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>

1 files changed, 310 insertions, 8 deletions

diff --git a/cmd/podman/containers/cp.go b/cmd/podman/containers/cp.go
index 9b0a01a2f..e0161824f 100644
--- a/cmd/podman/containers/cp.go
+++ b/cmd/podman/containers/cp.go
@@ -1,19 +1,34 @@
 package containers
 
 import (
+	"io"
+	"io/ioutil"
+	"os"
+	"os/user"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	buildahCopiah "github.com/containers/buildah/copier"
 	"github.com/containers/podman/v2/cmd/podman/common"
 	"github.com/containers/podman/v2/cmd/podman/registry"
+	"github.com/containers/podman/v2/pkg/copy"
 	"github.com/containers/podman/v2/pkg/domain/entities"
+	"github.com/containers/podman/v2/pkg/errorhandling"
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
 var (
-	cpDescription = `Command copies the contents of SRC_PATH to the DEST_PATH.
+	cpDescription = `Copy the contents of SRC_PATH to the DEST_PATH.
 
-  You can copy from the container's file system to the local machine or the reverse, from the local filesystem to the container. If "-" is specified for either the SRC_PATH or DEST_PATH, you can also stream a tar archive from STDIN or to STDOUT. The CONTAINER can be a running or stopped container.  The SRC_PATH or DEST_PATH can be a file or directory.
+  You can copy from the container's file system to the local machine or the reverse, from the local filesystem to the container. If "-" is specified for either the SRC_PATH or DEST_PATH, you can also stream a tar archive from STDIN or to STDOUT. The CONTAINER can be a running or stopped container. The SRC_PATH or DEST_PATH can be a file or a directory.
 `
 	cpCommand = &cobra.Command{
-		Use:               "cp [options] [CONTAINER:]SRC_PATH [CONTAINER:]DEST_PATH",
+		Use:               "cp [CONTAINER:]SRC_PATH [CONTAINER:]DEST_PATH",
 		Short:             "Copy files/folders between a container and the local filesystem",
 		Long:              cpDescription,
 		Args:              cobra.ExactArgs(2),
@@ -39,19 +54,21 @@ var (
 
 func cpFlags(cmd *cobra.Command) {
 	flags := cmd.Flags()
-	flags.BoolVar(&cpOpts.Extract, "extract", false, "Extract the tar file into the destination directory.")
-	flags.BoolVar(&cpOpts.Pause, "pause", true, "Pause the container while copying")
+	flags.BoolVar(&cpOpts.Extract, "extract", false, "Deprecated...")
+	flags.BoolVar(&cpOpts.Pause, "pause", true, "Deorecated")
+	_ = flags.MarkHidden("extract")
+	_ = flags.MarkHidden("pause")
 }
 
 func init() {
 	registry.Commands = append(registry.Commands, registry.CliCommand{
-		Mode:    []entities.EngineMode{entities.ABIMode},
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
 		Command: cpCommand,
 	})
 	cpFlags(cpCommand)
 
 	registry.Commands = append(registry.Commands, registry.CliCommand{
-		Mode:    []entities.EngineMode{entities.ABIMode},
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
 		Command: containerCpCommand,
 		Parent:  containerCmd,
 	})
@@ -59,5 +76,290 @@ func init() {
 }
 
 func cp(cmd *cobra.Command, args []string) error {
-	return registry.ContainerEngine().ContainerCp(registry.GetContext(), args[0], args[1], cpOpts)
+	// Parse user input.
+	sourceContainerStr, sourcePath, destContainerStr, destPath, err := copy.ParseSourceAndDestination(args[0], args[1])
+	if err != nil {
+		return err
+	}
+
+	if len(sourceContainerStr) > 0 {
+		return copyFromContainer(sourceContainerStr, sourcePath, destPath)
+	}
+
+	return copyToContainer(destContainerStr, destPath, sourcePath)
+}
+
+// containerMustExist returns an error if the specified container does not
+// exist.
+func containerMustExist(container string) error {
+	exists, err := registry.ContainerEngine().ContainerExists(registry.GetContext(), container, entities.ContainerExistsOptions{})
+	if err != nil {
+		return err
+	}
+	if !exists.Value {
+		return errors.Errorf("container %q does not exist", container)
+	}
+	return nil
+}
+
+// doCopy executes the two functions in parallel to copy data from A to B and
+// joins the errors if any.
+func doCopy(funcA func() error, funcB func() error) error {
+	errChan := make(chan error)
+	go func() {
+		errChan <- funcA()
+	}()
+	var copyErrors []error
+	copyErrors = append(copyErrors, funcB())
+	copyErrors = append(copyErrors, <-errChan)
+	return errorhandling.JoinErrors(copyErrors)
+}
+
+// copyFromContainer copies from the containerPath on the container to hostPath.
+func copyFromContainer(container string, containerPath string, hostPath string) error {
+	if err := containerMustExist(container); err != nil {
+		return err
+	}
+
+	if hostPath == "-" {
+		hostPath = os.Stdout.Name()
+	}
+
+	containerInfo, err := registry.ContainerEngine().ContainerStat(registry.GetContext(), container, containerPath)
+	if err != nil {
+		return errors.Wrapf(err, "%q could not be found on container %s", containerPath, container)
+	}
+
+	var hostBaseName string
+	hostInfo, hostInfoErr := copy.ResolveHostPath(hostPath)
+	if hostInfoErr != nil {
+		if strings.HasSuffix(hostPath, "/") {
+			return errors.Wrapf(hostInfoErr, "%q could not be found on the host", hostPath)
+		}
+		// If it doesn't exist, then let's have a look at the parent dir.
+		parentDir := filepath.Dir(hostPath)
+		hostInfo, err = copy.ResolveHostPath(parentDir)
+		if err != nil {
+			return errors.Wrapf(hostInfoErr, "%q could not be found on the host", hostPath)
+		}
+		// If the specified path does not exist, we need to assume that
+		// it'll be created while copying.  Hence, we use it as the
+		// base path.
+		hostBaseName = filepath.Base(hostPath)
+	} else {
+		// If the specified path exists on the host, we must use its
+		// base path as it may have changed due to symlink evaluations.
+		hostBaseName = filepath.Base(hostInfo.LinkTarget)
+	}
+
+	reader, writer := io.Pipe()
+	hostCopy := func() error {
+		defer reader.Close()
+		if hostInfo.LinkTarget == os.Stdout.Name() {
+			_, err := io.Copy(os.Stdout, reader)
+			return err
+		}
+
+		groot, err := user.Current()
+		if err != nil {
+			return err
+		}
+
+		// Set the {G,U}ID.  Let's be tolerant towards the different
+		// operating systems and only log the errors, so we can debug
+		// if necessary.
+		idPair := idtools.IDPair{}
+		if i, err := strconv.Atoi(groot.Uid); err == nil {
+			idPair.UID = i
+		} else {
+			logrus.Debugf("Error converting UID %q to int: %v", groot.Uid, err)
+		}
+		if i, err := strconv.Atoi(groot.Gid); err == nil {
+			idPair.GID = i
+		} else {
+			logrus.Debugf("Error converting GID %q to int: %v", groot.Gid, err)
+		}
+
+		putOptions := buildahCopiah.PutOptions{
+			ChownDirs:  &idPair,
+			ChownFiles: &idPair,
+		}
+		if !containerInfo.IsDir && (!hostInfo.IsDir || hostInfoErr != nil) {
+			// If we're having a file-to-file copy, make sure to
+			// rename accordingly.
+			putOptions.Rename = map[string]string{filepath.Base(containerInfo.LinkTarget): hostBaseName}
+		}
+		dir := hostInfo.LinkTarget
+		if !hostInfo.IsDir {
+			dir = filepath.Dir(dir)
+		}
+		if err := buildahCopiah.Put(dir, "", putOptions, reader); err != nil {
+			return errors.Wrap(err, "error copying to host")
+		}
+		return nil
+	}
+
+	containerCopy := func() error {
+		defer writer.Close()
+		copyFunc, err := registry.ContainerEngine().ContainerCopyToArchive(registry.GetContext(), container, containerInfo.LinkTarget, writer)
+		if err != nil {
+			return err
+		}
+		if err := copyFunc(); err != nil {
+			return errors.Wrap(err, "error copying from container")
+		}
+		return nil
+	}
+	return doCopy(containerCopy, hostCopy)
+}
+
+// copyToContainer copies the hostPath to containerPath on the container.
+func copyToContainer(container string, containerPath string, hostPath string) error {
+	if err := containerMustExist(container); err != nil {
+		return err
+	}
+
+	isStdin := false
+	if hostPath == "-" {
+		hostPath = os.Stdin.Name()
+		isStdin = true
+	} else if hostPath == os.Stdin.Name() {
+		isStdin = true
+	}
+
+	// Make sure that host path exists.
+	hostInfo, err := copy.ResolveHostPath(hostPath)
+	if err != nil {
+		return errors.Wrapf(err, "%q could not be found on the host", hostPath)
+	}
+
+	// If the path on the container does not exist.  We need to make sure
+	// that it's parent directory exists.  The destination may be created
+	// while copying.
+	var containerBaseName string
+	containerInfo, containerInfoErr := registry.ContainerEngine().ContainerStat(registry.GetContext(), container, containerPath)
+	if containerInfoErr != nil {
+		if strings.HasSuffix(containerPath, "/") {
+			return errors.Wrapf(containerInfoErr, "%q could not be found on container %s", containerPath, container)
+		}
+		if isStdin {
+			return errors.New("destination must be a directory when copying from stdin")
+		}
+		// NOTE: containerInfo may actually be set.  That happens when
+		// the container path is a symlink into nirvana.  In that case,
+		// we must use the symlinked path instead.
+		path := containerPath
+		if containerInfo != nil {
+			containerBaseName = filepath.Base(containerInfo.LinkTarget)
+			path = containerInfo.LinkTarget
+		} else {
+			containerBaseName = filepath.Base(containerPath)
+		}
+
+		parentDir, err := containerParentDir(container, path)
+		if err != nil {
+			return errors.Wrapf(err, "could not determine parent dir of %q on container %s", path, container)
+		}
+		containerInfo, err = registry.ContainerEngine().ContainerStat(registry.GetContext(), container, parentDir)
+		if err != nil {
+			return errors.Wrapf(err, "%q could not be found on container %s", containerPath, container)
+		}
+	} else {
+		// If the specified path exists on the container, we must use
+		// its base path as it may have changed due to symlink
+		// evaluations.
+		containerBaseName = filepath.Base(containerInfo.LinkTarget)
+	}
+
+	var stdinFile string
+	if isStdin {
+		if !containerInfo.IsDir {
+			return errors.New("destination must be a directory when copying from stdin")
+		}
+
+		// Copy from stdin to a temporary file *before* throwing it
+		// over the wire.  This allows for proper client-side error
+		// reporting.
+		tmpFile, err := ioutil.TempFile("", "")
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(tmpFile, os.Stdin)
+		if err != nil {
+			return err
+		}
+		if err = tmpFile.Close(); err != nil {
+			return err
+		}
+		if !archive.IsArchivePath(tmpFile.Name()) {
+			return errors.New("source must be a (compressed) tar archive when copying from stdin")
+		}
+		stdinFile = tmpFile.Name()
+	}
+
+	reader, writer := io.Pipe()
+	hostCopy := func() error {
+		defer writer.Close()
+		if isStdin {
+			stream, err := os.Open(stdinFile)
+			if err != nil {
+				return err
+			}
+			defer stream.Close()
+			_, err = io.Copy(writer, stream)
+			return err
+		}
+
+		getOptions := buildahCopiah.GetOptions{
+			// Unless the specified path ends with ".", we want to copy the base directory.
+			KeepDirectoryNames: !strings.HasSuffix(hostPath, "."),
+		}
+		if !hostInfo.IsDir && (!containerInfo.IsDir || containerInfoErr != nil) {
+			// If we're having a file-to-file copy, make sure to
+			// rename accordingly.
+			getOptions.Rename = map[string]string{filepath.Base(hostInfo.LinkTarget): containerBaseName}
+		}
+		if err := buildahCopiah.Get("/", "", getOptions, []string{hostInfo.LinkTarget}, writer); err != nil {
+			return errors.Wrap(err, "error copying from host")
+		}
+		return nil
+	}
+
+	containerCopy := func() error {
+		defer reader.Close()
+		target := containerInfo.FileInfo.LinkTarget
+		if !containerInfo.IsDir {
+			target = filepath.Dir(target)
+		}
+
+		copyFunc, err := registry.ContainerEngine().ContainerCopyFromArchive(registry.GetContext(), container, target, reader)
+		if err != nil {
+			return err
+		}
+		if err := copyFunc(); err != nil {
+			return errors.Wrap(err, "error copying to container")
+		}
+		return nil
+	}
+
+	return doCopy(hostCopy, containerCopy)
+}
+
+// containerParentDir returns the parent directory of the specified path on the
+// container.  If the path is relative, it will be resolved relative to the
+// container's working directory (or "/" if the work dir isn't set).
+func containerParentDir(container string, containerPath string) (string, error) {
+	if filepath.IsAbs(containerPath) {
+		return filepath.Dir(containerPath), nil
+	}
+	inspectData, _, err := registry.ContainerEngine().ContainerInspect(registry.GetContext(), []string{container}, entities.InspectOptions{})
+	if err != nil {
+		return "", err
+	}
+	if len(inspectData) != 1 {
+		return "", errors.Errorf("inspecting container %q: expected 1 data item but got %d", container, len(inspectData))
+	}
+	workDir := filepath.Join("/", inspectData[0].Config.WorkingDir)
+	workDir = filepath.Join(workDir, containerPath)
+	return filepath.Dir(workDir), nil
 }