#!/bin/bash
#   makerepropkg - rebuild a package to see if it is reproducible
#
#   Copyright (c) 2019 by Eli Schwartz <eschwartz@archlinux.org>
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
#

#!/hint/bash
# This may be included with or without `set -euE`

# License: Unspecified

[[ -z ${_INCLUDE_COMMON_SH:-} ]] || return 0
_INCLUDE_COMMON_SH="$(set +o|grep nounset)"

set +u +o posix
# shellcheck disable=1091
. /usr/share/makepkg/util.sh
$_INCLUDE_COMMON_SH

# Avoid any encoding problems
export LANG=C

shopt -s extglob

# check if messages are to be printed using color
if [[ -t 2 && "$TERM" != dumb ]]; then
	colorize
else
	# shellcheck disable=2034
	declare -gr ALL_OFF='' BOLD='' BLUE='' GREEN='' RED='' YELLOW=''
fi

stat_busy() {
	local mesg=$1; shift
	# shellcheck disable=2059
	printf "${GREEN}==>${ALL_OFF}${BOLD} ${mesg}...${ALL_OFF}" "$@" >&2
}

stat_done() {
	# shellcheck disable=2059
	printf "${BOLD}done${ALL_OFF}\n" >&2
}

_setup_workdir=false
setup_workdir() {
	[[ -z ${WORKDIR:-} ]] && WORKDIR=$(mktemp -d --tmpdir "${0##*/}.XXXXXXXXXX")
	_setup_workdir=true
	trap 'trap_abort' INT QUIT TERM HUP
	trap 'trap_exit' EXIT
}

cleanup() {
	if [[ -n ${WORKDIR:-} ]] && $_setup_workdir; then
		rm -rf "$WORKDIR"
	fi
	exit "${1:-0}"
}

abort() {
	error 'Aborting...'
	cleanup 255
}

trap_abort() {
	trap - EXIT INT QUIT TERM HUP
	abort
}

trap_exit() {
	local r=$?
	trap - EXIT INT QUIT TERM HUP
	cleanup $r
}

die() {
	(( $# )) && error "$@"
	cleanup 255
}

##
#  usage : lock( $fd, $file, $message, [ $message_arguments... ] )
##
lock() {
	# Only reopen the FD if it wasn't handed to us
	if ! [[ "/dev/fd/$1" -ef "$2" ]]; then
		mkdir -p -- "$(dirname -- "$2")"
		eval "exec $1>"'"$2"'
	fi

	if ! flock -n "$1"; then
		stat_busy "${@:3}"
		flock "$1"
		stat_done
	fi
}

##
#  usage : slock( $fd, $file, $message, [ $message_arguments... ] )
##
slock() {
	# Only reopen the FD if it wasn't handed to us
	if ! [[ "/dev/fd/$1" -ef "$2" ]]; then
		mkdir -p -- "$(dirname -- "$2")"
		eval "exec $1>"'"$2"'
	fi

	if ! flock -sn "$1"; then
		stat_busy "${@:3}"
		flock -s "$1"
		stat_done
	fi
}

##
#  usage : lock_close( $fd )
##
lock_close() {
	local fd=$1
	# https://github.com/koalaman/shellcheck/issues/862
	# shellcheck disable=2034
	exec {fd}>&-
}

##
# usage: pkgver_equal( $pkgver1, $pkgver2 )
##
pkgver_equal() {
	if [[ $1 = *-* && $2 = *-* ]]; then
		# if both versions have a pkgrel, then they must be an exact match
		[[ $1 = "$2" ]]
	else
		# otherwise, trim any pkgrel and compare the bare version.
		[[ ${1%%-*} = "${2%%-*}" ]]
	fi
}

##
#  usage: find_cached_package( $pkgname, $pkgver, $arch )
#
#    $pkgver can be supplied with or without a pkgrel appended.
#    If not supplied, any pkgrel will be matched.
##
find_cached_package() {
	local searchdirs=("$PWD" "$PKGDEST") results=()
	local targetname=$1 targetver=$2 targetarch=$3
	local dir pkg pkgbasename name ver rel arch r results

	for dir in "${searchdirs[@]}"; do
		[[ -d $dir ]] || continue

		for pkg in "$dir"/*.pkg.tar?(.!(sig|*.*)); do
			[[ -f $pkg ]] || continue

			# avoid adding duplicates of the same inode
			for r in "${results[@]}"; do
				[[ $r -ef $pkg ]] && continue 2
			done

			# split apart package filename into parts
			pkgbasename=${pkg##*/}
			pkgbasename=${pkgbasename%.pkg.tar*}

			arch=${pkgbasename##*-}
			pkgbasename=${pkgbasename%-"$arch"}

			rel=${pkgbasename##*-}
			pkgbasename=${pkgbasename%-"$rel"}

			ver=${pkgbasename##*-}
			name=${pkgbasename%-"$ver"}

			if [[ $targetname = "$name" && $targetarch = "$arch" ]] &&
					pkgver_equal "$targetver" "$ver-$rel"; then
				results+=("$pkg")
			fi
		done
	done

	case ${#results[*]} in
		0)
			return 1
			;;
		1)
			printf '%s\n' "${results[0]}"
			return 0
			;;
		*)
			error 'Multiple packages found:'
			printf '\t%s\n' "${results[@]}" >&2
			return 1
	esac
}

#!/hint/bash
# License: Unspecified
:

# shellcheck disable=2034
CHROOT_VERSION='v4'

##
#  usage : check_root $keepenv
##
orig_argv=("${BASH_SOURCE[0]}" "$@")
check_root() {
	local keepenv=$1

	(( EUID == 0 )) && return
	if type -P sudo >/dev/null; then
		exec sudo --preserve-env=$keepenv -- "${orig_argv[@]}"
	else
		exec su root -c "$(printf ' %q' "${orig_argv[@]}")"
	fi
}

##
#  usage : is_btrfs( $path )
# return : whether $path is on a btrfs
##
is_btrfs() {
	[[ -e "$1" && "$(stat -f -c %T "$1")" == btrfs ]]
}

##
#  usage : is_subvolume( $path )
# return : whether $path is a the root of a btrfs subvolume (including
#          the top-level subvolume).
##
is_subvolume() {
	[[ -e "$1" && "$(stat -f -c %T "$1")" == btrfs && "$(stat -c %i "$1")" == 256 ]]
}

##
#  usage : subvolume_delete_recursive( $path )
#
#    Find all btrfs subvolumes under and including $path and delete them.
##
subvolume_delete_recursive() {
	local subvol

	is_subvolume "$1" || return 0

	while IFS= read -d $'\0' -r subvol; do
		if ! subvolume_delete_recursive "$subvol"; then
			return 1
		fi
	done < <(find "$1" -mindepth 1 -xdev -depth -inum 256 -print0)
	if ! btrfs subvolume delete "$1" &>/dev/null; then
		error "Unable to delete subvolume %s" "$subvol"
		return 1
	fi

	return 0
}


source /usr/share/makepkg/util/config.sh
source /usr/share/makepkg/util/message.sh

declare -A buildinfo
declare -a buildenv buildopts installed installpkgs

archiveurl='https://archive.archlinux.org/packages'
buildroot=/var/lib/archbuild/reproducible
chroot=testenv

parse_buildinfo() {
    local line var val

    while read -r line; do
        var="${line%% = *}"
        val="${line#* = }"
        case ${var} in
            buildenv)
                buildenv+=("${val}")
                ;;
            options)
                buildopts+=("${val}")
                ;;
            installed)
                installed+=("${val}")
                ;;
            *)
                buildinfo["${var}"]="${val}"
                ;;
        esac
    done
}

get_pkgfile() {
    local cdir=${cache_dirs[0]}
    local pkgfilebase=${1}
    local pkgname=${pkgfilebase%-*-*-*}
    local pkgfile ext

    for ext in .xz .zst ''; do
        pkgfile=${pkgfilebase}.pkg.tar${ext}

        for c in "${cache_dirs[@]}"; do
            if [[ -f ${c}/${pkgfile} ]]; then
                cdir=${c}
                break
            fi
        done

        for f in "${pkgfile}" "${pkgfile}.sig"; do
            if [[ ! -f "${cdir}/${f}" ]]; then
                msg2 "retrieving '%s'..." "${f}" >&2
                curl -Llf -# -o "${cdir}/${f}" "${archiveurl}/${pkgname:0:1}/${pkgname}/${f}" || continue 2
            fi
        done
        printf '%s\n' "file://${cdir}/${pkgfile}"
        return 0
    done

    return 1
}

usage() {
    cat << __EOF__
usage: ${BASH_SOURCE[0]##*/} [options] <package_file>

Run this script in a PKGBUILD dir to build a package inside a
clean chroot while attempting to reproduce it. The package file
will be used to derive metadata needed for reproducing the
package, including the .PKGINFO as well as the buildinfo.

For more details see https://reproducible-builds.org/

OPTIONS
    -c <dir>      Set pacman cache
    -M <file>     Location of a makepkg config file
    -h            Show this usage message
__EOF__
}

while getopts 'M:c:h' arg; do
        case "$arg" in
                M) archroot_args+=(-M "$OPTARG") ;;
                c) cache_dirs+=("$OPTARG") ;;
                h) usage; exit 0 ;;
                *|?) usage; exit 1 ;;
        esac
done
shift $((OPTIND - 1))

check_root

if [[ -n $1 ]]; then
    pkgfile="$1"
    if ! bsdtar -tqf "${pkgfile}" .BUILDINFO >/dev/null 2>&1; then
        error "file is not a valid pacman package: '%s'" "${pkgfile}"
        exit 1
    fi
else
    error "no package file specified. Try '${BASH_SOURCE[0]##*/} -h' for more information. "
    exit 1
fi

if (( ${#cache_dirs[@]} == 0 )); then
	mapfile -t cache_dirs < <(pacman-conf CacheDir)
fi

ORIG_HOME=${HOME}
IFS=: read -r _ _ _ _ _ HOME _ < <(getent passwd "${SUDO_USER:-$USER}")
load_makepkg_config
HOME=${ORIG_HOME}
[[ -d ${SRCDEST} ]] || SRCDEST=${PWD}

parse_buildinfo < <(bsdtar -xOqf "${pkgfile}" .BUILDINFO)
export SOURCE_DATE_EPOCH="${buildinfo[builddate]}"
PACKAGER="${buildinfo[packager]}"
BUILDDIR="${buildinfo[builddir]}"

# nuke and restore reproducible testenv
for copy in "${buildroot}"/*/; do
    [[ -d ${copy} ]] || continue
    subvolume_delete_recursive "${copy}"
done
rm -rf --one-file-system "${buildroot}"
(umask 0022; mkdir -p "${buildroot}")

for fname in "${installed[@]}"; do
    if ! allpkgfiles+=("$(get_pkgfile "${fname}")"); then
        error "failed to retrieve ${fname}"
        exit 1
    fi
done
printf '%s\n' "${allpkgfiles[@]}" | mkarchroot -U "${archroot_args[@]}" "${buildroot}"/root - || exit 1


# use makechrootpkg to prep the build directory
makechrootpkg -r "${buildroot}" -l "${chroot}" -- --packagelist || exit 1

# set detected makepkg.conf options
{
    for var in PACKAGER BUILDDIR; do
        printf '%s=%s\n' "${var}" "${!var@Q}"
    done
    printf 'OPTIONS=(%s)\n' "${buildopts[*]@Q}"
    printf 'BUILDENV=(%s)\n' "${buildenv[*]@Q}"
} >> "${buildroot}/${chroot}"/etc/makepkg.conf >> "${buildroot}/${chroot}"/etc/makepkg.conf
install -d -o "${SUDO_UID:-$UID}" -g "$(id -g "${SUDO_UID:-$UID}")" "${buildroot}/${chroot}/${BUILDDIR}"

# kick off the build
arch-nspawn "${buildroot}/${chroot}" \
    --bind="${PWD}:/startdir" \
    --bind="${SRCDEST}:/srcdest" \
    /chrootbuild -C --noconfirm --log --holdver --skipinteg

if (( $? == 0 )); then
    msg2 "built succeeded! built packages can be found in ${buildroot}/${chroot}/pkgdest"
    msg "comparing artifacts..."
    if cmp -s "${pkgfile}" "${buildroot}/${chroot}/pkgdest/${pkgfile##*/}"; then
        msg2 "Package successfully reproduced!"
        exit 0
    else
        warning "Package is not reproducible. :("
        sha256sum "${pkgfile}" "${buildroot}/${chroot}/pkgdest/${pkgfile##*/}"
    fi
fi

# the package either failed to build, or was unreproducible
exit 1
