b24413180f560 (Greg Kroah-Hartman 2017-11-01 15:07:57 +0100 1) // SPDX-License-Identifier: GPL-2.0
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 2) /*
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 3) * linux/fs/isofs/util.c
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 4) */
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 5)
e4a93be6cb281 (Oscar Forner Martinez 2015-01-06 16:54:19 -0800 6) #include <linux/time.h>
94f2f715771d0 (Al Viro 2005-04-25 18:32:12 -0700 7) #include "isofs.h"
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 8)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 9) /*
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 10) * We have to convert from a MM/DD/YY format to the Unix ctime format.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 11) * We have to take into account leap years and all of that good stuff.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 12) * Unfortunately, the kernel does not have the information on hand to
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 13) * take into account daylight savings time, but it shouldn't matter.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 14) * The time stored should be localtime (with or without DST in effect),
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 15) * and the timezone offset should hold the offset required to get back
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 16) * to GMT. Thus we should always be correct.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 17) */
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 18)
34be4dbf87fc3 (Arnd Bergmann 2017-10-19 16:47:48 +0200 19) int iso_date(u8 *p, int flag)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 20) {
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 21) int year, month, day, hour, minute, second, tz;
e4a93be6cb281 (Oscar Forner Martinez 2015-01-06 16:54:19 -0800 22) int crtime;
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 23)
e4a93be6cb281 (Oscar Forner Martinez 2015-01-06 16:54:19 -0800 24) year = p[0];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 25) month = p[1];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 26) day = p[2];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 27) hour = p[3];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 28) minute = p[4];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 29) second = p[5];
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 30) if (flag == 0) tz = p[6]; /* High sierra has no time zone */
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 31) else tz = 0;
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 32)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 33) if (year < 0) {
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 34) crtime = 0;
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 35) } else {
e4a93be6cb281 (Oscar Forner Martinez 2015-01-06 16:54:19 -0800 36) crtime = mktime64(year+1900, month, day, hour, minute, second);
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 37)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 38) /* sign extend */
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 39) if (tz & 0x80)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 40) tz |= (-1 << 8);
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 41)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 42) /*
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 43) * The timezone offset is unreliable on some disks,
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 44) * so we make a sanity check. In no case is it ever
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 45) * more than 13 hours from GMT, which is 52*15min.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 46) * The time is always stored in localtime with the
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 47) * timezone offset being what get added to GMT to
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 48) * get to localtime. Thus we need to subtract the offset
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 49) * to get to true GMT, which is what we store the time
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 50) * as internally. On the local system, the user may set
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 51) * their timezone any way they wish, of course, so GMT
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 52) * gets converted back to localtime on the receiving
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 53) * system.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 54) *
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 55) * NOTE: mkisofs in versions prior to mkisofs-1.10 had
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 56) * the sign wrong on the timezone offset. This has now
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 57) * been corrected there too, but if you are getting screwy
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 58) * results this may be the explanation. If enough people
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 59) * complain, a user configuration option could be added
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 60) * to add the timezone offset in with the wrong sign
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 61) * for 'compatibility' with older discs, but I cannot see how
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 62) * it will matter that much.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 63) *
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 64) * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 65) * for pointing out the sign error.
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 66) */
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 67) if (-52 <= tz && tz <= 52)
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 68) crtime -= tz * 15 * 60;
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 69) }
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 70) return crtime;
^1da177e4c3f4 (Linus Torvalds 2005-04-16 15:20:36 -0700 71) }
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