mkimage-profiles/features.in/syslinux/scripts.d/20-propagator-rescue-hash-syslinux

#!/bin/sh
# postprocess isolinux configuration
# to add rescue image hash, if any
# (for propagator in forensic mode)

# validate just in case (see also stage1 Makefile)
if [ -z "$(find $WORKDIR/syslinux/*.cfg)" ]; then
	echo "Warning: syslinux/*.cfg not found"
	exit 0
fi

cd "$WORKDIR"

grep -qs "@rescue_hash@" syslinux/*.cfg || exit 0

find -maxdepth 1 -type f -name rescue \
| while read image; do
	rescue_hash="$(sha256sum -b "$image" | cut -f1 -d' ')"
	sed -i "s,@rescue_hash@,$rescue_hash," syslinux/*.cfg
done