xref: /netbsd-src/sys/fs/msdosfs/msdosfs_conv.c (revision 001c68bd94f75ce9270b69227c4199fbf34ee396)
1 /*	$NetBSD: msdosfs_conv.c,v 1.1 2002/12/26 12:31:34 jdolecek Exp $	*/
2 
3 /*-
4  * Copyright (C) 1995, 1997 Wolfgang Solfrank.
5  * Copyright (C) 1995, 1997 TooLs GmbH.
6  * All rights reserved.
7  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by TooLs GmbH.
20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 /*
35  * Written by Paul Popelka (paulp@uts.amdahl.com)
36  *
37  * You can do anything you want with this software, just don't say you wrote
38  * it, and don't remove this notice.
39  *
40  * This software is provided "as is".
41  *
42  * The author supplies this software to be publicly redistributed on the
43  * understanding that the author is not responsible for the correct
44  * functioning of this software in any circumstances and is not liable for
45  * any damages caused by this software.
46  *
47  * October 1992
48  */
49 
50 #include <sys/cdefs.h>
51 __KERNEL_RCSID(0, "$NetBSD: msdosfs_conv.c,v 1.1 2002/12/26 12:31:34 jdolecek Exp $");
52 
53 /*
54  * System include files.
55  */
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/time.h>
59 #include <sys/kernel.h>
60 #include <sys/dirent.h>
61 #include <sys/vnode.h>
62 
63 /*
64  * MSDOSFS include files.
65  */
66 #include <fs/msdosfs/direntry.h>
67 #include <fs/msdosfs/denode.h>
68 
69 /*
70  * Days in each month in a regular year.
71  */
72 u_short const regyear[] = {
73 	31, 28, 31, 30, 31, 30,
74 	31, 31, 30, 31, 30, 31
75 };
76 
77 /*
78  * Days in each month in a leap year.
79  */
80 u_short const leapyear[] = {
81 	31, 29, 31, 30, 31, 30,
82 	31, 31, 30, 31, 30, 31
83 };
84 
85 /*
86  * Variables used to remember parts of the last time conversion.  Maybe we
87  * can avoid a full conversion.
88  */
89 u_long lasttime;
90 u_long lastday;
91 u_short lastddate;
92 u_short lastdtime;
93 
94 /*
95  * Convert the unix version of time to dos's idea of time to be used in
96  * file timestamps. The passed in unix time is assumed to be in GMT.
97  */
98 void
99 unix2dostime(tsp, ddp, dtp, dhp)
100 	struct timespec *tsp;
101 	u_int16_t *ddp;
102 	u_int16_t *dtp;
103 	u_int8_t *dhp;
104 {
105 	u_long t;
106 	u_long days;
107 	u_long inc;
108 	u_long year;
109 	u_long month;
110 	const u_short *months;
111 
112 	/*
113 	 * If the time from the last conversion is the same as now, then
114 	 * skip the computations and use the saved result.
115 	 */
116 	t = tsp->tv_sec - (rtc_offset * 60)
117 	     /* +- daylight savings time correction */ ;
118 	t &= ~1;
119 	if (lasttime != t) {
120 		lasttime = t;
121 		lastdtime = (((t / 2) % 30) << DT_2SECONDS_SHIFT)
122 		    + (((t / 60) % 60) << DT_MINUTES_SHIFT)
123 		    + (((t / 3600) % 24) << DT_HOURS_SHIFT);
124 
125 		/*
126 		 * If the number of days since 1970 is the same as the last
127 		 * time we did the computation then skip all this leap year
128 		 * and month stuff.
129 		 */
130 		days = t / (24 * 60 * 60);
131 		if (days != lastday) {
132 			lastday = days;
133 			for (year = 1970;; year++) {
134 				inc = year & 0x03 ? 365 : 366;
135 				if (days < inc)
136 					break;
137 				days -= inc;
138 			}
139 			months = year & 0x03 ? regyear : leapyear;
140 			for (month = 0; month < 12; month++) {
141 				if (days < months[month])
142 					break;
143 				days -= months[month];
144 			}
145 			lastddate = ((days + 1) << DD_DAY_SHIFT)
146 			    + ((month + 1) << DD_MONTH_SHIFT);
147 			/*
148 			 * Remember dos's idea of time is relative to 1980.
149 			 * unix's is relative to 1970.  If somehow we get a
150 			 * time before 1980 then don't give totally crazy
151 			 * results.
152 			 */
153 			if (year > 1980)
154 				lastddate += (year - 1980) << DD_YEAR_SHIFT;
155 		}
156 	}
157 	if (dtp)
158 		*dtp = lastdtime;
159 	if (dhp)
160 		*dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;
161 
162 	*ddp = lastddate;
163 }
164 
165 /*
166  * The number of seconds between Jan 1, 1970 and Jan 1, 1980. In that
167  * interval there were 8 regular years and 2 leap years.
168  */
169 #define	SECONDSTO1980	(((8 * 365) + (2 * 366)) * (24 * 60 * 60))
170 
171 u_short lastdosdate;
172 u_long lastseconds;
173 
174 /*
175  * Convert from dos' idea of time to unix'. This will probably only be
176  * called from the stat(), and fstat() system calls and so probably need
177  * not be too efficient.
178  */
179 void
180 dos2unixtime(dd, dt, dh, tsp)
181 	u_int dd;
182 	u_int dt;
183 	u_int dh;
184 	struct timespec *tsp;
185 {
186 	u_long seconds;
187 	u_long m, month;
188 	u_long y, year;
189 	u_long days;
190 	const u_short *months;
191 
192 	if (dd == 0) {
193 		/*
194 		 * Uninitialized field, return the epoch.
195 		 */
196 		tsp->tv_sec = 0;
197 		tsp->tv_nsec = 0;
198 		return;
199 	}
200 	seconds = ((dt & DT_2SECONDS_MASK) >> DT_2SECONDS_SHIFT) * 2
201 	    + ((dt & DT_MINUTES_MASK) >> DT_MINUTES_SHIFT) * 60
202 	    + ((dt & DT_HOURS_MASK) >> DT_HOURS_SHIFT) * 3600
203 	    + dh / 100;
204 	/*
205 	 * If the year, month, and day from the last conversion are the
206 	 * same then use the saved value.
207 	 */
208 	if (lastdosdate != dd) {
209 		lastdosdate = dd;
210 		days = 0;
211 		year = (dd & DD_YEAR_MASK) >> DD_YEAR_SHIFT;
212 		for (y = 0; y < year; y++)
213 			days += y & 0x03 ? 365 : 366;
214 		months = year & 0x03 ? regyear : leapyear;
215 		/*
216 		 * Prevent going from 0 to 0xffffffff in the following
217 		 * loop.
218 		 */
219 		month = (dd & DD_MONTH_MASK) >> DD_MONTH_SHIFT;
220 		if (month == 0) {
221 			printf("dos2unixtime(): month value out of range (%ld)\n",
222 			    month);
223 			month = 1;
224 		}
225 		for (m = 0; m < month - 1; m++)
226 			days += months[m];
227 		days += ((dd & DD_DAY_MASK) >> DD_DAY_SHIFT) - 1;
228 		lastseconds = (days * 24 * 60 * 60) + SECONDSTO1980;
229 	}
230 	tsp->tv_sec = seconds + lastseconds + (rtc_offset * 60)
231 	     /* -+ daylight savings time correction */ ;
232 	tsp->tv_nsec = (dh % 100) * 10000000;
233 }
234 
235 static const u_char
236 unix2dos[256] = {
237 	0,    0,    0,    0,    0,    0,    0,    0,	/* 00-07 */
238 	0,    0,    0,    0,    0,    0,    0,    0,	/* 08-0f */
239 	0,    0,    0,    0,    0,    0,    0,    0,	/* 10-17 */
240 	0,    0,    0,    0,    0,    0,    0,    0,	/* 18-1f */
241 	0,    '!',  0,    '#',  '$',  '%',  '&',  '\'',	/* 20-27 */
242 	'(',  ')',  0,    '+',  0,    '-',  0,    0,	/* 28-2f */
243 	'0',  '1',  '2',  '3',  '4',  '5',  '6',  '7',	/* 30-37 */
244 	'8',  '9',  0,    0,    0,    0,    0,    0,	/* 38-3f */
245 	'@',  'A',  'B',  'C',  'D',  'E',  'F',  'G',	/* 40-47 */
246 	'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',	/* 48-4f */
247 	'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',	/* 50-57 */
248 	'X',  'Y',  'Z',  0,    0,    0,    '^',  '_',	/* 58-5f */
249 	'`',  'A',  'B',  'C',  'D',  'E',  'F',  'G',	/* 60-67 */
250 	'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',	/* 68-6f */
251 	'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',	/* 70-77 */
252 	'X',  'Y',  'Z',  '{',  0,    '}',  '~',  0,	/* 78-7f */
253 	0,    0,    0,    0,    0,    0,    0,    0,	/* 80-87 */
254 	0,    0,    0,    0,    0,    0,    0,    0,	/* 88-8f */
255 	0,    0,    0,    0,    0,    0,    0,    0,	/* 90-97 */
256 	0,    0,    0,    0,    0,    0,    0,    0,	/* 98-9f */
257 	0,    0xad, 0xbd, 0x9c, 0xcf, 0xbe, 0xdd, 0xf5,	/* a0-a7 */
258 	0xf9, 0xb8, 0xa6, 0xae, 0xaa, 0xf0, 0xa9, 0xee,	/* a8-af */
259 	0xf8, 0xf1, 0xfd, 0xfc, 0xef, 0xe6, 0xf4, 0xfa,	/* b0-b7 */
260 	0xf7, 0xfb, 0xa7, 0xaf, 0xac, 0xab, 0xf3, 0xa8,	/* b8-bf */
261 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* c0-c7 */
262 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* c8-cf */
263 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0x9e,	/* d0-d7 */
264 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0xe1,	/* d8-df */
265 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* e0-e7 */
266 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* e8-ef */
267 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0xf6,	/* f0-f7 */
268 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0x98,	/* f8-ff */
269 };
270 
271 static const u_char
272 dos2unix[256] = {
273 	 '?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',	/* 00-07 */
274 	 '?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',	/* 08-0f */
275 	 '?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',	/* 10-17 */
276 	 '?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',	/* 18-1f */
277 	 ' ',  '!',  '"',  '#',  '$',  '%',  '&', '\'',	/* 20-27 */
278 	 '(',  ')',  '*',  '+',  ',',  '-',  '.',  '/',	/* 28-2f */
279 	 '0',  '1',  '2',  '3',  '4',  '5',  '6',  '7',	/* 30-37 */
280 	 '8',  '9',  ':',  ';',  '<',  '=',  '>',  '?',	/* 38-3f */
281 	 '@',  'A',  'B',  'C',  'D',  'E',  'F',  'G',	/* 40-47 */
282 	 'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',	/* 48-4f */
283 	 'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',	/* 50-57 */
284 	 'X',  'Y',  'Z',  '[', '\\',  ']',  '^',  '_',	/* 58-5f */
285 	 '`',  'a',  'b',  'c',  'd',  'e',  'f',  'g',	/* 60-67 */
286 	 'h',  'i',  'j',  'k',  'l',  'm',  'n',  'o',	/* 68-6f */
287 	 'p',  'q',  'r',  's',  't',  'u',  'v',  'w',	/* 70-77 */
288 	 'x',  'y',  'z',  '{',  '|',  '}',  '~', 0x7f,	/* 78-7f */
289 	0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7,	/* 80-87 */
290 	0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,	/* 88-8f */
291 	0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9,	/* 90-97 */
292 	0xff, 0xd6, 0xdc, 0xf8, 0xa3, 0xd8, 0xd7,  '?',	/* 98-9f */
293 	0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba,	/* a0-a7 */
294 	0xbf, 0xae, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,	/* a8-af */
295 	 '?',  '?',  '?',  '?',  '?', 0xc1, 0xc2, 0xc0,	/* b0-b7 */
296 	0xa9,  '?',  '?',  '?',  '?', 0xa2, 0xa5,  '?',	/* b8-bf */
297 	 '?',  '?',  '?',  '?',  '?',  '?', 0xe3, 0xc3,	/* c0-c7 */
298 	 '?',  '?',  '?',  '?',  '?',  '?',  '?', 0xa4,	/* c8-cf */
299 	0xf0, 0xd0, 0xca, 0xcb, 0xc8,  '?', 0xcd, 0xce,	/* d0-d7 */
300 	0xcf,  '?',  '?',  '?',  '?', 0xa6, 0xcc,  '?',	/* d8-df */
301 	0xd3, 0xdf, 0xd4, 0xd2, 0xf5, 0xd5, 0xb5, 0xfe,	/* e0-e7 */
302 	0xde, 0xda, 0xdb, 0xd9, 0xfd, 0xdd, 0xaf, 0x3f,	/* e8-ef */
303 	0xad, 0xb1,  '?', 0xbe, 0xb6, 0xa7, 0xf7, 0xb8,	/* f0-f7 */
304 	0xb0, 0xa8, 0xb7, 0xb9, 0xb3, 0xb2,  '?',  '?',	/* f8-ff */
305 };
306 
307 static const u_char
308 u2l[256] = {
309 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
310 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
311 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
312 	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
313 	 ' ',  '!',  '"',  '#',  '$',  '%',  '&', '\'', /* 20-27 */
314 	 '(',  ')',  '*',  '+',  ',',  '-',  '.',  '/', /* 28-2f */
315 	 '0',  '1',  '2',  '3',  '4',  '5',  '6',  '7', /* 30-37 */
316 	 '8',  '9',  ':',  ';',  '<',  '=',  '>',  '?', /* 38-3f */
317 	 '@',  'a',  'b',  'c',  'd',  'e',  'f',  'g', /* 40-47 */
318 	 'h',  'i',  'j',  'k',  'l',  'm',  'n',  'o', /* 48-4f */
319 	 'p',  'q',  'r',  's',  't',  'u',  'v',  'w', /* 50-57 */
320 	 'x',  'y',  'z',  '[', '\\',  ']',  '^',  '_', /* 58-5f */
321 	 '`',  'a',  'b',  'c',  'd',  'e',  'f',  'g', /* 60-67 */
322 	 'h',  'i',  'j',  'k',  'l',  'm',  'n',  'o', /* 68-6f */
323 	 'p',  'q',  'r',  's',  't',  'u',  'v',  'w', /* 70-77 */
324 	 'x',  'y',  'z',  '{',  '|',  '}',  '~', 0x7f, /* 78-7f */
325 	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
326 	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
327 	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
328 	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
329 	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
330 	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
331 	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
332 	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
333 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
334 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
335 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
336 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
337 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
338 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
339 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
340 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
341 };
342 
343 /*
344  * DOS filenames are made of 2 parts, the name part and the extension part.
345  * The name part is 8 characters long and the extension part is 3
346  * characters long.  They may contain trailing blanks if the name or
347  * extension are not long enough to fill their respective fields.
348  */
349 
350 /*
351  * Convert a DOS filename to a unix filename. And, return the number of
352  * characters in the resulting unix filename excluding the terminating
353  * null.
354  */
355 int
356 dos2unixfn(dn, un, lower)
357 	u_char dn[11];
358 	u_char *un;
359 	int lower;
360 {
361 	int i, j;
362 	int thislong = 1;
363 	u_char c;
364 
365 	/*
366 	 * If first char of the filename is SLOT_E5 (0x05), then the real
367 	 * first char of the filename should be 0xe5. But, they couldn't
368 	 * just have a 0xe5 mean 0xe5 because that is used to mean a freed
369 	 * directory slot. Another dos quirk.
370 	 */
371 	if (*dn == SLOT_E5)
372 		c = dos2unix[0xe5];
373 	else
374 		c = dos2unix[*dn];
375 	*un++ = lower ? u2l[c] : c;
376 
377 	/*
378 	 * Copy the rest into the unix filename string, ignoring
379 	 * trailing blanks.
380 	 */
381 
382 	for (j=7; (j >= 0) && (dn[j] == ' '); j--)
383 		;
384 
385 	for (i = 1; i <= j; i++) {
386 		c = dos2unix[dn[i]];
387 		*un++ = lower ? u2l[c] : c;
388 		thislong++;
389 	}
390 	dn += 8;
391 
392 	/*
393 	 * Now, if there is an extension then put in a period and copy in
394 	 * the extension.
395 	 */
396 	if (*dn != ' ') {
397 		*un++ = '.';
398 		thislong++;
399 		for (i = 0; i < 3 && *dn != ' '; i++) {
400 			c = dos2unix[*dn++];
401 			*un++ = lower ? u2l[c] : c;
402 			thislong++;
403 		}
404 	}
405 	*un++ = 0;
406 
407 	return (thislong);
408 }
409 
410 /*
411  * Convert a unix filename to a DOS filename according to Win95 rules.
412  * If applicable and gen is not 0, it is inserted into the converted
413  * filename as a generation number.
414  * Returns
415  *	0 if name couldn't be converted
416  *	1 if the converted name is the same as the original
417  *	  (no long filename entry necessary for Win95)
418  *	2 if conversion was successful
419  *	3 if conversion was successful and generation number was inserted
420  */
421 int
422 unix2dosfn(un, dn, unlen, gen)
423 	const u_char *un;
424 	u_char dn[12];
425 	int unlen;
426 	u_int gen;
427 {
428 	int i, j, l;
429 	int conv = 1;
430 	const u_char *cp, *dp, *dp1;
431 	u_char gentext[6], *wcp;
432 	int shortlen;
433 
434 	/*
435 	 * Fill the dos filename string with blanks. These are DOS's pad
436 	 * characters.
437 	 */
438 	for (i = 0; i < 11; i++)
439 		dn[i] = ' ';
440 	dn[11] = 0;
441 
442 	/*
443 	 * The filenames "." and ".." are handled specially, since they
444 	 * don't follow dos filename rules.
445 	 */
446 	if (un[0] == '.' && unlen == 1) {
447 		dn[0] = '.';
448 		return gen <= 1;
449 	}
450 	if (un[0] == '.' && un[1] == '.' && unlen == 2) {
451 		dn[0] = '.';
452 		dn[1] = '.';
453 		return gen <= 1;
454 	}
455 
456 	/*
457 	 * Filenames with only blanks and dots are not allowed!
458 	 */
459 	for (cp = un, i = unlen; --i >= 0; cp++)
460 		if (*cp != ' ' && *cp != '.')
461 			break;
462 	if (i < 0)
463 		return 0;
464 
465 	/*
466 	 * Now find the extension
467 	 * Note: dot as first char doesn't start extension
468 	 *	 and trailing dots and blanks are ignored
469 	 */
470 	dp = dp1 = 0;
471 	for (cp = un + 1, i = unlen - 1; --i >= 0;) {
472 		switch (*cp++) {
473 		case '.':
474 			if (!dp1)
475 				dp1 = cp;
476 			break;
477 		case ' ':
478 			break;
479 		default:
480 			if (dp1)
481 				dp = dp1;
482 			dp1 = 0;
483 			break;
484 		}
485 	}
486 
487 	/*
488 	 * Now convert it
489 	 */
490 	if (dp) {
491 		if (dp1)
492 			l = dp1 - dp;
493 		else
494 			l = unlen - (dp - un);
495 		for (i = 0, j = 8; i < l && j < 11; i++, j++) {
496 			if (dp[i] != (dn[j] = unix2dos[dp[i]])
497 			    && conv != 3)
498 				conv = 2;
499 			if (!dn[j]) {
500 				conv = 3;
501 				dn[j--] = ' ';
502 			}
503 		}
504 		if (i < l)
505 			conv = 3;
506 		dp--;
507 	} else {
508 		for (dp = cp; *--dp == ' ' || *dp == '.';);
509 		dp++;
510 	}
511 
512 	shortlen = (dp - un) <= 8;
513 
514 	/*
515 	 * Now convert the rest of the name
516 	 */
517 	for (i = j = 0; un < dp && j < 8; i++, j++, un++) {
518 		if ((*un == ' ') && shortlen)
519 			dn[j] = ' ';
520 		else
521 			dn[j] = unix2dos[*un];
522 		if ((*un != dn[j])
523 		    && conv != 3)
524 			conv = 2;
525 		if (!dn[j]) {
526 			conv = 3;
527 			dn[j--] = ' ';
528 		}
529 	}
530 	if (un < dp)
531 		conv = 3;
532 	/*
533 	 * If we didn't have any chars in filename,
534 	 * generate a default
535 	 */
536 	if (!j)
537 		dn[0] = '_';
538 
539 	/*
540 	 * The first character cannot be E5,
541 	 * because that means a deleted entry
542 	 */
543 	if (dn[0] == 0xe5)
544 		dn[0] = SLOT_E5;
545 
546 	/*
547 	 * If there wasn't any char dropped,
548 	 * there is no place for generation numbers
549 	 */
550 	if (conv != 3) {
551 		if (gen > 1)
552 			return 0;
553 		return conv;
554 	}
555 
556 	/*
557 	 * Now insert the generation number into the filename part
558 	 */
559 	for (wcp = gentext + sizeof(gentext); wcp > gentext && gen; gen /= 10)
560 		*--wcp = gen % 10 + '0';
561 	if (gen)
562 		return 0;
563 	for (i = 8; dn[--i] == ' ';);
564 	i++;
565 	if (gentext + sizeof(gentext) - wcp + 1 > 8 - i)
566 		i = 8 - (gentext + sizeof(gentext) - wcp + 1);
567 	dn[i++] = '~';
568 	while (wcp < gentext + sizeof(gentext))
569 		dn[i++] = *wcp++;
570 	return 3;
571 }
572 
573 /*
574  * Create a Win95 long name directory entry
575  * Note: assumes that the filename is valid,
576  *	 i.e. doesn't consist solely of blanks and dots
577  */
578 int
579 unix2winfn(un, unlen, wep, cnt, chksum)
580 	const u_char *un;
581 	int unlen;
582 	struct winentry *wep;
583 	int cnt;
584 	int chksum;
585 {
586 	const u_int8_t *cp;
587 	u_int8_t *wcp;
588 	int i;
589 
590 	/*
591 	 * Drop trailing blanks and dots
592 	 */
593 	for (cp = un + unlen; *--cp == ' ' || *cp == '.'; unlen--);
594 
595 	un += (cnt - 1) * WIN_CHARS;
596 	unlen -= (cnt - 1) * WIN_CHARS;
597 
598 	/*
599 	 * Initialize winentry to some useful default
600 	 */
601 	for (wcp = (u_int8_t *)wep, i = sizeof(*wep); --i >= 0; *wcp++ = 0xff);
602 	wep->weCnt = cnt;
603 	wep->weAttributes = ATTR_WIN95;
604 	wep->weReserved1 = 0;
605 	wep->weChksum = chksum;
606 	wep->weReserved2 = 0;
607 
608 	/*
609 	 * Now convert the filename parts
610 	 */
611 	for (wcp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
612 		if (--unlen < 0)
613 			goto done;
614 		*wcp++ = *un++;
615 		*wcp++ = 0;
616 	}
617 	for (wcp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
618 		if (--unlen < 0)
619 			goto done;
620 		*wcp++ = *un++;
621 		*wcp++ = 0;
622 	}
623 	for (wcp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
624 		if (--unlen < 0)
625 			goto done;
626 		*wcp++ = *un++;
627 		*wcp++ = 0;
628 	}
629 	if (!unlen)
630 		wep->weCnt |= WIN_LAST;
631 	return unlen;
632 
633 done:
634 	*wcp++ = 0;
635 	*wcp++ = 0;
636 	wep->weCnt |= WIN_LAST;
637 	return 0;
638 }
639 
640 /*
641  * Compare our filename to the one in the Win95 entry
642  * Returns the checksum or -1 if no match
643  */
644 int
645 winChkName(un, unlen, wep, chksum)
646 	const u_char *un;
647 	int unlen;
648 	struct winentry *wep;
649 	int chksum;
650 {
651 	u_int8_t *cp;
652 	int i;
653 
654 	/*
655 	 * First compare checksums
656 	 */
657 	if (wep->weCnt&WIN_LAST)
658 		chksum = wep->weChksum;
659 	else if (chksum != wep->weChksum)
660 		chksum = -1;
661 	if (chksum == -1)
662 		return -1;
663 
664 	/*
665 	 * Offset of this entry
666 	 */
667 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
668 	un += i;
669 	if ((unlen -= i) < 0)
670 		return -1;
671 
672 	/*
673 	 * Ignore redundant winentries (those with only \0\0 on start in them).
674 	 * An appearance of such entry is a bug; unknown if in NetBSD msdosfs
675 	 * or MS Windows.
676 	 */
677 	if (unlen == 0) {
678 		if (wep->wePart1[0] == '\0' && wep->wePart1[1] == '\0')
679 			return chksum;
680 		else
681 			return -1;
682 	}
683 
684 	if ((wep->weCnt&WIN_LAST) && unlen > WIN_CHARS)
685 		return -1;
686 
687 	/*
688 	 * Compare the name parts
689 	 */
690 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
691 		if (--unlen < 0) {
692 			if (!*cp++ && !*cp)
693 				return chksum;
694 			return -1;
695 		}
696 		if (u2l[*cp++] != u2l[*un++] || *cp++)
697 			return -1;
698 	}
699 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
700 		if (--unlen < 0) {
701 			if (!*cp++ && !*cp)
702 				return chksum;
703 			return -1;
704 		}
705 		if (u2l[*cp++] != u2l[*un++] || *cp++)
706 			return -1;
707 	}
708 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
709 		if (--unlen < 0) {
710 			if (!*cp++ && !*cp)
711 				return chksum;
712 			return -1;
713 		}
714 		if (u2l[*cp++] != u2l[*un++] || *cp++)
715 			return -1;
716 	}
717 	return chksum;
718 }
719 
720 /*
721  * Convert Win95 filename to dirbuf.
722  * Returns the checksum or -1 if impossible
723  */
724 int
725 win2unixfn(wep, dp, chksum)
726 	struct winentry *wep;
727 	struct dirent *dp;
728 	int chksum;
729 {
730 	u_int8_t *cp;
731 	u_int8_t *np, *ep = dp->d_name + WIN_MAXLEN;
732 	int i;
733 
734 	if ((wep->weCnt&WIN_CNT) > howmany(WIN_MAXLEN, WIN_CHARS)
735 	    || !(wep->weCnt&WIN_CNT))
736 		return -1;
737 
738 	/*
739 	 * First compare checksums
740 	 */
741 	if (wep->weCnt&WIN_LAST) {
742 		chksum = wep->weChksum;
743 		/*
744 		 * This works even though d_namlen is one byte!
745 		 */
746 		dp->d_namlen = (wep->weCnt&WIN_CNT) * WIN_CHARS;
747 	} else if (chksum != wep->weChksum)
748 		chksum = -1;
749 	if (chksum == -1)
750 		return -1;
751 
752 	/*
753 	 * Offset of this entry
754 	 */
755 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
756 	np = (u_int8_t *)dp->d_name + i;
757 
758 	/*
759 	 * Convert the name parts
760 	 */
761 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
762 		switch (*np++ = *cp++) {
763 		case 0:
764 			dp->d_namlen -= sizeof(wep->wePart2)/2
765 			    + sizeof(wep->wePart3)/2 + i + 1;
766 			return chksum;
767 		case '/':
768 			np[-1] = 0;
769 			return -1;
770 		}
771 		/*
772 		 * The size comparison should result in the compiler
773 		 * optimizing the whole if away
774 		 */
775 		if (WIN_MAXLEN % WIN_CHARS < sizeof(wep->wePart1) / 2
776 		    && np > ep) {
777 			np[-1] = 0;
778 			return -1;
779 		}
780 		if (*cp++)
781 			return -1;
782 	}
783 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
784 		switch (*np++ = *cp++) {
785 		case 0:
786 			dp->d_namlen -= sizeof(wep->wePart3)/2 + i + 1;
787 			return chksum;
788 		case '/':
789 			np[-1] = 0;
790 			return -1;
791 		}
792 		/*
793 		 * The size comparisons should be optimized away
794 		 */
795 		if (WIN_MAXLEN % WIN_CHARS >= sizeof(wep->wePart1) / 2
796 		    && WIN_MAXLEN % WIN_CHARS < (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
797 		    && np > ep) {
798 			np[-1] = 0;
799 			return -1;
800 		}
801 		if (*cp++)
802 			return -1;
803 	}
804 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
805 		switch (*np++ = *cp++) {
806 		case 0:
807 			dp->d_namlen -= i + 1;
808 			return chksum;
809 		case '/':
810 			np[-1] = 0;
811 			return -1;
812 		}
813 		/*
814 		 * See above
815 		 */
816 		if (WIN_MAXLEN % WIN_CHARS >= (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
817 		    && np > ep) {
818 			np[-1] = 0;
819 			return -1;
820 		}
821 		if (*cp++)
822 			return -1;
823 	}
824 	return chksum;
825 }
826 
827 /*
828  * Compute the checksum of a DOS filename for Win95 use
829  */
830 u_int8_t
831 winChksum(name)
832 	u_int8_t *name;
833 {
834 	int i;
835 	u_int8_t s;
836 
837 	for (s = 0, i = 11; --i >= 0; s += *name++)
838 		s = (s << 7)|(s >> 1);
839 	return s;
840 }
841 
842 /*
843  * Determine the number of slots necessary for Win95 names
844  */
845 int
846 winSlotCnt(un, unlen)
847 	const u_char *un;
848 	int unlen;
849 {
850 	for (un += unlen; unlen > 0; unlen--)
851 		if (*--un != ' ' && *un != '.')
852 			break;
853 	if (unlen > WIN_MAXLEN)
854 		return 0;
855 	return howmany(unlen, WIN_CHARS);
856 }
857