github.com/docker/docker@v299999999.0.0-20200612211812-aaf470eca7b5+incompatible/container/archive.go (about)

     1  package container // import "github.com/docker/docker/container"
     2  
     3  import (
     4  	"os"
     5  
     6  	"github.com/docker/docker/api/types"
     7  	"github.com/docker/docker/pkg/archive"
     8  	"github.com/docker/docker/pkg/system"
     9  	"github.com/pkg/errors"
    10  )
    11  
    12  // ResolvePath resolves the given path in the container to a resource on the
    13  // host. Returns a resolved path (absolute path to the resource on the host),
    14  // the absolute path to the resource relative to the container's rootfs, and
    15  // an error if the path points to outside the container's rootfs.
    16  func (container *Container) ResolvePath(path string) (resolvedPath, absPath string, err error) {
    17  	if container.BaseFS == nil {
    18  		return "", "", errors.New("ResolvePath: BaseFS of container " + container.ID + " is unexpectedly nil")
    19  	}
    20  	// Check if a drive letter supplied, it must be the system drive. No-op except on Windows
    21  	path, err = system.CheckSystemDriveAndRemoveDriveLetter(path, container.BaseFS)
    22  	if err != nil {
    23  		return "", "", err
    24  	}
    25  
    26  	// Consider the given path as an absolute path in the container.
    27  	absPath = archive.PreserveTrailingDotOrSeparator(
    28  		container.BaseFS.Join(string(container.BaseFS.Separator()), path),
    29  		path,
    30  		container.BaseFS.Separator())
    31  
    32  	// Split the absPath into its Directory and Base components. We will
    33  	// resolve the dir in the scope of the container then append the base.
    34  	dirPath, basePath := container.BaseFS.Split(absPath)
    35  
    36  	resolvedDirPath, err := container.GetResourcePath(dirPath)
    37  	if err != nil {
    38  		return "", "", err
    39  	}
    40  
    41  	// resolvedDirPath will have been cleaned (no trailing path separators) so
    42  	// we can manually join it with the base path element.
    43  	resolvedPath = resolvedDirPath + string(container.BaseFS.Separator()) + basePath
    44  	return resolvedPath, absPath, nil
    45  }
    46  
    47  // StatPath is the unexported version of StatPath. Locks and mounts should
    48  // be acquired before calling this method and the given path should be fully
    49  // resolved to a path on the host corresponding to the given absolute path
    50  // inside the container.
    51  func (container *Container) StatPath(resolvedPath, absPath string) (stat *types.ContainerPathStat, err error) {
    52  	if container.BaseFS == nil {
    53  		return nil, errors.New("StatPath: BaseFS of container " + container.ID + " is unexpectedly nil")
    54  	}
    55  	driver := container.BaseFS
    56  
    57  	lstat, err := driver.Lstat(resolvedPath)
    58  	if err != nil {
    59  		return nil, err
    60  	}
    61  
    62  	var linkTarget string
    63  	if lstat.Mode()&os.ModeSymlink != 0 {
    64  		// Fully evaluate the symlink in the scope of the container rootfs.
    65  		hostPath, err := container.GetResourcePath(absPath)
    66  		if err != nil {
    67  			return nil, err
    68  		}
    69  
    70  		linkTarget, err = driver.Rel(driver.Path(), hostPath)
    71  		if err != nil {
    72  			return nil, err
    73  		}
    74  
    75  		// Make it an absolute path.
    76  		linkTarget = driver.Join(string(driver.Separator()), linkTarget)
    77  	}
    78  
    79  	return &types.ContainerPathStat{
    80  		Name:       driver.Base(absPath),
    81  		Size:       lstat.Size(),
    82  		Mode:       lstat.Mode(),
    83  		Mtime:      lstat.ModTime(),
    84  		LinkTarget: linkTarget,
    85  	}, nil
    86  }