Comments addressed.

Author: liulanze

toolkit/tools/internal/osinfo/osinfo.go

@@ -1,6 +1,8 @@
 package osinfo
 
 import (
+	"errors"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -10,6 +12,9 @@ import (
 func GetDistroAndVersion(rootDir string) (string, string) {
 	output, err := os.ReadFile(filepath.Join(rootDir, "etc/os-release"))
 	if err != nil {
+		if !errors.Is(err, fs.ErrNotExist) {
+			return "Unknown Distro", "Unknown Version"
+		}
 		// Fall back to /usr/lib/os-release per the os-release(5) spec.
 		output, err = os.ReadFile(filepath.Join(rootDir, "usr/lib/os-release"))
 		if err != nil {

toolkit/tools/internal/targetos/targetos.go

@@ -4,7 +4,9 @@
 package targetos
 
 import (
+	"errors"
 	"fmt"
+	"io/fs"
 	"path/filepath"
 	"strings"
 
@@ -26,6 +28,9 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 	// Try /etc/os-release first, then fall back to /usr/lib/os-release.
 	fields, err := envfile.ParseEnvFile(filepath.Join(rootfs, "etc/os-release"))
 	if err != nil {
+		if !errors.Is(err, fs.ErrNotExist) {
+			return "", fmt.Errorf("failed to read /etc/os-release:\n%w", err)
+		}
 		fields, err = envfile.ParseEnvFile(filepath.Join(rootfs, "usr/lib/os-release"))
 		if err != nil {
 			return "", fmt.Errorf("failed to read os-release (tried /etc/os-release and /usr/lib/os-release):\n%w", err)
@@ -42,7 +47,7 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 			return TargetOsAzureLinux2, nil
 
 		default:
-			return "", fmt.Errorf("unknown VERSION_ID (%s) for CBL-Mariner in /etc/os-release", versionId)
+			return "", fmt.Errorf("unknown VERSION_ID (%s) for CBL-Mariner in os-release", versionId)
 		}
 
 	case "azurelinux":
@@ -53,7 +58,7 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 			// ACL uses VERSION_ID like "3.0.YYYYMMDD" (e.g. "3.0.20260421").
 			// Accept any version that starts with "3.0".
 			if !strings.HasPrefix(versionId, "3.0") {
-				return "", fmt.Errorf("unknown VERSION_ID (%s) for Azure Container Linux in /etc/os-release", versionId)
+				return "", fmt.Errorf("unknown VERSION_ID (%s) for Azure Container Linux in os-release", versionId)
 			}
 			return TargetOsAcl, nil
 
@@ -64,11 +69,11 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 				return TargetOsAzureLinux3, nil
 
 			default:
-				return "", fmt.Errorf("unknown VERSION_ID (%s) for Azure Linux in /etc/os-release", versionId)
+				return "", fmt.Errorf("unknown VERSION_ID (%s) for Azure Linux in os-release", versionId)
 			}
 
 		default:
-			return "", fmt.Errorf("unknown VARIANT_ID (%s) for Azure Linux in /etc/os-release", variantId)
+			return "", fmt.Errorf("unknown VARIANT_ID (%s) for Azure Linux in os-release", variantId)
 		}
 
 	case "fedora":
@@ -77,7 +82,7 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 			return TargetOsFedora42, nil
 
 		default:
-			return "", fmt.Errorf("unknown VERSION_ID (%s) for Fedora in /etc/os-release", versionId)
+			return "", fmt.Errorf("unknown VERSION_ID (%s) for Fedora in os-release", versionId)
 		}
 
 	case "ubuntu":
@@ -89,10 +94,10 @@ func GetInstalledTargetOs(rootfs string) (TargetOs, error) {
 			return TargetOsUbuntu2404, nil
 
 		default:
-			return "", fmt.Errorf("unknown VERSION_ID (%s) for Ubuntu in /etc/os-release", versionId)
+			return "", fmt.Errorf("unknown VERSION_ID (%s) for Ubuntu in os-release", versionId)
 		}
 
 	default:
-		return "", fmt.Errorf("unknown ID (%s) in /etc/os-release", distroId)
+		return "", fmt.Errorf("unknown ID (%s) in os-release", distroId)
 	}
 }

toolkit/tools/pkg/imagecustomizerlib/cosicommon.go

@@ -429,7 +429,7 @@ func extractUkiEntriesIfPresent(chrootDir, buildDir string, distroHandler Distro
 
 	var entries []SystemDBootEntry
 	for kernelName, cmdline := range cmdlines {
-		efiPath := filepath.Join("/"+distroHandler.GetEspDir(), "EFI/Linux", fmt.Sprintf("%s.efi", kernelName))
+		efiPath := filepath.Join("/", distroHandler.GetEspDir(), "EFI/Linux", fmt.Sprintf("%s.efi", kernelName))
 		kernelVersion, err := getKernelVersion(kernelName)
 		if err != nil {
 			return nil, fmt.Errorf("invalid kernel name in UKI file (%s):\n%w", kernelName, err)

toolkit/tools/pkg/imagecustomizerlib/customizeuki_test.go

@@ -566,3 +566,45 @@ func getUkiAddonFiles(espPath string) ([]string, error) {
 
 	return addonFiles, nil
 }
+
+func TestGetKernelNameFromUki(t *testing.T) {
+	tests := []struct {
+		name        string
+		ukiPath     string
+		expected    string
+		expectError bool
+	}{
+		{
+			name:     "standard vmlinuz naming",
+			ukiPath:  "/boot/efi/EFI/Linux/vmlinuz-6.6.51.1-5.azl3.efi",
+			expected: "vmlinuz-6.6.51.1-5.azl3",
+		},
+		{
+			name:     "non-standard naming (ACL)",
+			ukiPath:  "/boot/EFI/Linux/acl.efi",
+			expected: "acl",
+		},
+		{
+			name:     "non-standard naming with path",
+			ukiPath:  "/some/path/custom-kernel.efi",
+			expected: "custom-kernel",
+		},
+		{
+			name:        "no .efi extension",
+			ukiPath:     "/boot/EFI/Linux/vmlinuz-6.6.51",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := getKernelNameFromUki(tt.ukiPath)
+			if tt.expectError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.expected, result)
+			}
+		})
+	}
+}

toolkit/tools/pkg/imagecustomizerlib/distrohandler_acl.go

@@ -31,7 +31,25 @@ func (d *aclDistroHandler) GetTargetOs() targetos.TargetOs {
 }
 
 func (d *aclDistroHandler) ValidateConfig(rc *ResolvedConfig) error {
-	// TODO: Block unsupported operations (repartitioning, GRUB, initramfs regen, etc.)
+	// ACL Phase 0: only mount/recognize/passthrough is supported.
+	// Block operations that would fail with confusing errors later.
+
+	if rc.Storage.CustomizePartitions() {
+		return fmt.Errorf("storage repartitioning is not yet supported for ACL")
+	}
+
+	if rc.BootLoader.ResetType == imagecustomizerapi.ResetBootLoaderTypeHard {
+		return fmt.Errorf("bootloader hard-reset is not supported on ACL (ACL uses systemd-boot, not GRUB)")
+	}
+
+	if rc.Uki != nil && rc.Uki.Mode != imagecustomizerapi.UkiModePassthrough {
+		return fmt.Errorf("only UKI passthrough mode is currently supported for ACL (got %q)", rc.Uki.Mode)
+	}
+
+	if len(rc.OsKernelCommandLine.ExtraCommandLine) > 0 {
+		return fmt.Errorf("kernel command line modification is not yet supported for ACL")
+	}
+
 	return nil
 }
 

toolkit/tools/pkg/imagecustomizerlib/imageutils.go

@@ -391,6 +391,9 @@ func extractOSRelease(imageConnection *imageconnection.ImageConnection) (string,
 	osReleasePath := filepath.Join(imageConnection.Chroot().RootDir(), "etc/os-release")
 	data, err := file.Read(osReleasePath)
 	if err != nil {
+		if !errors.Is(err, fs.ErrNotExist) {
+			return "", fmt.Errorf("failed to read /etc/os-release:\n%w", err)
+		}
 		osReleasePath = filepath.Join(imageConnection.Chroot().RootDir(), "usr/lib/os-release")
 		data, err = file.Read(osReleasePath)
 		if err != nil {
@@ -418,9 +421,10 @@ func clearBtrfsReadOnlyProperties(imageConnection *imageconnection.ImageConnecti
 		mountPath := filepath.Join(imageConnection.Chroot().RootDir(), mp.GetTarget())
 
 		// Check if the subvolume is read-only.
-		stdout, _, err := shell.Execute("btrfs", "property", "get", "-ts", mountPath, "ro")
+		stdout, stderr, err := shell.Execute("btrfs", "property", "get", "-ts", mountPath, "ro")
 		if err != nil {
 			// Not all btrfs mounts have subvolumes; skip on error.
+			logger.Log.Debugf("Skipping btrfs property check on %s: %v: %s", mp.GetTarget(), err, stderr)
 			continue
 		}
 

toolkit/tools/pkg/imagecustomizerlib/partitionutils.go

@@ -203,8 +203,10 @@ func findFstabInRoot(diskPartition diskutils.PartitionInfo, tmpDir string) ([]st
 		matchingPaths = append(matchingPaths, "")
 	}
 
-	// ACL places an fstab at /usr/share/ic/etc/fstab on the USR partition. This
-	// path is outside the /etc overlay.
+	// Check for IC-specific fstab.
+	// ACL places an fstab at /usr/share/ic/etc/fstab on the USR partition so
+	// that IC can discover the partition layout without /etc being available.
+	// The path is unique enough to avoid false matches on non-ACL distros.
 	fstabIcPath := filepath.Join(tmpDir, "share/ic/etc/fstab")
 	exists, err = file.PathExists(fstabIcPath)
 	if err != nil {