1 /*
2 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3 *
4 * SPDX-License-Identifier: MPL-2.0 AND BSD-2-Clause
5 *
6 * This Source Code Form is subject to the terms of the Mozilla Public
7 * License, v. 2.0. If a copy of the MPL was not distributed with this
8 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
9 *
10 * See the COPYRIGHT file distributed with this work for additional
11 * information regarding copyright ownership.
12 */
13
14 /*-
15 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
16 * All rights reserved.
17 *
18 * This code was contributed to The NetBSD Foundation by Klaus Klein.
19 *
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
22 * are met:
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39 * POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include <ctype.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <time.h>
47
48 #include <isc/tm.h>
49 #include <isc/util.h>
50
51 /*
52 * Portable conversion routines for struct tm, replacing
53 * timegm() and strptime(), which are not available on all
54 * platforms and don't always behave the same way when they
55 * are.
56 */
57
58 /*
59 * We do not implement alternate representations. However, we always
60 * check whether a given modifier is allowed for a certain conversion.
61 */
62 #define ALT_E 0x01
63 #define ALT_O 0x02
64 #define LEGAL_ALT(x) \
65 { \
66 if ((alt_format & ~(x)) != 0) \
67 return ((0)); \
68 }
69
70 #ifndef TM_YEAR_BASE
71 #define TM_YEAR_BASE 1900
72 #endif /* ifndef TM_YEAR_BASE */
73
74 static const char *day[7] = { "Sunday", "Monday", "Tuesday", "Wednesday",
75 "Thursday", "Friday", "Saturday" };
76 static const char *abday[7] = {
77 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
78 };
79 static const char *mon[12] = {
80 "January", "February", "March", "April", "May", "June",
81 "July", "August", "September", "October", "November", "December"
82 };
83 static const char *abmon[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
84 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
85 static const char *am_pm[2] = { "AM", "PM" };
86
87 static int
conv_num(const char ** buf,int * dest,int llim,int ulim)88 conv_num(const char **buf, int *dest, int llim, int ulim) {
89 int result = 0;
90
91 /* The limit also determines the number of valid digits. */
92 int rulim = ulim;
93
94 if (!isdigit((unsigned char)**buf)) {
95 return (0);
96 }
97
98 do {
99 result *= 10;
100 result += *(*buf)++ - '0';
101 rulim /= 10;
102 } while ((result * 10 <= ulim) && rulim && **buf >= '0' &&
103 **buf <= '9');
104
105 if (result < llim || result > ulim) {
106 return (0);
107 }
108
109 *dest = result;
110 return (1);
111 }
112
113 time_t
isc_tm_timegm(struct tm * tm)114 isc_tm_timegm(struct tm *tm) {
115 time_t ret;
116 int i, yday = 0, leapday;
117 int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30 };
118
119 leapday = ((((tm->tm_year + 1900) % 4) == 0 &&
120 ((tm->tm_year + 1900) % 100) != 0) ||
121 ((tm->tm_year + 1900) % 400) == 0)
122 ? 1
123 : 0;
124 mdays[1] += leapday;
125
126 yday = tm->tm_mday - 1;
127 for (i = 1; i <= tm->tm_mon; i++) {
128 yday += mdays[i - 1];
129 }
130 ret = tm->tm_sec + (60 * tm->tm_min) + (3600 * tm->tm_hour) +
131 (86400 *
132 (yday + ((tm->tm_year - 70) * 365) + ((tm->tm_year - 69) / 4) -
133 ((tm->tm_year - 1) / 100) + ((tm->tm_year + 299) / 400)));
134 return (ret);
135 }
136
137 char *
isc_tm_strptime(const char * buf,const char * fmt,struct tm * tm)138 isc_tm_strptime(const char *buf, const char *fmt, struct tm *tm) {
139 char c, *ret;
140 const char *bp;
141 size_t len = 0;
142 int alt_format, i, split_year = 0;
143
144 REQUIRE(buf != NULL);
145 REQUIRE(fmt != NULL);
146 REQUIRE(tm != NULL);
147
148 memset(tm, 0, sizeof(struct tm));
149
150 bp = buf;
151
152 while ((c = *fmt) != '\0') {
153 /* Clear `alternate' modifier prior to new conversion. */
154 alt_format = 0;
155
156 /* Eat up white-space. */
157 if (isspace((unsigned char)c)) {
158 while (isspace((unsigned char)*bp)) {
159 bp++;
160 }
161
162 fmt++;
163 continue;
164 }
165
166 if ((c = *fmt++) != '%') {
167 goto literal;
168 }
169
170 again:
171 switch (c = *fmt++) {
172 case '%': /* "%%" is converted to "%". */
173 literal:
174 if (c != *bp++) {
175 return (0);
176 }
177 break;
178
179 /*
180 * "Alternative" modifiers. Just set the appropriate flag
181 * and start over again.
182 */
183 case 'E': /* "%E?" alternative conversion modifier. */
184 LEGAL_ALT(0);
185 alt_format |= ALT_E;
186 goto again;
187
188 case 'O': /* "%O?" alternative conversion modifier. */
189 LEGAL_ALT(0);
190 alt_format |= ALT_O;
191 goto again;
192
193 /*
194 * "Complex" conversion rules, implemented through recursion.
195 */
196 case 'c': /* Date and time, using the locale's format. */
197 LEGAL_ALT(ALT_E);
198 if (!(bp = isc_tm_strptime(bp, "%x %X", tm))) {
199 return (0);
200 }
201 break;
202
203 case 'D': /* The date as "%m/%d/%y". */
204 LEGAL_ALT(0);
205 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) {
206 return (0);
207 }
208 break;
209
210 case 'R': /* The time as "%H:%M". */
211 LEGAL_ALT(0);
212 if (!(bp = isc_tm_strptime(bp, "%H:%M", tm))) {
213 return (0);
214 }
215 break;
216
217 case 'r': /* The time in 12-hour clock representation. */
218 LEGAL_ALT(0);
219 if (!(bp = isc_tm_strptime(bp, "%I:%M:%S %p", tm))) {
220 return (0);
221 }
222 break;
223
224 case 'T': /* The time as "%H:%M:%S". */
225 LEGAL_ALT(0);
226 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) {
227 return (0);
228 }
229 break;
230
231 case 'X': /* The time, using the locale's format. */
232 LEGAL_ALT(ALT_E);
233 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) {
234 return (0);
235 }
236 break;
237
238 case 'x': /* The date, using the locale's format. */
239 LEGAL_ALT(ALT_E);
240 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) {
241 return (0);
242 }
243 break;
244
245 /*
246 * "Elementary" conversion rules.
247 */
248 case 'A': /* The day of week, using the locale's form. */
249 case 'a':
250 LEGAL_ALT(0);
251 for (i = 0; i < 7; i++) {
252 /* Full name. */
253 len = strlen(day[i]);
254 if (strncasecmp(day[i], bp, len) == 0) {
255 break;
256 }
257
258 /* Abbreviated name. */
259 len = strlen(abday[i]);
260 if (strncasecmp(abday[i], bp, len) == 0) {
261 break;
262 }
263 }
264
265 /* Nothing matched. */
266 if (i == 7) {
267 return (0);
268 }
269
270 tm->tm_wday = i;
271 bp += len;
272 break;
273
274 case 'B': /* The month, using the locale's form. */
275 case 'b':
276 case 'h':
277 LEGAL_ALT(0);
278 for (i = 0; i < 12; i++) {
279 /* Full name. */
280 len = strlen(mon[i]);
281 if (strncasecmp(mon[i], bp, len) == 0) {
282 break;
283 }
284
285 /* Abbreviated name. */
286 len = strlen(abmon[i]);
287 if (strncasecmp(abmon[i], bp, len) == 0) {
288 break;
289 }
290 }
291
292 /* Nothing matched. */
293 if (i == 12) {
294 return (0);
295 }
296
297 tm->tm_mon = i;
298 bp += len;
299 break;
300
301 case 'C': /* The century number. */
302 LEGAL_ALT(ALT_E);
303 if (!(conv_num(&bp, &i, 0, 99))) {
304 return (0);
305 }
306
307 if (split_year) {
308 tm->tm_year = (tm->tm_year % 100) + (i * 100);
309 } else {
310 tm->tm_year = i * 100;
311 split_year = 1;
312 }
313 break;
314
315 case 'd': /* The day of month. */
316 case 'e':
317 LEGAL_ALT(ALT_O);
318 if (!(conv_num(&bp, &tm->tm_mday, 1, 31))) {
319 return (0);
320 }
321 break;
322
323 case 'k': /* The hour (24-hour clock representation). */
324 LEGAL_ALT(0);
325 /* FALLTHROUGH */
326 case 'H':
327 LEGAL_ALT(ALT_O);
328 if (!(conv_num(&bp, &tm->tm_hour, 0, 23))) {
329 return (0);
330 }
331 break;
332
333 case 'l': /* The hour (12-hour clock representation). */
334 LEGAL_ALT(0);
335 /* FALLTHROUGH */
336 case 'I':
337 LEGAL_ALT(ALT_O);
338 if (!(conv_num(&bp, &tm->tm_hour, 1, 12))) {
339 return (0);
340 }
341 if (tm->tm_hour == 12) {
342 tm->tm_hour = 0;
343 }
344 break;
345
346 case 'j': /* The day of year. */
347 LEGAL_ALT(0);
348 if (!(conv_num(&bp, &i, 1, 366))) {
349 return (0);
350 }
351 tm->tm_yday = i - 1;
352 break;
353
354 case 'M': /* The minute. */
355 LEGAL_ALT(ALT_O);
356 if (!(conv_num(&bp, &tm->tm_min, 0, 59))) {
357 return (0);
358 }
359 break;
360
361 case 'm': /* The month. */
362 LEGAL_ALT(ALT_O);
363 if (!(conv_num(&bp, &i, 1, 12))) {
364 return (0);
365 }
366 tm->tm_mon = i - 1;
367 break;
368
369 case 'p': /* The locale's equivalent of AM/PM. */
370 LEGAL_ALT(0);
371 /* AM? */
372 if (strcasecmp(am_pm[0], bp) == 0) {
373 if (tm->tm_hour > 11) {
374 return (0);
375 }
376
377 bp += strlen(am_pm[0]);
378 break;
379 }
380 /* PM? */
381 else if (strcasecmp(am_pm[1], bp) == 0)
382 {
383 if (tm->tm_hour > 11) {
384 return (0);
385 }
386
387 tm->tm_hour += 12;
388 bp += strlen(am_pm[1]);
389 break;
390 }
391
392 /* Nothing matched. */
393 return (0);
394
395 case 'S': /* The seconds. */
396 LEGAL_ALT(ALT_O);
397 if (!(conv_num(&bp, &tm->tm_sec, 0, 61))) {
398 return (0);
399 }
400 break;
401
402 case 'U': /* The week of year, beginning on sunday. */
403 case 'W': /* The week of year, beginning on monday. */
404 LEGAL_ALT(ALT_O);
405 /*
406 * XXX This is bogus, as we can not assume any valid
407 * information present in the tm structure at this
408 * point to calculate a real value, so just check the
409 * range for now.
410 */
411 if (!(conv_num(&bp, &i, 0, 53))) {
412 return (0);
413 }
414 break;
415
416 case 'w': /* The day of week, beginning on sunday. */
417 LEGAL_ALT(ALT_O);
418 if (!(conv_num(&bp, &tm->tm_wday, 0, 6))) {
419 return (0);
420 }
421 break;
422
423 case 'Y': /* The year. */
424 LEGAL_ALT(ALT_E);
425 if (!(conv_num(&bp, &i, 0, 9999))) {
426 return (0);
427 }
428
429 tm->tm_year = i - TM_YEAR_BASE;
430 break;
431
432 case 'y': /* The year within 100 years of the epoch. */
433 LEGAL_ALT(ALT_E | ALT_O);
434 if (!(conv_num(&bp, &i, 0, 99))) {
435 return (0);
436 }
437
438 if (split_year) {
439 tm->tm_year = ((tm->tm_year / 100) * 100) + i;
440 break;
441 }
442 split_year = 1;
443 if (i <= 68) {
444 tm->tm_year = i + 2000 - TM_YEAR_BASE;
445 } else {
446 tm->tm_year = i + 1900 - TM_YEAR_BASE;
447 }
448 break;
449
450 /*
451 * Miscellaneous conversions.
452 */
453 case 'n': /* Any kind of white-space. */
454 case 't':
455 LEGAL_ALT(0);
456 while (isspace((unsigned char)*bp)) {
457 bp++;
458 }
459 break;
460
461 default: /* Unknown/unsupported conversion. */
462 return (0);
463 }
464 }
465
466 /* LINTED functional specification */
467 DE_CONST(bp, ret);
468 return (ret);
469 }
470