109 lines
3.0 KiB
Go
109 lines
3.0 KiB
Go
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package main
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import (
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"github.com/BRNSystems/go-telnet"
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"github.com/reiver/go-oi"
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"strings"
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)
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type InternalTerminalHandler struct {
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ShellCharacter string
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WelcomeMessage string
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CommandRegistry *CommandRegistry
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}
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func NewInternalTerminalHandler(shellCharacter, welcomeMessage string, commandRegistry *CommandRegistry) *InternalTerminalHandler {
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return &InternalTerminalHandler{
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ShellCharacter: shellCharacter,
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WelcomeMessage: welcomeMessage,
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CommandRegistry: commandRegistry,
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}
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}
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func (handler *InternalTerminalHandler) ServeTELNET(ctx telnet.Context, w telnet.Writer, r telnet.Reader) {
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clientID := NewClient(ctx, w, r)
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defer RemoveClient(clientID)
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w.RawWrite([]byte{0xff, 0xfb, 0x03}) //send char by char
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w.RawWrite([]byte{0xff, 0xfb, 0x01}) //echo from server
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w.Write([]byte(strings.ReplaceAll(handler.WelcomeMessage, "\n", "\r\n") + "\r\n"))
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//replace every \n with \r\n in WelcomeMessage
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w.Write([]byte(handler.ShellCharacter))
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var lineBuffer []byte
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CSISequence := 0
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for {
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var bt [1]byte
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n, err := r.Read(bt[:])
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if err != nil {
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break
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}
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if n > 0 {
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b := bt[0]
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if b == 0x03 || b == 0x04 {
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return
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} else if b == 0x1B { //escape
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CSISequence = 1
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} else if CSISequence == 1 && b == 0x5B {
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CSISequence = 2
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} else if CSISequence == 2 && b == 'A' {
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if len(lineBuffer) == 0 && len(clients[clientID].History) > 0 {
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if clients[clientID].HistoryIndex < len(clients[clientID].History)-1 {
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clients[clientID].HistoryIndex++
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}
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lineBuffer = []byte(clients[clientID].History[clients[clientID].HistoryIndex])
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w.RawWrite([]byte{0x1B, 0x5B, 0x4B}) //clear line
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w.Write(lineBuffer)
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}
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} else if CSISequence == 2 && b == 'B' {
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if len(lineBuffer) == 0 && len(clients[clientID].History) > 0 {
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if clients[clientID].HistoryIndex > 0 {
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clients[clientID].HistoryIndex--
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}
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lineBuffer = []byte(clients[clientID].History[clients[clientID].HistoryIndex])
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w.RawWrite([]byte{0x1B, 0x5B, 0x4B}) //clear line
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w.Write(lineBuffer)
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}
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} else if b == 0x7F {
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if len(lineBuffer) > 0 {
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w.Write([]byte{0x08, 0x20, 0x08})
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lineBuffer = lineBuffer[:len(lineBuffer)-1]
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}
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} else if b != '\r' && b != '\n' && b != 0 {
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CSISequence = 0
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lineBuffer = append(lineBuffer, b)
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w.RawWrite([]byte{b})
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} else if b == '\r' {
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w.Write([]byte("\r\n"))
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command := string(lineBuffer)
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args := strings.Fields(command)
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var message string
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if len(args) > 0 {
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cmd := args[0]
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if cmd == "exit" {
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return
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}
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handlerFunc, ok, clientID := handler.CommandRegistry.GetCommandHandler(cmd, clientID)
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clients[clientID].HistoryIndex = 0
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if ok {
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message = handlerFunc(args[1:], clientID)
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clients[clientID].History = append(clients[clientID].History, command)
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} else {
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message = "Command not found"
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}
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message += "\n" + handler.ShellCharacter
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} else {
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message = handler.ShellCharacter
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}
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oi.LongWrite(w, []byte(strings.ReplaceAll(message, "\n", "\r\n")))
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lineBuffer = nil
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}
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}
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}
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}
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