Initial upgrade flow for control-plane

clitools/pkg/node/mounts.go

@@ -0,0 +1,194 @@
+package node
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	monov1alpha1 "example.com/monok8s/pkg/apis/monok8s/v1alpha1"
+	system "example.com/monok8s/pkg/system"
+	"k8s.io/klog/v2"
+)
+
+const (
+	altRootMount     = "/run/altrootfs"
+	altImageStoreSrc = "/run/altrootfs/usr/lib/monok8s/imagestore"
+)
+
+func MountAltImageStore(ctx context.Context, nctx *NodeContext) error {
+	// Make mountpoints first.
+	if err := os.MkdirAll(altRootMount, 0o755); err != nil {
+		return fmt.Errorf("mkdir %s: %w", altRootMount, err)
+	}
+
+	altDev := monov1alpha1.AltPartDeviceLink
+	if mounted, err := isMounted(altRootMount); err != nil {
+		return fmt.Errorf("check mount %s: %w", altRootMount, err)
+	} else if !mounted {
+		klog.InfoS("mounting alt rootfs", "device", altDev, "target", altRootMount)
+		if _, err := nctx.SystemRunner.RunWithOptions(
+			ctx,
+			"mount",
+			[]string{"-o", "ro", altDev, altRootMount},
+			system.RunOptions{Timeout: 30 * time.Second},
+		); err != nil {
+			return fmt.Errorf("mount alt rootfs %s on %s: %w", altDev, altRootMount, err)
+		}
+	}
+
+	// If the alt imagestore doesn't exist, don't fail hard unless you want strict behavior.
+	st, err := os.Stat(altImageStoreSrc)
+	if err != nil {
+
+		// Unmount immediately
+		_ = safeUnmount(ctx, nctx, altRootMount)
+
+		if os.IsNotExist(err) {
+			klog.InfoS(
+				"alt imagestore not found; proceeding without it",
+				"path", altImageStoreSrc,
+			)
+			err = writeCRIOStorageConfig(ctx, nctx, "")
+			if err != nil {
+				return err
+			}
+			return nil
+		}
+
+		return fmt.Errorf("stat alt imagestore %s: %w", altImageStoreSrc, err)
+	}
+
+	if !st.IsDir() {
+		return fmt.Errorf("alt imagestore exists but is not a directory: %s", altImageStoreSrc)
+	}
+
+	err = writeCRIOStorageConfig(ctx, nctx, altImageStoreSrc)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func UnmountAltImageStore(ctx context.Context, nctx *NodeContext) error {
+
+	mounted, err := isMounted(altRootMount)
+	if err != nil {
+		return err
+	}
+
+	if mounted {
+		if err := writeCRIOStorageConfig(ctx, nctx, ""); err != nil {
+			return err
+		}
+		err := RestartCRIO(ctx, nctx)
+		if err != nil {
+			return err
+		}
+	}
+
+	var errs []string
+
+	if err := safeUnmount(ctx, nctx, altRootMount); err != nil {
+		errs = append(errs, err.Error())
+	}
+
+	if len(errs) > 0 {
+		return fmt.Errorf(strings.Join(errs, "; "))
+	}
+	return nil
+}
+
+func isMounted(path string) (bool, error) {
+	f, err := os.Open("/proc/self/mountinfo")
+	if err != nil {
+		return false, fmt.Errorf("open /proc/self/mountinfo: %w", err)
+	}
+	defer f.Close()
+
+	target := filepath.Clean(path)
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if len(fields) < 5 {
+			continue
+		}
+
+		mountPoint, err := unescapeMountInfo(fields[4])
+		if err != nil {
+			return false, fmt.Errorf("decode mountpoint %q: %w", fields[4], err)
+		}
+
+		if filepath.Clean(mountPoint) == target {
+			return true, nil
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return false, fmt.Errorf("scan /proc/self/mountinfo: %w", err)
+	}
+
+	return false, nil
+}
+
+func safeUnmount(ctx context.Context, nctx *NodeContext, path string) error {
+	mounted, err := isMounted(path)
+	if err != nil {
+		return fmt.Errorf("check mountpoint %s: %w", path, err)
+	}
+	if !mounted {
+		return nil
+	}
+
+	klog.InfoS("unmounting", "target", path)
+	_, err = nctx.SystemRunner.RunWithOptions(
+		ctx,
+		"umount",
+		[]string{path},
+		system.RunOptions{Timeout: 30 * time.Second},
+	)
+	if err != nil {
+		return fmt.Errorf("umount %s: %w", path, err)
+	}
+	return nil
+}
+
+func unescapeMountInfo(s string) (string, error) {
+	var b strings.Builder
+	b.Grow(len(s))
+
+	for i := 0; i < len(s); i++ {
+		if s[i] != '\\' {
+			b.WriteByte(s[i])
+			continue
+		}
+
+		if i+3 >= len(s) {
+			return "", fmt.Errorf("truncated escape sequence")
+		}
+
+		esc := s[i+1 : i+4]
+		switch esc {
+		case "040":
+			b.WriteByte(' ')
+		case "011":
+			b.WriteByte('\t')
+		case "012":
+			b.WriteByte('\n')
+		case "134":
+			b.WriteByte('\\')
+		default:
+			return "", fmt.Errorf("unsupported escape sequence \\%s", esc)
+		}
+
+		i += 3
+	}
+
+	return b.String(), nil
+}