Excessive debugging off; client logout (exit) causing panic on server-side, debug TBD

demo/server/server.go

@@ -9,7 +9,6 @@ import (
 	"os"
 	"os/exec"
 	"os/user"
-	"strings"
 	"syscall"
 
 	hkex "blitter.com/hkexsh"
@@ -27,7 +26,8 @@ type cmdSpec struct {
 
 /* -------------------------------------------------------------- */
 
-// Run a command (via os.exec) as a specific user
+/*
+ // Run a command (via os.exec) as a specific user
 //
 // Uses ptys to support commands which expect a terminal.
 func runCmdAs(who string, cmd string, conn hkex.Conn) (err error) {
@@ -66,6 +66,7 @@ func runCmdAs(who string, cmd string, conn hkex.Conn) (err error) {
 	}
 	return
 }
+*/
 
 // Run a command (via default shell) as a specific user
 //
@@ -111,8 +112,11 @@ func runShellAs(who string, cmd string, interactive bool, conn hkex.Conn) (err e
 	}
 	// Make sure to close the pty at the end.
 	defer func() { _ = ptmx.Close() }() // Best effort.
-	// Copy stdin to the pty and the pty to stdout.
-	go func() { _, _ = io.Copy(ptmx, conn) }()
+	// Copy stdin to the pty.. (bgnd goroutine)
+	go func() {
+		_, _ = io.Copy(ptmx, conn)
+	}()
+	// ..and the pty to stdout.
 	_, _ = io.Copy(conn, ptmx)
 
 	//err = c.Run()  // returns when c finishes.
@@ -176,10 +180,10 @@ func main() {
 			//passed down to the command handlers.
 			var rec cmdSpec
 			var len1, len2, len3, len4 uint32
-			
+
 			n, err := fmt.Fscanf(c, "%d %d %d %d\n", &len1, &len2, &len3, &len4)
 			log.Printf("cmdSpec read:%d %d %d %d\n", len1, len2, len3, len4)
-			
+
 			if err != nil || n < 4 {
 				log.Println("[Bad cmdSpec fmt]")
 				return err

hkexnet.go

@@ -299,10 +299,10 @@ func (hl HKExListener) Accept() (hc Conn, err error) {
 // See go doc io.Reader
 func (c Conn) Read(b []byte) (n int, err error) {
 	//log.Printf("[Decrypting...]\r\n")
-	//log.Printf("Read() requests %d bytes\n", len(b))
+	log.Printf("Read() requests %d bytes\n", len(b))
 	for {
 		//log.Printf("c.dBuf.Len(): %d\n", c.dBuf.Len())
-		if c.dBuf.Len() >= 1 /* len(b) */ {
+		if c.dBuf.Len() > 0 /* len(b) */ {
 			break
 		}
 
@@ -311,13 +311,21 @@ func (c Conn) Read(b []byte) (n int, err error) {
 
 		// Read the hmac LSB and payload len first
 		err = binary.Read(c.c, binary.BigEndian, &hmacIn)
-		if err != nil && err.Error() != "EOF" {
-			panic(err)
+		if err != nil {
+			if err.Error() != "EOF" {
+				log.Println("Error was:", err.Error())
+			} else {
+				return 0, err
+			}
 		}
 
 		err = binary.Read(c.c, binary.BigEndian, &payloadLen)
 		if err != nil {
+			//			if err.Error() != "EOF" {
 			panic(err)
+			//			} else {
+			//				return 0, err
+			//			}
 		}
 		if payloadLen > 16384 {
 			panic("Insane payloadLen")
@@ -359,10 +367,15 @@ func (c Conn) Read(b []byte) (n int, err error) {
 		hTmp := c.rm.Sum(nil)[0]
 		log.Printf("<%04x) HMAC:(i)%02x (c)%02x\r\n", decryptN, hmacIn, hTmp)
 	}
-	//log.Printf("Read() got %d bytes\n", c.dBuf.Len())
-	copy(b, c.dBuf.Next(len(b)))
+	retN := c.dBuf.Len()
+	if retN > len(b) {
+		retN = len(b)
+	}
+
+	log.Printf("Read() got %d bytes\n", retN)
+	copy(b, c.dBuf.Next(retN))
 	//log.Printf("As Read() returns, c.dBuf is %d long: %s\n", c.dBuf.Len(), hex.Dump(c.dBuf.Bytes()))
-	return len(b), nil
+	return retN, nil
 }
 
 // Write a byte slice