libct/int: remove logger from init

Currently, TestInit sets up logrus, and init uses it to log an error
from StartInitialization(). This is solely used by TestExecInError
to check that error returned from StartInitialization is the one it
expects.

Note that the very same error is communicated to the runc init parent
and is ultimately returned by container.Run(), so checking what
StartInitialization returned is redundant.

Remove logrus setup and use from TestMain/init.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/integration/execin_test.go

@@ -215,12 +215,10 @@ func TestExecInError(t *testing.T) {
 	ok(t, err)
 
 	for i := 0; i < 42; i++ {
-		var out bytes.Buffer
 		unexistent := &libcontainer.Process{
-			Cwd:    "/",
-			Args:   []string{"unexistent"},
-			Env:    standardEnvironment,
-			Stderr: &out,
+			Cwd:  "/",
+			Args: []string{"unexistent"},
+			Env:  standardEnvironment,
 		}
 		err = container.Run(unexistent)
 		if err == nil {
@@ -229,9 +227,6 @@ func TestExecInError(t *testing.T) {
 		if !strings.Contains(err.Error(), "executable file not found") {
 			t.Fatalf("Should be error about not found executable, got %s", err)
 		}
-		if !bytes.Contains(out.Bytes(), []byte("executable file not found")) {
-			t.Fatalf("executable file not found error not delivered to stdio:\n%s", out.String())
-		}
 	}
 }
 

libcontainer/integration/init_test.go

@@ -1,6 +1,7 @@
 package integration
 
 import (
+	"fmt"
 	"os"
 	"runtime"
 	"testing"
@@ -9,27 +10,27 @@ import (
 	//nolint:revive // Enable cgroup manager to manage devices
 	_ "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	_ "github.com/opencontainers/runc/libcontainer/nsenter"
-
-	"github.com/sirupsen/logrus"
 )
 
-// init runs the libcontainer initialization code because of the busybox style needs
-// to work around the go runtime and the issues with forking
+// Same as ../../init.go but for libcontainer/integration.
 func init() {
 	if len(os.Args) < 2 || os.Args[1] != "init" {
 		return
 	}
+	// This is the golang entry point for runc init, executed
+	// before TestMain() but after libcontainer/nsenter's nsexec().
 	runtime.GOMAXPROCS(1)
 	runtime.LockOSThread()
 	if err := libcontainer.StartInitialization(); err != nil {
-		logrus.Fatal(err)
+		// logrus is not initialized
+		fmt.Fprintln(os.Stderr, err)
 	}
+	// Normally, StartInitialization() never returns, meaning
+	// if we are here, it had failed.
+	os.Exit(1)
 }
 
 func TestMain(m *testing.M) {
-	logrus.SetOutput(os.Stderr)
-	logrus.SetLevel(logrus.InfoLevel)
-
 	ret := m.Run()
 	os.Exit(ret)
 }