feat: migrate from modules to features

features/vm-9p-automount.nix

@@ -0,0 +1,72 @@
+{
+  nixos =
+    {
+      pkgs,
+      lib,
+      config,
+      ...
+    }:
+    let
+      inherit (config.vm-9p-automount) user;
+      inherit (config.users.users.${user}) home group;
+    in
+    {
+      options = {
+        vm-9p-automount = {
+          user = lib.mkOption {
+            type = lib.types.str;
+          };
+
+          prefix = lib.mkOption {
+            type = lib.types.str;
+            default = "m_";
+          };
+
+          basePath = lib.mkOption {
+            type = lib.types.str;
+            default = "${home}/mnt";
+          };
+        };
+      };
+
+      config = {
+        systemd.services.vm-9p-automount = {
+          description = "Auto-discover and mount 9p shares";
+          after = [
+            "local-fs.target"
+            "nss-user-lookup.target"
+            "systemd-modules-load.service"
+          ];
+          wants = [ "systemd-modules-load.service" ];
+          wantedBy = [ "multi-user.target" ];
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+            ExecStart = pkgs.writeShellScript "vm-9p-automount" ''
+              BASE="${config.vm-9p-automount.basePath}"
+              PREFIX="${config.vm-9p-automount.prefix}"
+              mkdir -p "$BASE"
+              chown ${user}:${group} "$BASE"
+
+              for tagfile in $(find /sys/devices -name mount_tag 2>/dev/null); do
+                [ -f "$tagfile" ] || continue
+                tag=$(tr -d '\0' < "$tagfile")
+
+                case "$tag" in
+                  "$PREFIX"*) ;;
+                  *) continue ;;
+                esac
+
+                name="''${tag#"$PREFIX"}"
+                target="$BASE/$name"
+
+                mkdir -p "$target"
+                ${pkgs.util-linux}/bin/mount -t 9p "$tag" "$target" \
+                  -o trans=virtio,version=9p2000.L || continue
+              done
+            '';
+          };
+        };
+      };
+    };
+}