ifupdown2: fixup maintainer scripts

Ticket: CM-5764
Reviewed By: TBA
Testing Done: of course none ;) Will update when I have some time to test

fupdown2's postinst and postrm scripts do not conform to Debian's policy
for maintainer scripts [1]. Specific non-conformance follows:

* fixed maintainer scripts so they only use /bin/sh as other shells are
  non-essential packages and may not exist on the system
* fixed maintainer scripts so only actions specified by $1 are performed
  per run of the script
* fixed maintainer scripts to only support specific values for $1, and
  will otherwise exit with error
* included at the bottom of the postrm script the "#DEBHELPER#" tag as
  during package building debianhelper will inject extra code at this
  location

[1] https://www.debian.org/doc/debian-policy/ch-maintainerscripts.html
(cherry picked from commit 2289fe4e90a0134fcb07fe7e2e838de755d73e68)

debian/python-ifupdown2.postinst

@@ -1,6 +1,22 @@
-#!/bin/bash
+#!/bin/sh
+# postinst script for ifupdown2
+#
+# see: dh_installdeb(1)
+
 set -e
 
+# summary of how this script can be called:
+#        * <postinst> `configure' <most-recently-configured-version>
+#        * <old-postinst> `abort-upgrade' <new version>
+#        * <conflictor's-postinst> `abort-remove' `in-favour' <package>
+#          <new-version>
+#        * <postinst> `abort-remove'
+#        * <deconfigured's-postinst> `abort-deconfigure' `in-favour'
+#          <failed-install-package> <version> `removing'
+#          <conflicting-package> <version>
+# for details, see http://www.debian.org/doc/debian-policy/ or
+# the debian-policy package
+
 MYNAME="${0##*/}"
 
 report() { echo "${MYNAME}: $*" ; }
@@ -17,7 +33,8 @@ case "$1" in
             ln -sf /run/network /etc/network/run
         fi
 
-        ln -sf /usr/share/python-ifupdown2/generate_interfaces.py /usr/share/doc/python-ifupdown2/examples/generate_interfaces.py
+        ln -sf /usr/share/python-ifupdown2/generate_interfaces.py \
+            /usr/share/doc/python-ifupdown2/examples/generate_interfaces.py
 
         [ -d /etc/network/if-pre-up.d ] || mkdir -p /etc/network/if-pre-up.d
         [ -d /etc/network/if-up.d ] || mkdir -p /etc/network/if-up.d
@@ -58,25 +75,29 @@ case "$1" in
         (cd /usr/share/man/man8/ && ln -sf /usr/share/man/man8/ifup.8.gz ifdown.8.gz)
 
         mkdir -p /etc/network/interfaces.d/
+        update-rc.d networking start 40 S . start 35 0 6 . >/dev/null
         ;;
 
-  purge)
+    abort-upgrade|abort-remove|abort-deconfigure)
-    # Note: We don't remove /etc/network/interfaces
+        ;;
-    rm -f /run/network/ifstate
+
-    rm -f /sbin/ifquery
+    *)
-    rm -f /sbin/ifup
+        echo "postinst called with unknown argument \`$1'" >&2
-    rm -f /sbin/ifdown
+        exit 1
-    rm -f /usr/share/doc/python-ifupdown2/generate_interfaces.py
         ;;
 esac
 
+# dh_installdeb will replace this with shell code automatically
+# generated by other debhelper scripts.
+
 # override default udev bridge and hotplug rules because they interfere with
 # networking init script
 udev_user_rulesdir=/etc/udev/rules.d/
 udev_sys_rulesdir=/lib/udev/rules.d/
 if [ -e $udev_user_rulesdir ]; then
-    udev_ifupdown2_overrides=("80-networking.rules" "60-bridge-network-interface.rules")
+    udev_ifupdown2_overrides="80-networking.rules
-    for u in ${udev_ifupdown2_overrides[*]}
+    60-bridge-network-interface.rules"
+    for u in ${udev_ifupdown2_overrides}
     do
         if [ -e ${udev_sys_rulesdir}/$u -a ! -e ${udev_user_rulesdir}/$u ]; then
             (cd ${udev_user_rulesdir} && ln -sf /dev/null $u)
@@ -84,10 +105,6 @@ if [ -e $udev_user_rulesdir ]; then
     done
 fi
 
-if [ -x "/etc/init.d/networking" ]; then
-    update-rc.d networking start 40 S . start 35 0 6 . >/dev/null || exit $?
-fi
-
 #DEBHELPER#
 
 exit 0

debian/python-ifupdown2.postrm

@@ -1,19 +1,56 @@
-#!/bin/bash
+#!/bin/sh
+# postrm script for ifupdown2
+#
+# see: dh_installdeb(1)
 
 set -e
 
-rm -f /sbin/ifup /sbin/ifdown /sbin/ifquery
+# summary of how this script can be called:
+#        * <postrm> `remove'
+#        * <postrm> `purge'
+#        * <old-postrm> `upgrade' <new-version>
+#        * <new-postrm> `failed-upgrade' <old-version>
+#        * <new-postrm> `abort-install'
+#        * <new-postrm> `abort-install' <old-version>
+#        * <new-postrm> `abort-upgrade' <old-version>
+#        * <disappearer's-postrm> `disappear' <overwriter>
+#          <overwriter-version>
+# for details, see http://www.debian.org/doc/debian-policy/ or
+# the debian-policy package
 
-case "$1" in
+postrm_remove()
-  purge)
+{
-    # Note: We don't remove /etc/network/interfaces
+	rm -f /sbin/ifup /sbin/ifdown /sbin/ifquery
+	update-rc.d networking remove >/dev/null
+}
+
+# Note: We don't remove /etc/network/interfaces
+postrm_purge()
+{
 	rm -f /var/tmp/network/ifstatenew
-
 	if [ -L /etc/network/run ] ; then
 		rm -f /etc/network/run
 	elif [ -d /etc/network/run ] ; then
 		rmdir --ignore-fail-on-non-empty /etc/network/run
 	fi
+}
+
+case "$1" in
+	purge)
+		postrm_purge
+	;;
+
+	remove)
+		postrm_remove
+	;;
+
+
+	upgrade|disappear|failed-upgrade|abort-install|abort-upgrade)
+	;;
+
+	*)
+		echo "postrm called with unknown argument \`$1'" >&2
+		exit 1
 	;;
 esac
 
@@ -22,6 +59,9 @@ udevlink=$(readlink /etc/udev/rules.d/80-networking.rules 2>/dev/null || true)
 udevlink=$(readlink /etc/udev/rules.d/60-bridge-network-interface.rules 2>/dev/null || true)
 [ -n "$udevlink" -a "$udevlink" == "/dev/null" ] && rm -f /etc/udev/rules.d/60-bridge-network-interface.rules
 
-if [ "$1" = "purge" ] ; then
+# dh_installdeb will replace this with shell code automatically
-    update-rc.d networking remove >/dev/null
+# generated by other debhelper scripts.
-fi
+
+#DEBHELPER#
+
+exit 0