From a9d847e2c0a76ff01cb9eb026237cc227e2d8618 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 6 Nov 2023 21:52:31 +0000
Subject: [PATCH] add ext4 as rootfsType

---
 modules/base.nix             |  7 +++++-
 modules/ext4fs.nix           | 45 ++++++++++++++++++++++++++++++++++++
 tests/ci.nix                 |  3 ++-
 tests/ext4/configuration.nix | 19 +++++++++++++++
 tests/ext4/script.expect     | 11 +++++++++
 tests/ext4/test.nix          | 19 +++++++++++++++
 6 files changed, 102 insertions(+), 2 deletions(-)
 create mode 100644 modules/ext4fs.nix
 create mode 100644 tests/ext4/configuration.nix
 create mode 100644 tests/ext4/script.expect
 create mode 100644 tests/ext4/test.nix

diff --git a/modules/base.nix b/modules/base.nix
index 67d6ed7..75bb3b3 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -39,7 +39,12 @@ in {
     };
     rootfsType =  mkOption {
       default = "squashfs";
-      type = types.enum ["squashfs" "jffs2" "ubifs"];
+      type = types.enum [
+        "ext4"
+        "jffs2"
+        "squashfs"
+        "ubifs"
+      ];
     };
     boot = {
       commandLine = mkOption {
diff --git a/modules/ext4fs.nix b/modules/ext4fs.nix
new file mode 100644
index 0000000..6a8c7c8
--- /dev/null
+++ b/modules/ext4fs.nix
@@ -0,0 +1,45 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkIf mkOption types;
+in
+{
+  imports = [
+    ./initramfs.nix
+  ];
+  config = mkIf (config.rootfsType == "ext4") {
+    kernel.config = {
+      EXT4_FS = "y";
+      EXT4_USE_FOR_EXT2 = "y";
+      FS_ENCRYPTION = "y";
+    };
+    boot.initramfs.enable = true;
+    system.outputs = rec {
+      systemConfiguration =
+        pkgs.systemconfig config.filesystem.contents;
+      rootfs =
+        let
+          inherit (pkgs.pkgsBuildBuild) runCommand e2fsprogs;
+        in runCommand "mkfs.ext4" {
+          depsBuildBuild = [ e2fsprogs ];
+        } ''
+          mkdir -p $TMPDIR/empty/nix/store/ $TMPDIR/empty/secrets
+          cp ${systemConfiguration}/bin/activate $TMPDIR/empty/activate
+          ln -s ${pkgs.s6-init-bin}/bin/init $TMPDIR/empty/init
+          mkdir -p $TMPDIR/empty/nix/store
+          for path in $(cat ${systemConfiguration}/etc/nix-store-paths) ; do
+            (cd $TMPDIR/empty && cp -a $path .$path)
+          done
+          size=$(du -s --apparent-size --block-size 1024 $TMPDIR/empty |cut -f1)
+          # add 25% for filesystem overhead
+          size=$(( 5 * $size / 4))
+          dd if=/dev/zero of=$out bs=1024 count=$size
+          mke2fs -t ext4 -j -d $TMPDIR/empty $out
+        '';
+    };
+  };
+}
diff --git a/tests/ci.nix b/tests/ci.nix
index 315112c..c84ae07 100644
--- a/tests/ci.nix
+++ b/tests/ci.nix
@@ -3,7 +3,8 @@
   pseudofiles = import ./pseudofiles/test.nix;
   wlan = import ./wlan/test.nix;
   pppoe = import ./pppoe/test.nix;
-  jffs2 =  import ./jffs2/test.nix;
+  jffs2 = import ./jffs2/test.nix;
+  ext4 = import ./ext4/test.nix;
   min-copy-closure =  import ./min-copy-closure/test.nix;
   fennel = import ./fennel/test.nix;
 }
diff --git a/tests/ext4/configuration.nix b/tests/ext4/configuration.nix
new file mode 100644
index 0000000..258e2b3
--- /dev/null
+++ b/tests/ext4/configuration.nix
@@ -0,0 +1,19 @@
+{ config, pkgs, lib, ... } :
+let
+  inherit (pkgs.pseudofile) dir symlink;
+in {
+  imports = [
+    ../../vanilla-configuration.nix
+    ../../modules/squashfs.nix
+    ../../modules/ext4fs.nix
+  ];
+  config.rootfsType = "ext4";
+  config.filesystem = dir {
+    hello = {
+      type = "f";
+      uid = 7;
+      gid = 24;
+      file = "hello world";
+    };
+  };
+}
diff --git a/tests/ext4/script.expect b/tests/ext4/script.expect
new file mode 100644
index 0000000..4d78c5e
--- /dev/null
+++ b/tests/ext4/script.expect
@@ -0,0 +1,11 @@
+set timeout 10
+
+spawn socat unix-connect:vm/console -
+send "\r\n"
+expect "login:" {  send "root\r\n" }
+expect "#"
+send "echo HELLO WORLD > /hello\r\n"
+expect "#"
+send "cat /hello\r\n"
+expect 'HELLO WORLD'
+close
\ No newline at end of file
diff --git a/tests/ext4/test.nix b/tests/ext4/test.nix
new file mode 100644
index 0000000..f972583
--- /dev/null
+++ b/tests/ext4/test.nix
@@ -0,0 +1,19 @@
+{
+  liminix
+, nixpkgs
+}:
+let img = (import liminix {
+      device = import "${liminix}/devices/qemu/";
+      liminix-config = ./configuration.nix;
+    }).outputs.vmroot;
+    pkgs = import <nixpkgs> { overlays = [(import ../../overlay.nix)]; };
+in pkgs.runCommand "check" {
+  nativeBuildInputs = with pkgs; [
+    expect
+    socat
+  ] ;
+} ''
+mkdir vm
+${img}/run.sh --background ./vm
+expect ${./script.expect} >$out
+''