# If 'process_name' is in the process table, signal it with procd_send_signal
		# Informational log message, not error
		log_msg "Sending signal '$signal' to '$instance_name'" "nut-service.sh" "$service_name" "info"
		procd_send_signal "$service_name" "$instance_name" "$signal"
		ret=$?
	else
		# No matching instance/process, which is an allowed possible state.
		:
	fi

	# **Not to be used with user input**
	# For NUT exit code 0 is success, 1 is error, and other codes have other meanings
	# We only want to issue secondary command if the primary command fails
	if [ "$ret" = "1" ] && [ -n "$secondary_command" ] && procd_running "$service_name" "$instance_name"; then
		# Informational log message, not error
		logger -s -t "$service_name" "Performing '$secondary_command' $* for '$instance_name'"
		set -f
		"$secondary_command" "$@" 2>&1 | logger -s -t "$service_name"
		set +f
	fi
	# No signal sent is a valid possibility. Also, if sending a signal fails
	# we want to keep going, so don't error, but do log the condition.
	return 0
}

# Store path for NUT working data in the global variable STATEPATH
# shellcheck disable=SC2329
find_statepath() {
	local section="$1"
	local package="$2"
	local ret statepath

	# Subshell so as not to interfere with main config_load
	(
		config_load "$package" || {
			log_config_load_error "$package" "nut-service.sh" "nut-service"
			exit 1
		}
		config_get statepath "$section" statepath "$NUT_BASE_STATEPATH"
		ret=$?

		if [ -n "$statepath" ]; then
			printf "%s" "$statepath"
		elif [ "$ret" != "0" ]; then
			exit $ret
		else
			exit 1
		fi
	) || return $?
}

# Store user under which to run daemon processes
# shellcheck disable=SC2329
find_runas() {
	local section="$1"
	local package="$2"
	local fallback_runas="$3"
	local runas ret

	# Subshell so as not to interfere with main config_load
	(
		config_load "$package" || {
			log_config_load_error "$package" "nut-service.sh" "nut-service"
			exit 1
		}
		config_get runas "$section" runas "${fallback_runas:-nut}"
		ret=$?

		if [ -z "$runas" ]; then
			if [ "$ret" != "0" ]; then
				exit $ret
			else
				exit 1
			fi
		fi

		if [ -n "$(id -un "$runas")" ]; then
			printf "%s" "$runas"
		else
			# We omit the output on stderr to avoid potential mixing with the intended printf output on stdout,
			# when called via command substitution, while maintaining log output to syslog
			log_error "User '$runas' specified for 'runas' does not exist." nut-service.sh nut-service 2>/dev/null
			exit 1
		fi
	) || return $?
}

# Detect if service is running under procd, with no instances
# (e.g. upsd with no UPS drivers running)
service_active_no_instances() {
	local service="$1"
	local active_instances
	local active_var service_filter

	check_safe_uci_name "$service" || return 1

	service_filter="@['""${service}""']"
	active_instances="$(_procd_ubus_call list "{\"name\":\"$service\"}" | jsonfilter -l 1 -e active_var="$service_filter")"
	# If we get no output at all, the service is not running
	[ -z "$active_instances" ] && return 1

	case "$active_instances" in
	export\ active_var=*\;\ )
		active_var="${active_instances#export active_var=}"
		active_var="${active_var%%; }"
		;;
	*)
		log_error "Unexpected value '$active_instances' for 'active_instances' from jsonfilter in service_active_no_instances" nut-service.sh nut-service
		return 1
		;;
	esac

	# active_var is only empty, but present, if there are no instances for the service
	[ -z "$active_var" ] && return 0

	return 1
}

# Setup triggers in procd for changes to specified network interfaces
add_interface_triggers() {
	local section="$1"
	local interface_reload_delay="${2:-$DEFAULT_PROCD_INTERFACE_RELOAD_DELAY}"
	local initscript="$3"
	if [ $# -ge 3 ]; then
		shift 3
	fi

	local interfaces interface trigger_failed

	config_get interfaces "$section" triggerlist

	if [ -n "$interfaces" ] && [ "$interfaces" != "all" ]; then
		set -f
		trigger_failed="false"
		# interfaces is deliberately unquoted so we get word-splitting for
		# the for loop
		for interface in $interfaces; do
			# We use the variadic third and fourth parameters of procd_add_interface_trigger to
			# restart instead of reload on interface up/down events. Additionally the variadic
			# fifth and following parameters of procd_add_interface_trigger are passed through to
			# the <script>, so the trigger action becomes e.g. /etc/init.d/<script> restart <variadic_vars>.
			procd_add_interface_trigger "interface.*.up" "$interface" "/etc/init.d/$initscript" "restart" "$@" || trigger_failed="true"
		done
		set +f
		if [ "$trigger_failed" = "true" ]; then
			return 1
		fi
	elif [ "$interfaces" = "all" ]; then
		# Add a restart trigger on any interface's up status changing
		procd_add_raw_trigger "interface.*.up" "$interface_reload_delay" "/etc/init.d/$initscript" "restart" "$@" || return 1
	else
		return 0 # don't react to interface status
	fi
	return 0
}

# availability of network_is_up depends on /lib/functions/network.sh having
# been sourced
check_interface_up() {
	local section="$1"
	local interfaces interface have_up_interface

	config_get interfaces "$section" triggerlist

	if [ -n "$interfaces" ] && [ "$interfaces" != "all" ]; then
		set -f
		have_up_interface="false"
		for interface in $interfaces; do
			network_is_up "$interface" && have_up_interface="true" && break
		done
		set +f
		if [ "$have_up_interface" = "false" ]; then
			log_msg "None of the trigger interfaces are up." "nut-service.sh" "nut-service" "notice"
			return 1
		fi
	elif [ "$interfaces" = "all" ]; then
		# Return true if any interface is up
		# -q for jsonfilter only suppress error output, not messages on
		# stdout, redirect to >/dev/null is needed to avoid all output
		if ubus -S call network.device status | jsonfilter -q -l 1 -e '$[@.up=true].up' >/dev/null; then
			return 0
		fi
		log_msg "No interfaces are up." "nut-service.sh" "nut-service" "notice"
		return 1
	else
		return 0 # don't depend on interface status
	fi
	return 0
}