// 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)
}
func addTarFile(path, name string, tw *tar.Writer, twBuf *bufio.Writer) error {
fi, err := os.Lstat(path)
if err != nil {
return err
}
link := ""
if fi.Mode()&os.ModeSymlink != 0 {
if link, err = os.Readlink(path); err != nil {
return err
}
}
hdr, err := tar.FileInfoHeader(fi, link)
if err != nil {
return err
}
if fi.IsDir() && !strings.HasSuffix(name, "/") {
name = name + "/"
}
hdr.Name = name
stat, ok := fi.Sys().(*syscall.Stat_t)
if ok {
// Currently go does not fill in the major/minors
if stat.Mode&syscall.S_IFBLK == syscall.S_IFBLK ||
stat.Mode&syscall.S_IFCHR == syscall.S_IFCHR {
hdr.Devmajor = int64(major(uint64(stat.Rdev)))
hdr.Devminor = int64(minor(uint64(stat.Rdev)))
}
}
capability, _ := system.Lgetxattr(path, "security.capability")
if capability != nil {
hdr.Xattrs = make(map[string]string)
hdr.Xattrs["security.capability"] = string(capability)
}
if err := tw.WriteHeader(hdr); err != nil {
return err
}
if hdr.Typeflag == tar.TypeReg {
file, err := os.Open(path)
if err != nil {
return err
}
twBuf.Reset(tw)
_, err = io.Copy(twBuf, file)
file.Close()
if err != nil {
return err
}
err = twBuf.Flush()
if err != nil {
return err
}
twBuf.Reset(nil)
}
return nil
}