use debconf to check if the plugdev group is necessary

packaging/debian/control

@@ -3,7 +3,7 @@ Section: misc
 Priority: optional
 Maintainer: Daniel Pavel <daniel.pavel@gmail.com>
 Build-Depends: debhelper (>= 8)
-Build-Depends-Indep: python
+Build-Depends-Indep: python, po-debconf
 X-Python-Version: >= 2.7
 X-Python3-Version: >= 3.2
 Standards-Version: 3.9.4
@@ -13,10 +13,10 @@ Vcs-browser: http://github.com/pwr/Solaar
 
 Package: solaar
 Architecture: all
-Depends: ${misc:Depends}, udev (>= 175), passwd | adduser,
+Depends: ${misc:Depends}, ${debconf:Depends}, udev (>= 175), passwd | adduser,
  ${python:Depends}, python-pyudev (>= 0.13), python-gi (>= 3.2), gir1.2-gtk-3.0 (>= 3.4),
  ${DesktopIconTheme}
-Recommends: gir1.2-notify-0.7
+Recommends: gir1.2-notify-0.7, consolekit (>= 0.4.3) | systemd (>= 44)
 Suggests: solaar-gnome3 (= ${source:Version})
 Description: Logitech Unifying Receiver peripherals manager for Linux
  Solaar is a Linux device manager for Logitech's Unifying Receiver peripherals.

packaging/debian/solaar.config

@@ -0,0 +1,62 @@
+#!/bin/sh
+set -e
+
+. /usr/share/debconf/confmodule
+db_version 2.0
+db_capb backup
+
+consolekit_running() {
+	test -e /var/run/ConsoleKit/database
+}
+
+systemd_running() {
+	test -e /sys/fs/cgroup/systemd
+}
+
+plugdev_group_exists() {
+	getent group plugdev >/dev/null
+}
+
+
+# if not reconfiguring, and the right daemons are running,
+# no reason to do anything
+if test -z "$DEBCONF_RECONFIGURE"; then
+	consolekit_running && exit 0
+	systemd_running && exit 0
+fi
+
+# if the package hasn't been configured yet, and no seat daemon is running,
+# change the default
+if ! db_get solaar/use_plugdev_group; then
+	if ! consolekit_running && ! systemd_running; then
+		plugdev_group_exists && db_set solaar/use_plugdev_group true
+		# if not reconfiguring, we have the right group and the right setting
+		# no need to ask anything
+		test -z "$DEBCONF_RECONFIGURE" && exit 0
+	fi
+fi
+
+# update the question template
+if consolekit_running; then
+	db_subst solaar/use_plugdev_group SEAT_DAEMON_STATUS "the ConsoleKit"
+elif systemd_running; then
+	db_subst solaar/use_plugdev_group SEAT_DAEMON_STATUS "the systemd"
+else
+	db_subst solaar/use_plugdev_group SEAT_DAEMON_STATUS "NEITHER"
+fi
+# ask the question
+db_input high solaar/use_plugdev_group
+db_go
+
+db_get solaar/use_plugdev_group
+if test "$RET" = true; then
+	# make sure the group exists
+	if ! plugdev_group_exists; then
+		groupadd --system plugdev || addgroup --system plugdev
+	fi
+	# reminder about plugdev membership
+	db_input high solaar/plugdev_membership
+	db_go
+fi
+
+exit 0

packaging/debian/solaar.postinst

@@ -1,12 +0,0 @@
-#!/bin/sh
-
-set -e
-
-# shamelessly copied from usbmuxd.postinst
-
-# creating plugdev group if it's not already present on the system
-if ! getent group plugdev >/dev/null; then
-	groupadd --system --force plugdev || addgroup --system plugdev
-fi
-
-#DEBHELPER#

packaging/debian/solaar.templates

@@ -0,0 +1,27 @@
+Template: solaar/use_plugdev_group
+Type: boolean
+Default: false
+Description: Use plugdev group?
+ By default, the Logitech receiver devices are only accessible by the root user.
+ .
+ To allow access to regular users (through solaar), the needed ACLs can be
+ applied, either by the ConsoleKit or systemd daemon, to the current seat
+ (logged-in user).
+ Right now, ${SEAT_DAEMON_STATUS} daemon is running.
+ .
+ If neither of these daemons is installed on your system, or you want to make
+ the receiver accessible to ssh users, members of the 'plugdev' system group
+ can be given access to the receiver devices.
+
+Template: solaar/plugdev_membership
+Type: note
+Description:
+ Don't forget to make sure all your desktop users are members of the plugdev
+ system group.
+ .
+ You can add new members to the group by running, as root:
+ .
+     gpasswd --add <username> plugdev
+ .
+ For the group membership to take effect, the affected users have to log-out
+ and log-in again.

packaging/debian/solaar.udev

@@ -0,0 +1,39 @@
+# Allows non-root users to have raw access the Logitech Unifying USB Receiver
+# device. For development purposes, allowing users to write to the receiver is
+# potentially dangerous (e.g. perform firmware updates).
+
+ACTION != "add", GOTO="solaar_end"
+SUBSYSTEM != "hidraw", GOTO="solaar_end"
+
+# Unifying receiver
+ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c52b", GOTO="solaar_apply"
+ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c532", GOTO="solaar_apply"
+
+# Nano receiver, "Unifying ready"
+ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c52f", GOTO="solaar_apply"
+
+GOTO="solaar_end"
+
+#
+#
+#
+LABEL="solaar_apply"
+
+# don't apply to the paired devices, just the receivers
+DRIVERS=="logitech-djdevice", GOTO="solaar_end"
+
+# if the package configuration does not want the plugdev group, don't change the
+# group and access mode
+PROGRAM="/usr/bin/debconf-show solaar", RESULT=="*use_plugdev_group: false*", GOTO="solaar_no_plugdev"
+MODE="0660", GROUP="plugdev"
+
+LABEL="solaar_no_plugdev"
+# tags for systemd/consolekit, they will apply the right ACLs for seated users
+TAG+="uaccess", TAG+="udev-acl"
+
+#
+#
+#
+
+LABEL="solaar_end"
+# vim: ft=udevrules