[BusyBox] rdate -a option

[Richard Kojedzinszky]

Hi all.

I made this patch to make rdate accept the -a flag. This makes it not to
step the time immediately, but just skewing it by slowing/fastening the
clock. The code is really copied from the rdate in debian, but I think it
may be useful.

It is for pre9.

Regards,
Kojedzinszky Richard
TvNetWork Rt.
E-mail: krichy at tvnetwork.hu
PGP: 0x24E79141
  Fingerprint = 6847 ECFF EF58 0C09 18A5  16CF 270F 0C6F 24E7 9141
-------------- next part --------------
--- busybox-1.00-pre9/include/usage.h.orig	Wed May  5 15:15:02 2004
+++ busybox-1.00-pre9/include/usage.h	Wed May  5 15:15:47 2004
@@ -1987,12 +1987,13 @@
 	"Example: raid_start /dev/md0 /dev/sdb"
 
 #define rdate_trivial_usage \
-	"[-sp] HOST"
+	"[-spa] HOST"
 #define rdate_full_usage \
 	"Get and possibly set the system date and time from a remote HOST.\n\n" \
 	"Options:\n" \
 	"\t-s\tSet the system date and time (default).\n" \
-	"\t-p\tPrint the date and time."
+	"\t-p\tPrint the date and time.\n" \
+	"\t-a\tSkew the time instead of just hopping it."
 
 #define readlink_trivial_usage \
 	""
--- busybox-1.00-pre9/util-linux/rdate.c.orig	Wed May  5 15:21:01 2004
+++ busybox-1.00-pre9/util-linux/rdate.c	Wed May  5 15:21:59 2004
@@ -81,9 +81,10 @@
 	int opt;
 	int setdate = 1;
 	int printdate = 1;
+	int slidetime = 0;
 
 	/* Interpret command line args */
-	while ((opt = getopt(argc, argv, "sp")) > 0) {
+	while ((opt = getopt(argc, argv, "spa")) > 0) {
 		switch (opt) {
 			case 's':
 				printdate = 0;
@@ -93,6 +94,9 @@
 				printdate = 1;
 				setdate = 0;
 				break;
+			case 'a':
+				slidetime++;
+				break;
 			default:
 				bb_show_usage();
 		}
@@ -109,9 +113,21 @@
 		time(&current_time);
 		if (current_time == remote_time)
 			bb_error_msg("Current time matches remote time.");
-		else
-			if (stime(&remote_time) < 0)
-				bb_perror_msg_and_die("Could not set time of day");
+		else {
+			const char time_errmsg[]="Could not adjust time of day";
+
+			if (!slidetime) {
+				if (stime(&remote_time) < 0)
+					bb_perror_msg_and_die(time_errmsg);
+			} else {
+				struct timeval tv;
+
+				tv.tv_sec = remote_time - current_time;
+				tv.tv_usec = 0;
+				if (adjtime(&tv,NULL) == -1)
+					bb_perror_msg_and_die(time_errmsg);
+			}
+		}
 	}
 
 	if (printdate)