1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include <err.h>
31 #include <time.h>
32 #include <stdint.h>
33 #include <string.h>
34 #include <stdlib.h>
35 #include "vary.h"
36
37 struct trans {
38 int64_t val;
39 const char *str;
40 };
41
42 static struct trans trans_mon[] = {
43 { 1, "january" }, { 2, "february" }, { 3, "march" }, { 4, "april" },
44 { 5, "may"}, { 6, "june" }, { 7, "july" }, { 8, "august" },
45 { 9, "september" }, { 10, "october" }, { 11, "november" }, { 12, "december" },
46 { -1, NULL }
47 };
48
49 static struct trans trans_wday[] = {
50 { 0, "sunday" }, { 1, "monday" }, { 2, "tuesday" }, { 3, "wednesday" },
51 { 4, "thursday" }, { 5, "friday" }, { 6, "saturday" },
52 { -1, NULL }
53 };
54
55 static char digits[] = "0123456789";
56 static int adjhour(struct tm *, char, int64_t, int);
57
58 static int
domktime(struct tm * t,char type)59 domktime(struct tm *t, char type)
60 {
61 time_t ret;
62
63 while ((ret = mktime(t)) == -1 && t->tm_year > 68 && t->tm_year < 138)
64 /* While mktime() fails, adjust by an hour */
65 adjhour(t, type == '-' ? type : '+', 1, 0);
66
67 return ret;
68 }
69
70 static int
trans(const struct trans t[],const char * arg)71 trans(const struct trans t[], const char *arg)
72 {
73 int f;
74
75 for (f = 0; t[f].val != -1; f++)
76 if (!strncasecmp(t[f].str, arg, 3) ||
77 !strncasecmp(t[f].str, arg, strlen(t[f].str)))
78 return t[f].val;
79
80 return -1;
81 }
82
83 struct vary *
vary_append(struct vary * v,char * arg)84 vary_append(struct vary *v, char *arg)
85 {
86 struct vary *result, **nextp;
87
88 if (v) {
89 result = v;
90 while (v->next)
91 v = v->next;
92 nextp = &v->next;
93 } else
94 nextp = &result;
95
96 if ((*nextp = (struct vary *)malloc(sizeof(struct vary))) == NULL)
97 err(1, "malloc");
98 (*nextp)->arg = arg;
99 (*nextp)->next = NULL;
100 return result;
101 }
102
103 static int mdays[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
104
105 static int
daysinmonth(const struct tm * t)106 daysinmonth(const struct tm *t)
107 {
108 int year;
109
110 year = t->tm_year + 1900;
111
112 if (t->tm_mon == 1)
113 if (!(year % 400))
114 return 29;
115 else if (!(year % 100))
116 return 28;
117 else if (!(year % 4))
118 return 29;
119 else
120 return 28;
121 else if (t->tm_mon >= 0 && t->tm_mon < 12)
122 return mdays[t->tm_mon];
123
124 return 0;
125 }
126
127
128 static int
adjyear(struct tm * t,char type,int64_t val,int mk)129 adjyear(struct tm *t, char type, int64_t val, int mk)
130 {
131 switch (type) {
132 case '+':
133 t->tm_year += val;
134 break;
135 case '-':
136 t->tm_year -= val;
137 break;
138 default:
139 t->tm_year = val;
140 if (t->tm_year < 69)
141 t->tm_year += 100; /* as per date.c */
142 else if (t->tm_year > 1900)
143 t->tm_year -= 1900; /* struct tm holds years since 1900 */
144 break;
145 }
146 return !mk || domktime(t, type) != -1;
147 }
148
149 static int
adjmon(struct tm * t,char type,int64_t val,int istext,int mk)150 adjmon(struct tm *t, char type, int64_t val, int istext, int mk)
151 {
152 int lmdays;
153
154 if (val < 0)
155 return 0;
156
157 switch (type) {
158 case '+':
159 if (istext) {
160 if (val <= t->tm_mon)
161 val += 11 - t->tm_mon; /* early next year */
162 else
163 val -= t->tm_mon + 1; /* later this year */
164 }
165 if (val) {
166 if (!adjyear(t, '+', (t->tm_mon + val) / 12, 0))
167 return 0;
168 val %= 12;
169 t->tm_mon += val;
170 if (t->tm_mon > 11)
171 t->tm_mon -= 12;
172 }
173 break;
174
175 case '-':
176 if (istext) {
177 if (val-1 > t->tm_mon)
178 val = 13 - val + t->tm_mon; /* later last year */
179 else
180 val = t->tm_mon - val + 1; /* early this year */
181 }
182 if (val) {
183 if (!adjyear(t, '-', val / 12, 0))
184 return 0;
185 val %= 12;
186 if (val > t->tm_mon) {
187 if (!adjyear(t, '-', 1, 0))
188 return 0;
189 val -= 12;
190 }
191 t->tm_mon -= val;
192 }
193 break;
194
195 default:
196 if (val > 12 || val < 1)
197 return 0;
198 t->tm_mon = --val;
199 }
200
201 /* e.g., -v-1m on March, 31 is the last day of February in common sense */
202 lmdays = daysinmonth(t);
203 if (t->tm_mday > lmdays)
204 t->tm_mday = lmdays;
205
206 return !mk || domktime(t, type) != -1;
207 }
208
209 static int
adjday(struct tm * t,char type,int64_t val,int mk)210 adjday(struct tm *t, char type, int64_t val, int mk)
211 {
212 int lmdays;
213
214 switch (type) {
215 case '+':
216 while (val) {
217 lmdays = daysinmonth(t);
218 if (val > lmdays - t->tm_mday) {
219 val -= lmdays - t->tm_mday + 1;
220 t->tm_mday = 1;
221 if (!adjmon(t, '+', 1, 0, 0))
222 return 0;
223 } else {
224 t->tm_mday += val;
225 val = 0;
226 }
227 }
228 break;
229 case '-':
230 while (val)
231 if (val >= t->tm_mday) {
232 val -= t->tm_mday;
233 t->tm_mday = 1;
234 if (!adjmon(t, '-', 1, 0, 0))
235 return 0;
236 t->tm_mday = daysinmonth(t);
237 } else {
238 t->tm_mday -= val;
239 val = 0;
240 }
241 break;
242 default:
243 if (val > 0 && val <= daysinmonth(t))
244 t->tm_mday = val;
245 else
246 return 0;
247 break;
248 }
249
250 return !mk || domktime(t, type) != -1;
251 }
252
253 static int
adjwday(struct tm * t,char type,int64_t val,int istext,int mk)254 adjwday(struct tm *t, char type, int64_t val, int istext, int mk)
255 {
256 if (val < 0)
257 return 0;
258
259 switch (type) {
260 case '+':
261 if (istext)
262 if (val < t->tm_wday)
263 val = 7 - t->tm_wday + val; /* early next week */
264 else
265 val -= t->tm_wday; /* later this week */
266 else
267 val *= 7; /* "-v+5w" == "5 weeks in the future" */
268 return !val || adjday(t, '+', val, mk);
269 case '-':
270 if (istext) {
271 if (val > t->tm_wday)
272 val = 7 - val + t->tm_wday; /* later last week */
273 else
274 val = t->tm_wday - val; /* early this week */
275 } else
276 val *= 7; /* "-v-5w" == "5 weeks ago" */
277 return !val || adjday(t, '-', val, mk);
278 default:
279 if (val < t->tm_wday)
280 return adjday(t, '-', t->tm_wday - val, mk);
281 else if (val > 6)
282 return 0;
283 else if (val > t->tm_wday)
284 return adjday(t, '+', val - t->tm_wday, mk);
285 }
286 return 1;
287 }
288
289 static int
adjhour(struct tm * t,char type,int64_t val,int mk)290 adjhour(struct tm *t, char type, int64_t val, int mk)
291 {
292 if (val < 0)
293 return 0;
294
295 switch (type) {
296 case '+':
297 if (val) {
298 int days;
299
300 days = (t->tm_hour + val) / 24;
301 val %= 24;
302 t->tm_hour += val;
303 t->tm_hour %= 24;
304 if (!adjday(t, '+', days, 0))
305 return 0;
306 }
307 break;
308
309 case '-':
310 if (val) {
311 int days;
312
313 days = val / 24;
314 val %= 24;
315 if (val > t->tm_hour) {
316 days++;
317 val -= 24;
318 }
319 t->tm_hour -= val;
320 if (!adjday(t, '-', days, 0))
321 return 0;
322 }
323 break;
324
325 default:
326 if (val > 23)
327 return 0;
328 t->tm_hour = val;
329 }
330
331 return !mk || domktime(t, type) != -1;
332 }
333
334 static int
adjmin(struct tm * t,char type,int64_t val,int mk)335 adjmin(struct tm *t, char type, int64_t val, int mk)
336 {
337 if (val < 0)
338 return 0;
339
340 switch (type) {
341 case '+':
342 if (val) {
343 if (!adjhour(t, '+', (t->tm_min + val) / 60, 0))
344 return 0;
345 val %= 60;
346 t->tm_min += val;
347 if (t->tm_min > 59)
348 t->tm_min -= 60;
349 }
350 break;
351
352 case '-':
353 if (val) {
354 if (!adjhour(t, '-', val / 60, 0))
355 return 0;
356 val %= 60;
357 if (val > t->tm_min) {
358 if (!adjhour(t, '-', 1, 0))
359 return 0;
360 val -= 60;
361 }
362 t->tm_min -= val;
363 }
364 break;
365
366 default:
367 if (val > 59)
368 return 0;
369 t->tm_min = val;
370 }
371
372 return !mk || domktime(t, type) != -1;
373 }
374
375 static int
adjsec(struct tm * t,char type,int64_t val,int mk)376 adjsec(struct tm *t, char type, int64_t val, int mk)
377 {
378 if (val < 0)
379 return 0;
380
381 switch (type) {
382 case '+':
383 if (val) {
384 if (!adjmin(t, '+', (t->tm_sec + val) / 60, 0))
385 return 0;
386 val %= 60;
387 t->tm_sec += val;
388 if (t->tm_sec > 59)
389 t->tm_sec -= 60;
390 }
391 break;
392
393 case '-':
394 if (val) {
395 if (!adjmin(t, '-', val / 60, 0))
396 return 0;
397 val %= 60;
398 if (val > t->tm_sec) {
399 if (!adjmin(t, '-', 1, 0))
400 return 0;
401 val -= 60;
402 }
403 t->tm_sec -= val;
404 }
405 break;
406
407 default:
408 if (val > 59)
409 return 0;
410 t->tm_sec = val;
411 }
412
413 return !mk || domktime(t, type) != -1;
414 }
415
416 const struct vary *
vary_apply(const struct vary * v,struct tm * t)417 vary_apply(const struct vary *v, struct tm *t)
418 {
419 char type;
420 char which;
421 char *arg;
422 size_t len;
423 int64_t val;
424
425 for (; v; v = v->next) {
426 type = *v->arg;
427 arg = v->arg;
428 if (type == '+' || type == '-')
429 arg++;
430 else
431 type = '\0';
432 len = strlen(arg);
433 if (len < 2)
434 return v;
435
436 if (type == '\0')
437 t->tm_isdst = -1;
438
439 if (strspn(arg, digits) != len-1) {
440 val = trans(trans_wday, arg);
441 if (val != -1) {
442 if (!adjwday(t, type, val, 1, 1))
443 return v;
444 } else {
445 val = trans(trans_mon, arg);
446 if (val != -1) {
447 if (!adjmon(t, type, val, 1, 1))
448 return v;
449 } else
450 return v;
451 }
452 } else {
453 val = atoi(arg);
454 which = arg[len-1];
455
456 switch (which) {
457 case 'S':
458 if (!adjsec(t, type, val, 1))
459 return v;
460 break;
461 case 'M':
462 if (!adjmin(t, type, val, 1))
463 return v;
464 break;
465 case 'H':
466 if (!adjhour(t, type, val, 1))
467 return v;
468 break;
469 case 'd':
470 t->tm_isdst = -1;
471 if (!adjday(t, type, val, 1))
472 return v;
473 break;
474 case 'w':
475 t->tm_isdst = -1;
476 if (!adjwday(t, type, val, 0, 1))
477 return v;
478 break;
479 case 'm':
480 t->tm_isdst = -1;
481 if (!adjmon(t, type, val, 0, 1))
482 return v;
483 break;
484 case 'y':
485 t->tm_isdst = -1;
486 if (!adjyear(t, type, val, 1))
487 return v;
488 break;
489 default:
490 return v;
491 }
492 }
493 }
494 return 0;
495 }
496
497 void
vary_destroy(struct vary * v)498 vary_destroy(struct vary *v)
499 {
500 struct vary *n;
501
502 while (v) {
503 n = v->next;
504 free(v);
505 v = n;
506 }
507 }
508