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//
// Helpers to work with an Ubuntu image based Upgrade implementation
//
// Copyright (c) 2013 Canonical Ltd.
//
// Written by Sergio Schvezov <sergio.schvezov@canonical.com>
//
package ubuntuimage
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License version 3, as published
// by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranties of
// MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
// PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see <http://www.gnu.org/licenses/>.
import (
"bufio"
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"io"
"io/ioutil"
"net/url"
"os"
"path/filepath"
"syscall"
"github.com/cheggaaa/pb"
)
func hashMatches(filePath, hash string) bool {
h := sha256.New()
var err error
fileBytes, err := ioutil.ReadFile(filePath)
if err != nil {
return false
}
h.Write(fileBytes)
hashString := hex.EncodeToString(h.Sum(nil))
if hashString == hash {
return true
}
return false
}
const commandsStart = `format system
load_keyring image-master.tar.xz image-master.tar.xz.asc
load_keyring image-signing.tar.xz image-signing.tar.xz.asc
mount system
`
func GetUbuntuCommands(files []File, downloadDir string, wipe bool, enable []string) (commandsFile string, err error) {
tmpFile, err := ioutil.TempFile(downloadDir, "ubuntu_commands")
if err != nil {
return commandsFile, err
}
writer := bufio.NewWriter(tmpFile)
defer func() {
if err == nil {
writer.Flush()
}
}()
if wipe {
writer.WriteString("format data\n")
}
if files != nil {
writer.WriteString(commandsStart)
order := func(f1, f2 *File) bool {
return f1.Order < f2.Order
}
By(order).Sort(files)
for _, file := range files {
writer.WriteString(
fmt.Sprintf("update %s %s\n", filepath.Base(file.Path), filepath.Base(file.Signature)))
}
}
//we cannot enable "things" outside of userdata
for i := range enable {
writer.WriteString(fmt.Sprintf("enable %s\n", enable[i]))
}
writer.WriteString("unmount system\n")
return tmpFile.Name(), err
}
func GetGPGFiles() []File {
return []File{{Path: "/gpg/image-master.tar.xz", Signature: "/gpg/image-master.tar.xz.asc"},
{Path: "/gpg/image-signing.tar.xz", Signature: "/gpg/image-signing.tar.xz.asc"}}
}
func getLockFd(file string) (fileLock *os.File, err error) {
err = os.MkdirAll(filepath.Dir(file), 0700)
if err != nil {
return nil, err
}
fileLock, err = os.Create(file + "_lock")
if err != nil {
return nil, err
}
return fileLock, nil
}
//MakeRelativeToServer changes absolute paths in Path into a relative path and adds the host
//part to Server, if the Path is already relative it uses defaultServer
func (file *File) MakeRelativeToServer(defaultServer string) error {
file.Server = defaultServer
u, err := url.Parse(file.Path)
if err != nil {
return err
}
if u.IsAbs() {
file.Server = u.Scheme + "://" + u.Host
file.Path = u.Path
file.Signature = file.Path + ".asc"
}
return nil
}
func (file File) Download(downloadDir string) (err error) {
//TODO Verify downloaded gpg agains image
path := filepath.Join(downloadDir, file.Path)
// Create file lock to avoid multiple processes downloading the same file
lock, err := getLockFd(path)
if err != nil {
return err
}
err = syscall.Flock(int(lock.Fd()), syscall.LOCK_EX)
if err != nil {
return err
}
defer func() {
os.Remove(lock.Name())
syscall.Flock(int(lock.Fd()), syscall.LOCK_UN)
}()
if hashMatches(path, file.Checksum) {
return nil
}
for _, f := range []string{file.Signature, file.Path} {
uri := file.Server + f
path := filepath.Join(downloadDir, f)
err := os.MkdirAll(filepath.Dir(path), 0700)
if err != nil {
return err
}
target, err := os.Create(path + "_")
if err != nil {
return err
}
defer func() {
target.Close()
if err == nil {
os.Rename(path+"_", path)
}
}()
err = download(uri, target)
if err != nil {
return err
}
}
return err
}
func download(uri string, writer io.Writer) (err error) {
resp, err := client.Get(uri)
if err != nil {
return err
}
if resp.StatusCode != 200 {
return errors.New(fmt.Sprintf("Got status code %d for %s", resp.StatusCode, uri))
}
defer resp.Body.Close()
// Only display a progress bar for files > 2K in size
// nb, ContentLength is -1 for *.asc files
if resp.ContentLength > 2048 {
pbar := pb.New(int(resp.ContentLength))
pbar.ShowSpeed = true
pbar.Units = pb.U_BYTES
pbar.Start()
mw := io.MultiWriter(writer, pbar)
_, err = io.Copy(mw, resp.Body)
pbar.Finish()
} else {
bufReader := bufio.NewReader(resp.Body)
bufWriter := bufio.NewWriter(writer)
defer func() {
if err == nil {
err = bufWriter.Flush()
}
}()
_, err = bufReader.WriteTo(bufWriter)
}
return err
}
func GetCacheDir() (cacheDir string) {
cacheDir = os.Getenv("XDG_CACHE_HOME")
if cacheDir == "" {
cacheDir = "$HOME/.cache/"
}
cacheDir = os.ExpandEnv(cacheDir)
return filepath.Join(cacheDir, "ubuntuimages")
}
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