virtiofsd: fix nix chroot store support

flake.nix

@@ -96,6 +96,7 @@
             ./nixosModules/flake-module.nix
             ./pkgs/flake-module.nix
             ./templates/flake-module.nix
+            ./pkgs/clan-cli/clan_cli/tests/flake-module.nix
           ]
         ++ [
           (if pathExists ./flakeModules/clan.nix then import ./flakeModules/clan.nix inputs.self else { })

pkgs/clan-cli/clan_cli/vms/virtiofsd.py

@@ -1,4 +1,5 @@
 import contextlib
+import logging
 import shutil
 import subprocess
 import time
@@ -6,7 +7,9 @@ from collections.abc import Iterator
 from pathlib import Path
 
 from clan_lib.errors import ClanError
-from clan_lib.nix import nix_shell
+from clan_lib.nix import nix_shell, nix_test_store
+
+log = logging.getLogger(__name__)
 
 
 @contextlib.contextmanager
@@ -14,6 +17,9 @@ def start_virtiofsd(socket_path: Path) -> Iterator[None]:
     sandbox = "namespace"
     if shutil.which("newuidmap") is None:
         sandbox = "none"
+    store_root = nix_test_store() or Path("/")
+    store = store_root / "nix" / "store"
+
     virtiofsd = nix_shell(
         ["virtiofsd"],
         [
@@ -25,9 +31,10 @@ def start_virtiofsd(socket_path: Path) -> Iterator[None]:
             "--sandbox",
             sandbox,
             "--shared-dir",
-            "/nix/store",
+            str(store),
         ],
     )
+    log.debug("$ {}".format(" ".join(virtiofsd)))
     with subprocess.Popen(virtiofsd) as proc:
         try:
             while not socket_path.exists():

pkgs/clan-cli/flake-module.nix

@@ -25,6 +25,7 @@
             "clanServices"
             "pkgs/zerotierone"
             "pkgs/minifakeroot"
+            "pkgs/clan-cli/clan_cli/tests/flake-module.nix"
           ];
         };
       };