1 files changed, 287 insertions, 0 deletions
diff --git a/eows/eows.go b/eows/eows.go
new file mode 100644
index 0000000..9d0b520
--- /dev/null
+++ b/eows/eows.go
@@ -0,0 +1,287 @@
+// Package eows is used to Execute commands Over WebSocket
+package eows
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/googollee/go-socket.io"
+	"github.com/kr/pty"
+)
+
+// OnInputCB is the function callback used to receive data
+type OnInputCB func(e *ExecOverWS, stdin []byte) ([]byte, error)
+
+// EmitOutputCB is the function callback used to emit data
+type EmitOutputCB func(e *ExecOverWS, stdout, stderr []byte)
+
+// EmitExitCB is the function callback used to emit exit proc code
+type EmitExitCB func(e *ExecOverWS, code int, err error)
+
+// SplitType Type of spliting method to tokenize stdout/stderr
+type SplitType uint8
+
+const (
+	// SplitLine Split line by line
+	SplitLine SplitType = iota
+	// SplitChar Split character by character
+	SplitChar
+	// SplitLineTime Split by line or until a timeout has passed
+	SplitLineTime
+	// SplitTime Split until a timeout has passed
+	SplitTime
+)
+
+// Inspired by :
+// https://github.com/gorilla/websocket/blob/master/examples/command/main.go
+
+// ExecOverWS .
+type ExecOverWS struct {
+	Cmd      string           // command name to execute
+	Args     []string         // command arguments
+	SocketIO *socketio.Socket // websocket
+	Sid      string           // websocket ID
+	CmdID    string           // command ID
+
+	// Optional fields
+	Env            []string                // command environment variables
+	CmdExecTimeout int                     // command execution time timeout
+	Log            *logrus.Logger          // logger (nil if disabled)
+	InputEvent     string                  // websocket input event name
+	InputCB        OnInputCB               // stdin callback
+	OutputCB       EmitOutputCB            // stdout/stderr callback
+	ExitCB         EmitExitCB              // exit proc callback
+	UserData       *map[string]interface{} // user data passed to callbacks
+	OutSplit       SplitType               // split method to tokenize stdout/stderr
+	LineTimeSpan   int64                   // time span (only used with SplitTime or SplitLineTime)
+	PtyMode        bool                    // Allocate a pseudo-terminal (allow to execute screen-based program)
+	PtyTermEcho    bool                    // Turn on/off terminal echo
+
+	// Private fields
+
+	proc       *os.Process
+	command    *exec.Cmd
+	ptmx       *os.File
+	procExited bool
+}
+
+var cmdIDMap = make(map[string]*ExecOverWS)
+
+// New creates a new instace of eows
+func New(cmd string, args []string, so *socketio.Socket, soID, cmdID string) *ExecOverWS {
+
+	e := &ExecOverWS{
+		Cmd:            cmd,
+		Args:           args,
+		SocketIO:       so,
+		Sid:            soID,
+		CmdID:          cmdID,
+		CmdExecTimeout: -1,            // default no timeout
+		OutSplit:       SplitLineTime, // default split by line with time
+		LineTimeSpan:   500 * time.Millisecond.Nanoseconds(),
+		PtyMode:        false,
+		PtyTermEcho:    true,
+	}
+
+	cmdIDMap[cmdID] = e
+
+	return e
+}
+
+// GetEows gets ExecOverWS object from command ID
+func GetEows(cmdID string) *ExecOverWS {
+	if _, ok := cmdIDMap[cmdID]; !ok {
+		return nil
+	}
+	return cmdIDMap[cmdID]
+}
+
+// Start executes the command and redirect stdout/stderr into a WebSocket
+func (e *ExecOverWS) Start() error {
+	var err error
+	var outr, outw, errr, errw, inr, inw *os.File
+
+	bashArgs := []string{"/bin/bash", "-c", e.Cmd + " " + strings.Join(e.Args, " ")}
+
+	// no timeout == 1 year
+	if e.CmdExecTimeout == -1 {
+		e.CmdExecTimeout = 365 * 24 * 60 * 60
+	}
+
+	e.procExited = false
+
+	if e.PtyMode {
+
+		e.command = exec.Command(bashArgs[0], bashArgs[1:]...)
+		e.command.Env = append(os.Environ(), e.Env...)
+		e.ptmx, err = pty.Start(e.command)
+		if err != nil {
+			err = fmt.Errorf("Process start error: " + err.Error())
+			goto exitErr
+		}
+		e.proc = e.command.Process
+
+		// Turn off terminal echo
+		if !e.PtyTermEcho {
+			e.terminalEcho(e.ptmx, false)
+		}
+
+	} else {
+
+		// Create pipes
+		outr, outw, err = os.Pipe()
+		if err != nil {
+			err = fmt.Errorf("Pipe stdout error: " + err.Error())
+			goto exitErr
+		}
+
+		errr, errw, err = os.Pipe()
+		if err != nil {
+			err = fmt.Errorf("Pipe stderr error: " + err.Error())
+			goto exitErr
+		}
+
+		inr, inw, err = os.Pipe()
+		if err != nil {
+			err = fmt.Errorf("Pipe stdin error: " + err.Error())
+			goto exitErr
+		}
+
+		e.proc, err = os.StartProcess(bashArgs[0], bashArgs, &os.ProcAttr{
+			Files: []*os.File{inr, outw, errw},
+			Env:   append(os.Environ(), e.Env...),
+		})
+		if err != nil {
+			err = fmt.Errorf("Process start error: " + err.Error())
+			goto exitErr
+		}
+	}
+
+	go func() {
+		stdoutDone := make(chan struct{})
+
+		if e.PtyMode {
+			// Make sure to close the pty at the end.
+			defer e.ptmx.Close()
+
+			// Handle both stdout mixed with stderr
+			go e.ptsPumpStdout(e.ptmx, stdoutDone)
+
+			// Blocking function that poll input or wait for end of process
+			e.pumpStdin(e.ptmx)
+
+		} else {
+			// Make sure to close all pipes
+			defer outr.Close()
+			defer outw.Close()
+			defer errr.Close()
+			defer errw.Close()
+			defer inr.Close()
+			defer inw.Close()
+
+			// Handle stdout + stderr
+			go e.pipePumpStdout(outr, stdoutDone)
+			go e.pipePumpStderr(errr)
+
+			// Blocking function that poll input or wait for end of process
+			e.pumpStdin(inw)
+		}
+
+		if status, err := e.proc.Wait(); err == nil {
+			// Other commands need a bonk on the head.
+			if !status.Exited() {
+				if err := e.proc.Signal(os.Interrupt); err != nil {
+					e.logError("Proc interrupt:", err)
+				}
+
+				select {
+				case <-stdoutDone:
+				case <-time.After(time.Second):
+					// A bigger bonk on the head.
+					if err := e.proc.Signal(os.Kill); err != nil {
+						e.logError("Proc term:", err)
+					}
+					<-stdoutDone
+				}
+			}
+		}
+
+		delete(cmdIDMap, e.CmdID)
+	}()
+
+	return nil
+
+exitErr:
+	for _, pf := range []*os.File{outr, outw, errr, errw, inr, inw} {
+		pf.Close()
+	}
+	return err
+}
+
+// TerminalSetSize Set terminal size
+func (e *ExecOverWS) TerminalSetSize(rows, cols uint16) error {
+	if !e.PtyMode || e.ptmx == nil {
+		return fmt.Errorf("PtyMode not set")
+	}
+	w, err := pty.GetsizeFull(e.ptmx)
+	if err != nil {
+		return err
+	}
+	return e.TerminalSetSizePos(rows, cols, w.X, w.Y)
+}
+
+// TerminalSetSizePos Set terminal size and position
+func (e *ExecOverWS) TerminalSetSizePos(rows, cols, x, y uint16) error {
+	if !e.PtyMode || e.ptmx == nil {
+		return fmt.Errorf("PtyMode not set")
+	}
+	winSz := pty.Winsize{Rows: rows, Cols: cols, X: x, Y: y}
+	return pty.Setsize(e.ptmx, &winSz)
+}
+
+/**
+ * Private functions
+ **/
+
+// terminalEcho Enable or disable echoing terminal input.
+// This is useful specifically for when users enter passwords.
+func (e *ExecOverWS) terminalEcho(ff *os.File, show bool) {
+	var termios = &syscall.Termios{}
+
+	fd := ff.Fd()
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd,
+		syscall.TCGETS, uintptr(unsafe.Pointer(termios))); err != 0 {
+		return
+	}
+
+	if show {
+		termios.Lflag |= syscall.ECHO
+	} else {
+		termios.Lflag &^= syscall.ECHO
+	}
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd,
+		uintptr(syscall.TCSETS),
+		uintptr(unsafe.Pointer(termios))); err != 0 {
+		return
+	}
+}
+
+func (e *ExecOverWS) logDebug(format string, a ...interface{}) {
+	if e.Log != nil {
+		e.Log.Debugf(format, a...)
+	}
+}
+
+func (e *ExecOverWS) logError(format string, a ...interface{}) {
+	if e.Log != nil {
+		e.Log.Errorf(format, a...)
+	}
+}