makechrootpkg: Have functions be more function-y.

Rather than them simply being named blocks of code with braces around
them.

That is: have them take things via arguments rather than global
variables.

Specific notes:

 - download_sources:

   Observation: if $SUDO_USER is set, then src_owner=$SUDO_USER.

   So (for clarity), rather than checking if $SUDO_USER is set, check
   if $src_owner is different than $USER.

   This reduces how much we have to worry about global state.

 - install_packages:

    1. Receive the list of packages as arguments, rather than a global
       variable.
    2. Make the caller responsible for looking at PKGBUILD.  From the
       name and arguments, one would never expect it to look at PKGBUILD.

 - create_chroot->sync_chroot:

   I pulled the `if [[ ! -d $copydir ]] || $clean_first;` check out; it is
   now the caller's responsibility to use that check when deciding if to
   call sync_chroot.

1 files changed, 99 insertions, 36 deletions

diff --git a/makechrootpkg.in b/makechrootpkg.in
index e88b6e1..cdc3a93 100644
--- a/makechrootpkg.in
+++ b/makechrootpkg.in
@@ -70,6 +70,14 @@ usage() {
 }
 
 # {{{ functions
+# Usage: load_vars $makepkg_conf
+# Globals:
+#  - SRCDEST
+#  - SRCPKGDEST
+#  - PKGDEST
+#  - LOGDEST
+#  - MAKEFLAGS
+#  - PACKAGER
 load_vars() {
 	local makepkg_conf="$1" var
 
@@ -171,39 +179,56 @@ btrfs_subvolume_delete() {
 	btrfs subvolume delete "$dir"
 }
 
-create_chroot() {
-	# 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 ]] || $clean_first; then
-		# Get a read lock on the root chroot to make
-		# sure we don't clone a half-updated chroot
-		slock 8 "$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
+# Usage: sync_chroot $CHROOTDIR/$CHROOT <$CHROOTCOPY|$copydir>
+# Globals:
+#  - chroottype
+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
 
-		# Drop the read lock again
-		lock_close 8
+	# 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"
 }
 
-clean_temporary() {
+# Usage: delete_chroot $copydir
+# Globals:
+#  - chroottype
+delete_chroot() {
+	local copydir=$1
+
 	stat_busy "Removing chroot copy [%s]" "$copydir"
 	if [[ "$chroottype" == btrfs ]] && ! mountpoint -q "$copydir"; then
 		btrfs_subvolume_delete "$copydir" >/dev/null ||
@@ -219,7 +244,11 @@ clean_temporary() {
 	stat_done
 }
 
+# Usage: install_packages $copydir $pkgs...
 install_packages() {
+	local copydir=$1
+	local install_pkgs=("${@:2}")
+
 	local -a pkgnames
 	local ret
 
@@ -231,11 +260,19 @@ install_packages() {
 	ret=$?
 	rm -- "${pkgnames[@]/#/$copydir/root/}"
 
-	# If there is no PKGBUILD we are done
-	[[ -f PKGBUILD ]] || exit $ret
+	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}"
@@ -301,13 +338,20 @@ _chrootnamcap() {
 	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 [[ -n $SUDO_USER ]]; then
-		sudo -u $SUDO_USER env SRCDEST="$SRCDEST" BUILDDIR="$builddir" \
+	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="$builddir"
@@ -320,12 +364,21 @@ download_sources() {
 	rm -rf "$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"
 	done
 
+	local l
 	for l in "$copydir"/logdest/*; do
 		[[ $l == */logpipe.* ]] && continue
 		chown "$src_owner" "$l"
@@ -404,17 +457,27 @@ load_vars /etc/makepkg.conf
 [[ -d $SRCPKGDEST ]] || SRCPKGDEST=$PWD
 [[ -d $LOGDEST ]]    || LOGDEST=$PWD
 
-create_chroot
+# 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
 
-[[ -n ${install_pkgs[*]} ]] && install_packages
+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
+download_sources "$copydir" "$src_owner"
 
-prepare_chroot
+prepare_chroot "$copydir" "$USER_HOME" "$repack"
 
 if arch-nspawn "$copydir" \
 	--bind="$PWD:/startdir" \
@@ -422,12 +485,12 @@ if arch-nspawn "$copydir" \
 	"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
 	/chrootbuild "${makepkg_args[@]}"
 then
-	move_products
+	move_products "$copydir" "$src_owner"
 else
 	(( ret += 1 ))
 fi
 
-$temp_chroot && clean_temporary
+$temp_chroot && delete_chroot "$copydir"
 
 if (( ret != 0 )); then
 	if $temp_chroot; then