1 files changed, 93 insertions, 0 deletions
diff --git a/debian/apt.auto-removal.sh b/debian/apt.auto-removal.sh
new file mode 100644
index 000000000..4ada56556
--- /dev/null
+++ b/debian/apt.auto-removal.sh
@@ -0,0 +1,93 @@
+#!/bin/sh
+
+set -e
+
+# Author: Steve Langasek <steve.langasek@canonical.com>
+#
+# Mark as not-for-autoremoval those kernel packages that are:
+#  - the currently booted version
+#  - the kernel version we've been called for
+#  - the latest kernel version (determined using rules copied from the grub
+#    package for deciding which kernel to boot)
+#  - the second-latest kernel version, if the booted kernel version is
+#    already the latest and this script is called for that same version,
+#    to ensure a fallback remains available in the event the newly-installed
+#    kernel at this ABI fails to boot
+# In the common case, this results in exactly two kernels saved, but it can
+# result in three kernels being saved.  It's better to err on the side of
+# saving too many kernels than saving too few.
+#
+# We generate this list and save it to /etc/apt/apt.conf.d instead of marking
+# packages in the database because this runs from a postinst script, and apt
+# will overwrite the db when it exits.
+
+
+eval $(apt-config shell APT_CONF_D Dir::Etc::parts/d)
+test -n "${APT_CONF_D}" || APT_CONF_D="/etc/apt/apt.conf.d"
+config_file=${APT_CONF_D}/01autoremove-kernels
+
+eval $(apt-config shell DPKG Dir::bin::dpkg/f)
+test -n "$DPKG" || DPKG="/usr/bin/dpkg"
+
+installed_version="$1"
+running_version="$(uname -r)"
+
+
+version_test_gt ()
+{
+	local version_test_gt_sedexp="s/[._-]\(pre\|rc\|test\|git\|old\|trunk\)/~\1/g"
+	local version_a="`echo "$1" | sed -e "$version_test_gt_sedexp"`"
+	local version_b="`echo "$2" | sed -e "$version_test_gt_sedexp"`"
+	$DPKG --compare-versions "$version_a" gt "$version_b"
+	return "$?"
+}
+
+list=$(${DPKG} -l 'linux-image-[0-9]*'|awk '/^ii/ { print $2 }' | sed -e's/linux-image-//')
+
+latest_version=""
+previous_version=""
+for i in $list; do
+	if version_test_gt "$i" "$latest_version"; then
+		previous_version="$latest_version"
+		latest_version="$i"
+	elif version_test_gt "$i" "$previous_version"; then
+		previous_version="$i"
+	fi
+done
+
+if [ "$latest_version" != "$installed_version" ] \
+   || [ "$latest_version" != "$running_version" ] \
+   || [ "$installed_version" != "$running_version" ]
+then
+	# We have at least two kernels that we have reason to think the
+	# user wants, so don't save the second-newest version.
+	previous_version=
+fi
+
+kernels=$(sort -u <<EOF
+$latest_version
+$installed_version
+$running_version
+$previous_version
+EOF
+)
+
+cat > "$config_file".dpkg-new <<EOF
+// File autogenerated by $0, do not edit
+APT
+{
+  NeverAutoRemove
+  {
+EOF
+for kernel in $kernels; do
+	echo "    \"^linux-image-${kernel}$\";" >> "$config_file".dpkg-new
+	echo "    \"^linux-image-extra-${kernel}$\";" >> "$config_file".dpkg-new
+	echo "    \"^linux-signed-image-${kernel}$\";" >> "$config_file".dpkg-new
+	echo "    \"^linux-backports-modules-.*-${kernel}$\";" >> "$config_file".dpkg-new
+	echo "    \"^linux-headers-${kernel}$\";" >> "$config_file".dpkg-new
+done
+cat >> "$config_file".dpkg-new <<EOF
+  };
+};
+EOF
+mv "$config_file".dpkg-new "$config_file"