From: Ralph Corderoy <ralph@inputplus.co.uk>
Date: Fri, 11 Nov 2016 00:38:29 +0000 (+0000)
Subject: dlocaltime(): Only call tzset(3) once.
X-Git-Url: https://diplodocus.org/git/nmh/commitdiff_plain/c762fa39172dee2133e0a5d6324464a4fa3cff50?ds=sidebyside

dlocaltime(): Only call tzset(3) once.

This avoids the stat(2) of /etc/localtime per message scan if TZ isn't
set in the environment;  that's the default case on this Linux system.
I can't see a way the TZ environment variable is likely to change
between messages, or that it's intended an invocation of scan(1), say,
copes with the timezone shifting underneath it by /etc/localtime being
changed.
---

diff --git a/sbr/dtime.c b/sbr/dtime.c
index 066a72d7..89f5dde8 100644
--- a/sbr/dtime.c
+++ b/sbr/dtime.c
@@ -108,7 +108,14 @@ dlocaltime (time_t *clock)
     if (tm->tm_isdst)			/* if DST is in effect */
 	tw.tw_zone -= 60;		/* reset to normal offset */
 #else
-    tzset();
+    {
+        static bool deja_vu;
+
+        if (!deja_vu) {
+            deja_vu = true;
+            tzset();
+        }
+    }
     tw.tw_zone = -(timezone / 60);
 #endif