#! /bin/bash -eu

# Maintain kernel-version-specific symlinks in /lib/firmware based on
# configuration present in /usr/share/microcode_ctl/ucode_with_caveats.
#
# SPDX-License-Identifier: CC0-1.0

usage()
{
	echo "Usage: update_ucode [--action {add|remove|refresh|list}]" \
	     "[--kernel KERNELVER]* [--verbose] [--dry-run]" \
	     "[--cleanup intel_ucode caveats_ucode]" \
	     "[--skip-common] [--skip-kernel-specific]" >&2
}

debug() { [ 0 = "$verbose" ] || echo "$*" >&2; }

MC_DIR=/usr/share/microcode_ctl
INTEL_UCODE_DIR=intel-ucode
DATA_DIR=/usr/share/microcode_ctl/ucode_with_caveats
FW_DIR=/lib/firmware
check_caveats=/usr/libexec/microcode_ctl/check_caveats

action=refresh
kernel=
verbose=0
verbose_opt=
dry_run=0
remove_cleanup=0
cleanup_intel=
cleanup_caveats=
skip_common=0
skip_caveats=0

while [ 1 -le "$#" ]; do
	case "$1" in
	-C|--skip-common)
		skip_common=1
		;;
	-K|--skip-kernel-specific)
		skip_caveats=1
		;;
	-a|--action)
		shift
		action="$1"
		;;
	-k|--kernel)
		shift
		kernel="$kernel $1"
		;;
	-v|--verbose)
		verbose=1
		verbose_opt="-v"
		;;
	-n|--dry-run)
		dry_run=1
		;;
	-c|--cleanup)
		remove_cleanup=1
		shift
		cleanup_intel="$1"
		shift
		cleanup_caveats="$1"
		;;
	*)
		echo "Unknown argument \"$1\"" >&2
		usage
		exit 1
	esac
	shift
done

cmd=
[ 0 -eq "$dry_run" ] || cmd=echo

case "$action" in
add|remove|refresh|list)
	# Scan all directories in FW_DIR and all existing kernels
	if [ -z "$kernel" ]; then
		debug "No kernel versions provided, scanning..."

		kvers=$(find /lib/modules/ -name '[2-9].*' -print)
		for k_dir in $kvers; do
			k="${k_dir#/lib/modules/}"
			[ ! -e "/boot/symvers-$k.gz" ] || {
				debug "  Adding $k (from /lib/modules)"
				kernel="$kernel $k"
			}
		done

		kvers=$(find /lib/firmware/ -name '[2-9].*' -print)
		for k_dir in $kvers; do
			k="${k_dir#/lib/firmware/}"
			[ ! -d "$k_dir" ] || {
				debug "  Adding $k (from /lib/firmware)"
				kernel="$kernel $k"
			}
		done

		kernel=$(printf "%s" "$kernel" | xargs -n 1 | sort -u)
	fi
	;;
*)
	echo "Unknown action \"$action\"" >&2
	usage
	exit 1
	;;
esac

# Generic part: managing intel ucode
debug "Running action \"$action\" on common Intel microcode directory"
while :; do
	[ 0 -eq "$skip_common" ] || break

	[ ! -e "/etc/microcode_ctl/intel-ucode-disallow" ] || {
		debug "  Skipping \"$i\":" \
		      "\"/etc/microcode_ctl/intel-ucode-disallow\"" \
		      "present"
		break
	}
	[ ! -e "$FW_DIR/intel-ucode-disallow" ] || {
		debug "  Found \"$FW_DIR/intel-ucode-disallow\"," \
		      "skipping"
		break
	}

	# Removing old files
	case "$action" in
	refresh|remove|list)
		debug "  Removing old files from ${FW_DIR}/${INTEL_UCODE_DIR}"
		if [ 0 = "$remove_cleanup" ]; then
			find "${MC_DIR}/${INTEL_UCODE_DIR}" \
				-maxdepth 1 -mindepth 1 \
				-type f -printf '%f\n'
		else
			cat "$cleanup_intel"
		fi | while read -r fname; do
			name="${FW_DIR}/${INTEL_UCODE_DIR}/${fname}"

			# Needed in case we downgrade to a version where
			# no symlinks in /lib/firmware were used
			if [ 1 = "$remove_cleanup" ]; then
				[ -L "$name" ] || continue
			fi

			[ "xlist" != "x$action" ] || {
				echo "$name"
				continue
			}

			$cmd rm -f $verbose_opt "$name"
		done
		[ "xlist" = "x$action" ] || {
			$cmd rmdir -p $verbose_opt \
				"${FW_DIR}/${INTEL_UCODE_DIR}" 2>/dev/null \
				|| true
		}
		;;
	esac

	# Adding new ones
	case "$action" in
	add|refresh)
		debug "  Creating symlinks in ${FW_DIR}/${INTEL_UCODE_DIR}"
		$cmd mkdir -p $verbose_opt "${FW_DIR}/${INTEL_UCODE_DIR}"
		$cmd find "${MC_DIR}/${INTEL_UCODE_DIR}" -maxdepth 1 -mindepth 1 \
			-type f -exec bash -c 'ln -s '"$verbose_opt"' '\''{}'\'' \
				"'"${FW_DIR}/${INTEL_UCODE_DIR}/"'$(basename '\''{}'\'')"' \;
		;;
	esac

	break
done

debug "Running action \"$action\" on kernels $kernel"

if [ 0 = "$remove_cleanup" ]; then
	ls "$DATA_DIR"
else
	cat "$cleanup_caveats"
fi | while read -r i; do
	[ 0 -eq "$skip_caveats" ] || break

	debug "Processing data directory \"$i\"..."

	for k in $(echo "$kernel"); do
		debug "    Processing kernel version \"$k\""
		{
			out=$($check_caveats -k "$k" -c "$i" $verbose_opt)
			ret="$?"
		} || :
		paths=$(printf "%s" "$out" | sed -n 's/^paths //p')
		ignore=$(printf "%s" "$out" | sed -n 's/^skip_cfgs //p')

		[ -z "$ignore" ] || {
			debug "      Configuration is ignored, skipping"
			continue
		}

		case "$action" in
		remove|refresh|list)
			[ "xlist" = "x$action" ] || \
				debug "    Removing \"$paths\" (part of $action)..."

			for p in $(printf "%s" "$paths"); do
				find "$DATA_DIR/$i" -path "$DATA_DIR/$i/$p" \
					-printf "%P\n"
			done | while read -r path; do
				[ -e "$FW_DIR/$k/readme-$i" ] || {
					debug "      \"$FW_DIR/$k/readme-$i\"" \
					      "is not found, skipping" \
					      "\"$paths\" removal"

					break
				}

				if [ "xlist" = "x$action" ]; then
					echo "$FW_DIR/$k/$path"
				else
					debug "      Removing \"$FW_DIR/$k/$path\""
					$cmd rm -f $verbose_opt "$FW_DIR/$k/$path"
					$cmd rmdir -p $verbose_opt \
						"$FW_DIR/$k/$(dirname $path)" 2>/dev/null \
						|| true
				fi
			done

			if [ -e "$FW_DIR/$k/readme-$i" ]; then
				if [ "xlist" = "x$action" ]; then
					echo "$FW_DIR/$k/readme-$i"
				else
					$cmd rm -f $verbose_opt \
						"$FW_DIR/$k/readme-$i"
					$cmd rmdir -p $verbose_opt \
						"$FW_DIR/$k" 2>/dev/null || true
				fi
			fi
			;;
		esac

		[ 0 -eq "$ret" ] || {
			debug "    Checking for caveats failed" \
			      "(kernel version \"$k\"), skipping"
			continue
		}

		[ -n "$paths" ] || {
			debug "    List of paths to add is empty, skipping"
			continue
		}

		case "$action" in
		add|refresh)
			debug "    Adding $paths (part of $action)..."

			[ -e "/boot/symvers-$k.gz" ] || {
				debug "      \"/boot/symvers-$k.gz\"" \
				      "does not exist, skipping"
				continue
			}

			for p in $(printf "%s" "$paths"); do
				find "$DATA_DIR/$i" -path "$DATA_DIR/$i/$p" \
					-printf "%P\n"
			done | while read -r path; do
				[ ! -e "$FW_DIR/$k/$path" ] || {
					debug "      $FW_DIR/$k/$path already" \
					      "exists, skipping"
					continue
				}

				debug "      Adding \"$FW_DIR/$k/$path\""
				$cmd mkdir -p $verbose_opt \
					"$(dirname "$FW_DIR/$k/$path")"
				$cmd ln -s $verbose_opt "$DATA_DIR/$i/$path" \
					"$FW_DIR/$k/$path"
			done

			if [ -e "$FW_DIR/$k/readme-$i" ]; then
				debug "        $FW_DIR/$k/readme-$i already" \
				      "exists, skipping creation"
			else
				$cmd cp $verbose_opt "$DATA_DIR/$i/readme" \
					"$FW_DIR/$k/readme-$i"
			fi
			;;
		remove)
		esac
	done
done