1 /*-
2 * parsetime.c - parse time for at(1)
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (C) 1993, 1994 Thomas Koenig
7 *
8 * modifications for English-language times
9 * Copyright (C) 1993 David Parsons
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. The name of the author(s) may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
32 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
33 * |NOON | |[TOMORROW] |
34 * |MIDNIGHT | |[DAY OF WEEK] |
35 * \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
36 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
37 */
38
39 #include <sys/cdefs.h>
40 /* System Headers */
41
42 #include <sys/types.h>
43 #include <ctype.h>
44 #include <err.h>
45 #include <errno.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <time.h>
50 #include <unistd.h>
51 #ifndef __FreeBSD__
52 #include <getopt.h>
53 #endif
54
55 /* Local headers */
56
57 #include "at.h"
58 #include "panic.h"
59 #include "parsetime.h"
60
61
62 /* Structures and unions */
63
64 enum { /* symbols */
65 MIDNIGHT, NOON, TEATIME,
66 PM, AM, TOMORROW, TODAY, NOW,
67 MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
68 NUMBER, PLUS, MINUS, DOT, SLASH, ID, JUNK,
69 JAN, FEB, MAR, APR, MAY, JUN,
70 JUL, AUG, SEP, OCT, NOV, DEC,
71 SUN, MON, TUE, WED, THU, FRI, SAT
72 };
73
74 /* parse translation table - table driven parsers can be your FRIEND!
75 */
76 static const struct {
77 const char *name; /* token name */
78 int value; /* token id */
79 int plural; /* is this plural? */
80 } Specials[] = {
81 { "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */
82 { "noon", NOON,0 }, /* 12:00:00 of today or tomorrow */
83 { "teatime", TEATIME,0 }, /* 16:00:00 of today or tomorrow */
84 { "am", AM,0 }, /* morning times for 0-12 clock */
85 { "pm", PM,0 }, /* evening times for 0-12 clock */
86 { "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */
87 { "today", TODAY, 0 }, /* execute today - don't advance time */
88 { "now", NOW,0 }, /* opt prefix for PLUS */
89
90 { "minute", MINUTES,0 }, /* minutes multiplier */
91 { "minutes", MINUTES,1 }, /* (pluralized) */
92 { "hour", HOURS,0 }, /* hours ... */
93 { "hours", HOURS,1 }, /* (pluralized) */
94 { "day", DAYS,0 }, /* days ... */
95 { "days", DAYS,1 }, /* (pluralized) */
96 { "week", WEEKS,0 }, /* week ... */
97 { "weeks", WEEKS,1 }, /* (pluralized) */
98 { "month", MONTHS,0 }, /* month ... */
99 { "months", MONTHS,1 }, /* (pluralized) */
100 { "year", YEARS,0 }, /* year ... */
101 { "years", YEARS,1 }, /* (pluralized) */
102 { "jan", JAN,0 },
103 { "feb", FEB,0 },
104 { "mar", MAR,0 },
105 { "apr", APR,0 },
106 { "may", MAY,0 },
107 { "jun", JUN,0 },
108 { "jul", JUL,0 },
109 { "aug", AUG,0 },
110 { "sep", SEP,0 },
111 { "oct", OCT,0 },
112 { "nov", NOV,0 },
113 { "dec", DEC,0 },
114 { "january", JAN,0 },
115 { "february", FEB,0 },
116 { "march", MAR,0 },
117 { "april", APR,0 },
118 { "may", MAY,0 },
119 { "june", JUN,0 },
120 { "july", JUL,0 },
121 { "august", AUG,0 },
122 { "september", SEP,0 },
123 { "october", OCT,0 },
124 { "november", NOV,0 },
125 { "december", DEC,0 },
126 { "sunday", SUN, 0 },
127 { "sun", SUN, 0 },
128 { "monday", MON, 0 },
129 { "mon", MON, 0 },
130 { "tuesday", TUE, 0 },
131 { "tue", TUE, 0 },
132 { "wednesday", WED, 0 },
133 { "wed", WED, 0 },
134 { "thursday", THU, 0 },
135 { "thu", THU, 0 },
136 { "friday", FRI, 0 },
137 { "fri", FRI, 0 },
138 { "saturday", SAT, 0 },
139 { "sat", SAT, 0 },
140 } ;
141
142 /* File scope variables */
143
144 static char **scp; /* scanner - pointer at arglist */
145 static char scc; /* scanner - count of remaining arguments */
146 static char *sct; /* scanner - next char pointer in current argument */
147 static int need; /* scanner - need to advance to next argument */
148
149 static char *sc_token; /* scanner - token buffer */
150 static size_t sc_len; /* scanner - length of token buffer */
151 static int sc_tokid; /* scanner - token id */
152 static int sc_tokplur; /* scanner - is token plural? */
153
154 /* Local functions */
155
156 /*
157 * parse a token, checking if it's something special to us
158 */
159 static int
parse_token(char * arg)160 parse_token(char *arg)
161 {
162 size_t i;
163
164 for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
165 if (strcasecmp(Specials[i].name, arg) == 0) {
166 sc_tokplur = Specials[i].plural;
167 return sc_tokid = Specials[i].value;
168 }
169
170 /* not special - must be some random id */
171 return ID;
172 } /* parse_token */
173
174
175 /*
176 * init_scanner() sets up the scanner to eat arguments
177 */
178 static void
init_scanner(int argc,char ** argv)179 init_scanner(int argc, char **argv)
180 {
181 scp = argv;
182 scc = argc;
183 need = 1;
184 sc_len = 1;
185 while (argc-- > 0)
186 sc_len += strlen(*argv++);
187
188 if ((sc_token = malloc(sc_len)) == NULL)
189 errx(EXIT_FAILURE, "virtual memory exhausted");
190 } /* init_scanner */
191
192 /*
193 * token() fetches a token from the input stream
194 */
195 static int
token(void)196 token(void)
197 {
198 int idx;
199
200 while (1) {
201 memset(sc_token, 0, sc_len);
202 sc_tokid = EOF;
203 sc_tokplur = 0;
204 idx = 0;
205
206 /* if we need to read another argument, walk along the argument list;
207 * when we fall off the arglist, we'll just return EOF forever
208 */
209 if (need) {
210 if (scc < 1)
211 return sc_tokid;
212 sct = *scp;
213 scp++;
214 scc--;
215 need = 0;
216 }
217 /* eat whitespace now - if we walk off the end of the argument,
218 * we'll continue, which puts us up at the top of the while loop
219 * to fetch the next argument in
220 */
221 while (isspace(*sct))
222 ++sct;
223 if (!*sct) {
224 need = 1;
225 continue;
226 }
227
228 /* preserve the first character of the new token
229 */
230 sc_token[0] = *sct++;
231
232 /* then see what it is
233 */
234 if (isdigit(sc_token[0])) {
235 while (isdigit(*sct))
236 sc_token[++idx] = *sct++;
237 sc_token[++idx] = 0;
238 return sc_tokid = NUMBER;
239 }
240 else if (isalpha(sc_token[0])) {
241 while (isalpha(*sct))
242 sc_token[++idx] = *sct++;
243 sc_token[++idx] = 0;
244 return parse_token(sc_token);
245 }
246 else if (sc_token[0] == ':' || sc_token[0] == '.')
247 return sc_tokid = DOT;
248 else if (sc_token[0] == '+')
249 return sc_tokid = PLUS;
250 else if (sc_token[0] == '-')
251 return sc_tokid = MINUS;
252 else if (sc_token[0] == '/')
253 return sc_tokid = SLASH;
254 else
255 return sc_tokid = JUNK;
256 } /* while (1) */
257 } /* token */
258
259
260 /*
261 * plonk() gives an appropriate error message if a token is incorrect
262 */
263 static void
plonk(int tok)264 plonk(int tok)
265 {
266 panic((tok == EOF) ? "incomplete time"
267 : "garbled time");
268 } /* plonk */
269
270
271 /*
272 * expect() gets a token and dies most horribly if it's not the token we want
273 */
274 static void
expect(int desired)275 expect(int desired)
276 {
277 if (token() != desired)
278 plonk(sc_tokid); /* and we die here... */
279 } /* expect */
280
281
282 /*
283 * plus_or_minus() holds functionality common to plus() and minus()
284 */
285 static void
plus_or_minus(struct tm * tm,int delay)286 plus_or_minus(struct tm *tm, int delay)
287 {
288 int expectplur;
289
290 expectplur = (delay != 1 && delay != -1) ? 1 : 0;
291
292 switch (token()) {
293 case YEARS:
294 tm->tm_year += delay;
295 break;
296 case MONTHS:
297 tm->tm_mon += delay;
298 break;
299 case WEEKS:
300 delay *= 7;
301 case DAYS:
302 tm->tm_mday += delay;
303 break;
304 case HOURS:
305 tm->tm_hour += delay;
306 break;
307 case MINUTES:
308 tm->tm_min += delay;
309 break;
310 default:
311 plonk(sc_tokid);
312 break;
313 }
314
315 if (expectplur != sc_tokplur)
316 warnx("pluralization is wrong");
317
318 tm->tm_isdst = -1;
319 if (mktime(tm) < 0)
320 plonk(sc_tokid);
321 } /* plus_or_minus */
322
323
324 /*
325 * plus() parses a now + time
326 *
327 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
328 *
329 */
330 static void
plus(struct tm * tm)331 plus(struct tm *tm)
332 {
333 int delay;
334
335 expect(NUMBER);
336
337 delay = atoi(sc_token);
338 plus_or_minus(tm, delay);
339 } /* plus */
340
341
342 /*
343 * minus() is like plus but can not be used with NOW
344 */
345 static void
minus(struct tm * tm)346 minus(struct tm *tm)
347 {
348 int delay;
349
350 expect(NUMBER);
351
352 delay = -atoi(sc_token);
353 plus_or_minus(tm, delay);
354 } /* minus */
355
356
357 /*
358 * tod() computes the time of day
359 * [NUMBER [DOT NUMBER] [AM|PM]]
360 */
361 static void
tod(struct tm * tm)362 tod(struct tm *tm)
363 {
364 int hour, minute = 0;
365 int tlen;
366
367 hour = atoi(sc_token);
368 tlen = strlen(sc_token);
369
370 /* first pick out the time of day - if it's 4 digits, we assume
371 * a HHMM time, otherwise it's HH DOT MM time
372 */
373 if (token() == DOT) {
374 expect(NUMBER);
375 minute = atoi(sc_token);
376 if (minute > 59)
377 panic("garbled time");
378 token();
379 }
380 else if (tlen == 4) {
381 minute = hour%100;
382 if (minute > 59)
383 panic("garbled time");
384 hour = hour/100;
385 }
386
387 /* check if an AM or PM specifier was given
388 */
389 if (sc_tokid == AM || sc_tokid == PM) {
390 if (hour > 12)
391 panic("garbled time");
392
393 if (sc_tokid == PM) {
394 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
395 hour += 12;
396 } else {
397 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
398 hour = 0;
399 }
400 token();
401 }
402 else if (hour > 23)
403 panic("garbled time");
404
405 /* if we specify an absolute time, we don't want to bump the day even
406 * if we've gone past that time - but if we're specifying a time plus
407 * a relative offset, it's okay to bump things
408 */
409 if ((sc_tokid == EOF || sc_tokid == PLUS || sc_tokid == MINUS) &&
410 tm->tm_hour > hour) {
411 tm->tm_mday++;
412 tm->tm_wday++;
413 }
414
415 tm->tm_hour = hour;
416 tm->tm_min = minute;
417 if (tm->tm_hour == 24) {
418 tm->tm_hour = 0;
419 tm->tm_mday++;
420 }
421 } /* tod */
422
423
424 /*
425 * assign_date() assigns a date, wrapping to next year if needed
426 */
427 static void
assign_date(struct tm * tm,long mday,long mon,long year)428 assign_date(struct tm *tm, long mday, long mon, long year)
429 {
430
431 /*
432 * Convert year into tm_year format (year - 1900).
433 * We may be given the year in 2 digit, 4 digit, or tm_year format.
434 */
435 if (year != -1) {
436 if (year >= 1900)
437 year -= 1900; /* convert from 4 digit year */
438 else if (year < 100) {
439 /* convert from 2 digit year */
440 struct tm *lt;
441 time_t now;
442
443 time(&now);
444 lt = localtime(&now);
445
446 /* Convert to tm_year assuming current century */
447 year += (lt->tm_year / 100) * 100;
448
449 if (year == lt->tm_year - 1) year++;
450 else if (year < lt->tm_year)
451 year += 100; /* must be in next century */
452 }
453 }
454
455 if (year < 0 &&
456 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
457 year = tm->tm_year + 1;
458
459 tm->tm_mday = mday;
460 tm->tm_mon = mon;
461
462 if (year >= 0)
463 tm->tm_year = year;
464 } /* assign_date */
465
466
467 /*
468 * month() picks apart a month specification
469 *
470 * /[<month> NUMBER [NUMBER]] \
471 * |[TOMORROW] |
472 * |[DAY OF WEEK] |
473 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
474 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
475 */
476 static void
month(struct tm * tm)477 month(struct tm *tm)
478 {
479 long year= (-1);
480 long mday = 0, wday, mon;
481 int tlen;
482
483 switch (sc_tokid) {
484 case PLUS:
485 plus(tm);
486 break;
487 case MINUS:
488 minus(tm);
489 break;
490
491 case TOMORROW:
492 /* do something tomorrow */
493 tm->tm_mday ++;
494 tm->tm_wday ++;
495 case TODAY: /* force ourselves to stay in today - no further processing */
496 token();
497 break;
498
499 case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
500 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
501 /* do month mday [year]
502 */
503 mon = (sc_tokid-JAN);
504 expect(NUMBER);
505 mday = atol(sc_token);
506 if (token() == NUMBER) {
507 year = atol(sc_token);
508 token();
509 }
510 assign_date(tm, mday, mon, year);
511 break;
512
513 case SUN: case MON: case TUE:
514 case WED: case THU: case FRI:
515 case SAT:
516 /* do a particular day of the week
517 */
518 wday = (sc_tokid-SUN);
519
520 mday = tm->tm_mday;
521
522 /* if this day is < today, then roll to next week
523 */
524 if (wday < tm->tm_wday)
525 mday += 7 - (tm->tm_wday - wday);
526 else
527 mday += (wday - tm->tm_wday);
528
529 tm->tm_wday = wday;
530
531 assign_date(tm, mday, tm->tm_mon, tm->tm_year);
532 break;
533
534 case NUMBER:
535 /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
536 */
537 tlen = strlen(sc_token);
538 mon = atol(sc_token);
539 token();
540
541 if (sc_tokid == SLASH || sc_tokid == DOT) {
542 int sep;
543
544 sep = sc_tokid;
545 expect(NUMBER);
546 mday = atol(sc_token);
547 if (token() == sep) {
548 expect(NUMBER);
549 year = atol(sc_token);
550 token();
551 }
552
553 /* flip months and days for European timing
554 */
555 if (sep == DOT) {
556 int x = mday;
557 mday = mon;
558 mon = x;
559 }
560 }
561 else if (tlen == 6 || tlen == 8) {
562 if (tlen == 8) {
563 year = (mon % 10000) - 1900;
564 mon /= 10000;
565 }
566 else {
567 year = mon % 100;
568 mon /= 100;
569 }
570 mday = mon % 100;
571 mon /= 100;
572 }
573 else
574 panic("garbled time");
575
576 mon--;
577 if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
578 panic("garbled time");
579
580 assign_date(tm, mday, mon, year);
581 break;
582 } /* case */
583 } /* month */
584
585
586 /* Global functions */
587
588 time_t
parsetime(int argc,char ** argv)589 parsetime(int argc, char **argv)
590 {
591 /* Do the argument parsing, die if necessary, and return the time the job
592 * should be run.
593 */
594 time_t nowtimer, runtimer;
595 struct tm nowtime, runtime;
596 int hr = 0;
597 /* this MUST be initialized to zero for midnight/noon/teatime */
598
599 nowtimer = time(NULL);
600 nowtime = *localtime(&nowtimer);
601
602 runtime = nowtime;
603 runtime.tm_sec = 0;
604 runtime.tm_isdst = 0;
605
606 if (argc <= optind)
607 usage();
608
609 init_scanner(argc-optind, argv+optind);
610
611 switch (token()) {
612 case NOW:
613 if (scc < 1) {
614 return nowtimer;
615 }
616 /* now is optional prefix for PLUS tree */
617 expect(PLUS);
618 /* FALLTHROUGH */
619 case PLUS:
620 plus(&runtime);
621 break;
622
623 /* MINUS is different from PLUS in that NOW is not
624 * an optional prefix for it
625 */
626 case MINUS:
627 minus(&runtime);
628 break;
629 case NUMBER:
630 tod(&runtime);
631 month(&runtime);
632 break;
633
634 /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
635 * hr to zero up above, then fall into this case in such a
636 * way so we add +12 +4 hours to it for teatime, +12 hours
637 * to it for noon, and nothing at all for midnight, then
638 * set our runtime to that hour before leaping into the
639 * month scanner
640 */
641 case TEATIME:
642 hr += 4;
643 /* FALLTHROUGH */
644 case NOON:
645 hr += 12;
646 /* FALLTHROUGH */
647 case MIDNIGHT:
648 if (runtime.tm_hour >= hr) {
649 runtime.tm_mday++;
650 runtime.tm_wday++;
651 }
652 runtime.tm_hour = hr;
653 runtime.tm_min = 0;
654 token();
655 /* FALLTHROUGH to month setting */
656 default:
657 month(&runtime);
658 break;
659 } /* ugly case statement */
660 expect(EOF);
661
662 /* convert back to time_t
663 */
664 runtime.tm_isdst = -1;
665 runtimer = mktime(&runtime);
666
667 if (runtimer < 0)
668 panic("garbled time");
669
670 if (nowtimer > runtimer)
671 panic("trying to travel back in time");
672
673 return runtimer;
674 } /* parsetime */
675