tempfork/netshell: delete, use github.com/go4org/plan9netshell instead

Change-Id: I2aee6b55f2084a7c3df0db830b28edd1fba0f528
This commit is contained in:
Brad Fitzpatrick 2025-03-24 11:38:42 -07:00
parent 391edc4712
commit 261776e2e4
4 changed files with 6 additions and 498 deletions

1
go.mod
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@ -37,6 +37,7 @@ require (
github.com/go-json-experiment/json v0.0.0-20250223041408-d3c622f1b874
github.com/go-logr/zapr v1.3.0
github.com/go-ole/go-ole v1.3.0
github.com/go4org/plan9netshell v0.0.0-20250324183649-788daa080737
github.com/godbus/dbus/v5 v5.1.1-0.20230522191255-76236955d466
github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da
github.com/golang/snappy v0.0.4

4
go.sum
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@ -236,8 +236,6 @@ github.com/creachadair/mds v0.17.1/go.mod h1:4b//mUiL8YldH6TImXjmW45myzTLNS1LLjO
github.com/creachadair/taskgroup v0.13.2 h1:3KyqakBuFsm3KkXi/9XIb0QcA8tEzLHLgaoidf0MdVc=
github.com/creachadair/taskgroup v0.13.2/go.mod h1:i3V1Zx7H8RjwljUEeUWYT30Lmb9poewSb2XI1yTwD0g=
github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
github.com/creack/pty v1.1.21 h1:1/QdRyBaHHJP61QkWMXlOIBfsgdDeeKfK8SYVUWJKf0=
github.com/creack/pty v1.1.21/go.mod h1:MOBLtS5ELjhRRrroQr9kyvTxUAFNvYEK993ew/Vr4O4=
github.com/creack/pty v1.1.23 h1:4M6+isWdcStXEf15G/RbrMPOQj1dZ7HPZCGwE4kOeP0=
github.com/creack/pty v1.1.23/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
github.com/curioswitch/go-reassign v0.2.0 h1:G9UZyOcpk/d7Gd6mqYgd8XYWFMw/znxwGDUstnC9DIo=
@ -393,6 +391,8 @@ github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1 h1:TQcrn6Wq+sKGkpyPvppOz99zsM
github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
github.com/go-xmlfmt/xmlfmt v1.1.2 h1:Nea7b4icn8s57fTx1M5AI4qQT5HEM3rVUO8MuE6g80U=
github.com/go-xmlfmt/xmlfmt v1.1.2/go.mod h1:aUCEOzzezBEjDBbFBoSiya/gduyIiWYRP6CnSFIV8AM=
github.com/go4org/plan9netshell v0.0.0-20250324183649-788daa080737 h1:cf60tHxREO3g1nroKr2osU3JWZsJzkfi7rEg+oAB0Lo=
github.com/go4org/plan9netshell v0.0.0-20250324183649-788daa080737/go.mod h1:MIS0jDzbU/vuM9MC4YnBITCv+RYuTRq8dJzmCrFsK9g=
github.com/gobuffalo/flect v1.0.3 h1:xeWBM2nui+qnVvNM4S3foBhCAL2XgPU+a7FdpelbTq4=
github.com/gobuffalo/flect v1.0.3/go.mod h1:A5msMlrHtLqh9umBSnvabjsMrCcCpAyzglnDvkbYKHs=
github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y=

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@ -23,10 +23,10 @@ import (
"strings"
"sync/atomic"
"github.com/go4org/plan9netshell"
"github.com/pkg/sftp"
"tailscale.com/cmd/tailscaled/childproc"
"tailscale.com/tailcfg"
"tailscale.com/tempfork/netshell"
"tailscale.com/types/logger"
)
@ -219,7 +219,7 @@ func (ia incubatorArgs) forwardedEnviron() ([]string, string, error) {
}
func beNetshell(args []string) error {
netshell.Main()
plan9netshell.Main()
return nil
}
@ -249,7 +249,7 @@ func beIncubator(args []string) error {
}
if ia.isShell {
netshell.Main()
plan9netshell.Main()
return nil
}

View File

@ -1,493 +0,0 @@
// Copyright (c) Plan 9 Foundation, Russ Cox, Google LLC, Tailscale Inc, etc.
// SPDX-License-Identifier: BSD-3-Clause
// This file is a fork of github.com/9fans/go (Go module 9fans.net/go)'s
// file ./plan9/srv9p/example/netshell/main.go turned from a package main
// to a non-main package.
//go:build plan9
// Package netshell implements /dev/cons and /dev/consctl using
// stdin and stdout as a source of bytes and runs a login shell
// in a new namespace with /dev/cons opened to it.
//
// For example, the one-line “insecure shell daemon”:
//
// aux/listen1 'tcp!*!22222' netshell
//
// This differs from running rc directly in that it provides
// terminal echo, a /dev/cons file, and mostly standard Plan 9 line editing
// (^C, ^D, ^U, ^W, backspace, and delete).
// Unlike standard Plan 9, ^C sends an interrupt and delete is backspace.
package netshell
import (
"bytes"
"context"
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
"runtime"
"strconv"
"strings"
"sync"
"syscall"
"unicode"
"unicode/utf8"
"9fans.net/go/plan9"
"9fans.net/go/plan9/srv9p"
)
const Env = "_NETSHELL_CHILD_"
var Verbose = os.Getenv("NETSHELL_VERBOSE") == "1"
func init() {
if os.Getenv(Env) != "" {
runtime.LockOSThread() // to keep runChild on main thread
}
}
func Main() {
log.SetFlags(0)
log.SetPrefix("netshell: ")
if os.Getenv(Env) != "" {
runChild()
return
}
c := newConsole(os.Stdin, os.Stdout)
tree := srv9p.NewTree("netshell", "netshell", plan9.DMDIR|0555, nil)
cons, _ := tree.Root.Create("cons", "netshell", 0666, nil)
consctl, _ := tree.Root.Create("consctl", "netshell", 0222, nil)
srv := &srv9p.Server{
Tree: tree,
Read: func(ctx context.Context, fid *srv9p.Fid, data []byte, offset int64) (int, error) {
switch fid.File() {
default:
return 0, fmt.Errorf("unknown file")
case cons:
return c.consRead(ctx, data)
}
},
Write: func(ctx context.Context, fid *srv9p.Fid, data []byte, offset int64) (int, error) {
switch fid.File() {
default:
return 0, fmt.Errorf("unknown file")
case cons:
return c.consWrite(ctx, data)
case consctl:
return c.consctlWrite(data)
}
},
Clunk: func(fid *srv9p.Fid) {
if fid.File() == consctl {
c.consctlClose()
}
},
}
if Verbose {
srv.Trace = os.Stderr
}
p1, p2, err := os.Pipe()
if err != nil {
log.Fatal(err)
}
go srv.Serve(p1, p1)
// Child process runs with the 9P service on stdin (pipes are bidirectional),
// leaving stdout and stderr directly connected to the parent's stdout/stderr
// for printing any last gasp errors.
// The child mounts the 9P session and then runs a shell or other command.
exe, err := os.Executable()
if err != nil {
log.Fatal(err)
}
cmd := exec.Command("/bin/auth/newns", exe)
cmd.Env = append(os.Environ(), Env+"=1")
cmd.Stdin = p2
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.SysProcAttr = &syscall.SysProcAttr{Rfork: syscall.RFNOTEG | syscall.RFNAMEG}
err = cmd.Start()
p2.Close()
if err != nil {
log.Fatal(err)
}
cmd.Wait()
}
func runChild() {
// Note: locked on main thread, so RFNOTEG and RFNAMEG will not migrate elsewhere.
syscall.RawSyscall(syscall.SYS_RFORK, syscall.RFNOTEG|syscall.RFNAMEG, 0, 0)
// Mount console device from parent process onto /dev and open.
if err := syscall.Mount(0, -1, "/dev", syscall.MBEFORE, ""); err != nil {
log.Fatalf("mount /dev: %v", err)
}
cons, err := syscall.Open("/dev/cons", syscall.O_RDWR)
if err != nil {
log.Fatal(err)
}
// Tell parent to open our note group file for sending interrupts.
consctl, err := syscall.Open("/dev/consctl", syscall.O_WRONLY)
if err == nil {
syscall.Write(consctl, []byte(fmt.Sprintf("notepg %d", os.Getpid())))
syscall.Close(consctl)
} else if err != nil {
log.Print(err)
}
// Put /dev/cons on stdin, stdout, stderr and exec command.
syscall.Dup(cons, 0)
syscall.Dup(cons, 1)
syscall.Dup(cons, 2)
if cons > 2 {
syscall.Close(cons)
}
args := flag.Args()
if len(args) == 0 {
args = []string{"/bin/rc", "-l"}
}
err = syscall.Exec(args[0], args, append(os.Environ(), "service=netshell"))
log.Fatal(err)
}
// A rendez is a simple sleep/wakeup primitive (like a condition variable)
// based on a channel. Using a channel lets us sleep on the rendez until
// either it becomes ready or a context is canceled.
type rendez chan bool
func newRendez() rendez {
return make(rendez, 1)
}
// Sleep sleeps until either something calls r.Wakeup or the context is canceled.
func (r rendez) Sleep(ctx context.Context) {
select {
case <-ctx.Done():
case <-r:
}
}
// Wakeup wakes up one call to r.Sleep or returns immediately if
// there are no calls sleeping.
func (r rendez) Wakeup() {
select {
default:
case r <- true:
}
}
const (
maxLine = 4096 // max line buffer
maxBuf = 8192 // max read/write buffer
)
// A console implements a simple terminal-like device reading from
// r and writing to w.
type console struct {
r io.Reader // reader connected to network
w io.Writer // writer connected to network
mu sync.Mutex
notefd int
raw bool
line []byte // line buffer
read []byte // from network
readErr error
readEmpty rendez
readFull rendez
write []byte // to network
writeErr error
writeEmpty rendez
writeFull rendez
}
// newConsole creates a new console reading from r and writing to w.
func newConsole(r io.Reader, w io.Writer) *console {
c := &console{
r: r,
w: w,
notefd: -1,
readEmpty: newRendez(),
readFull: newRendez(),
writeEmpty: newRendez(),
writeFull: newRendez(),
}
ctx, cancel := context.WithCancel(context.Background())
go c.readNet(ctx)
go c.writeNet(ctx)
_ = cancel
return c
}
// consctlClose handles a close of /dev/consctl; it turns raw mode off.
func (c *console) consctlClose() {
c.mu.Lock()
defer c.mu.Unlock()
c.raw = false
}
// consctlWrite handles writes to /dev/consctl.
func (c *console) consctlWrite(data []byte) (int, error) {
c.mu.Lock()
defer c.mu.Unlock()
s := strings.TrimSpace(string(data))
switch s {
case "rawon": // turn raw mode on
c.raw = true
c.read = append(c.read, c.line...)
c.line = nil
return len(data), nil
case "rawoff": // turn raw mode off
c.raw = false
return len(data), nil
}
if s, ok := strings.CutPrefix(s, "notepg"); ok { // notepg n means send interrupt notes to /proc/n/notepg
if _, err := strconv.ParseUint(s, 10, 64); err != nil {
return 0, fmt.Errorf("bad notepg")
}
fd, err := syscall.Open("/proc/"+s+"/notepg", syscall.O_WRONLY)
if err != nil {
return 0, err
}
c.notefd = fd
return len(data), nil
}
return 0, fmt.Errorf("unknown control message")
}
// readNet reads bytes from the network connection
// and adds them to the read buffer for use by /dev/cons.
func (c *console) readNet(ctx context.Context) {
buf := make([]byte, 4096)
for context.Cause(ctx) == nil {
n, err := c.r.Read(buf)
if n > 0 {
c.consType(ctx, buf[:n])
}
if err != nil {
return
}
}
}
const (
Backspace = 'H' - '@'
Delete = 0x7F
CtrlC = 'C' - '@'
CtrlD = 'D' - '@'
CtrlU = 'U' - '@'
CtrlW = 'W' - '@'
)
// consType processes typed characters, adding them to the console.
func (c *console) consType(ctx context.Context, data []byte) {
c.mu.Lock()
defer c.mu.Unlock()
if c.raw {
c.addRead(ctx, data)
return
}
for _, ch := range data {
if len(c.line) >= maxLine { // too much, just send it
c.addRead(ctx, c.line)
c.line = c.line[:0]
}
switch ch {
default:
c.consWriteLocked(ctx, []byte{ch})
c.line = append(c.line, ch)
case '\r', '\n':
ch = '\n'
c.consWriteLocked(ctx, []byte{ch})
c.line = append(c.line, ch)
c.addRead(ctx, c.line)
c.line = c.line[:0]
case CtrlC:
if c.notefd >= 0 {
syscall.Write(c.notefd, []byte("interrupt"))
}
c.consWriteLocked(ctx, []byte(fmt.Sprintf("^C")))
case CtrlD:
c.consWriteLocked(ctx, []byte("^D"))
c.line = append(c.line, CtrlD)
c.addRead(ctx, c.line)
c.line = c.line[:0]
case Backspace, Delete:
if len(c.line) > 0 {
_, size := utf8.DecodeLastRune(c.line)
c.line = c.line[:len(c.line)-size]
c.consWriteLocked(ctx, []byte{ch})
}
case CtrlW:
deleted := false
for len(c.line) > 0 {
r, size := utf8.DecodeLastRune(c.line)
alnum := unicode.IsLetter(r) || unicode.IsDigit(r)
if alnum {
deleted = true
} else if deleted {
break
}
c.line = c.line[:len(c.line)-size]
c.consWriteLocked(ctx, []byte{Backspace})
}
case CtrlU:
if len(c.line) > 0 {
c.consWriteLocked(ctx, []byte("^U\n"))
c.line = c.line[:0]
}
}
}
}
// addRead adds data to the read buffer.
func (c *console) addRead(ctx context.Context, data []byte) (int, error) {
b := data
for len(b) > 0 {
if err := context.Cause(ctx); err != nil {
return len(data) - len(b), err
}
n := min(maxBuf-len(c.read), len(b))
if n <= 0 {
c.mu.Unlock()
c.readFull.Sleep(ctx)
c.mu.Lock()
continue
}
c.read = append(c.read, b[:n]...)
b = b[n:]
c.readEmpty.Wakeup()
}
return len(data), nil
}
// consRead uses the read buffer to satisfy a 9P read of /dev/cons.
func (c *console) consRead(ctx context.Context, data []byte) (int, error) {
c.mu.Lock()
defer c.mu.Unlock()
for {
if err := context.Cause(ctx); err != nil {
return 0, err
}
if len(c.read) == 0 {
c.mu.Unlock()
c.readEmpty.Sleep(ctx)
c.mu.Lock()
continue
}
if c.raw {
n := copy(data, c.read)
c.read = c.read[:copy(c.read, c.read[n:])]
c.readFull.Wakeup()
return n, nil
}
// Identify next line.
n := min(len(data), len(c.read))
if i := bytes.IndexByte(c.read[:n], '\n'); i >= 0 {
n = i + 1
}
if i := bytes.IndexByte(c.read[:n], CtrlD); i >= 0 {
n = i + 1
}
copy(data, c.read[:n])
c.read = c.read[:copy(c.read, c.read[n:])]
c.readFull.Wakeup()
if n > 0 && data[n-1] == CtrlD {
n--
}
return n, nil
}
}
// consWrite handles a write to /dev/cons by adding data to the write buffer.
func (c *console) consWrite(ctx context.Context, data []byte) (int, error) {
c.mu.Lock()
defer c.mu.Unlock()
return c.consWriteLocked(ctx, data)
}
func (c *console) consWriteLocked(ctx context.Context, data []byte) (int, error) {
b := data
for len(b) > 0 {
if err := context.Cause(ctx); err != nil {
return len(data) - len(b), err
}
n := min(maxBuf-len(c.write), len(b))
if n <= 0 {
c.mu.Unlock()
c.writeFull.Sleep(ctx)
c.mu.Lock()
continue
}
c.write = append(c.write, b[:n]...)
b = b[n:]
c.writeEmpty.Wakeup()
}
return len(data), nil
}
// writeNet writes bytes from the write buffer to the network connection.
func (c *console) writeNet(ctx context.Context) {
c.mu.Lock()
defer c.mu.Unlock()
var withCR []byte
for context.Cause(ctx) == nil {
if len(c.write) == 0 {
c.mu.Unlock()
c.writeEmpty.Sleep(ctx)
c.mu.Lock()
continue
}
b := c.write
c.mu.Unlock()
withCR = withCR[:0]
for _, b := range b {
if b == '\n' {
withCR = append(withCR, '\r', '\n')
} else {
withCR = append(withCR, b)
}
}
_, err := c.w.Write(withCR)
c.mu.Lock()
if err != nil {
c.writeErr = err
return
}
c.write = c.write[:copy(c.write, c.write[len(b):])]
c.writeFull.Wakeup()
}
}