netfilter 08/09: xt_time: print timezone for user information

netfilter: xt_time: print timezone for user information

Let users have a way to figure out if their distro set the kernel
timezone at all.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netfilter/xt_time.c

@@ -243,6 +243,17 @@ static struct xt_match xt_time_mt_reg __read_mostly = {
 
 static int __init time_mt_init(void)
 {
+	int minutes = sys_tz.tz_minuteswest;
+
+	if (minutes < 0) /* east of Greenwich */
+		printk(KERN_INFO KBUILD_MODNAME
+		       ": kernel timezone is +%02d%02d\n",
+		       -minutes / 60, -minutes % 60);
+	else /* west of Greenwich */
+		printk(KERN_INFO KBUILD_MODNAME
+		       ": kernel timezone is -%02d%02d\n",
+		       minutes / 60, minutes % 60);
+
 	return xt_register_match(&xt_time_mt_reg);
 }