parsetime.c revision 1.18 1 /* $NetBSD: parsetime.c,v 1.18 2008/04/05 16:26:57 christos 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 /* System Headers */
39
40 #include <sys/types.h>
41 #include <err.h>
42 #include <ctype.h>
43 #include <errno.h>
44 #include <stdbool.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <time.h>
49 #include <tzfile.h>
50 #include <unistd.h>
51
52 /* Local headers */
53
54 #include "at.h"
55 #include "panic.h"
56 #include "parsetime.h"
57 #include "stime.h"
58
59 /* Structures and unions */
60
61 typedef enum { /* symbols */
62 MIDNIGHT, NOON, TEATIME,
63 PM, AM, TOMORROW, TODAY, NOW,
64 MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
65 NUMBER, PLUS, DOT, SLASH, ID, JUNK,
66 JAN, FEB, MAR, APR, MAY, JUN,
67 JUL, AUG, SEP, OCT, NOV, DEC,
68 SUN, MON, TUE, WED, THU, FRI, SAT
69 } tokid_t;
70
71 /*
72 * parse translation table - table driven parsers can be your FRIEND!
73 */
74 static const struct {
75 const char *name; /* token name */
76 tokid_t value; /* token id */
77 bool plural; /* is this plural? */
78 } Specials[] = {
79 {"midnight", MIDNIGHT, false}, /* 00:00:00 of today or tomorrow */
80 {"noon", NOON, false}, /* 12:00:00 of today or tomorrow */
81 {"teatime", TEATIME, false}, /* 16:00:00 of today or tomorrow */
82 {"am", AM, false}, /* morning times for 0-12 clock */
83 {"pm", PM, false}, /* evening times for 0-12 clock */
84 {"tomorrow", TOMORROW, false}, /* execute 24 hours from time */
85 {"today", TODAY, false}, /* execute today - don't advance time */
86 {"now", NOW, false}, /* opt prefix for PLUS */
87
88 {"minute", MINUTES, false}, /* minutes multiplier */
89 {"min", MINUTES, false},
90 {"m", MINUTES, false},
91 {"minutes", MINUTES, true}, /* (pluralized) */
92 {"hour", HOURS, false}, /* hours ... */
93 {"hr", HOURS, false}, /* abbreviated */
94 {"h", HOURS, false},
95 {"hours", HOURS, true}, /* (pluralized) */
96 {"day", DAYS, false}, /* days ... */
97 {"d", DAYS, false},
98 {"days", DAYS, true}, /* (pluralized) */
99 {"week", WEEKS, false}, /* week ... */
100 {"w", WEEKS, false},
101 {"weeks", WEEKS, true}, /* (pluralized) */
102 { "month", MONTHS, 0 }, /* month ... */
103 { "months", MONTHS, 1 }, /* (pluralized) */
104 { "year", YEARS, 0 }, /* year ... */
105 { "years", YEARS, 1 }, /* (pluralized) */
106 {"jan", JAN, false},
107 {"feb", FEB, false},
108 {"mar", MAR, false},
109 {"apr", APR, false},
110 {"may", MAY, false},
111 {"jun", JUN, false},
112 {"jul", JUL, false},
113 {"aug", AUG, false},
114 {"sep", SEP, false},
115 {"oct", OCT, false},
116 {"nov", NOV, false},
117 {"dec", DEC, false},
118 {"january", JAN, false},
119 {"february", FEB, false},
120 {"march", MAR, false},
121 {"april", APR, false},
122 {"may", MAY, false},
123 {"june", JUN, false},
124 {"july", JUL, false},
125 {"august", AUG, false},
126 {"september", SEP, false},
127 {"october", OCT, false},
128 {"november", NOV, false},
129 {"december", DEC, false},
130 {"sunday", SUN, false},
131 {"sun", SUN, false},
132 {"monday", MON, false},
133 {"mon", MON, false},
134 {"tuesday", TUE, false},
135 {"tue", TUE, false},
136 {"wednesday", WED, false},
137 {"wed", WED, false},
138 {"thursday", THU, false},
139 {"thu", THU, false},
140 {"friday", FRI, false},
141 {"fri", FRI, false},
142 {"saturday", SAT, false},
143 {"sat", SAT, false}
144 };
145
146 /* File scope variables */
147
148 static char **scp; /* scanner - pointer at arglist */
149 static char scc; /* scanner - count of remaining arguments */
150 static char *sct; /* scanner - next char pointer in current argument */
151 static bool need; /* scanner - need to advance to next argument */
152
153 static char *sc_token; /* scanner - token buffer */
154 static size_t sc_len; /* scanner - length of token buffer */
155 static tokid_t sc_tokid;/* scanner - token id */
156 static bool sc_tokplur; /* scanner - is token plural? */
157
158 #ifndef lint
159 #if 0
160 static char rcsid[] = "$OpenBSD: parsetime.c,v 1.4 1997/03/01 23:40:10 millert Exp $";
161 #else
162 __RCSID("$NetBSD: parsetime.c,v 1.18 2008/04/05 16:26:57 christos Exp $");
163 #endif
164 #endif
165
166 /* Local functions */
167 static void assign_date(struct tm *, int, int, int);
168 static void expect(tokid_t);
169 static void init_scanner(int, char **);
170 static void month(struct tm *);
171 static tokid_t parse_token(char *);
172 static void plonk(int) __dead;
173 static void plus(struct tm *);
174 static void tod(struct tm *);
175 static tokid_t token(void);
176
177 /*
178 * parse a token, checking if it's something special to us
179 */
180 static tokid_t
181 parse_token(char *arg)
182 {
183 int i;
184
185 for (i=0; i < __arraycount(Specials); i++) {
186 if (strcasecmp(Specials[i].name, arg) == 0) {
187 sc_tokplur = Specials[i].plural;
188 return sc_tokid = Specials[i].value;
189 }
190 }
191
192 /* not special - must be some random id */
193 return ID;
194 }
195
196 /*
197 * init_scanner() sets up the scanner to eat arguments
198 */
199 static void
200 init_scanner(int argc, char **argv)
201 {
202
203 scp = argv;
204 scc = argc;
205 need = true;
206 sc_len = 1;
207 while (argc-- > 0)
208 sc_len += strlen(*argv++);
209
210 if ((sc_token = malloc(sc_len)) == NULL)
211 panic("Insufficient virtual memory");
212 }
213
214 /*
215 * token() fetches a token from the input stream
216 */
217 static tokid_t
218 token(void)
219 {
220 int idx;
221
222 for(;;) {
223 (void)memset(sc_token, 0, sc_len);
224 sc_tokid = EOF;
225 sc_tokplur = false;
226 idx = 0;
227
228 /*
229 * if we need to read another argument, walk along the
230 * argument list; when we fall off the arglist, we'll
231 * just return EOF forever
232 */
233 if (need) {
234 if (scc < 1)
235 return sc_tokid;
236 sct = *scp;
237 scp++;
238 scc--;
239 need = false;
240 }
241 /*
242 * eat whitespace now - if we walk off the end of the argument,
243 * we'll continue, which puts us up at the top of the while loop
244 * to fetch the next argument in
245 */
246 while (isspace((unsigned char)*sct))
247 ++sct;
248 if (!*sct) {
249 need = true;
250 continue;
251 }
252
253 /*
254 * preserve the first character of the new token
255 */
256 sc_token[0] = *sct++;
257
258 /*
259 * then see what it is
260 */
261 if (isdigit((unsigned char)sc_token[0])) {
262 while (isdigit((unsigned char)*sct))
263 sc_token[++idx] = *sct++;
264 sc_token[++idx] = 0;
265 return sc_tokid = NUMBER;
266 } else if (isalpha((unsigned char)sc_token[0])) {
267 while (isalpha((unsigned char)*sct))
268 sc_token[++idx] = *sct++;
269 sc_token[++idx] = 0;
270 return parse_token(sc_token);
271 }
272 else if (sc_token[0] == ':' || sc_token[0] == '.')
273 return sc_tokid = DOT;
274 else if (sc_token[0] == '+')
275 return sc_tokid = PLUS;
276 else if (sc_token[0] == '/')
277 return sc_tokid = SLASH;
278 else
279 return sc_tokid = JUNK;
280 }
281 }
282
283 /*
284 * plonk() gives an appropriate error message if a token is incorrect
285 */
286 __dead
287 static void
288 plonk(int tok)
289 {
290
291 panic(tok == EOF ? "incomplete time" : "garbled time");
292 }
293
294 /*
295 * expect() gets a token and dies most horribly if it's not the token we want
296 */
297 static void
298 expect(tokid_t desired)
299 {
300
301 if (token() != desired)
302 plonk(sc_tokid); /* and we die here... */
303 }
304
305 /*
306 * plus() parses a now + time
307 *
308 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
309 *
310 */
311 static void
312 plus(struct tm *tm)
313 {
314 int delay;
315 int expectplur;
316
317 expect(NUMBER);
318
319 delay = atoi(sc_token);
320 expectplur = delay != 1;
321
322 switch (token()) {
323 case YEARS:
324 tm->tm_year += delay;
325 break;
326 case MONTHS:
327 tm->tm_mon += delay;
328 break;
329 case WEEKS:
330 delay *= 7;
331 /*FALLTHROUGH*/
332 case DAYS:
333 tm->tm_mday += delay;
334 break;
335 case HOURS:
336 tm->tm_hour += delay;
337 break;
338 case MINUTES:
339 tm->tm_min += delay;
340 break;
341 default:
342 plonk(sc_tokid);
343 break;
344 }
345
346 if (expectplur != sc_tokplur)
347 warnx("pluralization is wrong");
348
349 tm->tm_isdst = -1;
350 if (mktime(tm) == -1)
351 plonk(sc_tokid);
352 }
353
354 /*
355 * tod() computes the time of day
356 * [NUMBER [DOT NUMBER] [AM|PM]]
357 */
358 static void
359 tod(struct tm *tm)
360 {
361 int hour, minute;
362 size_t tlen;
363
364 minute = 0;
365 hour = atoi(sc_token);
366 tlen = strlen(sc_token);
367
368 /*
369 * first pick out the time of day - if it's 4 digits, we assume
370 * a HHMM time, otherwise it's HH DOT MM time
371 */
372 if (token() == DOT) {
373 expect(NUMBER);
374 minute = atoi(sc_token);
375 (void)token();
376 } else if (tlen == 4) {
377 minute = hour % 100;
378 hour = hour / 100;
379 }
380
381 if (minute > 59)
382 panic("garbled time");
383
384 /*
385 * check if an AM or PM specifier was given
386 */
387 if (sc_tokid == AM || sc_tokid == PM) {
388 if (hour > 12)
389 panic("garbled time");
390
391 if (sc_tokid == PM) {
392 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
393 hour += 12;
394 } else {
395 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
396 hour = 0;
397 }
398 (void)token();
399 } else if (hour > 23)
400 panic("garbled time");
401
402 /*
403 * if we specify an absolute time, we don't want to bump the day even
404 * if we've gone past that time - but if we're specifying a time plus
405 * a relative offset, it's okay to bump things
406 */
407 if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
408 tm->tm_mday++;
409 tm->tm_wday++;
410 }
411
412 tm->tm_hour = hour;
413 tm->tm_min = minute;
414 }
415
416 /*
417 * assign_date() assigns a date, wrapping to next year if needed.
418 * Accept years in 4-digit, 2-digit, or current year (-1).
419 */
420 static void
421 assign_date(struct tm *tm, int mday, int mon, int year)
422 {
423
424 if (year > 99) { /* four digit year */
425 if (year >= TM_YEAR_BASE)
426 tm->tm_year = year - TM_YEAR_BASE;
427 else
428 panic("garbled time");
429 }
430 else if (year >= 0) { /* two digit year */
431 tm->tm_year = conv_2dig_year(year) - TM_YEAR_BASE;
432 }
433 else if (year == -1) { /* year not given (use default in tm) */
434 /* allow for 1 year range from current date */
435 if (tm->tm_mon > mon ||
436 (tm->tm_mon == mon && tm->tm_mday > mday))
437 tm->tm_year++;
438 }
439 else
440 panic("invalid year");
441
442 tm->tm_mday = mday;
443 tm->tm_mon = mon;
444 }
445
446 /*
447 * month() picks apart a month specification
448 *
449 * /[<month> NUMBER [NUMBER]] \
450 * |[TOMORROW] |
451 * |[DAY OF WEEK] |
452 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
453 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
454 */
455 static void
456 month(struct tm *tm)
457 {
458 int year;
459 int mday, wday, mon;
460 size_t tlen;
461
462 year = -1;
463 mday = 0;
464 switch (sc_tokid) {
465 case PLUS:
466 plus(tm);
467 break;
468
469 case TOMORROW:
470 /* do something tomorrow */
471 tm->tm_mday++;
472 tm->tm_wday++;
473 /*FALLTHROUGH*/
474 case TODAY:
475 /* force ourselves to stay in today - no further processing */
476 (void)token();
477 break;
478
479 case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
480 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
481 /*
482 * do month mday [year]
483 */
484 mon = sc_tokid - JAN;
485 expect(NUMBER);
486 mday = atoi(sc_token);
487 if (token() == NUMBER) {
488 year = atoi(sc_token);
489 (void)token();
490 }
491 assign_date(tm, mday, mon, year);
492 break;
493
494 case SUN: case MON: case TUE:
495 case WED: case THU: case FRI:
496 case SAT:
497 /* do a particular day of the week */
498 wday = sc_tokid - SUN;
499
500 mday = tm->tm_mday;
501
502 /* if this day is < today, then roll to next week */
503 if (wday < tm->tm_wday)
504 mday += 7 - (tm->tm_wday - wday);
505 else
506 mday += (wday - tm->tm_wday);
507
508 tm->tm_wday = wday;
509
510 assign_date(tm, mday, tm->tm_mon, tm->tm_year + TM_YEAR_BASE);
511 break;
512
513 case NUMBER:
514 /*
515 * get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
516 */
517 tlen = strlen(sc_token);
518 mon = atoi(sc_token);
519 (void)token();
520
521 if (sc_tokid == SLASH || sc_tokid == DOT) {
522 int sep;
523
524 sep = sc_tokid;
525 expect(NUMBER);
526 mday = atoi(sc_token);
527 if (token() == sep) {
528 expect(NUMBER);
529 year = atoi(sc_token);
530 (void)token();
531 }
532
533 /*
534 * flip months and days for european timing
535 */
536 if (sep == DOT) {
537 int x = mday;
538 mday = mon;
539 mon = x;
540 }
541 } else if (tlen == 6 || tlen == 8) {
542 if (tlen == 8) {
543 year = (mon % 10000) - 1900;
544 mon /= 10000;
545 } else {
546 year = mon % 100;
547 mon /= 100;
548 }
549 mday = mon % 100;
550 mon /= 100;
551 } else
552 panic("garbled time");
553
554 mon--;
555 if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
556 panic("garbled time");
557
558 assign_date(tm, mday, mon, year);
559 break;
560 default:
561 /* plonk(sc_tokid); */ /* XXX - die here? */
562 break;
563 }
564 }
565
566
567 /* Global functions */
568
569 time_t
570 parsetime(int argc, char **argv)
571 {
572 /*
573 * Do the argument parsing, die if necessary, and return the
574 * time the job should be run.
575 */
576 time_t nowtimer, runtimer;
577 struct tm nowtime, runtime;
578 int hr = 0; /* this MUST be initialized to zero for
579 midnight/noon/teatime */
580
581 nowtimer = time(NULL);
582 nowtime = *localtime(&nowtimer);
583
584 runtime = nowtime;
585 runtime.tm_sec = 0;
586
587 if (argc <= optind)
588 usage();
589
590 init_scanner(argc - optind, argv + optind);
591
592 switch (token()) {
593 case NOW:
594 if (scc < 1)
595 return nowtimer;
596
597 /* now is optional prefix for PLUS tree */
598 expect(PLUS);
599 /*FALLTHROUGH*/
600 case PLUS:
601 plus(&runtime);
602 break;
603
604 case NUMBER:
605 tod(&runtime);
606 month(&runtime);
607 break;
608
609 /*
610 * evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
611 * hr to zero up above, then fall into this case in such a
612 * way so we add +12 +4 hours to it for teatime, +12 hours
613 * to it for noon, and nothing at all for midnight, then
614 * set our runtime to that hour before leaping into the
615 * month scanner
616 */
617 case TEATIME:
618 hr += 4;
619 /*FALLTHROUGH*/
620 case NOON:
621 hr += 12;
622 /*FALLTHROUGH*/
623 case MIDNIGHT:
624 if (runtime.tm_hour >= hr) {
625 runtime.tm_mday++;
626 runtime.tm_wday++;
627 }
628 runtime.tm_hour = hr;
629 runtime.tm_min = 0;
630 (void)token();
631 /*FALLTHROUGH*/ /* fall through to month setting */
632 default:
633 month(&runtime);
634 break;
635 }
636 expect(EOF);
637
638 /*
639 * adjust for daylight savings time
640 */
641 runtime.tm_isdst = -1;
642 runtimer = mktime(&runtime);
643
644 if (runtimer == (time_t)-1)
645 panic("Invalid time");
646
647 if (nowtimer > runtimer)
648 panic("Trying to travel back in time");
649
650 return runtimer;
651 }
652