PageRenderTime 46ms CodeModel.GetById 15ms app.highlight 25ms RepoModel.GetById 1ms app.codeStats 0ms

/usr.bin/at/parsetime.c

https://bitbucket.org/freebsd/freebsd-head/
C | 670 lines | 439 code | 90 blank | 141 comment | 113 complexity | 4fd6be20a16b061b2016ee2d014049c2 MD5 | raw file
  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
 36#include <sys/cdefs.h>
 37__FBSDID("$FreeBSD$");
 38
 39/* System Headers */
 40
 41#include <sys/types.h>
 42#include <ctype.h>
 43#include <err.h>
 44#include <errno.h>
 45#include <stdio.h>
 46#include <stdlib.h>
 47#include <string.h>
 48#include <time.h>
 49#include <unistd.h>
 50#ifndef __FreeBSD__
 51#include <getopt.h>
 52#endif
 53
 54/* Local headers */
 55
 56#include "at.h"
 57#include "panic.h"
 58#include "parsetime.h"
 59
 60
 61/* Structures and unions */
 62
 63enum {	/* symbols */
 64    MIDNIGHT, NOON, TEATIME,
 65    PM, AM, TOMORROW, TODAY, NOW,
 66    MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
 67    NUMBER, PLUS, MINUS, DOT, SLASH, ID, JUNK,
 68    JAN, FEB, MAR, APR, MAY, JUN,
 69    JUL, AUG, SEP, OCT, NOV, DEC,
 70    SUN, MON, TUE, WED, THU, FRI, SAT
 71    };
 72
 73/* parse translation table - table driven parsers can be your FRIEND!
 74 */
 75static const struct {
 76    const char *name;	/* token name */
 77    int value;	/* token id */
 78    int plural;	/* is this plural? */
 79} Specials[] = {
 80    { "midnight", MIDNIGHT,0 },	/* 00:00:00 of today or tomorrow */
 81    { "noon", NOON,0 },		/* 12:00:00 of today or tomorrow */
 82    { "teatime", TEATIME,0 },	/* 16:00:00 of today or tomorrow */
 83    { "am", AM,0 },		/* morning times for 0-12 clock */
 84    { "pm", PM,0 },		/* evening times for 0-12 clock */
 85    { "tomorrow", TOMORROW,0 },	/* execute 24 hours from time */
 86    { "today", TODAY, 0 },	/* execute today - don't advance time */
 87    { "now", NOW,0 },		/* opt prefix for PLUS */
 88
 89    { "minute", MINUTES,0 },	/* minutes multiplier */
 90    { "minutes", MINUTES,1 },	/* (pluralized) */
 91    { "hour", HOURS,0 },	/* hours ... */
 92    { "hours", HOURS,1 },	/* (pluralized) */
 93    { "day", DAYS,0 },		/* days ... */
 94    { "days", DAYS,1 },		/* (pluralized) */
 95    { "week", WEEKS,0 },	/* week ... */
 96    { "weeks", WEEKS,1 },	/* (pluralized) */
 97    { "month", MONTHS,0 },	/* month ... */
 98    { "months", MONTHS,1 },	/* (pluralized) */
 99    { "year", YEARS,0 },	/* year ... */
100    { "years", YEARS,1 },	/* (pluralized) */
101    { "jan", JAN,0 },
102    { "feb", FEB,0 },
103    { "mar", MAR,0 },
104    { "apr", APR,0 },
105    { "may", MAY,0 },
106    { "jun", JUN,0 },
107    { "jul", JUL,0 },
108    { "aug", AUG,0 },
109    { "sep", SEP,0 },
110    { "oct", OCT,0 },
111    { "nov", NOV,0 },
112    { "dec", DEC,0 },
113    { "january", JAN,0 },
114    { "february", FEB,0 },
115    { "march", MAR,0 },
116    { "april", APR,0 },
117    { "may", MAY,0 },
118    { "june", JUN,0 },
119    { "july", JUL,0 },
120    { "august", AUG,0 },
121    { "september", SEP,0 },
122    { "october", OCT,0 },
123    { "november", NOV,0 },
124    { "december", DEC,0 },
125    { "sunday", SUN, 0 },
126    { "sun", SUN, 0 },
127    { "monday", MON, 0 },
128    { "mon", MON, 0 },
129    { "tuesday", TUE, 0 },
130    { "tue", TUE, 0 },
131    { "wednesday", WED, 0 },
132    { "wed", WED, 0 },
133    { "thursday", THU, 0 },
134    { "thu", THU, 0 },
135    { "friday", FRI, 0 },
136    { "fri", FRI, 0 },
137    { "saturday", SAT, 0 },
138    { "sat", SAT, 0 },
139} ;
140
141/* File scope variables */
142
143static char **scp;	/* scanner - pointer at arglist */
144static char scc;	/* scanner - count of remaining arguments */
145static char *sct;	/* scanner - next char pointer in current argument */
146static int need;	/* scanner - need to advance to next argument */
147
148static char *sc_token;	/* scanner - token buffer */
149static size_t sc_len;   /* scanner - length of token buffer */
150static int sc_tokid;	/* scanner - token id */
151static int sc_tokplur;	/* scanner - is token plural? */
152
153/* Local functions */
154
155/*
156 * parse a token, checking if it's something special to us
157 */
158static int
159parse_token(char *arg)
160{
161    size_t i;
162
163    for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
164	if (strcasecmp(Specials[i].name, arg) == 0) {
165	    sc_tokplur = Specials[i].plural;
166	    return sc_tokid = Specials[i].value;
167	}
168
169    /* not special - must be some random id */
170    return ID;
171} /* parse_token */
172
173
174/*
175 * init_scanner() sets up the scanner to eat arguments
176 */
177static void
178init_scanner(int argc, char **argv)
179{
180    scp = argv;
181    scc = argc;
182    need = 1;
183    sc_len = 1;
184    while (argc-- > 0)
185	sc_len += strlen(*argv++);
186
187    if ((sc_token = malloc(sc_len)) == NULL)
188	errx(EXIT_FAILURE, "virtual memory exhausted");
189} /* init_scanner */
190
191/*
192 * token() fetches a token from the input stream
193 */
194static int
195token(void)
196{
197    int idx;
198
199    while (1) {
200	memset(sc_token, 0, sc_len);
201	sc_tokid = EOF;
202	sc_tokplur = 0;
203	idx = 0;
204
205	/* if we need to read another argument, walk along the argument list;
206	 * when we fall off the arglist, we'll just return EOF forever
207	 */
208	if (need) {
209	    if (scc < 1)
210		return sc_tokid;
211	    sct = *scp;
212	    scp++;
213	    scc--;
214	    need = 0;
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	/* preserve the first character of the new token
228	 */
229	sc_token[0] = *sct++;
230
231	/* then see what it is
232	 */
233	if (isdigit(sc_token[0])) {
234	    while (isdigit(*sct))
235		sc_token[++idx] = *sct++;
236	    sc_token[++idx] = 0;
237	    return sc_tokid = NUMBER;
238	}
239	else if (isalpha(sc_token[0])) {
240	    while (isalpha(*sct))
241		sc_token[++idx] = *sct++;
242	    sc_token[++idx] = 0;
243	    return parse_token(sc_token);
244	}
245	else if (sc_token[0] == ':' || sc_token[0] == '.')
246	    return sc_tokid = DOT;
247	else if (sc_token[0] == '+')
248	    return sc_tokid = PLUS;
249	else if (sc_token[0] == '-')
250	    return sc_tokid = MINUS;
251	else if (sc_token[0] == '/')
252	    return sc_tokid = SLASH;
253	else
254	    return sc_tokid = JUNK;
255    } /* while (1) */
256} /* token */
257
258
259/*
260 * plonk() gives an appropriate error message if a token is incorrect
261 */
262static void
263plonk(int tok)
264{
265    panic((tok == EOF) ? "incomplete time"
266		       : "garbled time");
267} /* plonk */
268
269
270/* 
271 * expect() gets a token and dies most horribly if it's not the token we want
272 */
273static void
274expect(int desired)
275{
276    if (token() != desired)
277	plonk(sc_tokid);	/* and we die here... */
278} /* expect */
279
280
281/*
282 * plus_or_minus() holds functionality common to plus() and minus()
283 */
284static void
285plus_or_minus(struct tm *tm, int delay)
286{
287    int expectplur;
288
289    expectplur = (delay != 1 && delay != -1) ? 1 : 0;
290
291    switch (token()) {
292    case YEARS:
293	    tm->tm_year += delay;
294	    break;
295    case MONTHS:
296	    tm->tm_mon += delay;
297	    break;
298    case WEEKS:
299	    delay *= 7;
300    case DAYS:
301	    tm->tm_mday += delay;
302	    break;
303    case HOURS:
304	    tm->tm_hour += delay;
305	    break;
306    case MINUTES:
307	    tm->tm_min += delay;
308	    break;
309    default:
310    	    plonk(sc_tokid);
311	    break;
312    }
313
314    if (expectplur != sc_tokplur)
315	warnx("pluralization is wrong");
316
317    tm->tm_isdst = -1;
318    if (mktime(tm) < 0)
319	plonk(sc_tokid);
320} /* plus_or_minus */
321
322
323/*
324 * plus() parses a now + time
325 *
326 *  at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
327 *
328 */
329static void
330plus(struct tm *tm)
331{
332    int delay;
333
334    expect(NUMBER);
335
336    delay = atoi(sc_token);
337    plus_or_minus(tm, delay);
338} /* plus */
339
340
341/*
342 * minus() is like plus but can not be used with NOW
343 */
344static void
345minus(struct tm *tm)
346{
347    int delay;
348
349    expect(NUMBER);
350
351    delay = -atoi(sc_token);
352    plus_or_minus(tm, delay);
353} /* minus */
354
355
356/*
357 * tod() computes the time of day
358 *     [NUMBER [DOT NUMBER] [AM|PM]]
359 */
360static void
361tod(struct tm *tm)
362{
363    int hour, minute = 0;
364    int tlen;
365
366    hour = atoi(sc_token);
367    tlen = strlen(sc_token);
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	if (minute > 59)
376	    panic("garbled time");
377	token();
378    }
379    else if (tlen == 4) {
380	minute = hour%100;
381	if (minute > 59)
382	    panic("garbled time");
383	hour = hour/100;
384    }
385
386    /* check if an AM or PM specifier was given
387     */
388    if (sc_tokid == AM || sc_tokid == PM) {
389	if (hour > 12)
390	    panic("garbled time");
391
392	if (sc_tokid == PM) {
393	    if (hour != 12)	/* 12:xx PM is 12:xx, not 24:xx */
394			hour += 12;
395	} else {
396	    if (hour == 12)	/* 12:xx AM is 00:xx, not 12:xx */
397			hour = 0;
398	}
399	token();
400    }
401    else if (hour > 23)
402	panic("garbled time");
403
404    /* if we specify an absolute time, we don't want to bump the day even
405     * if we've gone past that time - but if we're specifying a time plus
406     * a relative offset, it's okay to bump things
407     */
408    if ((sc_tokid == EOF || sc_tokid == PLUS || sc_tokid == MINUS) && 
409	tm->tm_hour > hour) {
410	tm->tm_mday++;
411	tm->tm_wday++;
412    }
413
414    tm->tm_hour = hour;
415    tm->tm_min = minute;
416    if (tm->tm_hour == 24) {
417	tm->tm_hour = 0;
418	tm->tm_mday++;
419    }
420} /* tod */
421
422
423/*
424 * assign_date() assigns a date, wrapping to next year if needed
425 */
426static void
427assign_date(struct tm *tm, long mday, long mon, long year)
428{
429
430   /*
431    * Convert year into tm_year format (year - 1900).
432    * We may be given the year in 2 digit, 4 digit, or tm_year format.
433    */
434    if (year != -1) {
435	if (year >= 1900)
436		year -= 1900;   /* convert from 4 digit year */
437	else if (year < 100) {
438		/* convert from 2 digit year */
439		struct tm *lt;
440		time_t now;
441
442		time(&now);
443		lt = localtime(&now);
444
445		/* Convert to tm_year assuming current century */
446		year += (lt->tm_year / 100) * 100;
447
448		if (year == lt->tm_year - 1) year++;
449		else if (year < lt->tm_year)
450			year += 100;    /* must be in next century */
451	}
452    }
453
454    if (year < 0 &&
455	(tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
456	year = tm->tm_year + 1;
457
458    tm->tm_mday = mday;
459    tm->tm_mon = mon;
460
461    if (year >= 0)
462	tm->tm_year = year;
463} /* assign_date */
464
465
466/* 
467 * month() picks apart a month specification
468 *
469 *  /[<month> NUMBER [NUMBER]]           \
470 *  |[TOMORROW]                          |
471 *  |[DAY OF WEEK]                       |
472 *  |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
473 *  \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
474 */
475static void
476month(struct tm *tm)
477{
478    long year= (-1);
479    long mday = 0, wday, mon;
480    int tlen;
481
482    switch (sc_tokid) {
483    case PLUS:
484	    plus(tm);
485	    break;
486    case MINUS:
487	    minus(tm);
488	    break;
489
490    case TOMORROW:
491	    /* do something tomorrow */
492	    tm->tm_mday ++;
493	    tm->tm_wday ++;
494    case TODAY:	/* force ourselves to stay in today - no further processing */
495	    token();
496	    break;
497
498    case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
499    case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
500	    /* do month mday [year]
501	     */
502	    mon = (sc_tokid-JAN);
503	    expect(NUMBER);
504	    mday = atol(sc_token);
505	    if (token() == NUMBER) {
506		year = atol(sc_token);
507		token();
508	    }
509	    assign_date(tm, mday, mon, year);
510	    break;
511
512    case SUN: case MON: case TUE:
513    case WED: case THU: case FRI:
514    case SAT:
515	    /* do a particular day of the week
516	     */
517	    wday = (sc_tokid-SUN);
518
519	    mday = tm->tm_mday;
520
521	    /* if this day is < today, then roll to next week
522	     */
523	    if (wday < tm->tm_wday)
524		mday += 7 - (tm->tm_wday - wday);
525	    else
526		mday += (wday - tm->tm_wday);
527
528	    tm->tm_wday = wday;
529
530	    assign_date(tm, mday, tm->tm_mon, tm->tm_year);
531	    break;
532
533    case NUMBER:
534	    /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
535	     */
536	    tlen = strlen(sc_token);
537	    mon = atol(sc_token);
538	    token();
539
540	    if (sc_tokid == SLASH || sc_tokid == DOT) {
541		int sep;
542
543		sep = sc_tokid;
544		expect(NUMBER);
545		mday = atol(sc_token);
546		if (token() == sep) {
547		    expect(NUMBER);
548		    year = atol(sc_token);
549		    token();
550		}
551
552		/* flip months and days for European timing
553		 */
554		if (sep == DOT) {
555		    int x = mday;
556		    mday = mon;
557		    mon = x;
558		}
559	    }
560	    else if (tlen == 6 || tlen == 8) {
561		if (tlen == 8) {
562		    year = (mon % 10000) - 1900;
563		    mon /= 10000;
564		}
565		else {
566		    year = mon % 100;
567		    mon /= 100;
568		}
569		mday = mon % 100;
570		mon /= 100;
571	    }
572	    else
573		panic("garbled time");
574
575	    mon--;
576	    if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
577		panic("garbled time");
578
579	    assign_date(tm, mday, mon, year);
580	    break;
581    } /* case */
582} /* month */
583
584
585/* Global functions */
586
587time_t
588parsetime(int argc, char **argv)
589{
590/* Do the argument parsing, die if necessary, and return the time the job
591 * should be run.
592 */
593    time_t nowtimer, runtimer;
594    struct tm nowtime, runtime;
595    int hr = 0;
596    /* this MUST be initialized to zero for midnight/noon/teatime */
597
598    nowtimer = time(NULL);
599    nowtime = *localtime(&nowtimer);
600
601    runtime = nowtime;
602    runtime.tm_sec = 0;
603    runtime.tm_isdst = 0;
604
605    if (argc <= optind)
606	usage();
607
608    init_scanner(argc-optind, argv+optind);
609
610    switch (token()) {
611    case NOW:	
612	    if (scc < 1) {
613		return nowtimer;
614	    }
615	    /* now is optional prefix for PLUS tree */
616	    expect(PLUS);
617    case PLUS:
618	    plus(&runtime);
619	    break;
620
621	    /* MINUS is different from PLUS in that NOW is not
622	     * an optional prefix for it
623	     */
624    case MINUS:
625	    minus(&runtime);
626	    break;
627    case NUMBER:
628	    tod(&runtime);
629	    month(&runtime);
630	    break;
631
632	    /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
633	     * hr to zero up above, then fall into this case in such a
634	     * way so we add +12 +4 hours to it for teatime, +12 hours
635	     * to it for noon, and nothing at all for midnight, then
636	     * set our runtime to that hour before leaping into the
637	     * month scanner
638	     */
639    case TEATIME:
640	    hr += 4;
641    case NOON:
642	    hr += 12;
643    case MIDNIGHT:
644	    if (runtime.tm_hour >= hr) {
645		runtime.tm_mday++;
646		runtime.tm_wday++;
647	    }
648	    runtime.tm_hour = hr;
649	    runtime.tm_min = 0;
650	    token();
651	    /* FALLTHROUGH to month setting */
652    default:
653	    month(&runtime);
654	    break;
655    } /* ugly case statement */
656    expect(EOF);
657
658    /* convert back to time_t
659     */
660    runtime.tm_isdst = -1;
661    runtimer = mktime(&runtime);
662
663    if (runtimer < 0)
664	panic("garbled time");
665
666    if (nowtimer > runtimer)
667	panic("trying to travel back in time");
668
669    return runtimer;
670} /* parsetime */