1 files changed, 84 insertions, 0 deletions
diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c
new file mode 100644
index 0000000000..758163af39
--- /dev/null
+++ b/fs/udf/udftime.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: LGPL-2.0+
+/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Eggert (eggert@twinsun.com). */
+
+/*
+ * dgb 10/02/98: ripped this from glibc source to help convert timestamps
+ *               to unix time
+ *     10/04/98: added new table-based lookup after seeing how ugly
+ *               the gnu code is
+ * blf 09/27/99: ripped out all the old code and inserted new table from
+ *		 John Brockmeyer (without leap second corrections)
+ *		 rewrote udf_stamp_to_time and fixed timezone accounting in
+ *		 udf_time_to_stamp.
+ */
+
+/*
+ * We don't take into account leap seconds. This may be correct or incorrect.
+ * For more NIST information (especially dealing with leap seconds), see:
+ * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
+ */
+
+#include "udfdecl.h"
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+
+void
+udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
+{
+	u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
+	u16 year = le16_to_cpu(src.year);
+	uint8_t type = typeAndTimezone >> 12;
+	int16_t offset;
+
+	if (type == 1) {
+		offset = typeAndTimezone << 4;
+		/* sign extent offset */
+		offset = (offset >> 4);
+		if (offset == -2047) /* unspecified offset */
+			offset = 0;
+	} else
+		offset = 0;
+
+	dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
+			src.second);
+	dest->tv_sec -= offset * 60;
+	dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
+			src.hundredsOfMicroseconds * 100 + src.microseconds);
+	/*
+	 * Sanitize nanosecond field since reportedly some filesystems are
+	 * recorded with bogus sub-second values.
+	 */
+	dest->tv_nsec %= NSEC_PER_SEC;
+}
+
+void
+udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
+{
+	time64_t seconds;
+	int16_t offset;
+	struct tm tm;
+
+	offset = -sys_tz.tz_minuteswest;
+
+	dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
+
+	seconds = ts.tv_sec + offset * 60;
+	time64_to_tm(seconds, 0, &tm);
+	dest->year = cpu_to_le16(tm.tm_year + 1900);
+	dest->month = tm.tm_mon + 1;
+	dest->day = tm.tm_mday;
+	dest->hour = tm.tm_hour;
+	dest->minute = tm.tm_min;
+	dest->second = tm.tm_sec;
+	dest->centiseconds = ts.tv_nsec / 10000000;
+	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
+					dest->centiseconds * 10000) / 100;
+	dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
+			      dest->hundredsOfMicroseconds * 100);
+}
+
+/* EOF */