container/std: relocate rule types

This enables its use in hst for #15.

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

container/seccomp/std_test.go

@@ -0,0 +1,63 @@
+package seccomp
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+
+	"hakurei.app/container/std"
+)
+
+func TestSyscallResolveName(t *testing.T) {
+	t.Parallel()
+
+	for name, want := range std.Syscalls() {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			// this checks the std implementation against libseccomp.
+			if got, ok := syscallResolveName(name); !ok || got != want {
+				t.Errorf("syscallResolveName(%q) = %d, want %d", name, got, want)
+			}
+		})
+	}
+}
+
+func TestRuleType(t *testing.T) {
+	assertKind[std.ScmpUint, scmpUint](t)
+	assertKind[std.ScmpInt, scmpInt](t)
+
+	assertSize[std.NativeRule, syscallRule](t)
+	assertKind[std.ScmpDatum, scmpDatum](t)
+	assertKind[std.ScmpCompare, scmpCompare](t)
+	assertSize[std.ScmpArgCmp, scmpArgCmp](t)
+}
+
+// assertSize asserts that native and equivalent are of the same size.
+func assertSize[native, equivalent any](t *testing.T) {
+	t.Helper()
+
+	got, want := unsafe.Sizeof(*new(native)), unsafe.Sizeof(*new(equivalent))
+	if got != want {
+		t.Fatalf("%s: %d, want %d", reflect.TypeFor[native]().Name(), got, want)
+	}
+}
+
+// assertKind asserts that native and equivalent are of the same kind.
+func assertKind[native, equivalent any](t *testing.T) {
+	t.Helper()
+
+	assertSize[native, equivalent](t)
+	nativeType, equivalentType := reflect.TypeFor[native](), reflect.TypeFor[equivalent]()
+	got, want := nativeType.Kind(), equivalentType.Kind()
+
+	if got == reflect.Invalid || want == reflect.Invalid {
+		t.Fatalf("%s: invalid call to assertKind", nativeType.Name())
+	}
+	if got == reflect.Struct {
+		t.Fatalf("%s: struct is unsupported by assertKind", nativeType.Name())
+	}
+	if got != want {
+		t.Fatalf("%s: %s, want %s", nativeType.Name(), nativeType.Kind(), equivalentType.Kind())
+	}
+}