// NewDigestVerifier returns a verifier that compares the written bytes
// against a passed in digest.
func NewDigestVerifier(d Digest) (Verifier, error) {
if err := d.Validate(); err != nil {
return nil, err
}
alg := d.Algorithm()
switch alg {
case "sha256", "sha384", "sha512":
return hashVerifier{
hash: alg.Hash(),
digest: d,
}, nil
default:
// Assume we have a tarsum.
version, err := tarsum.GetVersionFromTarsum(string(d))
if err != nil {
return nil, err
}
pr, pw := io.Pipe()
// TODO(stevvooe): We may actually want to ban the earlier versions of
// tarsum. That decision may not be the place of the verifier.
ts, err := tarsum.NewTarSum(pr, true, version)
if err != nil {
return nil, err
}
// TODO(sday): Ick! A goroutine per digest verification? We'll have to
// get the tarsum library to export an io.Writer variant.
go func() {
if _, err := io.Copy(ioutil.Discard, ts); err != nil {
pr.CloseWithError(err)
} else {
pr.Close()
}
}()
return &tarsumVerifier{
digest: d,
ts: ts,
pr: pr,
pw: pw,
}, nil
}
}
// ReadChecks takes the input and loads the hash/id to be checked
func ReadChecks(input io.Reader) (Checks, error) {
rdr := bufio.NewReader(input)
checks := Checks{}
for {
line, err := rdr.ReadString('\n')
if err != nil {
if err == io.EOF {
break
}
return checks, err
}
v, err := tarsum.GetVersionFromTarsum(line)
if err != nil {
continue
}
// tarsum+sha256:7b0ade22d5bba35d1e88389c005376f441e7d83bf5f363f2d7c70be9286163aa ./busybox.tar:120e218dd395ec314e7b6249f39d2853911b3d6def6ea164ae05722649f34b16
chunks := strings.SplitN(line, DefaultSpacer, 2)
sum, source := chunks[0], chunks[1]
i := strings.LastIndex(source, ":")
checks = append(checks, Check{Hash: sum, Source: source[:i], Id: strings.TrimSpace(source[i+1:]), Version: v})
}
return checks, nil
}
func main() {
var jobs []job
flag.Usage = usage
flag.Parse()
if showVersion {
version.PrintVersion()
return
}
var fail bool // if we fail on one item, foul the exit code
if flag.NArg() > 0 {
for _, path := range flag.Args() {
fp, err := os.Open(path)
if err != nil {
log.Printf("%s: %v", path, err)
fail = true
continue
}
defer fp.Close()
jobs = append(jobs, job{name: path, reader: fp})
}
} else {
// just read stdin
jobs = append(jobs, job{name: "-", reader: os.Stdin})
}
digestFn := algorithm.FromReader
if !algorithm.Available() {
// we cannot digest if is not available. An exception is made for
// tarsum.
if !strings.HasPrefix(algorithm.String(), "tarsum") {
unsupported()
}
var version tarsum.Version
if algorithm == "tarsum" {
// small hack: if we just have tarsum, use latest
version = tarsum.Version1
} else {
var err error
version, err = tarsum.GetVersionFromTarsum(algorithm.String())
if err != nil {
unsupported()
}
}
digestFn = func(rd io.Reader) (digest.Digest, error) {
ts, err := tarsum.NewTarSum(rd, true, version)
if err != nil {
return "", err
}
if _, err := io.Copy(ioutil.Discard, ts); err != nil {
return "", err
}
return digest.Digest(ts.Sum(nil)), nil
}
}
for _, job := range jobs {
dgst, err := digestFn(job.reader)
if err != nil {
log.Printf("%s: %v", job.name, err)
fail = true
continue
}
fmt.Printf("%v\t%s\n", dgst, job.name)
}
if fail {
os.Exit(1)
}
}