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package selfupdate
import (
"archive/zip"
"bufio"
"bytes"
"compress/bzip2"
"context"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"os"
"path/filepath"
"runtime"
"strings"
"github.com/pkg/errors"
)
func findHash(buf []byte, filename string) (hash []byte, err error) {
sc := bufio.NewScanner(bytes.NewReader(buf))
for sc.Scan() {
data := strings.Split(sc.Text(), " ")
if len(data) != 2 {
continue
}
if data[1] == filename {
h, err := hex.DecodeString(data[0])
if err != nil {
return nil, err
}
return h, nil
}
}
return nil, fmt.Errorf("hash for file %v not found", filename)
}
func extractToFile(buf []byte, filename, target string, printf func(string, ...interface{})) error {
var rd io.Reader = bytes.NewReader(buf)
switch filepath.Ext(filename) {
case ".bz2":
rd = bzip2.NewReader(rd)
case ".zip":
zrd, err := zip.NewReader(bytes.NewReader(buf), int64(len(buf)))
if err != nil {
return err
}
if len(zrd.File) != 1 {
return errors.New("ZIP archive contains more than one file")
}
file, err := zrd.File[0].Open()
if err != nil {
return err
}
defer func() {
_ = file.Close()
}()
rd = file
}
// Write everything to a temp file
dir := filepath.Dir(target)
new, err := os.CreateTemp(dir, "restic")
if err != nil {
return err
}
n, err := io.Copy(new, rd)
if err != nil {
_ = new.Close()
_ = os.Remove(new.Name())
return err
}
if err = new.Sync(); err != nil {
return err
}
if err = new.Close(); err != nil {
return err
}
mode := os.FileMode(0755)
// attempt to find the original mode
if fi, err := os.Lstat(target); err == nil {
mode = fi.Mode()
}
// Remove the original binary.
if err := removeResticBinary(dir, target); err != nil {
return err
}
// Rename the temp file to the final location atomically.
if err := os.Rename(new.Name(), target); err != nil {
return err
}
printf("saved %d bytes in %v\n", n, target)
return os.Chmod(target, mode)
}
// DownloadLatestStableRelease downloads the latest stable released version of
// restic and saves it to target. It returns the version string for the newest
// version. The function printf is used to print progress information.
func DownloadLatestStableRelease(ctx context.Context, target, currentVersion string, printf func(string, ...interface{})) (version string, err error) {
if printf == nil {
printf = func(string, ...interface{}) {}
}
printf("find latest release of restic at GitHub\n")
rel, err := GitHubLatestRelease(ctx, "restic", "restic")
if err != nil {
return "", err
}
if rel.Version == currentVersion {
printf("restic is up to date\n")
return currentVersion, nil
}
printf("latest version is %v\n", rel.Version)
_, sha256sums, err := getGithubDataFile(ctx, rel.Assets, "SHA256SUMS", printf)
if err != nil {
return "", err
}
_, sig, err := getGithubDataFile(ctx, rel.Assets, "SHA256SUMS.asc", printf)
if err != nil {
return "", err
}
ok, err := GPGVerify(sha256sums, sig)
if err != nil {
return "", err
}
if !ok {
return "", errors.New("GPG signature verification of the file SHA256SUMS failed")
}
printf("GPG signature verification succeeded\n")
ext := "bz2"
if runtime.GOOS == "windows" {
ext = "zip"
}
suffix := fmt.Sprintf("%s_%s.%s", runtime.GOOS, runtime.GOARCH, ext)
downloadFilename, buf, err := getGithubDataFile(ctx, rel.Assets, suffix, printf)
if err != nil {
return "", err
}
printf("downloaded %v\n", downloadFilename)
wantHash, err := findHash(sha256sums, downloadFilename)
if err != nil {
return "", err
}
gotHash := sha256.Sum256(buf)
if !bytes.Equal(wantHash, gotHash[:]) {
return "", fmt.Errorf("SHA256 hash mismatch, want hash %02x, got %02x", wantHash, gotHash)
}
err = extractToFile(buf, downloadFilename, target, printf)
if err != nil {
return "", err
}
return rel.Version, nil
}
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