#!/bin/bash
# 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; version 2 of the License.
#
# 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.

m4_include(lib/common.sh)

shopt -s nullglob

makepkg_args='-s --noconfirm -L'
repack=false
update_first=false
clean_first=false
install_pkg=
add_to_db=false
run_namcap=false
temp_chroot=false
chrootdir=
passeddir=
declare -a install_pkgs
declare -i ret=0

copy=$USER
[[ -n $SUDO_USER ]] && copy=$SUDO_USER
[[ -z "$copy" || $copy = root ]] && copy=copy
src_owner=${SUDO_USER:-$USER}

usage() {
	echo "Usage: ${0##*/} [options] -r <chrootdir> [--] [makepkg args]"
	echo ' Run this script in a PKGBUILD dir to build a package inside a'
	echo ' clean chroot. All unrecognized arguments passed to this script'
	echo ' will be passed to makepkg.'
	echo ''
	echo ' The chroot dir consists of the following directories:'
	echo ' <chrootdir>/{root, copy} but only "root" is required'
	echo ' by default. The working copy will be created as needed'
	echo ''
	echo 'The chroot "root" directory must be created via the following'
	echo 'command:'
	echo '    mkarchroot <chrootdir>/root base-devel'
	echo ''
	echo "Default makepkg args: $makepkg_args"
	echo ''
	echo 'Flags:'
	echo '-h         This help'
	echo '-c         Clean the chroot before building'
	echo '-u         Update the working copy of the chroot before building'
	echo '           This is useful for rebuilds without dirtying the pristine'
	echo '           chroot'
	echo '-d         Add the package to a local db at /repo after building'
	echo '-r <dir>   The chroot dir to use'
	echo '-I <pkg>   Install a package into the working copy of the chroot'
	echo '-l <copy>  The directory to use as the working copy of the chroot'
	echo '           Useful for maintaining multiple copies'
	echo "           Default: $copy"
	echo '-n         Run namcap on the package'
	echo '-T         Build in a temporary directory'
	exit 1
}

while getopts 'hcudr:I:l:nT' arg; do
	case "$arg" in
		h) usage ;;
		c) clean_first=true ;;
		u) update_first=true ;;
		d) add_to_db=true ;;
		r) passeddir="$OPTARG" ;;
		I) install_pkgs+=("$OPTARG") ;;
		l) copy="$OPTARG" ;;
		n) run_namcap=true; makepkg_args="$makepkg_args -i" ;;
		T) temp_chroot=true; copy+="-$RANDOM" ;;
		*) makepkg_args="$makepkg_args -$arg $OPTARG" ;;
	esac
done

# Canonicalize chrootdir, getting rid of trailing /
chrootdir=$(readlink -e "$passeddir")

if [[ ${copy:0:1} = / ]]; then
	copydir=$copy
else
	copydir="$chrootdir/$copy"
fi

# Pass all arguments after -- right to makepkg
makepkg_args="$makepkg_args ${*:$OPTIND}"

# See if -R was passed to makepkg
for arg in ${*:$OPTIND}; do
	if [[ $arg = -R ]]; then
		repack=true
		break
	fi
done

if (( EUID )); then
	die 'This script must be run as root.'
fi

if [[ ! -f PKGBUILD && -z "${install_pkgs[*]}" ]]; then
	die 'This must be run in a directory containing a PKGBUILD.'
fi

if [[ ! -d $chrootdir ]]; then
	die "No chroot dir defined, or invalid path '$passeddir'"
fi

if [[ ! -d $chrootdir/root ]]; then
	die "Missing chroot dir root directory. Try using: mkarchroot $chrootdir/root base-devel"
fi

umask 0022

# Detect chrootdir filesystem type
chroottype=$(stat -f -c %T "$chrootdir")

# Lock the chroot we want to use. We'll keep this lock until we exit.
# Note this is the same FD number as in mkarchroot
exec 9>"$copydir.lock"
if ! flock -n 9; then
	stat_busy "Locking chroot copy [$copy]"
	flock 9
	stat_done
fi

if [[ ! -d $copydir ]] || $clean_first; then
	# Get a read lock on the root chroot to make
	# sure we don't clone a half-updated chroot
	exec 8>"$chrootdir/root.lock"

	if ! flock -sn 8; then
		stat_busy "Locking clean chroot"
		flock -s 8
		stat_done
	fi

	stat_busy "Creating clean working copy [$copy]"
	if [[ "$chroottype" == btrfs ]]; then
		if [[ -d $copydir ]]; then
			btrfs subvolume delete "$copydir" >/dev/null ||
				die "Unable to delete subvolume $copydir"
		fi
		btrfs subvolume snapshot "$chrootdir/root" "$copydir" >/dev/null ||
			die "Unable to create subvolume $copydir"
	else
		mkdir -p "$copydir"
		rsync -a --delete -q -W -x "$chrootdir/root/" "$copydir"
	fi
	stat_done

	# Drop the read lock again
	exec 8>&-
fi

if [[ -n "${install_pkgs[*]}" ]]; then
	for install_pkg in "${install_pkgs[@]}"; do
		pkgname="${install_pkg##*/}"
		cp "$install_pkg" "$copydir/$pkgname"

		arch-nspawn "$copydir" pacman -U /$pkgname --noconfirm
		(( ret += !! $? ))

		rm "$copydir/$pkgname"
	done

	# If there is no PKGBUILD we have done
	[[ -f PKGBUILD ]] || exit $ret
fi

$update_first && arch-nspawn "$copydir" pacman -Syu --noconfirm

mkdir -p "$copydir/build"

# Remove anything in there UNLESS -R (repack) was passed to makepkg
$repack || rm -rf "$copydir"/build/*

# Read .makepkg.conf and .gnupg/pubring.gpg even if called via sudo
if [[ -n $SUDO_USER ]]; then
	SUDO_HOME="$(eval echo ~$SUDO_USER)"
	makepkg_conf="$SUDO_HOME/.makepkg.conf"
	if [[ -r "$SUDO_HOME/.gnupg/pubring.gpg" ]]; then
		install -D "$SUDO_HOME/.gnupg/pubring.gpg" "$copydir/build/.gnupg/pubring.gpg"
	fi
else
	makepkg_conf="$HOME/.makepkg.conf"
	if [[ -r "$HOME/.gnupg/pubring.gpg" ]]; then
		install -D "$HOME/.gnupg/pubring.gpg" "$copydir/build/.gnupg/pubring.gpg"
	fi
fi

# Get SRC/PKGDEST from makepkg.conf
if [[ -f $makepkg_conf ]]; then
	eval $(grep '^SRCDEST=' "$makepkg_conf")
	eval $(grep '^PKGDEST=' "$makepkg_conf")
	eval $(grep '^MAKEFLAGS=' "$makepkg_conf")
	eval $(grep '^PACKAGER=' "$makepkg_conf")
fi

[[ -z $SRCDEST ]] && eval $(grep '^SRCDEST=' /etc/makepkg.conf)
[[ -z $PKGDEST ]] && eval $(grep '^PKGDEST=' /etc/makepkg.conf)
[[ -z $MAKEFLAGS ]] && eval $(grep '^MAKEFLAGS=' /etc/makepkg.conf)
[[ -z $PACKAGER ]] && eval $(grep '^PACKAGER=' /etc/makepkg.conf)

# Use PKGBUILD directory if PKGDEST or SRCDEST don't exist
[[ -d $PKGDEST ]] || PKGDEST=.
[[ -d $SRCDEST ]] || SRCDEST=.

mkdir -p "$copydir/pkgdest"
if ! grep -q 'PKGDEST="/pkgdest"' "$copydir/etc/makepkg.conf"; then
	echo 'PKGDEST="/pkgdest"' >> "$copydir/etc/makepkg.conf"
fi

mkdir -p "$copydir/srcdest"
if ! grep -q 'SRCDEST="/srcdest"' "$copydir/etc/makepkg.conf"; then
	echo 'SRCDEST="/srcdest"' >> "$copydir/etc/makepkg.conf"
fi

if [[ -n $MAKEFLAGS ]]; then
	sed -i '/^MAKEFLAGS=/d' "$copydir/etc/makepkg.conf"
	echo "MAKEFLAGS='${MAKEFLAGS}'" >> "$copydir/etc/makepkg.conf"
fi

if [[ -n $PACKAGER ]]; then
	sed -i '/^PACKAGER=/d' "$copydir/etc/makepkg.conf"
	echo "PACKAGER='${PACKAGER}'" >> "$copydir/etc/makepkg.conf"
fi

# Set target CARCH as it might be used within the PKGBUILD to select correct sources
eval $(grep '^CARCH=' "$copydir/etc/makepkg.conf")
export CARCH

# Copy PKGBUILD and sources
cp PKGBUILD "$copydir/build/"
(
	source PKGBUILD
	for file in "${source[@]}"; do
		file="${file%%::*}"
		file="${file##*://*/}"
		if [[ -f $file ]]; then
			cp "$file" "$copydir/srcdest/"
		elif [[ -f $SRCDEST/$file ]]; then
			cp "$SRCDEST/$file" "$copydir/srcdest/"
		fi
	done

	# Find all changelog and install files, even inside functions
	for i in 'changelog' 'install'; do
		while read -r file; do
			# evaluate any bash variables used
			eval file=\"$(sed 's/^\(['\''"]\)\(.*\)\1$/\2/' <<< "$file")\"
			[[ -f $file ]] && cp "$file" "$copydir/build/"
		done < <(sed -n "s/^[[:space:]]*$i=//p" PKGBUILD)
	done
)

chown -R nobody "$copydir"/{build,pkgdest,srcdest}

cat > "$copydir/etc/sudoers.d/nobody-pacman" <<EOF
Defaults env_keep += "HOME"
nobody ALL = NOPASSWD: /usr/bin/pacman
EOF
chmod 440 "$copydir/etc/sudoers.d/nobody-pacman"

# This is a little gross, but this way the script is recreated every time in the
# working copy
cat >"$copydir/chrootbuild" <<EOF
#!/bin/bash
. /etc/profile
export HOME=/build

cd /build
sudo -u nobody makepkg $makepkg_args || exit 1

if $run_namcap; then
	pacman -S --needed --noconfirm namcap
	for pkgfile in /build/PKGBUILD /pkgdest/*.pkg.tar.?z; do
		echo "Checking \${pkgfile##*/}"
		sudo -u nobody namcap "\$pkgfile" 2>&1 | tee "/build/\${pkgfile##*/}-namcap.log"
	done
fi

exit 0
EOF
chmod +x "$copydir/chrootbuild"

if arch-nspawn "$copydir" /chrootbuild; then
	for pkgfile in "$copydir"/pkgdest/*.pkg.tar.?z; do
		if $add_to_db; then
			mkdir -p "$copydir/repo"
			pushd "$copydir/repo" >/dev/null
			cp "$pkgfile" .
			repo-add repo.db.tar.gz "${pkgfile##*/}"
			popd >/dev/null
		fi

		chown "$src_owner" "$pkgfile"
		mv "$pkgfile" "$PKGDEST"
	done

	for l in "$copydir"/build/*-{build,check,namcap,package,package_*}.log; do
		chown "$src_owner" "$l"
		[[ -f $l ]] && mv "$l" .
	done
else
	# Just in case. We returned 1, make sure we fail
	ret=1
fi

for f in "$copydir"/srcdest/*; do
	chown "$src_owner" "$f"
	mv "$f" "$SRCDEST"
done

if $temp_chroot; then
	stat_busy "Removing temporary directoy [$copy]"
	if [[ "$chroottype" == btrfs ]]; then
		btrfs subvolume delete "$copydir" >/dev/null ||
			die "Unable to delete subvolume $copydir"
	else
		# avoid change of filesystem in case of an umount failure
		rm --recursive --force --one-file-system "$copydir" ||
			die "Unable to delete $copydir"
	fi
	# remove lock file
	rm --force "$copydir.lock"
	stat_done
elif (( ret != 0 )); then
	die "Build failed, check $copydir/build"
else
	true
fi
