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

# Common 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

# We use explicit return 0 at the end of functions throughout, except where they
# would be dead code, for clarity

# Preserve current umask in CUR_UMASK, unless a umask was previously captured
CUR_UMASK="${CUR_UMASK:-$(umask)}"

restore_umask() {
	umask "$CUR_UMASK"
}

restore_umask_on_exit() {
	# Restore umask on exit
	# shellcheck disable=SC3047
	trap restore_umask EXIT
}

# Check string to contain only characters allowed in an UCI section name
check_safe_uci_name() {
	local val="$1"
	[ -n "$val" ] || return 1
	case "$val" in
	*[!a-zA-Z0-9_-]*)
		return 1
		;;
	esac
	return 0
}

# Check string to contain only characters valid in a RFC822 Date header
check_safe_date() {
	local in_date="$1"
	[ -n "$in_date" ] || return 1
	# Some AI code reviewers get confused by \(\) and \space in the case
	# pattern, but this is correct for busybox ash in modern OpenWrt
	# and does not allow \ through the validation.
	# We want to allow space, comma, and hyphen as they can all appear in an
	# RFC822 Date: header
	case "$in_date" in
	*[!a-zA-Z0-9_:+\(\),\ -]*)
		return 1
		;;
	esac
	return 0
}

# Check if input is a valid user or group name
check_valid_user_group_name() {
	local in_name="$1"
	case "$in_name" in
	[a-zA-Z_][a-zA-Z0-9_-]*) ;;
	# Includes the case of an empty string
	*)
		return 1
		;;
	esac
	return 0
}

# Just a check for safe/allowed characters, not a full validation
check_safe_hostname_or_ip() {
	local hostname="$1"

	case "$hostname" in
	"" | *[!a-zA-Z0-9.:-\[\]-]*)
		return 1
		;;
	esac
	return 0
}

# shellcheck disable=SC2329,SC2317
check_valid_hex_number() {
	local number="$1"
	local max_length="$2"
	[ -n "$max_length" ] || max_length=4
	case "$number" in
	'')
		# Empty string is not valid
		return 1
		;;
	0x*)
		case "$number" in
		0x[!0-9a-fA-F]*)
			return 1
			;;
		0x[0-9a-fA-F]*)
			# Minimum of 1 hex digit
			# Has a max of 4 hex digits (1-max_length hex digits allowed) and min of 1
			if [ "${#number}" -gt "$((max_length + 2))" ] || [ "${#number}" -lt 1 ]; then
				return 1
			fi
			return 0
			;;
		*)
			# Redundant, but add clarity for reviewers, especially automated
			# ones that can get confused without it.
			return 1
			;;
		esac
		;;
	*[!0-9a-fA-F]*)
		return 1
		;;
	*)
		# Has a maximum of 4 hex digits (1-max_length hex digits allowed)
		if [ "${#number}" -gt "$max_length" ]; then
			return 1
		fi
		return 0
		;;
	esac
	# We do not return 0 here as it is unnecessary (all case branches, including
	# catch-all have a return) and shellcheck will complain if we do.
}

# also passes on an empty value
check_signed_int() {
	local number="$1"

	# a minus sign with no number is invalid
	if [ "$number" = "-" ]; then
		return 1
	fi

	case "${number#[-]}" in
	*[!0123456789]*)
		return 1
		;;
	*)
		return 0
		;;
	esac
}

# also passes on an empty value
check_unsigned_int() {
	local number="$1"

	case "$number" in
	*[!0123456789]*)
		return 1
		;;
	*)
		return 0
		;;
	esac
}

# check for valid port, if present
# also passes on an empty value
check_port() {
	local port="$1"

	if [ -n "$port" ]; then
		case "$port" in
		*[!0-9]*)
			return 1
			;;
		esac
		# Catches port numbers outside valid range (1-65535)
		if [ "$port" -lt 1 ] || [ "$port" -gt 65535 ]; then
			return 1
		fi
	fi
	return 0
}

# Wrap logging, in case we decide to update the logging, everywhere
log_msg() {
	local reason="$1"
	local current_script="$2"
	local syslog_id="$3"
	local level="${4:-notice}"
	local facility="${5:-daemon}"

	logger -s -t "$syslog_id" -p "${facility}.${level}" "'$reason' in '$current_script'" || {
		# We use 'tr' as changing case via variable parameter substitution is not available in ash on OpenWrt
		# shellcheck disable=SC2018,SC2019
		level="$(echo "$level" | tr 'a-z' 'A-Z')"
		printf "'%s': Logging failed during $level: '%s' in '%s'\n" "$syslog_id" "$reason" "$current_script" >&2
	}
	case "$level" in
	crit)
		exit 1
		;;
	err | error | warn)
		return 1
		;;
	*)
		return 0
		;;
	esac
}

log_source_error() {
	local sourced_script="$1"
	local current_script="$2"
	local syslog_id="$3"
	log_msg "Unable to source '$sourced_script'" "$current_script" "$syslog_id" "crit"
}

log_config_load_error() {
	local config="$1"
	local current_script="$2"
	local syslog_id="$3"

	log_msg "Unable to load configuration '$config'" "$current_script" "$syslog_id" "crit"
}

# Wrap logging of errors, in case we decide to update the logging, everywhere
# we do error logging with script exit
log_error_exit() {
	local reason="$1"
	local current_script="$2"
	local syslog_id="$3"

	log_msg "$reason" "$current_script" "$syslog_id" "crit"
}

# Wrap logging of errors, in case we decide to update the logging, everywhere
# we do error logging without hard exit
log_error() {
	local reason="$1"
	local current_script="$2"
	local syslog_id="$3"

	log_msg "$reason" "$current_script" "$syslog_id" "error"
}

note_section_match() {
	local section="$1"
	local wanted="$2"

	if [ -n "$section" ] && [ "$section" = "$wanted" ]; then
		have_expected_section="true"
	fi
}

have_section_named() {
	local section_type="$1"
	local section_name="$2"
	local ret

	# 'pseudo-global' to capture result from config_foreach
	local have_expected_section="false"
	config_foreach note_section_match "$section_type" "$section_name"
	ret=$?

	if [ "$have_expected_section" = "true" ]; then
		return 0
	fi

	if [ "$ret" = "0" ]; then
		return 1
	else
		return $ret
	fi
}