Move the code for Ubuntu support into its own file

This will reduce the size of the src/pkg/utils/utils.go file and make it
easier to specify which part of the code base is maintained by whom.

https://github.com/containers/toolbox/pull/1639

.github/CODEOWNERS

@@ -8,3 +8,4 @@
 /images/rhel       @debarshiray @olivergs
 /images/ubuntu     @Jmennius
 /src/pkg/utils/arch.go                    @Foxboron
+/src/pkg/utils/ubuntu.go                  @Jmennius

src/pkg/utils/ubuntu.go

@@ -0,0 +1,82 @@
+/*
+ * Copyright © 2023 – 2025 Red Hat Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package utils
+
+import (
+	"strconv"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/sirupsen/logrus"
+)
+
+func getDefaultReleaseUbuntu() (string, error) {
+	release, err := getHostVersionID()
+	if err != nil {
+		return "", err
+	}
+
+	return release, nil
+}
+
+func getFullyQualifiedImageUbuntu(image, release string) string {
+	imageFull := "quay.io/toolbx/" + image
+	return imageFull
+}
+
+func parseReleaseUbuntu(release string) (string, error) {
+	releaseParts := strings.Split(release, ".")
+	if len(releaseParts) != 2 {
+		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
+	}
+
+	releaseYear, err := strconv.Atoi(releaseParts[0])
+	if err != nil {
+		logrus.Debugf("Parsing release year %s as an integer failed: %s", releaseParts[0], err)
+		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
+	}
+
+	if releaseYear < 4 {
+		return "", &ParseReleaseError{"The release year must be 4 or more."}
+	}
+
+	releaseYearLen := utf8.RuneCountInString(releaseParts[0])
+	if releaseYearLen > 2 {
+		return "", &ParseReleaseError{"The release year cannot have more than two digits."}
+	} else if releaseYear < 10 && releaseYearLen == 2 {
+		return "", &ParseReleaseError{"The release year cannot have a leading zero."}
+	}
+
+	releaseMonth, err := strconv.Atoi(releaseParts[1])
+	if err != nil {
+		logrus.Debugf("Parsing release month %s as an integer failed: %s", releaseParts[1], err)
+		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
+	}
+
+	if releaseMonth < 1 {
+		return "", &ParseReleaseError{"The release month must be between 01 and 12."}
+	} else if releaseMonth > 12 {
+		return "", &ParseReleaseError{"The release month must be between 01 and 12."}
+	}
+
+	releaseMonthLen := utf8.RuneCountInString(releaseParts[1])
+	if releaseMonthLen != 2 {
+		return "", &ParseReleaseError{"The release month must have two digits."}
+	}
+
+	return release, nil
+}

src/pkg/utils/utils.go

@@ -28,7 +28,6 @@ import (
 	"strings"
 	"syscall"
 	"time"
-	"unicode/utf8"
 
 	"github.com/acobaugh/osrelease"
 	"github.com/containers/toolbox/pkg/shell"
@@ -328,15 +327,6 @@ func getDefaultReleaseForDistro(distro string) (string, error) {
 	return release, nil
 }
 
-func getDefaultReleaseUbuntu() (string, error) {
-	release, err := getHostVersionID()
-	if err != nil {
-		return "", err
-	}
-
-	return release, nil
-}
-
 func GetEnvOptionsForPreservedVariables() []string {
 	logrus.Debug("Creating list of environment variables to forward")
 
@@ -397,11 +387,6 @@ func GetFullyQualifiedImageFromDistros(image, release string) (string, error) {
 	return "", fmt.Errorf("failed to resolve image %s", image)
 }
 
-func getFullyQualifiedImageUbuntu(image, release string) string {
-	imageFull := "quay.io/toolbx/" + image
-	return imageFull
-}
-
 // GetGroupForSudo returns the name of the sudoers group.
 //
 // Some distros call it 'sudo' (eg. Ubuntu) and some call it 'wheel' (eg. Fedora).
@@ -712,49 +697,6 @@ func parseRelease(distro, release string) (string, error) {
 	return release, err
 }
 
-func parseReleaseUbuntu(release string) (string, error) {
-	releaseParts := strings.Split(release, ".")
-	if len(releaseParts) != 2 {
-		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
-	}
-
-	releaseYear, err := strconv.Atoi(releaseParts[0])
-	if err != nil {
-		logrus.Debugf("Parsing release year %s as an integer failed: %s", releaseParts[0], err)
-		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
-	}
-
-	if releaseYear < 4 {
-		return "", &ParseReleaseError{"The release year must be 4 or more."}
-	}
-
-	releaseYearLen := utf8.RuneCountInString(releaseParts[0])
-	if releaseYearLen > 2 {
-		return "", &ParseReleaseError{"The release year cannot have more than two digits."}
-	} else if releaseYear < 10 && releaseYearLen == 2 {
-		return "", &ParseReleaseError{"The release year cannot have a leading zero."}
-	}
-
-	releaseMonth, err := strconv.Atoi(releaseParts[1])
-	if err != nil {
-		logrus.Debugf("Parsing release month %s as an integer failed: %s", releaseParts[1], err)
-		return "", &ParseReleaseError{"The release must be in the 'YY.MM' format."}
-	}
-
-	if releaseMonth < 1 {
-		return "", &ParseReleaseError{"The release month must be between 01 and 12."}
-	} else if releaseMonth > 12 {
-		return "", &ParseReleaseError{"The release month must be between 01 and 12."}
-	}
-
-	releaseMonthLen := utf8.RuneCountInString(releaseParts[1])
-	if releaseMonthLen != 2 {
-		return "", &ParseReleaseError{"The release month must have two digits."}
-	}
-
-	return release, nil
-}
-
 // PathExists wraps around os.Stat providing a nice interface for checking an existence of a path.
 func PathExists(path string) bool {
 	if _, err := os.Stat(path); !errors.Is(err, os.ErrNotExist) {