mirror of https://github.com/linka-cloud/d2vm.git
339 lines
8.6 KiB
Go
339 lines
8.6 KiB
Go
// Copyright 2022 Linka Cloud All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package docker2vm
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import (
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"bytes"
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"context"
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"fmt"
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"os"
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exec2 "os/exec"
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"path/filepath"
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"strings"
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"github.com/sirupsen/logrus"
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"go.uber.org/multierr"
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"go.linka.cloud/d2vm/pkg/exec"
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)
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const (
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hosts = `127.0.0.1 localhost
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# The following lines are desirable for IPv6 capable hosts
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::1 ip6-localhost ip6-loopback
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fe00::0 ip6-localnet
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ff00::0 ip6-mcastprefix
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ff02::1 ip6-allnodes
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ff02::2 ip6-allrouters
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ff02::3 ip6-allhosts
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`
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syslinuxCfgUbuntu = `DEFAULT linux
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SAY Now booting the kernel from SYSLINUX...
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LABEL linux
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KERNEL /boot/vmlinuz
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APPEND ro root=UUID=%s initrd=/boot/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8
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`
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syslinuxCfgDebian = `DEFAULT linux
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SAY Now booting the kernel from SYSLINUX...
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LABEL linux
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KERNEL /vmlinuz
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APPEND ro root=UUID=%s initrd=/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8
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`
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syslinuxCfgAlpine = `DEFAULT linux
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SAY Now booting the kernel from SYSLINUX...
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LABEL linux
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KERNEL /boot/vmlinuz-virt
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APPEND ro root=UUID=%s rootfstype=ext4 initrd=/boot/initramfs-virt console=ttyS0,115200
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`
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syslinuxCfgCentOS = `DEFAULT linux
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SAY Now booting the kernel from SYSLINUX...
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LABEL linux
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KERNEL /boot/vmlinuz
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APPEND ro root=UUID=%s initrd=/boot/initrd.img net.ifnames=0 console=tty0 console=ttyS0,115200n8
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`
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mbrBin = "/usr/lib/EXTLINUX/mbr.bin"
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)
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var (
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fdiskCmds = []string{"n", "p", "1", "", "", "a", "w"}
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)
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type builder struct {
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osRelease OSRelease
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src string
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diskRaw string
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diskQcow2 string
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size int64
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mntPoint string
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loDevice string
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loPart string
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diskUUD string
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}
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func NewBuilder(workdir, src, disk string, size int64, osRelease OSRelease) (*builder, error) {
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if err := checkDependencies(); err != nil {
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return nil, err
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}
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if size == 0 {
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size = 1
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}
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if disk == "" {
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disk = "disk0"
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}
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b := &builder{
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osRelease: osRelease,
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src: src,
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diskRaw: filepath.Join(workdir, disk+".raw"),
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diskQcow2: filepath.Join(workdir, disk+".qcow2"),
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size: size,
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mntPoint: filepath.Join(workdir, "/mnt"),
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}
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if err := os.MkdirAll(b.mntPoint, os.ModePerm); err != nil {
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return nil, err
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}
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return b, nil
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}
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func (b *builder) Build(ctx context.Context) (err error) {
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defer func() {
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if err == nil {
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return
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}
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logrus.WithError(err).Error("Build failed")
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if err := b.unmountImg(context.Background()); err != nil {
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logrus.WithError(err).Error("failed to unmount")
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}
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if err := b.cleanUp(context.Background()); err != nil {
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logrus.WithError(err).Error("failed to cleanup")
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}
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}()
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if err = b.cleanUp(ctx); err != nil {
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return err
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}
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if err = b.makeImg(ctx); err != nil {
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return err
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}
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if err = b.mountImg(ctx); err != nil {
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return err
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}
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if err = b.copyRootFS(ctx); err != nil {
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return err
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}
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if err = b.setupRootFS(ctx); err != nil {
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return err
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}
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if err = b.installKernel(ctx); err != nil {
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return err
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}
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if err = b.unmountImg(ctx); err != nil {
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return err
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}
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if err = b.setupMBR(ctx); err != nil {
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return err
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}
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if err = b.convert2Qcow2(ctx); err != nil {
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return err
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}
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if err = b.cleanUp(ctx); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) cleanUp(ctx context.Context) error {
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return os.RemoveAll(b.diskRaw)
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}
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func (b *builder) makeImg(ctx context.Context) error {
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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logrus.Infof("creating raw image")
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if err := block(b.diskRaw, b.size); err != nil {
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return err
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}
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c := exec.CommandContext(ctx, "fdisk", b.diskRaw)
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var i bytes.Buffer
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for _, v := range fdiskCmds {
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if _, err := i.Write([]byte(v + "\n")); err != nil {
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return err
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}
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}
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var e bytes.Buffer
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c.Stdin = &i
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c.Stderr = &e
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if err := c.Run(); err != nil {
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return fmt.Errorf("%w: %s", err, e.String())
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}
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return nil
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}
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func (b *builder) mountImg(ctx context.Context) error {
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logrus.Infof("mounting raw image")
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o, _, err := exec.RunOut(ctx, "losetup", "--show", "-f", b.diskRaw)
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if err != nil {
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return err
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}
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b.loDevice = strings.TrimSuffix(o, "\n")
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if err := exec.Run(ctx, "kpartx", "-a", b.loDevice); err != nil {
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return err
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}
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b.loPart = fmt.Sprintf("/dev/mapper/%sp1", filepath.Base(b.loDevice))
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logrus.Infof("creating raw image file system")
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if err := exec.Run(ctx, "mkfs.ext4", b.loPart); err != nil {
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return err
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}
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if err := exec.Run(ctx, "mount", b.loPart, b.mntPoint); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) unmountImg(ctx context.Context) error {
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logrus.Infof("unmounting raw image")
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var merr error
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if err := exec.Run(ctx, "umount", b.mntPoint); err != nil {
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merr = multierr.Append(merr, err)
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}
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if err := exec.Run(ctx, "kpartx", "-d", b.loDevice); err != nil {
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merr = multierr.Append(merr, err)
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}
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if err := exec.Run(ctx, "losetup", "-d", b.loDevice); err != nil {
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merr = multierr.Append(merr, err)
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}
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return merr
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}
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func (b *builder) copyRootFS(ctx context.Context) error {
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logrus.Infof("copying rootfs to raw image")
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if err := exec.Run(ctx, "tar", "-xvf", b.src, "-C", b.mntPoint); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) setupRootFS(ctx context.Context) error {
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logrus.Infof("setting up rootfs")
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o, _, err := exec.RunOut(ctx, "blkid", "-s", "UUID", "-o", "value", b.loPart)
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if err != nil {
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return err
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}
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b.diskUUD = strings.TrimSuffix(o, "\n")
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fstab := fmt.Sprintf("UUID=%s / ext4 errors=remount-ro 0 1\n", b.diskUUD)
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if err := b.chWriteFile("/etc/fstab", fstab, 0644); err != nil {
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return err
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}
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if err := b.chWriteFile("/etc/resolv.conf", "nameserver 8.8.8.8", 0644); err != nil {
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return err
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}
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if err := b.chWriteFile("/etc/hostname", "localhost", 0644); err != nil {
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return err
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}
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if err := b.chWriteFile("/etc/hosts", hosts, 0644); err != nil {
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return err
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}
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if err := os.RemoveAll("/ur/sbin/policy-rc.d"); err != nil {
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return err
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}
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if err := os.RemoveAll(b.chPath("/.dockerenv")); err != nil {
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return err
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}
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if b.osRelease.ID != ReleaseAlpine {
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return nil
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}
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by, err := os.ReadFile(b.chPath("/etc/inittab"))
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if err != nil {
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return err
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}
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by = append(by, []byte("\n"+"ttyS0::respawn:/sbin/getty -L ttyS0 115200 vt100\n")...)
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if err := b.chWriteFile("/etc/inittab", string(by), 0644); err != nil {
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return err
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}
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if err := b.chWriteFile("/etc/network/interfaces", "", 0644); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) installKernel(ctx context.Context) error {
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logrus.Infof("installing linux kernel")
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if err := exec.Run(ctx, "extlinux", "--install", b.chPath("/boot")); err != nil {
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return err
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}
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var sysconfig string
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switch b.osRelease.ID {
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case ReleaseUbuntu:
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sysconfig = syslinuxCfgUbuntu
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case ReleaseDebian:
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sysconfig = syslinuxCfgDebian
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case ReleaseAlpine:
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sysconfig = syslinuxCfgAlpine
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case ReleaseCentOS:
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sysconfig = syslinuxCfgCentOS
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default:
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return fmt.Errorf("%s: distribution not supported", b.osRelease.ID)
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}
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if err := b.chWriteFile("/boot/syslinux.cfg", fmt.Sprintf(sysconfig, b.diskUUD), 0644); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) setupMBR(ctx context.Context) error {
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logrus.Infof("writing MBR")
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if err := exec.Run(ctx, "dd", fmt.Sprintf("if=%s", mbrBin), fmt.Sprintf("of=%s", b.diskRaw), "bs=440", "count=1", "conv=notrunc"); err != nil {
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return err
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}
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return nil
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}
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func (b *builder) convert2Qcow2(ctx context.Context) error {
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logrus.Infof("converting to QCOW2")
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return exec.Run(ctx, "qemu-img", "convert", b.diskRaw, "-O", "qcow2", b.diskQcow2)
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}
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func (b *builder) chWriteFile(path string, content string, perm os.FileMode) error {
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return os.WriteFile(b.chPath(path), []byte(content), perm)
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}
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func (b *builder) chPath(path string) string {
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return fmt.Sprintf("%s%s", b.mntPoint, path)
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}
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func block(path string, size int64) error {
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f, err := os.Create(path)
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if err != nil {
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return err
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}
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defer f.Close()
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return f.Truncate(size)
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}
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func checkDependencies() error {
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var merr error
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for _, v := range []string{"mount", "blkid", "tar", "kpartx", "losetup", "qemu-img", "extlinux", "dd", "mkfs", "fdisk"} {
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if _, err := exec2.LookPath(v); err != nil {
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merr = multierr.Append(merr, err)
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}
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}
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if _, err := os.Stat(mbrBin); err != nil {
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merr = multierr.Append(merr, err)
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}
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return merr
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}
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