xref: /openbsd/sys/msdosfs/msdosfs_conv.c (revision 8529ddd3)
1 /*	$OpenBSD: msdosfs_conv.c,v 1.18 2014/12/16 18:30:04 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 #include <sys/lock.h>
61 
62 /*
63  * MSDOSFS include files.
64  */
65 #include <msdosfs/direntry.h>
66 #include <msdosfs/denode.h>
67 
68 /*
69  * Days in each month in a regular year.
70  */
71 const u_short regyear[] = {
72 	31, 28, 31, 30, 31, 30,
73 	31, 31, 30, 31, 30, 31
74 };
75 
76 /*
77  * Days in each month in a leap year.
78  */
79 const u_short leapyear[] = {
80 	31, 29, 31, 30, 31, 30,
81 	31, 31, 30, 31, 30, 31
82 };
83 
84 /*
85  * Variables used to remember parts of the last time conversion.  Maybe we
86  * can avoid a full conversion.
87  */
88 time_t lasttime;
89 uint32_t lastday;
90 u_short lastddate;
91 u_short lastdtime;
92 
93 /*
94  * Convert the unix version of time to dos's idea of time to be used in
95  * file timestamps. The passed in unix time is assumed to be in GMT.
96  */
97 void
98 unix2dostime(struct timespec *tsp, u_int16_t *ddp, u_int16_t *dtp, u_int8_t *dhp)
99 {
100 	time_t t;
101 	uint32_t days;
102 	uint32_t inc;
103 	uint32_t year;
104 	uint32_t month;
105 	const u_short *months;
106 
107 	/*
108 	 * If the time from the last conversion is the same as now, then
109 	 * skip the computations and use the saved result.
110 	 */
111 	t = tsp->tv_sec - (tz.tz_minuteswest * 60)
112 	     /* +- daylight saving time correction */ ;
113 	t &= ~1;
114 	/*
115 	 * Before 1/1/1980 there is only a timeless void. After 12/31/2107
116 	 * there is only Cthulhu.
117 	 */
118 #define DOSEPOCH 315532800LL
119 #define DOSENDTIME 4354775999LL
120 	if (t < DOSEPOCH || t > DOSENDTIME)
121 		t = DOSEPOCH;
122 
123 	if (lasttime != t) {
124 		lasttime = t;
125 		lastdtime = (((t / 2) % 30) << DT_2SECONDS_SHIFT)
126 		    + (((t / 60) % 60) << DT_MINUTES_SHIFT)
127 		    + (((t / 3600) % 24) << DT_HOURS_SHIFT);
128 
129 		/*
130 		 * If the number of days since 1970 is the same as the last
131 		 * time we did the computation then skip all this leap year
132 		 * and month stuff.
133 		 */
134 		days = t / (24 * 60 * 60);
135 		if (days != lastday) {
136 			lastday = days;
137 			for (year = 1970;; year++) {
138 				inc = year & 0x03 ? 365 : 366;
139 				if (days < inc)
140 					break;
141 				days -= inc;
142 			}
143 			months = year & 0x03 ? regyear : leapyear;
144 			for (month = 0; month < 12; month++) {
145 				if (days < months[month])
146 					break;
147 				days -= months[month];
148 			}
149 			lastddate = ((days + 1) << DD_DAY_SHIFT)
150 			    + ((month + 1) << DD_MONTH_SHIFT);
151 			/*
152 			 * Remember dos's idea of time is relative to 1980.
153 			 * unix's is relative to 1970.  If somehow we get a
154 			 * time before 1980 then don't give totally crazy
155 			 * results.
156 			 */
157 			if (year > 1980)
158 				lastddate += (year - 1980) << DD_YEAR_SHIFT;
159 		}
160 	}
161 
162 	if (dtp != NULL)
163 		*dtp = lastdtime;
164 	if (dhp != NULL)
165 	        *dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;
166 
167 	*ddp = lastddate;
168 }
169 
170 /*
171  * The number of seconds between Jan 1, 1970 and Jan 1, 1980. In that
172  * interval there were 8 regular years and 2 leap years.
173  */
174 #define	SECONDSTO1980	(((8 * 365) + (2 * 366)) * (24 * 60 * 60))
175 
176 u_short lastdosdate;
177 uint32_t lastseconds;
178 
179 /*
180  * Convert from dos' idea of time to unix'. This will probably only be
181  * called from the stat(), and fstat() system calls and so probably need
182  * not be too efficient.
183  */
184 void
185 dos2unixtime(u_int dd, u_int dt, u_int dh, struct timespec *tsp)
186 {
187 	uint32_t seconds;
188 	uint32_t m, month;
189 	uint32_t y, year;
190 	uint32_t days;
191 	const u_short *months;
192 
193 	if (dd == 0) {
194 		/*
195 		 * Uninitialized field, return the epoch.
196 		 */
197 		tsp->tv_sec = 0;
198 		tsp->tv_nsec = 0;
199 		return;
200 	}
201 	seconds = ((dt & DT_2SECONDS_MASK) >> DT_2SECONDS_SHIFT) * 2
202 	    + ((dt & DT_MINUTES_MASK) >> DT_MINUTES_SHIFT) * 60
203 	    + ((dt & DT_HOURS_MASK) >> DT_HOURS_SHIFT) * 3600
204 	    + dh / 100;
205 	/*
206 	 * If the year, month, and day from the last conversion are the
207 	 * same then use the saved value.
208 	 */
209 	if (lastdosdate != dd) {
210 		lastdosdate = dd;
211 		days = 0;
212 		year = (dd & DD_YEAR_MASK) >> DD_YEAR_SHIFT;
213 		for (y = 0; y < year; y++)
214 			days += y & 0x03 ? 365 : 366;
215 		months = year & 0x03 ? regyear : leapyear;
216 		/*
217 		 * Prevent going from 0 to 0xffffffff in the following
218 		 * loop.
219 		 */
220 		month = (dd & DD_MONTH_MASK) >> DD_MONTH_SHIFT;
221 		if (month == 0) {
222 			printf("dos2unixtime(): month value out of range (%u)\n",
223 			    month);
224 			month = 1;
225 		}
226 		for (m = 0; m < month - 1; m++)
227 			days += months[m];
228 		days += ((dd & DD_DAY_MASK) >> DD_DAY_SHIFT) - 1;
229 		lastseconds = (days * 24 * 60 * 60) + SECONDSTO1980;
230 	}
231 	tsp->tv_sec = seconds + lastseconds + (tz.tz_minuteswest * 60)
232 	     /* -+ daylight saving time correction */ ;
233 	tsp->tv_nsec = (dh % 100) * 10000000;
234 }
235 
236 static const u_char
237 unix2dos[256] = {
238 	0,    0,    0,    0,    0,    0,    0,    0,	/* 00-07 */
239 	0,    0,    0,    0,    0,    0,    0,    0,	/* 08-0f */
240 	0,    0,    0,    0,    0,    0,    0,    0,	/* 10-17 */
241 	0,    0,    0,    0,    0,    0,    0,    0,	/* 18-1f */
242 	0,    0x21, 0,    0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
243 	0x28, 0x29, 0,    0,    0,    0x2d, 0,    0,	/* 28-2f */
244 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
245 	0x38, 0x39, 0,    0,    0,    0,    0,    0,	/* 38-3f */
246 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
247 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
248 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
249 	0x58, 0x59, 0x5a, 0,    0,    0,    0x5e, 0x5f,	/* 58-5f */
250 	0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 60-67 */
251 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 68-6f */
252 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 70-77 */
253 	0x58, 0x59, 0x5a, 0x7b, 0,    0x7d, 0x7e, 0,	/* 78-7f */
254 	0,    0,    0,    0,    0,    0,    0,    0,	/* 80-87 */
255 	0,    0,    0,    0,    0,    0,    0,    0,	/* 88-8f */
256 	0,    0,    0,    0,    0,    0,    0,    0,	/* 90-97 */
257 	0,    0,    0,    0,    0,    0,    0,    0,	/* 98-9f */
258 	0,    0xad, 0xbd, 0x9c, 0xcf, 0xbe, 0xdd, 0xf5,	/* a0-a7 */
259 	0xf9, 0xb8, 0xa6, 0xae, 0xaa, 0xf0, 0xa9, 0xee,	/* a8-af */
260 	0xf8, 0xf1, 0xfd, 0xfc, 0xef, 0xe6, 0xf4, 0xfa,	/* b0-b7 */
261 	0xf7, 0xfb, 0xa7, 0xaf, 0xac, 0xab, 0xf3, 0xa8,	/* b8-bf */
262 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* c0-c7 */
263 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* c8-cf */
264 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0x9e,	/* d0-d7 */
265 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0xe1,	/* d8-df */
266 	0xb7, 0xb5, 0xb6, 0xc7, 0x8e, 0x8f, 0x92, 0x80,	/* e0-e7 */
267 	0xd4, 0x90, 0xd2, 0xd3, 0xde, 0xd6, 0xd7, 0xd8,	/* e8-ef */
268 	0xd1, 0xa5, 0xe3, 0xe0, 0xe2, 0xe5, 0x99, 0xf6,	/* f0-f7 */
269 	0x9d, 0xeb, 0xe9, 0xea, 0x9a, 0xed, 0xe8, 0x98,	/* f8-ff */
270 };
271 
272 static const u_char
273 dos2unix[256] = {
274 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 00-07 */
275 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 08-0f */
276 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 10-17 */
277 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,	/* 18-1f */
278 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,	/* 20-27 */
279 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,	/* 28-2f */
280 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	/* 30-37 */
281 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,	/* 38-3f */
282 	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	/* 40-47 */
283 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,	/* 48-4f */
284 	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	/* 50-57 */
285 	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,	/* 58-5f */
286 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,	/* 60-67 */
287 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,	/* 68-6f */
288 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,	/* 70-77 */
289 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,	/* 78-7f */
290 	0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7,	/* 80-87 */
291 	0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,	/* 88-8f */
292 	0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9,	/* 90-97 */
293 	0xff, 0xd6, 0xdc, 0xf8, 0xa3, 0xd8, 0xd7, 0x3f,	/* 98-9f */
294 	0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba,	/* a0-a7 */
295 	0xbf, 0xae, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,	/* a8-af */
296 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xc1, 0xc2, 0xc0,	/* b0-b7 */
297 	0xa9, 0x3f, 0x3f, 0x3f, 0x3f, 0xa2, 0xa5, 0x3f,	/* b8-bf */
298 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xe3, 0xc3,	/* c0-c7 */
299 	0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0xa4,	/* c8-cf */
300 	0xf0, 0xd0, 0xca, 0xcb, 0xc8, 0x3f, 0xcd, 0xce,	/* d0-d7 */
301 	0xcf, 0x3f, 0x3f, 0x3f, 0x3f, 0xa6, 0xcc, 0x3f,	/* d8-df */
302 	0xd3, 0xdf, 0xd4, 0xd2, 0xf5, 0xd5, 0xb5, 0xfe,	/* e0-e7 */
303 	0xde, 0xda, 0xdb, 0xd9, 0xfd, 0xdd, 0xaf, 0x3f,	/* e8-ef */
304 	0xad, 0xb1, 0x3f, 0xbe, 0xb6, 0xa7, 0xf7, 0xb8,	/* f0-f7 */
305 	0xb0, 0xa8, 0xb7, 0xb9, 0xb3, 0xb2, 0x3f, 0x3f,	/* f8-ff */
306 };
307 
308 static const u_char
309 u2l[256] = {
310 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 00-07 */
311 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 08-0f */
312 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 10-17 */
313 	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 18-1f */
314 	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 20-27 */
315 	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 28-2f */
316 	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 30-37 */
317 	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 38-3f */
318 	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 40-47 */
319 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 48-4f */
320 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 50-57 */
321 	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 58-5f */
322 	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 60-67 */
323 	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 68-6f */
324 	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 70-77 */
325 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 78-7f */
326 	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 80-87 */
327 	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 88-8f */
328 	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 90-97 */
329 	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 98-9f */
330 	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* a0-a7 */
331 	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* a8-af */
332 	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* b0-b7 */
333 	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* b8-bf */
334 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* c0-c7 */
335 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* c8-cf */
336 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xd7, /* d0-d7 */
337 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xdf, /* d8-df */
338 	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* e0-e7 */
339 	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* e8-ef */
340 	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* f0-f7 */
341 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* f8-ff */
342 };
343 
344 /*
345  * DOS filenames are made of 2 parts, the name part and the extension part.
346  * The name part is 8 characters long and the extension part is 3
347  * characters long.  They may contain trailing blanks if the name or
348  * extension are not long enough to fill their respective fields.
349  */
350 
351 /*
352  * Convert a DOS filename to a unix filename. And, return the number of
353  * characters in the resulting unix filename excluding the terminating
354  * null.
355  */
356 int
357 dos2unixfn(u_char dn[11], u_char *un, int lower)
358 {
359 	int i;
360 	int thislong = 1;
361 	u_char c;
362 
363 	/*
364 	 * If first char of the filename is SLOT_E5 (0x05), then the real
365 	 * first char of the filename should be 0xe5. But, they couldn't
366 	 * just have a 0xe5 mean 0xe5 because that is used to mean a freed
367 	 * directory slot. Another dos quirk.
368 	 */
369 	if (*dn == SLOT_E5)
370 		c = dos2unix[0xe5];
371 	else
372 		c = dos2unix[*dn];
373 	*un++ = lower ? u2l[c] : c;
374 	dn++;
375 
376 	/*
377 	 * Copy the name portion into the unix filename string.
378 	 */
379 	for (i = 1; i < 8 && *dn != ' '; i++) {
380 		c = dos2unix[*dn++];
381 		*un++ = lower ? u2l[c] : c;
382 		thislong++;
383 	}
384 	dn += 8 - i;
385 
386 	/*
387 	 * Now, if there is an extension then put in a period and copy in
388 	 * the extension.
389 	 */
390 	if (*dn != ' ') {
391 		*un++ = '.';
392 		thislong++;
393 		for (i = 0; i < 3 && *dn != ' '; i++) {
394 			c = dos2unix[*dn++];
395 			*un++ = lower ? u2l[c] : c;
396 			thislong++;
397 		}
398 	}
399 	*un++ = 0;
400 
401 	return (thislong);
402 }
403 
404 /*
405  * Convert a unix filename to a DOS filename according to Win95 rules.
406  * If applicable and gen is not 0, it is inserted into the converted
407  * filename as a generation number.
408  * Returns
409  *	0 if name couldn't be converted
410  *	1 if the converted name is the same as the original
411  *	  (no long filename entry necessary for Win95)
412  *	2 if conversion was successful
413  *	3 if conversion was successful and generation number was inserted
414  */
415 int
416 unix2dosfn(u_char *un, u_char dn[11], int unlen, u_int gen)
417 {
418 	int i, j, l;
419 	int conv = 1;
420 	u_char *cp, *dp, *dp1;
421 	u_char gentext[6];
422 
423 	/*
424 	 * Fill the dos filename string with blanks. These are DOS's pad
425 	 * characters.
426 	 */
427 	for (i = 0; i < 11; i++)
428 		dn[i] = ' ';
429 
430 	/*
431 	 * The filenames "." and ".." are handled specially, since they
432 	 * don't follow dos filename rules.
433 	 */
434 	if (un[0] == '.' && unlen == 1) {
435 		dn[0] = '.';
436 		return gen <= 1;
437 	}
438 	if (un[0] == '.' && un[1] == '.' && unlen == 2) {
439 		dn[0] = '.';
440 		dn[1] = '.';
441 		return gen <= 1;
442 	}
443 
444 	/*
445 	 * Filenames with only blanks and dots are not allowed!
446 	 */
447 	for (cp = un, i = unlen; --i >= 0; cp++)
448 		if (*cp != ' ' && *cp != '.')
449 			break;
450 	if (i < 0)
451 		return 0;
452 
453 	/*
454 	 * Now find the extension
455 	 * Note: dot as first char doesn't start extension
456 	 *	 and trailing dots and blanks are ignored
457 	 */
458 	dp = dp1 = 0;
459 	for (cp = un + 1, i = unlen - 1; --i >= 0;) {
460 		switch (*cp++) {
461 		case '.':
462 			if (!dp1)
463 				dp1 = cp;
464 			break;
465 		case ' ':
466 			break;
467 		default:
468 			if (dp1)
469 				dp = dp1;
470 			dp1 = 0;
471 			break;
472 		}
473 	}
474 
475 	/*
476 	 * Now convert it
477 	 */
478 	if (dp) {
479 		if (dp1)
480 			l = dp1 - dp;
481 		else
482 			l = unlen - (dp - un);
483 		for (i = 0, j = 8; i < l && j < 11; i++, j++) {
484 			if (dp[i] != (dn[j] = unix2dos[dp[i]])
485 			    && conv != 3)
486 				conv = 2;
487 			if (!dn[j]) {
488 				conv = 3;
489 				dn[j--] = ' ';
490 			}
491 		}
492 		if (i < l)
493 			conv = 3;
494 		dp--;
495 	} else {
496 		for (dp = cp; *--dp == ' ' || *dp == '.';);
497 		dp++;
498 	}
499 
500 	/*
501 	 * Now convert the rest of the name
502 	 */
503 	for (i = j = 0; un < dp && j < 8; i++, j++, un++) {
504 		if (*un != (dn[j] = unix2dos[*un])
505 		    && conv != 3)
506 			conv = 2;
507 		if (!dn[j]) {
508 			conv = 3;
509 			dn[j--] = ' ';
510 		}
511 	}
512 	if (un < dp)
513 		conv = 3;
514 	/*
515 	 * If we didn't have any chars in filename,
516 	 * generate a default
517 	 */
518 	if (!j)
519 		dn[0] = '_';
520 
521 	/*
522 	 * The first character cannot be E5,
523 	 * because that means a deleted entry
524 	 */
525 	if (dn[0] == 0xe5)
526 		dn[0] = SLOT_E5;
527 
528 	/*
529 	 * If there wasn't any char dropped,
530 	 * there is no place for generation numbers
531 	 */
532 	if (conv != 3) {
533 		if (gen > 1)
534 			return 0;
535 		return conv;
536 	}
537 
538 	/*
539 	 * Now insert the generation number into the filename part
540 	 */
541 	for (cp = gentext + sizeof(gentext); cp > gentext && gen; gen /= 10)
542 		*--cp = gen % 10 + '0';
543 	if (gen)
544 		return 0;
545 	for (i = 8; dn[--i] == ' ';);
546 	if (gentext + sizeof(gentext) - cp + 1 > 8 - i)
547 		i = 8 - (gentext + sizeof(gentext) - cp + 1);
548 	dn[i++] = '~';
549 	while (cp < gentext + sizeof(gentext))
550 		dn[i++] = *cp++;
551 	return 3;
552 }
553 
554 /*
555  * Create a Win95 long name directory entry
556  * Note: assumes that the filename is valid,
557  *	 i.e. doesn't consist solely of blanks and dots
558  */
559 int
560 unix2winfn(u_char *un, int unlen, struct winentry *wep, int cnt, int chksum)
561 {
562 	u_int8_t *cp;
563 	int i;
564 
565 	/*
566 	 * Drop trailing blanks and dots
567 	 */
568 	for (cp = un + unlen; *--cp == ' ' || *cp == '.'; unlen--);
569 
570 	un += (cnt - 1) * WIN_CHARS;
571 	unlen -= (cnt - 1) * WIN_CHARS;
572 
573 	/*
574 	 * Initialize winentry to some useful default
575 	 */
576 	for (cp = (u_int8_t *)wep, i = sizeof(*wep); --i >= 0; *cp++ = 0xff);
577 	wep->weCnt = cnt;
578 	wep->weAttributes = ATTR_WIN95;
579 	wep->weReserved1 = 0;
580 	wep->weChksum = chksum;
581 	wep->weReserved2 = 0;
582 
583 	/*
584 	 * Now convert the filename parts
585 	 */
586 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
587 		if (--unlen < 0)
588 			goto done;
589 		*cp++ = *un++;
590 		*cp++ = 0;
591 	}
592 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
593 		if (--unlen < 0)
594 			goto done;
595 		*cp++ = *un++;
596 		*cp++ = 0;
597 	}
598 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
599 		if (--unlen < 0)
600 			goto done;
601 		*cp++ = *un++;
602 		*cp++ = 0;
603 	}
604 	if (!unlen)
605 		wep->weCnt |= WIN_LAST;
606 	return unlen;
607 
608 done:
609 	*cp++ = 0;
610 	*cp++ = 0;
611 	wep->weCnt |= WIN_LAST;
612 	return 0;
613 }
614 
615 /*
616  * Compare our filename to the one in the Win95 entry
617  * Returns the checksum or -1 if no match
618  */
619 int
620 winChkName(u_char *un, int unlen, struct winentry *wep, int chksum)
621 {
622 	u_int8_t *cp;
623 	int i;
624 
625 	/*
626 	 * First compare checksums
627 	 */
628 	if (wep->weCnt&WIN_LAST)
629 		chksum = wep->weChksum;
630 	else if (chksum != wep->weChksum)
631 		chksum = -1;
632 	if (chksum == -1)
633 		return -1;
634 
635 	/*
636 	 * Offset of this entry
637 	 */
638 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
639 	if ((unlen -= i) <= 0)
640 		return -1;
641 	un += i;
642 
643 	if ((wep->weCnt&WIN_LAST) && unlen > WIN_CHARS)
644 		return -1;
645 
646 	/*
647 	 * Compare the name parts
648 	 */
649 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/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->wePart2, i = sizeof(wep->wePart2)/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 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
668 		if (--unlen < 0) {
669 			if (!*cp++ && !*cp)
670 				return chksum;
671 			return -1;
672 		}
673 		if (u2l[*cp++] != u2l[*un++] || *cp++)
674 			return -1;
675 	}
676 	return chksum;
677 }
678 
679 /*
680  * Convert Win95 filename to dirbuf.
681  * Returns the checksum or -1 if impossible
682  */
683 int
684 win2unixfn(struct winentry *wep, struct dirent *dp, int chksum)
685 {
686 	u_int8_t *cp;
687 	u_int8_t *np, *ep = dp->d_name + WIN_MAXLEN;
688 	int i;
689 
690 	if ((wep->weCnt&WIN_CNT) > howmany(WIN_MAXLEN, WIN_CHARS)
691 	    || !(wep->weCnt&WIN_CNT))
692 		return -1;
693 
694 	/*
695 	 * First compare checksums
696 	 */
697 	if (wep->weCnt&WIN_LAST) {
698 		chksum = wep->weChksum;
699 		/*
700 		 * This works even though d_namlen is one byte!
701 		 */
702 		dp->d_namlen = (wep->weCnt&WIN_CNT) * WIN_CHARS;
703 	} else if (chksum != wep->weChksum)
704 		chksum = -1;
705 	if (chksum == -1)
706 		return -1;
707 
708 	/*
709 	 * Offset of this entry
710 	 */
711 	i = ((wep->weCnt&WIN_CNT) - 1) * WIN_CHARS;
712 	np = (u_int8_t *)dp->d_name + i;
713 
714 	/*
715 	 * Convert the name parts
716 	 */
717 	for (cp = wep->wePart1, i = sizeof(wep->wePart1)/2; --i >= 0;) {
718 		switch (*np++ = *cp++) {
719 		case 0:
720 			dp->d_namlen -= sizeof(wep->wePart2)/2
721 			    + sizeof(wep->wePart3)/2 + i + 1;
722 			return chksum;
723 		case '/':
724 			np[-1] = 0;
725 			return -1;
726 		}
727 		/*
728 		 * The size comparison should result in the compiler
729 		 * optimizing the whole if away
730 		 */
731 		if (WIN_MAXLEN % WIN_CHARS < sizeof(wep->wePart1) / 2
732 		    && np > ep) {
733 			np[-1] = 0;
734 			return -1;
735 		}
736 		if (*cp++)
737 			return -1;
738 	}
739 	for (cp = wep->wePart2, i = sizeof(wep->wePart2)/2; --i >= 0;) {
740 		switch (*np++ = *cp++) {
741 		case 0:
742 			dp->d_namlen -= sizeof(wep->wePart3)/2 + i + 1;
743 			return chksum;
744 		case '/':
745 			np[-1] = 0;
746 			return -1;
747 		}
748 		/*
749 		 * The size comparisons should be optimized away
750 		 */
751 		if (WIN_MAXLEN % WIN_CHARS >= sizeof(wep->wePart1) / 2
752 		    && WIN_MAXLEN % WIN_CHARS < (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
753 		    && np > ep) {
754 			np[-1] = 0;
755 			return -1;
756 		}
757 		if (*cp++)
758 			return -1;
759 	}
760 	for (cp = wep->wePart3, i = sizeof(wep->wePart3)/2; --i >= 0;) {
761 		switch (*np++ = *cp++) {
762 		case 0:
763 			dp->d_namlen -= i + 1;
764 			return chksum;
765 		case '/':
766 			np[-1] = 0;
767 			return -1;
768 		}
769 		/*
770 		 * See above
771 		 */
772 		if (WIN_MAXLEN % WIN_CHARS >= (sizeof(wep->wePart1) + sizeof(wep->wePart2)) / 2
773 		    && np > ep) {
774 			np[-1] = 0;
775 			return -1;
776 		}
777 		if (*cp++)
778 			return -1;
779 	}
780 	return chksum;
781 }
782 
783 /*
784  * Compute the checksum of a DOS filename for Win95 use
785  */
786 u_int8_t
787 winChksum(u_int8_t *name)
788 {
789 	int i;
790 	u_int8_t s;
791 
792 	for (s = 0, i = 11; --i >= 0; s += *name++)
793 		s = (s << 7)|(s >> 1);
794 	return s;
795 }
796 
797 /*
798  * Determine the number of slots necessary for Win95 names
799  */
800 int
801 winSlotCnt(u_char *un, int unlen)
802 {
803 	for (un += unlen; unlen > 0; unlen--)
804 		if (*--un != ' ' && *un != '.')
805 			break;
806 	if (unlen > WIN_MAXLEN)
807 		return 0;
808 	return howmany(unlen, WIN_CHARS);
809 }
810