xref: /openbsd/sys/msdosfs/msdosfs_conv.c (revision 7b36286a)
1 /*	$OpenBSD: msdosfs_conv.c,v 1.13 2004/05/14 04:05:05 tedu Exp $	*/
2 /*	$NetBSD: msdosfs_conv.c,v 1.24 1997/10/17 11:23:54 ws Exp $	*/
3 
4 /*-
5  * Copyright (C) 1995, 1997 Wolfgang Solfrank.
6  * Copyright (C) 1995, 1997 TooLs GmbH.
7  * All rights reserved.
8  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 /*
36  * Written by Paul Popelka (paulp@uts.amdahl.com)
37  *
38  * You can do anything you want with this software, just don't say you wrote
39  * it, and don't remove this notice.
40  *
41  * This software is provided "as is".
42  *
43  * The author supplies this software to be publicly redistributed on the
44  * understanding that the author is not responsible for the correct
45  * functioning of this software in any circumstances and is not liable for
46  * any damages caused by this software.
47  *
48  * October 1992
49  */
50 
51 /*
52  * System include files.
53  */
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/time.h>
57 #include <sys/kernel.h>		/* defines tz */
58 #include <sys/dirent.h>
59 #include <sys/vnode.h>
60 
61 /*
62  * MSDOSFS include files.
63  */
64 #include <msdosfs/direntry.h>
65 #include <msdosfs/denode.h>
66 
67 /*
68  * Days in each month in a regular year.
69  */
70 const u_short regyear[] = {
71 	31, 28, 31, 30, 31, 30,
72 	31, 31, 30, 31, 30, 31
73 };
74 
75 /*
76  * Days in each month in a leap year.
77  */
78 const u_short leapyear[] = {
79 	31, 29, 31, 30, 31, 30,
80 	31, 31, 30, 31, 30, 31
81 };
82 
83 /*
84  * Variables used to remember parts of the last time conversion.  Maybe we
85  * can avoid a full conversion.
86  */
87 uint32_t lasttime;
88 uint32_t lastday;
89 u_short lastddate;
90 u_short lastdtime;
91 
92 /*
93  * Convert the unix version of time to dos's idea of time to be used in
94  * file timestamps. The passed in unix time is assumed to be in GMT.
95  */
96 void
97 unix2dostime(tsp, ddp, dtp, dhp)
98 	struct timespec *tsp;
99 	u_int16_t *ddp;
100 	u_int16_t *dtp;
101 	u_int8_t *dhp;
102 {
103 	uint32_t t;
104 	uint32_t days;
105 	uint32_t inc;
106 	uint32_t year;
107 	uint32_t month;
108 	const u_short *months;
109 
110 	/*
111 	 * If the time from the last conversion is the same as now, then
112 	 * skip the computations and use the saved result.
113 	 */
114 	t = tsp->tv_sec - (tz.tz_minuteswest * 60)
115 	     /* +- daylight saving time correction */ ;
116 	t &= ~1;
117 	if (lasttime != t) {
118 		lasttime = t;
119 		lastdtime = (((t / 2) % 30) << DT_2SECONDS_SHIFT)
120 		    + (((t / 60) % 60) << DT_MINUTES_SHIFT)
121 		    + (((t / 3600) % 24) << DT_HOURS_SHIFT);
122 
123 		/*
124 		 * If the number of days since 1970 is the same as the last
125 		 * time we did the computation then skip all this leap year
126 		 * and month stuff.
127 		 */
128 		days = t / (24 * 60 * 60);
129 		if (days != lastday) {
130 			lastday = days;
131 			for (year = 1970;; year++) {
132 				inc = year & 0x03 ? 365 : 366;
133 				if (days < inc)
134 					break;
135 				days -= inc;
136 			}
137 			months = year & 0x03 ? regyear : leapyear;
138 			for (month = 0; month < 12; month++) {
139 				if (days < months[month])
140 					break;
141 				days -= months[month];
142 			}
143 			lastddate = ((days + 1) << DD_DAY_SHIFT)
144 			    + ((month + 1) << DD_MONTH_SHIFT);
145 			/*
146 			 * Remember dos's idea of time is relative to 1980.
147 			 * unix's is relative to 1970.  If somehow we get a
148 			 * time before 1980 then don't give totally crazy
149 			 * results.
150 			 */
151 			if (year > 1980)
152 				lastddate += (year - 1980) << DD_YEAR_SHIFT;
153 		}
154 	}
155 
156 	if (dtp != NULL)
157 		*dtp = lastdtime;
158 	if (dhp != NULL)
159 	        *dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;
160 
161 	*ddp = lastddate;
162 }
163 
164 /*
165  * The number of seconds between Jan 1, 1970 and Jan 1, 1980. In that
166  * interval there were 8 regular years and 2 leap years.
167  */
168 #define	SECONDSTO1980	(((8 * 365) + (2 * 366)) * (24 * 60 * 60))
169 
170 u_short lastdosdate;
171 uint32_t lastseconds;
172 
173 /*
174  * Convert from dos' idea of time to unix'. This will probably only be
175  * called from the stat(), and fstat() system calls and so probably need
176  * not be too efficient.
177  */
178 void
179 dos2unixtime(dd, dt, dh, tsp)
180 	u_int dd;
181 	u_int dt;
182 	u_int dh;
183 	struct timespec *tsp;
184 {
185 	uint32_t seconds;
186 	uint32_t m, month;
187 	uint32_t y, year;
188 	uint32_t days;
189 	const u_short *months;
190 
191 	if (dd == 0) {
192 		/*
193 		 * Uninitialized field, return the epoch.
194 		 */
195 		tsp->tv_sec = 0;
196 		tsp->tv_nsec = 0;
197 		return;
198 	}
199 	seconds = ((dt & DT_2SECONDS_MASK) >> DT_2SECONDS_SHIFT) * 2
200 	    + ((dt & DT_MINUTES_MASK) >> DT_MINUTES_SHIFT) * 60
201 	    + ((dt & DT_HOURS_MASK) >> DT_HOURS_SHIFT) * 3600
202 	    + dh / 100;
203 	/*
204 	 * If the year, month, and day from the last conversion are the
205 	 * same then use the saved value.
206 	 */
207 	if (lastdosdate != dd) {
208 		lastdosdate = dd;
209 		days = 0;
210 		year = (dd & DD_YEAR_MASK) >> DD_YEAR_SHIFT;
211 		for (y = 0; y < year; y++)
212 			days += y & 0x03 ? 365 : 366;
213 		months = year & 0x03 ? regyear : leapyear;
214 		/*
215 		 * Prevent going from 0 to 0xffffffff in the following
216 		 * loop.
217 		 */
218 		month = (dd & DD_MONTH_MASK) >> DD_MONTH_SHIFT;
219 		if (month == 0) {
220 			printf("dos2unixtime(): month value out of range (%ld)\n",
221 			    month);
222 			month = 1;
223 		}
224 		for (m = 0; m < month - 1; m++)
225 			days += months[m];
226 		days += ((dd & DD_DAY_MASK) >> DD_DAY_SHIFT) - 1;
227 		lastseconds = (days * 24 * 60 * 60) + SECONDSTO1980;
228 	}
229 	tsp->tv_sec = seconds + lastseconds + (tz.tz_minuteswest * 60)
230 	     /* -+ daylight saving time correction */ ;
231 	tsp->tv_nsec = (dh % 100) * 10000000;
232 }
233 
234 static const u_char
235 unix2dos[256] = {
236 	0,    0,    0,    0,    0,    0,    0,    0,	/* 00-07 */
237 	0,    0,    0,    0,    0,    0,    0,    0,	/* 08-0f */
238 	0,    0,    0,    0,    0,    0,    0,    0,	/* 10-17 */
239 	0,    0,    0,    0,    0,    0,    0,    0,	/* 18-1f */
240 	0,    0x21, 0,    0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
241 	0x28, 0x29, 0,    0,    0,    0x2d, 0,    0,	/* 28-2f */
242 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
243 	0x38, 0x39, 0,    0,    0,    0,    0,    0,	/* 38-3f */
244 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
245 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
246 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
247 	0x58, 0x59, 0x5a, 0,    0,    0,    0x5e, 0x5f,	/* 58-5f */
248 	0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 60-67 */
249 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 68-6f */
250 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 70-77 */
251 	0x58, 0x59, 0x5a, 0x7b, 0,    0x7d, 0x7e, 0,	/* 78-7f */
252 	0,    0,    0,    0,    0,    0,    0,    0,	/* 80-87 */
253 	0,    0,    0,    0,    0,    0,    0,    0,	/* 88-8f */
254 	0,    0,    0,    0,    0,    0,    0,    0,	/* 90-97 */
255 	0,    0,    0,    0,    0,    0,    0,    0,	/* 98-9f */
256 	0,    0xad, 0xbd, 0x9c, 0xcf, 0xbe, 0xdd, 0xf5,	/* a0-a7 */
257 	0xf9, 0xb8, 0xa6, 0xae, 0xaa, 0xf0, 0xa9, 0xee,	/* a8-af */
258 	0xf8, 0xf1, 0xfd, 0xfc, 0xef, 0xe6, 0xf4, 0xfa,	/* b0-b7 */
259 	0xf7, 0xfb, 0xa7, 0xaf, 0xac, 0xab, 0xf3, 0xa8,	/* b8-bf */
260 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* c0-c7 */
261 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* c8-cf */
262 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0x9e,	/* d0-d7 */
263 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0xe1,	/* d8-df */
264 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* e0-e7 */
265 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* e8-ef */
266 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0xf6,	/* f0-f7 */
267 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0x98,	/* f8-ff */
268 };
269 
270 static const u_char
271 dos2unix[256] = {
272 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 00-07 */
273 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 08-0f */
274 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 10-17 */
275 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 18-1f */
276 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
277 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,	/* 28-2f */
278 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
279 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,	/* 38-3f */
280 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
281 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
282 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
283 	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,	/* 58-5f */
284 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,	/* 60-67 */
285 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,	/* 68-6f */
286 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,	/* 70-77 */
287 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,	/* 78-7f */
288 	0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7,	/* 80-87 */
289 	0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,	/* 88-8f */
290 	0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9,	/* 90-97 */
291 	0xff, 0xd6, 0xdc, 0xf8, 0xa3, 0xd8, 0xd7, 0x3f,	/* 98-9f */
292 	0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba,	/* a0-a7 */
293 	0xbf, 0xae, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,	/* a8-af */
294 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xc1, 0xc2, 0xc0,	/* b0-b7 */
295 	0xa9, 0x3f, 0x3f, 0x3f, 0x3f, 0xa2, 0xa5, 0x3f,	/* b8-bf */
296 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xe3, 0xc3,	/* c0-c7 */
297 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xa4,	/* c8-cf */
298 	0xf0, 0xd0, 0xca, 0xcb, 0xc8, 0x3f, 0xcd, 0xce,	/* d0-d7 */
299 	0xcf, 0x3f, 0x3f, 0x3f, 0x3f, 0xa6, 0xcc, 0x3f,	/* d8-df */
300 	0xd3, 0xdf, 0xd4, 0xd2, 0xf5, 0xd5, 0xb5, 0xfe,	/* e0-e7 */
301 	0xde, 0xda, 0xdb, 0xd9, 0xfd, 0xdd, 0xaf, 0x3f,	/* e8-ef */
302 	0xad, 0xb1, 0x3f, 0xbe, 0xb6, 0xa7, 0xf7, 0xb8,	/* f0-f7 */
303 	0xb0, 0xa8, 0xb7, 0xb9, 0xb3, 0xb2, 0x3f, 0x3f,	/* f8-ff */
304 };
305 
306 static const u_char
307 u2l[256] = {
308 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
309 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
310 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
311 	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
312 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 20-27 */
313 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 28-2f */
314 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 30-37 */
315 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 38-3f */
316 	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 40-47 */
317 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 48-4f */
318 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 50-57 */
319 	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 58-5f */
320 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 60-67 */
321 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 68-6f */
322 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 70-77 */
323 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 78-7f */
324 	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
325 	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
326 	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
327 	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
328 	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
329 	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
330 	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
331 	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
332 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
333 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
334 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
335 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
336 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
337 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
338 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
339 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
340 };
341 
342 /*
343  * DOS filenames are made of 2 parts, the name part and the extension part.
344  * The name part is 8 characters long and the extension part is 3
345  * characters long.  They may contain trailing blanks if the name or
346  * extension are not long enough to fill their respective fields.
347  */
348 
349 /*
350  * Convert a DOS filename to a unix filename. And, return the number of
351  * characters in the resulting unix filename excluding the terminating
352  * null.
353  */
354 int
355 dos2unixfn(dn, un, lower)
356 	u_char dn[11];
357 	u_char *un;
358 	int lower;
359 {
360 	int i;
361 	int thislong = 1;
362 	u_char c;
363 
364 	/*
365 	 * If first char of the filename is SLOT_E5 (0x05), then the real
366 	 * first char of the filename should be 0xe5. But, they couldn't
367 	 * just have a 0xe5 mean 0xe5 because that is used to mean a freed
368 	 * directory slot. Another dos quirk.
369 	 */
370 	if (*dn == SLOT_E5)
371 		c = dos2unix[0xe5];
372 	else
373 		c = dos2unix[*dn];
374 	*un++ = lower ? u2l[c] : c;
375 	dn++;
376 
377 	/*
378 	 * Copy the name portion into the unix filename string.
379 	 */
380 	for (i = 1; i < 8 && *dn != ' '; i++) {
381 		c = dos2unix[*dn++];
382 		*un++ = lower ? u2l[c] : c;
383 		thislong++;
384 	}
385 	dn += 8 - i;
386 
387 	/*
388 	 * Now, if there is an extension then put in a period and copy in
389 	 * the extension.
390 	 */
391 	if (*dn != ' ') {
392 		*un++ = '.';
393 		thislong++;
394 		for (i = 0; i < 3 && *dn != ' '; i++) {
395 			c = dos2unix[*dn++];
396 			*un++ = lower ? u2l[c] : c;
397 			thislong++;
398 		}
399 	}
400 	*un++ = 0;
401 
402 	return (thislong);
403 }
404 
405 /*
406  * Convert a unix filename to a DOS filename according to Win95 rules.
407  * If applicable and gen is not 0, it is inserted into the converted
408  * filename as a generation number.
409  * Returns
410  *	0 if name couldn't be converted
411  *	1 if the converted name is the same as the original
412  *	  (no long filename entry necessary for Win95)
413  *	2 if conversion was successful
414  *	3 if conversion was successful and generation number was inserted
415  */
416 int
417 unix2dosfn(un, dn, unlen, gen)
418 	u_char *un;
419 	u_char dn[12];
420 	int unlen;
421 	u_int gen;
422 {
423 	int i, j, l;
424 	int conv = 1;
425 	u_char *cp, *dp, *dp1;
426 	u_char gentext[6];
427 
428 	/*
429 	 * Fill the dos filename string with blanks. These are DOS's pad
430 	 * characters.
431 	 */
432 	for (i = 0; i < 11; i++)
433 		dn[i] = ' ';
434 	dn[11] = 0;
435 
436 	/*
437 	 * The filenames "." and ".." are handled specially, since they
438 	 * don't follow dos filename rules.
439 	 */
440 	if (un[0] == '.' && unlen == 1) {
441 		dn[0] = '.';
442 		return gen <= 1;
443 	}
444 	if (un[0] == '.' && un[1] == '.' && unlen == 2) {
445 		dn[0] = '.';
446 		dn[1] = '.';
447 		return gen <= 1;
448 	}
449 
450 	/*
451 	 * Filenames with only blanks and dots are not allowed!
452 	 */
453 	for (cp = un, i = unlen; --i >= 0; cp++)
454 		if (*cp != ' ' && *cp != '.')
455 			break;
456 	if (i < 0)
457 		return 0;
458 
459 	/*
460 	 * Now find the extension
461 	 * Note: dot as first char doesn't start extension
462 	 *	 and trailing dots and blanks are ignored
463 	 */
464 	dp = dp1 = 0;
465 	for (cp = un + 1, i = unlen - 1; --i >= 0;) {
466 		switch (*cp++) {
467 		case '.':
468 			if (!dp1)
469 				dp1 = cp;
470 			break;
471 		case ' ':
472 			break;
473 		default:
474 			if (dp1)
475 				dp = dp1;
476 			dp1 = 0;
477 			break;
478 		}
479 	}
480 
481 	/*
482 	 * Now convert it
483 	 */
484 	if (dp) {
485 		if (dp1)
486 			l = dp1 - dp;
487 		else
488 			l = unlen - (dp - un);
489 		for (i = 0, j = 8; i < l && j < 11; i++, j++) {
490 			if (dp[i] != (dn[j] = unix2dos[dp[i]])
491 			    && conv != 3)
492 				conv = 2;
493 			if (!dn[j]) {
494 				conv = 3;
495 				dn[j--] = ' ';
496 			}
497 		}
498 		if (i < l)
499 			conv = 3;
500 		dp--;
501 	} else {
502 		for (dp = cp; *--dp == ' ' || *dp == '.';);
503 		dp++;
504 	}
505 
506 	/*
507 	 * Now convert the rest of the name
508 	 */
509 	for (i = j = 0; un < dp && j < 8; i++, j++, un++) {
510 		if (*un != (dn[j] = unix2dos[*un])
511 		    && conv != 3)
512 			conv = 2;
513 		if (!dn[j]) {
514 			conv = 3;
515 			dn[j--] = ' ';
516 		}
517 	}
518 	if (un < dp)
519 		conv = 3;
520 	/*
521 	 * If we didn't have any chars in filename,
522 	 * generate a default
523 	 */
524 	if (!j)
525 		dn[0] = '_';
526 
527 	/*
528 	 * The first character cannot be E5,
529 	 * because that means a deleted entry
530 	 */
531 	if (dn[0] == 0xe5)
532 		dn[0] = SLOT_E5;
533 
534 	/*
535 	 * If there wasn't any char dropped,
536 	 * there is no place for generation numbers
537 	 */
538 	if (conv != 3) {
539 		if (gen > 1)
540 			return 0;
541 		return conv;
542 	}
543 
544 	/*
545 	 * Now insert the generation number into the filename part
546 	 */
547 	for (cp = gentext + sizeof(gentext); cp > gentext && gen; gen /= 10)
548 		*--cp = gen % 10 + '0';
549 	if (gen)
550 		return 0;
551 	for (i = 8; dn[--i] == ' ';);
552 	if (gentext + sizeof(gentext) - cp + 1 > 8 - i)
553 		i = 8 - (gentext + sizeof(gentext) - cp + 1);
554 	dn[i++] = '~';
555 	while (cp < gentext + sizeof(gentext))
556 		dn[i++] = *cp++;
557 	return 3;
558 }
559 
560 /*
561  * Create a Win95 long name directory entry
562  * Note: assumes that the filename is valid,
563  *	 i.e. doesn't consist solely of blanks and dots
564  */
565 int
566 unix2winfn(un, unlen, wep, cnt, chksum)
567 	u_char *un;
568 	int unlen;
569 	struct winentry *wep;
570 	int cnt;
571 	int chksum;
572 {
573 	u_int8_t *cp;
574 	int i;
575 
576 	/*
577 	 * Drop trailing blanks and dots
578 	 */
579 	for (cp = un + unlen; *--cp == ' ' || *cp == '.'; unlen--);
580 
581 	un += (cnt - 1) * WIN_CHARS;
582 	unlen -= (cnt - 1) * WIN_CHARS;
583 
584 	/*
585 	 * Initialize winentry to some useful default
586 	 */
587 	for (cp = (u_int8_t *)wep, i = sizeof(*wep); --i >= 0; *cp++ = 0xff);
588 	wep->weCnt = cnt;
589 	wep->weAttributes = ATTR_WIN95;
590 	wep->weReserved1 = 0;
591 	wep->weChksum = chksum;
592 	wep->weReserved2 = 0;
593 
594 	/*
595 	 * Now convert the filename parts
596 	 */
597 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
598 		if (--unlen < 0)
599 			goto done;
600 		*cp++ = *un++;
601 		*cp++ = 0;
602 	}
603 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
604 		if (--unlen < 0)
605 			goto done;
606 		*cp++ = *un++;
607 		*cp++ = 0;
608 	}
609 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
610 		if (--unlen < 0)
611 			goto done;
612 		*cp++ = *un++;
613 		*cp++ = 0;
614 	}
615 	if (!unlen)
616 		wep->weCnt |= WIN_LAST;
617 	return unlen;
618 
619 done:
620 	*cp++ = 0;
621 	*cp++ = 0;
622 	wep->weCnt |= WIN_LAST;
623 	return 0;
624 }
625 
626 /*
627  * Compare our filename to the one in the Win95 entry
628  * Returns the checksum or -1 if no match
629  */
630 int
631 winChkName(un, unlen, wep, chksum)
632 	u_char *un;
633 	int unlen;
634 	struct winentry *wep;
635 	int chksum;
636 {
637 	u_int8_t *cp;
638 	int i;
639 
640 	/*
641 	 * First compare checksums
642 	 */
643 	if (wep->weCnt&WIN_LAST)
644 		chksum = wep->weChksum;
645 	else if (chksum != wep->weChksum)
646 		chksum = -1;
647 	if (chksum == -1)
648 		return -1;
649 
650 	/*
651 	 * Offset of this entry
652 	 */
653 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
654 	if ((unlen -= i) <= 0)
655 		return -1;
656 	un += i;
657 
658 	if ((wep->weCnt&WIN_LAST) && unlen > WIN_CHARS)
659 		return -1;
660 
661 	/*
662 	 * Compare the name parts
663 	 */
664 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
665 		if (--unlen < 0) {
666 			if (!*cp++ && !*cp)
667 				return chksum;
668 			return -1;
669 		}
670 		if (u2l[*cp++] != u2l[*un++] || *cp++)
671 			return -1;
672 	}
673 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
674 		if (--unlen < 0) {
675 			if (!*cp++ && !*cp)
676 				return chksum;
677 			return -1;
678 		}
679 		if (u2l[*cp++] != u2l[*un++] || *cp++)
680 			return -1;
681 	}
682 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
683 		if (--unlen < 0) {
684 			if (!*cp++ && !*cp)
685 				return chksum;
686 			return -1;
687 		}
688 		if (u2l[*cp++] != u2l[*un++] || *cp++)
689 			return -1;
690 	}
691 	return chksum;
692 }
693 
694 /*
695  * Convert Win95 filename to dirbuf.
696  * Returns the checksum or -1 if impossible
697  */
698 int
699 win2unixfn(wep, dp, chksum)
700 	struct winentry *wep;
701 	struct dirent *dp;
702 	int chksum;
703 {
704 	u_int8_t *cp;
705 	u_int8_t *np, *ep = dp->d_name + WIN_MAXLEN;
706 	int i;
707 
708 	if ((wep->weCnt&WIN_CNT) > howmany(WIN_MAXLEN, WIN_CHARS)
709 	    || !(wep->weCnt&WIN_CNT))
710 		return -1;
711 
712 	/*
713 	 * First compare checksums
714 	 */
715 	if (wep->weCnt&WIN_LAST) {
716 		chksum = wep->weChksum;
717 		/*
718 		 * This works even though d_namlen is one byte!
719 		 */
720 		dp->d_namlen = (wep->weCnt&WIN_CNT) * WIN_CHARS;
721 	} else if (chksum != wep->weChksum)
722 		chksum = -1;
723 	if (chksum == -1)
724 		return -1;
725 
726 	/*
727 	 * Offset of this entry
728 	 */
729 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
730 	np = (u_int8_t *)dp->d_name + i;
731 
732 	/*
733 	 * Convert the name parts
734 	 */
735 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
736 		switch (*np++ = *cp++) {
737 		case 0:
738 			dp->d_namlen -= sizeof(wep->wePart2)/2
739 			    + sizeof(wep->wePart3)/2 + i + 1;
740 			return chksum;
741 		case '/':
742 			np[-1] = 0;
743 			return -1;
744 		}
745 		/*
746 		 * The size comparison should result in the compiler
747 		 * optimizing the whole if away
748 		 */
749 		if (WIN_MAXLEN % WIN_CHARS < sizeof(wep->wePart1) / 2
750 		    && np > ep) {
751 			np[-1] = 0;
752 			return -1;
753 		}
754 		if (*cp++)
755 			return -1;
756 	}
757 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
758 		switch (*np++ = *cp++) {
759 		case 0:
760 			dp->d_namlen -= sizeof(wep->wePart3)/2 + i + 1;
761 			return chksum;
762 		case '/':
763 			np[-1] = 0;
764 			return -1;
765 		}
766 		/*
767 		 * The size comparisons should be optimized away
768 		 */
769 		if (WIN_MAXLEN % WIN_CHARS >= sizeof(wep->wePart1) / 2
770 		    && WIN_MAXLEN % WIN_CHARS < (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
771 		    && np > ep) {
772 			np[-1] = 0;
773 			return -1;
774 		}
775 		if (*cp++)
776 			return -1;
777 	}
778 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
779 		switch (*np++ = *cp++) {
780 		case 0:
781 			dp->d_namlen -= i + 1;
782 			return chksum;
783 		case '/':
784 			np[-1] = 0;
785 			return -1;
786 		}
787 		/*
788 		 * See above
789 		 */
790 		if (WIN_MAXLEN % WIN_CHARS >= (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
791 		    && np > ep) {
792 			np[-1] = 0;
793 			return -1;
794 		}
795 		if (*cp++)
796 			return -1;
797 	}
798 	return chksum;
799 }
800 
801 /*
802  * Compute the checksum of a DOS filename for Win95 use
803  */
804 u_int8_t
805 winChksum(name)
806 	u_int8_t *name;
807 {
808 	int i;
809 	u_int8_t s;
810 
811 	for (s = 0, i = 11; --i >= 0; s += *name++)
812 		s = (s << 7)|(s >> 1);
813 	return s;
814 }
815 
816 /*
817  * Determine the number of slots necessary for Win95 names
818  */
819 int
820 winSlotCnt(un, unlen)
821 	u_char *un;
822 	int unlen;
823 {
824 	for (un += unlen; unlen > 0; unlen--)
825 		if (*--un != ' ' && *un != '.')
826 			break;
827 	if (unlen > WIN_MAXLEN)
828 		return 0;
829 	return howmany(unlen, WIN_CHARS);
830 }
831