mirror of
https://gogs.blitter.com/RLabs/xs
synced 2024-08-14 10:26:42 +00:00
Some cleanup in prep for possible io.ReadFull() fixed-block session-cmd header to resolve the eaten-byte issue handing Accept off to cmdRunner
This commit is contained in:
Russ Magee
parent
49c589ee8d
commit
732005d9bf
2 changed files with 53 additions and 110 deletions
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@ -10,6 +10,7 @@ import (
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"sync"
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hkex "blitter.com/herradurakex"
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isatty "github.com/mattn/go-isatty"
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"golang.org/x/sys/unix"
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)
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@ -31,6 +32,7 @@ func main() {
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var cAlg string
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var hAlg string
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var server string
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isInteractive := false
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flag.StringVar(&cAlg, "c", "C_AES_256", "cipher [\"C_AES_256\" | \"C_TWOFISH_128\" | \"C_BLOWFISH_64\"]")
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flag.StringVar(&hAlg, "h", "H_SHA256", "hmac [\"H_SHA256\"]")
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@ -46,20 +48,27 @@ func main() {
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}
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defer conn.Close()
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// Set stdin in raw mode.
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oldState, err := MakeRaw(int(os.Stdin.Fd()))
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if err != nil {
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panic(err)
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// Set stdin in raw mode if it's an interactive session
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if isatty.IsTerminal(os.Stdin.Fd()) {
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isInteractive = true
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oldState, err := MakeRaw(int(os.Stdin.Fd()))
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if err != nil {
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panic(err)
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}
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defer func() { _ = Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
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} else {
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fmt.Println("NOT A TTY")
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}
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defer func() { _ = Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
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wg.Add(1)
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go func() {
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// This will guarantee the side that closes first
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// marks its direction's goroutine as finished.
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// By deferring a call to wg.Done(),
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// each goroutine guarantees that it marks
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// its direction's stream as finished.
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//
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// Whichever direction's goroutine finishes first
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// will call wg.Done() once more explicitly to
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// hang up on the other side so the client
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// will call wg.Done() once more, explicitly, to
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// hang up on the other side, so that this client
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// exits immediately on an EOF from either side.
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defer wg.Done()
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@ -72,8 +81,10 @@ func main() {
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os.Exit(1)
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}
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}
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log.Println("[Got Write EOF]")
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wg.Done() // client hanging up, close server read goroutine
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if isInteractive {
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log.Println("[Got Write EOF]")
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wg.Done() // client hanging up, close WaitGroup to exit client
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}
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}()
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wg.Add(1)
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@ -90,7 +101,7 @@ func main() {
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}
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}
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log.Println("[Got Read EOF]")
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wg.Done() // server hung up, close client write goroutine
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wg.Done() // server hung up, close WaitGroup to exit client
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}()
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// Wait until both stdin and stdout goroutines finish
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@ -99,13 +110,16 @@ func main() {
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/* ------------- minimal terminal APIs brought in from ssh/terminal
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* (they have no real business being there as they aren't specific to
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* ssh.)
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* ssh, but as of v1.10, early 2018, core go stdlib hasn't yet done
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* the planned terminal lib reorgs.)
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* -------------
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*/
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// From github.com/golang/crypto/blob/master/ssh/terminal/util_linux.go
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const ioctlReadTermios = unix.TCGETS
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const ioctlWriteTermios = unix.TCSETS
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// From github.com/golang/crypto/blob/master/ssh/terminal/util.go
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// State contains the state of a terminal.
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type State struct {
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termios unix.Termios
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@ -16,6 +16,9 @@ import (
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"github.com/kr/pty"
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)
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// Unused, probably obsolete. Once interactive session
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// and piped I/O one-shot commands are working reconsider
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// how Op might be used
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const (
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OpR = 'r' // read(file) (binary mode)
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OpW = 'w' // (over)write
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@ -39,78 +42,11 @@ type cmdRunner struct {
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status int
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}
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/* ------------- minimal terminal APIs brought in from ssh/terminal
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* (they have no real business being there as they aren't specific to
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* ssh.)
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* -------------
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*/
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/*
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// MakeRaw put the terminal connected to the given file descriptor into raw
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// mode and returns the previous state of the terminal so that it can be
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// restored.
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func MakeRaw(fd int) (*State, error) {
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termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
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if err != nil {
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return nil, err
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}
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oldState := State{termios: *termios}
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// This attempts to replicate the behaviour documented for cfmakeraw in
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// the termios(3) manpage.
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termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
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termios.Oflag &^= unix.OPOST
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termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN
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termios.Cflag &^= unix.CSIZE | unix.PARENB
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termios.Cflag |= unix.CS8
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termios.Cc[unix.VMIN] = 1
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termios.Cc[unix.VTIME] = 0
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if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, termios); err != nil {
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return nil, err
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}
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return &oldState, nil
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}
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// GetState returns the current state of a terminal which may be useful to
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// restore the terminal after a signal.
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func GetState(fd int) (*State, error) {
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termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
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if err != nil {
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return nil, err
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}
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return &State{termios: *termios}, nil
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}
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// Restore restores the terminal connected to the given file descriptor to a
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// previous state.
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func Restore(fd int, state *State) error {
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return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
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}
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*/
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/* -------------------------------------------------------------- */
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/*
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func cmd(r *cmdRunner) {
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switch r.op {
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case OpR:
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//Clean up r.cmd beforehand
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r.arg = strings.TrimSpace(r.arg)
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fmt.Printf("[cmd was:'%s']\n", r.arg)
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runCmdAs(r.who, r.arg, nil)
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fmt.Println(r.arg)
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break
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default:
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fmt.Printf("[cmd %d ignored:%d]\n", int(r.op))
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break
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}
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}
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*/
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// Run a command (via os.exec) as a specific user
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//
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// Uses ptys to support commands which expect a terminal.
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func runCmdAs(who string, cmd string, conn hkex.Conn) (err error) {
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u, _ := user.Lookup(who)
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var uid, gid uint32
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@ -183,6 +119,7 @@ func main() {
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// multiple connections may be served concurrently.
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go func(c hkex.Conn) (e error) {
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defer c.Close()
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var connOp *byte = nil
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ch := make(chan []byte)
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chN := 0
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eCh := make(chan error)
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@ -204,8 +141,6 @@ func main() {
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}(ch, eCh)
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ticker := time.Tick(time.Second / 100)
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//var r cmdRunner
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var connOp *byte = nil
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Term:
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// continuously read from the connection
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for {
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@ -216,39 +151,33 @@ func main() {
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fmt.Printf("Client sent %+v\n", data[0:chN])
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if connOp == nil {
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// Initial xmit - get op byte
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// (TODO: determine valid ops
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// for now 'e' (echo), 'i' (interactive), 'x' (exec), ... ?)
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// Have op here and first block of data[]
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connOp = new(byte)
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*connOp = data[0]
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fmt.Printf("[* connOp '%c']\n", *connOp)
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}
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if len(data) > 1 {
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data = data[1:chN]
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chN -= 1
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// Have op here and first block of data[]
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fmt.Printf("[* connOp '%c']\n", *connOp)
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// The CloseHandler typically handles the
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// accumulated command data
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//r = cmdRunner{op: Op(*connOp),
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// who: "larissa", arg: string(data),
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// authCookie: "c00ki3",
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// status: 0}
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}
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// From here, one could pass all subsequent data
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// between client/server attached to an exec.Cmd,
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// as data to/from a file, etc.
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if *connOp == 's' {
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fmt.Println("[Running shell]")
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runCmdAs("larissa", "bash -l -i", conn)
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// Returned hopefully via an EOF or exit/logout;
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// Clear current op so user can enter next, or EOF
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connOp = nil
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fmt.Println("[Exiting shell]")
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conn.Close()
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if len(data) > 0 {
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// From here, one could pass all subsequent data
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// between client/server attached to an exec.Cmd,
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// as data to/from a file, etc.
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if connOp != nil && *connOp == 's' {
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fmt.Println("[Running shell]")
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runCmdAs("larissa", "bash -l -i", conn)
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// Returned hopefully via an EOF or exit/logout;
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// Clear current op so user can enter next, or EOF
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connOp = nil
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fmt.Println("[Exiting shell]")
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conn.Close()
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}
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if strings.Trim(string(data), "\r\n") == "exit" {
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conn.Close()
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}
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}
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if strings.Trim(string(data), "\r\n") == "exit" {
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conn.Close()
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}
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//fmt.Printf("Client sent %s\n", string(data))
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// This case means we got an error and the goroutine has finished
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case err := <-eCh:
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