1// SPDX-License-Identifier: LGPL-2.0+
2/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4   Contributed by Paul Eggert (eggert@twinsun.com). */
5
6/*
7 * dgb 10/02/98: ripped this from glibc source to help convert timestamps
8 *               to unix time
9 *     10/04/98: added new table-based lookup after seeing how ugly
10 *               the gnu code is
11 * blf 09/27/99: ripped out all the old code and inserted new table from
12 *		 John Brockmeyer (without leap second corrections)
13 *		 rewrote udf_stamp_to_time and fixed timezone accounting in
14 *		 udf_time_to_stamp.
15 */
16
17/*
18 * We don't take into account leap seconds. This may be correct or incorrect.
19 * For more NIST information (especially dealing with leap seconds), see:
20 * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
21 */
22
23#include "udfdecl.h"
24
25#include <linux/types.h>
26#include <linux/kernel.h>
27#include <linux/time.h>
28
29void
30udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
31{
32	u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
33	u16 year = le16_to_cpu(src.year);
34	uint8_t type = typeAndTimezone >> 12;
35	int16_t offset;
36
37	if (type == 1) {
38		offset = typeAndTimezone << 4;
39		/* sign extent offset */
40		offset = (offset >> 4);
41		if (offset == -2047) /* unspecified offset */
42			offset = 0;
43	} else
44		offset = 0;
45
46	dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
47			src.second);
48	dest->tv_sec -= offset * 60;
49	dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
50			src.hundredsOfMicroseconds * 100 + src.microseconds);
51	/*
52	 * Sanitize nanosecond field since reportedly some filesystems are
53	 * recorded with bogus sub-second values.
54	 */
55	dest->tv_nsec %= NSEC_PER_SEC;
56}
57
58void
59udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
60{
61	time64_t seconds;
62	int16_t offset;
63	struct tm tm;
64
65	offset = -sys_tz.tz_minuteswest;
66
67	dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
68
69	seconds = ts.tv_sec + offset * 60;
70	time64_to_tm(seconds, 0, &tm);
71	dest->year = cpu_to_le16(tm.tm_year + 1900);
72	dest->month = tm.tm_mon + 1;
73	dest->day = tm.tm_mday;
74	dest->hour = tm.tm_hour;
75	dest->minute = tm.tm_min;
76	dest->second = tm.tm_sec;
77	dest->centiseconds = ts.tv_nsec / 10000000;
78	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
79					dest->centiseconds * 10000) / 100;
80	dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
81			      dest->hundredsOfMicroseconds * 100);
82}
83
84/* EOF */
85