remote copy

Implement `podman-remote cp` and break out the logic from the previously
added `pkg/copy` into it's basic building blocks and move them up into
the `ContainerEngine` interface and `cmd/podman`.

The `--pause` and `--extract` flags are now deprecated and turned into
nops.

Note that this commit is vendoring a non-release version of Buildah to
pull in updates to the copier package.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containers/buildah/run_linux.go

@@ -506,8 +506,14 @@ func (b *Builder) setupMounts(mountPoint string, spec *specs.Spec, bundlePath st
 		return err
 	}
 
+	// Get host UID and GID of the container process.
+	processUID, processGID, err := util.GetHostIDs(spec.Linux.UIDMappings, spec.Linux.GIDMappings, spec.Process.User.UID, spec.Process.User.GID)
+	if err != nil {
+		return err
+	}
+
 	// Get the list of explicitly-specified volume mounts.
-	volumes, err := b.runSetupVolumeMounts(spec.Linux.MountLabel, volumeMounts, optionMounts, int(rootUID), int(rootGID))
+	volumes, err := b.runSetupVolumeMounts(spec.Linux.MountLabel, volumeMounts, optionMounts, int(rootUID), int(rootGID), int(processUID), int(processGID))
 	if err != nil {
 		return err
 	}
@@ -1687,7 +1693,7 @@ func (b *Builder) cleanupTempVolumes() {
 	}
 }
 
-func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string, optionMounts []specs.Mount, rootUID, rootGID int) (mounts []specs.Mount, Err error) {
+func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string, optionMounts []specs.Mount, rootUID, rootGID, processUID, processGID int) (mounts []specs.Mount, Err error) {
 
 	// Make sure the overlay directory is clean before running
 	containerDir, err := b.store.ContainerDirectory(b.ContainerID)
@@ -1699,7 +1705,7 @@ func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string,
 	}
 
 	parseMount := func(mountType, host, container string, options []string) (specs.Mount, error) {
-		var foundrw, foundro, foundz, foundZ, foundO bool
+		var foundrw, foundro, foundz, foundZ, foundO, foundU bool
 		var rootProp string
 		for _, opt := range options {
 			switch opt {
@@ -1713,6 +1719,8 @@ func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string,
 				foundZ = true
 			case "O":
 				foundO = true
+			case "U":
+				foundU = true
 			case "private", "rprivate", "slave", "rslave", "shared", "rshared":
 				rootProp = opt
 			}
@@ -1730,6 +1738,11 @@ func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string,
 				return specs.Mount{}, err
 			}
 		}
+		if foundU {
+			if err := chownSourceVolume(host, processUID, processGID); err != nil {
+				return specs.Mount{}, err
+			}
+		}
 		if foundO {
 			containerDir, err := b.store.ContainerDirectory(b.ContainerID)
 			if err != nil {
@@ -1746,6 +1759,14 @@ func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string,
 
 				b.TempVolumes[contentDir] = true
 			}
+
+			// If chown true, add correct ownership to the overlay temp directories.
+			if foundU {
+				if err := chownSourceVolume(contentDir, processUID, processGID); err != nil {
+					return specs.Mount{}, err
+				}
+			}
+
 			return overlayMount, err
 		}
 		if rootProp == "" {
@@ -1789,6 +1810,39 @@ func (b *Builder) runSetupVolumeMounts(mountLabel string, volumeMounts []string,
 	return mounts, nil
 }
 
+// chownSourceVolume changes the ownership of a volume source directory or file within the host.
+func chownSourceVolume(path string, UID, GID int) error {
+	fi, err := os.Lstat(path)
+	if err != nil {
+		// Skip if path does not exist
+		if os.IsNotExist(err) {
+			logrus.Debugf("error returning file info of %q: %v", path, err)
+			return nil
+		}
+		return err
+	}
+
+	currentUID := int(fi.Sys().(*syscall.Stat_t).Uid)
+	currentGID := int(fi.Sys().(*syscall.Stat_t).Gid)
+
+	if UID != currentUID || GID != currentGID {
+		err := filepath.Walk(path, func(filePath string, f os.FileInfo, err error) error {
+			return os.Lchown(filePath, UID, GID)
+		})
+
+		if err != nil {
+			// Skip if path does not exist
+			if os.IsNotExist(err) {
+				logrus.Debugf("error changing the uid and gid of %q: %v", path, err)
+				return nil
+			}
+			return err
+		}
+	}
+
+	return nil
+}
+
 func setupMaskedPaths(g *generate.Generator) {
 	for _, mp := range []string{
 		"/proc/acpi",