From 22aad9c87cf56b405f2d223827bf8eb26db5bc18 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Tue, 30 Jul 2013 11:05:06 -0700
Subject: [PATCH] builder/amazon/chroot: mount the root device

---
 builder/amazon/chroot/builder.go           |  1 +
 builder/amazon/chroot/step_mount_device.go | 71 ++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 builder/amazon/chroot/step_mount_device.go

diff --git a/builder/amazon/chroot/builder.go b/builder/amazon/chroot/builder.go
index ec344d938..9e03e6771 100644
--- a/builder/amazon/chroot/builder.go
+++ b/builder/amazon/chroot/builder.go
@@ -96,6 +96,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		&StepSourceAMIInfo{},
 		&StepCreateVolume{},
 		&StepAttachVolume{},
+		&StepMountDevice{},
 	}
 
 	// Run!
diff --git a/builder/amazon/chroot/step_mount_device.go b/builder/amazon/chroot/step_mount_device.go
new file mode 100644
index 000000000..4655c37c9
--- /dev/null
+++ b/builder/amazon/chroot/step_mount_device.go
@@ -0,0 +1,71 @@
+package chroot
+
+import (
+	"bytes"
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"log"
+	"os"
+	"os/exec"
+)
+
+// StepMountDevice mounts the attached device.
+//
+// Produces:
+//   mount_path string - The location where the volume was mounted.
+type StepMountDevice struct {
+	mountPath string
+}
+
+func (s *StepMountDevice) Run(state map[string]interface{}) multistep.StepAction {
+	config := state["config"].(*Config)
+	ui := state["ui"].(packer.Ui)
+	device := state["device"].(string)
+
+	mountPath := config.MountPath
+	log.Printf("Mount path: %s", mountPath)
+
+	if err := os.MkdirAll(mountPath, 0755); err != nil {
+		err := fmt.Errorf("Error creating mount directory: %s", err)
+		state["error"] = err
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
+	ui.Say("Mounting the root device...")
+	stderr := new(bytes.Buffer)
+	cmd := exec.Command("mount", device, mountPath)
+	cmd.Stderr = stderr
+	if err := cmd.Run(); err != nil {
+		err := fmt.Errorf(
+			"Error mounting root volume: %s\nStderr: %s", err, stderr.String())
+		state["error"] = err
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
+	return multistep.ActionContinue
+}
+
+func (s *StepMountDevice) Cleanup(state map[string]interface{}) {
+	if s.mountPath == "" {
+		return
+	}
+
+	ui := state["ui"].(packer.Ui)
+	ui.Say("Unmounting the root device...")
+
+	path, err := exec.LookPath("umount")
+	if err != nil {
+		ui.Error(fmt.Sprintf("Error umounting root device: %s", err))
+		return
+	}
+
+	cmd := exec.Command(path, s.mountPath)
+	if err := cmd.Run(); err != nil {
+		ui.Error(fmt.Sprintf(
+			"Error unmounting root device: %s", err))
+		return
+	}
+}