143 lines
3.0 KiB
Go
143 lines
3.0 KiB
Go
package shared
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import (
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"bufio"
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"fmt"
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"hash"
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"io"
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"io/ioutil"
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"net/http"
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"os"
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"path/filepath"
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"regexp"
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"strings"
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lxd "github.com/lxc/lxd/shared"
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"github.com/lxc/lxd/shared/ioprogress"
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)
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// DownloadHash downloads a file. If a checksum file is provided, it will try and
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// match the hash.
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func DownloadHash(file, checksum string, hashFunc hash.Hash) error {
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var (
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client http.Client
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hash string
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err error
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)
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if checksum != "" {
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if hashFunc != nil {
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hashFunc.Reset()
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}
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hashLen := 0
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if hashFunc != nil {
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hashLen = hashFunc.Size() * 2
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}
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hash, err = downloadChecksum(checksum, file, hashFunc, hashLen)
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if err != nil {
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return fmt.Errorf("Error while downloading checksum: %s", err)
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}
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}
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imagePath := filepath.Join(os.TempDir(), filepath.Base(file))
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stat, err := os.Stat(imagePath)
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if err == nil && stat.Size() > 0 {
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image, err := os.Open(imagePath)
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if err != nil {
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return err
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}
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defer image.Close()
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if checksum != "" {
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if hashFunc != nil {
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hashFunc.Reset()
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}
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_, err = io.Copy(hashFunc, image)
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if err != nil {
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return err
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}
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result := fmt.Sprintf("%x", hashFunc.Sum(nil))
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if result != hash {
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return fmt.Errorf("Hash mismatch for %s: %s != %s", imagePath, result, hash)
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}
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}
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return nil
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}
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image, err := os.Create(imagePath)
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if err != nil {
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return err
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}
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defer image.Close()
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progress := func(progress ioprogress.ProgressData) {
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fmt.Printf("%s\r", progress.Text)
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}
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if hashFunc != nil {
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hashFunc.Reset()
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}
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_, err = lxd.DownloadFileHash(&client, "", progress, nil, imagePath, file, hash, hashFunc, image)
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if err != nil {
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if checksum == "" && strings.HasPrefix(err.Error(), "Hash mismatch") {
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return nil
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}
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return err
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}
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fmt.Println("")
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return nil
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}
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// downloadChecksum downloads or opens URL, and matches fname against the
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// checksums inside of the downloaded or opened file.
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func downloadChecksum(URL string, fname string, hashFunc hash.Hash, hashLen int) (string, error) {
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var (
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client http.Client
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tempFile *os.File
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err error
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)
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// do not re-download checksum file if it's already present
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fi, err := os.Stat(filepath.Join(os.TempDir(), URL))
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if err == nil && !fi.IsDir() {
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tempFile, err = os.Open(filepath.Join(os.TempDir(), URL))
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if err != nil {
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return "", err
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}
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defer os.Remove(tempFile.Name())
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} else {
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tempFile, err = ioutil.TempFile(os.TempDir(), "hash.")
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if err != nil {
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return "", err
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}
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defer os.Remove(tempFile.Name())
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_, err = lxd.DownloadFileHash(&client, "", nil, nil, "", URL, "", hashFunc, tempFile)
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// ignore hash mismatch
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if err != nil && !strings.HasPrefix(err.Error(), "Hash mismatch") {
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return "", err
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}
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}
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tempFile.Seek(0, 0)
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scanner := bufio.NewScanner(tempFile)
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for scanner.Scan() {
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s := strings.Split(scanner.Text(), " ")
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matched, _ := regexp.MatchString(fmt.Sprintf(".*%s", filepath.Base(fname)), s[len(s)-1])
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if matched && (hashLen == 0 || hashLen == len(strings.TrimSpace(s[0]))) {
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return s[0], nil
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}
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}
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return "", fmt.Errorf("Could not find checksum")
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}
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