From 25c2756a82ad480edc3b37cdd6ae0154518af0a4 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Mon, 10 Sep 2018 12:13:18 -0600
Subject: [PATCH] apps/examples/tcpblaster:  Add an option to use poll() to
 pace input or output.

---
 examples/tcpblaster/Kconfig             | 20 ++++++++++++++++++++
 examples/tcpblaster/tcpblaster_client.c | 25 +++++++++++++++++++++++++
 examples/tcpblaster/tcpblaster_server.c | 25 +++++++++++++++++++++++++
 3 files changed, 70 insertions(+)

diff --git a/examples/tcpblaster/Kconfig b/examples/tcpblaster/Kconfig
index ee6612fa3..87479eda9 100644
--- a/examples/tcpblaster/Kconfig
+++ b/examples/tcpblaster/Kconfig
@@ -35,6 +35,26 @@ config EXAMPLES_TCPBLASTER_PRIORITY1
 	int "Target1 priority"
 	default 100
 
+config EXAMPLES_TCPBLASTER_POLLOUT
+	bool "Use poll() to pace output"
+	default n
+	depends on !DISABLE_POLL
+	---help---
+		Client will use poll() to verify that send() will not block.  This
+		does not improve performance (in fact, it will degrade perform
+		slightly).  But it is useful for verifying that poll() can be used
+		to pace output.
+
+config EXAMPLES_TCPBLASTER_POLLIN
+	bool "Use poll() to pace input"
+	default n
+	depends on !DISABLE_POLL
+	---help---
+		Client will use poll() to verify that recv() will not block.  This
+		does not improve performance (in fact, it will degrade perform
+		slightly).  But it is useful for verifying that poll() can be used
+		to pace input.
+
 config EXAMPLES_TCPBLASTER_LOOPBACK
 	bool "Loopback test"
 	default n
diff --git a/examples/tcpblaster/tcpblaster_client.c b/examples/tcpblaster/tcpblaster_client.c
index 8407335c3..0de331bfe 100644
--- a/examples/tcpblaster/tcpblaster_client.c
+++ b/examples/tcpblaster/tcpblaster_client.c
@@ -46,6 +46,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <time.h>
+#include <poll.h>
 #include <string.h>
 #include <errno.h>
 
@@ -147,6 +148,30 @@ void tcpblaster_client(void)
 
   for (; ; )
     {
+#ifdef CONFIG_EXAMPLES_TCPBLASTER_POLLOUT
+      struct pollfd fds[1];
+      int ret;
+
+      memset(fds, 0, 1 * sizeof(struct pollfd));
+      fds[0].fd     = sockfd;
+      fds[0].events = POLLOUT | POLLHUP;
+
+      /* Wait until we can send data or until the connection is lost */
+
+      ret = poll(fds, 1, -1);
+      if (ret < 0)
+        {
+          printf("client: ERROR poll failed: %d\n", errno);
+          goto errout_with_socket;
+        }
+
+      if ((fds[0].revents & POLLHUP) != 0)
+        {
+          printf("client: WARNING poll returned POLLHUP\n");
+          goto errout_with_socket;
+        }
+#endif
+
       nbytessent = send(sockfd, outbuf, SENDSIZE, 0);
       if (nbytessent < 0)
         {
diff --git a/examples/tcpblaster/tcpblaster_server.c b/examples/tcpblaster/tcpblaster_server.c
index b974918c6..2de06722d 100644
--- a/examples/tcpblaster/tcpblaster_server.c
+++ b/examples/tcpblaster/tcpblaster_server.c
@@ -41,6 +41,7 @@
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <poll.h>
 #include <netinet/in.h>
 
 #include <stdio.h>
@@ -187,6 +188,30 @@ void tcpblaster_server(void)
 
   for (; ; )
     {
+#ifdef CONFIG_EXAMPLES_TCPBLASTER_POLLIN
+      struct pollfd fds[1];
+      int ret;
+
+      memset(fds, 0, 1 * sizeof(struct pollfd));
+      fds[0].fd     = acceptsd;
+      fds[0].events = POLLIN | POLLHUP;
+
+      /* Wait until we can receive data or until the connection is lost */
+
+      ret = poll(fds, 1, -1);
+      if (ret < 0)
+        {
+          printf("server: ERROR poll failed: %d\n", errno);
+          goto errout_with_acceptsd;
+        }
+
+      if ((fds[0].revents & POLLHUP) != 0)
+        {
+          printf("server: WARNING poll returned POLLHUP\n");
+          goto errout_with_acceptsd;
+        }
+#endif
+
       nbytesread = recv(acceptsd, buffer, SENDSIZE, 0);
       if (nbytesread < 0)
         {