From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/isofs/util.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 fs/isofs/util.c (limited to 'fs/isofs/util.c') diff --git a/fs/isofs/util.c b/fs/isofs/util.c new file mode 100644 index 000000000..005a15cfd --- /dev/null +++ b/fs/isofs/util.c @@ -0,0 +1,70 @@ +/* + * linux/fs/isofs/util.c + */ + +#include +#include "isofs.h" + +/* + * We have to convert from a MM/DD/YY format to the Unix ctime format. + * We have to take into account leap years and all of that good stuff. + * Unfortunately, the kernel does not have the information on hand to + * take into account daylight savings time, but it shouldn't matter. + * The time stored should be localtime (with or without DST in effect), + * and the timezone offset should hold the offset required to get back + * to GMT. Thus we should always be correct. + */ + +int iso_date(char * p, int flag) +{ + int year, month, day, hour, minute, second, tz; + int crtime; + + year = p[0]; + month = p[1]; + day = p[2]; + hour = p[3]; + minute = p[4]; + second = p[5]; + if (flag == 0) tz = p[6]; /* High sierra has no time zone */ + else tz = 0; + + if (year < 0) { + crtime = 0; + } else { + crtime = mktime64(year+1900, month, day, hour, minute, second); + + /* sign extend */ + if (tz & 0x80) + tz |= (-1 << 8); + + /* + * The timezone offset is unreliable on some disks, + * so we make a sanity check. In no case is it ever + * more than 13 hours from GMT, which is 52*15min. + * The time is always stored in localtime with the + * timezone offset being what get added to GMT to + * get to localtime. Thus we need to subtract the offset + * to get to true GMT, which is what we store the time + * as internally. On the local system, the user may set + * their timezone any way they wish, of course, so GMT + * gets converted back to localtime on the receiving + * system. + * + * NOTE: mkisofs in versions prior to mkisofs-1.10 had + * the sign wrong on the timezone offset. This has now + * been corrected there too, but if you are getting screwy + * results this may be the explanation. If enough people + * complain, a user configuration option could be added + * to add the timezone offset in with the wrong sign + * for 'compatibility' with older discs, but I cannot see how + * it will matter that much. + * + * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann) + * for pointing out the sign error. + */ + if (-52 <= tz && tz <= 52) + crtime -= tz * 15 * 60; + } + return crtime; +} -- cgit v1.2.3-54-g00ecf