github.com/flavio/docker@v0.1.3-0.20170117145210-f63d1a6eec47/pkg/archive/archive_unix.go (about)

     1  // +build !windows
     2  
     3  package archive
     4  
     5  import (
     6  	"archive/tar"
     7  	"errors"
     8  	"os"
     9  	"path/filepath"
    10  	"syscall"
    11  
    12  	"github.com/docker/docker/pkg/system"
    13  	rsystem "github.com/opencontainers/runc/libcontainer/system"
    14  )
    15  
    16  // fixVolumePathPrefix does platform specific processing to ensure that if
    17  // the path being passed in is not in a volume path format, convert it to one.
    18  func fixVolumePathPrefix(srcPath string) string {
    19  	return srcPath
    20  }
    21  
    22  // getWalkRoot calculates the root path when performing a TarWithOptions.
    23  // We use a separate function as this is platform specific. On Linux, we
    24  // can't use filepath.Join(srcPath,include) because this will clean away
    25  // a trailing "." or "/" which may be important.
    26  func getWalkRoot(srcPath string, include string) string {
    27  	return srcPath + string(filepath.Separator) + include
    28  }
    29  
    30  // CanonicalTarNameForPath returns platform-specific filepath
    31  // to canonical posix-style path for tar archival. p is relative
    32  // path.
    33  func CanonicalTarNameForPath(p string) (string, error) {
    34  	return p, nil // already unix-style
    35  }
    36  
    37  // chmodTarEntry is used to adjust the file permissions used in tar header based
    38  // on the platform the archival is done.
    39  
    40  func chmodTarEntry(perm os.FileMode) os.FileMode {
    41  	return perm // noop for unix as golang APIs provide perm bits correctly
    42  }
    43  
    44  func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (inode uint64, err error) {
    45  	s, ok := stat.(*syscall.Stat_t)
    46  
    47  	if !ok {
    48  		err = errors.New("cannot convert stat value to syscall.Stat_t")
    49  		return
    50  	}
    51  
    52  	inode = uint64(s.Ino)
    53  
    54  	// Currently go does not fill in the major/minors
    55  	if s.Mode&syscall.S_IFBLK != 0 ||
    56  		s.Mode&syscall.S_IFCHR != 0 {
    57  		hdr.Devmajor = int64(major(uint64(s.Rdev)))
    58  		hdr.Devminor = int64(minor(uint64(s.Rdev)))
    59  	}
    60  
    61  	return
    62  }
    63  
    64  func getFileUIDGID(stat interface{}) (int, int, error) {
    65  	s, ok := stat.(*syscall.Stat_t)
    66  
    67  	if !ok {
    68  		return -1, -1, errors.New("cannot convert stat value to syscall.Stat_t")
    69  	}
    70  	return int(s.Uid), int(s.Gid), nil
    71  }
    72  
    73  func major(device uint64) uint64 {
    74  	return (device >> 8) & 0xfff
    75  }
    76  
    77  func minor(device uint64) uint64 {
    78  	return (device & 0xff) | ((device >> 12) & 0xfff00)
    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 |= syscall.S_IFBLK
    93  	case tar.TypeChar:
    94  		mode |= syscall.S_IFCHR
    95  	case tar.TypeFifo:
    96  		mode |= syscall.S_IFIFO
    97  	}
    98  
    99  	if err := system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor))); err != nil {
   100  		return err
   101  	}
   102  	return nil
   103  }
   104  
   105  func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
   106  	if hdr.Typeflag == tar.TypeLink {
   107  		if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
   108  			if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
   109  				return err
   110  			}
   111  		}
   112  	} else if hdr.Typeflag != tar.TypeSymlink {
   113  		if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
   114  			return err
   115  		}
   116  	}
   117  	return nil
   118  }