0deba01621
Archive package handles generating and applying diff tar streams based on the OCI diff tar specification. Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
134 lines
2.9 KiB
Go
134 lines
2.9 KiB
Go
package archive
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import (
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"archive/tar"
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"os"
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"sync"
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"syscall"
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"github.com/opencontainers/runc/libcontainer/system"
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"github.com/pkg/errors"
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"github.com/stevvooe/continuity/sysx"
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)
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func tarName(p string) (string, error) {
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return p, nil
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}
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func chmodTarEntry(perm os.FileMode) os.FileMode {
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return perm
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}
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func setHeaderForSpecialDevice(hdr *tar.Header, name string, fi os.FileInfo) error {
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s, ok := fi.Sys().(*syscall.Stat_t)
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if !ok {
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return errors.New("unsupported stat type")
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}
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// Currently go does not fill in the major/minors
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if s.Mode&syscall.S_IFBLK != 0 ||
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s.Mode&syscall.S_IFCHR != 0 {
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hdr.Devmajor = int64(major(uint64(s.Rdev)))
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hdr.Devminor = int64(minor(uint64(s.Rdev)))
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}
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return nil
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}
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func major(device uint64) uint64 {
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return (device >> 8) & 0xfff
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}
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func minor(device uint64) uint64 {
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return (device & 0xff) | ((device >> 12) & 0xfff00)
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}
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func mkdev(major int64, minor int64) uint32 {
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return uint32(((minor & 0xfff00) << 12) | ((major & 0xfff) << 8) | (minor & 0xff))
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}
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func open(p string) (*os.File, error) {
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return os.Open(p)
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}
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func openFile(name string, flag int, perm os.FileMode) (*os.File, error) {
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return os.OpenFile(name, flag, perm)
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}
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func mkdirAll(path string, perm os.FileMode) error {
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return os.MkdirAll(path, perm)
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}
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func prepareApply() func() {
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// Unset unmask before doing an apply operation,
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// restore unmask when complete
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oldmask := syscall.Umask(0)
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return func() {
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syscall.Umask(oldmask)
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}
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}
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func skipFile(*tar.Header) bool {
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return false
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}
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var (
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inUserNS bool
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nsOnce sync.Once
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)
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func setInUserNS() {
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inUserNS = system.RunningInUserNS()
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}
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// handleTarTypeBlockCharFifo is an OS-specific helper function used by
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// createTarFile to handle the following types of header: Block; Char; Fifo
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func handleTarTypeBlockCharFifo(hdr *tar.Header, path string) error {
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nsOnce.Do(setInUserNS)
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if inUserNS {
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// cannot create a device if running in user namespace
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return nil
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}
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mode := uint32(hdr.Mode & 07777)
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switch hdr.Typeflag {
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case tar.TypeBlock:
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mode |= syscall.S_IFBLK
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case tar.TypeChar:
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mode |= syscall.S_IFCHR
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case tar.TypeFifo:
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mode |= syscall.S_IFIFO
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}
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if err := syscall.Mknod(path, mode, int(mkdev(hdr.Devmajor, hdr.Devminor))); err != nil {
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return err
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}
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return nil
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}
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func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
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if hdr.Typeflag == tar.TypeLink {
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if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
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if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
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return err
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}
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}
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} else if hdr.Typeflag != tar.TypeSymlink {
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if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
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return err
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}
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}
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return nil
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}
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func getxattr(path, attr string) ([]byte, error) {
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b, err := sysx.LGetxattr(path, attr)
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if err == syscall.ENOTSUP || err == syscall.ENODATA {
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return nil, nil
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}
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return b, err
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}
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func setxattr(path, key, value string) error {
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return sysx.LSetxattr(path, key, []byte(value), 0)
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}
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