chore: bootloader abtraction

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

.gitignore

@@ -11,6 +11,8 @@ dist/
 images
 /d2vm
 /examples/build
+/examples/full/demo-magic
+/examples/full/inside
 .goreleaser.yaml
 docs/build
 docs-src

Makefile

@@ -87,7 +87,7 @@ install: docker-build
 
 .build:
 	@go generate ./...
-	@go build -o d2vm -ldflags "-s -w -X '$(MODULE).Version=$(VERSION)' -X '$(MODULE).BuildDate=$(shell date)'" ./cmd/d2vm
+	@CGO_ENABLED=0 go build -o d2vm -ldflags "-s -w -X '$(MODULE).Version=$(VERSION)' -X '$(MODULE).BuildDate=$(shell date)'" ./cmd/d2vm
 
 .PHONY: build-snapshot
 build-snapshot: bin
@@ -116,7 +116,7 @@ completions: .build
 .PHONY: examples
 examples: build-dev
 	@mkdir -p examples/build
-	@for f in $$(find examples -type f -name '*Dockerfile' -maxdepth 1); do \
+	@for f in $$(find examples -maxdepth 1 -type f -name '*Dockerfile'); do \
   		echo "Building $$f"; \
   		./d2vm build -o examples/build/$$(basename $$f|cut -d'.' -f1).qcow2 -p root -f $$f examples --force; \
 	  done

bootloader.go

@@ -0,0 +1,42 @@
+// Copyright 2023 Linka Cloud  All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package d2vm
+
+import (
+	"context"
+	"fmt"
+)
+
+var bootloaderProviders = map[string]BootloaderProvider{}
+
+func RegisterBootloaderProvider(provider BootloaderProvider) {
+	bootloaderProviders[provider.Name()] = provider
+}
+
+func BootloaderByName(name string) (BootloaderProvider, error) {
+	if p, ok := bootloaderProviders[name]; ok {
+		return p, nil
+	}
+	return nil, fmt.Errorf("bootloader provider %s not found", name)
+}
+
+type BootloaderProvider interface {
+	New(c Config) (Bootloader, error)
+	Name() string
+}
+
+type Bootloader interface {
+	Setup(ctx context.Context, raw, path, cmdline string) error
+}

builder.go

@@ -41,72 +41,10 @@ ff02::1 ip6-allnodes
 ff02::2 ip6-allrouters
 ff02::3 ip6-allhosts
 `
-	syslinuxCfgUbuntu = `DEFAULT linux
-  SAY Now booting the kernel from SYSLINUX...
- LABEL linux
-  KERNEL /boot/vmlinuz
-  APPEND ro root=UUID=%s initrd=/boot/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8 %s
-`
-	syslinuxCfgDebian = `DEFAULT linux
-  SAY Now booting the kernel from SYSLINUX...
- LABEL linux
-  KERNEL /vmlinuz
-  APPEND ro root=UUID=%s initrd=/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8 %s
-`
-	syslinuxCfgAlpine = `DEFAULT linux
-  SAY Now booting the kernel from SYSLINUX...
- LABEL linux
-  KERNEL /boot/vmlinuz-virt
-  APPEND ro root=UUID=%s rootfstype=ext4 initrd=/boot/initramfs-virt console=ttyS0,115200 %s
-`
-	syslinuxCfgCentOS = `DEFAULT linux
-  SAY Now booting the kernel from SYSLINUX...
- LABEL linux
-  KERNEL /boot/vmlinuz
-  APPEND ro root=UUID=%s initrd=/boot/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8 %s
-`
-)
-
-var (
-	formats = []string{"qcow2", "qed", "raw", "vdi", "vhd", "vmdk"}
-
-	mbrPaths = []string{
-		// debian path
-		"/usr/lib/syslinux/mbr/mbr.bin",
-		// ubuntu path
-		"/usr/lib/EXTLINUX/mbr.bin",
-		// alpine path
-		"/usr/share/syslinux/mbr.bin",
-		// centos path
-		"/usr/share/syslinux/mbr.bin",
-		// archlinux path
-		"/usr/lib/syslinux/bios/mbr.bin",
-	}
-)
-
-const (
 	perm os.FileMode = 0644
 )
 
-func sysconfig(osRelease OSRelease) (string, error) {
+var formats = []string{"qcow2", "qed", "raw", "vdi", "vhd", "vmdk"}
-	switch osRelease.ID {
-	case ReleaseUbuntu:
-		if osRelease.VersionID < "20.04" {
-			return syslinuxCfgDebian, nil
-		}
-		return syslinuxCfgUbuntu, nil
-	case ReleaseDebian:
-		return syslinuxCfgDebian, nil
-	case ReleaseKali:
-		return syslinuxCfgDebian, nil
-	case ReleaseAlpine:
-		return syslinuxCfgAlpine, nil
-	case ReleaseCentOS:
-		return syslinuxCfgCentOS, nil
-	default:
-		return "", fmt.Errorf("%s: distribution not supported", osRelease.ID)
-	}
-}
 
 type Builder interface {
 	Build(ctx context.Context) (err error)
@@ -115,6 +53,8 @@ type Builder interface {
 
 type builder struct {
 	osRelease  OSRelease
+	config     Config
+	bootloader Bootloader
 
 	src     string
 	img     *image
@@ -128,8 +68,6 @@ type builder struct {
 	splitBoot bool
 	bootSize  uint64
 
-	mbrPath string
-
 	loDevice        string
 	bootPart        string
 	rootPart        string
@@ -145,7 +83,7 @@ type builder struct {
 	cmdLineExtra string
 }
 
-func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64, osRelease OSRelease, format string, cmdLineExtra string, splitBoot bool, bootSize uint64, luksPassword string) (Builder, error) {
+func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64, osRelease OSRelease, format string, cmdLineExtra string, splitBoot bool, bootSize uint64, luksPassword string, bootLoader string) (Builder, error) {
 	if err := checkDependencies(); err != nil {
 		return nil, err
 	}
@@ -176,16 +114,24 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 		return nil, fmt.Errorf("boot partition size must be less than the disk size")
 	}
 
-	mbrBin := ""
+	if bootLoader == "" {
-	for _, v := range mbrPaths {
+		bootLoader = "syslinux"
-		if _, err := os.Stat(v); err == nil {
-			mbrBin = v
-			break
 	}
+
+	config, err := osRelease.Config()
+	if err != nil {
+		return nil, err
 	}
-	if mbrBin == "" {
+
-		return nil, fmt.Errorf("unable to find syslinux's mbr.bin path")
+	blp, err := BootloaderByName(bootLoader)
+	if err != nil {
+		return nil, err
 	}
+	bl, err := blp.New(config)
+	if err != nil {
+		return nil, err
+	}
+
 	if size == 0 {
 		size = 10 * uint64(datasize.GB)
 	}
@@ -207,12 +153,13 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 	// }
 	b := &builder{
 		osRelease:    osRelease,
+		config:       config,
+		bootloader:   bl,
 		img:          img,
 		diskRaw:      filepath.Join(workdir, disk+".d2vm.raw"),
 		diskOut:      filepath.Join(workdir, disk+"."+format),
 		format:       f,
 		size:         size,
-		mbrPath:      mbrBin,
 		mntPoint:     filepath.Join(workdir, "/mnt"),
 		cmdLineExtra: cmdLineExtra,
 		splitBoot:    splitBoot,
@@ -259,9 +206,6 @@ func (b *builder) Build(ctx context.Context) (err error) {
 	if err = b.unmountImg(ctx); err != nil {
 		return err
 	}
-	if err = b.setupMBR(ctx); err != nil {
-		return err
-	}
 	if err = b.convert2Img(ctx); err != nil {
 		return err
 	}
@@ -490,45 +434,27 @@ func (b *builder) setupRootFS(ctx context.Context) (err error) {
 	}
 }
 
-func (b *builder) installKernel(ctx context.Context) error {
+func (b *builder) cmdline(_ context.Context) string {
-	logrus.Infof("installing linux kernel")
-	if err := exec.Run(ctx, "extlinux", "--install", b.chPath("/boot")); err != nil {
-		return err
-	}
-	sysconfig, err := sysconfig(b.osRelease)
-	if err != nil {
-		return err
-	}
-	var cfg string
 	if b.isLuksEnabled() {
 		switch b.osRelease.ID {
 		case ReleaseAlpine:
-			cfg = fmt.Sprintf(sysconfig, b.rootUUID, fmt.Sprintf("%s root=/dev/mapper/root cryptdm=root", b.cmdLineExtra))
+			return b.config.Cmdline(RootUUID(b.rootUUID), "root=/dev/mapper/root", "cryptdm=root", "cryptroot=UUID="+b.cryptUUID, b.cmdLineExtra)
-			cfg = strings.Replace(cfg, "root=UUID="+b.rootUUID, "cryptroot=UUID="+b.cryptUUID, 1)
 		case ReleaseCentOS:
-			cfg = fmt.Sprintf(sysconfig, b.rootUUID, fmt.Sprintf("%s rd.luks.name=UUID=%s rd.luks.uuid=%s rd.luks.crypttab=0", b.cmdLineExtra, b.rootUUID, b.cryptUUID))
+			return b.config.Cmdline(RootUUID(b.rootUUID), "rd.luks.name=UUID="+b.rootUUID+" rd.luks.uuid="+b.cryptUUID+" rd.luks.crypttab=0", b.cmdLineExtra)
 		default:
 			// for some versions of debian, the cryptopts parameter MUST contain all the following: target,source,key,opts...
 			// see https://salsa.debian.org/cryptsetup-team/cryptsetup/-/blob/debian/buster/debian/functions
 			// and https://cryptsetup-team.pages.debian.net/cryptsetup/README.initramfs.html
-			cfg = fmt.Sprintf(sysconfig, b.rootUUID, fmt.Sprintf("%s root=/dev/mapper/root cryptopts=target=root,source=UUID=%s,key=none,luks", b.cmdLineExtra, b.cryptUUID))
+			return b.config.Cmdline(nil, "root=/dev/mapper/root", "cryptopts=target=root,source=UUID="+b.cryptUUID+",key=none,luks", b.cmdLineExtra)
-			cfg = strings.Replace(cfg, "root=UUID="+b.rootUUID, "", 1)
 		}
 	} else {
-		cfg = fmt.Sprintf(sysconfig, b.rootUUID, b.cmdLineExtra)
+		return b.config.Cmdline(RootUUID(b.rootUUID), b.cmdLineExtra)
 	}
-	if err := b.chWriteFile("/boot/syslinux.cfg", cfg, perm); err != nil {
-		return err
-	}
-	return nil
 }
 
-func (b *builder) setupMBR(ctx context.Context) error {
+func (b *builder) installKernel(ctx context.Context) error {
-	logrus.Infof("writing MBR")
+	logrus.Infof("installing linux kernel")
-	if err := exec.Run(ctx, "dd", fmt.Sprintf("if=%s", b.mbrPath), fmt.Sprintf("of=%s", b.diskRaw), "bs=440", "count=1", "conv=notrunc"); err != nil {
+	return b.bootloader.Setup(ctx, b.diskRaw, b.chPath("/boot"), b.cmdline(ctx))
-		return err
-	}
-	return nil
 }
 
 func (b *builder) convert2Img(ctx context.Context) error {

config.go

@@ -0,0 +1,89 @@
+// Copyright 2023 Linka Cloud  All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package d2vm
+
+import (
+	"fmt"
+	"strings"
+)
+
+var (
+	configUbuntu = Config{
+		Kernel: "/boot/vmlinuz",
+		Initrd: "/boot/initrd.img",
+	}
+	configDebian = Config{
+		Kernel: "/vmlinuz",
+		Initrd: "/initrd.img",
+	}
+	configAlpine = Config{
+		Kernel: "/boot/vmlinuz-virt",
+		Initrd: "/boot/initramfs-virt",
+	}
+	configCentOS = Config{
+		Kernel: "/boot/vmlinuz",
+		Initrd: "/boot/initrd.img",
+	}
+)
+
+type Root interface {
+	String() string
+}
+
+type RootUUID string
+
+func (r RootUUID) String() string {
+	return "UUID=" + string(r)
+}
+
+type RootPath string
+
+func (r RootPath) String() string {
+	return string(r)
+}
+
+type Config struct {
+	Kernel string
+	Initrd string
+}
+
+func (c Config) Cmdline(root Root, args ...string) string {
+	var r string
+	if root != nil {
+		r = fmt.Sprintf("root=%s", root.String())
+	}
+	return fmt.Sprintf("ro initrd=%s %s net.ifnames=0 rootfstype=ext4 console=tty0 console=ttyS0,115200n8 %s", c.Initrd, r, strings.Join(args, " "))
+}
+
+func (r OSRelease) Config() (Config, error) {
+	switch r.ID {
+	case ReleaseUbuntu:
+		if r.VersionID < "20.04" {
+			return configDebian, nil
+		}
+		return configUbuntu, nil
+	case ReleaseDebian:
+		return configDebian, nil
+	case ReleaseKali:
+		return configDebian, nil
+	case ReleaseAlpine:
+		return configAlpine, nil
+	case ReleaseCentOS:
+		return configCentOS, nil
+	default:
+		return Config{}, fmt.Errorf("%s: distribution not supported", r.ID)
+
+	}
+}

config_test.go

@@ -23,14 +23,13 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/sirupsen/logrus"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"go.linka.cloud/d2vm/pkg/docker"
 	"go.linka.cloud/d2vm/pkg/exec"
 )
 
-func testSysconfig(t *testing.T, ctx context.Context, img, sysconf, kernel, initrd string) {
+func testConfig(t *testing.T, ctx context.Context, img string, config Config) {
 	require.NoError(t, docker.Pull(ctx, img))
 	tmpPath := filepath.Join(os.TempDir(), "d2vm-tests", strings.NewReplacer(":", "-", ".", "-").Replace(img))
 	require.NoError(t, os.MkdirAll(tmpPath, 0755))
@@ -39,9 +38,6 @@ func testSysconfig(t *testing.T, ctx context.Context, img, sysconf, kernel, init
 	r, err := FetchDockerImageOSRelease(ctx, img, tmpPath)
 	require.NoError(t, err)
 	defer docker.Remove(ctx, img)
-	sys, err := sysconfig(r)
-	require.NoError(t, err)
-	assert.Equal(t, sysconf, sys)
 	d, err := NewDockerfile(r, img, "root", "", false)
 	require.NoError(t, err)
 	logrus.Infof("docker image based on %s", d.Release.Name)
@@ -55,95 +51,67 @@ func testSysconfig(t *testing.T, ctx context.Context, img, sysconf, kernel, init
 	logrus.Infof("building kernel enabled image")
 	require.NoError(t, docker.Build(ctx, imgUUID, p, dir))
 	defer docker.Remove(ctx, imgUUID)
-	require.NoError(t, docker.RunAndRemove(ctx, imgUUID, "test", "-f", kernel))
+	require.NoError(t, docker.RunAndRemove(ctx, imgUUID, "test", "-f", config.Kernel))
-	require.NoError(t, docker.RunAndRemove(ctx, imgUUID, "test", "-f", initrd))
+	require.NoError(t, docker.RunAndRemove(ctx, imgUUID, "test", "-f", config.Initrd))
 }
 
-func TestSyslinuxCfg(t *testing.T) {
+func TestConfig(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		image  string
-		kernel    string
+		config Config
-		initrd    string
-		sysconfig string
 	}{
 		{
 			image:  "ubuntu:18.04",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "ubuntu:20.04",
-			kernel:    "/boot/vmlinuz",
+			config: configUbuntu,
-			initrd:    "/boot/initrd.img",
-			sysconfig: syslinuxCfgUbuntu,
 		},
 		{
 			image:  "ubuntu:22.04",
-			kernel:    "/boot/vmlinuz",
+			config: configUbuntu,
-			initrd:    "/boot/initrd.img",
-			sysconfig: syslinuxCfgUbuntu,
 		},
 		{
 			image:  "ubuntu:latest",
-			kernel:    "/boot/vmlinuz",
+			config: configUbuntu,
-			initrd:    "/boot/initrd.img",
-			sysconfig: syslinuxCfgUbuntu,
 		},
 		{
 			image:  "debian:9",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "debian:10",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "debian:11",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "debian:latest",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "kalilinux/kali-rolling:latest",
-			kernel:    "/vmlinuz",
+			config: configDebian,
-			initrd:    "/initrd.img",
-			sysconfig: syslinuxCfgDebian,
 		},
 		{
 			image:  "alpine:3.16",
-			kernel:    "/boot/vmlinuz-virt",
+			config: configAlpine,
-			initrd:    "/boot/initramfs-virt",
-			sysconfig: syslinuxCfgAlpine,
 		},
 		{
 			image:  "alpine",
-			kernel:    "/boot/vmlinuz-virt",
+			config: configAlpine,
-			initrd:    "/boot/initramfs-virt",
-			sysconfig: syslinuxCfgAlpine,
 		},
 		{
 			image:  "centos:8",
-			kernel:    "/boot/vmlinuz",
+			config: configCentOS,
-			initrd:    "/boot/initrd.img",
-			sysconfig: syslinuxCfgCentOS,
 		},
 		{
 			image:  "centos:latest",
-			kernel:    "/boot/vmlinuz",
+			config: configCentOS,
-			initrd:    "/boot/initrd.img",
-			sysconfig: syslinuxCfgCentOS,
 		},
 	}
 	exec.SetDebug(true)
@@ -154,7 +122,7 @@ func TestSyslinuxCfg(t *testing.T) {
 			t.Parallel()
 			ctx, cancel := context.WithCancel(context.Background())
 			defer cancel()
-			testSysconfig(t, ctx, test.image, test.sysconfig, test.kernel, test.initrd)
+			testConfig(t, ctx, test.image, test.config)
 		})
 	}
 }

convert.go

@@ -88,7 +88,7 @@ func Convert(ctx context.Context, img string, opts ...ConvertOption) error {
 	if format == "" {
 		format = "raw"
 	}
-	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", o.size, r, format, o.cmdLineExtra, o.splitBoot, o.bootSize, o.luksPassword)
+	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", o.size, r, format, o.cmdLineExtra, o.splitBoot, o.bootSize, o.luksPassword, "")
 	if err != nil {
 		return err
 	}

syslinux.go

@@ -0,0 +1,92 @@
+// Copyright 2023 Linka Cloud  All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package d2vm
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/sirupsen/logrus"
+
+	"go.linka.cloud/d2vm/pkg/exec"
+)
+
+const syslinuxCfg = `DEFAULT linux
+  SAY Now booting the kernel from SYSLINUX...
+ LABEL linux
+  KERNEL %s
+  APPEND %s
+`
+
+var mbrPaths = []string{
+	// debian path
+	"/usr/lib/syslinux/mbr/mbr.bin",
+	// ubuntu path
+	"/usr/lib/EXTLINUX/mbr.bin",
+	// alpine path
+	"/usr/share/syslinux/mbr.bin",
+	// centos path
+	"/usr/share/syslinux/mbr.bin",
+	// archlinux path
+	"/usr/lib/syslinux/bios/mbr.bin",
+}
+
+type syslinux struct {
+	c      Config
+	mbrBin string
+}
+
+func (s syslinux) Setup(ctx context.Context, raw, path string, cmdline string) error {
+	if err := exec.Run(ctx, "extlinux", "--install", path); err != nil {
+		return err
+	}
+	if err := os.WriteFile(filepath.Join(path, "syslinux.cfg"), []byte(fmt.Sprintf(syslinuxCfg, s.c.Kernel, cmdline)), perm); err != nil {
+		return err
+	}
+	logrus.Infof("writing MBR")
+	if err := exec.Run(ctx, "dd", fmt.Sprintf("if=%s", s.mbrBin), fmt.Sprintf("of=%s", raw), "bs=440", "count=1", "conv=notrunc"); err != nil {
+		return err
+	}
+	return nil
+}
+
+type syslinuxProvider struct{}
+
+func (s syslinuxProvider) New(c Config) (Bootloader, error) {
+	mbrBin := ""
+	for _, v := range mbrPaths {
+		if _, err := os.Stat(v); err == nil {
+			mbrBin = v
+			break
+		}
+	}
+	if mbrBin == "" {
+		return nil, fmt.Errorf("unable to find syslinux's mbr.bin path")
+	}
+	return &syslinux{
+		c:      c,
+		mbrBin: mbrBin,
+	}, nil
+}
+
+func (s syslinuxProvider) Name() string {
+	return "syslinux"
+}
+
+func init() {
+	RegisterBootloaderProvider(syslinuxProvider{})
+}