1 /*
2 * parsetime.c - parse time for at(1)
3 * Copyright (C) 1993, 1994 Thomas Koenig
4 *
5 * modifications for English-language times
6 * Copyright (C) 1993 David Parsons
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. The name of the author(s) may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS
29 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \
30 * |NOON | |[TOMORROW] |
31 * |MIDNIGHT | |[DAY OF WEEK] |
32 * \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
33 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
34 *
35 * $FreeBSD: src/usr.bin/at/parsetime.c,v 1.27 2005/08/18 08:18:02 stefanf Exp $
36 */
37
38 /* System Headers */
39
40 #include <sys/param.h>
41 #include <ctype.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <time.h>
48 #include <unistd.h>
49
50 /* Local headers */
51
52 #include "at.h"
53 #include "panic.h"
54 #include "parsetime.h"
55
56
57 /* Structures and unions */
58
59 enum { /* symbols */
60 MIDNIGHT, NOON, TEATIME,
61 PM, AM, TOMORROW, TODAY, NOW,
62 MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
63 NUMBER, PLUS, DOT, SLASH, ID, JUNK,
64 JAN, FEB, MAR, APR, MAY, JUN,
65 JUL, AUG, SEP, OCT, NOV, DEC,
66 SUN, MON, TUE, WED, THU, FRI, SAT
67 };
68
69 /* parse translation table - table driven parsers can be your FRIEND!
70 */
71 static const struct {
72 const char *name; /* token name */
73 int value; /* token id */
74 int plural; /* is this plural? */
75 } Specials[] = {
76 { "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */
77 { "noon", NOON,0 }, /* 12:00:00 of today or tomorrow */
78 { "teatime", TEATIME,0 }, /* 16:00:00 of today or tomorrow */
79 { "am", AM,0 }, /* morning times for 0-12 clock */
80 { "pm", PM,0 }, /* evening times for 0-12 clock */
81 { "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */
82 { "today", TODAY, 0 }, /* execute today - don't advance time */
83 { "now", NOW,0 }, /* opt prefix for PLUS */
84
85 { "minute", MINUTES,0 }, /* minutes multiplier */
86 { "minutes", MINUTES,1 }, /* (pluralized) */
87 { "hour", HOURS,0 }, /* hours ... */
88 { "hours", HOURS,1 }, /* (pluralized) */
89 { "day", DAYS,0 }, /* days ... */
90 { "days", DAYS,1 }, /* (pluralized) */
91 { "week", WEEKS,0 }, /* week ... */
92 { "weeks", WEEKS,1 }, /* (pluralized) */
93 { "month", MONTHS,0 }, /* month ... */
94 { "months", MONTHS,1 }, /* (pluralized) */
95 { "year", YEARS,0 }, /* year ... */
96 { "years", YEARS,1 }, /* (pluralized) */
97 { "jan", JAN,0 },
98 { "feb", FEB,0 },
99 { "mar", MAR,0 },
100 { "apr", APR,0 },
101 { "may", MAY,0 },
102 { "jun", JUN,0 },
103 { "jul", JUL,0 },
104 { "aug", AUG,0 },
105 { "sep", SEP,0 },
106 { "oct", OCT,0 },
107 { "nov", NOV,0 },
108 { "dec", DEC,0 },
109 { "january", JAN,0 },
110 { "february", FEB,0 },
111 { "march", MAR,0 },
112 { "april", APR,0 },
113 { "may", MAY,0 },
114 { "june", JUN,0 },
115 { "july", JUL,0 },
116 { "august", AUG,0 },
117 { "september", SEP,0 },
118 { "october", OCT,0 },
119 { "november", NOV,0 },
120 { "december", DEC,0 },
121 { "sunday", SUN, 0 },
122 { "sun", SUN, 0 },
123 { "monday", MON, 0 },
124 { "mon", MON, 0 },
125 { "tuesday", TUE, 0 },
126 { "tue", TUE, 0 },
127 { "wednesday", WED, 0 },
128 { "wed", WED, 0 },
129 { "thursday", THU, 0 },
130 { "thu", THU, 0 },
131 { "friday", FRI, 0 },
132 { "fri", FRI, 0 },
133 { "saturday", SAT, 0 },
134 { "sat", SAT, 0 },
135 } ;
136
137 /* File scope variables */
138
139 static char **scp; /* scanner - pointer at arglist */
140 static char scc; /* scanner - count of remaining arguments */
141 static char *sct; /* scanner - next char pointer in current argument */
142 static int need; /* scanner - need to advance to next argument */
143
144 static char *sc_token; /* scanner - token buffer */
145 static size_t sc_len; /* scanner - length of token buffer */
146 static int sc_tokid; /* scanner - token id */
147 static int sc_tokplur; /* scanner - is token plural? */
148
149 /* Local functions */
150
151 /*
152 * parse a token, checking if it's something special to us
153 */
154 static int
parse_token(char * arg)155 parse_token(char *arg)
156 {
157 size_t i;
158
159 for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
160 if (strcasecmp(Specials[i].name, arg) == 0) {
161 sc_tokplur = Specials[i].plural;
162 return sc_tokid = Specials[i].value;
163 }
164
165 /* not special - must be some random id */
166 return ID;
167 } /* parse_token */
168
169
170 /*
171 * init_scanner() sets up the scanner to eat arguments
172 */
173 static void
init_scanner(int argc,char ** argv)174 init_scanner(int argc, char **argv)
175 {
176 scp = argv;
177 scc = argc;
178 need = 1;
179 sc_len = 1;
180 while (argc-- > 0)
181 sc_len += strlen(*argv++);
182
183 if ((sc_token = malloc(sc_len)) == NULL)
184 errx(EXIT_FAILURE, "virtual memory exhausted");
185 } /* init_scanner */
186
187 /*
188 * token() fetches a token from the input stream
189 */
190 static int
token(void)191 token(void)
192 {
193 int idx;
194
195 while (1) {
196 memset(sc_token, 0, sc_len);
197 sc_tokid = EOF;
198 sc_tokplur = 0;
199 idx = 0;
200
201 /* if we need to read another argument, walk along the argument list;
202 * when we fall off the arglist, we'll just return EOF forever
203 */
204 if (need) {
205 if (scc < 1)
206 return sc_tokid;
207 sct = *scp;
208 scp++;
209 scc--;
210 need = 0;
211 }
212 /* eat whitespace now - if we walk off the end of the argument,
213 * we'll continue, which puts us up at the top of the while loop
214 * to fetch the next argument in
215 */
216 while (isspace(*sct))
217 ++sct;
218 if (!*sct) {
219 need = 1;
220 continue;
221 }
222
223 /* preserve the first character of the new token
224 */
225 sc_token[0] = *sct++;
226
227 /* then see what it is
228 */
229 if (isdigit(sc_token[0])) {
230 while (isdigit(*sct))
231 sc_token[++idx] = *sct++;
232 sc_token[++idx] = 0;
233 return sc_tokid = NUMBER;
234 }
235 else if (isalpha(sc_token[0])) {
236 while (isalpha(*sct))
237 sc_token[++idx] = *sct++;
238 sc_token[++idx] = 0;
239 return parse_token(sc_token);
240 }
241 else if (sc_token[0] == ':' || sc_token[0] == '.')
242 return sc_tokid = DOT;
243 else if (sc_token[0] == '+')
244 return sc_tokid = PLUS;
245 else if (sc_token[0] == '/')
246 return sc_tokid = SLASH;
247 else
248 return sc_tokid = JUNK;
249 } /* while (1) */
250 } /* token */
251
252
253 /*
254 * plonk() gives an appropriate error message if a token is incorrect
255 */
256 static void
plonk(int tok)257 plonk(int tok)
258 {
259 panic((tok == EOF) ? "incomplete time"
260 : "garbled time");
261 } /* plonk */
262
263
264 /*
265 * expect() gets a token and dies most horribly if it's not the token we want
266 */
267 static void
expect(int desired)268 expect(int desired)
269 {
270 if (token() != desired)
271 plonk(sc_tokid); /* and we die here... */
272 } /* expect */
273
274
275 /*
276 * plus() parses a now + time
277 *
278 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
279 *
280 */
281
282 static void
plus(struct tm * tm)283 plus(struct tm *tm)
284 {
285 int delay;
286 int expectplur;
287
288 expect(NUMBER);
289
290 delay = atoi(sc_token);
291 expectplur = (delay != 1) ? 1 : 0;
292
293 switch (token()) {
294 case YEARS:
295 tm->tm_year += delay;
296 break;
297 case MONTHS:
298 tm->tm_mon += delay;
299 break;
300 case WEEKS:
301 delay *= 7;
302 /* FALLTHROUGH */
303 case DAYS:
304 tm->tm_mday += delay;
305 break;
306 case HOURS:
307 tm->tm_hour += delay;
308 break;
309 case MINUTES:
310 tm->tm_min += delay;
311 break;
312 default:
313 plonk(sc_tokid);
314 break;
315 }
316
317 if (expectplur != sc_tokplur)
318 warnx("pluralization is wrong");
319
320 tm->tm_isdst = -1;
321 if (mktime(tm) < 0)
322 plonk(sc_tokid);
323
324 } /* plus */
325
326
327 /*
328 * tod() computes the time of day
329 * [NUMBER [DOT NUMBER] [AM|PM]]
330 */
331 static void
tod(struct tm * tm)332 tod(struct tm *tm)
333 {
334 int hour, minute = 0;
335 int tlen;
336
337 hour = atoi(sc_token);
338 tlen = strlen(sc_token);
339
340 /* first pick out the time of day - if it's 4 digits, we assume
341 * a HHMM time, otherwise it's HH DOT MM time
342 */
343 if (token() == DOT) {
344 expect(NUMBER);
345 minute = atoi(sc_token);
346 if (minute > 59)
347 panic("garbled time");
348 token();
349 }
350 else if (tlen == 4) {
351 minute = hour%100;
352 if (minute > 59)
353 panic("garbled time");
354 hour = hour/100;
355 }
356
357 /* check if an AM or PM specifier was given
358 */
359 if (sc_tokid == AM || sc_tokid == PM) {
360 if (hour > 12)
361 panic("garbled time");
362
363 if (sc_tokid == PM) {
364 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
365 hour += 12;
366 } else {
367 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
368 hour = 0;
369 }
370 token();
371 }
372 else if (hour > 23)
373 panic("garbled time");
374
375 /* if we specify an absolute time, we don't want to bump the day even
376 * if we've gone past that time - but if we're specifying a time plus
377 * a relative offset, it's okay to bump things
378 */
379 if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
380 tm->tm_mday++;
381 tm->tm_wday++;
382 }
383
384 tm->tm_hour = hour;
385 tm->tm_min = minute;
386 if (tm->tm_hour == 24) {
387 tm->tm_hour = 0;
388 tm->tm_mday++;
389 }
390 } /* tod */
391
392
393 /*
394 * assign_date() assigns a date, wrapping to next year if needed
395 */
396 static void
assign_date(struct tm * tm,long mday,long mon,long year)397 assign_date(struct tm *tm, long mday, long mon, long year)
398 {
399
400 /*
401 * Convert year into tm_year format (year - 1900).
402 * We may be given the year in 2 digit, 4 digit, or tm_year format.
403 */
404 if (year != -1) {
405 if (year >= 1900)
406 year -= 1900; /* convert from 4 digit year */
407 else if (year < 100) {
408 /* convert from 2 digit year */
409 struct tm *lt;
410 time_t now;
411
412 time(&now);
413 lt = localtime(&now);
414
415 /* Convert to tm_year assuming current century */
416 year += rounddown(lt->tm_year, 100);
417
418 if (year == lt->tm_year - 1) year++;
419 else if (year < lt->tm_year)
420 year += 100; /* must be in next century */
421 }
422 }
423
424 if (year < 0 &&
425 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
426 year = tm->tm_year + 1;
427
428 tm->tm_mday = mday;
429 tm->tm_mon = mon;
430
431 if (year >= 0)
432 tm->tm_year = year;
433 } /* assign_date */
434
435
436 /*
437 * month() picks apart a month specification
438 *
439 * /[<month> NUMBER [NUMBER]] \
440 * |[TOMORROW] |
441 * |[DAY OF WEEK] |
442 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
443 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
444 */
445 static void
month(struct tm * tm)446 month(struct tm *tm)
447 {
448 long year= (-1);
449 long mday = 0, wday, mon;
450 int tlen;
451
452 switch (sc_tokid) {
453 case PLUS:
454 plus(tm);
455 break;
456
457 case TOMORROW:
458 /* do something tomorrow */
459 tm->tm_mday ++;
460 tm->tm_wday ++;
461 /* FALLTHROUGH */
462 case TODAY: /* force ourselves to stay in today - no further processing */
463 token();
464 break;
465
466 case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
467 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
468 /* do month mday [year]
469 */
470 mon = (sc_tokid-JAN);
471 expect(NUMBER);
472 mday = atol(sc_token);
473 if (token() == NUMBER) {
474 year = atol(sc_token);
475 token();
476 }
477 assign_date(tm, mday, mon, year);
478 break;
479
480 case SUN: case MON: case TUE:
481 case WED: case THU: case FRI:
482 case SAT:
483 /* do a particular day of the week
484 */
485 wday = (sc_tokid-SUN);
486
487 mday = tm->tm_mday;
488
489 /* if this day is < today, then roll to next week
490 */
491 if (wday < tm->tm_wday)
492 mday += 7 - (tm->tm_wday - wday);
493 else
494 mday += (wday - tm->tm_wday);
495
496 tm->tm_wday = wday;
497
498 assign_date(tm, mday, tm->tm_mon, tm->tm_year);
499 break;
500
501 case NUMBER:
502 /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
503 */
504 tlen = strlen(sc_token);
505 mon = atol(sc_token);
506 token();
507
508 if (sc_tokid == SLASH || sc_tokid == DOT) {
509 int sep;
510
511 sep = sc_tokid;
512 expect(NUMBER);
513 mday = atol(sc_token);
514 if (token() == sep) {
515 expect(NUMBER);
516 year = atol(sc_token);
517 token();
518 }
519
520 /* flip months and days for European timing
521 */
522 if (sep == DOT) {
523 int x = mday;
524 mday = mon;
525 mon = x;
526 }
527 }
528 else if (tlen == 6 || tlen == 8) {
529 if (tlen == 8) {
530 year = (mon % 10000) - 1900;
531 mon /= 10000;
532 }
533 else {
534 year = mon % 100;
535 mon /= 100;
536 }
537 mday = mon % 100;
538 mon /= 100;
539 }
540 else
541 panic("garbled time");
542
543 mon--;
544 if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
545 panic("garbled time");
546
547 assign_date(tm, mday, mon, year);
548 break;
549 } /* case */
550 } /* month */
551
552
553 /* Global functions */
554
555 time_t
parsetime(int argc,char ** argv)556 parsetime(int argc, char **argv)
557 {
558 /* Do the argument parsing, die if necessary, and return the time the job
559 * should be run.
560 */
561 time_t nowtimer, runtimer;
562 struct tm nowtime, runtime;
563 int hr = 0;
564 /* this MUST be initialized to zero for midnight/noon/teatime */
565
566 nowtimer = time(NULL);
567 nowtime = *localtime(&nowtimer);
568
569 runtime = nowtime;
570 runtime.tm_sec = 0;
571 runtime.tm_isdst = 0;
572
573 if (argc <= optind)
574 usage();
575
576 init_scanner(argc-optind, argv+optind);
577
578 switch (token()) {
579 case NOW:
580 if (scc < 1) {
581 return nowtimer;
582 }
583 /* now is optional prefix for PLUS tree */
584 expect(PLUS);
585 /* FALLTHROUGH */
586 case PLUS:
587 plus(&runtime);
588 break;
589
590 case NUMBER:
591 tod(&runtime);
592 month(&runtime);
593 break;
594
595 /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
596 * hr to zero up above, then fall into this case in such a
597 * way so we add +12 +4 hours to it for teatime, +12 hours
598 * to it for noon, and nothing at all for midnight, then
599 * set our runtime to that hour before leaping into the
600 * month scanner
601 */
602 case TEATIME:
603 hr += 4;
604 /* FALLTHROUGH */
605 case NOON:
606 hr += 12;
607 /* FALLTHROUGH */
608 case MIDNIGHT:
609 if (runtime.tm_hour >= hr) {
610 runtime.tm_mday++;
611 runtime.tm_wday++;
612 }
613 runtime.tm_hour = hr;
614 runtime.tm_min = 0;
615 token();
616 /* FALLTHROUGH */
617 default:
618 month(&runtime);
619 break;
620 } /* ugly case statement */
621 expect(EOF);
622
623 /* convert back to time_t
624 */
625 runtime.tm_isdst = -1;
626 runtimer = mktime(&runtime);
627
628 if (runtimer < 0)
629 panic("garbled time");
630
631 if (nowtimer > runtimer)
632 panic("trying to travel back in time");
633
634 return runtimer;
635 } /* parsetime */
636