Teach ntpd(8) how to use socket status to shutdown the daemon. While at

it, remove some verbose shutdown messages that we had before with pipe
close.
ok reyk@

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.143 2016/09/14 13:20:16 rzalamena Exp $ */
+/*	$OpenBSD: ntp.c,v 1.144 2016/09/26 16:55:02 rzalamena Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -425,14 +425,9 @@ ntp_dispatch_imsg(void)
 	struct imsg		 imsg;
 	int			 n;
 
-	if ((n = imsg_read(ibuf_main)) == -1 && errno != EAGAIN)
+	if (((n = imsg_read(ibuf_main)) == -1 && errno != EAGAIN) || n == 0)
 		return (-1);
 
-	if (n == 0) {	/* connection closed */
-		log_warnx("ntp_dispatch_imsg in ntp engine: pipe closed");
-		return (-1);
-	}
-
 	for (;;) {
 		if ((n = imsg_get(ibuf_main, &imsg)) == -1)
 			return (-1);
@@ -477,14 +472,9 @@ ntp_dispatch_imsg_dns(void)
 	struct ntp_addr		*h;
 	int			 n;
 
-	if ((n = imsg_read(ibuf_dns)) == -1)
+	if (((n = imsg_read(ibuf_dns)) == -1 && errno != EAGAIN) || n == 0)
 		return (-1);
 
-	if (n == 0) {	/* connection closed */
-		log_warnx("ntp_dispatch_imsg_dns in ntp engine: pipe closed");
-		return (-1);
-	}
-
 	for (;;) {
 		if ((n = imsg_get(ibuf_dns, &imsg)) == -1)
 			return (-1);

src/usr.sbin/ntpd/ntp_dns.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp_dns.c,v 1.18 2016/09/14 13:20:16 rzalamena Exp $ */
+/*	$OpenBSD: ntp_dns.c,v 1.19 2016/09/26 16:55:02 rzalamena Exp $ */
 
 /*
  * Copyright (c) 2003-2008 Henning Brauer <henning@openbsd.org>
@@ -135,14 +135,9 @@ dns_dispatch_imsg(void)
 	struct ibuf		*buf;
 	const char		*str;
 
-	if ((n = imsg_read(ibuf_dns)) == -1 && errno != EAGAIN)
+	if (((n = imsg_read(ibuf_dns)) == -1 && errno != EAGAIN) || n == 0)
 		return (-1);
 
-	if (n == 0) {	/* connection closed */
-		log_warnx("dispatch_imsg in main: pipe closed");
-		return (-1);
-	}
-
 	for (;;) {
 		if ((n = imsg_get(ibuf_dns, &imsg)) == -1)
 			return (-1);

src/usr.sbin/ntpd/ntpd.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.c,v 1.109 2016/09/14 13:20:16 rzalamena Exp $ */
+/*	$OpenBSD: ntpd.c,v 1.110 2016/09/26 16:55:02 rzalamena Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -41,7 +41,7 @@
 void		sighdlr(int);
 __dead void	usage(void);
 int		main(int, char *[]);
-int		check_child(pid_t, const char *);
+void		check_child(void);
 int		dispatch_imsg(struct ntpd_conf *, const char *, uid_t, gid_t);
 int		dispatch_imsg_ctl(struct ntpd_conf *);
 void		reset_adjtime(void);
@@ -110,7 +110,7 @@ main(int argc, char *argv[])
 {
 	struct ntpd_conf	 lconf;
 	struct pollfd		*pfd = NULL;
-	pid_t			 chld_pid = 0, pid;
+	pid_t			 pid;
 	const char		*conffile;
 	int			 ch, nfds, i, j;
 	int			 pipe_chld[2];
@@ -227,7 +227,7 @@ main(int argc, char *argv[])
 	signal(SIGCHLD, sighdlr);
 
 	/* fork child process */
-	chld_pid = start_child(NTP_PROC_NAME, pipe_chld[1], argc0, argv0);
+	start_child(NTP_PROC_NAME, pipe_chld[1], argc0, argv0);
 
 	log_procinit("[priv]");
 	readfreq();
@@ -315,19 +315,15 @@ main(int argc, char *argv[])
 		}
 
 		if (sigchld) {
-			if (check_child(chld_pid, "child")) {
-				quit = 1;
-				chld_pid = 0;
-			}
+			check_child();
 			sigchld = 0;
 		}
-
 	}
 
 	signal(SIGCHLD, SIG_DFL);
 
-	if (chld_pid)
-		kill(chld_pid, SIGTERM);
+	/* Close socket and start shutdown. */
+	close(ibuf->fd);
 
 	do {
 		if ((pid = wait(NULL)) == -1 &&
@@ -341,36 +337,19 @@ main(int argc, char *argv[])
 	return (0);
 }
 
-int
-check_child(pid_t chld_pid, const char *pname)
+void
+check_child(void)
 {
-	int	 status, sig;
-	char	*signame;
+	int	 status;
 	pid_t	 pid;
 
 	do {
 		pid = waitpid(WAIT_ANY, &status, WNOHANG);
-		if (pid <= 0) {
+		if (pid <= 0)
 			continue;
-		} else if (pid == chld_pid) {
-			if (WIFEXITED(status)) {
-				log_warnx("Lost child: %s exited", pname);
-				return (1);
-			}
-			if (WIFSIGNALED(status)) {
-				sig = WTERMSIG(status);
-				signame = strsignal(sig) ?
-				    strsignal(sig) : "unknown";
-				log_warnx("Lost child: %s terminated; "
-				    "signal %d (%s)", pname, sig, signame);
-				return (1);
-			}
-		} else {
-			priv_constraint_check_child(pid, status);
-		}
-	} while (pid > 0 || (pid == -1 && errno == EINTR));
 
-	return (0);
+		priv_constraint_check_child(pid, status);
+	} while (pid > 0 || (pid == -1 && errno == EINTR));
 }
 
 int
@@ -381,14 +360,9 @@ dispatch_imsg(struct ntpd_conf *lconf, const char *pw_dir,
 	int			 n;
 	double			 d;
 
-	if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
+	if (((n = imsg_read(ibuf)) == -1 && errno != EAGAIN) || n == 0)
 		return (-1);
 
-	if (n == 0) {	/* connection closed */
-		log_warnx("dispatch_imsg in main: pipe closed");
-		return (-1);
-	}
-
 	for (;;) {
 		if ((n = imsg_get(ibuf, &imsg)) == -1)
 			return (-1);