chore: handle grub option - "wipe"

This PR ensures that we can handle third grub option - "wipe". We will use it in 1.4.

For #6842

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>
(cherry picked from commit bfba367)

Author: Dmitriy Matrenichev

internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/boot_label.go

@@ -19,20 +19,23 @@ func FlipBootLabel(e BootLabel) (BootLabel, error) {
 		return BootB, nil
 	case BootB:
 		return BootA, nil
+	case BootReset:
+		fallthrough
 	default:
 		return "", fmt.Errorf("invalid entry: %s", e)
 	}
 }
 
 // ParseBootLabel parses the given human-readable boot label to a grub.BootLabel.
 func ParseBootLabel(name string) (BootLabel, error) {
-	if strings.HasPrefix(name, string(BootA)) {
+	switch {
+	case strings.HasPrefix(name, string(BootA)):
 		return BootA, nil
-	}
-
-	if strings.HasPrefix(name, string(BootB)) {
+	case strings.HasPrefix(name, string(BootB)):
 		return BootB, nil
+	case strings.HasPrefix(name, "Reset"):
+		return BootReset, nil
+	default:
+		return "", fmt.Errorf("could not parse boot entry from name: %s", name)
 	}
-
-	return "", fmt.Errorf("could not parse boot entry from name: %s", name)
 }

internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/constants.go

@@ -13,6 +13,9 @@ const (
 	// BootB is a bootloader label.
 	BootB BootLabel = "B"
 
+	// BootReset is a bootloader label.
+	BootReset BootLabel = "Reset"
+
 	// ConfigPath is the path to the grub config.
 	ConfigPath = constants.BootMountPoint + "/grub/grub.cfg"
 )

internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/decode.go

@@ -106,6 +106,10 @@ func parseEntries(conf []byte) (map[BootLabel]MenuEntry, error) {
 			return nil, err
 		}
 
+		if bootEntry == BootReset {
+			continue
+		}
+
 		entries[bootEntry] = MenuEntry{
 			Name:    name,
 			Linux:   linux,

internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/grub_test.go

@@ -77,6 +77,10 @@ func TestParseBootLabel(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, grub.BootB, label)
 
+	label, err = grub.ParseBootLabel("Reset Talos installation and return to maintenance mode\n")
+	assert.NoError(t, err)
+	assert.Equal(t, grub.BootReset, label)
+
 	_, err = grub.ParseBootLabel("C - v3")
 	assert.Error(t, err)
 }
@@ -94,7 +98,7 @@ func TestWrite(t *testing.T) {
 
 	tempFile, _ := os.CreateTemp("", "talos-test-grub-*.cfg")
 
-	defer os.Remove(tempFile.Name())
+	t.Cleanup(func() { require.NoError(t, os.Remove(tempFile.Name())) })
 
 	config := grub.NewConfig("cmdline A")
 

internal/app/machined/pkg/runtime/v1alpha1/bootloader/grub/testdata/grub_parse_test.cfg

@@ -20,3 +20,10 @@ menuentry "B - v2" {
   linux /B/vmlinuz cmdline B
   initrd /B/initramfs.xz
 }
+
+menuentry "Reset Talos installation and return to maintenance mode" {
+  set gfxmode=auto
+  set gfxpayload=text
+  linux /A/vmlinuz cmdline A talos.experimental.wipe=system:EPHEMERAL,STATE
+  initrd /A/initramfs.xz
+}