dont use resolveconf on systemd (#70)

* dont use resolveconf on system

* build

* copy resolv conf

* custom handling of resolve conf

* generated code

pkg/builder/builder.go

@@ -36,16 +36,30 @@ var (
 	knownArgs = map[utils.KnownImageType][]string{
 		utils.BeagleBone: {"-cpu", "cortex-a8"},
 	}
-	defaultChrootTypes = [][]string{
+
+	defaultBase = [][]string{
 		{"proc", "proc", "/proc"},
 		{"sysfs", "sysfs", "/sys"},
 		{"bind", "/dev", "/dev"},
 		{"devpts", "devpts", "/dev/pts"},
 		{"binfmt_misc", "binfmt_misc", "/proc/sys/fs/binfmt_misc"},
-		{"bind", "/etc/resolv.conf", "/etc/resolv.conf"},
+	}
+	resolvConfBindMount = []string{"bind", "/etc/resolv.conf", "/etc/resolv.conf"}
+
+	defaultChrootTypes = map[utils.KnownImageType][][]string{
+		utils.Unknown: defaultBase,
 	}
 )
 
+type ResolvConfBehavior string
+
+const (
+	Off      ResolvConfBehavior = "off"
+	CopyHost ResolvConfBehavior = "copy-host"
+	BindHost ResolvConfBehavior = "bind-host"
+	Delete   ResolvConfBehavior = "delete"
+)
+
 type Config struct {
 	packer_common.PackerConfig `mapstructure:",squash"`
 	// While arm image are not ISOs, we resuse the ISO logic as it basically has no ISO specific code.
@@ -88,6 +102,9 @@ type Config struct {
 	// for example: `["bind", "/run/systemd", "/run/systemd"]`
 	AdditionalChrootMounts [][]string `mapstructure:"additional_chroot_mounts"`
 
+	// Can be one of: off, copy-host, bind-host, delete. Defaults to off
+	ResolvConf ResolvConfBehavior `mapstructure:"resolv-conf"`
+
 	// Should the last partition be extended? this only works for the last partition in the
 	// dos partition table, and ext filesystem
 	LastPartitionExtraSize uint64 `mapstructure:"last_partition_extra_size"`
@@ -157,13 +174,20 @@ func (b *Builder) Prepare(cfgs ...interface{}) ([]string, []string, error) {
 	}
 
 	if len(b.config.ChrootMounts) == 0 {
-		b.config.ChrootMounts = defaultChrootTypes
+		b.config.ChrootMounts = defaultChrootTypes[utils.Unknown]
+		if imageDefaults, ok := defaultChrootTypes[b.config.ImageType]; ok {
+			b.config.ChrootMounts = imageDefaults
+		}
 	}
 
 	if len(b.config.AdditionalChrootMounts) > 0 {
 		b.config.ChrootMounts = append(b.config.ChrootMounts, b.config.AdditionalChrootMounts...)
 	}
 
+	if b.config.ResolvConf == BindHost {
+		b.config.ChrootMounts = append(b.config.ChrootMounts, resolvConfBindMount)
+	}
+
 	if b.config.CommandWrapper == "" {
 		b.config.CommandWrapper = "{{.Command}}"
 	}
@@ -233,7 +257,7 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 	state.Put("ui", ui)
 	state.Put("wrappedCommand", packer_common.CommandWrapper(wrappedCommand))
 
-	// HACK: go-getter automatically decompreses, which hurts caching.
+	// HACK: go-getter automatically decompress, which hurts caching.
 	// additionally, we use native binaries to decompress which is faster anyway.
 	// disable decompressors:
 	getter.Decompressors = make(map[string]getter.Decompressor)
@@ -271,6 +295,11 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 		&StepMountExtra{ChrootKey: "mount_path"},
 	)
 
+	if b.config.ResolvConf == CopyHost || b.config.ResolvConf == Delete {
+		steps = append(steps,
+			&stepHandleResolvConf{ChrootKey: "mount_path", Delete: b.config.ResolvConf == Delete})
+	}
+
 	native := runtime.GOARCH == "arm" || runtime.GOARCH == "arm64"
 	if !native {
 		steps = append(steps,

pkg/builder/step_handle_resolv_conf.go

@@ -0,0 +1,61 @@
+package builder
+
+// taken from here: https://github.com/hashicorp/packer/blob/81522dced0b25084a824e79efda02483b12dc7cd/builder/amazon/chroot/step_chroot_provision.go
+
+import (
+	"context"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/hashicorp/packer/helper/multistep"
+	"github.com/hashicorp/packer/packer"
+)
+
+// stepHandleResolvConf provisions the instance within a chroot.
+type stepHandleResolvConf struct {
+	ChrootKey string
+	Delete    bool
+}
+
+func (s *stepHandleResolvConf) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
+	mountPath := state.Get(s.ChrootKey).(string)
+	ui := state.Get("ui").(packer.Ui)
+
+	const origResolvConf = "/etc/resolv.conf"
+	destResolvConf := filepath.Join(mountPath, origResolvConf)
+
+	if s.Delete {
+		err := os.Remove(destResolvConf)
+		if err != nil {
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
+	} else {
+		// copy file over:
+		err := copyFile(destResolvConf, origResolvConf)
+		if err != nil {
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
+	}
+
+	return multistep.ActionContinue
+}
+
+func (s *stepHandleResolvConf) Cleanup(state multistep.StateBag) {}
+
+func copyFile(dst, src string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+	_, err = io.Copy(out, in)
+	return err
+}

pkg/image/utils/images.go

@@ -12,6 +12,7 @@ const (
 	RaspberryPi KnownImageType = "raspberrypi"
 	BeagleBone  KnownImageType = "beaglebone"
 	Kali        KnownImageType = "kali"
+	Unknown     KnownImageType = ""
 )
 
 func GuessImageType(url string) KnownImageType {