Check the success of setsockopt

Static analysis (coverity) reported a defect for not checking
the return from setsockopt.  Put in the check, and log if the
setsockopt fails (unlikely).

Fixes coverity 746751 and 746752
(cherry picked from commit 8ec9a2d)

Fixes #11598

Signed-off-by: Stuart Morgan <smorgan@mythtv.org>

mythtv/libs/libmythupnp/httprequest.cpp

@@ -248,7 +248,13 @@ long HTTPRequest::SendResponse( void )
 
 #ifdef USE_SETSOCKOPT
     // Never send out partially complete segments
-    setsockopt( getSocketHandle(), SOL_TCP, TCP_CORK, &g_on, sizeof( g_on ));
+    if (setsockopt(getSocketHandle(), SOL_TCP, TCP_CORK, 
+                   &g_on, sizeof( g_on )) < 0)
+    {
+        LOG(VB_UPNP, LOG_INFO,
+            QString("HTTPRequest::SendResponse(xml/html) "
+                    "setsockopt error setting TCP_CORK on ") + ENO);
+    }
 #endif
 
     // ----------------------------------------------------------------------
@@ -319,7 +325,13 @@ long HTTPRequest::SendResponse( void )
     // ----------------------------------------------------------------------
 
 #ifdef USE_SETSOCKOPT
-    setsockopt( getSocketHandle(), SOL_TCP, TCP_CORK, &g_off, sizeof( g_off ));
+    if (setsockopt(getSocketHandle(), SOL_TCP, TCP_CORK, 
+                   &g_off, sizeof( g_off )) < 0)
+    {
+        LOG(VB_UPNP, LOG_INFO,
+            QString("HTTPRequest::SendResponse(xml/html) "
+                    "setsockopt error setting TCP_CORK off ") + ENO);
+    }
 #endif
 
     return( nBytes );
@@ -357,7 +369,14 @@ long HTTPRequest::SendResponseFile( QString sFileName )
 
 #ifdef USE_SETSOCKOPT
     // Never send out partially complete segments
-    setsockopt( getSocketHandle(), SOL_TCP, TCP_CORK, &g_on, sizeof( g_on ));
+    if (setsockopt(getSocketHandle(), SOL_TCP, TCP_CORK, 
+                   &g_on, sizeof( g_on )) < 0)
+    {
+        LOG(VB_UPNP, LOG_INFO,
+            QString("HTTPRequest::SendResponseFile(%1) "
+                    "setsockopt error setting TCP_CORK on " ).arg(sFileName) +
+            ENO);
+    }
 #endif
 
     QFile tmpFile( sFileName );
@@ -469,7 +488,14 @@ long HTTPRequest::SendResponseFile( QString sFileName )
     // ----------------------------------------------------------------------
 
 #ifdef USE_SETSOCKOPT
-    setsockopt( getSocketHandle(), SOL_TCP, TCP_CORK, &g_off, sizeof( g_off ));
+    if (setsockopt(getSocketHandle(), SOL_TCP, TCP_CORK,
+                   &g_off, sizeof( g_off )) < 0)
+    {
+        LOG(VB_UPNP, LOG_INFO,
+            QString("HTTPRequest::SendResponseFile(%1) "
+                    "setsockopt error setting TCP_CORK off ").arg(sFileName) +
+            ENO);
+    }
 #endif
 
     // -=>TODO: Only returns header length...