fs/udf/udftime.c

   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
  29 void
  30 udf_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
  50         /*
  51          * Sanitize nanosecond field since reportedly some filesystems are
  52          * recorded with bogus sub-second values.
  53          */
  54         if (src.centiseconds < 100 && src.hundredsOfMicroseconds < 100 &&
  55             src.microseconds < 100) {
  56                 dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
  57                         src.hundredsOfMicroseconds * 100 + src.microseconds);
  58         } else {
  59                 dest->tv_nsec = 0;
  60         }
  61 }
  62
  63 void
  64 udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts)
  65 {
  66         time64_t seconds;
  67         int16_t offset;
  68         struct tm tm;
  69
  70         offset = -sys_tz.tz_minuteswest;
  71
  72         dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
  73
  74         seconds = ts.tv_sec + offset * 60;
  75         time64_to_tm(seconds, 0, &tm);
  76         dest->year = cpu_to_le16(tm.tm_year + 1900);
  77         dest->month = tm.tm_mon + 1;
  78         dest->day = tm.tm_mday;
  79         dest->hour = tm.tm_hour;
  80         dest->minute = tm.tm_min;
  81         dest->second = tm.tm_sec;
  82         dest->centiseconds = ts.tv_nsec / 10000000;
  83         dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
  84                                         dest->centiseconds * 10000) / 100;
  85         dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
  86                               dest->hundredsOfMicroseconds * 100);
  87 }
  88
  89 /* EOF */