Add kpod-mount and kpod-umount to mount and umount container images

This command will allow users to manipulate and examine the container
images from outside of the container.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

cmd/kpod/umount.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	umountCommand = cli.Command{
+		Name:        "umount",
+		Aliases:     []string{"unmount"},
+		Usage:       "Unmount a working container's root filesystem",
+		Description: "Unmounts a working container's root filesystem",
+		Action:      umountCmd,
+		ArgsUsage:   "CONTAINER-NAME-OR-ID",
+	}
+)
+
+func umountCmd(c *cli.Context) error {
+	args := c.Args()
+	if len(args) == 0 {
+		return errors.Errorf("container ID must be specified")
+	}
+	if len(args) > 1 {
+		return errors.Errorf("too many arguments specified")
+	}
+	config, err := getConfig(c)
+	if err != nil {
+		return errors.Wrapf(err, "Could not get config")
+	}
+	store, err := getStore(config)
+	if err != nil {
+		return err
+	}
+
+	err = store.Unmount(args[0])
+	if err != nil {
+		return errors.Wrapf(err, "error unmounting container %q", args[0])
+	}
+	return nil
+}