pmaports-rtwo/extra-repos/systemd/postmarketos-base-systemd/rootfs-usr-libexec-systemd-apk-trigger

#!/bin/sh
# shellcheck disable=SC3043
#
# This is meant to be called by an apk trigger. By splitting the logic out
# into a new script, one can easily modify/test/debug this logic without having
# to rebuild the package that installs it.

# NOTE: this variable, when set, is also used to indicate test mode
SYSTEMD_APK_ROOT="${SYSTEMD_APK_ROOT:-}"
UNIT_LIST_PATH="$SYSTEMD_APK_ROOT/var/lib/systemd-apk/installed.units"

remove_unit_symlinks() {
	local unit_path="$1"
	local search_dir
	local found_broken

	# Determine which config directory to search
	case "$unit_path" in
		*/systemd/system/*)
			search_dir="$SYSTEMD_APK_ROOT/etc/systemd/system"
			;;
		*/systemd/user/*)
			search_dir="$SYSTEMD_APK_ROOT/etc/systemd/user"
			;;
		*)
			return
			;;
	esac

	[ -d "$search_dir" ] || return 0

	# Keep removing broken symlinks until none remain
	while true; do
		found_broken=false
		symlinks=$(busybox find "$search_dir" -type l)

		while IFS= read -r symlink; do
			[ -z "$symlink" ] && continue
			target=$(readlink "$symlink")
			# Resolve relative paths to absolute paths
			if [ "${target#/}" = "$target" ]; then
				# Relative path - resolve from symlink directory
				abs_target=$(cd "$(dirname "$symlink")" && realpath "$target" 2>/dev/null)
			else
				# Already absolute
				abs_target="$target"
			fi

			if [ "$abs_target" = "$unit_path" ]; then
				echo "Removing dangling symlink: $symlink -> $target"
				rm -vf "$symlink"
				found_broken=true
			fi
		done <<-EOF
		$symlinks
		EOF
		[ "$found_broken" = "false" ] && break
	done
}

parse_diff_output() {
	local diff_output="$1"
	local added_var="$2"
	local removed_var="$3"
	# Note: use an underscore here to reduce the chances that $added_var and
	# $removed_car are set to the variable names here:
	local _added_paths=""
	local _removed_paths=""

	# Using heredoc to process lines and avoid a subshell, see SC2031
	while IFS= read -r line; do
		line_without_prefix=${line#?}
		path=${line_without_prefix%% *}
		case "$line" in
			*'type=dir'*)
				# Skip directories
				continue;;
			-[!-]*)
				_removed_paths="$_removed_paths $path"
				;;
			+[!+]*)
				_added_paths="$_added_paths $path"
				;;
			*)
	            ;;
		esac
	done <<-EOF
	$diff_output
	EOF

    # Set results in caller's variables
    if [ -n "$added_var" ]; then eval "$added_var=\"$_added_paths\""; fi
    if [ -n "$removed_var" ]; then eval "$removed_var=\"$_removed_paths\""; fi
}

run_systemctl() {
	local args="$*"

	if [ -n "$SYSTEMD_APK_ROOT" ]; then
		# Print what we'd run, when in 'test' mode
		echo "systemctl $args"
	else
		# shellcheck disable=SC2086
		systemctl $args
	fi
}

trigger_systemd_presets() {
	local added_paths="$1"
	local removed_paths="$2"
	local system_units_to_preset=""
	local user_units_to_preset=""

	# Process added paths for presets, skip if also removed (modified files)
	for path in $added_paths; do
	    if echo " $removed_paths " | grep -qF " $path "; then
	        continue
	    fi

		case "$path" in
			*/systemd/system/*)
				if [ -f "$path" ] && grep -qE "^\[Install\]" "$path" 2>/dev/null; then
					system_units_to_preset="$system_units_to_preset $(basename "$path")"
				fi
				;;
			*/systemd/user/*)
				if [ -f "$path" ] && grep -qE "^\[Install\]" "$path" 2>/dev/null; then
					user_units_to_preset="$user_units_to_preset $(basename "$path")"
				fi
				;;
		esac
	done

	# Apply presets to newly added units
	if [ -n "$system_units_to_preset" ]; then
		echo "Applying presets to new system units..."
		for unit in $system_units_to_preset; do
		    run_systemctl --no-reload preset "$unit"
		done
	else
		echo "No new system units to preset"
	fi

	if [ -n "$user_units_to_preset" ]; then
		echo "Applying presets to new user units..."
		for unit in $user_units_to_preset; do
			run_systemctl --no-reload preset --global "$unit"
		done
	else
		echo "No new user units to preset"
	fi

}

handle_unit_changes() {
	mkdir -p "$(dirname "$UNIT_LIST_PATH")"

	local current_units="${UNIT_LIST_PATH}.new"
	local removed_paths=""
	local added_paths=""

	# Create current state
	treescan /usr/lib/systemd/system > "$current_units"
	treescan /usr/lib/systemd/user >> "$current_units"

	# Ensure previous state file exists (create empty if missing)
	[ -f "$UNIT_LIST_PATH" ] || touch "$UNIT_LIST_PATH"

	diff_output=$(busybox diff "$UNIT_LIST_PATH" "$current_units")
	parse_diff_output "$diff_output" "added_paths" "removed_paths"

	# Clean up symlinks for truly removed units (removed but not re-added)
	for path in $removed_paths; do
		echo " $added_paths " | grep -qF " $path " && continue

		case "$path" in
			*/systemd/system/*|*/systemd/user/*)
				remove_unit_symlinks "$path"
				;;
		esac
	done

	trigger_systemd_presets "$added_paths" "$removed_paths"

	# Update stored state
	mv "$current_units" "$UNIT_LIST_PATH"
}

# If is set, then we're unit testing the trigger and don't actually want to run the rest of the stuff below
if [ -z "$SYSTEMD_APK_ROOT" ]; then
	handle_unit_changes
	exit 0
fi