Fixed incomplete -x cmd output due to premature ptmx.Close for non-interactive sessions

Signed-off-by: Russ Magee <rmagee@gmail.com>

hkexnet/hkexnet.go

@@ -70,10 +70,9 @@ type (
 
 	// Conn is a connection wrapping net.Conn with KEX & session state
 	Conn struct {
-		kex      KEXAlg      // KEX/KEM proposal (client -> server)
-		m        *sync.Mutex // (internal)
-		c        *net.Conn   // which also implements io.Reader, io.Writer, ...
-		immClose bool
+		kex KEXAlg      // KEX/KEM proposal (client -> server)
+		m   *sync.Mutex // (internal)
+		c   *net.Conn   // which also implements io.Reader, io.Writer, ...
 
 		logCipherText  bool // somewhat expensive, for debugging
 		logPlainText   bool // INSECURE and somewhat expensive, for debugging
@@ -139,10 +138,6 @@ func (hc *Conn) SetStatus(stat CSOType) {
 	log.Println("closeStat:", *hc.closeStat)
 }
 
-func (hc *Conn) SetImmClose() {
-	hc.immClose = true
-}
-
 // ConnOpts returns the cipher/hmac options value, which is sent to the
 // peer but is not itself part of the KEx.
 //
@@ -757,13 +752,7 @@ func (hc *Conn) Close() (err error) {
 	log.Printf("** Writing closeStat %d at Close()\n", *hc.closeStat)
 	//(*hc.c).SetWriteDeadline(time.Now().Add(500 * time.Millisecond))
 	hc.WritePacket(s, CSOExitStatus)
-	// This avoids a bug where server side may not get its last packet of
-	// data through to a client for non-interactive commands which exit
-	// immediately. Avoiding the immediate close lets the client close its
-	// side first.
-	if hc.immClose {
-		err = (*hc.c).Close()
-	}
+	err = (*hc.c).Close()
 	logger.LogDebug(fmt.Sprintln("[Conn Closing]"))
 	return
 }
@@ -1059,7 +1048,6 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 					logger.LogDebug(fmt.Sprintln("[truncated payload, cannot determine CSOExitStatus]"))
 					hc.SetStatus(CSETruncCSO)
 				}
-				hc.SetImmClose() // clients can immediately close their end
 				hc.Close()
 			} else if ctrlStatOp == CSOTunSetup {
 				// server side tunnel setup in response to client

hkexshd/hkexshd.go

@@ -405,7 +405,9 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, conn *hkexnet.C
 			// Background jobs still may be running; close the
 			// pty anyway, so the client can return before
 			// wg.Wait() below completes (Issue #18)
-			_ = ptmx.Close()
+			if interactive {
+				_ = ptmx.Close()
+			}
 		}
 		wg.Wait() // Wait on pty->stdout completion to client
 	}