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: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/net/netfilter/xt_time.c b/net/netfilter/xt_time.c
index 29375ba8db73..93acaa59d108 100644
--- a/net/netfilter/xt_time.c
+++ b/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);
 }