xref: /openbmc/linux/fs/udf/udftime.c (revision be709d48)
1 /* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
2    This file is part of the GNU C Library.
3    Contributed by Paul Eggert (eggert@twinsun.com).
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Library General Public License as
7    published by the Free Software Foundation; either version 2 of the
8    License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Library General Public License for more details.
14 
15    You should have received a copy of the GNU Library General Public
16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18    Boston, MA 02111-1307, USA.  */
19 
20 /*
21  * dgb 10/02/98: ripped this from glibc source to help convert timestamps
22  *               to unix time
23  *     10/04/98: added new table-based lookup after seeing how ugly
24  *               the gnu code is
25  * blf 09/27/99: ripped out all the old code and inserted new table from
26  *		 John Brockmeyer (without leap second corrections)
27  *		 rewrote udf_stamp_to_time and fixed timezone accounting in
28  *		 udf_time_to_stamp.
29  */
30 
31 /*
32  * We don't take into account leap seconds. This may be correct or incorrect.
33  * For more NIST information (especially dealing with leap seconds), see:
34  * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
35  */
36 
37 #include "udfdecl.h"
38 
39 #include <linux/types.h>
40 #include <linux/kernel.h>
41 #include <linux/time.h>
42 
43 void
44 udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
45 {
46 	u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
47 	u16 year = le16_to_cpu(src.year);
48 	uint8_t type = typeAndTimezone >> 12;
49 	int16_t offset;
50 
51 	if (type == 1) {
52 		offset = typeAndTimezone << 4;
53 		/* sign extent offset */
54 		offset = (offset >> 4);
55 		if (offset == -2047) /* unspecified offset */
56 			offset = 0;
57 	} else
58 		offset = 0;
59 
60 	dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
61 			src.second);
62 	dest->tv_sec -= offset * 60;
63 	dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
64 			src.hundredsOfMicroseconds * 100 + src.microseconds);
65 	/*
66 	 * Sanitize nanosecond field since reportedly some filesystems are
67 	 * recorded with bogus sub-second values.
68 	 */
69 	dest->tv_nsec %= NSEC_PER_SEC;
70 }
71 
72 void
73 udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
74 {
75 	time64_t seconds;
76 	int16_t offset;
77 	struct tm tm;
78 
79 	offset = -sys_tz.tz_minuteswest;
80 
81 	dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
82 
83 	seconds = ts.tv_sec + offset * 60;
84 	time64_to_tm(seconds, 0, &tm);
85 	dest->year = cpu_to_le16(tm.tm_year + 1900);
86 	dest->month = tm.tm_mon + 1;
87 	dest->day = tm.tm_mday;
88 	dest->hour = tm.tm_hour;
89 	dest->minute = tm.tm_min;
90 	dest->second = tm.tm_sec;
91 	dest->centiseconds = ts.tv_nsec / 10000000;
92 	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
93 					dest->centiseconds * 10000) / 100;
94 	dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
95 			      dest->hundredsOfMicroseconds * 100);
96 }
97 
98 /* EOF */
99