1 /* $OpenBSD: parsetime.c,v 1.14 2004/06/17 22:09:11 millert Exp $ */
2
3 /*
4 * parsetime.c - parse time for at(1)
5 * Copyright (C) 1993, 1994 Thomas Koenig
6 *
7 * modifications for english-language times
8 * Copyright (C) 1993 David Parsons
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. The name of the author(s) may not be used to endorse or promote
16 * products derived from this software without specific prior written
17 * permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
31 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
32 * |NOON | |[TOMORROW] |
33 * |MIDNIGHT | |[DAY OF WEEK] |
34 * \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
35 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
36 */
37
38 #include <sys/types.h>
39 #include <errno.h>
40 #include <ctype.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <time.h>
45 #include <tzfile.h>
46 #include <unistd.h>
47
48 #include "globals.h"
49 #include "at.h"
50
51 /* Structures and unions */
52
53 enum { /* symbols */
54 MIDNIGHT, NOON, TEATIME,
55 PM, AM, TOMORROW, TODAY, NOW,
56 MINUTES, HOURS, DAYS, WEEKS,
57 NUMBER, PLUS, DOT, SLASH, ID, JUNK,
58 JAN, FEB, MAR, APR, MAY, JUN,
59 JUL, AUG, SEP, OCT, NOV, DEC,
60 SUN, MON, TUE, WED, THU, FRI, SAT
61 };
62
63 /*
64 * parse translation table - table driven parsers can be your FRIEND!
65 */
66 struct {
67 char *name; /* token name */
68 int value; /* token id */
69 int plural; /* is this plural? */
70 } Specials[] = {
71 { "midnight", MIDNIGHT, 0 }, /* 00:00:00 of today or tomorrow */
72 { "noon", NOON, 0 }, /* 12:00:00 of today or tomorrow */
73 { "teatime", TEATIME, 0 }, /* 16:00:00 of today or tomorrow */
74 { "am", AM, 0 }, /* morning times for 0-12 clock */
75 { "pm", PM, 0 }, /* evening times for 0-12 clock */
76 { "tomorrow", TOMORROW, 0 }, /* execute 24 hours from time */
77 { "today", TODAY, 0 }, /* execute today - don't advance time */
78 { "now", NOW, 0 }, /* opt prefix for PLUS */
79
80 { "minute", MINUTES, 0 }, /* minutes multiplier */
81 { "min", MINUTES, 0 },
82 { "m", MINUTES, 0 },
83 { "minutes", MINUTES, 1 }, /* (pluralized) */
84 { "hour", HOURS, 0 }, /* hours ... */
85 { "hr", HOURS, 0 }, /* abbreviated */
86 { "h", HOURS, 0 },
87 { "hours", HOURS, 1 }, /* (pluralized) */
88 { "day", DAYS, 0 }, /* days ... */
89 { "d", DAYS, 0 },
90 { "days", DAYS, 1 }, /* (pluralized) */
91 { "week", WEEKS, 0 }, /* week ... */
92 { "w", WEEKS, 0 },
93 { "weeks", WEEKS, 1 }, /* (pluralized) */
94 { "jan", JAN, 0 },
95 { "feb", FEB, 0 },
96 { "mar", MAR, 0 },
97 { "apr", APR, 0 },
98 { "may", MAY, 0 },
99 { "jun", JUN, 0 },
100 { "jul", JUL, 0 },
101 { "aug", AUG, 0 },
102 { "sep", SEP, 0 },
103 { "oct", OCT, 0 },
104 { "nov", NOV, 0 },
105 { "dec", DEC, 0 },
106 { "january", JAN,0 },
107 { "february", FEB,0 },
108 { "march", MAR,0 },
109 { "april", APR,0 },
110 { "may", MAY,0 },
111 { "june", JUN,0 },
112 { "july", JUL,0 },
113 { "august", AUG,0 },
114 { "september", SEP,0 },
115 { "october", OCT,0 },
116 { "november", NOV,0 },
117 { "december", DEC,0 },
118 { "sunday", SUN, 0 },
119 { "sun", SUN, 0 },
120 { "monday", MON, 0 },
121 { "mon", MON, 0 },
122 { "tuesday", TUE, 0 },
123 { "tue", TUE, 0 },
124 { "wednesday", WED, 0 },
125 { "wed", WED, 0 },
126 { "thursday", THU, 0 },
127 { "thu", THU, 0 },
128 { "friday", FRI, 0 },
129 { "fri", FRI, 0 },
130 { "saturday", SAT, 0 },
131 { "sat", SAT, 0 },
132 };
133
134 static char **scp; /* scanner - pointer at arglist */
135 static char scc; /* scanner - count of remaining arguments */
136 static char *sct; /* scanner - next char pointer in current argument */
137 static int need; /* scanner - need to advance to next argument */
138 static char *sc_token; /* scanner - token buffer */
139 static size_t sc_len; /* scanner - length of token buffer */
140 static int sc_tokid; /* scanner - token id */
141 static int sc_tokplur; /* scanner - is token plural? */
142
143 #ifndef lint
144 static const char rcsid[] = "$OpenBSD: parsetime.c,v 1.14 2004/06/17 22:09:11 millert Exp $";
145 #endif
146
147 /*
148 * parse a token, checking if it's something special to us
149 */
150 static int
parse_token(char * arg)151 parse_token(char *arg)
152 {
153 int i;
154
155 for (i=0; i < sizeof(Specials) / sizeof(Specials[0]); i++) {
156 if (strcasecmp(Specials[i].name, arg) == 0) {
157 sc_tokplur = Specials[i].plural;
158 return (sc_tokid = Specials[i].value);
159 }
160 }
161
162 /* not special - must be some random id */
163 return (ID);
164 }
165
166
167 /*
168 * init_scanner() sets up the scanner to eat arguments
169 */
170 static int
init_scanner(int argc,char ** argv)171 init_scanner(int argc, char **argv)
172 {
173 scp = argv;
174 scc = argc;
175 need = 1;
176 sc_len = 1;
177 while (argc-- > 0)
178 sc_len += strlen(*argv++);
179
180 if ((sc_token = (char *) malloc(sc_len)) == NULL) {
181 fprintf(stderr, "%s: Insufficient virtual memory\n",
182 ProgramName);
183 return (-1);
184 }
185 return (0);
186 }
187
188 /*
189 * token() fetches a token from the input stream
190 */
191 static int
token(void)192 token(void)
193 {
194 int idx;
195
196 for (;;) {
197 bzero(sc_token, sc_len);
198 sc_tokid = EOF;
199 sc_tokplur = 0;
200 idx = 0;
201
202 /*
203 * if we need to read another argument, walk along the
204 * argument list; when we fall off the arglist, we'll
205 * just return EOF forever
206 */
207 if (need) {
208 if (scc < 1)
209 return (sc_tokid);
210 sct = *scp;
211 scp++;
212 scc--;
213 need = 0;
214 }
215 /*
216 * eat whitespace now - if we walk off the end of the argument,
217 * we'll continue, which puts us up at the top of the while loop
218 * to fetch the next argument in
219 */
220 while (isspace(*sct))
221 ++sct;
222 if (!*sct) {
223 need = 1;
224 continue;
225 }
226
227 /*
228 * preserve the first character of the new token
229 */
230 sc_token[0] = *sct++;
231
232 /*
233 * then see what it is
234 */
235 if (isdigit(sc_token[0])) {
236 while (isdigit(*sct))
237 sc_token[++idx] = *sct++;
238 sc_token[++idx] = 0;
239 return ((sc_tokid = NUMBER));
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 = SLASH));
252 else
253 return ((sc_tokid = JUNK));
254 }
255 }
256
257
258 /*
259 * plonk() gives an appropriate error message if a token is incorrect
260 */
261 static void
plonk(int tok)262 plonk(int tok)
263 {
264 fprintf(stderr, "%s: %s time\n", ProgramName,
265 (tok == EOF) ? "incomplete" : "garbled");
266 }
267
268
269 /*
270 * expect() gets a token and returns -1 if it's not the token we want
271 */
272 static int
expect(int desired)273 expect(int desired)
274 {
275 if (token() != desired) {
276 plonk(sc_tokid);
277 return (-1);
278 }
279 return (0);
280 }
281
282
283 /*
284 * dateadd() adds a number of minutes to a date. It is extraordinarily
285 * stupid regarding day-of-month overflow, and will most likely not
286 * work properly
287 */
288 static void
dateadd(int minutes,struct tm * tm)289 dateadd(int minutes, struct tm *tm)
290 {
291 /* increment days */
292
293 while (minutes > 24*60) {
294 minutes -= 24*60;
295 tm->tm_mday++;
296 }
297
298 /* increment hours */
299 while (minutes > 60) {
300 minutes -= 60;
301 tm->tm_hour++;
302 if (tm->tm_hour > 23) {
303 tm->tm_mday++;
304 tm->tm_hour = 0;
305 }
306 }
307
308 /* increment minutes */
309 tm->tm_min += minutes;
310
311 if (tm->tm_min > 59) {
312 tm->tm_hour++;
313 tm->tm_min -= 60;
314
315 if (tm->tm_hour > 23) {
316 tm->tm_mday++;
317 tm->tm_hour = 0;
318 }
319 }
320 }
321
322
323 /*
324 * plus() parses a now + time
325 *
326 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS]
327 *
328 */
329 static int
plus(struct tm * tm)330 plus(struct tm *tm)
331 {
332 int delay;
333 int expectplur;
334
335 if (expect(NUMBER) != 0)
336 return (-1);
337
338 delay = atoi(sc_token);
339 expectplur = (delay != 1) ? 1 : 0;
340
341 switch (token()) {
342 case WEEKS:
343 delay *= 7;
344 case DAYS:
345 delay *= 24;
346 case HOURS:
347 delay *= 60;
348 case MINUTES:
349 if (expectplur != sc_tokplur)
350 fprintf(stderr, "%s: pluralization is wrong\n",
351 ProgramName);
352 dateadd(delay, tm);
353 return (0);
354 }
355
356 plonk(sc_tokid);
357 return (-1);
358 }
359
360
361 /*
362 * tod() computes the time of day
363 * [NUMBER [DOT NUMBER] [AM|PM]]
364 */
365 static int
tod(struct tm * tm)366 tod(struct tm *tm)
367 {
368 int hour, minute = 0;
369 size_t tlen;
370
371 hour = atoi(sc_token);
372 tlen = strlen(sc_token);
373
374 /*
375 * first pick out the time of day - if it's 4 digits, we assume
376 * a HHMM time, otherwise it's HH DOT MM time
377 */
378 if (token() == DOT) {
379 if (expect(NUMBER) != 0)
380 return (-1);
381 minute = atoi(sc_token);
382 if (minute > 59)
383 goto bad;
384 token();
385 } else if (tlen == 4) {
386 minute = hour % 100;
387 if (minute > 59)
388 goto bad;
389 hour = hour / 100;
390 }
391
392 /*
393 * check if an AM or PM specifier was given
394 */
395 if (sc_tokid == AM || sc_tokid == PM) {
396 if (hour > 12)
397 goto bad;
398
399 if (sc_tokid == PM) {
400 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
401 hour += 12;
402 } else {
403 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
404 hour = 0;
405 }
406 token();
407 } else if (hour > 23)
408 goto bad;
409
410 /*
411 * if we specify an absolute time, we don't want to bump the day even
412 * if we've gone past that time - but if we're specifying a time plus
413 * a relative offset, it's okay to bump things
414 */
415 if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
416 tm->tm_mday++;
417 tm->tm_wday++;
418 }
419
420 tm->tm_hour = hour;
421 tm->tm_min = minute;
422 if (tm->tm_hour == 24) {
423 tm->tm_hour = 0;
424 tm->tm_mday++;
425 }
426 return (0);
427 bad:
428 fprintf(stderr, "%s: garbled time\n", ProgramName);
429 return (-1);
430 }
431
432
433 /*
434 * assign_date() assigns a date, wrapping to next year if needed
435 */
436 static void
assign_date(struct tm * tm,int mday,int mon,int year)437 assign_date(struct tm *tm, int mday, int mon, int year)
438 {
439
440 /*
441 * Convert year into tm_year format (year - 1900).
442 * We may be given the year in 2 digit, 4 digit, or tm_year format.
443 */
444 if (year != -1) {
445 if (year >= TM_YEAR_BASE)
446 year -= TM_YEAR_BASE; /* convert from 4 digit year */
447 else if (year < 100) {
448 /* Convert to tm_year assuming current century */
449 year += (tm->tm_year / 100) * 100;
450
451 if (year == tm->tm_year - 1)
452 year++; /* Common off by one error */
453 else if (year < tm->tm_year)
454 year += 100; /* must be in next century */
455 }
456 }
457
458 if (year < 0 &&
459 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
460 year = tm->tm_year + 1;
461
462 tm->tm_mday = mday;
463 tm->tm_mon = mon;
464
465 if (year >= 0)
466 tm->tm_year = year;
467 }
468
469
470 /*
471 * month() picks apart a month specification
472 *
473 * /[<month> NUMBER [NUMBER]] \
474 * |[TOMORROW] |
475 * |[DAY OF WEEK] |
476 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
477 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
478 */
479 static int
month(struct tm * tm)480 month(struct tm *tm)
481 {
482 int year = (-1);
483 int mday, wday, mon;
484 size_t tlen;
485
486 switch (sc_tokid) {
487 case PLUS:
488 if (plus(tm) != 0)
489 return (-1);
490 break;
491
492 case TOMORROW:
493 /* do something tomorrow */
494 tm->tm_mday++;
495 tm->tm_wday++;
496 case TODAY:
497 /* force ourselves to stay in today - no further processing */
498 token();
499 break;
500
501 case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
502 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
503 /*
504 * do month mday [year]
505 */
506 mon = sc_tokid - JAN;
507 if (expect(NUMBER) != 0)
508 return (-1);
509 mday = atoi(sc_token);
510 if (token() == NUMBER) {
511 year = atoi(sc_token);
512 token();
513 }
514 assign_date(tm, mday, mon, year);
515 break;
516
517 case SUN: case MON: case TUE:
518 case WED: case THU: case FRI:
519 case SAT:
520 /* do a particular day of the week */
521 wday = sc_tokid - SUN;
522
523 mday = tm->tm_mday;
524
525 /* if this day is < today, then roll to next week */
526 if (wday < tm->tm_wday)
527 mday += 7 - (tm->tm_wday - wday);
528 else
529 mday += (wday - tm->tm_wday);
530
531 tm->tm_wday = wday;
532
533 assign_date(tm, mday, tm->tm_mon, tm->tm_year);
534 break;
535
536 case NUMBER:
537 /*
538 * get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
539 */
540 tlen = strlen(sc_token);
541 mon = atoi(sc_token);
542 token();
543
544 if (sc_tokid == SLASH || sc_tokid == DOT) {
545 int sep;
546
547 sep = sc_tokid;
548 if (expect(NUMBER) != 0)
549 return (-1);
550 mday = atoi(sc_token);
551 if (token() == sep) {
552 if (expect(NUMBER) != 0)
553 return (-1);
554 year = atoi(sc_token);
555 token();
556 }
557
558 /*
559 * flip months and days for european timing
560 */
561 if (sep == DOT) {
562 int x = mday;
563 mday = mon;
564 mon = x;
565 }
566 } else if (tlen == 6 || tlen == 8) {
567 if (tlen == 8) {
568 year = (mon % 10000) - TM_YEAR_BASE;
569 mon /= 10000;
570 } else {
571 year = mon % 100;
572 mon /= 100;
573 }
574 mday = mon % 100;
575 mon /= 100;
576 } else
577 goto bad;
578
579 mon--;
580 if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
581 goto bad;
582
583 assign_date(tm, mday, mon, year);
584 break;
585 }
586 return (0);
587 bad:
588 fprintf(stderr, "%s: garbled time\n", ProgramName);
589 return (-1);
590 }
591
592
593 time_t
parsetime(int argc,char ** argv)594 parsetime(int argc, char **argv)
595 {
596 /*
597 * Do the argument parsing, die if necessary, and return the
598 * time the job should be run.
599 */
600 time_t nowtimer, runtimer;
601 struct tm nowtime, runtime;
602 int hr = 0;
603 /* this MUST be initialized to zero for midnight/noon/teatime */
604
605 if (argc == 0)
606 return (-1);
607
608 nowtimer = time(NULL);
609 nowtime = *localtime(&nowtimer);
610
611 runtime = nowtime;
612 runtime.tm_sec = 0;
613 runtime.tm_isdst = 0;
614
615 if (init_scanner(argc, argv) == -1)
616 return (-1);
617
618 switch (token()) {
619 case NOW: /* now is optional prefix for PLUS tree */
620 token();
621 if (sc_tokid == EOF) {
622 runtime = nowtime;
623 break;
624 }
625 else if (sc_tokid != PLUS)
626 plonk(sc_tokid);
627 case PLUS:
628 if (plus(&runtime) != 0)
629 return (-1);
630 break;
631
632 case NUMBER:
633 if (tod(&runtime) != 0 || month(&runtime) != 0)
634 return (-1);
635 break;
636
637 /*
638 * evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
639 * hr to zero up above, then fall into this case in such a
640 * way so we add +12 +4 hours to it for teatime, +12 hours
641 * to it for noon, and nothing at all for midnight, then
642 * set our runtime to that hour before leaping into the
643 * month scanner
644 */
645 case TEATIME:
646 hr += 4;
647 case NOON:
648 hr += 12;
649 case MIDNIGHT:
650 if (runtime.tm_hour >= hr) {
651 runtime.tm_mday++;
652 runtime.tm_wday++;
653 }
654 runtime.tm_hour = hr;
655 runtime.tm_min = 0;
656 token();
657 /* fall through to month setting */
658 default:
659 if (month(&runtime) != 0)
660 return (-1);
661 break;
662 } /* ugly case statement */
663 if (expect(EOF) != 0)
664 return (-1);
665
666 /*
667 * adjust for daylight savings time
668 */
669 runtime.tm_isdst = -1;
670 runtimer = mktime(&runtime);
671 if (runtime.tm_isdst > 0) {
672 runtimer -= 3600;
673 runtimer = mktime(&runtime);
674 }
675
676 if (runtimer < 0) {
677 fprintf(stderr, "%s: garbled time\n", ProgramName);
678 return (-1);
679 }
680
681 if (nowtimer > runtimer) {
682 fprintf(stderr, "%s: Trying to travel back in time\n",
683 ProgramName);
684 return (-1);
685 }
686
687 return (runtimer);
688 }
689