xref: /illumos-gate/usr/src/uts/common/fs/pcfs/pc_subr.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Copyright (c) 1980 Regents of the University of California.
28  * All rights reserved. The Berkeley software License Agreement
29  * specifies the terms and conditions for redistribution.
30  */
31 
32 #ifndef KERNEL
33 #define	KERNEL
34 #endif
35 
36 #include <sys/param.h>
37 #include <sys/time.h>
38 #include <sys/conf.h>
39 #include <sys/sysmacros.h>
40 #include <sys/vfs.h>
41 #include <sys/debug.h>
42 #include <sys/errno.h>
43 #include <sys/cmn_err.h>
44 #include <sys/ddi.h>
45 #include <sys/sunddi.h>
46 #include <sys/byteorder.h>
47 #include <sys/types.h>
48 #include <sys/fs/pc_fs.h>
49 #include <sys/fs/pc_label.h>
50 #include <sys/fs/pc_dir.h>
51 #include <sys/fs/pc_node.h>
52 
53 /*
54  * Convert time between DOS formats:
55  *	- years since 1980
56  *	- months/days/hours/minutes/seconds, local TZ
57  * and the UNIX format (seconds since 01/01/1970, 00:00:00 UT).
58  *
59  * Timezones are adjusted for via mount option arg (secondswest),
60  * but daylight savings time corrections are not made. Calculated
61  * time may therefore end up being wrong by an hour, but this:
62  *	a) will happen as well if media is interchanged between
63  *	   two DOS/Windows-based systems that use different
64  *	   timezone settings
65  *	b) is the best option we have unless we decide to put
66  *	   a full ctime(3C) framework into the kernel, including
67  *	   all conversion tables - AND keeping them current ...
68  */
69 
70 int pc_tvtopct(timestruc_t *, struct pctime *);
71 void pc_pcttotv(struct pctime *, int64_t *);
72 
73 /*
74  * Macros/Definitons required to convert between DOS-style and
75  * UNIX-style time recording.
76  * DOS year zero is 1980.
77  */
78 static int daysinmonth[] =
79 	    { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
80 
81 #define	YEAR_ZERO	1980
82 #define	YZ_SECS	(((8 * 365) + (2 * 366)) * 86400)
83 #define	FAT_ENDOFTIME	\
84 	LE_16(23 << HOURSHIFT | 59 << MINSHIFT | (59/2) << SECSHIFT)
85 #define	FAT_ENDOFDATE	\
86 	LE_16(127 << YEARSHIFT | 12 << MONSHIFT | 31 << DAYSHIFT)
87 #define	leap_year(y) \
88 	(((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
89 
90 #define	YEN	"\xc2\xa5"	/* Yen Sign UTF-8 character */
91 #define	LRO	"\xe2\x80\xad"	/* Left-To-Right Override UTF-8 character */
92 #define	RLO	"\xe2\x80\xae"	/* Right-To-Left Override UTF-8 character */
93 
94 static int
95 days_in_year(int y)
96 {
97 	return (leap_year((y)) ? 366 : 365);
98 }
99 
100 static int
101 days_in_month(int m, int y)
102 {
103 	if (m == 2 && leap_year(y))
104 		return (29);
105 	else
106 		return (daysinmonth[m-1]);
107 }
108 
109 struct pcfs_args pc_tz; /* this is set by pcfs_mount */
110 
111 /*
112  * Convert time from UNIX to DOS format.
113  * Return EOVERFLOW in case no valid DOS time representation
114  * exists for the given UNIX time.
115  */
116 int
117 pc_tvtopct(
118 	timestruc_t	*tvp,		/* UNIX time input */
119 	struct pctime *pctp)		/* pctime output */
120 {
121 	uint_t year, month, day, hour, min, sec;
122 	int64_t unixtime;
123 
124 	unixtime = (int64_t)tvp->tv_sec;
125 	unixtime -= YZ_SECS;
126 	unixtime -= pc_tz.secondswest;
127 	if (unixtime <= 0) {
128 		/*
129 		 * "before beginning of all time" for DOS ...
130 		 */
131 		return (EOVERFLOW);
132 	}
133 	for (year = YEAR_ZERO; unixtime >= days_in_year(year) * 86400;
134 	    year++)
135 		unixtime -= 86400 * days_in_year(year);
136 
137 	if (year > 127 + YEAR_ZERO) {
138 		/*
139 		 * "past end of all time" for DOS - can happen
140 		 * on a 64bit kernel via utimes() syscall ...
141 		 */
142 		return (EOVERFLOW);
143 	}
144 
145 	for (month = 1; unixtime >= 86400 * days_in_month(month, year);
146 	    month++)
147 		unixtime -= 86400 * days_in_month(month, year);
148 
149 	year -= YEAR_ZERO;
150 
151 	day = (int)(unixtime / 86400);
152 	unixtime -= 86400 * day++;	/* counting starts at 1 */
153 
154 	hour = (int)(unixtime / 3600);
155 	unixtime -= 3600 * hour;
156 
157 	min = (int)(unixtime / 60);
158 	unixtime -= 60 * min;
159 
160 	sec = (int)unixtime;
161 
162 	PC_DPRINTF3(1, "ux2pc date: %d.%d.%d\n", day, month, YEAR_ZERO + year);
163 	PC_DPRINTF3(1, "ux2pc time: %dh%dm%ds\n", hour, min, sec);
164 	PC_DPRINTF1(1, "ux2pc unixtime: %lld\n", (long long)(unixtime));
165 
166 	ASSERT(year >= 0 && year < 128);
167 	ASSERT(month >= 1 && month <= 12);
168 	ASSERT(day >= 1 && day <= days_in_month(month, year));
169 	ASSERT(hour < 24);
170 	ASSERT(min < 60);
171 	ASSERT(sec < 60);
172 
173 	pctp->pct_time =
174 	    LE_16(hour << HOURSHIFT | min << MINSHIFT | (sec / 2) << SECSHIFT);
175 	pctp->pct_date =
176 	    LE_16(year << YEARSHIFT | month << MONSHIFT | day << DAYSHIFT);
177 
178 	return (0);
179 }
180 
181 /*
182  * Convert time from DOS to UNIX time format.
183  * Since FAT timestamps cannot be expressed in 32bit time_t,
184  * the calculation is performed using 64bit values. It's up to
185  * the caller to decide what to do for out-of-UNIX-range values.
186  */
187 void
188 pc_pcttotv(
189 	struct pctime *pctp,		/* DOS time input */
190 	int64_t *unixtime)		/* caller converts to time_t */
191 {
192 	uint_t year, month, day, hour, min, sec;
193 
194 	sec = 2 * ((LE_16(pctp->pct_time) >> SECSHIFT) & SECMASK);
195 	min = (LE_16(pctp->pct_time) >> MINSHIFT) & MINMASK;
196 	hour = (LE_16(pctp->pct_time) >> HOURSHIFT) & HOURMASK;
197 	day = (LE_16(pctp->pct_date) >> DAYSHIFT) & DAYMASK;
198 	month = (LE_16(pctp->pct_date) >> MONSHIFT) & MONMASK;
199 	year = (LE_16(pctp->pct_date) >> YEARSHIFT) & YEARMASK;
200 	year += YEAR_ZERO;
201 
202 	/*
203 	 * Basic sanity checks. The FAT timestamp bitfields allow for
204 	 * impossible dates/times - return the "FAT epoch" for these.
205 	 */
206 	if (pctp->pct_date == 0) {
207 		year = YEAR_ZERO;
208 		month = 1;
209 		day = 1;
210 	}
211 	if (month > 12 || month < 1 ||
212 	    day < 1 || day > days_in_month(month, year) ||
213 	    hour > 23 || min > 59 || sec > 59) {
214 		cmn_err(CE_NOTE, "impossible FAT timestamp, "
215 		    "d/m/y %d/%d/%d, h:m:s %d:%d:%d",
216 		    day, month, year, hour, min, sec);
217 		*unixtime = YZ_SECS + pc_tz.secondswest;
218 		return;
219 	}
220 
221 	PC_DPRINTF3(1, "pc2ux date: %d.%d.%d\n", day, month, year);
222 	PC_DPRINTF3(1, "pc2ux time: %dh%dm%ds\n", hour, min, sec);
223 
224 	*unixtime = (int64_t)sec;
225 	*unixtime += 60 * (int64_t)min;
226 	*unixtime += 3600 * (int64_t)hour;
227 	*unixtime += 86400 * (int64_t)(day -1);
228 	while (month > 1) {
229 		month--;
230 		*unixtime += 86400 * (int64_t)days_in_month(month, year);
231 	}
232 	while (year > YEAR_ZERO) {
233 		year--;
234 		*unixtime += 86400 * (int64_t)days_in_year(year);
235 	}
236 	/*
237 	 * For FAT, the beginning of all time is 01/01/1980,
238 	 * and years are counted relative to that.
239 	 * We adjust this base value by the timezone offset
240 	 * that is passed in to pcfs at mount time.
241 	 */
242 	*unixtime += YZ_SECS;
243 	*unixtime += pc_tz.secondswest;
244 
245 	/*
246 	 * FAT epoch is past UNIX epoch - negative UNIX times
247 	 * cannot result from the conversion.
248 	 */
249 	ASSERT(*unixtime > 0);
250 	PC_DPRINTF1(1, "pc2ux unixtime: %lld\n", (long long)(*unixtime));
251 }
252 
253 /*
254  * Determine whether a character is valid for a long file name.
255  * It is easier to determine by filtering out invalid characters.
256  * Following are invalid characters in a long filename.
257  *	/ \ : * ? < > | "
258  */
259 int
260 pc_valid_lfn_char(char c)
261 {
262 	const char *cp;
263 	int n;
264 
265 	static const char invaltab[] = {
266 		"/\\:*?<>|\""
267 	};
268 
269 	cp = invaltab;
270 	n = sizeof (invaltab) - 1;
271 	while (n--) {
272 		if (c == *cp++)
273 			return (0);
274 	}
275 	return (1);
276 }
277 
278 int
279 pc_valid_long_fn(char *namep, int utf8)
280 {
281 	char *tmp;
282 	int len, error;
283 	char *prohibited[13] = {
284 		"/", "\\", ":", "*", "?", "<", ">", "|", "\"", YEN, LRO, RLO,
285 		    NULL
286 	};
287 
288 	if (utf8) {
289 		/* UTF-8 */
290 		if ((len = u8_validate(namep, strlen(namep), prohibited,
291 		    (U8_VALIDATE_ENTIRE|U8_VALIDATE_CHECK_ADDITIONAL),
292 		    &error)) < 0)
293 			return (0);
294 		if (len > PCMAXNAMLEN)
295 			return (0);
296 	} else {
297 		/* UTF-16 */
298 		for (tmp = namep; (*tmp != '\0') || (*(tmp+1) != '\0');
299 		    tmp += 2) {
300 			if ((*(tmp+1) == '\0') && !pc_valid_lfn_char(*tmp))
301 				return (0);
302 
303 			/* Prohibit the Yen character */
304 			if ((*(tmp+1) == '\0') && (*tmp == '\xa5'))
305 				return (0);
306 
307 			/* Prohibit the left-to-right override control char */
308 			if ((*(tmp+1) == '\x20') && (*tmp == '\x2d'))
309 				return (0);
310 
311 			/* Prohibit the right-to-left override control char */
312 			if ((*(tmp+1) == '\x20') && (*tmp == '\x2e'))
313 				return (0);
314 		}
315 		if ((tmp - namep) > (PCMAXNAMLEN * sizeof (uint16_t)))
316 			return (0);
317 	}
318 	return (1);
319 }
320 
321 int
322 pc_fname_ext_to_name(char *namep, char *fname, char *ext, int foldcase)
323 {
324 	int	i;
325 	char	*tp = namep;
326 	char	c;
327 
328 	i = PCFNAMESIZE;
329 	while (i-- && ((c = *fname) != ' ')) {
330 		if (!(c == '.' || pc_validchar(c))) {
331 			return (-1);
332 		}
333 		if (foldcase)
334 			*tp++ = tolower(c);
335 		else
336 			*tp++ = c;
337 		fname++;
338 	}
339 	if (*ext != ' ') {
340 		*tp++ = '.';
341 		i = PCFEXTSIZE;
342 		while (i-- && ((c = *ext) != ' ')) {
343 			if (!pc_validchar(c)) {
344 				return (-1);
345 			}
346 			if (foldcase)
347 				*tp++ = tolower(c);
348 			else
349 				*tp++ = c;
350 			ext++;
351 		}
352 	}
353 	*tp = '\0';
354 	return (0);
355 }
356