ping: Don't mix stdio and direct writes

POSIX does not allow mixing direct writes to STDOUT_FILENO with stdio
operations on stdout like we do here.  More importantly, it causes
tests to fail randomly (or not-so-randomly after I added an fflush in
a previous commit).

MFC after:	1 week
Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D57884

2 files changed, 33 insertions, 19 deletions

diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index 19790af083f3..362264ff2428 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -982,8 +982,10 @@ ping(int argc, char *const *argv)
 			(void)clock_gettime(CLOCK_MONOTONIC, &last);
 			if (ntransmitted - nreceived - 1 > nmissedmax) {
 				nmissedmax = ntransmitted - nreceived - 1;
-				if (options & F_MISSED)
-					(void)write(STDOUT_FILENO, &BBELL, 1);
+				if (options & F_MISSED) {
+					(void)putc(BBELL, stdout);
+					(void)fflush(stdout);
+				}
 			}
 		}
 	}
@@ -1084,8 +1086,10 @@ pinger(void)
 	}
 	ntransmitted++;
 	sntransmitted++;
-	if (!(options & F_QUIET) && options & F_DOT)
-		(void)write(STDOUT_FILENO, &DOT[DOTidx++ % DOTlen], 1);
+	if (!(options & F_QUIET) && options & F_DOT) {
+		(void)putc(DOT[DOTidx++ % DOTlen], stdout);
+		(void)fflush(stdout);
+	}
 }
 
 /*
@@ -1207,9 +1211,10 @@ pr_pack(char *buf, ssize_t cc, struct sockaddr_in *from, struct timespec *tv)
 			return;
 		}
 
-		if (options & F_DOT)
-			(void)write(STDOUT_FILENO, &BSPACE, 1);
-		else {
+		if (options & F_DOT) {
+			(void)putc(BSPACE, stdout);
+			(void)fflush(stdout);
+		} else {
 			(void)printf("%zd bytes from %s: icmp_seq=%u", cc,
 			    pr_addr(from->sin_addr), seq);
 			(void)printf(" ttl=%d", ip.ip_ttl);
@@ -1217,8 +1222,10 @@ pr_pack(char *buf, ssize_t cc, struct sockaddr_in *from, struct timespec *tv)
 				(void)printf(" time=%.3f ms", triptime);
 			if (dupflag)
 				(void)printf(" (DUP!)");
-			if (options & F_AUDIBLE)
-				(void)write(STDOUT_FILENO, &BBELL, 1);
+			if (options & F_AUDIBLE) {
+				(void)putc(BBELL, stdout);
+				(void)fflush(stdout);
+			}
 			if (options & F_MASK) {
 				/* Just prentend this cast isn't ugly */
 				(void)printf(" mask=%s",
diff --git a/sbin/ping/ping6.c b/sbin/ping/ping6.c
index 1a4b2472b1bd..c7221cfeae8d 100644
--- a/sbin/ping/ping6.c
+++ b/sbin/ping/ping6.c
@@ -1242,8 +1242,10 @@ ping6(int argc, char *argv[])
 			clock_gettime(CLOCK_MONOTONIC, &last);
 			if (ntransmitted - nreceived - 1 > nmissedmax) {
 				nmissedmax = ntransmitted - nreceived - 1;
-				if (options & F_MISSED)
-					(void)write(STDOUT_FILENO, &BBELL, 1);
+				if (options & F_MISSED) {
+					(void)putc(BBELL, stdout);
+					(void)fflush(stdout);
+				}
 			}
 		}
 	}
@@ -1419,8 +1421,10 @@ pinger(void)
 		(void)printf("ping: wrote %s %d chars, ret=%d\n",
 		    hostname, cc, i);
 	}
-	if (!(options & F_QUIET) && options & F_DOT)
-		(void)write(STDOUT_FILENO, &DOT[DOTidx++ % DOTlen], 1);
+	if (!(options & F_QUIET) && options & F_DOT) {
+		(void)putc(DOT[DOTidx++ % DOTlen], stdout);
+		(void)fflush(stdout);
+	}
 
 	return(0);
 }
@@ -1617,11 +1621,14 @@ pr_pack(u_char *buf, int cc, struct msghdr *mhdr)
 			return;
 		}
 
-		if (options & F_DOT)
-			(void)write(STDOUT_FILENO, &BSPACE, 1);
-		else {
-			if (options & F_AUDIBLE)
-				(void)write(STDOUT_FILENO, &BBELL, 1);
+		if (options & F_DOT) {
+			(void)putc(BSPACE, stdout);
+			(void)fflush(stdout);
+		} else {
+			if (options & F_AUDIBLE) {
+				(void)putc(BBELL, stdout);
+				(void)fflush(stdout);
+			}
 			(void)printf("%d bytes from %s, icmp_seq=%u", cc,
 			    pr_addr(from, fromlen), seq);
 			(void)printf(" hlim=%d", hoplim);
@@ -1810,7 +1817,7 @@ pr_pack(u_char *buf, int cc, struct msghdr *mhdr)
 	}
 
 	if (!(options & F_DOT)) {
-		(void)putchar('\n');
+		(void)putc('\n', stdout);
 		if (options & F_VERBOSE)
 			pr_exthdrs(mhdr);
 		(void)fflush(stdout);