From 4f26e935ee36ddccdf67e8450b57f8e461eabe89 Mon Sep 17 00:00:00 2001
From: Stefan Junker <mail@stefanjunker.de>
Date: Sat, 12 Jan 2019 22:24:30 +0100
Subject: [PATCH] nix/os/devices: add relabel command

After bytewise-copying from a prevoius disk, the partition labels and
logical volume groupnames need to be renamed according to the new disk
id.
---
 Justfile                   |  3 +++
 nix/os/devices/default.nix |  3 ++-
 nix/os/devices/disk.nix    | 47 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/Justfile b/Justfile
index 189ef4c..8651c3d 100755
--- a/Justfile
+++ b/Justfile
@@ -94,6 +94,9 @@ hm-iterate-qtile:
 disk-prepare dir:
 	just -v _device diskPrepare {{dir}} --argstr rebuildarg "dummy"
 
+disk-relabel dir previous:
+	just -v _device diskRelabel {{dir}} --argstr rebuildarg "dummy" --argstr previousDiskId {{previous}}
+
 # Mount the target disk specified by device configuration directory. The 'dir' argument points to a device configuration, e.g. 'nix/os/devices/steveej-live-mmc-SL32G_0x259093f6'
 disk-mount dir:
 	just -v _device diskMount {{dir}} --argstr rebuildarg "dummy"
diff --git a/nix/os/devices/default.nix b/nix/os/devices/default.nix
index b361188..932f730 100644
--- a/nix/os/devices/default.nix
+++ b/nix/os/devices/default.nix
@@ -5,6 +5,7 @@
 , moreargs ? ""
 , diskId ? (import ((builtins.getEnv "PWD")+"/${dir}/hw.nix") {}).hardware.encryptedDisk.diskId
 , gitRoot ? "$(git rev-parse --show-toplevel)"
+, previousDiskId ? ""
 }:
 
 let
@@ -35,5 +36,5 @@ let
 in {
   recipes = {
     inherit rebuild;
-  } // (import ./disk.nix { inherit pkgs ownLib dir rebuildarg moreargs diskId gitRoot; });
+  } // (import ./disk.nix { inherit pkgs ownLib dir rebuildarg moreargs diskId gitRoot previousDiskId; });
 }
diff --git a/nix/os/devices/disk.nix b/nix/os/devices/disk.nix
index 4490311..6b012d8 100644
--- a/nix/os/devices/disk.nix
+++ b/nix/os/devices/disk.nix
@@ -5,6 +5,7 @@
 , moreargs
 , diskId
 , gitRoot
+, previousDiskId ? ""
 }:
 
 let
@@ -117,4 +118,50 @@ in rec {
 
     ${diskUmount}
   '';
+
+  diskRelabel = pkgs.writeScript "script" ''
+    #!/usr/bin/env bash
+    set -xe
+
+    read -p "Continue to relabel ${ownLib.disk.bootGrubDevice diskId} (YES/n)?" choice
+    case "$choice" in
+      YES ) echo "Continuing in 3 seconds..."; sleep 3;;
+      n|N ) echo "Exiting..."; exit 0;;
+      * ) echo "Exiting..."; exit 1;;
+    esac
+
+    sync
+    {
+    sudo fdisk ${ownLib.disk.bootGrubDevice diskId} <<EOF
+    x
+    n
+    2
+    2-${diskId}
+    n
+    3
+    3-${diskId}
+    r
+    i
+    2
+    i
+    3
+    w
+    EOF
+    } || {
+      sync
+      sudo partprobe  ${ownLib.disk.bootGrubDevice diskId}
+    }
+
+
+    if test "${previousDiskId}"; then
+      sudo cryptsetup luksOpen ${ownLib.disk.bootLuksDevice diskId} ${ownLib.disk.luksName diskId}
+      sync
+      sleep 1
+      if sudo vgs ${previousDiskId}; then
+        sudo vgrename ${previousDiskId} ${diskId}
+        sudo vgscan
+      fi
+    fi
+    sudo cryptsetup close ${ownLib.disk.luksName diskId}
+  '';
 }