Yet another repair for the previouis botched recvfrom() fix; Fix telnet driver: It needs to break out of the read loop if 0 (meaning not conneced) of a value < 0 (an error) is encountered.

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5541 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog.txt

@@ -490,3 +490,5 @@
 	* apps/builtin/: Extensions from Mike Smith.
 	* apps/examples/ftpd/Makefile: Name ftpd_start is not the name of
 	  the entrypoint.  Should be ftpd_main (from Yan T.)
+	* apps/netutils/telnetd/telnetd_driver: Was stuck in a loop if
+	  recv[from]() ever returned a value <= 0.

netutils/telnetd/telnetd_driver.c

@@ -558,6 +558,8 @@ static ssize_t telnetd_read(FAR struct file *filep, FAR char *buffer, size_t len
     {
       if (priv->td_pending > 0)
         {
+          /* Process the buffered telnet data */
+
           FAR const char *src = &priv->td_rxbuffer[priv->td_offset];
           ret = telnetd_receive(priv, src, priv->td_pending, buffer, len);
         }
@@ -568,13 +570,25 @@ static ssize_t telnetd_read(FAR struct file *filep, FAR char *buffer, size_t len
         {
           ret = psock_recv(&priv->td_psock, priv->td_rxbuffer,
                           CONFIG_TELNETD_RXBUFFER_SIZE, 0);
+
+          /* Did we receive anything? */
+
           if (ret > 0)
             {
-              /* Process the received telnet data */
+              /* Yes.. Process the newly received telnet data */
 
               telnetd_dumpbuffer("Received buffer", priv->td_rxbuffer, ret);
               ret = telnetd_receive(priv, priv->td_rxbuffer, ret, buffer, len);
            }
+
+          /* Otherwise the peer closed the connection (ret == 0) or an error
+           * occurred (ret < 0).
+           */
+
+          else
+            {
+              break;
+            }
         }
     }
   while (ret == 0);