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-rw-r--r--pkg/domain/infra/abi/containers_stat.go251
1 files changed, 251 insertions, 0 deletions
diff --git a/pkg/domain/infra/abi/containers_stat.go b/pkg/domain/infra/abi/containers_stat.go
new file mode 100644
index 000000000..c9610d1b9
--- /dev/null
+++ b/pkg/domain/infra/abi/containers_stat.go
@@ -0,0 +1,251 @@
+package abi
+
+import (
+ "context"
+ "os"
+ "path/filepath"
+ "strings"
+
+ buildahCopiah "github.com/containers/buildah/copier"
+ "github.com/containers/podman/v2/libpod"
+ "github.com/containers/podman/v2/pkg/copy"
+ "github.com/containers/podman/v2/pkg/domain/entities"
+ securejoin "github.com/cyphar/filepath-securejoin"
+ "github.com/opencontainers/runtime-spec/specs-go"
+ "github.com/pkg/errors"
+ "github.com/sirupsen/logrus"
+)
+
+func (ic *ContainerEngine) containerStat(container *libpod.Container, containerPath string) (*entities.ContainerStatReport, string, string, error) {
+ containerMountPoint, err := container.Mount()
+ if err != nil {
+ return nil, "", "", err
+ }
+
+ // Make sure that "/" copies the *contents* of the mount point and not
+ // the directory.
+ if containerPath == "/" {
+ containerPath += "/."
+ }
+
+ // Now resolve the container's path. It may hit a volume, it may hit a
+ // bind mount, it may be relative.
+ resolvedRoot, resolvedContainerPath, err := resolveContainerPaths(container, containerMountPoint, containerPath)
+ if err != nil {
+ return nil, "", "", err
+ }
+
+ statInfo, statInfoErr := secureStat(resolvedRoot, resolvedContainerPath)
+ if statInfoErr != nil {
+ // 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 crucuial for the remote client.
+ if os.IsNotExist(err) || strings.Contains(statInfoErr.Error(), "o such file or directory") {
+ statInfoErr = copy.ENOENT
+ }
+ // If statInfo is nil, there's nothing we can do anymore. A
+ // non-nil statInfo may indicate a symlink where we must have
+ // a closer look.
+ if statInfo == nil {
+ return nil, "", "", statInfoErr
+ }
+ }
+
+ // Now make sure that the info's LinkTarget is relative to the
+ // container's mount.
+ var absContainerPath string
+
+ if statInfo.IsSymlink {
+ // Evaluated symlinks are always relative to the container's mount point.
+ absContainerPath = statInfo.ImmediateTarget
+ } else if strings.HasPrefix(resolvedContainerPath, containerMountPoint) {
+ // If the path is on the container's mount point, strip it off.
+ absContainerPath = strings.TrimPrefix(resolvedContainerPath, 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
+ }
+
+ // Now we need to make sure to preseve 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)
+ resolvedContainerPath = copy.PreserveBasePath(containerPath, resolvedContainerPath)
+
+ info := copy.FileInfo{
+ IsDir: statInfo.IsDir,
+ Name: filepath.Base(absContainerPath),
+ Size: statInfo.Size,
+ Mode: statInfo.Mode,
+ ModTime: statInfo.ModTime,
+ LinkTarget: absContainerPath,
+ }
+
+ return &entities.ContainerStatReport{FileInfo: info}, resolvedRoot, resolvedContainerPath, statInfoErr
+}
+
+func (ic *ContainerEngine) ContainerStat(ctx context.Context, nameOrID string, containerPath string) (*entities.ContainerStatReport, error) {
+ container, err := ic.Libpod.LookupContainer(nameOrID)
+ if err != nil {
+ return nil, err
+ }
+
+ defer func() {
+ if err := container.Unmount(false); err != nil {
+ logrus.Errorf("Error unmounting container: %v", err)
+ }
+ }()
+
+ statReport, _, _, err := ic.containerStat(container, containerPath)
+ return statReport, err
+}
+
+// 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.
+//
+// NOTE: We must take volumes and bind mounts into account as, regrettably, we
+// can copy to/from stopped containers. In that case, the volumes and bind
+// mounts are not present. For running containers, the runtime (e.g., runc or
+// crun) takes care of these mounts. For stopped ones, we need to do quite
+// some dance, as done below.
+func resolveContainerPaths(container *libpod.Container, 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("/", container.WorkingDir()), containerPath)
+ }
+ resolvedPathOnTheContainerMountPoint := filepath.Join(mountPoint, pathRelativeToContainerMountPoint)
+ pathRelativeToContainerMountPoint = strings.TrimPrefix(pathRelativeToContainerMountPoint, mountPoint)
+ pathRelativeToContainerMountPoint = filepath.Join("/", pathRelativeToContainerMountPoint)
+
+ // Now we have an "absolute container Path" but not yet resolved on the
+ // host (e.g., "/foo/bar/file.txt"). As mentioned above, we need to
+ // check if "/foo/bar/file.txt" is on a volume or bind mount. To do
+ // that, we need to walk *down* the paths to the root. Assuming
+ // volume-1 is mounted to "/foo" and volume-2 is mounted to "/foo/bar",
+ // we must select "/foo/bar". Once selected, we need to rebase the
+ // remainder (i.e, "/file.txt") on the volume's mount point on the
+ // host. Same applies to bind mounts.
+
+ searchPath := pathRelativeToContainerMountPoint
+ for {
+ volume, err := findVolume(container, searchPath)
+ if err != nil {
+ return "", "", err
+ }
+ if volume != nil {
+ logrus.Debugf("Container path %q resolved to volume %q on path %q", containerPath, volume.Name(), searchPath)
+ // We found a matching volume for searchPath. We now
+ // need to first find the relative path of our input
+ // path to the searchPath, and then join it with the
+ // volume's mount point.
+ pathRelativeToVolume := strings.TrimPrefix(pathRelativeToContainerMountPoint, searchPath)
+ absolutePathOnTheVolumeMount, err := securejoin.SecureJoin(volume.MountPoint(), pathRelativeToVolume)
+ if err != nil {
+ return "", "", err
+ }
+ return volume.MountPoint(), absolutePathOnTheVolumeMount, nil
+ }
+
+ if mount := findBindMount(container, searchPath); mount != nil {
+ logrus.Debugf("Container path %q resolved to bind mount %q:%q on path %q", containerPath, mount.Source, mount.Destination, searchPath)
+ // We found a matching bind mount for searchPath. We
+ // now need to first find the relative path of our
+ // input path to the searchPath, and then join it with
+ // the source of the bind mount.
+ pathRelativeToBindMount := strings.TrimPrefix(pathRelativeToContainerMountPoint, searchPath)
+ absolutePathOnTheBindMount, err := securejoin.SecureJoin(mount.Source, pathRelativeToBindMount)
+ if err != nil {
+ return "", "", err
+ }
+ return mount.Source, absolutePathOnTheBindMount, nil
+
+ }
+
+ if searchPath == "/" {
+ // Cannot go beyond "/", so we're done.
+ break
+ }
+
+ // Walk *down* the path (e.g., "/foo/bar/x" -> "/foo/bar").
+ searchPath = filepath.Dir(searchPath)
+ }
+
+ // No volume, no bind mount but just a normal path on the container.
+ return mountPoint, resolvedPathOnTheContainerMountPoint, nil
+}
+
+// findVolume checks if the specified container path matches a volume inside
+// the container. It returns a matching volume or nil.
+func findVolume(c *libpod.Container, containerPath string) (*libpod.Volume, error) {
+ runtime := c.Runtime()
+ cleanedContainerPath := filepath.Clean(containerPath)
+ for _, vol := range c.Config().NamedVolumes {
+ if cleanedContainerPath == filepath.Clean(vol.Dest) {
+ return runtime.GetVolume(vol.Name)
+ }
+ }
+ return nil, nil
+}
+
+// findBindMount checks if the specified container path matches a bind mount
+// inside the container. It returns a matching mount or nil.
+func findBindMount(c *libpod.Container, containerPath string) *specs.Mount {
+ cleanedPath := filepath.Clean(containerPath)
+ for _, m := range c.Config().Spec.Mounts {
+ if m.Type != "bind" {
+ continue
+ }
+ if cleanedPath == filepath.Clean(m.Destination) {
+ mount := m
+ return &mount
+ }
+ }
+ return nil
+}
+
+// secureStat extracts file info for path in a chroot'ed environment in root.
+func secureStat(root string, path string) (*buildahCopiah.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 := buildahCopiah.Stat(root, "", buildahCopiah.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.ENOENT
+ }
+
+ var statErr error
+ if stat.Error != "" {
+ statErr = errors.New(stat.Error)
+ }
+ return stat, statErr
+}