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package sources
import (
"crypto/sha256"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"os"
"path/filepath"
"regexp"
"strings"
"github.com/lxc/distrobuilder/shared"
)
type ubuntu struct {
common
fname string
fpath string
}
// Run downloads the tarball and unpacks it.
func (s *ubuntu) Run() error {
err := s.downloadImage(s.definition)
if err != nil {
return fmt.Errorf("Failed to download image: %w", err)
}
return s.unpack(filepath.Join(s.fpath, s.fname), s.rootfsDir)
}
func (s *ubuntu) downloadImage(definition shared.Definition) error {
var baseURL string
var err error
switch strings.ToLower(s.definition.Image.Variant) {
case "default":
baseURL = fmt.Sprintf("%s/releases/%s/release/", s.definition.Source.URL,
s.definition.Image.Release)
if strings.ContainsAny(s.definition.Image.Release, "0123456789") {
s.fname = fmt.Sprintf("ubuntu-base-%s-base-%s.tar.gz",
s.definition.Image.Release, s.definition.Image.ArchitectureMapped)
} else {
// if release is non-numerical, find the latest release
s.fname, err = s.getLatestRelease(baseURL,
s.definition.Image.Release, s.definition.Image.ArchitectureMapped)
if err != nil {
return fmt.Errorf("Failed to get latest release: %w", err)
}
}
case "core":
baseURL = fmt.Sprintf("%s/%s/stable/current/", s.definition.Source.URL, s.definition.Image.Release)
s.fname = fmt.Sprintf("ubuntu-core-%s-%s.img.xz", s.definition.Image.Release, s.definition.Image.ArchitectureMapped)
default:
return fmt.Errorf("Unknown Ubuntu variant %q", s.definition.Image.Variant)
}
url, err := url.Parse(baseURL)
if err != nil {
return fmt.Errorf("Failed to parse URL %q: %w", baseURL, err)
}
skip, err := s.validateGPGRequirements(url)
if err != nil {
return fmt.Errorf("Failed to validate GPG requirements: %w", err)
}
s.definition.Source.SkipVerification = skip
var fpath string
checksumFile := ""
if !s.definition.Source.SkipVerification {
checksumFile = baseURL + "SHA256SUMS"
fpath, err = s.DownloadHash(s.definition.Image, baseURL+"SHA256SUMS.gpg", "", nil)
if err != nil {
return fmt.Errorf("Failed to download %q: %w", baseURL+"SHA256SUMS.gpg", err)
}
_, err = s.DownloadHash(s.definition.Image, checksumFile, "", nil)
if err != nil {
return fmt.Errorf("Failed to download %q: %w", checksumFile, err)
}
valid, err := s.VerifyFile(
filepath.Join(fpath, "SHA256SUMS"),
filepath.Join(fpath, "SHA256SUMS.gpg"))
if err != nil {
return fmt.Errorf(`Failed to verify "SHA256SUMS": %w`, err)
}
if !valid {
return errors.New(`Invalid signature for "SHA256SUMS"`)
}
}
s.fpath, err = s.DownloadHash(s.definition.Image, baseURL+s.fname, checksumFile, sha256.New())
if err != nil {
return fmt.Errorf("Failed to download %q: %w", baseURL+s.fname, err)
}
return nil
}
func (s ubuntu) unpack(filePath, rootDir string) error {
err := os.RemoveAll(rootDir)
if err != nil {
return fmt.Errorf("Failed to remove directory %q: %w", rootDir, err)
}
err = os.MkdirAll(rootDir, 0o755)
if err != nil {
return fmt.Errorf("Failed to create directory %q: %w", rootDir, err)
}
s.logger.WithField("file", filePath).Info("Unpacking image")
err = shared.Unpack(filePath, rootDir)
if err != nil {
return fmt.Errorf("Failed to unpack %q: %w", filePath, err)
}
return nil
}
func (s ubuntu) getLatestRelease(baseURL, release, arch string) (string, error) {
var (
resp *http.Response
err error
)
err = shared.Retry(func() error {
resp, err = s.client.Get(baseURL)
if err != nil {
return fmt.Errorf("Failed to GET %q: %w", baseURL, err)
}
return nil
}, 3)
if err != nil {
return "", err
}
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
if err != nil {
return "", fmt.Errorf("Failed to read body: %w", err)
}
regex := regexp.MustCompile(fmt.Sprintf("ubuntu-base-\\d{2}\\.\\d{2}(\\.\\d+)?-base-%s.tar.gz", arch))
releases := regex.FindAllString(string(body), -1)
if len(releases) > 1 {
return string(releases[len(releases)-1]), nil
}
return "", errors.New("Failed to find latest release")
}
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