/* $NetBSD: msdosfs_conv.c,v 1.6.2.1 1994/08/30 02:27:57 cgd Exp $ */ /* * Written by Paul Popelka (paulp@uts.amdahl.com) * * You can do anything you want with this software, just don't say you wrote * it, and don't remove this notice. * * This software is provided "as is". * * The author supplies this software to be publicly redistributed on the * understanding that the author is not responsible for the correct * functioning of this software in any circumstances and is not liable for * any damages caused by this software. * * October 1992 */ /* * System include files. */ #include #include #include /* defines tz */ /* * MSDOSFS include files. */ #include /* * Days in each month in a regular year. */ u_short regyear[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; /* * Days in each month in a leap year. */ u_short leapyear[] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; /* * Variables used to remember parts of the last time conversion. Maybe we * can avoid a full conversion. */ u_long lasttime; u_long lastday; u_short lastddate; u_short lastdtime; /* * Convert the unix version of time to dos's idea of time to be used in * file timestamps. The passed in unix time is assumed to be in GMT. */ void unix2dostime(tsp, ddp, dtp) struct timespec *tsp; u_short *ddp; u_short *dtp; { u_long t; u_long days; u_long inc; u_long year; u_long month; u_short *months; /* * If the time from the last conversion is the same as now, then * skip the computations and use the saved result. */ t = tsp->ts_sec - (tz.tz_minuteswest * 60) /* +- daylight savings time correction */ ; if (lasttime != t) { lasttime = t; lastdtime = (((t % 60) >> 1) << DT_2SECONDS_SHIFT) + (((t / 60) % 60) << DT_MINUTES_SHIFT) + (((t / 3600) % 24) << DT_HOURS_SHIFT); /* * If the number of days since 1970 is the same as the last * time we did the computation then skip all this leap year * and month stuff. */ days = t / (24 * 60 * 60); if (days != lastday) { lastday = days; for (year = 1970;; year++) { inc = year & 0x03 ? 365 : 366; if (days < inc) break; days -= inc; } months = year & 0x03 ? regyear : leapyear; for (month = 0; month < 12; month++) { if (days < months[month]) break; days -= months[month]; } lastddate = ((days + 1) << DD_DAY_SHIFT) + ((month + 1) << DD_MONTH_SHIFT); /* * Remember dos's idea of time is relative to 1980. * unix's is relative to 1970. If somehow we get a * time before 1980 then don't give totally crazy * results. */ if (year > 1980) lastddate += (year - 1980) << DD_YEAR_SHIFT; } } *dtp = lastdtime; *ddp = lastddate; } /* * The number of seconds between Jan 1, 1970 and Jan 1, 1980. In that * interval there were 8 regular years and 2 leap years. */ #define SECONDSTO1980 (((8 * 365) + (2 * 366)) * (24 * 60 * 60)) u_short lastdosdate; u_long lastseconds; /* * Convert from dos' idea of time to unix'. This will probably only be * called from the stat(), and fstat() system calls and so probably need * not be too efficient. */ void dos2unixtime(dd, dt, tsp) u_short dd; u_short dt; struct timespec *tsp; { u_long seconds; u_long m, month; u_long y, year; u_long days; u_short *months; seconds = ((dt & DT_2SECONDS_MASK) >> DT_2SECONDS_SHIFT) + ((dt & DT_MINUTES_MASK) >> DT_MINUTES_SHIFT) * 60 + ((dt & DT_HOURS_MASK) >> DT_HOURS_SHIFT) * 3600; /* * If the year, month, and day from the last conversion are the * same then use the saved value. */ if (lastdosdate != dd) { lastdosdate = dd; days = 0; year = (dd & DD_YEAR_MASK) >> DD_YEAR_SHIFT; for (y = 0; y < year; y++) { days += y & 0x03 ? 365 : 366; } months = year & 0x03 ? regyear : leapyear; /* * Prevent going from 0 to 0xffffffff in the following * loop. */ month = (dd & DD_MONTH_MASK) >> DD_MONTH_SHIFT; if (month == 0) { printf("dos2unixtime(): month value out of range (%d)\n", month); month = 1; } for (m = 0; m < month - 1; m++) { days += months[m]; } days += ((dd & DD_DAY_MASK) >> DD_DAY_SHIFT) - 1; lastseconds = (days * 24 * 60 * 60) + SECONDSTO1980; } tsp->ts_sec = seconds + lastseconds + (tz.tz_minuteswest * 60) /* -+ daylight savings time correction */ ; tsp->ts_nsec = 0; } /* * Cheezy macros to do case detection and conversion for the ascii * character set. DOESN'T work for ebcdic. */ #define isupper(c) (c >= 'A' && c <= 'Z') #define islower(c) (c >= 'a' && c <= 'z') #define toupper(c) (c & ~' ') #define tolower(c) (c | ' ') /* * DOS filenames are made of 2 parts, the name part and the extension part. * The name part is 8 characters long and the extension part is 3 * characters long. They may contain trailing blanks if the name or * extension are not long enough to fill their respective fields. */ /* * Convert a DOS filename to a unix filename. And, return the number of * characters in the resulting unix filename excluding the terminating * null. */ int dos2unixfn(dn, un) u_char dn[11]; u_char *un; { int i; int ni; int ei; int thislong = 0; u_char c; u_char *origun = un; /* * Find the last character in the name portion of the dos filename. */ for (ni = 7; ni >= 0; ni--) if (dn[ni] != ' ') break; /* * Find the last character in the extension portion of the * filename. */ for (ei = 10; ei >= 8; ei--) if (dn[ei] != ' ') break; /* * Copy the name portion into the unix filename string. NOTE: DOS * filenames are usually kept in upper case. To make it more unixy * we convert all DOS filenames to lower case. Some may like this, * some may not. */ for (i = 0; i <= ni; i++) { c = dn[i]; *un++ = isupper(c) ? tolower(c) : c; thislong++; } /* * Now, if there is an extension then put in a period and copy in * the extension. */ if (ei >= 8) { *un++ = '.'; thislong++; for (i = 8; i <= ei; i++) { c = dn[i]; *un++ = isupper(c) ? tolower(c) : c; thislong++; } } *un++ = 0; /* * If first char of the filename is SLOT_E5 (0x05), then the real * first char of the filename should be 0xe5. But, they couldn't * just have a 0xe5 mean 0xe5 because that is used to mean a freed * directory slot. Another dos quirk. */ if (*origun == SLOT_E5) *origun = 0xe5; return thislong; } /* * Convert a unix filename to a DOS filename. This function does not ensure * that valid characters for a dos filename are supplied. */ void unix2dosfn(un, dn, unlen) u_char *un; u_char dn[11]; int unlen; { int i; u_char c; /* * Fill the dos filename string with blanks. These are DOS's pad * characters. */ for (i = 0; i <= 10; i++) dn[i] = ' '; /* * The filenames "." and ".." are handled specially, since they * don't follow dos filename rules. */ if (un[0] == '.' && unlen == 1) { dn[0] = '.'; return; } if (un[0] == '.' && un[1] == '.' && unlen == 2) { dn[0] = '.'; dn[1] = '.'; return; } /* * Copy the unix filename into the dos filename string upto the end * of string, a '.', or 8 characters. Whichever happens first stops * us. This forms the name portion of the dos filename. Fold to * upper case. */ for (i = 0; i <= 7 && unlen && (c = *un) && c != '.'; i++) { dn[i] = islower(c) ? toupper(c) : c; un++; unlen--; } /* * If the first char of the filename is 0xe5, then translate it to * 0x05. This is because 0xe5 is the marker for a deleted * directory slot. I guess this means you can't have filenames * that start with 0x05. I suppose we should check for this and * doing something about it. */ if (dn[0] == SLOT_DELETED) dn[0] = SLOT_E5; /* * Strip any further characters up to a '.' or the end of the * string. */ while (unlen && (c = *un)) { un++; unlen--; /* Make sure we've skipped over the dot before stopping. */ if (c == '.') break; } /* * Copy in the extension part of the name, if any. Force to upper * case. Note that the extension is allowed to contain '.'s. * Filenames in this form are probably inaccessable under dos. */ for (i = 8; i <= 10 && unlen && (c = *un); i++) { dn[i] = islower(c) ? toupper(c) : c; un++; unlen--; } } /* * Get rid of these macros before someone discovers we are using such * hideous things. */ #undef isupper #undef islower #undef toupper #undef tolower