Script to store certificates into separate partition

cert-backup/README

+cert-backup
+===========
+
+A script that stores the given certificate onto a backup partition for the case
+of full restart (eg. data wipe).
+
+Call with list of files to store or remove. Each file to remove must be
+preceded by -r.
+
+For example, to add files /etc/a and /etc/b and remove /etc/c and /etc/d, you'd
+call it as:
+
+  ./cert-backup /etc/a /etc/b -r /etc/c -r /etc/d

cert-backup/cert-backup

+#!/bin/sh
+
+set -ex
+
+PARTITION=/dev/mtdblock4
+WORKDIR=/tmp/certstore
+
+mkdir -p "$WORKDIR"
+test -z "$(ls -A "$WORKDIR")"
+mount -t jffs2 "$PARTITION" "$WORKDIR"
+while [ "$1" ] ; do
+	if [ "$1" = '-r' ] ; then
+		# It should be removed, if it exists
+		shift
+		rm -f "$WORKDIR"/"$1"
+	elif cmp -s "$1" "$WORKDIR"/"$1" ; then
+		echo "$1" already stored, skipping
+	else
+		# It differs (or the backup doesn't exist) -> replace
+		mkdir -p "$WORKDIR"/"$(dirname "$1")"
+		cp -a "$1" "$WORKDIR"/"$1"
+	fi
+	shift
+done
+umount "$WORKDIR"
+rm -r "$WORKDIR"