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moby--moby/daemon/archive.go

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package daemon
import (
"errors"
"io"
"os"
"path/filepath"
"strings"
"github.com/docker/docker/api/types"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/ioutils"
)
// ErrExtractPointNotDirectory is used to convey that the operation to extract
// a tar archive to a directory in a container has failed because the specified
// path does not refer to a directory.
var ErrExtractPointNotDirectory = errors.New("extraction point is not a directory")
// ContainerCopy performs a deprecated operation of archiving the resource at
// the specified path in the conatiner identified by the given name.
func (daemon *Daemon) ContainerCopy(name string, res string) (io.ReadCloser, error) {
container, err := daemon.Get(name)
if err != nil {
return nil, err
}
if res[0] == '/' || res[0] == '\\' {
res = res[1:]
}
return daemon.containerCopy(container, res)
}
// ContainerStatPath stats the filesystem resource at the specified path in the
// container identified by the given name.
func (daemon *Daemon) ContainerStatPath(name string, path string) (stat *types.ContainerPathStat, err error) {
container, err := daemon.Get(name)
if err != nil {
return nil, err
}
return daemon.containerStatPath(container, path)
}
// ContainerArchivePath creates an archive of the filesystem resource at the
// specified path in the container identified by the given name. Returns a
// tar archive of the resource and whether it was a directory or a single file.
func (daemon *Daemon) ContainerArchivePath(name string, path string) (content io.ReadCloser, stat *types.ContainerPathStat, err error) {
container, err := daemon.Get(name)
if err != nil {
return nil, nil, err
}
return daemon.containerArchivePath(container, path)
}
// ContainerExtractToDir extracts the given archive to the specified location
// in the filesystem of the container identified by the given name. The given
// path must be of a directory in the container. If it is not, the error will
// be ErrExtractPointNotDirectory. If noOverwriteDirNonDir is true then it will
// be an error if unpacking the given content would cause an existing directory
// to be replaced with a non-directory and vice versa.
func (daemon *Daemon) ContainerExtractToDir(name, path string, noOverwriteDirNonDir bool, content io.Reader) error {
container, err := daemon.Get(name)
if err != nil {
return err
}
return daemon.containerExtractToDir(container, path, noOverwriteDirNonDir, content)
}
// resolvePath resolves the given path in the container to a resource on the
// host. Returns a resolved path (absolute path to the resource on the host),
// the absolute path to the resource relative to the container's rootfs, and
// a error if the path points to outside the container's rootfs.
func (container *Container) resolvePath(path string) (resolvedPath, absPath string, err error) {
// Consider the given path as an absolute path in the container.
absPath = archive.PreserveTrailingDotOrSeparator(filepath.Join(string(filepath.Separator), path), path)
// Split the absPath into its Directory and Base components. We will
// resolve the dir in the scope of the container then append the base.
dirPath, basePath := filepath.Split(absPath)
resolvedDirPath, err := container.GetResourcePath(dirPath)
if err != nil {
return "", "", err
}
// resolvedDirPath will have been cleaned (no trailing path separators) so
// we can manually join it with the base path element.
resolvedPath = resolvedDirPath + string(filepath.Separator) + basePath
return resolvedPath, absPath, nil
}
// statPath is the unexported version of StatPath. Locks and mounts should
// be acquired before calling this method and the given path should be fully
// resolved to a path on the host corresponding to the given absolute path
// inside the container.
func (container *Container) statPath(resolvedPath, absPath string) (stat *types.ContainerPathStat, err error) {
lstat, err := os.Lstat(resolvedPath)
if err != nil {
return nil, err
}
var linkTarget string
if lstat.Mode()&os.ModeSymlink != 0 {
// Fully evaluate the symlink in the scope of the container rootfs.
hostPath, err := container.GetResourcePath(absPath)
if err != nil {
return nil, err
}
linkTarget, err = filepath.Rel(container.basefs, hostPath)
if err != nil {
return nil, err
}
// Make it an absolute path.
linkTarget = filepath.Join(string(filepath.Separator), linkTarget)
}
return &types.ContainerPathStat{
Name: filepath.Base(absPath),
Size: lstat.Size(),
Mode: lstat.Mode(),
Mtime: lstat.ModTime(),
LinkTarget: linkTarget,
}, nil
}
// containerStatPath stats the filesystem resource at the specified path in this
// container. Returns stat info about the resource.
func (daemon *Daemon) containerStatPath(container *Container, path string) (stat *types.ContainerPathStat, err error) {
container.Lock()
defer container.Unlock()
if err = daemon.Mount(container); err != nil {
return nil, err
}
defer daemon.Unmount(container)
err = daemon.mountVolumes(container)
defer container.unmountVolumes(true)
if err != nil {
return nil, err
}
resolvedPath, absPath, err := container.resolvePath(path)
if err != nil {
return nil, err
}
return container.statPath(resolvedPath, absPath)
}
// containerArchivePath creates an archive of the filesystem resource at the specified
// path in this container. Returns a tar archive of the resource and stat info
// about the resource.
func (daemon *Daemon) containerArchivePath(container *Container, path string) (content io.ReadCloser, stat *types.ContainerPathStat, err error) {
container.Lock()
defer func() {
if err != nil {
// Wait to unlock the container until the archive is fully read
// (see the ReadCloseWrapper func below) or if there is an error
// before that occurs.
container.Unlock()
}
}()
if err = daemon.Mount(container); err != nil {
return nil, nil, err
}
defer func() {
if err != nil {
// unmount any volumes
container.unmountVolumes(true)
// unmount the container's rootfs
daemon.Unmount(container)
}
}()
if err = daemon.mountVolumes(container); err != nil {
return nil, nil, err
}
resolvedPath, absPath, err := container.resolvePath(path)
if err != nil {
return nil, nil, err
}
stat, err = container.statPath(resolvedPath, absPath)
if err != nil {
return nil, nil, err
}
// We need to rebase the archive entries if the last element of the
// resolved path was a symlink that was evaluated and is now different
// than the requested path. For example, if the given path was "/foo/bar/",
// but it resolved to "/var/lib/docker/containers/{id}/foo/baz/", we want
// to ensure that the archive entries start with "bar" and not "baz". This
// also catches the case when the root directory of the container is
// requested: we want the archive entries to start with "/" and not the
// container ID.
data, err := archive.TarResourceRebase(resolvedPath, filepath.Base(absPath))
if err != nil {
return nil, nil, err
}
content = ioutils.NewReadCloserWrapper(data, func() error {
err := data.Close()
container.unmountVolumes(true)
daemon.Unmount(container)
container.Unlock()
return err
})
daemon.LogContainerEvent(container, "archive-path")
return content, stat, nil
}
// containerExtractToDir extracts the given tar archive to the specified location in the
// filesystem of this container. The given path must be of a directory in the
// container. If it is not, the error will be ErrExtractPointNotDirectory. If
// noOverwriteDirNonDir is true then it will be an error if unpacking the
// given content would cause an existing directory to be replaced with a non-
// directory and vice versa.
func (daemon *Daemon) containerExtractToDir(container *Container, path string, noOverwriteDirNonDir bool, content io.Reader) (err error) {
container.Lock()
defer container.Unlock()
if err = daemon.Mount(container); err != nil {
return err
}
defer daemon.Unmount(container)
err = daemon.mountVolumes(container)
defer container.unmountVolumes(true)
if err != nil {
return err
}
// The destination path needs to be resolved to a host path, with all
// symbolic links followed in the scope of the container's rootfs. Note
// that we do not use `container.resolvePath(path)` here because we need
// to also evaluate the last path element if it is a symlink. This is so
// that you can extract an archive to a symlink that points to a directory.
// Consider the given path as an absolute path in the container.
absPath := archive.PreserveTrailingDotOrSeparator(filepath.Join(string(filepath.Separator), path), path)
// This will evaluate the last path element if it is a symlink.
resolvedPath, err := container.GetResourcePath(absPath)
if err != nil {
return err
}
stat, err := os.Lstat(resolvedPath)
if err != nil {
return err
}
if !stat.IsDir() {
return ErrExtractPointNotDirectory
}
// Need to check if the path is in a volume. If it is, it cannot be in a
// read-only volume. If it is not in a volume, the container cannot be
// configured with a read-only rootfs.
// Use the resolved path relative to the container rootfs as the new
// absPath. This way we fully follow any symlinks in a volume that may
// lead back outside the volume.
//
// The Windows implementation of filepath.Rel in golang 1.4 does not
// support volume style file path semantics. On Windows when using the
// filter driver, we are guaranteed that the path will always be
// a volume file path.
var baseRel string
if strings.HasPrefix(resolvedPath, `\\?\Volume{`) {
if strings.HasPrefix(resolvedPath, container.basefs) {
baseRel = resolvedPath[len(container.basefs):]
if baseRel[:1] == `\` {
baseRel = baseRel[1:]
}
}
} else {
baseRel, err = filepath.Rel(container.basefs, resolvedPath)
}
if err != nil {
return err
}
// Make it an absolute path.
absPath = filepath.Join(string(filepath.Separator), baseRel)
toVolume, err := checkIfPathIsInAVolume(container, absPath)
if err != nil {
return err
}
if !toVolume && container.hostConfig.ReadonlyRootfs {
return ErrRootFSReadOnly
}
options := &archive.TarOptions{
ChownOpts: &archive.TarChownOptions{
UID: 0, GID: 0, // TODO: use config.User? Remap to userns root?
},
NoOverwriteDirNonDir: noOverwriteDirNonDir,
}
if err := chrootarchive.Untar(content, resolvedPath, options); err != nil {
return err
}
daemon.LogContainerEvent(container, "extract-to-dir")
return nil
}
func (daemon *Daemon) containerCopy(container *Container, resource string) (rc io.ReadCloser, err error) {
container.Lock()
defer func() {
if err != nil {
// Wait to unlock the container until the archive is fully read
// (see the ReadCloseWrapper func below) or if there is an error
// before that occurs.
container.Unlock()
}
}()
if err := daemon.Mount(container); err != nil {
return nil, err
}
defer func() {
if err != nil {
// unmount any volumes
container.unmountVolumes(true)
// unmount the container's rootfs
daemon.Unmount(container)
}
}()
if err := daemon.mountVolumes(container); err != nil {
return nil, err
}
basePath, err := container.GetResourcePath(resource)
if err != nil {
return nil, err
}
stat, err := os.Stat(basePath)
if err != nil {
return nil, err
}
var filter []string
if !stat.IsDir() {
d, f := filepath.Split(basePath)
basePath = d
filter = []string{f}
} else {
filter = []string{filepath.Base(basePath)}
basePath = filepath.Dir(basePath)
}
archive, err := archive.TarWithOptions(basePath, &archive.TarOptions{
Compression: archive.Uncompressed,
IncludeFiles: filter,
})
if err != nil {
return nil, err
}
reader := ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
container.unmountVolumes(true)
daemon.Unmount(container)
container.Unlock()
return err
})
daemon.LogContainerEvent(container, "copy")
return reader, nil
}