packer-cn/packer-plugin-sdk/adapter/scp.go

350 lines
8.1 KiB
Go

package adapter
import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"log"
"os"
"path/filepath"
"strings"
"time"
packersdk "github.com/hashicorp/packer/packer-plugin-sdk/packer"
"github.com/hashicorp/packer/packer-plugin-sdk/tmp"
)
const (
scpOK = "\x00"
scpEmptyError = "\x02\n"
)
/*
scp is a simple, but poorly documented, protocol. Thankfully, its source is
freely available, and there is at least one page that describes it reasonably
well.
* https://raw.githubusercontent.com/openssh/openssh-portable/master/scp.c
* https://opensource.apple.com/source/OpenSSH/OpenSSH-7.1/openssh/scp.c
* https://blogs.oracle.com/janp/entry/how_the_scp_protocol_works is a great
resource, but has some bad information. Its first problem is that it doesn't
correctly describe why the producer has to read more responses than messages
it sends (because it has to read the 0 sent by the sink to start the
transfer). The second problem is that it omits that the producer needs to
send a 0 byte after file contents.
*/
func scpUploadSession(opts []byte, rest string, in io.Reader, out io.Writer, comm packersdk.Communicator) error {
rest = strings.TrimSpace(rest)
if len(rest) == 0 {
fmt.Fprintf(out, scpEmptyError)
return errors.New("no scp target specified")
}
d, err := tmp.Dir("ansible-upload")
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
defer os.RemoveAll(d)
// To properly implement scp, rest should be checked to see if it is a
// directory on the remote side, but ansible only sends files, so there's no
// need to set targetIsDir, because it can be safely assumed that rest is
// intended to be a file, and whatever names are used in 'C' commands are
// irrelevant.
state := &scpUploadState{target: rest, srcRoot: d, comm: comm}
fmt.Fprintf(out, scpOK) // signal the client to start the transfer.
return state.Protocol(bufio.NewReader(in), out)
}
func scpDownloadSession(opts []byte, rest string, in io.Reader, out io.Writer, comm packersdk.Communicator) error {
rest = strings.TrimSpace(rest)
if len(rest) == 0 {
fmt.Fprintf(out, scpEmptyError)
return errors.New("no scp source specified")
}
d, err := tmp.Dir("ansible-download")
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
defer os.RemoveAll(d)
if bytes.Contains([]byte{'d'}, opts) {
// the only ansible module that supports downloading via scp is fetch,
// fetch only supports file downloads as of Ansible 2.1.
fmt.Fprintf(out, scpEmptyError)
return errors.New("directory downloads not supported")
}
f, err := os.Create(filepath.Join(d, filepath.Base(rest)))
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
defer f.Close()
err = comm.Download(rest, f)
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
state := &scpDownloadState{srcRoot: d}
return state.Protocol(bufio.NewReader(in), out)
}
func (state *scpDownloadState) FileProtocol(path string, info os.FileInfo, in *bufio.Reader, out io.Writer) error {
size := info.Size()
perms := fmt.Sprintf("C%04o", info.Mode().Perm())
fmt.Fprintln(out, perms, size, info.Name())
if err := scpResponse(in); err != nil {
return err
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
io.CopyN(out, f, size)
fmt.Fprintf(out, scpOK)
return scpResponse(in)
}
type scpUploadState struct {
comm packersdk.Communicator
target string // target is the directory on the target
srcRoot string // srcRoot is the directory on the host
mtime time.Time
atime time.Time
dir string // dir is a path relative to the roots
targetIsDir bool
}
func (scp scpUploadState) DestPath() string {
return filepath.Join(scp.target, scp.dir)
}
func (scp scpUploadState) SrcPath() string {
return filepath.Join(scp.srcRoot, scp.dir)
}
func (state *scpUploadState) Protocol(in *bufio.Reader, out io.Writer) error {
for {
b, err := in.ReadByte()
if err != nil {
return err
}
switch b {
case 'T':
err := state.TimeProtocol(in, out)
if err != nil {
return err
}
case 'C':
return state.FileProtocol(in, out)
case 'E':
state.dir = filepath.Dir(state.dir)
fmt.Fprintf(out, scpOK)
return nil
case 'D':
return state.DirProtocol(in, out)
default:
fmt.Fprintf(out, scpEmptyError)
return fmt.Errorf("unexpected message: %c", b)
}
}
}
func (state *scpUploadState) FileProtocol(in *bufio.Reader, out io.Writer) error {
defer func() {
state.mtime = time.Time{}
}()
var mode os.FileMode
var size int64
var name string
_, err := fmt.Fscanf(in, "%04o %d %s\n", &mode, &size, &name)
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return fmt.Errorf("invalid file message: %v", err)
}
fmt.Fprintf(out, scpOK)
var fi os.FileInfo = fileInfo{name: name, size: size, mode: mode, mtime: state.mtime}
dest := state.DestPath()
if state.targetIsDir {
dest = filepath.Join(dest, fi.Name())
}
err = state.comm.Upload(dest, io.LimitReader(in, fi.Size()), &fi)
if err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
if err := scpResponse(in); err != nil {
return err
}
fmt.Fprintf(out, scpOK)
return nil
}
func (state *scpUploadState) TimeProtocol(in *bufio.Reader, out io.Writer) error {
var m, a int64
if _, err := fmt.Fscanf(in, "%d 0 %d 0\n", &m, &a); err != nil {
fmt.Fprintf(out, scpEmptyError)
return err
}
fmt.Fprintf(out, scpOK)
state.atime = time.Unix(a, 0)
state.mtime = time.Unix(m, 0)
return nil
}
func (state *scpUploadState) DirProtocol(in *bufio.Reader, out io.Writer) error {
var mode os.FileMode
var length uint
var name string
if _, err := fmt.Fscanf(in, "%04o %d %s\n", &mode, &length, &name); err != nil {
fmt.Fprintf(out, scpEmptyError)
return fmt.Errorf("invalid directory message: %v", err)
}
fmt.Fprintf(out, scpOK)
path := filepath.Join(state.dir, name)
if err := os.Mkdir(path, mode); err != nil {
return err
}
state.dir = path
if state.atime.IsZero() {
state.atime = time.Now()
}
if state.mtime.IsZero() {
state.mtime = time.Now()
}
if err := os.Chtimes(path, state.atime, state.mtime); err != nil {
return err
}
if err := state.comm.UploadDir(filepath.Dir(state.DestPath()), state.SrcPath(), nil); err != nil {
return err
}
state.mtime = time.Time{}
state.atime = time.Time{}
return state.Protocol(in, out)
}
type scpDownloadState struct {
srcRoot string // srcRoot is the directory on the host
}
func (state *scpDownloadState) Protocol(in *bufio.Reader, out io.Writer) error {
r := bufio.NewReader(in)
// read the byte sent by the other side to start the transfer
if err := scpResponse(r); err != nil {
return err
}
return filepath.Walk(state.srcRoot, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if path == state.srcRoot {
return nil
}
if info.IsDir() {
// no need to get fancy; srcRoot should only contain one file, because
// Ansible only allows fetching a single file.
return errors.New("unexpected directory")
}
return state.FileProtocol(path, info, r, out)
})
}
func scpOptions(s string) (opts []byte, rest string) {
end := 0
opt := false
Loop:
for i := 0; i < len(s); i++ {
b := s[i]
switch {
case b == ' ':
opt = false
end++
case b == '-':
opt = true
end++
case opt:
opts = append(opts, b)
end++
default:
break Loop
}
}
rest = s[end:]
return
}
func scpResponse(r *bufio.Reader) error {
code, err := r.ReadByte()
if err != nil {
return err
}
if code != 0 {
message, err := r.ReadString('\n')
if err != nil {
return fmt.Errorf("Error reading error message: %s", err)
}
// 1 is a warning. Anything higher (really just 2) is an error.
if code > 1 {
return errors.New(message)
}
log.Println("WARNING:", err)
}
return nil
}
type fileInfo struct {
name string
size int64
mode os.FileMode
mtime time.Time
}
func (fi fileInfo) Name() string { return fi.name }
func (fi fileInfo) Size() int64 { return fi.size }
func (fi fileInfo) Mode() os.FileMode { return fi.mode }
func (fi fileInfo) ModTime() time.Time {
if fi.mtime.IsZero() {
return time.Now()
}
return fi.mtime
}
func (fi fileInfo) IsDir() bool { return fi.mode.IsDir() }
func (fi fileInfo) Sys() interface{} { return nil }