--- embedaddon/mtr/select.c	2013/07/21 23:43:41	1.1.1.1
+++ embedaddon/mtr/select.c	2016/11/01 09:33:48	1.1.1.2
@@ -16,7 +16,8 @@
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
-#include <config.h>
+#include "config.h"
+
 #include <sys/types.h>
 #include <sys/time.h>
 #include <stdlib.h>
@@ -29,12 +30,10 @@
 #include <errno.h>
 
 #include "mtr.h"
-#include "display.h"
 #include "dns.h"
 #include "net.h"
-#ifndef NO_IPINFO
 #include "asn.h"
-#endif
+#include "display.h"
 
 extern int Interactive;
 extern int MaxPing;
@@ -47,6 +46,8 @@ static struct timeval intervaltime;
 int display_offset = 0;
 
 
+#define GRACETIME (5 * 1000*1000)
+
 void select_loop(void) {
   fd_set readfd;
   fd_set writefd;
@@ -59,9 +60,13 @@ void select_loop(void) {
   int NumPing = 0;
   int paused = 0;
   struct timeval lasttime, thistime, selecttime;
+  struct timeval startgrace;
   int dt;
   int rv; 
+  int graceperiod = 0;
 
+  memset(&startgrace, 0, sizeof(startgrace));
+
   gettimeofday(&lasttime, NULL);
 
   while(1) {
@@ -82,8 +87,12 @@ void select_loop(void) {
 #ifdef ENABLE_IPV6
     if (dns) {
       dnsfd6 = dns_waitfd6();
-      FD_SET(dnsfd6, &readfd);
-      if(dnsfd6 >= maxfd) maxfd = dnsfd6 + 1;
+      if (dnsfd6 >= 0) {
+        FD_SET(dnsfd6, &readfd);
+        if(dnsfd6 >= maxfd) maxfd = dnsfd6 + 1;
+      } else {
+        dnsfd6 = 0;
+      }
     } else
       dnsfd6 = 0;
 #endif
@@ -103,8 +112,13 @@ void select_loop(void) {
 
     do {
       if(anyset || paused) {
+	/* Set timeout to 0.1s.
+	 * While this is almost instantaneous for human operators,
+	 * it's slow enough for computers to go do something else;
+	 * this prevents mtr from hogging 100% CPU time on one core.
+	 */
 	selecttime.tv_sec = 0;
-	selecttime.tv_usec = 0;
+	selecttime.tv_usec = paused?100000:0; 
       
 	rv = select(maxfd, (void *)&readfd, &writefd, NULL, &selecttime);
 
@@ -117,10 +131,24 @@ void select_loop(void) {
 	   (thistime.tv_sec == lasttime.tv_sec + intervaltime.tv_sec &&
 	    thistime.tv_usec >= lasttime.tv_usec + intervaltime.tv_usec)) {
 	  lasttime = thistime;
-	  if(NumPing >= MaxPing && (!Interactive || ForceMaxPing))
+
+	  if (!graceperiod) {
+	    if (NumPing >= MaxPing && (!Interactive || ForceMaxPing)) {
+	      graceperiod = 1;
+	      startgrace = thistime;
+	    }
+
+	    /* do not send out batch when we've already initiated grace period */
+	    if (!graceperiod && net_send_batch())
+	      NumPing++;
+	  }
+	}
+
+	if (graceperiod) {
+	  dt = (thistime.tv_usec - startgrace.tv_usec) +
+		    1000000 * (thistime.tv_sec - startgrace.tv_sec);
+	  if (dt > GRACETIME)
 	    return;
-	  if (net_send_batch())
-	    NumPing++;
 	}
 
 	selecttime.tv_usec = (thistime.tv_usec - lasttime.tv_usec);
@@ -169,12 +197,12 @@ void select_loop(void) {
 
     /*  Have we finished a nameservice lookup?  */
 #ifdef ENABLE_IPV6
-    if(dns && FD_ISSET(dnsfd6, &readfd)) {
+    if(dns && dnsfd6 && FD_ISSET(dnsfd6, &readfd)) {
       dns_ack6();
       anyset = 1;
     }
 #endif
-    if(dns && FD_ISSET(dnsfd, &readfd)) {
+    if(dns && dnsfd && FD_ISSET(dnsfd, &readfd)) {
       dns_ack();
       anyset = 1;
     }
@@ -210,7 +238,7 @@ void select_loop(void) {
 	  display_clear();
 	}
 	break;
-#ifndef NO_IPINFO
+#ifdef IPINFO
       case ActionII:
 	if (ipinfo_no >= 0) {
 	  ipinfo_no++;