2 * linux/fs/isofs/util.c
5 #include <linux/time.h>
6 #include <linux/iso_fs.h>
9 * We have to convert from a MM/DD/YY format to the Unix ctime format.
10 * We have to take into account leap years and all of that good stuff.
11 * Unfortunately, the kernel does not have the information on hand to
12 * take into account daylight savings time, but it shouldn't matter.
13 * The time stored should be localtime (with or without DST in effect),
14 * and the timezone offset should hold the offset required to get back
15 * to GMT. Thus we should always be correct.
18 int iso_date(char * p, int flag)
20 int year, month, day, hour, minute, second, tz;
29 if (flag == 0) tz = p[6]; /* High sierra has no time zone */
35 int monlen[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
40 for (i = 1; i < month; i++)
42 if (((year+2) % 4) == 0 && month > 2)
45 crtime = ((((days * 24) + hour) * 60 + minute) * 60)
53 * The timezone offset is unreliable on some disks,
54 * so we make a sanity check. In no case is it ever
55 * more than 13 hours from GMT, which is 52*15min.
56 * The time is always stored in localtime with the
57 * timezone offset being what get added to GMT to
58 * get to localtime. Thus we need to subtract the offset
59 * to get to true GMT, which is what we store the time
60 * as internally. On the local system, the user may set
61 * their timezone any way they wish, of course, so GMT
62 * gets converted back to localtime on the receiving
65 * NOTE: mkisofs in versions prior to mkisofs-1.10 had
66 * the sign wrong on the timezone offset. This has now
67 * been corrected there too, but if you are getting screwy
68 * results this may be the explanation. If enough people
69 * complain, a user configuration option could be added
70 * to add the timezone offset in with the wrong sign
71 * for 'compatibility' with older discs, but I cannot see how
72 * it will matter that much.
74 * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann)
75 * for pointing out the sign error.
77 if (-52 <= tz && tz <= 52)
78 crtime -= tz * 15 * 60;