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moby--moby/daemon/archive.go
Josh Hawn c32dde5baa daemon: container ArchivePath and ExtractToDir
The following methods will deprecate the Copy method and introduce
two new, well-behaved methods for creating a tar archive of a resource
in a container and for extracting a tar archive into a directory in a
container.

Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
2015-07-21 11:20:10 -07:00

297 lines
8.9 KiB
Go

package daemon
import (
"errors"
"io"
"os"
"path/filepath"
"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 depracated 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 = res[1:]
}
return container.Copy(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 container.StatPath(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 container.ArchivePath(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 container.ExtractToDir(path, noOverwriteDirNonDir, content)
}
// StatPath stats the filesystem resource at the specified path in this
// container. Returns stat info about the resource.
func (container *Container) StatPath(path string) (stat *types.ContainerPathStat, err error) {
container.Lock()
defer container.Unlock()
if err = container.Mount(); err != nil {
return nil, err
}
defer container.Unmount()
err = container.mountVolumes()
defer container.UnmountVolumes(true)
if err != nil {
return nil, err
}
// Consider the given path as an absolute path in the container.
absPath := path
if !filepath.IsAbs(absPath) {
absPath = archive.PreserveTrailingDotOrSeparator(filepath.Join("/", path), path)
}
resolvedPath, err := container.GetResourcePath(absPath)
if err != nil {
return nil, err
}
// A trailing "." or separator has important meaning. For example, if
// `"foo"` is a symlink to some directory `"dir"`, then `os.Lstat("foo")`
// will stat the link itself, while `os.Lstat("foo/")` will stat the link
// target. If the basename of the path is ".", it means to archive the
// contents of the directory with "." as the first path component rather
// than the name of the directory. This would cause extraction of the
// archive to *not* make another directory, but instead use the current
// directory.
resolvedPath = archive.PreserveTrailingDotOrSeparator(resolvedPath, absPath)
lstat, err := os.Lstat(resolvedPath)
if err != nil {
return nil, err
}
return &types.ContainerPathStat{
Name: lstat.Name(),
Path: absPath,
Size: lstat.Size(),
Mode: lstat.Mode(),
Mtime: lstat.ModTime(),
}, nil
}
// ArchivePath 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 (container *Container) ArchivePath(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 = container.Mount(); err != nil {
return nil, nil, err
}
defer func() {
if err != nil {
// unmount any volumes
container.UnmountVolumes(true)
// unmount the container's rootfs
container.Unmount()
}
}()
if err = container.mountVolumes(); err != nil {
return nil, nil, err
}
// Consider the given path as an absolute path in the container.
absPath := path
if !filepath.IsAbs(absPath) {
absPath = archive.PreserveTrailingDotOrSeparator(filepath.Join("/", path), path)
}
resolvedPath, err := container.GetResourcePath(absPath)
if err != nil {
return nil, nil, err
}
// A trailing "." or separator has important meaning. For example, if
// `"foo"` is a symlink to some directory `"dir"`, then `os.Lstat("foo")`
// will stat the link itself, while `os.Lstat("foo/")` will stat the link
// target. If the basename of the path is ".", it means to archive the
// contents of the directory with "." as the first path component rather
// than the name of the directory. This would cause extraction of the
// archive to *not* make another directory, but instead use the current
// directory.
resolvedPath = archive.PreserveTrailingDotOrSeparator(resolvedPath, absPath)
lstat, err := os.Lstat(resolvedPath)
if err != nil {
return nil, nil, err
}
stat = &types.ContainerPathStat{
Name: lstat.Name(),
Path: absPath,
Size: lstat.Size(),
Mode: lstat.Mode(),
Mtime: lstat.ModTime(),
}
data, err := archive.TarResource(resolvedPath)
if err != nil {
return nil, nil, err
}
content = ioutils.NewReadCloserWrapper(data, func() error {
err := data.Close()
container.UnmountVolumes(true)
container.Unmount()
container.Unlock()
return err
})
container.LogEvent("archive-path")
return content, stat, nil
}
// ExtractToDir 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 (container *Container) ExtractToDir(path string, noOverwriteDirNonDir bool, content io.Reader) (err error) {
container.Lock()
defer container.Unlock()
if err = container.Mount(); err != nil {
return err
}
defer container.Unmount()
err = container.mountVolumes()
defer container.UnmountVolumes(true)
if err != nil {
return err
}
// Consider the given path as an absolute path in the container.
absPath := path
if !filepath.IsAbs(absPath) {
absPath = archive.PreserveTrailingDotOrSeparator(filepath.Join("/", path), path)
}
resolvedPath, err := container.GetResourcePath(absPath)
if err != nil {
return err
}
// A trailing "." or separator has important meaning. For example, if
// `"foo"` is a symlink to some directory `"dir"`, then `os.Lstat("foo")`
// will stat the link itself, while `os.Lstat("foo/")` will stat the link
// target. If the basename of the path is ".", it means to archive the
// contents of the directory with "." as the first path component rather
// than the name of the directory. This would cause extraction of the
// archive to *not* make another directory, but instead use the current
// directory.
resolvedPath = archive.PreserveTrailingDotOrSeparator(resolvedPath, absPath)
stat, err := os.Lstat(resolvedPath)
if err != nil {
return err
}
if !stat.IsDir() {
return ErrExtractPointNotDirectory
}
baseRel, err := filepath.Rel(container.basefs, resolvedPath)
if err != nil {
return err
}
absPath = filepath.Join("/", baseRel)
// 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.
var toVolume bool
for _, mnt := range container.MountPoints {
if toVolume = mnt.hasResource(absPath); toVolume {
if mnt.RW {
break
}
return ErrVolumeReadonly
}
}
if !toVolume && container.hostConfig.ReadonlyRootfs {
return ErrContainerRootfsReadonly
}
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
}
container.LogEvent("extract-to-dir")
return nil
}