1 files changed, 72 insertions, 0 deletions
diff --git a/usr.sbin/tcpdump/gmt2local.c b/usr.sbin/tcpdump/gmt2local.c
new file mode 100644
index 00000000000..dd27bc04afd
--- /dev/null
+++ b/usr.sbin/tcpdump/gmt2local.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 1997
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+static const char rcsid[] =
+    "@(#) $Header: /cvs/OpenBSD/src/usr.sbin/tcpdump/gmt2local.c,v 1.1 1999/07/28 20:41:35 jakob Exp $ (LBL)";
+#endif
+
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include <stdio.h>
+#ifdef TIME_WITH_SYS_TIME
+#include <time.h>
+#endif
+
+#include "gnuc.h"
+#ifdef HAVE_OS_PROTO_H
+#include "os-proto.h"
+#endif
+
+#include "gmt2local.h"
+
+/*
+ * Returns the difference between gmt and local time in seconds.
+ * Use gmtime() and localtime() to keep things simple.
+ */
+int32_t
+gmt2local(time_t t)
+{
+	register int dt, dir;
+	register struct tm *gmt, *loc;
+	struct tm sgmt;
+
+	if (t == 0)
+		t = time(NULL);
+	gmt = &sgmt;
+	*gmt = *gmtime(&t);
+	loc = localtime(&t);
+	dt = (loc->tm_hour - gmt->tm_hour) * 60 * 60 +
+	    (loc->tm_min - gmt->tm_min) * 60;
+
+	/*
+	 * If the year or julian day is different, we span 00:00 GMT
+	 * and must add or subtract a day. Check the year first to
+	 * avoid problems when the julian day wraps.
+	 */
+	dir = loc->tm_year - gmt->tm_year;
+	if (dir == 0)
+		dir = loc->tm_yday - gmt->tm_yday;
+	dt += dir * 24 * 60 * 60;
+
+	return (dt);
+}