host/initramfs: panic if roothash is missing

We're not going to be able to boot if we don't know what roothash
we're looking for, so abort the boot at that point rather than hanging
forever.

This should never happen on an actual system, but it makes things
clearer in testing if something has gone wrong with the kernel command
line.

Signed-off-by: Alyssa Ross <hi@alyssa.is>

3 files changed, 39 insertions, 1 deletions

diff --git a/host/initramfs/etc/getuuids b/host/initramfs/etc/getuuids
index 90fda10..62f8935 100755
--- a/host/initramfs/etc/getuuids
+++ b/host/initramfs/etc/getuuids
@@ -1,6 +1,6 @@
 #!/bin/awk -f
 # SPDX-License-Identifier: EUPL-1.2+
-# SPDX-FileCopyrightText: 2021 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2021, 2023 Alyssa Ross <hi@alyssa.is>
 
 function to_uuid(hex) {
     return substr(hex, 1, 8) "-" substr(hex, 9, 4) "-" substr(hex, 13, 4) "-" \
@@ -8,6 +8,11 @@ function to_uuid(hex) {
 }
 
 BEGIN {
+    if (length(ENVIRON["roothash"]) != 64) {
+	system("echo 'roothash invalid or missing' >&2")
+	exit 1
+    }
+
     print to_uuid(substr(ENVIRON["roothash"], 1, 32))
     print to_uuid(substr(ENVIRON["roothash"], 33, 32))
 }
diff --git a/release/checks/default.nix b/release/checks/default.nix
index bf26b9a..bae9159 100644
--- a/release/checks/default.nix
+++ b/release/checks/default.nix
@@ -10,6 +10,8 @@ import ../../lib/eval-config.nix ({ ... } @ args:
 
   pkg-tests = import ./pkg-tests.nix args;
 
+  no-roothash = import ./no-roothash.nix args;
+
   reuse = import ./reuse.nix args;
 
   rustfmt = import ./rustfmt.nix args;
diff --git a/release/checks/no-roothash.nix b/release/checks/no-roothash.nix
new file mode 100644
index 0000000..4c5c19c
--- /dev/null
+++ b/release/checks/no-roothash.nix
@@ -0,0 +1,31 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2023 Alyssa Ross <hi@alyssa.is>
+
+import ../../lib/eval-config.nix ({ config, ... }:
+
+let
+  rootfs = import ../../host/rootfs { inherit config; };
+  initramfs = import ../../host/initramfs { inherit config rootfs; };
+in
+
+config.pkgs.nixosTest ({ stdenv, ... }: {
+  name = "spectrum-test-initramfs-no-roothash";
+  nodes = {};
+
+  testScript = ''
+    import shlex
+
+    flags = " ".join(map(shlex.quote, [
+      "qemu-kvm",
+      "-m", "512",
+      "-kernel", "${rootfs.kernel}/${stdenv.hostPlatform.linux-kernel.target}",
+      "-initrd", "${initramfs}",
+      "-append", "console=ttyS0 panic=-1",
+    ]))
+
+    machine = create_machine({"startCommand": flags})
+
+    machine.start()
+    machine.wait_for_console_text("roothash invalid or missing")
+  '';
+}))