build/lib/functions/general/hash-files.sh

#!/usr/bin/env bash
#
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (c) 2013-2023 Igor Pecovnik, igor@armbian.com
#
# This file is a part of the Armbian Build Framework
# https://github.com/armbian/build/

function calculate_hash_for_all_files_in_dirs() {
	declare -a dirs_to_hash=("$@")
	declare -a files_to_hash=()
	for dir in "${dirs_to_hash[@]}"; do
		# skip if dir doesn't exist...
		if [[ ! -d "${dir}" ]]; then
			display_alert "calculate_hash_for_all_files_in_dirs" "skipping non-existent dir \"${dir}\"" "debug"
			continue
		fi
		mapfile -t files_in_dir < <(find -L "${dir}" -type f)
		if [[ ${#files_in_dir[@]} -eq 0 ]]; then
			display_alert "calculate_hash_for_all_files_in_dirs" "empty dir \"${dir}\"" "debug"
			continue
		fi
		files_to_hash+=("${files_in_dir[@]}")
	done

	calculate_hash_for_files "${files_to_hash[@]}"
}

# helper for artifacts that use "bash hash", eg, most of them.
function calculate_hash_for_bash_deb_artifact() {
	# the same as calculate_hash_for_files, but:
	# - each param is automatically prefixed with "${SRC}/lib/functions" if it does not start with a slash
	# - "compilation/packages/utils-dpkgdeb.sh" is automatically added
	declare -a deb_bash_arr=()
	for one in "$@"; do
		# if the param does not start with a slash, prefix it with "${SRC}/lib/functions", for convenience
		if [[ "${one}" != /* ]]; then
			one="${SRC}/lib/functions/${one}"
		fi
		deb_bash_arr+=("${one}")
	done
	deb_bash_arr+=("${SRC}/lib/functions/compilation/packages/utils-dpkgdeb.sh")
	calculate_hash_for_files "${deb_bash_arr[@]}"
	return 0
}

function calculate_hash_for_files() {
	hash_files="undetermined" # outer scope

	# relativize the files to SRC
	declare -a files_to_hash=("$@")
	declare -a files_to_hash_relativized=()
	for file in "${files_to_hash[@]}"; do
		# remove the SRC/ from the file name
		file="${file#${SRC}/}"
		files_to_hash_relativized+=("${file}")
	done

	# sort the array files_to_hash; use sort and readfile
	declare -a files_to_hash_sorted
	mapfile -t files_to_hash_sorted < <(for one in "${files_to_hash_relativized[@]}"; do echo "${one}"; done | LC_ALL=C sort -h) # "human" sorting

	display_alert "calculate_hash_for_files:" "files_to_hash_sorted: ${files_to_hash_sorted[*]}" "debug"

	# if the array is empty, then there is nothing to hash. return 16 zeros
	if [[ ${#files_to_hash_sorted[@]} -eq 0 ]]; then
		display_alert "calculate_hash_for_files:" "files_to_hash_sorted is empty" "debug"
		hash_files="0000000000000000"
		return 0
	fi

	declare full_hash
	full_hash="$(cd "${SRC}" && sha256sum "${files_to_hash_sorted[@]}")"
	hash_files="$(echo "${full_hash}" | sha256sum | cut -d' ' -f1)" # hash of hashes
	hash_files="${hash_files:0:16}"                                 # shorten it to 16 characters

	if [[ "${SHOW_DEBUG}" == "yes" ]]; then
		display_alert "Hash for files:" "$hash_files" "debug"
		display_alert "Full hash input for files:" "\n${full_hash}\n" "debug"
	fi
}

# helper, not strictly about files, but about functions. still hashing, though. outer scope: declare hash_functions="undetermined"
function calculate_hash_for_function_bodies() {
	declare -a function_bodies=()
	for func in "$@"; do
		# skip if function doesn't exist...
		if [[ $(type -t "${func}") != function ]]; then
			continue
		fi
		function_bodies+=("$(declare -f "${func}")")
	done

	if [[ ${#function_bodies[@]} -eq 0 ]]; then
		hash_functions="0000000000000000"
	else
		hash_functions="$(echo "${function_bodies[@]}" | sha256sum | cut -d' ' -f1)"
	fi
	return 0
}

# helper, for calculating hash of variables.
# such variables might contain paths, so we need to relativize them to SRC.
# outer scope: declare hash_variables="undetermined"
function calculate_hash_for_variables() {
	hash_variables="undetermined" # outer scope
	declare -a values_to_hash=("$@")

	declare all_values="${values_to_hash[*]}" # expand...
	declare all_values_pre_normalize="${all_values}"
	if [[ "${do_normalize_src_path:-"yes"}" == "yes" ]]; then
		all_values="${all_values//${SRC}/}" # remove all occurences of ${SRC} from all_values
	fi

	hash_variables="$(echo "${all_values}" | sha256sum | cut -d' ' -f1)" # outer scope
	display_alert "calculate_hash_for_variables all_values_pre_normalize" "${all_values_pre_normalize}" "debug"
	if [[ "${do_normalize_src_path:-"yes"}" == "yes" ]]; then
		display_alert "calculate_hash_for_variables               normalized" "${all_values}" "debug"
	else
		display_alert "calculate_hash_for_variables               normalized?" "no" "debug"
	fi
	display_alert "calculate_hash_for_variables hashed" "${hash_variables}" "debug"

	return 0
}