the telnet interface now handles IAC aka telnet commands

1 files changed, 129 insertions, 21 deletions

diff --git a/src/helsinki.at/rhimportd/ctrlTelnet.go b/src/helsinki.at/rhimportd/ctrlTelnet.go
index 04d90da..4cbeb56 100644
--- a/src/helsinki.at/rhimportd/ctrlTelnet.go
+++ b/src/helsinki.at/rhimportd/ctrlTelnet.go
@@ -26,6 +26,7 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"helsinki.at/rhimport"
 	"net"
@@ -36,6 +37,13 @@ import (
 
 const (
 	prompt = "> "
+	EOT    = byte(4)
+	IP     = byte(244)
+	WILL   = byte(251)
+	WONT   = byte(252)
+	DO     = byte(253)
+	DONT   = byte(254)
+	IAC    = byte(255)
 )
 
 type TelnetClient struct {
@@ -47,15 +55,25 @@ type TelnetClient struct {
 	ctx     *rhimport.ImportContext
 }
 
-func (c *TelnetClient) write_string(text string) (err error) {
-	if _, err = c.writer.WriteString(text); err != nil {
-		return
+func (c *TelnetClient) write_string(text string) {
+	defer c.writer.Flush()
+
+	data := []byte(text)
+	for {
+		idx := bytes.IndexByte(data, IAC)
+		if idx >= 0 {
+			c.writer.Write(data[:idx+1])
+			c.writer.WriteByte(IAC)
+			data = data[idx+1:]
+		} else {
+			c.writer.Write(data)
+			return
+		}
 	}
-	return c.writer.Flush()
 }
 
-func (c *TelnetClient) say(format string, a ...interface{}) (err error) {
-	return c.write_string(fmt.Sprintf(format, a...) + "\n")
+func (c *TelnetClient) say(format string, a ...interface{}) {
+	c.write_string(fmt.Sprintf(format, a...) + "\n")
 }
 
 func (c *TelnetClient) handle_cmd_help(args []string) {
@@ -272,6 +290,8 @@ func telnet_progress_callback(step int, step_name string, progress float64, user
 }
 
 func telnet_cmd_run(ctx rhimport.ImportContext, out chan<- string) {
+	defer close(out)
+
 	out <- fmt.Sprintf("fetching file from '%s'\n", ctx.SourceUri)
 	if res, err := rhimport.FetchFile(&ctx); err != nil {
 		out <- fmt.Sprintf("fetch file error: %s\n", err)
@@ -294,7 +314,6 @@ func telnet_cmd_run(ctx rhimport.ImportContext, out chan<- string) {
 			rhl.Printf("Fileimport has failed (Cart/Cut %d/%d): %s", res.Cart, res.Cut, res.ErrorString)
 		}
 	}
-	close(out)
 }
 
 func (c *TelnetClient) handle_cmd_run(args []string) {
@@ -343,25 +362,113 @@ func (c *TelnetClient) handle_cmd(cmdstr string) bool {
 	return false
 }
 
-func (c *TelnetClient) handle() {
-	defer c.conn.Close()
+func (c *TelnetClient) handle_iac(iac []byte) bool {
+	if len(iac) < 2 {
+		return false // this shouldn't happen
+	}
 
-	if err := c.write_string(prompt); err != nil {
-		return
+	switch iac[1] {
+	case WILL, WONT: // Don't accept any proposed options
+		iac[1] = DONT
+	case DO, DONT:
+		iac[1] = WONT
+	case IP:
+		// TODO: cancel running command (if any)
+		rhdl.Printf("canceling running process - is not yet implemented!")
+		return false
+	default:
+		rhdl.Printf("ignoring unimplemented telnet command: %X", iac[1])
+		return false
 	}
-	for c.scanner.Scan() {
-		if exit := c.handle_cmd(c.scanner.Text()); exit {
-			return
-		}
+	c.writer.Write(iac)
+	c.writer.Flush()
 
-		if err := c.write_string(prompt); err != nil {
-			return
+	return false
+}
+
+func dropCR(data []byte) []byte {
+	if len(data) > 0 && data[len(data)-1] == '\r' {
+		return data[0 : len(data)-1]
+	}
+	return data
+}
+
+func compare_idx(a, b int) int {
+	if a < 0 {
+		a = int(^uint(0) >> 1)
+	}
+	if b < 0 {
+		b = int(^uint(0) >> 1)
+	}
+	return a - b
+}
+
+func ScanLinesTelnet(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
+
+	inl := bytes.IndexByte(data, '\n') // index of first newline character
+	ieot := bytes.IndexByte(data, EOT) // index of first End of Transmission
+	iiac := bytes.IndexByte(data, IAC) // index of first telnet IAC
+
+	if inl >= 0 && compare_idx(inl, ieot) < 0 && compare_idx(inl, iiac) < 0 {
+		return inl + 1, dropCR(data[0:inl]), nil // found a complete line
+	}
+	if ieot >= 0 && compare_idx(ieot, iiac) < 0 {
+		return ieot + 1, data[ieot : ieot+1], nil // found a EOT (aka Ctrl-D)
+	}
+	if iiac >= 0 {
+		l := 2
+		if (len(data) - iiac) < 1 {
+			return 0, nil, nil // data does not yet contain the telnet command code -> need more data
 		}
+		switch data[iiac+1] {
+		case DONT, DO, WONT, WILL:
+			if (len(data) - iiac) < 2 {
+				return 0, nil, nil // this is a 3-byte command and data does not yet contain the option code -> need more data
+			}
+			l = 3
+		}
+
+		return iiac + l, data[iiac : iiac+l], nil // found a Telnet Command
 	}
-	if err := c.scanner.Err(); err != nil {
-		rhdl.Printf("telnet-ctrl(%s): read command error: %s", c.conn.RemoteAddr(), err)
-	} else {
-		rhdl.Printf("telnet-ctrl(%s): connection closed", c.conn.RemoteAddr())
+	if atEOF {
+		return len(data), dropCR(data), nil // allow last line to have no new line
+	}
+	return 0, nil, nil // we have found none of the escape codes -> need more data
+}
+
+func (c *TelnetClient) handle() {
+	defer func() {
+		if err := c.scanner.Err(); err != nil {
+			rhdl.Printf("telnet-ctrl(%s): read command error: %s", c.conn.RemoteAddr(), err)
+		} else {
+			rhdl.Printf("telnet-ctrl(%s): connection closed", c.conn.RemoteAddr())
+		}
+		c.conn.Close()
+	}()
+
+	c.write_string(prompt)
+	for c.scanner.Scan() {
+		b := c.scanner.Bytes()
+		if len(b) > 0 {
+			switch b[0] {
+			case EOT:
+				return
+			case IAC:
+				if exit := c.handle_iac(c.scanner.Bytes()); exit {
+					return
+				}
+			default:
+				if exit := c.handle_cmd(string(b)); exit {
+					return
+				}
+				c.write_string(prompt)
+			}
+		} else {
+			c.write_string(prompt)
+		}
 	}
 }
 
@@ -370,6 +477,7 @@ func newTelnetClient(conn net.Conn, conf *rhimport.Config, rddb *rhimport.RdDbCh
 	c = &TelnetClient{}
 	c.conn = conn
 	c.scanner = bufio.NewScanner(conn)
+	c.scanner.Split(ScanLinesTelnet)
 	c.writer = bufio.NewWriter(conn)
 	c.conf = conf
 	c.rddb = rddb