#!/bin/sh

PREREQ=""

prereqs() {
    echo "$PREREQ"
}

case "$1" in
    prereqs)
        prereqs
        exit 0
    ;;
esac

. /usr/share/initramfs-tools/hook-functions

dropbear_warn() {
    echo "dropbear: WARNING:" "$@" >&2
}

copy_exec /usr/sbin/dropbear /sbin
for so in $(ldconfig -p | sed -nr 's/^\s*libnss_files\.so\.[0-9]+\s.*=>\s*//p'); do
    copy_exec "$so"
done

home="$(mktemp --directory -- "$DESTDIR/root-XXXXXXXXXX")" # avoid collisions with $rootmnt
chmod 0700 -- "$home"
for x in passwd group; do echo "$x: files"; done >"$DESTDIR/etc/nsswitch.conf"
echo "root:*:0:0::${home#"$DESTDIR"}:/bin/sh" >"$DESTDIR/etc/passwd"
echo "root:!:0:" >"$DESTDIR/etc/group"

# Copy config and host keys
mkdir -p -- "$DESTDIR/etc/dropbear"
if [ -e /etc/dropbear-initramfs/config ]; then
    cp -pt "$DESTDIR/etc/dropbear" "/etc/dropbear-initramfs/config"
fi

copied_hostkey="n"
for keytype in dss rsa ecdsa ed25519; do
    hostkey="/etc/dropbear-initramfs/dropbear_${keytype}_host_key"
    if [ -f "$hostkey" ]; then
        cp -pt "$DESTDIR/etc/dropbear" "$hostkey"
        copied_hostkey="y"
    fi
done
if [ "$copied_hostkey" = "n" ]; then
    dropbear_warn "Missing host keys, SSH login to initramfs won't work!"
fi

# Copy authorized_keys
mkdir -m0700 -- "$home/.ssh"
if [ -e /etc/dropbear-initramfs/authorized_keys ]; then
    cat /etc/dropbear-initramfs/authorized_keys
else
    for keytype in dsa rsa ecdsa ed25519; do
        pubkey="/etc/dropbear-initramfs/id_${keytype}.pub"
        if [ -e "$pubkey" ]; then
            cat "$pubkey"
        fi
    done
fi >"$home/.ssh/authorized_keys"

if ! grep -qE '^([^#]+)?(ssh-(dss|rsa|ed25519)|ecdsa-sha2-nistp(256|384|521)) ' <"$home/.ssh/authorized_keys"; then
    dropbear_warn "Invalid authorized_keys file, SSH login to initramfs won't work!"
fi
