// CopyFileWithTar emulates the behavior of the 'cp' command-line
// for a single file. It copies a regular file from path `src` to
// path `dst`, and preserves all its metadata.
//
// If `dst` ends with a trailing slash '/', the final destination path
// will be `dst/base(src)`.
func CopyFileWithTar(src, dst string) (err error) {
log.Debugf("CopyFileWithTar(%s, %s)", src, dst)
srcSt, err := os.Stat(src)
if err != nil {
return err
}
if srcSt.IsDir() {
return fmt.Errorf("Can't copy a directory")
}
// Clean up the trailing /
if dst[len(dst)-1] == '/' {
dst = path.Join(dst, filepath.Base(src))
}
// Create the holding directory if necessary
if err := os.MkdirAll(filepath.Dir(dst), 0700); err != nil && !os.IsExist(err) {
return err
}
r, w := io.Pipe()
errC := utils.Go(func() error {
defer w.Close()
srcF, err := os.Open(src)
if err != nil {
return err
}
defer srcF.Close()
hdr, err := tar.FileInfoHeader(srcSt, "")
if err != nil {
return err
}
hdr.Name = filepath.Base(dst)
tw := tar.NewWriter(w)
defer tw.Close()
if err := tw.WriteHeader(hdr); err != nil {
return err
}
if _, err := io.Copy(tw, srcF); err != nil {
return err
}
return nil
})
defer func() {
if er := <-errC; err != nil {
err = er
}
}()
return Untar(r, filepath.Dir(dst), nil)
}
// FIXME: this is duplicated from graph_test.go in the docker package.
func fakeTar() (io.ReadCloser, error) {
content := []byte("Hello world!\n")
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, name := range []string{"/etc/postgres/postgres.conf", "/etc/passwd", "/var/log/postgres/postgres.conf"} {
hdr := new(tar.Header)
hdr.Size = int64(len(content))
hdr.Name = name
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
tw.Write([]byte(content))
}
tw.Close()
return ioutil.NopCloser(buf), nil
}
// make a tar:
// * num is the number of files the tar should have
// * size is the bytes per file
// * isRand is whether the contents of the files should be a random chunk (otherwise it's all zeros)
// * realFile will write to a TempFile, instead of an in memory buffer
func sizedTar(opts sizedOptions) io.Reader {
var (
fh io.ReadWriter
err error
)
if opts.realFile {
fh, err = ioutil.TempFile("", "tarsum")
if err != nil {
return nil
}
} else {
fh = bytes.NewBuffer([]byte{})
}
tarW := tar.NewWriter(fh)
for i := int64(0); i < opts.num; i++ {
err := tarW.WriteHeader(&tar.Header{
Name: fmt.Sprintf("/testdata%d", i),
Mode: 0755,
Uid: 0,
Gid: 0,
Size: opts.size,
})
if err != nil {
return nil
}
var rBuf []byte
if opts.isRand {
rBuf = make([]byte, 8)
_, err = rand.Read(rBuf)
if err != nil {
return nil
}
} else {
rBuf = []byte{0, 0, 0, 0, 0, 0, 0, 0}
}
for i := int64(0); i < opts.size/int64(8); i++ {
tarW.Write(rBuf)
}
}
return fh
}
func ExportChanges(dir string, changes []Change) (Archive, error) {
reader, writer := io.Pipe()
tw := tar.NewWriter(writer)
go func() {
twBuf := bufio.NewWriterSize(nil, twBufSize)
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
for _, change := range changes {
if change.Kind == ChangeDelete {
whiteOutDir := filepath.Dir(change.Path)
whiteOutBase := filepath.Base(change.Path)
whiteOut := filepath.Join(whiteOutDir, ".wh."+whiteOutBase)
timestamp := time.Now()
hdr := &tar.Header{
Name: whiteOut[1:],
Size: 0,
ModTime: timestamp,
AccessTime: timestamp,
ChangeTime: timestamp,
}
if err := tw.WriteHeader(hdr); err != nil {
log.Debugf("Can't write whiteout header: %s", err)
}
} else {
path := filepath.Join(dir, change.Path)
if err := addTarFile(path, change.Path[1:], tw, twBuf); err != nil {
log.Debugf("Can't add file %s to tar: %s", path, err)
}
}
}
// Make sure to check the error on Close.
if err := tw.Close(); err != nil {
log.Debugf("Can't close layer: %s", err)
}
writer.Close()
}()
return reader, nil
}
// Generate generates a new archive from the content provided
// as input.
//
// `files` is a sequence of path/content pairs. A new file is
// added to the archive for each pair.
// If the last pair is incomplete, the file is created with an
// empty content. For example:
//
// Generate("foo.txt", "hello world", "emptyfile")
//
// The above call will return an archive with 2 files:
// * ./foo.txt with content "hello world"
// * ./empty with empty content
//
// FIXME: stream content instead of buffering
// FIXME: specify permissions and other archive metadata
func Generate(input ...string) (Archive, error) {
files := parseStringPairs(input...)
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, file := range files {
name, content := file[0], file[1]
hdr := &tar.Header{
Name: name,
Size: int64(len(content)),
}
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
if _, err := tw.Write([]byte(content)); err != nil {
return nil, err
}
}
if err := tw.Close(); err != nil {
return nil, err
}
return ioutil.NopCloser(buf), nil
}
func fakeTar() (io.Reader, error) {
uid := os.Getuid()
gid := os.Getgid()
content := []byte("Hello world!\n")
buf := new(bytes.Buffer)
tw := tar.NewWriter(buf)
for _, name := range []string{"/etc/postgres/postgres.conf", "/etc/passwd", "/var/log/postgres/postgres.conf"} {
hdr := new(tar.Header)
// Leaving these fields blank requires root privileges
hdr.Uid = uid
hdr.Gid = gid
hdr.Size = int64(len(content))
hdr.Name = name
if err := tw.WriteHeader(hdr); err != nil {
return nil, err
}
tw.Write([]byte(content))
}
tw.Close()
return buf, nil
}
// TarWithOptions creates an archive from the directory at `path`, only including files whose relative
// paths are included in `options.Includes` (if non-nil) or not in `options.Excludes`.
func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error) {
pipeReader, pipeWriter := io.Pipe()
compressWriter, err := CompressStream(pipeWriter, options.Compression)
if err != nil {
return nil, err
}
tw := tar.NewWriter(compressWriter)
go func() {
// In general we log errors here but ignore them because
// during e.g. a diff operation the container can continue
// mutating the filesystem and we can see transient errors
// from this
if options.Includes == nil {
options.Includes = []string{"."}
}
twBuf := bufio.NewWriterSize(nil, twBufSize)
for _, include := range options.Includes {
filepath.Walk(filepath.Join(srcPath, include), func(filePath string, f os.FileInfo, err error) error {
if err != nil {
log.Debugf("Tar: Can't stat file %s to tar: %s", srcPath, err)
return nil
}
relFilePath, err := filepath.Rel(srcPath, filePath)
if err != nil {
return nil
}
skip, err := utils.Matches(relFilePath, options.Excludes)
if err != nil {
log.Debugf("Error matching %s", relFilePath, err)
return err
}
if skip {
if f.IsDir() {
return filepath.SkipDir
}
return nil
}
if err := addTarFile(filePath, relFilePath, tw, twBuf); err != nil {
log.Debugf("Can't add file %s to tar: %s", srcPath, err)
}
return nil
})
}
// Make sure to check the error on Close.
if err := tw.Close(); err != nil {
log.Debugf("Can't close tar writer: %s", err)
}
if err := compressWriter.Close(); err != nil {
log.Debugf("Can't close compress writer: %s", err)
}
if err := pipeWriter.Close(); err != nil {
log.Debugf("Can't close pipe writer: %s", err)
}
}()
return pipeReader, nil
}
func (ts *TarSum) Read(buf []byte) (int, error) {
if ts.gz == nil {
ts.bufTar = bytes.NewBuffer([]byte{})
ts.bufGz = bytes.NewBuffer([]byte{})
ts.tarR = tar.NewReader(ts.Reader)
ts.tarW = tar.NewWriter(ts.bufTar)
if !ts.DisableCompression {
ts.gz = gzip.NewWriter(ts.bufGz)
} else {
ts.gz = &nopCloseFlusher{Writer: ts.bufGz}
}
ts.h = sha256.New()
ts.h.Reset()
ts.first = true
ts.sums = make(map[string]string)
}
if ts.finished {
return ts.bufGz.Read(buf)
}
var buf2 []byte
if len(buf) > 8192 {
buf2 = make([]byte, len(buf), cap(buf))
} else {
buf2 = ts.bufData[:len(buf)-1]
}
n, err := ts.tarR.Read(buf2)
if err != nil {
if err == io.EOF {
if _, err := ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
if !ts.first {
ts.sums[ts.currentFile] = hex.EncodeToString(ts.h.Sum(nil))
ts.h.Reset()
} else {
ts.first = false
}
currentHeader, err := ts.tarR.Next()
if err != nil {
if err == io.EOF {
if err := ts.gz.Close(); err != nil {
return 0, err
}
ts.finished = true
return n, nil
}
return n, err
}
ts.currentFile = strings.TrimSuffix(strings.TrimPrefix(currentHeader.Name, "./"), "/")
if err := ts.encodeHeader(currentHeader); err != nil {
return 0, err
}
if err := ts.tarW.WriteHeader(currentHeader); err != nil {
return 0, err
}
if _, err := ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
if _, err := io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}
return n, err
}
// Filling the hash buffer
if _, err = ts.h.Write(buf2[:n]); err != nil {
return 0, err
}
// Filling the tar writter
if _, err = ts.tarW.Write(buf2[:n]); err != nil {
return 0, err
}
ts.tarW.Flush()
// Filling the gz writter
if _, err = io.Copy(ts.gz, ts.bufTar); err != nil {
return 0, err
}
ts.gz.Flush()
return ts.bufGz.Read(buf)
}