Automatically detect kernel and set REUSEPORT #997

Conflicts:
	lib/ProxySQL_GloVars.cpp

lib/ProxySQL_GloVars.cpp

@@ -2,7 +2,7 @@
 #include "proxysql.h"
 #include "cpp.h"
 #include <string>
-
+#include <sys/utsname.h>
 
 
 static void term_handler(int sig) {
@@ -52,12 +52,38 @@ ProxySQL_GlobalVariables::ProxySQL_GlobalVariables() {
 	global.nostart=false;
 	global.foreground=false;
 	global.monitor=true;
-#ifdef SO_REUSEPORT
-	global.reuseport=false;
-#endif /* SO_REUSEPORT */
 #ifdef IDLE_THREADS
 	global.idle_threads=false;
 #endif /* IDLE_THREADS */
+#ifdef SO_REUSEPORT
+	global.reuseport=false;
+#endif /* SO_REUSEPORT */
+	{
+		struct utsname unameData;
+		int rc;
+		rc=uname(&unameData);
+		if (rc==0) {
+			proxy_info("Detected OS: %s\n", unameData.release);
+			//proxy_info("Detected OS: %s %s %s %s %s\n", unameData.sysname, unameData.nodename, unameData.release, unameData.version, unameData.machine);
+#ifdef SO_REUSEPORT
+			if (strcmp(unameData.sysname,"Linux")==0) {
+				int major=0, minor=0, revision=0;
+				sscanf(unameData.release, "%d.%d.%d", &major, &minor, &revision);
+				//fprintf(stderr,"%d %d %d\n",major,minor,revision);
+				if (
+					(major > 3)
+					||
+					(major == 3 && minor >= 9)
+				) {
+					proxy_info("Detected Linux Kernel %d.%d >= 3.9 . Enabling the use of SO_REUSEPORT\n", major, minor);
+					global.reuseport=true;
+				}
+			}
+#endif /* SO_REUSEPORT */
+		} else {
+			proxy_error("ERROR: unable to get information about current kernel\n");
+		}
+	}
 //	global.use_proxysql_mem=false;
 	pthread_mutex_init(&global.start_mutex,NULL);
 #ifdef DEBUG