chore: bootloader abtraction

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

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{})
+}