nvidia-container-toolkit: only mount existing paths in the host

nixos/modules/services/hardware/nvidia-container-toolkit/cdi-generate.nix

@@ -13,11 +13,14 @@
     inherit hostPath containerPath;
     options = mountOptions;
   };
-  jqAddMountExpression = ".containerEdits.mounts[.containerEdits.mounts | length] |= . +";
-  allJqMounts = lib.concatMap
-    (mount:
-      ["${lib.getExe jq} '${jqAddMountExpression} ${builtins.toJSON (mkMount mount)}'"])
-    mounts;
+  mountToCommand = mount:
+    "additionalMount \"${mount.hostPath}\" \"${mount.containerPath}\" '${builtins.toJSON mount.mountOptions}'";
+  mountsToCommands = mounts:
+    if (builtins.length mounts) == 0 then
+      "cat"
+    else
+      (lib.strings.concatMapStringsSep " | \\\n"
+        mountToCommand mounts);
 in
 writeScriptBin "nvidia-cdi-generator"
 ''
@@ -32,6 +35,18 @@ function cdiGenerate {
     --nvidia-ctk-path ${lib.getExe' nvidia-container-toolkit "nvidia-ctk"}
 }
 
-cdiGenerate | \
-  ${lib.concatStringsSep " | " allJqMounts} > $RUNTIME_DIRECTORY/nvidia-container-toolkit.json
+function additionalMount {
+  local hostPath="$1"
+  local containerPath="$2"
+  local mountOptions="$3"
+  if [ -e "$hostPath" ]; then
+    ${lib.getExe jq} ".containerEdits.mounts[.containerEdits.mounts | length] = { \"hostPath\": \"$hostPath\", \"containerPath\": \"$containerPath\", \"options\": $mountOptions }"
+  else
+    echo "Mount $hostPath ignored: could not find path in the host machine" >&2
+    cat
+  fi
+}
+
+cdiGenerate |
+  ${mountsToCommands mounts} > $RUNTIME_DIRECTORY/nvidia-container-toolkit.json
 ''

nixos/modules/services/hardware/nvidia-container-toolkit/default.nix

@@ -71,6 +71,8 @@
           /usr/local/nvidia/lib64.
         '';
       };
+
+      package = lib.mkPackageOption pkgs "nvidia-container-toolkit" { };
     };
 
   };
@@ -129,6 +131,7 @@
           let
             script = pkgs.callPackage ./cdi-generate.nix {
               inherit (config.hardware.nvidia-container-toolkit) mounts;
+              nvidia-container-toolkit = config.hardware.nvidia-container-toolkit.package;
               nvidia-driver = config.hardware.nvidia.package;
               deviceNameStrategy = config.hardware.nvidia-container-toolkit.device-name-strategy;
             };

nixos/tests/all-tests.nix

@@ -699,6 +699,7 @@ in {
   ntfy-sh = handleTest ./ntfy-sh.nix {};
   ntfy-sh-migration = handleTest ./ntfy-sh-migration.nix {};
   ntpd-rs = handleTest ./ntpd-rs.nix {};
+  nvidia-container-toolkit = handleTest ./nvidia-container-toolkit.nix {};
   nvmetcfg = handleTest ./nvmetcfg.nix {};
   nzbget = handleTest ./nzbget.nix {};
   nzbhydra2 = handleTest ./nzbhydra2.nix {};

nixos/tests/nvidia-container-toolkit.nix

@@ -0,0 +1,177 @@
+import ./make-test-python.nix (
+  {
+    pkgs,
+    lib,
+    system,
+    ...
+  }:
+  let
+    testContainerImage =
+      let
+        testCDIScript = pkgs.writeShellScriptBin "test-cdi" ''
+          die() {
+            echo "$1"
+            exit 1
+          }
+
+          check_file_referential_integrity() {
+            echo "checking $1 referential integrity"
+            ( ${pkgs.glibc.bin}/bin/ldd "$1" | ${lib.getExe pkgs.gnugrep} "not found" &> /dev/null ) && return 1
+            return 0
+          }
+
+          check_directory_referential_integrity() {
+            ${lib.getExe pkgs.findutils} "$1" -type f -print0 | while read -d $'\0' file; do
+              if [[ $(${lib.getExe pkgs.file} "$file" | ${lib.getExe pkgs.gnugrep} ELF) ]]; then
+                check_file_referential_integrity "$file" || exit 1
+              else
+                echo "skipping $file: not an ELF file"
+              fi
+            done
+          }
+
+          check_directory_referential_integrity "/usr/bin" || exit 1
+          check_directory_referential_integrity "${pkgs.addDriverRunpath.driverLink}" || exit 1
+          check_directory_referential_integrity "/usr/local/nvidia" || exit 1
+        '';
+      in
+      pkgs.dockerTools.buildImage {
+        name = "cdi-test";
+        tag = "latest";
+        config = {
+          Cmd = [ "${testCDIScript}/bin/test-cdi" ];
+        };
+        copyToRoot = (
+          with pkgs.dockerTools;
+          [
+            usrBinEnv
+            binSh
+          ]
+        );
+      };
+    emptyCDISpec = ''
+      #! ${pkgs.runtimeShell}
+      cat <<CDI_DOCUMENT
+        {
+          "cdiVersion": "0.5.0",
+          "kind": "nvidia.com/gpu",
+          "devices": [
+            {
+              "name": "all",
+              "containerEdits": {
+                "deviceNodes": [
+                  {
+                    "path": "/dev/urandom"
+                  }
+                ],
+                "hooks": [],
+                "mounts": []
+              }
+            }
+          ],
+          "containerEdits": {
+            "deviceNodes": [],
+            "hooks": [],
+            "mounts": []
+          }
+        }
+      CDI_DOCUMENT
+    '';
+    nvidia-container-toolkit = {
+      enable = true;
+      package = pkgs.stdenv.mkDerivation {
+        name = "nvidia-ctk-dummy";
+        version = "1.0.0";
+        dontUnpack = true;
+        dontBuild = true;
+        installPhase = ''
+          mkdir -p $out/bin
+          cat <<EOF > $out/bin/nvidia-ctk
+            ${emptyCDISpec}
+          EOF
+          chmod +x $out/bin/nvidia-ctk
+        '';
+      };
+    };
+  in
+  {
+    name = "nvidia-container-toolkit";
+    meta = with lib.maintainers; {
+      maintainers = [ ereslibre ];
+    };
+    nodes = {
+      no-nvidia-gpus =
+        { config, ... }:
+        {
+          environment.systemPackages = with pkgs; [ jq ];
+          hardware = {
+            inherit nvidia-container-toolkit;
+            nvidia = {
+              open = true;
+              package = config.boot.kernelPackages.nvidiaPackages.stable.open;
+            };
+          };
+        };
+
+      nvidia-one-gpu =
+        { config, pkgs, ... }:
+        {
+          virtualisation.diskSize = 10240;
+          environment.systemPackages = with pkgs; [
+            jq
+            podman
+          ];
+          hardware = {
+            inherit nvidia-container-toolkit;
+            nvidia = {
+              open = true;
+              package = config.boot.kernelPackages.nvidiaPackages.stable.open;
+            };
+            opengl.enable = true;
+          };
+          virtualisation.containers.enable = true;
+        };
+
+      nvidia-one-gpu-invalid-host-paths =
+        { config, pkgs, ... }:
+        {
+          virtualisation.diskSize = 10240;
+          environment.systemPackages = with pkgs; [ jq ];
+          hardware = {
+            nvidia-container-toolkit = nvidia-container-toolkit // {
+              mounts = [
+                {
+                  hostPath = "/non-existant-path";
+                  containerPath = "/some/path";
+                }
+              ];
+            };
+            nvidia = {
+              open = true;
+              package = config.boot.kernelPackages.nvidiaPackages.stable.open;
+            };
+            opengl.enable = true;
+          };
+          virtualisation.containers.enable = true;
+        };
+    };
+    testScript = ''
+      start_all()
+
+      with subtest("Generate an empty CDI spec for a machine with no Nvidia GPUs"):
+        no_nvidia_gpus.wait_for_unit("nvidia-container-toolkit-cdi-generator.service")
+        no_nvidia_gpus.succeed("cat /var/run/cdi/nvidia-container-toolkit.json | jq")
+
+      with subtest("Podman loads the generated CDI spec for a machine with an Nvidia GPU"):
+        nvidia_one_gpu.wait_for_unit("nvidia-container-toolkit-cdi-generator.service")
+        nvidia_one_gpu.succeed("cat /var/run/cdi/nvidia-container-toolkit.json | jq")
+        nvidia_one_gpu.succeed("podman load < ${testContainerImage}")
+        print(nvidia_one_gpu.succeed("podman run --pull=never --device=nvidia.com/gpu=all -v /run/opengl-driver:/run/opengl-driver:ro cdi-test:latest"))
+
+      # Issue: https://github.com/NixOS/nixpkgs/issues/319201
+      with subtest("The generated CDI spec skips specified non-existant paths in the host"):
+        nvidia_one_gpu_invalid_host_paths.wait_for_unit("nvidia-container-toolkit-cdi-generator.service")
+        nvidia_one_gpu_invalid_host_paths.fail("grep 'non-existant-path' /var/run/cdi/nvidia-container-toolkit.json")
+    '';
+  }
+)