shell bypass 403
#!/bin/sh
if [ "${root%%:*}" = "block" ]; then
{
printf 'KERNEL=="%s", SYMLINK+="root"\n' \
${root#block:/dev/}
printf 'SYMLINK=="%s", SYMLINK+="root"\n' \
${root#block:/dev/}
} >> /etc/udev/rules.d/99-root.rules
printf '[ -e "%s" ] && { ln -s "%s" /dev/root 2>/dev/null; rm "$job"; }\n' \
"${root#block:}" "${root#block:}" > $hookdir/initqueue/settled/blocksymlink.sh
wait_for_dev "${root#block:}"
fi