From NetBSD:

fix pr/1226 from David Gluss: allow rdate to use adjtime(2)

2 files changed, 57 insertions, 19 deletions

diff --git a/usr.sbin/rdate/rdate.8 b/usr.sbin/rdate/rdate.8
index 5a6b37b06f5..c3f352c5282 100644
--- a/usr.sbin/rdate/rdate.8
+++ b/usr.sbin/rdate/rdate.8
@@ -27,7 +27,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\"	$Id: rdate.8,v 1.1 1995/10/18 08:48:04 deraadt Exp $
+.\"	$Id: rdate.8,v 1.2 1996/02/22 00:17:04 niklas Exp $
 .\"
 .Dd April 30, 1994
 .Dt RDATE 8
@@ -37,14 +37,14 @@
 .Nd set the system's date from a remote host
 .Sh SYNOPSIS
 .Nm rdate
-.Op Fl ps
+.Op Fl psa
 .Ar host 
 .Sh DESCRIPTION
 .Nm Rdate
 displays and sets the local date and time from the
 host name or address given as the argument. It uses the RFC868
 protocol which is usually implemented as a built-in service of
-.Xr inetd(1).
+.Xr inetd 1
 .Pp
 Available options:
 .Pp
@@ -53,5 +53,11 @@ Available options:
 Do not set, just print the remote time
 .It Fl s
 Do not print the time.
+.It Fl a
+Use the 
+.Xr adjtime 2
+call to gradually skew the local time to the
+remote time rather than just hopping.
 .Sh SEE ALSO
 .Xr inetd 1
+.Xr adjtime 2
diff --git a/usr.sbin/rdate/rdate.c b/usr.sbin/rdate/rdate.c
index f1adbe1ebdf..d195f5934db 100644
--- a/usr.sbin/rdate/rdate.c
+++ b/usr.sbin/rdate/rdate.c
@@ -27,7 +27,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: rdate.c,v 1.1 1995/10/18 08:48:04 deraadt Exp $
+ *	$Id: rdate.c,v 1.2 1996/02/22 00:17:06 niklas Exp $
  */
 
 /*
@@ -38,7 +38,7 @@
  *	midnight January 1st 1900.
  */
 #ifndef lint
-static char rcsid[] = "$Id: rdate.c,v 1.1 1995/10/18 08:48:04 deraadt Exp $";
+static char rcsid[] = "$Id: rdate.c,v 1.2 1996/02/22 00:17:06 niklas Exp $";
 #endif				/* lint */
 
 #include <sys/types.h>
@@ -58,23 +58,35 @@ static char rcsid[] = "$Id: rdate.c,v 1.1 1995/10/18 08:48:04 deraadt Exp $";
 #define DIFFERENCE 2208988800
 #endif
 
+extern char    *__progname;
+
+static void
+usage()
+{
+	(void) fprintf(stderr, "Usage: %s [-psa] host\n", __progname);
+	(void) fprintf(stderr, "  -p: just print, don't set\n");
+	(void) fprintf(stderr, "  -s: just set, don't print\n");
+	(void) fprintf(stderr, "  -a: use adjtime instead of instant change\n");
+}
+
 int
 main(argc, argv)
 	int             argc;
 	char           *argv[];
 {
 	int             pr = 0, silent = 0, s;
+	int		slidetime = 0;
+	int		adjustment;
 	time_t          tim;
 	char           *hname;
 	struct hostent *hp;
 	struct protoent *pp, ppp;
 	struct servent *sp, ssp;
 	struct sockaddr_in sa;
-	extern char    *__progname;
 	extern int      optind;
 	int             c;
 
-	while ((c = getopt(argc, argv, "ps")) != -1)
+	while ((c = getopt(argc, argv, "psa")) != -1)
 		switch (c) {
 		case 'p':
 			pr++;
@@ -84,21 +96,25 @@ main(argc, argv)
 			silent++;
 			break;
 
+		case 'a':
+			slidetime++;
+			break;
+
 		default:
-			goto usage;
+			usage();
+			return 1;
 		}
 
 	if (argc - 1 != optind) {
-usage:
-		(void) fprintf(stderr, "Usage: %s [-ps] host\n", __progname);
-		return (1);
+		usage();
+		return 1;
 	}
 	hname = argv[optind];
 
 	if ((hp = gethostbyname(hname)) == NULL) {
-		fprintf(stderr, "%s: ", __progname);
+		(void) fprintf(stderr, "%s: ", __progname);
 		herror(hname);
-		exit(1);
+		return 1;
 	}
 
 	if ((sp = getservbyname("time", "tcp")) == NULL) {
@@ -129,13 +145,29 @@ usage:
 	tim = ntohl(tim) - DIFFERENCE;
 
 	if (!pr) {
-		struct timeval  tv;
-		tv.tv_sec = tim;
-		tv.tv_usec = 0;
-		if (settimeofday(&tv, NULL) == -1)
-			err(1, "Could not set time of day");
+	    struct timeval  tv;
+	    if (!slidetime) {
+		    tv.tv_sec = tim;
+		    tv.tv_usec = 0;
+		    if (settimeofday(&tv, NULL) == -1)
+			    err(1, "Could not set time of day");
+	    } else {
+		    struct timeval tv_current;
+		    if (gettimeofday(&tv_current, NULL) == -1)
+			    err(1, "Could not get local time of day");
+		    adjustment = tv.tv_sec = tim - tv_current.tv_sec;
+		    tv.tv_usec = 0;
+		    if (adjtime(&tv, NULL) == -1)
+			    err(1, "Could not adjust time of day");
+	    }
 	}
-	if (!silent)
+
+	if (!silent) {
 		(void) fputs(ctime(&tim), stdout);
+		if (slidetime)
+		    (void) fprintf(stdout, 
+				   "%s: adjust local clock by %d seconds\n",
+				   adjustment);
+	}
 	return 0;
 }