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