fix paths (in progress)

1 files changed, 217 insertions, 0 deletions

diff --git a/src/initrd/mdadm-dup.sh b/src/initrd/mdadm-dup.sh
new file mode 100644
index 0000000..70163a5
--- /dev/null
+++ b/src/initrd/mdadm-dup.sh
@@ -0,0 +1,217 @@
+LoSetup()
+{
+    local losetup_binary="$(which LoSetup)"
+    if [ "$losetup_binary" ]; then
+        "$losetup_binary" "$@"
+    else
+        losetup "$@"
+    fi
+}
+
+dm_snapshot()
+{
+    # TODO: eliminate duplication; this function exists elsewhere in a less generalized form
+    local ro_file rw_file cutoff_size
+    ro_file=$1
+    rw_file=$2
+    cutoff_size=$3
+
+    local ro_dev rw_dev size new_dev_name persist chunksize
+
+    if [ -b "$ro_file" ];
+    then ro_dev=$ro_file
+    else ro_dev=$(LoSetup -r -f --show "$ro_file") || return
+    fi
+
+    if [ -b "$rw_file" ];
+    then rw_dev=$rw_file
+    else rw_dev=$(LoSetup -f --show "$rw_file") || return
+    fi
+
+    if [ "$cutoff_size" -a "$cutoff_size" -gt 0 ]; then
+        size=$cutoff_size
+    else
+        size=$(blockdev --getsz "$ro_dev") || return
+    fi
+
+    new_dev_name=${ro_dev##*/}
+    persist=p
+    chunksize=16
+    dmsetup create "$new_dev_name" --table "0 $size snapshot $ro_dev $rw_dev $persist $chunksize" || return
+    wait_for_dm_device /dev/mapper/"$new_dev_name"
+    echo /dev/mapper/"$new_dev_name"
+}
+
+dm_snapshot_teardown()
+{
+    local dev="$1"
+    case "$dev" in
+        /dev/dm-*)
+            dmsetup table "$dev" | (
+                read _ _ snapshot ro_dev rw_dev _ crypt_dev _
+                case "$snapshot" in
+                    snapshot)
+                        dmsetup remove "$dev"           || exit 1
+                        # errors ignored because the loop dev can be configured to be
+                        # automatically removed upon disuse
+                        losetup -d /dev/block/"$rw_dev" || true
+                        eject /dev/block/"$ro_dev"      || true
+                        ;;
+                    crypt)
+                        cryptsetup remove "$dev" || exit 1
+                        losetup -d /dev/block/"$crypt_dev" || true
+                        ;;
+                esac
+            ) || return
+            ;;
+        *) return 1 ;;
+    esac
+}
+
+wait_for_dm_device()
+{
+    # TODO: improve
+    while ! [ -e "$1" ]; do
+        sleep 1
+    done
+}
+
+dup_mount_cdrom()
+{
+    local cdrom_dev="$1" mountpoint="$2"
+
+    local sectors md_dev=/dev/md55 cdrom_rw_file=/"${cdrom_dev##*/}".rw
+
+    sectors=$(get_cdrom_sizelimit "$cdrom_dev") || return
+
+    # TODO: do we even need this backing file? We do need to trick mdadm into
+    # thinking that this is a RW device, but previously we got away with just
+    # creating a loopback device.
+    dd if=/dev/zero of="$cdrom_rw_file" bs=1K count=32 || return
+    cdrom_rw_dev=$(dm_snapshot "$cdrom_dev" "$cdrom_rw_file" "$sectors") || return
+    mdadm_dup "$cdrom_rw_dev" "$md_dev" "$sectors" || return
+    mount -t iso9660 -r $md_dev "$mountpoint"
+}
+
+get_cdrom_sizelimit()
+{
+    # returns 512-byte sectors
+    local dev="$1" sectors
+    sectors=$(blockdev --getsz "$dev") || return
+
+    # Check if we can read the last 8 sectors. With a TAO CDROM, we can't --
+    # these sectors are faux, and not part of the ISO fs. If mdadm is allowed to
+    # read them, it will mark the device failed.
+    if dd count=2 if="$dev" bs=2048 skip=$((sectors/4 - 2)) of=/dev/null 2>/dev/null; then
+        echo $sectors
+    else
+        echo $((sectors - 8))
+    fi
+}
+
+mdadm_dup()
+{
+    local input_dev="$1" md_name="$2" sectors="$3"
+
+    mdadm --build "$md_name" "${sectors:+--size=$((sectors / 2))}" \
+          --level=1 --raid-devices=1 --force --write-mostly "$input_dev" || return
+}
+
+mdadm_subdevices()
+{
+    local md_dev="$1"
+    mdadm -D "$md_dev" -Y | sed -ne 's/^MD_DEVICE_.*_DEV=//p'
+}
+
+cryptsetup_temp()
+{
+    local sectors="$1" cryptname="$2" temp_file="$3" parms=$- secret
+    set +x
+    # Add 4096 sectors for LUKS header
+    truncate -s $(((sectors + 4096) * 512)) "$temp_file" || return
+    cleartext_dev=$(LoSetup -f --show "$temp_file")      || return
+    secret="$(head -c256 /dev/urandom)"                  || return
+    printf %s "$secret" |
+        cryptsetup luksFormat "$cleartext_dev" - || return
+    printf %s "$secret" |
+        cryptsetup --key-file - luksOpen "$cleartext_dev" "$cryptname" || return
+    unset secret
+    set "$parms"
+
+    wait_for_dm_device /dev/mapper/"$cryptname"
+    rm "$temp_file"
+    echo /dev/mapper/"$cryptname"
+}
+
+mdadm_copy_eject_crypt()
+{
+    local md_dev="$1" temp_file="$2"
+
+    [ -b "$md_dev" ]                                  || return
+
+    local output_dev sectors
+
+    old_subdev=$(mdadm_subdevices "$md_dev"|head -n1) || return
+    [ -b "$old_subdev" ]                              || return
+    # TODO: truncate to the ISO fs size if the device is larger
+    sectors=$(blockdev --getsz "$md_dev")             || return
+
+    output_dev=$(cryptsetup_temp "$sectors" samizdatiso "$temp_file") || return
+
+    mdadm "$md_dev" --add "$output_dev"               || return
+    mdadm "$md_dev" --grow -n2                        || return
+
+    mdadm_wait_remove "$md_dev" "$old_subdev"         || return
+
+    mdadm "$md_dev" --grow -n1 --force                || return
+    dm_snapshot_teardown "$old_subdev"
+}
+
+mdadm_copy_eject()
+{
+    local md_dev="$1" output_file="$2"
+
+    [ -b "$md_dev" ]                                  || return
+    [ ! -e "$output_file" ]                           || return
+
+    local output_dev sectors
+
+    old_subdev=$(mdadm_subdevices "$md_dev"|head -n1) || return
+    [ -b "$old_subdev" ]                              || return
+    sectors=$(blockdev --getsz "$md_dev")             || return
+
+    truncate -s $((sectors * 512)) "$output_file"     || return
+    output_dev=$(LoSetup -f --show "$output_file")    || return
+
+    mdadm "$md_dev" --add "$output_dev"               || return
+    mdadm "$md_dev" --grow -n2                        || return
+
+    mdadm_wait_remove "$md_dev" "$old_subdev"         || return
+
+    mdadm "$md_dev" --grow -n1 --force                || return
+    dm_snapshot_teardown "$old_subdev"
+}
+
+mdadm_wait_remove()
+{
+    # We should perhaps use mdadm --monitor's RebuildFinished event.
+
+    local dev="$1" disk="$2" tries
+    if ! mdadm --wait "$dev"; then
+        tries=1000
+        while ! mdadm --detail --test "$dev"; do
+            [ $tries -gt 0 ] || return 1
+            sleep 1
+            tries=$((tries-1))
+        done
+    fi
+
+    mdadm "$dev" --fail "$disk" || return 1
+    tries=100
+    while ! mdadm "$dev" --remove "$disk"; do
+        [ $tries -gt 0 ] || return 1
+        sleep 1
+        tries=$((tries-1))
+    done
+    return 0
+}