#!/bin/sh # SPDX-License-Identifier: GPL-2.0-or-later # Copyright 2021 Helmut Grohne <helmut@subdivi.de> # A "hashset" is a shell variable containing a sequence of elements separated # and surrounded by hash (#) characters. None of the elements may contain a # hash character. The character is thus chosen, because it initiates a comment # in /etc/shells. All variables ending in _SHELLS in this file are hashsets. set -e # Check whether hashset $1 contains element $2. hashset_contains() { case "$1" in *"#$2#"*) return 0 ;; *) return 1 ;; esac } log() { if [ "$VERBOSE" = 1 ]; then echo "$*" fi } ROOT= VERBOSE=0 NOACT=0 while [ $# -gt 0 ]; do case "$1" in --help) cat <<EOF usage: $0 [options] --no-act Do not move the actual update into place --verbose Be more verbose --root DIR Operate on the given chroot, defaults to / EOF exit 0 ;; --no-act) NOACT=1 ;; --root) shift if [ "$#" -lt 1 ]; then echo "missing argument to --root" 1>&2 exit 1 fi ROOT=$1 ;; --verbose) VERBOSE=1 ;; *) echo "unrecognized option $1" 1>&2 exit 1 ;; esac shift done PKG_DIR="$ROOT/usr/share/debianutils/shells.d" STATE_FILE="$ROOT/var/lib/shells.state" TARGET_ETC_FILE="$ROOT/etc/shells" SOURCE_ETC_FILE="$TARGET_ETC_FILE" NEW_ETC_FILE="$TARGET_ETC_FILE.tmp" NEW_STATE_FILE="$STATE_FILE.tmp" if ! test -e "$SOURCE_ETC_FILE"; then SOURCE_ETC_FILE="$ROOT/usr/share/debianutils/shells" fi PKG_SHELLS='#' LC_COLLATE=C.UTF-8 # glob in reproducible order for f in "$PKG_DIR/"*; do [ "$f" = "$PKG_DIR/*" ] && break while IFS='#' read -r line _; do [ -n "$line" ] || continue PKG_SHELLS="$PKG_SHELLS$line#" realshell=$(dpkg-realpath --root "$ROOT" "$line") if [ "$line" != "$realshell" ]; then PKG_SHELLS="$PKG_SHELLS$realshell#" fi done < "$f" done STATE_SHELLS='#' if [ -e "$STATE_FILE" ] ; then while IFS='#' read -r line _; do [ -n "$line" ] && STATE_SHELLS="$STATE_SHELLS$line#" done < "$STATE_FILE" fi cleanup() { rm -f "$NEW_ETC_FILE" "$NEW_STATE_FILE" } trap cleanup EXIT : > "$NEW_ETC_FILE" ETC_SHELLS='#' while IFS= read -r line; do shell=${line%%#*} # copy all comment lines, packaged shells and local additions if [ -z "$shell" ] || hashset_contains "$PKG_SHELLS" "$shell" || ! hashset_contains "$STATE_SHELLS" "$shell"; then echo "$line" >> "$NEW_ETC_FILE" ETC_SHELLS="$ETC_SHELLS$shell#" else log "removing shell $shell" fi done < "$SOURCE_ETC_FILE" : > "$NEW_STATE_FILE" saved_IFS=$IFS IFS='#' set -f # shellcheck disable=SC2086 # word splitting intended, globbing disabled set -- ${PKG_SHELLS###} set +f IFS=$saved_IFS for shell; do echo "$shell" >> "$NEW_STATE_FILE" # add shells that are neither already present nor locally removed if ! hashset_contains "$ETC_SHELLS" "$shell" && ! hashset_contains "$STATE_SHELLS" "$shell"; then echo "$shell" >> "$NEW_ETC_FILE" log "adding shell $shell" fi done if [ "$NOACT" = 0 ]; then if [ -e "$STATE_FILE" ]; then chmod --reference="${STATE_FILE}" "${NEW_STATE_FILE}" || chmod $(stat -c %a "${STATE_FILE}") "${NEW_STATE_FILE}" chown --reference="${STATE_FILE}" "${NEW_STATE_FILE}" || chown $(stat -c %U "${STATE_FILE}") "${NEW_STATE_FILE}" else chmod 0644 "$NEW_STATE_FILE" fi chmod --reference="${SOURCE_ETC_FILE}" "${NEW_ETC_FILE}" || chmod $(stat -c %a "${SOURCE_ETC_FILE}") "${NEW_ETC_FILE}" chown --reference="${SOURCE_ETC_FILE}" "${NEW_ETC_FILE}" || chown $(stat -c %U "${SOURCE_ETC_FILE}") "${NEW_ETC_FILE}" sync -d "$NEW_ETC_FILE" "$NEW_STATE_FILE" mv -Z "${NEW_ETC_FILE}" "${TARGET_ETC_FILE}" || mv "${NEW_ETC_FILE}" "${TARGET_ETC_FILE}" sync "$TARGET_ETC_FILE" sync "$(dirname "$TARGET_ETC_FILE")" mv "$NEW_STATE_FILE" "$STATE_FILE" sync "$STATE_FILE" sync "$(dirname "$STATE_FILE")" trap "" EXIT fi