From a9a594f2034c0a077f4d17a3b7f0caf1cf50626e Mon Sep 17 00:00:00 2001
From: Andrew Cady <d@jerkface.net>
Date: Sun, 1 May 2016 01:34:54 -0400
Subject: rename now-ill-named "lvm-create"

---
 src/initrd/btrfs-create.sh | 299 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 299 insertions(+)
 create mode 100644 src/initrd/btrfs-create.sh

(limited to 'src/initrd/btrfs-create.sh')

diff --git a/src/initrd/btrfs-create.sh b/src/initrd/btrfs-create.sh
new file mode 100644
index 0000000..d4a8bdf
--- /dev/null
+++ b/src/initrd/btrfs-create.sh
@@ -0,0 +1,299 @@
+#!/bin/sh
+
+losetup() { /sbin/losetup "$@"; }
+
+luks_secret()
+{
+  local parms=$-; # this junk keeps set -x from being too annoying
+  set +x
+  [ -n "$luks_secret" ] || luks_secret="$(head -c256 /dev/urandom)"
+  printf %s "$luks_secret"
+  case $parms in *x*) set -x; set -x ;; esac
+}
+
+floor4()
+{
+  # Negatives round up, but aren't used.
+  echo $(($1 / 4 * 4))
+}
+
+ceil4()
+{
+  local x="$1"
+  [ $((x % 4)) -eq 0 ] || x=$((x + 4 - x % 4))
+  printf '%d\n' "$x"
+}
+
+. loop-layer.sh
+
+losetup_layers()
+{
+    bootwait samizdat-cdrom
+    local fs fs_rw
+    for fs in /cdrom/rootfs/*.btrfs; do
+        fs_rw=/"${fs##*/}".rw
+        dd if=/dev/zero of="$fs_rw" bs=1M count=10
+        losetup_snapshot "$fs" "$fs_rw" || return
+    done
+}
+
+init_samizdat()
+{
+  local blockdev="$1" imgfile="$2" uuid
+
+  losetup_layers                                   || return
+  modprobe btrfs                                   || return
+  btrfs device scan                                || return
+
+  uuid=$(choose_uuid)                              || return
+  [ "$uuid" ]                                      || return
+
+  mount -t btrfs UUID="$uuid" /root || return
+
+  btrfs device add "$blockdev" /root               || return
+  mount -o rw,remount /root                        || return
+  samizdat_movemounts "$imgfile"                   || return
+
+  initialize_root_filesystem                       || return
+
+  bootdone root-mounted
+}
+
+samizdat_movemounts()
+{
+    local imgfile="$1" mountpoint
+
+    if [ "$imgfile" ]; then
+        mountpoint=$(mountpoint_of "$imgfile") || return
+        mkdir /root/outerfs
+        mount -o move "$mountpoint" /root/outerfs
+    fi
+    mkdir /root/cdrom
+    mount -o move /cdrom /root/cdrom
+    mkdir -p /run/initramfs/samizdat/log
+    cp /var/log/* /run/initramfs/samizdat/log
+    true
+}
+
+mountpoint_of()
+{
+    local f="$1"
+    while ! mountpoint -q "$f"; do
+        f=$(dirname "$f")
+        [ "$f" != '.' ] || return 1
+    done
+    printf '%s\n' "$f"
+}
+
+initialize_root_filesystem()
+{
+    rm -r /root/root
+    btrfs subvolume create /root/root                   || return
+    mv /gpg/gnupghome /root/root/.gnupg                 || return
+
+    rmdir /root/srv
+    btrfs subvolume create /root/srv
+    rm -r /root/var/cache/apt/archives
+    btrfs subvolume create /root/var/cache/apt/archives || return
+
+    rmdir /root/home
+    btrfs subvolume create /root/home                   || return
+
+    [ -x /root/sbin/mdadm ] || cp /sbin/mdadm /root/sbin/
+    # Copy these over unconditionally, because they ought to remain in sync with
+    # the initrd.
+    cp /bin/mdadm-dup.sh /root/sbin/
+    cp /bin/samizdat-eject.sh /root/sbin/
+
+    sed -i -e 's/^root:x:/root::/' /root/etc/passwd
+    cp /patchroot/* /root/root/
+
+    true
+}
+
+# Get the uuid of the filesystem with the most devices,
+# excluding filesystems that don't incorporate loop devices.
+# This is used to choose the latest seed -- which should have
+# the most layers.
+choose_uuid()
+{
+    local seen_loop= seen_uuid= seen_devs=
+    btrfs filesystem show |
+        while read line; do
+            case "$line" in
+                Label*)
+                    seen_uuid=${line##*uuid: }
+                    seen_devs=
+                    seen_loop=
+                    ;;
+                *Total\ devices*)
+                    seen_devs=${line#*Total devices }
+                    seen_devs=${seen_devs%% *}
+                    ;;
+                *path\ /dev/mapper/*)
+                    seen_loop=t;;
+            esac
+            [ "$seen_loop" ] && echo "$seen_devs $seen_uuid"
+        done |
+        uniq | sort -nr | head -n1 | (read _ x; echo $x)
+}
+
+filesystem_incomplete()
+{
+    local n
+    n=$(btrfs filesystem show "$1" | sed -ne 's/.*Total devices \([^ ]*\) .*/\1/p')
+    [ "$n" != 1 ]
+}
+
+open_samizdat()
+{
+  local imgfile="$1" keyfile="$2"
+  open_samizdat_blockdev "$imgfile" "$keyfile" || return
+  local blockdev=/dev/mapper/samizdatcrypt fs
+
+  # For this part, we don't necessarily need the cdrom.
+  # Unfortunately the init_gpg code is still getting the GPG key there.
+  if filesystem_incomplete "$blockdev"; then
+     losetup_layers
+  fi
+  modprobe btrfs || return
+  btrfs device scan || return
+  mount -t btrfs "$blockdev" /root || return
+  samizdat_movemounts "$imgfile"
+  LoSetup -D
+  bootdone root-mounted
+}
+
+init_samizdat_lodev()
+{
+  local imgfile="$1" megs=$(ceil4 "$2") dev
+  truncate -s ${megs}M "$imgfile" || return
+  dev=$(losetup -f) && losetup "$dev" "$imgfile" || return
+  echo "$dev"
+}
+
+open_samizdat_blockdev()
+{
+  local imgfile="$1" keyfile="$2" dev
+  local cryptname=samizdatcrypt
+  dev=$(losetup -f) && losetup "$dev" "$imgfile" || return
+
+  gpg2 --verify "$keyfile" || return
+  # The first --decrypt merely strips the signature.  The option is
+  # poorly named for that case.
+  gpg2 --decrypt "$keyfile" | gpg2 --decrypt | cryptsetup --key-file - luksOpen "$dev" "$cryptname" || return
+
+  [ -b /dev/mapper/"$cryptname" ] || return
+
+}
+
+init_samizdat_blockdev()
+{
+  local imgfile="$1" megs="$2" keyfile="$3" dev
+  local cryptname=samizdatcrypt
+
+  dev=$(init_samizdat_lodev "$imgfile" "$megs") || return
+
+  [ ! -b /dev/mapper/"$cryptname" ] || return
+
+  luks_secret >/dev/null
+  luks_secret | gpg2 --default-recipient-self --encrypt --armor | gpg2 --clearsign --output "$keyfile" || return
+
+  luks_secret | cryptsetup luksFormat "$dev" - || return
+  cryptsetup luksDump "$dev" >&2
+  luks_secret | cryptsetup --key-file - luksOpen "$dev" "$cryptname" || return
+
+  [ -b /dev/mapper/"$cryptname" ] || return
+}
+
+majmin()
+{
+  local dev="$1" major minor
+  eval $(stat -c 'major=%t minor=%T' "$dev") || return
+  [ "$major" -a "$minor" ] || return
+  printf '%d:%d\n' 0x$major 0x$minor
+}
+
+cryptdev_to_dev()
+{
+  local dev="$1" majmin
+  majmin=$(majmin "$dev") || return
+  set -- /sys/dev/block/$majmin/slaves/*
+  [ $# = 1 ] || return
+
+  cryptsetup status "$dev" |while read k v; do if [ "$k" = device: ]; then echo $v; break; fi; done
+}
+
+cryptdev_to_backing_file()
+{
+  local dev="$1" majmin result
+  majmin="$(majmin "$dev")" || return
+  set -- /sys/dev/block/$majmin/slaves/*
+  [ $# = 1 ] || return
+  read result < "$1"/loop/backing_file || return
+  printf '%s\n' "$result"
+}
+
+lodev_to_file()
+{
+  local result majmin dev="$1"
+  majmin="$(majmin "$dev")" || return
+  read result < /sys/dev/block/$majmin/loop/backing_file || return
+  printf '%s' "$result"
+}
+
+mountpoint_to_dev()
+{
+  local wantmp="$1" dev mp rest
+  mountpoint -q "$wantmp" || return
+  while read dev mp rest; do if [ "$mp" = "$wantmp" ]; then echo "$dev"; return; fi; done < /proc/mounts
+  return 1
+}
+
+get_cdrom_sizelimit()
+{
+  # returns bytes
+  local dev="$1" sectors
+  sectors=$(blockdev --getsz "$dev") || return
+  if dd count=2 if="$dev" bs=2048 skip=$((sectors/4 - 2)) of=/dev/null 2>/dev/null; then
+    return
+  else
+    echo $(((sectors-8)*512))
+  fi
+}
+
+init_gpg()
+{
+  bootwait samizdat-cdrom
+  export GNUPGHOME=/gpg/gnupghome
+  mkdir -p "$GNUPGHOME"
+  (umask 077; rsync --exclude '/luks-key*' --ignore-existing -rpP /cdrom/gnupghome/ "$GNUPGHOME")
+
+  if samizdat-password-agent >/var/log/samizdat-password-agent.log 2>&1; then
+    clear
+    true
+  else
+    false
+  fi
+}
+
+start_meter()
+{
+  local startmsg="$*"
+  (exec >&4
+  clear
+  echo -n $startmsg
+  set +x
+  while sleep 2; do
+    echo -n .
+  done) &
+  meterpid=$!
+}
+
+stop_meter()
+{
+  local endmsg="$*"
+  kill $meterpid
+  echo "  $endmsg" >&4
+}
+
-- 
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