syslogd: re-read the timezone when receive a SIGHUP.

syslogd already re-reads the configuration file and the hostname when
receiving a SIGHUP, so it makes sense to reset the timezone.
Special care was taken to ensure we don't break installations running
with a custom TZ variable.

PR:		196905
Submitted by:	Kurt Lidl <lidl pix.net>
Sponsored by:	Pi-Coral, Inc.

1 files changed, 18 insertions, 0 deletions

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index 9ffe797..ff3e524 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -1603,6 +1603,24 @@ init(int signo)
 	}
 
 	/*
+	 * Load / reload timezone data (in case it changed).
+	 *
+	 * Just calling tzset() again does not work, the timezone code
+	 * caches the result.  However, by setting the TZ variable, one
+	 * can defeat the caching and have the timezone code really
+	 * reload the timezone data.  Respect any initial setting of
+	 * TZ, in case the system is configured specially.
+	 */
+	dprintf("loading timezone data via tzset()\n");
+	if (getenv("TZ")) {
+		tzset();
+	} else {
+		setenv("TZ", ":/etc/localtime", 1);
+		tzset();
+		unsetenv("TZ");
+	}
+
+	/*
 	 *  Close all open log files.
 	 */
 	Initialized = 0;