#!/bin/sh

PREREQ="cryptroot-prepare"

#
# Standard initramfs preamble
#
prereqs() {
    # Make sure that cryptroot is run last in local-top
    local req script="${0##*/}" dir
    dir="$DESTDIR/scripts/${CRYPTROOT_STAGE-local-top}"
    for req in "$dir"/*; do
        test -x "$req" || continue
        req="${req##*/}"
        if [ "$req" != "$script" ]; then
            printf '%s\n' "$req"
        fi
    done
}

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

. /scripts/functions

[ -f /lib/cryptsetup/functions ] || return 0
. /lib/cryptsetup/functions


# wait_for_source()
#   Wait for encrypted $CRYPTTAB_SOURCE . Set $CRYPTTAB_SOURCE
#   to its normalized device name when it shows up;
#   return 1 if timeout.
wait_for_source() {
    wait_for_udev 10

    if crypttab_resolve_source; then
        # the device is here already, no need to loop
        return 0
    fi

    # If the source device hasn't shown up yet, give it a little while
    # to allow for asynchronous device discovery (e.g. USB).
    #
    # We also need to take into account RAID or other devices that may
    # only be available on local-block stage. So, wait 5 seconds upfront,
    # in local-top; if that fails, end execution relying on local-block
    # invocations. Allow $ROOTDELAY/4 invocations with 1s sleep times (with
    # a minimum of 20 invocations), and if after that we still fail, then it's
    # really time to give-up. Variable $initrd_cnt tracks the re-invocations.
    #
    # Part of the lines below has been taken from initramfs-tools
    # scripts/local's local_device_setup(), as suggested per
    # https://launchpad.net/bugs/164044 .

    local slumber=5
    if [ "${CRYPTROOT_STAGE-}" = "local-block" ]; then
         slumber=1
    fi

    cryptsetup_message "Waiting for encrypted source device $CRYPTTAB_SOURCE..."

    while [ $slumber -gt 0 ]; do
        sleep 1

        if crypttab_resolve_source; then
            wait_for_udev 10
            return 0
        fi

        slumber=$(( $slumber - 1 ))
    done
    return 1
}

# setup_mapping()
#   Set up a crypttab(5) mapping defined by $CRYPTTAB_NAME,
#   $CRYPTTAB_SOURCE, $CRYPTTAB_KEY, $CRYPTTAB_OPTIONS.
setup_mapping() {
    local dev initrd_cnt

    # We control here the number of re-invocations of this script from
    # local-block - the heuristic is $ROOTDELAY/4, with a minimum of 20.

    if [ -f "$CRYPTROOT_COUNT_FILE" ]; then
        initrd_cnt="$(cat <"$CRYPTROOT_COUNT_FILE")"
    else
        initrd_cnt="${ROOTDELAY:-180}"
        initrd_cnt=$(( initrd_cnt/4 ))
        if [ $initrd_cnt -lt 20 ]; then
            initrd_cnt=20
        fi
        echo "$initrd_cnt" >"$CRYPTROOT_COUNT_FILE"
    fi

    # The same target can be specified multiple times
    # e.g. root and resume lvs-on-lvm-on-crypto
    if dm_blkdevname "$CRYPTTAB_NAME" >/dev/null; then
        return 0
    fi

    crypttab_parse_options --export --missing-path=fail || return 1

    if ! wait_for_source; then
        if [ $initrd_cnt -eq 0 ]; then
            # we've given up
            if [ -n "$panic" ]; then
                panic "ALERT! encrypted source device $CRYPTTAB_SOURCE does not exist, can't unlock $CRYPTTAB_NAME."
            else
                # let the user fix matters if they can
                echo "	ALERT! encrypted source device $CRYPTTAB_SOURCE does not exist, can't unlock $CRYPTTAB_NAME."
                echo "	Check cryptopts=source= bootarg: cat /proc/cmdline"
                echo "	or missing modules, devices: cat /proc/modules; ls /dev"
                panic "Dropping to a shell."
            fi
            return 1 # can't continue because environment is lost
        else
            initrd_cnt=$(( initrd_cnt - 1 ))
            echo "$initrd_cnt" >"$CRYPTROOT_COUNT_FILE"
            return 0 # allow some attempts on local-block stage
        fi
    fi

    # our `cryptroot-unlock` script searches for cryptsetup processes
    # with a given CRYPTTAB_NAME it their environment
    export CRYPTTAB_NAME

    if [ -z "${CRYPTTAB_OPTION_keyscript+x}" ]; then
        # no keyscript: interactive unlocking, or key file

        if [ "${CRYPTTAB_KEY#/FIXME-initramfs-rootmnt/}" != "$CRYPTTAB_KEY" ]; then
            # skip the mapping for now if the root FS is not mounted yet
            sed -rn 's/^\s*[^#[:blank:]]\S*\s+(\S+)\s.*/\1/p' /proc/mounts | grep -Fxq -- "$rootmnt" || return 1
            # substitute the "/FIXME-initramfs-rootmnt/" prefix by the real root FS mountpoint otherwise
            CRYPTTAB_KEY="$rootmnt/${CRYPTTAB_KEY#/FIXME-initramfs-rootmnt/}"
        fi

        if [ "$CRYPTTAB_KEY" != "none" ]; then
            if [ ! -e "$CRYPTTAB_KEY" ]; then
                cryptsetup_message "ERROR: Skipping target $CRYPTTAB_NAME: non-existing key file $CRYPTTAB_KEY"
                return 1
            fi
            # try only once if we have a key file
            CRYPTTAB_OPTION_tries=1
        fi
    fi

    local count=0 maxtries="${CRYPTTAB_OPTION_tries:-3}" fstype vg rv
    while [ $maxtries -le 0 ] || [ $count -lt $maxtries ]; do
        if [ -z "${CRYPTTAB_OPTION_keyscript+x}" ] && [ "$CRYPTTAB_KEY" != "none" ]; then
            # unlock via keyfile
            unlock_mapping "$CRYPTTAB_KEY"
        else
            # unlock interactively or via keyscript
            run_keyscript "$count" | unlock_mapping
        fi
        rv=$?
        count=$(( $count + 1 ))

        if [ $rv -ne 0 ]; then
            cryptsetup_message "ERROR: $CRYPTTAB_NAME: cryptsetup failed, bad password or options?"
            sleep 1
            continue
        elif ! dev="$(dm_blkdevname "$CRYPTTAB_NAME")"; then
            cryptsetup_message "ERROR: $CRYPTTAB_NAME: unknown error setting up device mapping"
            return 1
        fi

        if ! fstype="$(get_fstype "$dev")" || [ "$fstype" = "unknown" ]; then
            if [ "$CRYPTTAB_TYPE" != "luks" ]; then
                # bad password for plain dm-crypt device?  or mkfs not run yet?
                cryptsetup_message "ERROR: $CRYPTTAB_NAME: unknown fstype, bad password or options?"
                wait_for_udev 10
                /sbin/cryptsetup remove -- "$CRYPTTAB_NAME"
                sleep 1
                continue
            fi
        fi

        cryptsetup_message "$CRYPTTAB_NAME: set up successfully"
        wait_for_udev 10
        return 0
    done

    cryptsetup_message "ERROR: $CRYPTTAB_NAME: maximum number of tries exceeded"
    exit 1
}


#######################################################################
# Begin real processing

mkdir -p /cryptroot # might not exist yet if the main system has no crypttab(5)

# Do we have any kernel boot arguments?
if ! grep -qE '^(.*\s)?cryptopts=' /proc/cmdline; then
    # ensure $TABFILE exists and has a mtime greater than the boot time
    # (existing $TABFILE is preserved)
    touch -- "$TABFILE"
else
    # let the read builtin unescape the '\' as GRUB substitutes '\' by '\\' in the cmdline
    tr ' ' '\n' </proc/cmdline | sed -n 's/^cryptopts=//p' | while IFS= read cryptopts; do
        # skip empty values (which can be used to disable the initramfs
        # scripts for a particular boot, cf. #873840)
        [ -n "$cryptopts" ] || continue
        unset -v target source key options

        IFS=","
        for x in $cryptopts; do
            case "$x" in
                target=*) target="${x#target=}";;
                source=*) source="${x#source=}";;
                key=*) key="${x#key=}";;
                *) options="${options+$options,}$x";;
            esac
        done

        if [ -z "${source:+x}" ]; then
            cryptsetup_message "ERROR: Missing source= value in kernel parameter cryptopts=$cryptopts"
        else
            # preserve mangling
            printf '%s %s %s %s\n' "${target:-cryptroot}" "$source" "${key:-none}" "${options-}"
        fi
    done >"$TABFILE"
fi

# Do we have any settings from the $TABFILE?
if [ -s "$TABFILE" ]; then
    # Create locking directory before invoking cryptsetup(8) to avoid warnings
    mkdir -pm0700 /run/cryptsetup
    modprobe -q dm_crypt

    crypttab_foreach_entry setup_mapping
fi

exit 0