mirror of
https://github.com/restic/restic.git
synced 2024-08-29 05:06:02 +02:00
179 lines
3.6 KiB
Go
179 lines
3.6 KiB
Go
package selfupdate
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import (
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"archive/zip"
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"bufio"
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"bytes"
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"compress/bzip2"
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"context"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"runtime"
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"strings"
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"github.com/pkg/errors"
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)
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func findHash(buf []byte, filename string) (hash []byte, err error) {
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sc := bufio.NewScanner(bytes.NewReader(buf))
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for sc.Scan() {
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data := strings.Split(sc.Text(), " ")
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if len(data) != 2 {
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continue
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}
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if data[1] == filename {
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h, err := hex.DecodeString(data[0])
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if err != nil {
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return nil, err
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}
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return h, nil
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}
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}
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return nil, fmt.Errorf("hash for file %v not found", filename)
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}
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func extractToFile(buf []byte, filename, target string, printf func(string, ...interface{})) error {
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var mode = os.FileMode(0755)
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// get information about the target file
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fi, err := os.Lstat(target)
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if err == nil {
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mode = fi.Mode()
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}
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var rd io.Reader = bytes.NewReader(buf)
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switch filepath.Ext(filename) {
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case ".bz2":
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rd = bzip2.NewReader(rd)
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case ".zip":
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zrd, err := zip.NewReader(bytes.NewReader(buf), int64(len(buf)))
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if err != nil {
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return err
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}
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if len(zrd.File) != 1 {
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return errors.New("ZIP archive contains more than one file")
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}
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file, err := zrd.File[0].Open()
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if err != nil {
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return err
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}
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defer func() {
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_ = file.Close()
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}()
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rd = file
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}
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err = os.Remove(target)
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if os.IsNotExist(err) {
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err = nil
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}
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if err != nil {
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return fmt.Errorf("unable to remove target file: %v", err)
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}
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dest, err := os.OpenFile(target, os.O_CREATE|os.O_EXCL|os.O_WRONLY, mode)
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if err != nil {
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return err
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}
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n, err := io.Copy(dest, rd)
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if err != nil {
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_ = dest.Close()
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_ = os.Remove(dest.Name())
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return err
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}
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err = dest.Close()
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if err != nil {
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return err
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}
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printf("saved %d bytes in %v\n", n, dest.Name())
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return nil
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}
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// DownloadLatestStableRelease downloads the latest stable released version of
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// restic and saves it to target. It returns the version string for the newest
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// version. The function printf is used to print progress information.
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func DownloadLatestStableRelease(ctx context.Context, target, currentVersion string, printf func(string, ...interface{})) (version string, err error) {
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if printf == nil {
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printf = func(string, ...interface{}) {}
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}
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printf("find latest release of restic at GitHub\n")
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rel, err := GitHubLatestRelease(ctx, "restic", "restic")
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if err != nil {
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return "", err
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}
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if rel.Version == currentVersion {
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printf("restic is up to date\n")
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return currentVersion, nil
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}
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printf("latest version is %v\n", rel.Version)
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_, sha256sums, err := getGithubDataFile(ctx, rel.Assets, "SHA256SUMS", printf)
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if err != nil {
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return "", err
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}
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_, sig, err := getGithubDataFile(ctx, rel.Assets, "SHA256SUMS.asc", printf)
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if err != nil {
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return "", err
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}
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ok, err := GPGVerify(sha256sums, sig)
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if err != nil {
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return "", err
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}
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if !ok {
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return "", errors.New("GPG signature verification of the file SHA256SUMS failed")
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}
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printf("GPG signature verification succeeded\n")
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ext := "bz2"
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if runtime.GOOS == "windows" {
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ext = "zip"
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}
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suffix := fmt.Sprintf("%s_%s.%s", runtime.GOOS, runtime.GOARCH, ext)
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downloadFilename, buf, err := getGithubDataFile(ctx, rel.Assets, suffix, printf)
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if err != nil {
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return "", err
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}
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printf("downloaded %v\n", downloadFilename)
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wantHash, err := findHash(sha256sums, downloadFilename)
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if err != nil {
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return "", err
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}
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gotHash := sha256.Sum256(buf)
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if !bytes.Equal(wantHash, gotHash[:]) {
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return "", fmt.Errorf("SHA256 hash mismatch, want hash %02x, got %02x", wantHash, gotHash)
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}
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err = extractToFile(buf, downloadFilename, target, printf)
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if err != nil {
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return "", err
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}
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return rel.Version, nil
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}
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