container: use more reliable nonexistence

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/container.go

@@ -17,6 +17,12 @@ import (
 	"hakurei.app/container/seccomp"
 )
 
+const (
+	// Nonexistent is a path that cannot exist.
+	// /proc is chosen because a system with covered /proc is unsupported by this package.
+	Nonexistent = "/proc/nonexistent"
+)
+
 type (
 	// Container represents a container environment being prepared or run.
 	// None of [Container] methods are safe for concurrent use.

container/seccomp/libseccomp_test.go

@@ -79,7 +79,7 @@ func TestExport(t *testing.T) {
 
 func BenchmarkExport(b *testing.B) {
 	buf := make([]byte, 8)
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		e := New(
 			Preset(PresetExt|PresetDenyNS|PresetDenyTTY|PresetDenyDevel|PresetLinux32,
 				AllowMultiarch|AllowCAN|AllowBluetooth),