ping: fix dead loop problem

This change will make ping exit normally when system clock is changed during
time time when ping runs, and more imporatntly the is set before start time.
Earlier that caused infinite loop.

Fixes: #276

ping/ping.h

@@ -163,7 +163,7 @@ struct ping_rts {
 	int preload;
 	int deadline;			/* time to die */
 	int lingertime;
-	struct timeval start_time, cur_time;
+	struct timespec start_time, cur_time;
 	volatile int exiting;
 	volatile int status_snapshot;
 	int confirm;
@@ -294,6 +294,20 @@ static inline void tvsub(struct timeval *out, struct timeval *in)
 	out->tv_sec -= in->tv_sec;
 }
 
+/*
+ * tssub --
+ *	Subtract 2 timespec structs:  out = out - in.  Out is assumed to
+ * be >= in.
+ */
+static inline void tssub(struct timespec *out, struct timespec *in)
+{
+	if ((out->tv_nsec -= in->tv_nsec) < 0) {
+		--out->tv_sec;
+		out->tv_nsec += 1000000000;
+	}
+	out->tv_sec -= in->tv_sec;
+}
+
 static inline void set_signal(int signo, void (*handler)(int))
 {
 	struct sigaction sa;

ping/ping_common.c

@@ -313,15 +313,15 @@ int pinger(struct ping_rts *rts, ping_func_set_st *fset, socket_st *sock)
 
 	/* Check that packets < rate*time + preload */
 	if (rts->cur_time.tv_sec == 0) {
-		gettimeofday(&rts->cur_time, NULL);
+		clock_gettime(CLOCK_MONOTONIC_RAW, &rts->cur_time);
 		tokens = rts->interval * (rts->preload - 1);
 	} else {
 		long ntokens, tmp;
-		struct timeval tv;
+		struct timespec tv;
 
-		gettimeofday(&tv, NULL);
+		clock_gettime(CLOCK_MONOTONIC_RAW, &tv);
 		ntokens = (tv.tv_sec - rts->cur_time.tv_sec) * 1000 +
-			  (tv.tv_usec - rts->cur_time.tv_usec) / 1000;
+			  (tv.tv_nsec - rts->cur_time.tv_nsec) / 1000000;
 		if (!rts->interval) {
 			/* Case of unlimited flood is special;
 			 * if we see no reply, they are limited to 100pps */
@@ -531,7 +531,7 @@ void setup(struct ping_rts *rts, socket_st *sock)
 	sigemptyset(&sset);
 	sigprocmask(SIG_SETMASK, &sset, NULL);
 
-	gettimeofday(&rts->start_time, NULL);
+	clock_gettime(CLOCK_MONOTONIC_RAW, &rts->start_time);
 
 	if (rts->deadline) {
 		struct itimerval it;
@@ -868,10 +868,10 @@ static long llsqrt(long long a)
  */
 int finish(struct ping_rts *rts)
 {
-	struct timeval tv = rts->cur_time;
+	struct timespec tv = rts->cur_time;
 	char *comma = "";
 
-	tvsub(&tv, &rts->start_time);
+	tssub(&tv, &rts->start_time);
 
 	putchar('\n');
 	fflush(stdout);
@@ -891,7 +891,7 @@ int finish(struct ping_rts *rts)
 #endif
 		printf(_(", %g%% packet loss"),
 		       (float)((((long long)(rts->ntransmitted - rts->nreceived)) * 100.0) / rts->ntransmitted));
-		printf(_(", time %ldms"), 1000 * tv.tv_sec + (tv.tv_usec + 500) / 1000);
+		printf(_(", time %ldms"), 1000 * tv.tv_sec + (tv.tv_nsec + 500000) / 1000000);
 	}
 
 	putchar('\n');
@@ -924,7 +924,7 @@ int finish(struct ping_rts *rts)
 	}
 
 	if (rts->nreceived && (!rts->interval || rts->opt_flood || rts->opt_adaptive) && rts->ntransmitted > 1) {
-		int ipg = (1000000 * (long long)tv.tv_sec + tv.tv_usec) / (rts->ntransmitted - 1);
+		int ipg = (1000000 * (long long)tv.tv_sec + tv.tv_nsec / 1000) / (rts->ntransmitted - 1);
 
 		printf(_("%sipg/ewma %d.%03d/%d.%03d ms"),
 		       comma, ipg / 1000, ipg % 1000, rts->rtt / 8000, (rts->rtt / 8) % 1000);