#!/bin/sh
# shellcheck disable=SC3043

set -e

# Does what add-shell/remove-shell does, with the sync extras from
# update-shells, but does not add the link targets, only the lines
# listed; more safety checking; no regex escape issue; in contrast
# to the debianutils ones, it honours the admin’s choice disabling
# lines by commenting them, as in prefixing a single hash sign.
mogrifyshells() {
	local basefile="$DPKG_ROOT/etc/shells"
	local tmpa="$basefile.tmp"
	local tmpb="$basefile.tmp2"
	local rc=0 x mode='' oshf=$-
	set +e

	case $basefile in
	(/*)
		;;
	(*)
		echo >&2 "E: mogrifyshells: invalid DPKG_ROOT: $DPKG_ROOT"
		exit 1 ;;
	esac

	(
		set -o noclobber
		cat "$basefile" >"$tmpa"
	) || {
		cat >&2 <<-EOF
			E: add-shell/remove-shell is currently running or was previously interrupted
			I: Please examine ${tmpa} to see if it should be moved onto ${basefile}
		EOF
		exit 1
	}

	for x in "$@"; do
		case $x in
		(+) mode=+; continue ;;
		(-) mode=-; continue ;;
		esac
		case $mode in
		(+)
			grep -F -x -q -e "$x" -e "#$x" "$tmpa"
			rc=$?
			case $rc in
			(0)
				;;
			(1)
				printf '%s\n' "$x" >>"$tmpa"
				;;
			(*)
				echo >&2 "E: mogrifyshells: grep error $rc"
				rm -f "$tmpa"
				exit 1 ;;
			esac
			;;
		(-)
			grep -F -x -v -e "$x" -e "#$x" "$tmpa" >"$tmpb"
			rc=$?
			case $rc in
			(0|1)
				;;
			(*)
				echo >&2 "E: mogrifyshells: grep error $rc"
				rm -f "$tmpa" "$tmpb"
				exit 1 ;;
			esac
			mv "$tmpb" "$tmpa" || {
				echo >&2 "E: mogrifyshells: mv error"
				rm -f "$tmpa" "$tmpb"
				exit 1
			}
			;;
		(*)
			echo >&2 'E: mogrifyshells: no mode given'
			rm -f "$tmpa"
			exit 1
			;;
		esac
	done

	rc=0
	chmod --reference="$basefile" "$tmpa" || {
		x=$(stat -c %a "$basefile") || rc=1
		chmod "0$x" "$tmpa" || rc=1
	}
	chown --reference="$basefile" "$tmpa" || {
		x=$(stat -c %u:%g "$basefile") || rc=1
		chown -- "$x" "$tmpa" || rc=1
	}
	sync -d -- "$tmpa" || rc=1
	test 0 = "$rc" || {
		echo >&2 'E: mogrifyshells: error during chmod/chown/fdatasync'
		rm -f "$tmpa"
		exit 1
	}
	mv -Z "$tmpa" "$basefile" || mv "$tmpa" "$basefile" || {
		echo >&2 "E: mogrifyshells: error during mv back; $tmpa left"
		exit 1  # but keep temporary
	}
	sync "$basefile" "${basefile%/*}" || {
		echo >&2 "W: mogrifyshells: error during final sync"
		# and pray
	}

	case $oshf in
	(*e*) set -e ;;
	esac
	return 0
}

# This maintainer script can be called the following ways:
#
# * prerm "remove"
# * old-prerm "upgrade" $new_version
# * conflictors-prerm "remove" "in-favour" $new_package $new_version
# * deconfigureds-prerm "deconfigure" "in-favour"
#	$package_being_installed $pbi_version		# new-package
#	["removing" $conflicting_package $cp_version]	# old-package
# The package and dependencies are at least Half-Installed; dependencies
# have previously been configured and not removed.
#
# * new-prerm "failed-upgrade" $old_version
# * new-prerm "failed-upgrade" $old_version $new_version # 1.18.5, stretch
# Called when 'old-prerm "upgrade"' fails; new package not unpacked, all
# other constraints the same as above.

case $1 in
(remove|deconfigure)
	update-alternatives --remove ksh /bin/mksh
	update-alternatives --remove ksh /bin/mksh-static
	# remove compatibility symlink if broken
	test '!' -h /usr/bin/ksh || test -e /usr/bin/ksh || rm -f /usr/bin/ksh

	# unadd us from /etc/shells; clean up old add-shell-caused damage
	# shellcheck disable=SC2046
	mogrifyshells - /bin/mksh /bin/mksh-static \
	    - /usr/bin/mksh /usr/bin/mksh-static \
	    - $(for x in \
		/usr/lib/klibc/bin \
		/usr/lib/diet/bin \
		/usr/lib/*-linux-musl*/bin \
	    ; do echo "$x/mksh" "$x/mksh-static"; done)
	;;

(upgrade|failed-upgrade)
	;;

(*)
	echo >&2 "E: prerm called with unknown subcommand '$1'"
	exit 1
	;;
esac

# dh_installdeb will replace this with shell code automatically
# generated by other debhelper scripts.



exit 0