From 74ea4d0c1278f2ebc253ff48297159de0c770a2e Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Wed, 13 Jan 2021 12:33:52 +0100
Subject: [PATCH] nixos: add file-systems options

---
 nixos-modules/default.nix       |  1 +
 nixos-modules/file-systems.nix  | 29 +++++++++++++++++++++++++++++
 nixos-modules/genode-core.nix   | 25 ++++++++++++++-----------
 nixos-modules/hardware/ahci.nix |  6 +++---
 tests/ahci.nix                  |  6 +++++-
 tests/lib/build-vms.nix         |  1 +
 6 files changed, 53 insertions(+), 15 deletions(-)
 create mode 100644 nixos-modules/file-systems.nix

diff --git a/nixos-modules/default.nix b/nixos-modules/default.nix
index 54274ba..f6062a5 100644
--- a/nixos-modules/default.nix
+++ b/nixos-modules/default.nix
@@ -4,6 +4,7 @@
 
   x86_64 = {
     imports = [
+      ./file-systems.nix
       ./genode-core.nix
       ./genode-init.nix
       ./gui
diff --git a/nixos-modules/file-systems.nix b/nixos-modules/file-systems.nix
new file mode 100644
index 0000000..9706c83
--- /dev/null
+++ b/nixos-modules/file-systems.nix
@@ -0,0 +1,29 @@
+{ config, lib, pkgs, ... }:
+with lib; {
+
+  options.fileSystems = lib.mkOption {
+    type = types.attrsOf (types.submodule ({ name, config, ... }: {
+      options.block = {
+
+        device = lib.mkOption { type = types.int; };
+
+        driver = lib.mkOption { type = types.enum [ "ahci" ]; };
+
+        partition = lib.mkOption { type = types.ints.positive; };
+
+      };
+    }));
+  };
+
+  config = {
+
+    assertions = [{
+      assertion = config.fileSystems."/".fsType == "ext2";
+      message = "The only supported fsType is EXT2";
+    }];
+
+    hardware.genode.ahci.enable =
+      any (fs: fs.block.driver == "ahci") (attrValues config.fileSystems);
+  };
+
+}
diff --git a/nixos-modules/genode-core.nix b/nixos-modules/genode-core.nix
index faf154f..ea08fa9 100644
--- a/nixos-modules/genode-core.nix
+++ b/nixos-modules/genode-core.nix
@@ -220,7 +220,9 @@ in {
                       , service = "Block"
                       , label = Init.LabelSelector.prefix "store_fs"
                       , attributes = toMap
-                          { partition = "1"
+                          { partition = "${
+                            toString config.fileSystems."/".block.partition
+                          }"
                           , writeable = "yes"
                           , TODO = "select by partition UUID"
                           }
@@ -233,17 +235,18 @@ in {
         { }) // {
           store_fs.configFile = let
 
-            storeVfsConfig = let
-              rumpExt2 = ''
-                VFS.vfs [ VFS.leafAttrs "rump" (toMap { fs = "ext2fs", ram="12M" }) ]
-              '';
-            in {
-              ahci = rumpExt2;
-              tarball = ''
+            storeVfsConfig =
+              if config.genode.boot.storeBackend == "tarball" then ''
                 VFS.vfs [ VFS.leafAttrs "tar" (toMap { name = "${config.system.build.tarball.fileName}.tar" }) ]
-              '';
-              usb = rumpExt2;
-            }.${config.genode.boot.storeBackend};
+              '' else
+                let
+                  rumpExt2 = ''
+                    VFS.vfs [ VFS.leafAttrs "rump" (toMap { fs = "ext2fs", ram="12M" }) ]
+                  '';
+                in {
+                  ahci = rumpExt2;
+                  usb = rumpExt2;
+                }.${config.fileSystems."/".block.driver};
 
             storeResources = let
               rumpExt2 =
diff --git a/nixos-modules/hardware/ahci.nix b/nixos-modules/hardware/ahci.nix
index 1db6177..d34aee4 100644
--- a/nixos-modules/hardware/ahci.nix
+++ b/nixos-modules/hardware/ahci.nix
@@ -10,8 +10,6 @@ with lib;
   config = let cfg = config.hardware.genode.ahci;
   in {
 
-    hardware.genode.ahci.enable = config.genode.boot.storeBackend == "ahci";
-
     hardware.genode.platform.policies = lib.optional cfg.enable
       (builtins.toFile ("ahci.platform-policy.dhall") ''
         let Genode = env:DHALL_GENODE
@@ -52,7 +50,9 @@ with lib;
                   [ Init.Config.Policy::{
                     , service = "Block"
                     , label = Init.LabelSelector.prefix "part_block"
-                    , attributes = toMap { device = "0", writeable = "yes" }
+                    , attributes = toMap { device = "${
+                      toString config.fileSystems."/".block.device
+                    }", writeable = "yes" }
                     }
                   ]
                 }
diff --git a/tests/ahci.nix b/tests/ahci.nix
index eb3e83f..2103025 100644
--- a/tests/ahci.nix
+++ b/tests/ahci.nix
@@ -1,7 +1,11 @@
 {
   name = "ahci";
   machine = { pkgs, ... }: {
-    genode.boot.storeBackend = "ahci";
+    fileSystems."/".block = {
+      driver = "ahci";
+      device = 0;
+      partition = 1;
+    };
     genode.init.children.hello = {
       inputs = [ pkgs.hello pkgs.genodePackages.vfs.lib ];
       configFile = pkgs.writeText "ahci-hello.child.dhall" ''
diff --git a/tests/lib/build-vms.nix b/tests/lib/build-vms.nix
index 51f5db2..5899ee9 100644
--- a/tests/lib/build-vms.nix
+++ b/tests/lib/build-vms.nix
@@ -27,6 +27,7 @@ rec {
       inherit system;
       modules = configurations ++ extraConfigurations;
       baseModules = (import "${modulesPath}/module-list.nix") ++ [
+        ../../nixos-modules/file-systems.nix
         ../../nixos-modules/genode-core.nix
         ../../nixos-modules/genode-init.nix
         ../../nixos-modules/gui