mirror of
https://github.com/syssecfsu/witty.git
synced 2024-12-25 04:02:36 +01:00
435 lines
10 KiB
Go
435 lines
10 KiB
Go
//This file contains code to relay traffic between websocket and pty
|
|
package term_conn
|
|
|
|
import (
|
|
"encoding/json"
|
|
"log"
|
|
"net/http"
|
|
"os"
|
|
"os/exec"
|
|
"strconv"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/creack/pty"
|
|
"github.com/gorilla/websocket"
|
|
)
|
|
|
|
const (
|
|
// Time allowed to write a message to the peer.
|
|
readWait = 10 * time.Second
|
|
writeWait = 10 * time.Second
|
|
viewWait = 3 * time.Second
|
|
|
|
// Time allowed to read the next pong message from the peer.
|
|
pongWait = 10 * time.Second
|
|
|
|
// Maximum message size allowed from peer.
|
|
maxMessageSize = 4096
|
|
readBufferSize = 1024
|
|
WriteBufferSize = 1024
|
|
|
|
// Send pings to peer with this period. Must be less than pongWait.
|
|
pingPeriod = (pongWait * 9) / 10
|
|
|
|
recordCmd = 1
|
|
stopCmd = 0
|
|
)
|
|
|
|
var upgrader = websocket.Upgrader{
|
|
ReadBufferSize: readBufferSize,
|
|
WriteBufferSize: WriteBufferSize,
|
|
CheckOrigin: func(r *http.Request) bool {
|
|
return true
|
|
},
|
|
}
|
|
|
|
// TermConn represents the connected websocket and pty.
|
|
// if isViewer is true
|
|
type TermConn struct {
|
|
Name string
|
|
Ip string
|
|
|
|
ws *websocket.Conn
|
|
ptmx *os.File // the pty that runs the command
|
|
record *os.File // record session
|
|
lastRecTime time.Time // last time a record is written
|
|
cmd *exec.Cmd // represents the process, we need it to terminate the process
|
|
viewChan chan *websocket.Conn // channel to receive viewers
|
|
recordChan chan int // channel to start/stop recording
|
|
ws_done chan struct{} // ws is closed, only close this chan in ws reader
|
|
pty_done chan struct{} // pty is closed, close this chan in pty reader
|
|
}
|
|
|
|
type WriteRecord struct {
|
|
Dur time.Duration `json:"Duration"`
|
|
Data []byte `json:"Data"`
|
|
}
|
|
|
|
func (tc *TermConn) createPty(cmdline []string) error {
|
|
// Create a shell command.
|
|
cmd := exec.Command(cmdline[0], cmdline[1:]...)
|
|
|
|
// Start the command with a pty.
|
|
ptmx, err := pty.Start(cmd)
|
|
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Use fixed size, the xterm is initalized as 122x37,
|
|
// But we set pty to 120x36. Using fullsize will lead
|
|
// some program to misbehave.
|
|
pty.Setsize(ptmx, &pty.Winsize{
|
|
Cols: 120,
|
|
Rows: 36,
|
|
})
|
|
|
|
tc.ptmx = ptmx
|
|
tc.cmd = cmd
|
|
|
|
log.Printf("Create shell process %v (%v)", cmdline, cmd.Process.Pid)
|
|
return nil
|
|
}
|
|
|
|
// Periodically send ping message to detect the status of the ws
|
|
func (tc *TermConn) ping(wg *sync.WaitGroup) {
|
|
defer wg.Done()
|
|
|
|
ticker := time.NewTicker(pingPeriod)
|
|
defer ticker.Stop()
|
|
|
|
out:
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
err := tc.ws.WriteControl(websocket.PingMessage,
|
|
[]byte{}, time.Now().Add(writeWait))
|
|
|
|
if err != nil {
|
|
log.Println("Failed to write ping message:", err)
|
|
break out
|
|
}
|
|
case <-tc.pty_done:
|
|
log.Println("Exit ping routine as pty is going away")
|
|
break out
|
|
|
|
case <-tc.ws_done:
|
|
log.Println("Exit ping routine as ws is going away")
|
|
break out
|
|
}
|
|
}
|
|
|
|
log.Println("Ping routine exited")
|
|
}
|
|
|
|
// shovel data from websocket to pty stdin
|
|
func (tc *TermConn) wsToPtyStdin(wg *sync.WaitGroup) {
|
|
defer wg.Done()
|
|
|
|
tc.ws.SetReadLimit(maxMessageSize)
|
|
|
|
// set the readdeadline. The idea here is simple,
|
|
// as long as we keep receiving pong message,
|
|
// the readdeadline will keep updating. Otherwise
|
|
// read will timeout.
|
|
tc.ws.SetReadDeadline(time.Now().Add(pongWait))
|
|
tc.ws.SetPongHandler(func(string) error {
|
|
tc.ws.SetReadDeadline(time.Now().Add(pongWait))
|
|
return nil
|
|
})
|
|
|
|
bufChan := make(chan []byte)
|
|
|
|
go func() { //create a goroutine to read from ws
|
|
for {
|
|
_, buf, err := tc.ws.ReadMessage()
|
|
|
|
if err != nil {
|
|
log.Println("Failed to receive data from ws:", err)
|
|
close(bufChan) // close chan by producer
|
|
close(tc.ws_done)
|
|
break
|
|
}
|
|
|
|
bufChan <- buf
|
|
}
|
|
}()
|
|
// we do not need to forward user input to viewers, only the stdout
|
|
out:
|
|
for {
|
|
select {
|
|
case buf, ok := <-bufChan:
|
|
if !ok {
|
|
log.Println("Exit wsToPtyStdin routine pty stdin error")
|
|
break out
|
|
}
|
|
_, err := tc.ptmx.Write(buf)
|
|
|
|
if err != nil {
|
|
log.Println("Failed to send data to pty stdin: ", err)
|
|
break out
|
|
}
|
|
case <-tc.ws_done:
|
|
log.Println("Exit wsToPtyStdin routine as ws is going away")
|
|
break out
|
|
case <-tc.pty_done:
|
|
log.Println("Exit wsToPtyStdin routine as pty is going away")
|
|
break out
|
|
}
|
|
}
|
|
|
|
log.Println("wsToPtyStdin routine exited")
|
|
}
|
|
|
|
// shovel data from pty Stdout to WS
|
|
func (tc *TermConn) ptyStdoutToWs(wg *sync.WaitGroup) {
|
|
var viewers []*websocket.Conn
|
|
|
|
defer wg.Done()
|
|
bufChan := make(chan []byte)
|
|
|
|
go func() { //create a goroutine to read from pty
|
|
for {
|
|
readBuf := make([]byte, 1024) //pty reads in 1024 blocks
|
|
n, err := tc.ptmx.Read(readBuf)
|
|
|
|
if err != nil {
|
|
log.Println("Failed to read from pty stdout: ", err)
|
|
close(bufChan)
|
|
close(tc.pty_done)
|
|
break
|
|
}
|
|
|
|
readBuf = readBuf[0:n] // slice the buffer so that it is exact the size of data read.
|
|
bufChan <- readBuf
|
|
}
|
|
}()
|
|
|
|
out:
|
|
for {
|
|
// handle viewers, we want to use non-blocking receive
|
|
select {
|
|
case buf, ok := <-bufChan:
|
|
if !ok {
|
|
tc.ws.SetWriteDeadline(time.Now().Add(writeWait))
|
|
tc.ws.WriteMessage(websocket.CloseMessage,
|
|
websocket.FormatCloseMessage(websocket.CloseNormalClosure, "Pty closed"))
|
|
|
|
break out
|
|
}
|
|
// We could add ws to viewers as well (then we can use io.MultiWriter),
|
|
// but we want to handle errors differently
|
|
tc.ws.SetWriteDeadline(time.Now().Add(writeWait))
|
|
if err := tc.ws.WriteMessage(websocket.BinaryMessage, buf); err != nil {
|
|
log.Println("Failed to write message: ", err)
|
|
break out
|
|
}
|
|
|
|
//write to the viewer
|
|
for i, w := range viewers {
|
|
if w == nil {
|
|
continue
|
|
}
|
|
|
|
// if the viewer exits, we will just ignore the error
|
|
w.SetWriteDeadline(time.Now().Add(viewWait))
|
|
if err := w.WriteMessage(websocket.BinaryMessage, buf); err != nil {
|
|
log.Println("Failed to write message to viewer: ", err)
|
|
|
|
viewers[i] = nil
|
|
w.Close() // we own the socket and need to close it
|
|
}
|
|
}
|
|
|
|
// Do we need to record the session?
|
|
if tc.record != nil {
|
|
jbuf, err := json.Marshal(WriteRecord{Dur: time.Since(tc.lastRecTime), Data: buf})
|
|
if err != nil {
|
|
log.Println("Failed to marshal record", err)
|
|
} else {
|
|
tc.record.Write([]byte(",")) // write a deliminator
|
|
tc.record.Write(jbuf)
|
|
}
|
|
|
|
tc.lastRecTime = time.Now()
|
|
}
|
|
|
|
case cmd := <-tc.recordChan:
|
|
var err error
|
|
if cmd == recordCmd {
|
|
// use the session ID and current as file name
|
|
fname := "./records/" + tc.Name + "_" + strconv.FormatInt(time.Now().Unix(), 16) + ".scr"
|
|
|
|
tc.record, err = os.OpenFile(fname, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
|
|
if err != nil {
|
|
log.Println("Failed to create record file", fname, err)
|
|
tc.record = nil
|
|
}
|
|
|
|
tc.record.Write([]byte("[")) // write a [ for an array of json objs
|
|
|
|
// write a dummy record to clear the screen.
|
|
tc.lastRecTime = time.Now()
|
|
jbuf, _ := json.Marshal(WriteRecord{Dur: time.Since(tc.lastRecTime), Data: []byte("\033[2J\033[H")})
|
|
tc.record.Write(jbuf)
|
|
|
|
} else {
|
|
tc.record.Write([]byte("]"))
|
|
tc.record.Close()
|
|
tc.record = nil
|
|
}
|
|
|
|
case viewer := <-tc.viewChan:
|
|
log.Println("Received viewer", viewer.RemoteAddr().String())
|
|
viewers = append(viewers, viewer)
|
|
|
|
case <-tc.ws_done:
|
|
log.Println("Exit ptyStdoutToWs routine as ws is going away")
|
|
break out
|
|
|
|
case <-tc.pty_done:
|
|
log.Println("Exit ptyStdoutToWs routine as pty is going away")
|
|
break out // do not block on these two channels
|
|
}
|
|
|
|
}
|
|
|
|
// close the watcher
|
|
for _, w := range viewers {
|
|
if w != nil {
|
|
w.Close()
|
|
}
|
|
}
|
|
|
|
log.Println("ptyStdoutToWs routine exited")
|
|
}
|
|
|
|
// this function should be executed by the main goroutine for the connection
|
|
func (tc *TermConn) release() {
|
|
log.Println("Releasing terminal connection", tc.Name)
|
|
|
|
registry.removePlayer(tc.Name)
|
|
|
|
if tc.ptmx != nil {
|
|
// cleanup the pty and its related process
|
|
tc.ptmx.Close()
|
|
|
|
// terminate the command line process
|
|
proc := tc.cmd.Process
|
|
|
|
// send an interrupt, this will cause the shell process to
|
|
// return from syscalls if any is pending
|
|
if err := proc.Signal(os.Interrupt); err != nil {
|
|
log.Printf("Failed to send Interrupt to shell process(%v): %v ", proc.Pid, err)
|
|
}
|
|
|
|
// Wait for a second for shell process to interrupt before kill it
|
|
time.Sleep(time.Second)
|
|
|
|
log.Printf("Try to kill the shell process(%v)", proc.Pid)
|
|
|
|
if err := proc.Signal(os.Kill); err != nil {
|
|
log.Printf("Failed to send KILL to shell process(%v): %v", proc.Pid, err)
|
|
}
|
|
|
|
if _, err := proc.Wait(); err != nil {
|
|
log.Printf("Failed to wait for shell process(%v): %v", proc.Pid, err)
|
|
}
|
|
|
|
close(tc.viewChan)
|
|
close(tc.recordChan)
|
|
|
|
if tc.record != nil {
|
|
// write a ] and close the file
|
|
tc.record.Write([]byte("]"))
|
|
tc.record.Close()
|
|
tc.record = nil
|
|
}
|
|
}
|
|
|
|
tc.ws.Close()
|
|
}
|
|
|
|
// handle websockets
|
|
func handlePlayer(w http.ResponseWriter, r *http.Request, name string, cmdline []string) {
|
|
ws, err := upgrader.Upgrade(w, r, nil)
|
|
|
|
if err != nil {
|
|
log.Println("Failed to create websocket: ", err)
|
|
return
|
|
}
|
|
|
|
tc := TermConn{
|
|
ws: ws,
|
|
Name: name,
|
|
Ip: ws.RemoteAddr().String(),
|
|
}
|
|
|
|
defer tc.release()
|
|
log.Println("Created the websocket to", ws.RemoteAddr().String())
|
|
|
|
tc.ws_done = make(chan struct{})
|
|
tc.pty_done = make(chan struct{})
|
|
tc.viewChan = make(chan *websocket.Conn)
|
|
tc.recordChan = make(chan int)
|
|
|
|
if err := tc.createPty(cmdline); err != nil {
|
|
log.Println("Failed to create PTY: ", err)
|
|
return
|
|
}
|
|
|
|
registry.addPlayer(&tc)
|
|
|
|
// main event loop to shovel data between ws and pty
|
|
// do not call ptyStdoutToWs in this goroutine, otherwise
|
|
// the websocket will not close. This is because ptyStdoutToWs
|
|
// is usually blocked in the pty.Read
|
|
var wg sync.WaitGroup
|
|
wg.Add(3)
|
|
|
|
go tc.ping(&wg)
|
|
go tc.ptyStdoutToWs(&wg)
|
|
go tc.wsToPtyStdin(&wg)
|
|
|
|
wg.Wait()
|
|
log.Println("Wait returned")
|
|
}
|
|
|
|
// handle websockets
|
|
func handleViewer(w http.ResponseWriter, r *http.Request, path string) {
|
|
ws, err := upgrader.Upgrade(w, r, nil)
|
|
|
|
if err != nil {
|
|
log.Println("Failed to create websocket: ", err)
|
|
return
|
|
}
|
|
|
|
log.Println("Created the websocket to", ws.RemoteAddr().String())
|
|
if !registry.sendToPlayer(path, ws) {
|
|
log.Println("Failed to send websocket to player, close it")
|
|
ws.Close()
|
|
}
|
|
}
|
|
|
|
func ConnectTerm(w http.ResponseWriter, r *http.Request, isViewer bool, name string, cmdline []string) {
|
|
if !isViewer {
|
|
handlePlayer(w, r, name, cmdline)
|
|
} else {
|
|
handleViewer(w, r, name)
|
|
}
|
|
}
|
|
|
|
func Init(checkOrigin func(r *http.Request) bool) {
|
|
upgrader.CheckOrigin = checkOrigin
|
|
registry.init()
|
|
}
|
|
|
|
func StartRecord(id string) {
|
|
registry.recordSession(id, recordCmd)
|
|
}
|
|
|
|
func StopRecord(id string) {
|
|
registry.recordSession(id, stopCmd)
|
|
}
|