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moby--moby/pkg/archive/archive_unix.go
Serge Hallyn 617c352e92 Don't create devices if in a user namespace
If we are running in a user namespace, don't try to mknod as
it won't be allowed.  libcontainer will bind-mount the host's
devices over files in the container anyway, so it's not needed.

The chrootarchive package does a chroot (without mounting /proc) before
its work, so we cannot check /proc/self/uid_map when we need to.  So
compute it in advance and pass it along with the tar options.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
2016-08-12 16:26:58 -04:00

118 lines
3.2 KiB
Go

// +build !windows
package archive
import (
"archive/tar"
"errors"
"os"
"path/filepath"
"syscall"
"github.com/docker/docker/pkg/system"
rsystem "github.com/opencontainers/runc/libcontainer/system"
)
// fixVolumePathPrefix does platform specific processing to ensure that if
// the path being passed in is not in a volume path format, convert it to one.
func fixVolumePathPrefix(srcPath string) string {
return srcPath
}
// getWalkRoot calculates the root path when performing a TarWithOptions.
// We use a separate function as this is platform specific. On Linux, we
// can't use filepath.Join(srcPath,include) because this will clean away
// a trailing "." or "/" which may be important.
func getWalkRoot(srcPath string, include string) string {
return srcPath + string(filepath.Separator) + include
}
// CanonicalTarNameForPath returns platform-specific filepath
// to canonical posix-style path for tar archival. p is relative
// path.
func CanonicalTarNameForPath(p string) (string, error) {
return p, nil // already unix-style
}
// chmodTarEntry is used to adjust the file permissions used in tar header based
// on the platform the archival is done.
func chmodTarEntry(perm os.FileMode) os.FileMode {
return perm // noop for unix as golang APIs provide perm bits correctly
}
func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (inode uint64, err error) {
s, ok := stat.(*syscall.Stat_t)
if !ok {
err = errors.New("cannot convert stat value to syscall.Stat_t")
return
}
inode = uint64(s.Ino)
// 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
}
func getFileUIDGID(stat interface{}) (int, int, error) {
s, ok := stat.(*syscall.Stat_t)
if !ok {
return -1, -1, errors.New("cannot convert stat value to syscall.Stat_t")
}
return int(s.Uid), int(s.Gid), nil
}
func major(device uint64) uint64 {
return (device >> 8) & 0xfff
}
func minor(device uint64) uint64 {
return (device & 0xff) | ((device >> 12) & 0xfff00)
}
// 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 {
if rsystem.RunningInUserNS() {
// 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
}
if err := system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor))); err != nil {
return err
}
return nil
}
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
}