Add XDG override for config directory

Signed-off-by: Renaud Gaubert <rgaubert@nvidia.com>

runtime/src/main.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"os"
 	"os/exec"
+	"path"
 	"strings"
 	"syscall"
 
@@ -15,10 +16,16 @@ import (
 )
 
 const (
-	configFilePath      = "/etc/nvidia-container-runtime/config.toml"
+	configOverride      = "XDG_CONFIG_HOME"
+	configFilePath      = "nvidia-container-runtime/config.toml"
+
 	hookDefaultFilePath = "/usr/bin/nvidia-container-runtime-hook"
 )
 
+var (
+	configDir           = "/etc/"
+)
+
 var fileLogger *log.Logger = nil
 
 type args struct {
@@ -33,6 +40,12 @@ type config struct {
 func getConfig() (*config, error) {
 	cfg := &config{}
 
+	if XDGConfigDir := os.Getenv(configOverride); len(XDGConfigDir) != 0 {
+		configDir = XDGConfigDir
+	}
+
+	configFilePath := path.Join(configDir, configFilePath)
+
 	tomlContent, err := ioutil.ReadFile(configFilePath)
 	if err != nil {
 		return nil, err
@@ -128,7 +141,6 @@ func addNVIDIAHook(spec *specs.Spec) error {
 }
 
 func main() {
-
 	cfg, err := getConfig()
 	exitOnError(err, "fail to get config")
 

runtime/src/main_test.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
@@ -192,3 +193,24 @@ func nvidiaHookCount(hooks *specs.Hooks) int {
 	}
 	return count
 }
+
+func TestGetConfigWithCustomConfig(t *testing.T) {
+	wd, err := os.Getwd()
+	require.NoError(t, err)
+
+	// By default debug is disabled
+	contents := []byte("[nvidia-container-runtime]\ndebug = \"/nvidia-container-toolkit.log\"")
+	testDir := path.Join(wd, "test")
+	filename :=  path.Join(testDir, configFilePath)
+
+	os.Setenv(configOverride, testDir)
+
+	require.NoError(t, os.MkdirAll(filepath.Dir(filename), 0766))
+	require.NoError(t, ioutil.WriteFile(filename, contents, 0766))
+
+	defer func() { require.NoError(t, os.RemoveAll(testDir)) } ()
+
+	cfg, err := getConfig()
+	require.NoError(t, err)
+	require.Equal(t, cfg.debugFilePath, "/nvidia-container-toolkit.log")
+}