github.com/demonoid81/moby@v0.0.0-20200517203328-62dd8e17c460/pkg/archive/archive_unix.go (about)

     1  // +build !windows
     2  
     3  package archive // import "github.com/demonoid81/moby/pkg/archive"
     4  
     5  import (
     6  	"archive/tar"
     7  	"errors"
     8  	"os"
     9  	"path/filepath"
    10  	"strings"
    11  	"syscall"
    12  
    13  	"github.com/demonoid81/moby/pkg/idtools"
    14  	"github.com/demonoid81/moby/pkg/system"
    15  	rsystem "github.com/opencontainers/runc/libcontainer/system"
    16  	"golang.org/x/sys/unix"
    17  )
    18  
    19  // fixVolumePathPrefix does platform specific processing to ensure that if
    20  // the path being passed in is not in a volume path format, convert it to one.
    21  func fixVolumePathPrefix(srcPath string) string {
    22  	return srcPath
    23  }
    24  
    25  // getWalkRoot calculates the root path when performing a TarWithOptions.
    26  // We use a separate function as this is platform specific. On Linux, we
    27  // can't use filepath.Join(srcPath,include) because this will clean away
    28  // a trailing "." or "/" which may be important.
    29  func getWalkRoot(srcPath string, include string) string {
    30  	return strings.TrimSuffix(srcPath, string(filepath.Separator)) + string(filepath.Separator) + include
    31  }
    32  
    33  // CanonicalTarNameForPath returns platform-specific filepath
    34  // to canonical posix-style path for tar archival. p is relative
    35  // path.
    36  func CanonicalTarNameForPath(p string) string {
    37  	return p // already unix-style
    38  }
    39  
    40  // chmodTarEntry is used to adjust the file permissions used in tar header based
    41  // on the platform the archival is done.
    42  
    43  func chmodTarEntry(perm os.FileMode) os.FileMode {
    44  	return perm // noop for unix as golang APIs provide perm bits correctly
    45  }
    46  
    47  func setHeaderForSpecialDevice(hdr *tar.Header, name string, stat interface{}) (err error) {
    48  	s, ok := stat.(*syscall.Stat_t)
    49  
    50  	if ok {
    51  		// Currently go does not fill in the major/minors
    52  		if s.Mode&unix.S_IFBLK != 0 ||
    53  			s.Mode&unix.S_IFCHR != 0 {
    54  			hdr.Devmajor = int64(unix.Major(uint64(s.Rdev))) // nolint: unconvert
    55  			hdr.Devminor = int64(unix.Minor(uint64(s.Rdev))) // nolint: unconvert
    56  		}
    57  	}
    58  
    59  	return
    60  }
    61  
    62  func getInodeFromStat(stat interface{}) (inode uint64, err error) {
    63  	s, ok := stat.(*syscall.Stat_t)
    64  
    65  	if ok {
    66  		inode = s.Ino
    67  	}
    68  
    69  	return
    70  }
    71  
    72  func getFileUIDGID(stat interface{}) (idtools.Identity, error) {
    73  	s, ok := stat.(*syscall.Stat_t)
    74  
    75  	if !ok {
    76  		return idtools.Identity{}, errors.New("cannot convert stat value to syscall.Stat_t")
    77  	}
    78  	return idtools.Identity{UID: int(s.Uid), GID: int(s.Gid)}, nil
    79  }
    80  
    81  // handleTarTypeBlockCharFifo is an OS-specific helper function used by
    82  // createTarFile to handle the following types of header: Block; Char; Fifo
    83  func handleTarTypeBlockCharFifo(hdr *tar.Header, path string) error {
    84  	if rsystem.RunningInUserNS() {
    85  		// cannot create a device if running in user namespace
    86  		return nil
    87  	}
    88  
    89  	mode := uint32(hdr.Mode & 07777)
    90  	switch hdr.Typeflag {
    91  	case tar.TypeBlock:
    92  		mode |= unix.S_IFBLK
    93  	case tar.TypeChar:
    94  		mode |= unix.S_IFCHR
    95  	case tar.TypeFifo:
    96  		mode |= unix.S_IFIFO
    97  	}
    98  
    99  	return system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor)))
   100  }
   101  
   102  func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
   103  	if hdr.Typeflag == tar.TypeLink {
   104  		if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
   105  			if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
   106  				return err
   107  			}
   108  		}
   109  	} else if hdr.Typeflag != tar.TypeSymlink {
   110  		if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
   111  			return err
   112  		}
   113  	}
   114  	return nil
   115  }