Implement --image-volumes for create and run

--image-volumes tells podman what to do with the image volumes in the image config
There are 3 options: bind, tmpfs, and ignore
bind puts the volume contents in /var/lib/containers/storage/container-id/volumes/vol-dir
and bind mounts it into the container at /vol-dir
tmpfs mounts /vol-dir as a tmps into the container
ignore doesn't mount the image volumes onto the container

Signed-off-by: umohnani8 <umohnani@redhat.com>

Closes: #377
Approved by: rhatdan

3 files changed, 64 insertions, 1 deletions

diff --git a/libpod/container_api.go b/libpod/container_api.go
index 6fdc45589..149197470 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -144,6 +144,13 @@ func (c *Container) Init() (err error) {
 	}
 	g.AddMount(hostnameMnt)
 
+	// Bind builtin image volumes
+	if c.config.ImageVolumes {
+		if err = c.addImageVolumes(&g); err != nil {
+			return errors.Wrapf(err, "error mounting image volumes")
+		}
+	}
+
 	if c.config.User != "" {
 		if !c.state.Mounted {
 			return errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to translate User field", c.ID())
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 6e9852d1e..e22d36f99 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -12,10 +12,12 @@ import (
 
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/chrootarchive"
 	"github.com/docker/docker/pkg/mount"
 	"github.com/docker/docker/pkg/namesgenerator"
 	"github.com/docker/docker/pkg/stringid"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/opencontainers/runtime-tools/generate"
 	"github.com/opencontainers/selinux/go-selinux/label"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -271,6 +273,49 @@ func (c *Container) export(path string) error {
 	return err
 }
 
+func (c *Container) addImageVolumes(g *generate.Generator) error {
+	mountPoint := c.state.Mountpoint
+	if !c.state.Mounted {
+		return errors.Wrapf(ErrInternal, "container is not mounted")
+	}
+
+	imageStorage, err := c.runtime.getImage(c.config.RootfsImageID)
+	if err != nil {
+		return err
+	}
+	imageData, err := c.runtime.getImageInspectInfo(*imageStorage)
+	if err != nil {
+		return err
+	}
+
+	for k := range imageData.ContainerConfig.Volumes {
+		mount := spec.Mount{
+			Destination: k,
+			Type:        "bind",
+			Options:     []string{"rbind", "rw"},
+		}
+		if MountExists(g.Mounts(), k) {
+			continue
+		}
+		volumePath := filepath.Join(c.config.StaticDir, "volumes", k)
+		if _, err := os.Stat(volumePath); os.IsNotExist(err) {
+			if err = os.MkdirAll(volumePath, 0755); err != nil {
+				return errors.Wrapf(err, "error creating directory %q for volume %q in container %q", volumePath, k, c.ID)
+			}
+			if err = label.Relabel(volumePath, c.config.MountLabel, false); err != nil {
+				return errors.Wrapf(err, "error relabeling directory %q for volume %q in container %q", volumePath, k, c.ID)
+			}
+			srcPath := filepath.Join(mountPoint, k)
+			if err = chrootarchive.NewArchiver(nil).CopyWithTar(srcPath, volumePath); err != nil && !os.IsNotExist(err) {
+				return errors.Wrapf(err, "error populating directory %q for volume %q in container %q using contents of %q", volumePath, k, c.ID, srcPath)
+			}
+			mount.Source = volumePath
+		}
+		g.AddMount(mount)
+	}
+	return nil
+}
+
 // Get path of artifact with a given name for this container
 func (c *Container) getArtifactPath(name string) string {
 	return filepath.Join(c.config.StaticDir, artifactsDir, name)
diff --git a/libpod/util.go b/libpod/util.go
index 1a033a940..0c6700fbf 100644
--- a/libpod/util.go
+++ b/libpod/util.go
@@ -4,13 +4,14 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"time"
 
 	"github.com/containers/image/signature"
 	"github.com/containers/image/types"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
-	"strconv"
 )
 
 // Runtime API constants
@@ -96,3 +97,13 @@ func RemoveScientificNotationFromFloat(x float64) (float64, error) {
 	}
 	return result, nil
 }
+
+// MountExists returns true if dest exists in the list of mounts
+func MountExists(specMounts []spec.Mount, dest string) bool {
+	for _, m := range specMounts {
+		if m.Destination == dest {
+			return true
+		}
+	}
+	return false
+}