containerd/archive/tar_linux.go

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