prepare-sample-configuration

#!/usr/bin/env sh
# This file is part of libertine. It is subject to the licence terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/libertine-linux/libertine/master/COPYRIGHT. No part of libertine, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
# Copyright © 2016-2018 The developers of libertine. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/libertine-linux/libertine/master/COPYRIGHT.


set -e
set -u
set -f

program_name="prepare-sample-configuration"

_program_path_find()
{
	if [ "${0%/*}" = "$0" ]; then

		# We've been invoked by the interpreter as, say, bash program
		if [ -r "$0" ]; then
			pwd -P
		# Clutching at straws; probably run via a download, anonymous script, etc, weird execve, etc
		else
			printf '\n'
		fi

	else

		# We've been invoked with a relative or absolute path (also when invoked via PATH in a shell)

		_program_path_find_parentPath()
		{
			parentPath="${scriptPath%/*}"
			if [ -z "$parentPath" ]; then
				parentPath='/'
			fi
			cd "$parentPath" 1>/dev/null
		}

		# pdksh / mksh have problems with unsetting a variable that was never set...
		if [ "${CDPATH+set}" = 'set' ]; then
			unset CDPATH
		fi

		if command -v realpath 1>/dev/null 2>/dev/null; then
			(
				scriptPath="$(realpath "$0")"

				_program_path_find_parentPath
				pwd -P
			)
		elif command -v readlink 1>/dev/null 2>/dev/null; then
			(
				local recursionDepth=0
				_program_path_resolve_symlinks_recursively()
				{
					local unresolvedPath="$1"
					
					recursionDepth=$((recursionDepth + 1))
					
					if [ $recursionDepth -gt 10 ]; then
						printf '%s\n' 'Recursion to depths greater than 10 is not allowed when resolving links.'
						return 1
					fi
					
					local potentialLinkDestination="$(readlink -- "$unresolvedPath")"
					
					if [ -z "$potentialLinkDestination" ]; then
						scriptPath="$unresolvedPath"
						return 0
					fi
					local linkDestination="$potentialLinkDestination"
					local parentFolderPath="${unresolvedPath%/*}"
					
					if [ "$parentFolderPath" = "$unresolvedPath" ]; then
						_program_path_resolve_symlinks_recursively "$linkDestination"
					else
						case "$linkDestination" in
														
							/*)
								_program_path_resolve_symlinks_recursively "$linkDestination"
							;;
							
							*)
								_program_path_resolve_symlinks_recursively "$parentFolderPath"/"$linkDestination"
							;;
							
						esac
					fi
				}

				scriptPath="$0"
				_program_path_resolve_symlinks_recursively "$scriptPath"

				_program_path_find_parentPath
				pwd -P
			)
		else
			# This approach will fail in corner cases where the script itself is a symlink in a path not parallel with the concrete script
			(
				scriptPath="$0"

				_program_path_find_parentPath
				pwd -P
			)
		fi

	fi
}

fail()
{
	local exitCode="$1"
	local message="$2"
	
	printf '%s:FAIL:%s\n' "$program_name" "$message" 1>&2
	exit $exitCode
}

depends()
{
	local binary
	for binary in "$@"
	do
		if ! command -v "$binary" 1>/dev/null 2>/dev/null; then
			local EX_OSFILE=72
			fail $EX_OSFILE "The binary `$binary` is not on the PATH"
		fi
	done
}

prepare_sample_configuration_createSshKeyPair()
{
	local keyPairType="$1"
	
	case "$keyPairType" in
		
		dsa)
			set -- -b 1024
		;;

		rsa)
			set -- -b 4096
		;;
		
		ecdsa)
			set -- -b 521
		;;
		
		ed25519)
			set --
		;;
		
	esac

	local keyFilePath=sample-configuration/machines/example/settings/initramfs/etc/ssh/"ssh_host_${keyPairType}_key"

	if [ -s "$keyFilePath" ]; then
		return 0
	fi

	if ! command -v ssh-keygen 1>/dev/null 2>/dev/null; then
		printf '%s\n' "Could not generate host key pair for $keyPairType for the example machine as 'ssh-keygen' is not in the PATH; please it in machines/example/settings/initramfs/etc/ssh/ssh_host_${keyPairType}_key and ssh_host_${keyPairType}_key.pub"
		return 0
	fi

	umask 077
	set +e
		IFS= ssh-keygen -q "$@" -t "$keyPairType" -N '' -C "$keyPairType host key for sample-configuration 'example' machine (in sample-configuration/machines)" -f "$keyFilePath"
	set -e
	
	if [ $? -ne 0 ]; then
		printf '%s\n' "Could not generate a $keyPairType host key pair for the sample-configuration 'example' machine using 'ssh-keygen'; please create it in machines/example/settings/initramfs/etc/ssh/ssh_host_${keyPairType}_key and ssh_host_${keyPairType}_key.pub"
	fi
}

depends git
prepare_sample_configuration_main()
{
	cd "$(_program_path_find)" 1>/dev/null 2>/dev/null
	
	local keyPairType
	for keyPairType in rsa ecdsa ed25519
	do
		prepare_sample_configuration_createSshKeyPair "$keyPairType"
	done

	if [ ! -d sample-configuration/packages/.git ]; then
		git -C sample-configuration clone --depth 1 --recurse-submodules https://github.com/libertine-linux/packages
	fi

	sample-configuration/packages/checkout-submodules-to-master
}

prepare_sample_configuration_main "$@"