xref: /openbsd-src/sys/msdosfs/msdosfs_conv.c (revision d13be5d47e4149db2549a9828e244d59dbc43f15)
1 /*	$OpenBSD: msdosfs_conv.c,v 1.14 2009/08/13 22:34:29 jasper 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(struct timespec *tsp, u_int16_t *ddp, u_int16_t *dtp, u_int8_t *dhp)
98 {
99 	uint32_t t;
100 	uint32_t days;
101 	uint32_t inc;
102 	uint32_t year;
103 	uint32_t month;
104 	const u_short *months;
105 
106 	/*
107 	 * If the time from the last conversion is the same as now, then
108 	 * skip the computations and use the saved result.
109 	 */
110 	t = tsp->tv_sec - (tz.tz_minuteswest * 60)
111 	     /* +- daylight saving time correction */ ;
112 	t &= ~1;
113 	if (lasttime != t) {
114 		lasttime = t;
115 		lastdtime = (((t / 2) % 30) << DT_2SECONDS_SHIFT)
116 		    + (((t / 60) % 60) << DT_MINUTES_SHIFT)
117 		    + (((t / 3600) % 24) << DT_HOURS_SHIFT);
118 
119 		/*
120 		 * If the number of days since 1970 is the same as the last
121 		 * time we did the computation then skip all this leap year
122 		 * and month stuff.
123 		 */
124 		days = t / (24 * 60 * 60);
125 		if (days != lastday) {
126 			lastday = days;
127 			for (year = 1970;; year++) {
128 				inc = year & 0x03 ? 365 : 366;
129 				if (days < inc)
130 					break;
131 				days -= inc;
132 			}
133 			months = year & 0x03 ? regyear : leapyear;
134 			for (month = 0; month < 12; month++) {
135 				if (days < months[month])
136 					break;
137 				days -= months[month];
138 			}
139 			lastddate = ((days + 1) << DD_DAY_SHIFT)
140 			    + ((month + 1) << DD_MONTH_SHIFT);
141 			/*
142 			 * Remember dos's idea of time is relative to 1980.
143 			 * unix's is relative to 1970.  If somehow we get a
144 			 * time before 1980 then don't give totally crazy
145 			 * results.
146 			 */
147 			if (year > 1980)
148 				lastddate += (year - 1980) << DD_YEAR_SHIFT;
149 		}
150 	}
151 
152 	if (dtp != NULL)
153 		*dtp = lastdtime;
154 	if (dhp != NULL)
155 	        *dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;
156 
157 	*ddp = lastddate;
158 }
159 
160 /*
161  * The number of seconds between Jan 1, 1970 and Jan 1, 1980. In that
162  * interval there were 8 regular years and 2 leap years.
163  */
164 #define	SECONDSTO1980	(((8 * 365) + (2 * 366)) * (24 * 60 * 60))
165 
166 u_short lastdosdate;
167 uint32_t lastseconds;
168 
169 /*
170  * Convert from dos' idea of time to unix'. This will probably only be
171  * called from the stat(), and fstat() system calls and so probably need
172  * not be too efficient.
173  */
174 void
175 dos2unixtime(u_int dd, u_int dt, u_int dh, struct timespec *tsp)
176 {
177 	uint32_t seconds;
178 	uint32_t m, month;
179 	uint32_t y, year;
180 	uint32_t days;
181 	const u_short *months;
182 
183 	if (dd == 0) {
184 		/*
185 		 * Uninitialized field, return the epoch.
186 		 */
187 		tsp->tv_sec = 0;
188 		tsp->tv_nsec = 0;
189 		return;
190 	}
191 	seconds = ((dt & DT_2SECONDS_MASK) >> DT_2SECONDS_SHIFT) * 2
192 	    + ((dt & DT_MINUTES_MASK) >> DT_MINUTES_SHIFT) * 60
193 	    + ((dt & DT_HOURS_MASK) >> DT_HOURS_SHIFT) * 3600
194 	    + dh / 100;
195 	/*
196 	 * If the year, month, and day from the last conversion are the
197 	 * same then use the saved value.
198 	 */
199 	if (lastdosdate != dd) {
200 		lastdosdate = dd;
201 		days = 0;
202 		year = (dd & DD_YEAR_MASK) >> DD_YEAR_SHIFT;
203 		for (y = 0; y < year; y++)
204 			days += y & 0x03 ? 365 : 366;
205 		months = year & 0x03 ? regyear : leapyear;
206 		/*
207 		 * Prevent going from 0 to 0xffffffff in the following
208 		 * loop.
209 		 */
210 		month = (dd & DD_MONTH_MASK) >> DD_MONTH_SHIFT;
211 		if (month == 0) {
212 			printf("dos2unixtime(): month value out of range (%ld)\n",
213 			    month);
214 			month = 1;
215 		}
216 		for (m = 0; m < month - 1; m++)
217 			days += months[m];
218 		days += ((dd & DD_DAY_MASK) >> DD_DAY_SHIFT) - 1;
219 		lastseconds = (days * 24 * 60 * 60) + SECONDSTO1980;
220 	}
221 	tsp->tv_sec = seconds + lastseconds + (tz.tz_minuteswest * 60)
222 	     /* -+ daylight saving time correction */ ;
223 	tsp->tv_nsec = (dh % 100) * 10000000;
224 }
225 
226 static const u_char
227 unix2dos[256] = {
228 	0,    0,    0,    0,    0,    0,    0,    0,	/* 00-07 */
229 	0,    0,    0,    0,    0,    0,    0,    0,	/* 08-0f */
230 	0,    0,    0,    0,    0,    0,    0,    0,	/* 10-17 */
231 	0,    0,    0,    0,    0,    0,    0,    0,	/* 18-1f */
232 	0,    0x21, 0,    0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
233 	0x28, 0x29, 0,    0,    0,    0x2d, 0,    0,	/* 28-2f */
234 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
235 	0x38, 0x39, 0,    0,    0,    0,    0,    0,	/* 38-3f */
236 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
237 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
238 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
239 	0x58, 0x59, 0x5a, 0,    0,    0,    0x5e, 0x5f,	/* 58-5f */
240 	0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 60-67 */
241 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 68-6f */
242 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 70-77 */
243 	0x58, 0x59, 0x5a, 0x7b, 0,    0x7d, 0x7e, 0,	/* 78-7f */
244 	0,    0,    0,    0,    0,    0,    0,    0,	/* 80-87 */
245 	0,    0,    0,    0,    0,    0,    0,    0,	/* 88-8f */
246 	0,    0,    0,    0,    0,    0,    0,    0,	/* 90-97 */
247 	0,    0,    0,    0,    0,    0,    0,    0,	/* 98-9f */
248 	0,    0xad, 0xbd, 0x9c, 0xcf, 0xbe, 0xdd, 0xf5,	/* a0-a7 */
249 	0xf9, 0xb8, 0xa6, 0xae, 0xaa, 0xf0, 0xa9, 0xee,	/* a8-af */
250 	0xf8, 0xf1, 0xfd, 0xfc, 0xef, 0xe6, 0xf4, 0xfa,	/* b0-b7 */
251 	0xf7, 0xfb, 0xa7, 0xaf, 0xac, 0xab, 0xf3, 0xa8,	/* b8-bf */
252 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* c0-c7 */
253 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* c8-cf */
254 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0x9e,	/* d0-d7 */
255 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0xe1,	/* d8-df */
256 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* e0-e7 */
257 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* e8-ef */
258 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0xf6,	/* f0-f7 */
259 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0x98,	/* f8-ff */
260 };
261 
262 static const u_char
263 dos2unix[256] = {
264 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 00-07 */
265 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 08-0f */
266 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 10-17 */
267 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 18-1f */
268 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
269 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,	/* 28-2f */
270 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
271 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,	/* 38-3f */
272 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
273 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
274 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
275 	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,	/* 58-5f */
276 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,	/* 60-67 */
277 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,	/* 68-6f */
278 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,	/* 70-77 */
279 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,	/* 78-7f */
280 	0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7,	/* 80-87 */
281 	0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,	/* 88-8f */
282 	0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9,	/* 90-97 */
283 	0xff, 0xd6, 0xdc, 0xf8, 0xa3, 0xd8, 0xd7, 0x3f,	/* 98-9f */
284 	0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba,	/* a0-a7 */
285 	0xbf, 0xae, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,	/* a8-af */
286 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xc1, 0xc2, 0xc0,	/* b0-b7 */
287 	0xa9, 0x3f, 0x3f, 0x3f, 0x3f, 0xa2, 0xa5, 0x3f,	/* b8-bf */
288 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xe3, 0xc3,	/* c0-c7 */
289 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xa4,	/* c8-cf */
290 	0xf0, 0xd0, 0xca, 0xcb, 0xc8, 0x3f, 0xcd, 0xce,	/* d0-d7 */
291 	0xcf, 0x3f, 0x3f, 0x3f, 0x3f, 0xa6, 0xcc, 0x3f,	/* d8-df */
292 	0xd3, 0xdf, 0xd4, 0xd2, 0xf5, 0xd5, 0xb5, 0xfe,	/* e0-e7 */
293 	0xde, 0xda, 0xdb, 0xd9, 0xfd, 0xdd, 0xaf, 0x3f,	/* e8-ef */
294 	0xad, 0xb1, 0x3f, 0xbe, 0xb6, 0xa7, 0xf7, 0xb8,	/* f0-f7 */
295 	0xb0, 0xa8, 0xb7, 0xb9, 0xb3, 0xb2, 0x3f, 0x3f,	/* f8-ff */
296 };
297 
298 static const u_char
299 u2l[256] = {
300 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
301 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
302 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
303 	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
304 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 20-27 */
305 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 28-2f */
306 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 30-37 */
307 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 38-3f */
308 	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 40-47 */
309 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 48-4f */
310 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 50-57 */
311 	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 58-5f */
312 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 60-67 */
313 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 68-6f */
314 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 70-77 */
315 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 78-7f */
316 	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
317 	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
318 	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
319 	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
320 	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
321 	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
322 	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
323 	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
324 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
325 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
326 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
327 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
328 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
329 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
330 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
331 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
332 };
333 
334 /*
335  * DOS filenames are made of 2 parts, the name part and the extension part.
336  * The name part is 8 characters long and the extension part is 3
337  * characters long.  They may contain trailing blanks if the name or
338  * extension are not long enough to fill their respective fields.
339  */
340 
341 /*
342  * Convert a DOS filename to a unix filename. And, return the number of
343  * characters in the resulting unix filename excluding the terminating
344  * null.
345  */
346 int
347 dos2unixfn(u_char dn[11], u_char *un, int lower)
348 {
349 	int i;
350 	int thislong = 1;
351 	u_char c;
352 
353 	/*
354 	 * If first char of the filename is SLOT_E5 (0x05), then the real
355 	 * first char of the filename should be 0xe5. But, they couldn't
356 	 * just have a 0xe5 mean 0xe5 because that is used to mean a freed
357 	 * directory slot. Another dos quirk.
358 	 */
359 	if (*dn == SLOT_E5)
360 		c = dos2unix[0xe5];
361 	else
362 		c = dos2unix[*dn];
363 	*un++ = lower ? u2l[c] : c;
364 	dn++;
365 
366 	/*
367 	 * Copy the name portion into the unix filename string.
368 	 */
369 	for (i = 1; i < 8 && *dn != ' '; i++) {
370 		c = dos2unix[*dn++];
371 		*un++ = lower ? u2l[c] : c;
372 		thislong++;
373 	}
374 	dn += 8 - i;
375 
376 	/*
377 	 * Now, if there is an extension then put in a period and copy in
378 	 * the extension.
379 	 */
380 	if (*dn != ' ') {
381 		*un++ = '.';
382 		thislong++;
383 		for (i = 0; i < 3 && *dn != ' '; i++) {
384 			c = dos2unix[*dn++];
385 			*un++ = lower ? u2l[c] : c;
386 			thislong++;
387 		}
388 	}
389 	*un++ = 0;
390 
391 	return (thislong);
392 }
393 
394 /*
395  * Convert a unix filename to a DOS filename according to Win95 rules.
396  * If applicable and gen is not 0, it is inserted into the converted
397  * filename as a generation number.
398  * Returns
399  *	0 if name couldn't be converted
400  *	1 if the converted name is the same as the original
401  *	  (no long filename entry necessary for Win95)
402  *	2 if conversion was successful
403  *	3 if conversion was successful and generation number was inserted
404  */
405 int
406 unix2dosfn(u_char *un, u_char dn[12], int unlen, u_int gen)
407 {
408 	int i, j, l;
409 	int conv = 1;
410 	u_char *cp, *dp, *dp1;
411 	u_char gentext[6];
412 
413 	/*
414 	 * Fill the dos filename string with blanks. These are DOS's pad
415 	 * characters.
416 	 */
417 	for (i = 0; i < 11; i++)
418 		dn[i] = ' ';
419 	dn[11] = 0;
420 
421 	/*
422 	 * The filenames "." and ".." are handled specially, since they
423 	 * don't follow dos filename rules.
424 	 */
425 	if (un[0] == '.' && unlen == 1) {
426 		dn[0] = '.';
427 		return gen <= 1;
428 	}
429 	if (un[0] == '.' && un[1] == '.' && unlen == 2) {
430 		dn[0] = '.';
431 		dn[1] = '.';
432 		return gen <= 1;
433 	}
434 
435 	/*
436 	 * Filenames with only blanks and dots are not allowed!
437 	 */
438 	for (cp = un, i = unlen; --i >= 0; cp++)
439 		if (*cp != ' ' && *cp != '.')
440 			break;
441 	if (i < 0)
442 		return 0;
443 
444 	/*
445 	 * Now find the extension
446 	 * Note: dot as first char doesn't start extension
447 	 *	 and trailing dots and blanks are ignored
448 	 */
449 	dp = dp1 = 0;
450 	for (cp = un + 1, i = unlen - 1; --i >= 0;) {
451 		switch (*cp++) {
452 		case '.':
453 			if (!dp1)
454 				dp1 = cp;
455 			break;
456 		case ' ':
457 			break;
458 		default:
459 			if (dp1)
460 				dp = dp1;
461 			dp1 = 0;
462 			break;
463 		}
464 	}
465 
466 	/*
467 	 * Now convert it
468 	 */
469 	if (dp) {
470 		if (dp1)
471 			l = dp1 - dp;
472 		else
473 			l = unlen - (dp - un);
474 		for (i = 0, j = 8; i < l && j < 11; i++, j++) {
475 			if (dp[i] != (dn[j] = unix2dos[dp[i]])
476 			    && conv != 3)
477 				conv = 2;
478 			if (!dn[j]) {
479 				conv = 3;
480 				dn[j--] = ' ';
481 			}
482 		}
483 		if (i < l)
484 			conv = 3;
485 		dp--;
486 	} else {
487 		for (dp = cp; *--dp == ' ' || *dp == '.';);
488 		dp++;
489 	}
490 
491 	/*
492 	 * Now convert the rest of the name
493 	 */
494 	for (i = j = 0; un < dp && j < 8; i++, j++, un++) {
495 		if (*un != (dn[j] = unix2dos[*un])
496 		    && conv != 3)
497 			conv = 2;
498 		if (!dn[j]) {
499 			conv = 3;
500 			dn[j--] = ' ';
501 		}
502 	}
503 	if (un < dp)
504 		conv = 3;
505 	/*
506 	 * If we didn't have any chars in filename,
507 	 * generate a default
508 	 */
509 	if (!j)
510 		dn[0] = '_';
511 
512 	/*
513 	 * The first character cannot be E5,
514 	 * because that means a deleted entry
515 	 */
516 	if (dn[0] == 0xe5)
517 		dn[0] = SLOT_E5;
518 
519 	/*
520 	 * If there wasn't any char dropped,
521 	 * there is no place for generation numbers
522 	 */
523 	if (conv != 3) {
524 		if (gen > 1)
525 			return 0;
526 		return conv;
527 	}
528 
529 	/*
530 	 * Now insert the generation number into the filename part
531 	 */
532 	for (cp = gentext + sizeof(gentext); cp > gentext && gen; gen /= 10)
533 		*--cp = gen % 10 + '0';
534 	if (gen)
535 		return 0;
536 	for (i = 8; dn[--i] == ' ';);
537 	if (gentext + sizeof(gentext) - cp + 1 > 8 - i)
538 		i = 8 - (gentext + sizeof(gentext) - cp + 1);
539 	dn[i++] = '~';
540 	while (cp < gentext + sizeof(gentext))
541 		dn[i++] = *cp++;
542 	return 3;
543 }
544 
545 /*
546  * Create a Win95 long name directory entry
547  * Note: assumes that the filename is valid,
548  *	 i.e. doesn't consist solely of blanks and dots
549  */
550 int
551 unix2winfn(u_char *un, int unlen, struct winentry *wep, int cnt, int chksum)
552 {
553 	u_int8_t *cp;
554 	int i;
555 
556 	/*
557 	 * Drop trailing blanks and dots
558 	 */
559 	for (cp = un + unlen; *--cp == ' ' || *cp == '.'; unlen--);
560 
561 	un += (cnt - 1) * WIN_CHARS;
562 	unlen -= (cnt - 1) * WIN_CHARS;
563 
564 	/*
565 	 * Initialize winentry to some useful default
566 	 */
567 	for (cp = (u_int8_t *)wep, i = sizeof(*wep); --i >= 0; *cp++ = 0xff);
568 	wep->weCnt = cnt;
569 	wep->weAttributes = ATTR_WIN95;
570 	wep->weReserved1 = 0;
571 	wep->weChksum = chksum;
572 	wep->weReserved2 = 0;
573 
574 	/*
575 	 * Now convert the filename parts
576 	 */
577 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
578 		if (--unlen < 0)
579 			goto done;
580 		*cp++ = *un++;
581 		*cp++ = 0;
582 	}
583 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
584 		if (--unlen < 0)
585 			goto done;
586 		*cp++ = *un++;
587 		*cp++ = 0;
588 	}
589 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
590 		if (--unlen < 0)
591 			goto done;
592 		*cp++ = *un++;
593 		*cp++ = 0;
594 	}
595 	if (!unlen)
596 		wep->weCnt |= WIN_LAST;
597 	return unlen;
598 
599 done:
600 	*cp++ = 0;
601 	*cp++ = 0;
602 	wep->weCnt |= WIN_LAST;
603 	return 0;
604 }
605 
606 /*
607  * Compare our filename to the one in the Win95 entry
608  * Returns the checksum or -1 if no match
609  */
610 int
611 winChkName(u_char *un, int unlen, struct winentry *wep, int chksum)
612 {
613 	u_int8_t *cp;
614 	int i;
615 
616 	/*
617 	 * First compare checksums
618 	 */
619 	if (wep->weCnt&WIN_LAST)
620 		chksum = wep->weChksum;
621 	else if (chksum != wep->weChksum)
622 		chksum = -1;
623 	if (chksum == -1)
624 		return -1;
625 
626 	/*
627 	 * Offset of this entry
628 	 */
629 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
630 	if ((unlen -= i) <= 0)
631 		return -1;
632 	un += i;
633 
634 	if ((wep->weCnt&WIN_LAST) && unlen > WIN_CHARS)
635 		return -1;
636 
637 	/*
638 	 * Compare the name parts
639 	 */
640 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
641 		if (--unlen < 0) {
642 			if (!*cp++ && !*cp)
643 				return chksum;
644 			return -1;
645 		}
646 		if (u2l[*cp++] != u2l[*un++] || *cp++)
647 			return -1;
648 	}
649 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
650 		if (--unlen < 0) {
651 			if (!*cp++ && !*cp)
652 				return chksum;
653 			return -1;
654 		}
655 		if (u2l[*cp++] != u2l[*un++] || *cp++)
656 			return -1;
657 	}
658 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
659 		if (--unlen < 0) {
660 			if (!*cp++ && !*cp)
661 				return chksum;
662 			return -1;
663 		}
664 		if (u2l[*cp++] != u2l[*un++] || *cp++)
665 			return -1;
666 	}
667 	return chksum;
668 }
669 
670 /*
671  * Convert Win95 filename to dirbuf.
672  * Returns the checksum or -1 if impossible
673  */
674 int
675 win2unixfn(struct winentry *wep, struct dirent *dp, int chksum)
676 {
677 	u_int8_t *cp;
678 	u_int8_t *np, *ep = dp->d_name + WIN_MAXLEN;
679 	int i;
680 
681 	if ((wep->weCnt&WIN_CNT) > howmany(WIN_MAXLEN, WIN_CHARS)
682 	    || !(wep->weCnt&WIN_CNT))
683 		return -1;
684 
685 	/*
686 	 * First compare checksums
687 	 */
688 	if (wep->weCnt&WIN_LAST) {
689 		chksum = wep->weChksum;
690 		/*
691 		 * This works even though d_namlen is one byte!
692 		 */
693 		dp->d_namlen = (wep->weCnt&WIN_CNT) * WIN_CHARS;
694 	} else if (chksum != wep->weChksum)
695 		chksum = -1;
696 	if (chksum == -1)
697 		return -1;
698 
699 	/*
700 	 * Offset of this entry
701 	 */
702 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
703 	np = (u_int8_t *)dp->d_name + i;
704 
705 	/*
706 	 * Convert the name parts
707 	 */
708 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
709 		switch (*np++ = *cp++) {
710 		case 0:
711 			dp->d_namlen -= sizeof(wep->wePart2)/2
712 			    + sizeof(wep->wePart3)/2 + i + 1;
713 			return chksum;
714 		case '/':
715 			np[-1] = 0;
716 			return -1;
717 		}
718 		/*
719 		 * The size comparison should result in the compiler
720 		 * optimizing the whole if away
721 		 */
722 		if (WIN_MAXLEN % WIN_CHARS < sizeof(wep->wePart1) / 2
723 		    && np > ep) {
724 			np[-1] = 0;
725 			return -1;
726 		}
727 		if (*cp++)
728 			return -1;
729 	}
730 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
731 		switch (*np++ = *cp++) {
732 		case 0:
733 			dp->d_namlen -= sizeof(wep->wePart3)/2 + i + 1;
734 			return chksum;
735 		case '/':
736 			np[-1] = 0;
737 			return -1;
738 		}
739 		/*
740 		 * The size comparisons should be optimized away
741 		 */
742 		if (WIN_MAXLEN % WIN_CHARS >= sizeof(wep->wePart1) / 2
743 		    && WIN_MAXLEN % WIN_CHARS < (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
744 		    && np > ep) {
745 			np[-1] = 0;
746 			return -1;
747 		}
748 		if (*cp++)
749 			return -1;
750 	}
751 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
752 		switch (*np++ = *cp++) {
753 		case 0:
754 			dp->d_namlen -= i + 1;
755 			return chksum;
756 		case '/':
757 			np[-1] = 0;
758 			return -1;
759 		}
760 		/*
761 		 * See above
762 		 */
763 		if (WIN_MAXLEN % WIN_CHARS >= (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
764 		    && np > ep) {
765 			np[-1] = 0;
766 			return -1;
767 		}
768 		if (*cp++)
769 			return -1;
770 	}
771 	return chksum;
772 }
773 
774 /*
775  * Compute the checksum of a DOS filename for Win95 use
776  */
777 u_int8_t
778 winChksum(u_int8_t *name)
779 {
780 	int i;
781 	u_int8_t s;
782 
783 	for (s = 0, i = 11; --i >= 0; s += *name++)
784 		s = (s << 7)|(s >> 1);
785 	return s;
786 }
787 
788 /*
789  * Determine the number of slots necessary for Win95 names
790  */
791 int
792 winSlotCnt(u_char *un, int unlen)
793 {
794 	for (un += unlen; unlen > 0; unlen--)
795 		if (*--un != ' ' && *un != '.')
796 			break;
797 	if (unlen > WIN_MAXLEN)
798 		return 0;
799 	return howmany(unlen, WIN_CHARS);
800 }
801