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authorValentin Rothberg <rothberg@redhat.com>2021-03-02 09:20:53 +0100
committerValentin Rothberg <rothberg@redhat.com>2021-03-04 15:43:12 +0100
commita090301bbb10424ce4f99e40c97959f0e8664718 (patch)
tree3b2596e3d152204d35162b1ca89f524c5803ad8c /libpod
parent833670079c5b1f95fbb7c9bb8ba9095f1c66c7b4 (diff)
downloadpodman-a090301bbb10424ce4f99e40c97959f0e8664718.tar.gz
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podman cp: support copying on tmpfs mounts
Traditionally, the path resolution for containers has been resolved on the *host*; relative to the container's mount point or relative to specified bind mounts or volumes. While this works nicely for non-running containers, it poses a problem for running ones. In that case, certain kinds of mounts (e.g., tmpfs) will not resolve correctly. A tmpfs is held in memory and hence cannot be resolved relatively to the container's mount point. A copy operation will succeed but the data will not show up inside the container. To support these kinds of mounts, we need to join the *running* container's mount namespace (and PID namespace) when copying. Note that this change implies moving the copy and stat logic into `libpod` since we need to keep the container locked to avoid race conditions. The immediate benefit is that all logic is now inside `libpod`; the code isn't scattered anymore. Further note that Docker does not support copying to tmpfs mounts. Tests have been extended to cover *both* path resolutions for running and created containers. New tests have been added to exercise the tmpfs-mount case. For the record: Some tests could be improved by using `start -a` instead of a start-exec sequence. Unfortunately, `start -a` is flaky in the CI which forced me to use the more expensive start-exec option. Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Diffstat (limited to 'libpod')
-rw-r--r--libpod/container.go6
-rw-r--r--libpod/container_api.go64
-rw-r--r--libpod/container_copy_linux.go266
-rw-r--r--libpod/container_copy_unsupported.go16
-rw-r--r--libpod/container_internal.go4
-rw-r--r--libpod/container_path_resolution.go23
-rw-r--r--libpod/container_stat_linux.go157
-rw-r--r--libpod/container_stat_unsupported.go13
-rw-r--r--libpod/define/fileinfo.go16
9 files changed, 537 insertions, 28 deletions
diff --git a/libpod/container.go b/libpod/container.go
index ee6e243ac..65abbfd5e 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -904,6 +904,12 @@ func (c *Container) NamespacePath(linuxNS LinuxNS) (string, error) { //nolint:in
}
}
+ return c.namespacePath(linuxNS)
+}
+
+// namespacePath returns the path of one of the container's namespaces
+// If the container is not running, an error will be returned
+func (c *Container) namespacePath(linuxNS LinuxNS) (string, error) { //nolint:interfacer
if c.state.State != define.ContainerStateRunning && c.state.State != define.ContainerStatePaused {
return "", errors.Wrapf(define.ErrCtrStopped, "cannot get namespace path unless container %s is running", c.ID())
}
diff --git a/libpod/container_api.go b/libpod/container_api.go
index 2818ac841..6fa8b27cd 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -2,6 +2,7 @@ package libpod
import (
"context"
+ "io"
"io/ioutil"
"net/http"
"os"
@@ -349,10 +350,6 @@ func (c *Container) Mount() (string, error) {
}
}
- if c.state.State == define.ContainerStateRemoving {
- return "", errors.Wrapf(define.ErrCtrStateInvalid, "cannot mount container %s as it is being removed", c.ID())
- }
-
defer c.newContainerEvent(events.Mount)
return c.mount()
}
@@ -367,7 +364,6 @@ func (c *Container) Unmount(force bool) error {
return err
}
}
-
if c.state.Mounted {
mounted, err := c.runtime.storageService.MountedContainerImage(c.ID())
if err != nil {
@@ -847,31 +843,59 @@ func (c *Container) ShouldRestart(ctx context.Context) bool {
return c.shouldRestart()
}
-// ResolvePath resolves the specified path on the root for the container. The
-// root must either be the mounted image of the container or the already
-// mounted container storage.
-//
-// It returns the resolved root and the resolved path. Note that the path may
-// resolve to the container's mount point or to a volume or bind mount.
-func (c *Container) ResolvePath(ctx context.Context, root string, path string) (string, string, error) {
- logrus.Debugf("Resolving path %q (root %q) on container %s", path, root, c.ID())
+// CopyFromArchive copies the contents from the specified tarStream to path
+// *inside* the container.
+func (c *Container) CopyFromArchive(ctx context.Context, containerPath string, tarStream io.Reader) (func() error, error) {
+ if !c.batched {
+ c.lock.Lock()
+ defer c.lock.Unlock()
- // Minimal sanity checks.
- if len(root)*len(path) == 0 {
- return "", "", errors.Wrapf(define.ErrInternal, "ResolvePath: root (%q) and path (%q) must be non empty", root, path)
+ if err := c.syncContainer(); err != nil {
+ return nil, err
+ }
}
- if _, err := os.Stat(root); err != nil {
- return "", "", errors.Wrapf(err, "cannot locate root to resolve path on container %s", c.ID())
+
+ return c.copyFromArchive(ctx, containerPath, tarStream)
+}
+
+// CopyToArchive copies the contents from the specified path *inside* the
+// container to the tarStream.
+func (c *Container) CopyToArchive(ctx context.Context, containerPath string, tarStream io.Writer) (func() error, error) {
+ if !c.batched {
+ c.lock.Lock()
+ defer c.lock.Unlock()
+
+ if err := c.syncContainer(); err != nil {
+ return nil, err
+ }
}
+ return c.copyToArchive(ctx, containerPath, tarStream)
+}
+
+// Stat the specified path *inside* the container and return a file info.
+func (c *Container) Stat(ctx context.Context, containerPath string) (*define.FileInfo, error) {
if !c.batched {
c.lock.Lock()
defer c.lock.Unlock()
if err := c.syncContainer(); err != nil {
- return "", "", err
+ return nil, err
+ }
+ }
+
+ var mountPoint string
+ var err error
+ if c.state.Mounted {
+ mountPoint = c.state.Mountpoint
+ } else {
+ mountPoint, err = c.mount()
+ if err != nil {
+ return nil, err
}
+ defer c.unmount(false)
}
- return c.resolvePath(root, path)
+ info, _, _, err := c.stat(ctx, mountPoint, containerPath)
+ return info, err
}
diff --git a/libpod/container_copy_linux.go b/libpod/container_copy_linux.go
new file mode 100644
index 000000000..66ccd2f1f
--- /dev/null
+++ b/libpod/container_copy_linux.go
@@ -0,0 +1,266 @@
+// +build linux
+
+package libpod
+
+import (
+ "context"
+ "io"
+ "os"
+ "path/filepath"
+ "runtime"
+ "strings"
+
+ buildahCopiah "github.com/containers/buildah/copier"
+ "github.com/containers/buildah/pkg/chrootuser"
+ "github.com/containers/buildah/util"
+ "github.com/containers/podman/v3/libpod/define"
+ "github.com/containers/storage"
+ "github.com/containers/storage/pkg/idtools"
+ "github.com/docker/docker/pkg/archive"
+ "github.com/opencontainers/runtime-spec/specs-go"
+ "github.com/pkg/errors"
+ "github.com/sirupsen/logrus"
+ "golang.org/x/sys/unix"
+)
+
+func (c *Container) copyFromArchive(ctx context.Context, path string, reader io.Reader) (func() error, error) {
+ var (
+ mountPoint string
+ resolvedRoot string
+ resolvedPath string
+ unmount func()
+ err error
+ )
+
+ // Make sure that "/" copies the *contents* of the mount point and not
+ // the directory.
+ if path == "/" {
+ path = "/."
+ }
+
+ // Optimization: only mount if the container is not already.
+ if c.state.Mounted {
+ mountPoint = c.state.Mountpoint
+ unmount = func() {}
+ } else {
+ // NOTE: make sure to unmount in error paths.
+ mountPoint, err = c.mount()
+ if err != nil {
+ return nil, err
+ }
+ unmount = func() { c.unmount(false) }
+ }
+
+ if c.state.State == define.ContainerStateRunning {
+ resolvedRoot = "/"
+ resolvedPath = c.pathAbs(path)
+ } else {
+ resolvedRoot, resolvedPath, err = c.resolvePath(mountPoint, path)
+ if err != nil {
+ unmount()
+ return nil, err
+ }
+ }
+
+ decompressed, err := archive.DecompressStream(reader)
+ if err != nil {
+ unmount()
+ return nil, err
+ }
+
+ idMappings, idPair, err := getIDMappingsAndPair(c, mountPoint)
+ if err != nil {
+ decompressed.Close()
+ unmount()
+ return nil, err
+ }
+
+ logrus.Debugf("Container copy *to* %q (resolved: %q) on container %q (ID: %s)", path, resolvedPath, c.Name(), c.ID())
+
+ return func() error {
+ defer unmount()
+ defer decompressed.Close()
+ putOptions := buildahCopiah.PutOptions{
+ UIDMap: idMappings.UIDMap,
+ GIDMap: idMappings.GIDMap,
+ ChownDirs: idPair,
+ ChownFiles: idPair,
+ }
+
+ return c.joinMountAndExec(ctx,
+ func() error {
+ return buildahCopiah.Put(resolvedRoot, resolvedPath, putOptions, decompressed)
+ },
+ )
+ }, nil
+}
+
+func (c *Container) copyToArchive(ctx context.Context, path string, writer io.Writer) (func() error, error) {
+ var (
+ mountPoint string
+ unmount func()
+ err error
+ )
+
+ // Optimization: only mount if the container is not already.
+ if c.state.Mounted {
+ mountPoint = c.state.Mountpoint
+ unmount = func() {}
+ } else {
+ // NOTE: make sure to unmount in error paths.
+ mountPoint, err = c.mount()
+ if err != nil {
+ return nil, err
+ }
+ unmount = func() { c.unmount(false) }
+ }
+
+ statInfo, resolvedRoot, resolvedPath, err := c.stat(ctx, mountPoint, path)
+ if err != nil {
+ unmount()
+ return nil, err
+ }
+
+ idMappings, idPair, err := getIDMappingsAndPair(c, mountPoint)
+ if err != nil {
+ unmount()
+ return nil, err
+ }
+
+ logrus.Debugf("Container copy *from* %q (resolved: %q) on container %q (ID: %s)", path, resolvedPath, c.Name(), c.ID())
+
+ return func() error {
+ defer unmount()
+ getOptions := buildahCopiah.GetOptions{
+ // Unless the specified points to ".", we want to copy the base directory.
+ KeepDirectoryNames: statInfo.IsDir && filepath.Base(path) != ".",
+ UIDMap: idMappings.UIDMap,
+ GIDMap: idMappings.GIDMap,
+ ChownDirs: idPair,
+ ChownFiles: idPair,
+ Excludes: []string{"dev", "proc", "sys"},
+ }
+ return c.joinMountAndExec(ctx,
+ func() error {
+ return buildahCopiah.Get(resolvedRoot, "", getOptions, []string{resolvedPath}, writer)
+ },
+ )
+ }, nil
+}
+
+// getIDMappingsAndPair returns the ID mappings for the container and the host
+// ID pair.
+func getIDMappingsAndPair(container *Container, containerMount string) (*storage.IDMappingOptions, *idtools.IDPair, error) {
+ user, err := getContainerUser(container, containerMount)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ idMappingOpts, err := container.IDMappings()
+ if err != nil {
+ return nil, nil, err
+ }
+
+ hostUID, hostGID, err := util.GetHostIDs(idtoolsToRuntimeSpec(idMappingOpts.UIDMap), idtoolsToRuntimeSpec(idMappingOpts.GIDMap), user.UID, user.GID)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ idPair := idtools.IDPair{UID: int(hostUID), GID: int(hostGID)}
+ return &idMappingOpts, &idPair, nil
+}
+
+// getContainerUser returns the specs.User of the container.
+func getContainerUser(container *Container, mountPoint string) (specs.User, error) {
+ userspec := container.Config().User
+
+ uid, gid, _, err := chrootuser.GetUser(mountPoint, userspec)
+ u := specs.User{
+ UID: uid,
+ GID: gid,
+ Username: userspec,
+ }
+
+ if !strings.Contains(userspec, ":") {
+ groups, err2 := chrootuser.GetAdditionalGroupsForUser(mountPoint, uint64(u.UID))
+ if err2 != nil {
+ if errors.Cause(err2) != chrootuser.ErrNoSuchUser && err == nil {
+ err = err2
+ }
+ } else {
+ u.AdditionalGids = groups
+ }
+ }
+
+ return u, err
+}
+
+// idtoolsToRuntimeSpec converts idtools ID mapping to the one of the runtime spec.
+func idtoolsToRuntimeSpec(idMaps []idtools.IDMap) (convertedIDMap []specs.LinuxIDMapping) {
+ for _, idmap := range idMaps {
+ tempIDMap := specs.LinuxIDMapping{
+ ContainerID: uint32(idmap.ContainerID),
+ HostID: uint32(idmap.HostID),
+ Size: uint32(idmap.Size),
+ }
+ convertedIDMap = append(convertedIDMap, tempIDMap)
+ }
+ return convertedIDMap
+}
+
+// joinMountAndExec executes the specified function `f` inside the container's
+// mount and PID namespace. That allows for having the exact view on the
+// container's file system.
+//
+// Note, if the container is not running `f()` will be executed as is.
+func (c *Container) joinMountAndExec(ctx context.Context, f func() error) error {
+ if c.state.State != define.ContainerStateRunning {
+ return f()
+ }
+
+ // Container's running, so we need to execute `f()` inside its mount NS.
+ errChan := make(chan error)
+ go func() {
+ runtime.LockOSThread()
+
+ // Join the mount and PID NS of the container.
+ getFD := func(ns LinuxNS) (*os.File, error) {
+ nsPath, err := c.namespacePath(ns)
+ if err != nil {
+ return nil, err
+ }
+ return os.Open(nsPath)
+ }
+
+ mountFD, err := getFD(MountNS)
+ if err != nil {
+ errChan <- err
+ return
+ }
+ defer mountFD.Close()
+
+ pidFD, err := getFD(PIDNS)
+ if err != nil {
+ errChan <- err
+ return
+ }
+ defer pidFD.Close()
+ if err := unix.Unshare(unix.CLONE_NEWNS); err != nil {
+ errChan <- err
+ return
+ }
+ if err := unix.Setns(int(pidFD.Fd()), unix.CLONE_NEWPID); err != nil {
+ errChan <- err
+ return
+ }
+
+ if err := unix.Setns(int(mountFD.Fd()), unix.CLONE_NEWNS); err != nil {
+ errChan <- err
+ return
+ }
+
+ // Last but not least, execute the workload.
+ errChan <- f()
+ }()
+ return <-errChan
+}
diff --git a/libpod/container_copy_unsupported.go b/libpod/container_copy_unsupported.go
new file mode 100644
index 000000000..b2bdd3e3d
--- /dev/null
+++ b/libpod/container_copy_unsupported.go
@@ -0,0 +1,16 @@
+// +build !linux
+
+package libpod
+
+import (
+ "context"
+ "io"
+)
+
+func (c *Container) copyFromArchive(ctx context.Context, path string, reader io.Reader) (func() error, error) {
+ return nil, nil
+}
+
+func (c *Container) copyToArchive(ctx context.Context, path string, writer io.Writer) (func() error, error) {
+ return nil, nil
+}
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 7e8226de4..a7da7f395 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -2086,6 +2086,10 @@ func (c *Container) setupOCIHooks(ctx context.Context, config *spec.Spec) (map[s
// mount mounts the container's root filesystem
func (c *Container) mount() (string, error) {
+ if c.state.State == define.ContainerStateRemoving {
+ return "", errors.Wrapf(define.ErrCtrStateInvalid, "cannot mount container %s as it is being removed", c.ID())
+ }
+
mountPoint, err := c.runtime.storageService.MountContainerImage(c.ID())
if err != nil {
return "", errors.Wrapf(err, "error mounting storage for container %s", c.ID())
diff --git a/libpod/container_path_resolution.go b/libpod/container_path_resolution.go
index 5245314ae..d798963b1 100644
--- a/libpod/container_path_resolution.go
+++ b/libpod/container_path_resolution.go
@@ -1,3 +1,4 @@
+// +linux
package libpod
import (
@@ -10,6 +11,19 @@ import (
"github.com/sirupsen/logrus"
)
+// pathAbs returns an absolute path. If the specified path is
+// relative, it will be resolved relative to the container's working dir.
+func (c *Container) pathAbs(path string) string {
+ if !filepath.IsAbs(path) {
+ // If the containerPath is not absolute, it's relative to the
+ // container's working dir. To be extra careful, let's first
+ // join the working dir with "/", and the add the containerPath
+ // to it.
+ path = filepath.Join(filepath.Join("/", c.WorkingDir()), path)
+ }
+ return path
+}
+
// resolveContainerPaths resolves the container's mount point and the container
// path as specified by the user. Both may resolve to paths outside of the
// container's mount point when the container path hits a volume or bind mount.
@@ -20,14 +34,7 @@ import (
// the host).
func (c *Container) resolvePath(mountPoint string, containerPath string) (string, string, error) {
// Let's first make sure we have a path relative to the mount point.
- pathRelativeToContainerMountPoint := containerPath
- if !filepath.IsAbs(containerPath) {
- // If the containerPath is not absolute, it's relative to the
- // container's working dir. To be extra careful, let's first
- // join the working dir with "/", and the add the containerPath
- // to it.
- pathRelativeToContainerMountPoint = filepath.Join(filepath.Join("/", c.WorkingDir()), containerPath)
- }
+ pathRelativeToContainerMountPoint := c.pathAbs(containerPath)
resolvedPathOnTheContainerMountPoint := filepath.Join(mountPoint, pathRelativeToContainerMountPoint)
pathRelativeToContainerMountPoint = strings.TrimPrefix(pathRelativeToContainerMountPoint, mountPoint)
pathRelativeToContainerMountPoint = filepath.Join("/", pathRelativeToContainerMountPoint)
diff --git a/libpod/container_stat_linux.go b/libpod/container_stat_linux.go
new file mode 100644
index 000000000..307b75c14
--- /dev/null
+++ b/libpod/container_stat_linux.go
@@ -0,0 +1,157 @@
+// +build linux
+
+package libpod
+
+import (
+ "context"
+ "os"
+ "path/filepath"
+ "strings"
+
+ "github.com/containers/buildah/copier"
+ "github.com/containers/podman/v3/libpod/define"
+ "github.com/containers/podman/v3/pkg/copy"
+ "github.com/pkg/errors"
+)
+
+// statInsideMount stats the specified path *inside* the container's mount and PID
+// namespace. It returns the file info along with the resolved root ("/") and
+// the resolved path (relative to the root).
+func (c *Container) statInsideMount(ctx context.Context, containerPath string) (*copier.StatForItem, string, string, error) {
+ resolvedRoot := "/"
+ resolvedPath := c.pathAbs(containerPath)
+ var statInfo *copier.StatForItem
+
+ err := c.joinMountAndExec(ctx,
+ func() error {
+ var statErr error
+ statInfo, statErr = secureStat(resolvedRoot, resolvedPath)
+ return statErr
+ },
+ )
+
+ return statInfo, resolvedRoot, resolvedPath, err
+}
+
+// statOnHost stats the specified path *on the host*. It returns the file info
+// along with the resolved root and the resolved path. Both paths are absolute
+// to the host's root. Note that the paths may resolved outside the
+// container's mount point (e.g., to a volume or bind mount).
+func (c *Container) statOnHost(ctx context.Context, mountPoint string, containerPath string) (*copier.StatForItem, string, string, error) {
+ // Now resolve the container's path. It may hit a volume, it may hit a
+ // bind mount, it may be relative.
+ resolvedRoot, resolvedPath, err := c.resolvePath(mountPoint, containerPath)
+ if err != nil {
+ return nil, "", "", err
+ }
+
+ statInfo, err := secureStat(resolvedRoot, resolvedPath)
+ return statInfo, resolvedRoot, resolvedPath, err
+}
+
+func (c *Container) stat(ctx context.Context, containerMountPoint string, containerPath string) (*define.FileInfo, string, string, error) {
+ var (
+ resolvedRoot string
+ resolvedPath string
+ absContainerPath string
+ statInfo *copier.StatForItem
+ statErr error
+ )
+
+ // Make sure that "/" copies the *contents* of the mount point and not
+ // the directory.
+ if containerPath == "/" {
+ containerPath = "/."
+ }
+
+ if c.state.State == define.ContainerStateRunning {
+ // If the container is running, we need to join it's mount namespace
+ // and stat there.
+ statInfo, resolvedRoot, resolvedPath, statErr = c.statInsideMount(ctx, containerPath)
+ } else {
+ // If the container is NOT running, we need to resolve the path
+ // on the host.
+ statInfo, resolvedRoot, resolvedPath, statErr = c.statOnHost(ctx, containerMountPoint, containerPath)
+ }
+
+ if statErr != nil {
+ if statInfo == nil {
+ return nil, "", "", statErr
+ }
+ // Not all errors from secureStat map to ErrNotExist, so we
+ // have to look into the error string. Turning it into an
+ // ENOENT let's the API handlers return the correct status code
+ // which is crucial for the remote client.
+ if os.IsNotExist(statErr) || strings.Contains(statErr.Error(), "o such file or directory") {
+ statErr = copy.ErrENOENT
+ }
+ }
+
+ if statInfo.IsSymlink {
+ // Evaluated symlinks are always relative to the container's mount point.
+ absContainerPath = statInfo.ImmediateTarget
+ } else if strings.HasPrefix(resolvedPath, containerMountPoint) {
+ // If the path is on the container's mount point, strip it off.
+ absContainerPath = strings.TrimPrefix(resolvedPath, containerMountPoint)
+ absContainerPath = filepath.Join("/", absContainerPath)
+ } else {
+ // No symlink and not on the container's mount point, so let's
+ // move it back to the original input. It must have evaluated
+ // to a volume or bind mount but we cannot return host paths.
+ absContainerPath = containerPath
+ }
+
+ // Preserve the base path as specified by the user. The `filepath`
+ // packages likes to remove trailing slashes and dots that are crucial
+ // to the copy logic.
+ absContainerPath = copy.PreserveBasePath(containerPath, absContainerPath)
+ resolvedPath = copy.PreserveBasePath(containerPath, resolvedPath)
+
+ info := &define.FileInfo{
+ IsDir: statInfo.IsDir,
+ Name: filepath.Base(absContainerPath),
+ Size: statInfo.Size,
+ Mode: statInfo.Mode,
+ ModTime: statInfo.ModTime,
+ LinkTarget: absContainerPath,
+ }
+
+ return info, resolvedRoot, resolvedPath, statErr
+}
+
+// secureStat extracts file info for path in a chroot'ed environment in root.
+func secureStat(root string, path string) (*copier.StatForItem, error) {
+ var glob string
+ var err error
+
+ // If root and path are equal, then dir must be empty and the glob must
+ // be ".".
+ if filepath.Clean(root) == filepath.Clean(path) {
+ glob = "."
+ } else {
+ glob, err = filepath.Rel(root, path)
+ if err != nil {
+ return nil, err
+ }
+ }
+
+ globStats, err := copier.Stat(root, "", copier.StatOptions{}, []string{glob})
+ if err != nil {
+ return nil, err
+ }
+
+ if len(globStats) != 1 {
+ return nil, errors.Errorf("internal error: secureStat: expected 1 item but got %d", len(globStats))
+ }
+
+ stat, exists := globStats[0].Results[glob] // only one glob passed, so that's okay
+ if !exists {
+ return nil, copy.ErrENOENT
+ }
+
+ var statErr error
+ if stat.Error != "" {
+ statErr = errors.New(stat.Error)
+ }
+ return stat, statErr
+}
diff --git a/libpod/container_stat_unsupported.go b/libpod/container_stat_unsupported.go
new file mode 100644
index 000000000..c002e4d32
--- /dev/null
+++ b/libpod/container_stat_unsupported.go
@@ -0,0 +1,13 @@
+// +build !linux
+
+package libpod
+
+import (
+ "context"
+
+ "github.com/containers/podman/v3/libpod/define"
+)
+
+func (c *Container) stat(ctx context.Context, containerMountPoint string, containerPath string) (*define.FileInfo, string, string, error) {
+ return nil, "", "", nil
+}
diff --git a/libpod/define/fileinfo.go b/libpod/define/fileinfo.go
new file mode 100644
index 000000000..2c7b6fe99
--- /dev/null
+++ b/libpod/define/fileinfo.go
@@ -0,0 +1,16 @@
+package define
+
+import (
+ "os"
+ "time"
+)
+
+// FileInfo describes the attributes of a file or diretory.
+type FileInfo struct {
+ Name string `json:"name"`
+ Size int64 `json:"size"`
+ Mode os.FileMode `json:"mode"`
+ ModTime time.Time `json:"mtime"`
+ IsDir bool `json:"isDir"`
+ LinkTarget string `json:"linkTarget"`
+}