path: root/makechrootpkg.in

#!/bin/bash
# License: GNU GPLv2
#
# 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

init_variables() {
	default_makepkg_args=(-s --noconfirm -L --holdver)
	makepkg_args=("${default_makepkg_args[@]}")
	repack=false
	update_first=false
	clean_first=false
	install_pkg=
	run_namcap=false
	temp_chroot=false
	chrootdir=
	passeddir=
	declare -a install_pkgs
	declare -i ret=0

	bindmounts_ro=()
	bindmounts_rw=()

	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. Arguments passed to this script after the'
	echo ' end-of-options marker (--) 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: ${default_makepkg_args[*]}"
	echo ''
	echo 'Flags:'
	echo '-h         This help'
	echo '-c         Clean the chroot before building'
	echo '-d <dir>   Bind directory into build chroot as read-write'
	echo '-D <dir>   Bind directory into build chroot as read-only'
	echo '-u         Update the working copy of the chroot before building'
	echo '           This is useful for rebuilds without dirtying the pristine'
	echo '           chroot'
	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
}

# {{{ functions
# Usage: load_vars $makepkg_conf
# Globals:
#  - SRCDEST
#  - SRCPKGDEST
#  - PKGDEST
#  - LOGDEST
#  - MAKEFLAGS
#  - PACKAGER
load_vars() {
	local makepkg_conf="$1" var

	[[ -f $makepkg_conf ]] || return 1

	for var in {SRC,SRCPKG,PKG,LOG}DEST MAKEFLAGS PACKAGER; do
		[[ -z ${!var:-} ]] && eval $(grep "^${var}=" "$makepkg_conf")
	done

	return 0
}

# Usage: btrfs_subvolume_id $SUBVOLUME
btrfs_subvolume_id() (
	set -o pipefail
	LC_ALL=C btrfs subvolume show "$1" | sed -n 's/^\tSubvolume ID:\s*//p'
)

# Usage: btrfs_subvolume_list_all $FILEPATH
#
# Given $FILEPATH somewhere on a mounted btrfs filesystem, print the
# ID and full path of every subvolume on the filesystem, one per line
# in the format "$ID $PATH", where $PATH is relative to the top-level
# subvolume (which might not be what is mounted).
#
# BUG: Due to limitations in the `btrfs` tool, this will not correctly
# list subvolumes whose path contains a space.
btrfs_subvolume_list_all() (
	set -o pipefail

	local mountpoint all
	mountpoint="$(df --output=target "$1" | sed 1d)" || return
	# The output of `btrfs subvolume list -a` is a space-separated
	# sequence of "key value key value...".  Unfortunately both
	# keys and values can contain space, and there's no escaping
	# or indication of when this happens.  So we assume
	#  1. ID is the first column
	#  2. That no key or value will contain " path"
	#  3. That the "path" value does not contain a space.
	all="$(LC_ALL=C btrfs subvolume list -a "$mountpoint" | sed -r 's|^ID ([0-9]+) .* path (<FS_TREE>/)?(\S*).*|\1 \3|')" || return

	# Sanity check the output
	local id path
	while read -r id path; do
		# ID should be numeric
		[[ "$id" =~ ^-?[0-9]+$ ]] || return
		# While a path could countain a space, the above code
		# doesn't support it; if there is space, then it means
		# we got a line not matching the expected format.
		[[ "$path" != *' '* ]] || return
	done <<<"$all"

	printf '%s\n' "$all"
)

# Usage: btrfs_subvolume_list $SUBVOLUME
#
# Assuming that $SUBVOLUME is a btrfs subvolume, list all child
# subvolumes; from most deeply nested to most shallowly nested.
#
# This is intended to be a sane version of `btrfs subvolume list`.
btrfs_subvolume_list() {
	local subvolume=$1

	local id all path subpath
	id="$(btrfs_subvolume_id "$subvolume")" || return
	all="$(btrfs_subvolume_list_all "$subvolume")" || return
	path=$(awk -v id="$id" '$1 == id { sub($1 FS, ""); print }' <<<"$all")
	while read -r id subpath; do
		if [[ "$subpath" = "$path"/* ]]; then
			printf '%s\n' "${subpath#"${path}/"}"
		fi
	done <<<"$all" | LC_ALL=C sort --reverse
}

# Usage: btrfs_subvolume_delete $SUBVOLUME
#
# Assuming that $SUBVOLUME is a btrfs subvolume, delete it and all
# subvolumes below it.
#
# This is intended to be a recursive version of
# `btrfs subvolume delete`.
btrfs_subvolume_delete() {
	local dir="$1"

	# We store the result as a variable because we want to see if
	# btrfs_subvolume_list fails or succeeds before we start
	# deleting things.  (Then we have to work around the subshell
	# trimming the trailing newlines.)
	local subvolumes
	subvolumes="$(btrfs_subvolume_list "$dir")" || return
	[[ -z "$subvolumes" ]] || subvolumes+=$'\n'

	local subvolume
	while read -r subvolume; do
		btrfs subvolume delete "$dir/$subvolume" || return
	done < <(printf '%s' "$subvolumes")

	btrfs subvolume delete "$dir"
}

# Usage: sync_chroot $CHROOTDIR/$CHROOT <$CHROOTCOPY|$copydir>
sync_chroot() {
	local chrootdir=$1
	local copy=$2
	local copydir=''
	if [[ ${copy:0:1} = / ]]; then
		copydir=$copy
	else
		copydir="$chrootdir/$copy"
	fi

	if [[ "$chrootdir/root" -ef "$copydir" ]]; then
		error 'Cannot sync copy with itself: %s' "$copydir"
		return 1
	fi

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

	# Get a read lock on the root chroot to make
	# sure we don't clone a half-updated chroot
	slock 8 "$chrootdir/root.lock" \
		"Locking clean chroot [%s]" "$chrootdir/root"

	stat_busy "Synchronizing chroot copy [%s] -> [%s]" "$chrootdir/root" "$copydir"
	if [[ "$chroottype" == btrfs ]] && ! mountpoint -q "$copydir"; then
		if [[ -d $copydir ]]; then
			btrfs_subvolume_delete "$copydir" >/dev/null ||
				die "Unable to delete subvolume %s" "$copydir"
		fi
		btrfs subvolume snapshot "$chrootdir/root" "$copydir" >/dev/null ||
			die "Unable to create subvolume %s" "$copydir"
	else
		mkdir -p "$copydir"
		rsync -a --delete -q -W -x "$chrootdir/root/" "$copydir"
	fi
	stat_done

	# Drop the read lock again
	lock_close 8

	# Update mtime
	touch "$copydir"
}

# Usage: delete_chroot $copydir
delete_chroot() {
	local copydir=$1
	# Detect chrootdir filesystem type
	local chroottype=$(stat -f -c %T "$copydir")

	stat_busy "Removing chroot copy [%s]" "$copydir"
	if [[ "$chroottype" == btrfs ]] && ! mountpoint -q "$copydir"; then
		btrfs_subvolume_delete "$copydir" >/dev/null ||
			die "Unable to delete subvolume %s" "$copydir"
	else
		# avoid change of filesystem in case of an umount failure
		rm --recursive --force --one-file-system "$copydir" ||
			die "Unable to delete %s" "$copydir"
	fi

	# remove lock file
	rm -f "$copydir.lock"
	stat_done
}

# Usage: install_packages $copydir $pkgs...
install_packages() {
	local copydir=$1
	local install_pkgs=("${@:2}")

	local -a pkgnames
	local ret

	pkgnames=("${install_pkgs[@]##*/}")

	cp -- "${install_pkgs[@]}" "$copydir/root/"
	arch-nspawn "$copydir" "${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
		pacman -U --noconfirm -- "${pkgnames[@]/#//root/}"
	ret=$?
	rm -- "${pkgnames[@]/#/$copydir/root/}"

	return $ret
}

# Usage: prepare_chroot $copydir $HOME $repack $run_namcap
# Globals:
#  - MAKEFLAGS
#  - PACKAGER
prepare_chroot() {
	local copydir=$1
	local USER_HOME=$2
	local repack=$3
	local run_namcap=$4

	$repack || rm -rf "$copydir/build"

	local builduser_uid="${SUDO_UID:-$UID}"
	local builduser_gid="$(id -g "$builduser_uid")"
	local install="install -o $builduser_uid -g $builduser_gid"
	local x

	# We can't use useradd without chrooting, otherwise it invokes PAM modules
	# which we might not be able to load (i.e. when building i686 packages on
	# an x86_64 host).
	sed -e '/^builduser:/d' -i "$copydir"/etc/{passwd,group}
	printf >>"$copydir/etc/group"  'builduser:x:%d:\n' $builduser_gid
	printf >>"$copydir/etc/passwd" 'builduser:x:%d:%d:builduser:/build:/bin/bash\n' $builduser_uid $builduser_gid

	$install -d "$copydir"/{build,build/.gnupg,startdir,{pkg,srcpkg,src,log}dest}

	for x in .gnupg/pubring.{kbx,gpg}; do
		[[ -r $USER_HOME/$x ]] || continue
		$install -m 644 "$USER_HOME/$x" "$copydir/build/$x"
	done

	sed -e '/^MAKEFLAGS=/d' -e '/^PACKAGER=/d' -i "$copydir/etc/makepkg.conf"
	for x in BUILDDIR=/build PKGDEST=/pkgdest SRCPKGDEST=/srcpkgdest SRCDEST=/srcdest LOGDEST=/logdest \
		"MAKEFLAGS='${MAKEFLAGS:-}'" "PACKAGER='${PACKAGER:-}'"
	do
		grep -q "^$x" "$copydir/etc/makepkg.conf" && continue
		echo "$x" >>"$copydir/etc/makepkg.conf"
	done

	cat > "$copydir/etc/sudoers.d/builduser-pacman" <<EOF
Defaults env_keep += "HOME"
builduser ALL = NOPASSWD: /usr/bin/pacman
EOF
	chmod 440 "$copydir/etc/sudoers.d/builduser-pacman"

	if ! grep -q '^\[repo\]' "$copydir/etc/pacman.conf"; then
		local line=$(grep -n '^\[' "$copydir/etc/pacman.conf" |grep -Fv ':[options]'|sed 's/:.*//;1q')
		local ins='[repo]
SigLevel = Optional TrustAll
Server = file:///repo
'
		sed -i "${line}i${ins//$'\n'/\\n}" "$copydir/etc/pacman.conf"
	fi
	# Avoid having to use `pacman -Sy` to update [repo], as
	# networking might be disabled inside of the chroot.
	cp "$copydir/repo/repo.db" "$copydir/var/lib/pacman/sync/repo.db"

	# This is a little gross, but this way the script is recreated every time in the
	# working copy
	{
		printf '#!/bin/bash\n'
		declare -f _chrootprepare
		printf '_chrootprepare "$@"\n'
	} > "$copydir/chrootprepare"
	chmod +x "$copydir/chrootprepare"
	{
		printf '#!/bin/bash\n'
		declare -f _chrootbuild
		printf '_chrootbuild "$@" || exit\n'

		if $run_namcap; then
			declare -f _chrootnamcap
			printf '_chrootnamcap || exit\n'
		fi
	} >"$copydir/chrootbuild"
	chmod +x "$copydir/chrootbuild"
}

# These functions aren't run in makechrootpkg,
# so no global variables
_chrootprepare() {
	. /etc/profile
	sudo -iu builduser bash -c 'cd /startdir; makepkg "$@" --nobuild' -bash "$@"
}

_chrootbuild() {
	. /etc/profile
	sudo -iu builduser bash -c 'cd /startdir; makepkg "$@" --noextract --noprepare' -bash "$@"
}

_chrootnamcap() {
	pacman -S --needed --noconfirm namcap
	for pkgfile in /startdir/PKGBUILD /pkgdest/*; do
		echo "Checking ${pkgfile##*/}"
		sudo -u builduser namcap "$pkgfile" 2>&1 | tee "/logdest/${pkgfile##*/}-namcap.log"
	done
}

# Usage: download_sources $copydir $src_owner
# Globals:
#  - SRCDEST
#  - USER
download_sources() {
	local copydir=$1
	local src_owner=$2

	local builddir="$(mktemp -d)"
	chmod 1777 "$builddir"

	# Ensure sources are downloaded
	if [[ $USER != $src_owner ]]; then
		sudo -u $src_owner env SRCDEST="$SRCDEST" BUILDDIR="$builddir" \
			makepkg --config="$copydir/etc/makepkg.conf" --verifysource -o
	else
		( export SRCDEST BUILDDIR="$builddir"
			makepkg --asroot --config="$copydir/etc/makepkg.conf" --verifysource -o
		)
	fi
	(( $? != 0 )) && die "Could not download sources."

	# Clean up garbage from verifysource
	rm -rf "$builddir"
}

# Usage: move_products $copydir $owner
# Globals:
#  - PKGDEST
#  - LOGDEST
move_products() {
	local copydir=$1
	local src_owner=$2

	local pkgfile
	for pkgfile in "$copydir"/pkgdest/*; do
		chown "$src_owner" "$pkgfile"
		mv "$pkgfile" "$PKGDEST"
		if [[ $PKGDEST != $PWD ]]; then
			ln -sf "$PKGDEST/${pkgfile##*/}" .
		fi
	done

	local l
	for l in "$copydir"/logdest/*; do
		[[ $l == */logpipe.* ]] && continue
		chown "$src_owner" "$l"
		mv "$l" "$LOGDEST"
	done

	for s in "$copydir"/srcpkgdest/*; do
		chown "$src_owner" "$s"
		mv "$s" "$SRCPKGDEST"
	done
}
# }}}

main() {
	init_variables

	orig_argv=("$@")

	while getopts 'hcur:I:l:nTD:d:' arg; do
		case "$arg" in
			c) clean_first=true ;;
			D) bindmounts_ro+=(--bind-ro="$OPTARG") ;;
			d) bindmounts_rw+=(--bind="$OPTARG") ;;
			u) update_first=true ;;
			r) passeddir="$OPTARG" ;;
			I) install_pkgs+=("$OPTARG") ;;
			l) copy="$OPTARG" ;;
			n) run_namcap=true; makepkg_args+=(-i) ;;
			T) temp_chroot=true; copy+="-$$" ;;
			h|*) usage ;;
		esac
	done

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

	check_root "$0" "${orig_argv[@]}"

	# Canonicalize chrootdir, getting rid of trailing /
	chrootdir=$(readlink -e "$passeddir")
	[[ ! -d $chrootdir ]] && die "No chroot dir defined, or invalid path '%s'" "$passeddir"
	[[ ! -d $chrootdir/root ]] && die "Missing chroot dir root directory. Try using: mkarchroot %s/root base-devel" "$chrootdir"

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

	# Pass all arguments after -- right to makepkg
	makepkg_args+=("${@:$OPTIND}")

	# See if -R was passed to makepkg
	for arg in "${@:OPTIND}"; do
		case ${arg%%=*} in
			-*R*|--repackage)
				repack=true
				break 2
				;;
		esac
	done

	if [[ -n $SUDO_USER ]]; then
		eval "USER_HOME=~$SUDO_USER"
	else
		USER_HOME=$HOME
	fi

	umask 0022

	load_vars "${XDG_CONFIG_HOME:-$USER_HOME/.config}/pacman/makepkg.conf" || load_vars "$USER_HOME/.makepkg.conf"
	load_vars /etc/makepkg.conf

	# Use PKGBUILD directory if these don't exist
	[[ -d $PKGDEST ]]    || PKGDEST=$PWD
	[[ -d $SRCDEST ]]    || SRCDEST=$PWD
	[[ -d $SRCPKGDEST ]] || SRCPKGDEST=$PWD
	[[ -d $LOGDEST ]]    || LOGDEST=$PWD

	# Lock the chroot we want to use. We'll keep this lock until we exit.
	lock 9 "$copydir.lock" "Locking chroot copy [%s]" "$copy"

	if [[ ! -d $copydir ]] || $clean_first; then
		sync_chroot "$chrootdir" "$copy"
	fi

	$update_first && arch-nspawn "$copydir" \
			"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
			pacman -Syu --noconfirm

	if [[ -n ${install_pkgs[*]:-} ]]; then
		install_packages "$copydir" "${install_pkgs[@]}"
		ret=$?
		# If there is no PKGBUILD we have done
		[[ -f PKGBUILD ]] || return $ret
	fi

	download_sources "$copydir" "$src_owner"

	prepare_chroot "$copydir" "$USER_HOME" "$repack"

	if arch-nspawn "$copydir" \
		--bind="$PWD:/startdir" \
		--bind="$SRCDEST:/srcdest" \
		"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
		/chrootprepare "${makepkg_args[@]}" &&
	   arch-nspawn "$copydir" \
		--bind="$PWD:/startdir" \
		--bind="$SRCDEST:/srcdest" \
		"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
		/chrootbuild "${makepkg_args[@]}"
	then
		move_products "$copydir" "$src_owner"
	else
		(( ret += 1 ))
	fi

	$temp_chroot && delete_chroot "$copydir"

	if (( ret != 0 )); then
		if $temp_chroot; then
			die "Build failed"
		else
			die "Build failed, check %s/build" "$copydir"
		fi
	else
		true
	fi
}

main "$@"