Build and load binder/ashmem kernel modules on service start

As both kernel modules are not part of the standard Ubuntu kernel we
need to build and load them at runtime. We bundle this together with
the container manager start and reuse the classic snap scripts to do
the actual build in a proper environment.

scripts/classic-create

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+set -eu
+
+ROOT=$SNAP_COMMON/classic
+
+if [ -d $ROOT ]; then
+    echo "classic already enabled"
+    exit 1
+fi
+
+if [ $(id -u) -ne 0 ]; then
+    echo "This script needs to be called as root" >&2
+    exit 1
+fi
+
+CORE=""
+if [ -e /snap/core/current ]; then
+    CORE="core"
+elif [ -e /snap/ubuntu-core/current ]; then
+    CORE="ubuntu-core"
+else
+    echo "Cannot find core snap"
+    exit 1
+fi
+
+# FIXME: confinement will prevent this
+echo "Creating classic environment"
+VERSION="$(/bin/readlink /snap/${CORE}/current)"
+SNAPROOT="/var/lib/snapd/snaps/${CORE}_${VERSION}.snap"
+/usr/bin/unsquashfs -d $ROOT $SNAPROOT
+mkdir $ROOT/snappy
+
+# enable
+sudo chroot $ROOT /var/lib/classic/enable.sh
+
+# copy important config
+for f in hostname timezone localtime; do
+    cp -a /etc/writable/$f $ROOT/etc/writable
+done
+for f in hosts; do
+    cp -a /etc/$f $ROOT/etc/
+done
+
+
+# don't start services in the chroot on apt-get install
+cat <<EOF > "$ROOT/usr/sbin/policy-rc.d"
+#!/bin/sh
+while true; do
+    case "\$1" in
+      -*) shift ;;
+      makedev) exit 0;;
+      x11-common) exit 0;;
+      *) exit 101;;
+    esac
+done
+EOF
+chmod 755 "$ROOT/usr/sbin/policy-rc.d"
+
+# workaround bug in livecd-rootfs
+chmod 1777 "$ROOT/tmp"