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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