osi-mk: Implement --edit --size

1 files changed, 24 insertions, 1 deletions

diff --git a/osi-mk b/osi-mk
index d6ddd74..1d136b2 100755
--- a/osi-mk
+++ b/osi-mk
@@ -181,7 +181,30 @@ main() {
 						btrfstune -fu "$arg_file"
 					} |& sed "s|^|${prefix} |"
 				fi
-				# TODO: resize according to $arg_size
+				if [[ -n $arg_size ]]; then
+					# Calculate sizes in exact bytes now, to avoid any discrepancies
+					# between truncate(1) and btrfs-filesystem(8).
+					tmpfile=$(mktemp -t -- "${0##*/}.XXXXXXXXXX")
+					trap "rm -- ${tmpfile@Q}" EXIT
+					truncate --reference="$arg_file" --size="$arg_size" -- "$tmpfile"
+					old_size=$(stat --format='%s' -- "$arg_file")
+					new_size=$(stat --format='%s' -- "$tmpfile")
+					rm -- "$tmpfile"
+					trap - EXIT
+
+					# Do the resize
+					arg_mountpoint=$(mktemp -dt -- "${0##*/}.XXXXXXXXXX")
+					trap "rmdir -- ${arg_mountpoint@Q}" EXIT
+					if (( new_size > old_size )); then
+						truncate --size="$new_size" -- "$arg_file"
+						sudo -- ./osi-mount --root -- "$arg_file" "$arg_mountpoint" btrfs filesystem resize max "$arg_mountpoint"
+					elif (( new_size < old_size )); then
+						sudo -- ./osi-mount --root -- "$arg_file" "$arg_mountpoint" btrfs filesystem resize "$new_size" "$arg_mountpoint"
+						truncate --size="$new_size" -- "$arg_file"
+					fi
+					rmdir -- "$arg_mountpoint" EXIT
+					trap - EXIT
+				fi
 			else
 				printf -v prefix "$(gettext -- '%s [format]')" "$NAME"
 				{