builder/amazon/chroot: use mountcommand configs

builder/amazon/chroot/builder.go

@@ -24,10 +24,13 @@ type Config struct {
 	common.PackerConfig    `mapstructure:",squash"`
 	awscommon.AccessConfig `mapstructure:",squash"`
 
-	SourceAmi          string `mapstructure:"source_ami"`
-	AttachedDevicePath string `mapstructure:"attached_device_path"`
-	DevicePath         string `mapstructure:"device_path"`
-	MountPath          string `mapstructure:"mount_path"`
+	AttachedDevicePath string   `mapstructure:"attached_device_path"`
+	ChrootMounts       []string `mapstructure:"chroot_mounts"`
+	DevicePath         string   `mapstructure:"device_path"`
+	MountCommand       string   `mapstructure:"mount_command"`
+	MountPath          string   `mapstructure:"mount_path"`
+	SourceAmi          string   `mapstructure:"source_ami"`
+	UnmountCommand     string   `mapstructure:"unmount_command"`
 }
 
 type Builder struct {
@@ -42,14 +45,36 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	// Defaults
+	if b.config.ChrootMounts == nil {
+		b.config.ChrootMounts = make([]string, 0)
+	}
+
+	if len(b.config.ChrootMounts) == 0 {
+		b.config.ChrootMounts = []string{
+			"{{.MountCommand}} -t proc proc {{.MountPath}}/proc",
+			"{{.MountCommand}} -t sysfs sysfs {{.MountPath}}/sys",
+			"{{.MountCommand}} -t bind /dev {{.MountPath}}/dev",
+			"{{.MountCommand}} -t devpts devpts {{.MountPath}}/dev/pts",
+			"{{.MountCommand}} -t binfmt_misc binfmt_misc {{.MountPath}}/proc/sys/fs/binfmt_misc",
+		}
+	}
+
 	if b.config.DevicePath == "" {
 		b.config.DevicePath = "/dev/sdh"
 	}
 
+	if b.config.MountCommand == "" {
+		b.config.MountCommand = "mount"
+	}
+
 	if b.config.MountPath == "" {
 		b.config.MountPath = "/var/packer-amazon-chroot/volumes/{{.Device}}"
 	}
 
+	if b.config.UnmountCommand == "" {
+		b.config.UnmountCommand = "umount"
+	}
+
 	// Accumulate any errors
 	errs := common.CheckUnusedConfig(md)
 	errs = packer.MultiErrorAppend(errs, b.config.AccessConfig.Prepare()...)

builder/amazon/chroot/step_mount_device.go

@@ -35,7 +35,8 @@ func (s *StepMountDevice) Run(state map[string]interface{}) multistep.StepAction
 
 	ui.Say("Mounting the root device...")
 	stderr := new(bytes.Buffer)
-	cmd := exec.Command("mount", device, mountPath)
+	mountCommand := fmt.Sprintf("%s %s %s", config.MountCommand, device, mountPath)
+	cmd := exec.Command("/bin/sh", "-c", mountCommand)
 	cmd.Stderr = stderr
 	if err := cmd.Run(); err != nil {
 		err := fmt.Errorf(
@@ -53,16 +54,12 @@ func (s *StepMountDevice) Cleanup(state map[string]interface{}) {
 		return
 	}
 
+	config := state["config"].(*Config)
 	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)
+	unmountCommand := fmt.Sprintf("%s %s", config.UnmountCommand, s.mountPath)
+	cmd := exec.Command("bin/sh", "-c", unmountCommand)
 	if err := cmd.Run(); err != nil {
 		ui.Error(fmt.Sprintf(
 			"Error unmounting root device: %s", err))