parsetime.c revision 26872 
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/* System Headers */
37
38
39#include <sys/types.h>
40#include <err.h>
41#include <errno.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <time.h>
46#include <unistd.h>
47#include <ctype.h>
48#ifndef __FreeBSD__
49#include <getopt.h>
50#endif
51
52/* Local headers */
53
54#include "at.h"
55#include "panic.h"
56
57
58/* Structures and unions */
59
60enum {	/* symbols */
61    MIDNIGHT, NOON, TEATIME,
62    PM, AM, TOMORROW, TODAY, NOW,
63    MINUTES, HOURS, DAYS, WEEKS,
64    NUMBER, PLUS, DOT, SLASH, ID, JUNK,
65    JAN, FEB, MAR, APR, MAY, JUN,
66    JUL, AUG, SEP, OCT, NOV, DEC,
67    SUN, MON, TUE, WED, THU, FRI, SAT
68    };
69
70/* parse translation table - table driven parsers can be your FRIEND!
71 */
72struct {
73    char *name;	/* token name */
74    int value;	/* token id */
75    int plural;	/* is this plural? */
76} Specials[] = {
77    { "midnight", MIDNIGHT,0 },	/* 00:00:00 of today or tomorrow */
78    { "noon", NOON,0 },		/* 12:00:00 of today or tomorrow */
79    { "teatime", TEATIME,0 },	/* 16:00:00 of today or tomorrow */
80    { "am", AM,0 },		/* morning times for 0-12 clock */
81    { "pm", PM,0 },		/* evening times for 0-12 clock */
82    { "tomorrow", TOMORROW,0 },	/* execute 24 hours from time */
83    { "today", TODAY, 0 },	/* execute today - don't advance time */
84    { "now", NOW,0 },		/* opt prefix for PLUS */
85
86    { "minute", MINUTES,0 },	/* minutes multiplier */
87    { "minutes", MINUTES,1 },	/* (pluralized) */
88    { "hour", HOURS,0 },	/* hours ... */
89    { "hours", HOURS,1 },	/* (pluralized) */
90    { "day", DAYS,0 },		/* days ... */
91    { "days", DAYS,1 },		/* (pluralized) */
92    { "week", WEEKS,0 },	/* week ... */
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    { "sunday", SUN, 0 },
107    { "sun", SUN, 0 },
108    { "monday", MON, 0 },
109    { "mon", MON, 0 },
110    { "tuesday", TUE, 0 },
111    { "tue", TUE, 0 },
112    { "wednesday", WED, 0 },
113    { "wed", WED, 0 },
114    { "thursday", THU, 0 },
115    { "thu", THU, 0 },
116    { "friday", FRI, 0 },
117    { "fri", FRI, 0 },
118    { "saturday", SAT, 0 },
119    { "sat", SAT, 0 },
120} ;
121
122/* File scope variables */
123
124static char **scp;	/* scanner - pointer at arglist */
125static char scc;	/* scanner - count of remaining arguments */
126static char *sct;	/* scanner - next char pointer in current argument */
127static int need;	/* scanner - need to advance to next argument */
128
129static char *sc_token;	/* scanner - token buffer */
130static size_t sc_len;   /* scanner - lenght of token buffer */
131static int sc_tokid;	/* scanner - token id */
132static int sc_tokplur;	/* scanner - is token plural? */
133
134static char rcsid[] = "$Id: parsetime.c,v 1.10 1997/06/23 06:44:18 charnier Exp $";
135
136/* Local functions */
137
138/*
139 * parse a token, checking if it's something special to us
140 */
141static int
142parse_token(char *arg)
143{
144    int i;
145
146    for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
147	if (strcasecmp(Specials[i].name, arg) == 0) {
148	    sc_tokplur = Specials[i].plural;
149	    return sc_tokid = Specials[i].value;
150	}
151
152    /* not special - must be some random id */
153    return ID;
154} /* parse_token */
155
156
157/*
158 * init_scanner() sets up the scanner to eat arguments
159 */
160static void
161init_scanner(int argc, char **argv)
162{
163    scp = argv;
164    scc = argc;
165    need = 1;
166    sc_len = 1;
167    while (argc-- > 0)
168	sc_len += strlen(*argv++);
169
170    sc_token = (char *) mymalloc(sc_len);
171} /* init_scanner */
172
173/*
174 * token() fetches a token from the input stream
175 */
176static int
177token()
178{
179    int idx;
180
181    while (1) {
182	memset(sc_token, 0, sc_len);
183	sc_tokid = EOF;
184	sc_tokplur = 0;
185	idx = 0;
186
187	/* if we need to read another argument, walk along the argument list;
188	 * when we fall off the arglist, we'll just return EOF forever
189	 */
190	if (need) {
191	    if (scc < 1)
192		return sc_tokid;
193	    sct = *scp;
194	    scp++;
195	    scc--;
196	    need = 0;
197	}
198	/* eat whitespace now - if we walk off the end of the argument,
199	 * we'll continue, which puts us up at the top of the while loop
200	 * to fetch the next argument in
201	 */
202	while (isspace(*sct))
203	    ++sct;
204	if (!*sct) {
205	    need = 1;
206	    continue;
207	}
208
209	/* preserve the first character of the new token
210	 */
211	sc_token[0] = *sct++;
212
213	/* then see what it is
214	 */
215	if (isdigit(sc_token[0])) {
216	    while (isdigit(*sct))
217		sc_token[++idx] = *sct++;
218	    sc_token[++idx] = 0;
219	    return sc_tokid = NUMBER;
220	}
221	else if (isalpha(sc_token[0])) {
222	    while (isalpha(*sct))
223		sc_token[++idx] = *sct++;
224	    sc_token[++idx] = 0;
225	    return parse_token(sc_token);
226	}
227	else if (sc_token[0] == ':' || sc_token[0] == '.')
228	    return sc_tokid = DOT;
229	else if (sc_token[0] == '+')
230	    return sc_tokid = PLUS;
231	else if (sc_token[0] == '/')
232	    return sc_tokid = SLASH;
233	else
234	    return sc_tokid = JUNK;
235    } /* while (1) */
236} /* token */
237
238
239/*
240 * plonk() gives an appropriate error message if a token is incorrect
241 */
242static void
243plonk(int tok)
244{
245    panic((tok == EOF) ? "incomplete time"
246		       : "garbled time");
247} /* plonk */
248
249
250/*
251 * expect() gets a token and dies most horribly if it's not the token we want
252 */
253static void
254expect(int desired)
255{
256    if (token() != desired)
257	plonk(sc_tokid);	/* and we die here... */
258} /* expect */
259
260
261/*
262 * dateadd() adds a number of minutes to a date.  It is extraordinarily
263 * stupid regarding day-of-month overflow, and will most likely not
264 * work properly
265 */
266static void
267dateadd(int minutes, struct tm *tm)
268{
269    /* increment days */
270
271    while (minutes > 24*60) {
272	minutes -= 24*60;
273	tm->tm_mday++;
274    }
275
276    /* increment hours */
277    while (minutes > 60) {
278	minutes -= 60;
279	tm->tm_hour++;
280	if (tm->tm_hour > 23) {
281	    tm->tm_mday++;
282	    tm->tm_hour = 0;
283	}
284    }
285
286    /* increment minutes */
287    tm->tm_min += minutes;
288
289    if (tm->tm_min > 59) {
290	tm->tm_hour++;
291	tm->tm_min -= 60;
292
293	if (tm->tm_hour > 23) {
294	    tm->tm_mday++;
295	    tm->tm_hour = 0;
296	}
297    }
298} /* dateadd */
299
300
301/*
302 * plus() parses a now + time
303 *
304 *  at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS]
305 *
306 */
307static void
308plus(struct tm *tm)
309{
310    int delay;
311    int expectplur;
312
313    expect(NUMBER);
314
315    delay = atoi(sc_token);
316    expectplur = (delay != 1) ? 1 : 0;
317
318    switch (token()) {
319    case WEEKS:
320	    delay *= 7;
321    case DAYS:
322	    delay *= 24;
323    case HOURS:
324	    delay *= 60;
325    case MINUTES:
326	    if (expectplur != sc_tokplur)
327		warnx("pluralization is wrong");
328	    dateadd(delay, tm);
329	    return;
330    }
331    plonk(sc_tokid);
332} /* plus */
333
334
335/*
336 * tod() computes the time of day
337 *     [NUMBER [DOT NUMBER] [AM|PM]]
338 */
339static void
340tod(struct tm *tm)
341{
342    int hour, minute = 0;
343    int tlen;
344
345    hour = atoi(sc_token);
346    tlen = strlen(sc_token);
347
348    /* first pick out the time of day - if it's 4 digits, we assume
349     * a HHMM time, otherwise it's HH DOT MM time
350     */
351    if (token() == DOT) {
352	expect(NUMBER);
353	minute = atoi(sc_token);
354	if (minute > 59)
355	    panic("garbled time");
356	token();
357    }
358    else if (tlen == 4) {
359	minute = hour%100;
360	if (minute > 59)
361	    panic("garbeld time");
362	hour = hour/100;
363    }
364
365    /* check if an AM or PM specifier was given
366     */
367    if (sc_tokid == AM || sc_tokid == PM) {
368	if (hour > 12)
369	    panic("garbled time");
370
371	if (sc_tokid == PM) {
372	    if (hour != 12)	/* 12:xx PM is 12:xx, not 24:xx */
373			hour += 12;
374	} else {
375	    if (hour == 12)	/* 12:xx AM is 00:xx, not 12:xx */
376			hour = 0;
377	}
378	token();
379    }
380    else if (hour > 23)
381	panic("garbled time");
382
383    /* if we specify an absolute time, we don't want to bump the day even
384     * if we've gone past that time - but if we're specifying a time plus
385     * a relative offset, it's okay to bump things
386     */
387    if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
388	tm->tm_mday++;
389	tm->tm_wday++;
390    }
391
392    tm->tm_hour = hour;
393    tm->tm_min = minute;
394    if (tm->tm_hour == 24) {
395	tm->tm_hour = 0;
396	tm->tm_mday++;
397    }
398} /* tod */
399
400
401/*
402 * assign_date() assigns a date, wrapping to next year if needed
403 */
404static void
405assign_date(struct tm *tm, long mday, long mon, long year)
406{
407    if (year > 99) {
408	if (year > 1899)
409	    year -= 1900;
410	else
411	    panic("garbled time");
412    }
413
414    if (year < 0 &&
415	(tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
416	year = tm->tm_year + 1;
417
418    tm->tm_mday = mday;
419    tm->tm_mon = mon;
420
421    if (year >= 0)
422	tm->tm_year = year;
423} /* assign_date */
424
425
426/*
427 * month() picks apart a month specification
428 *
429 *  /[<month> NUMBER [NUMBER]]           \
430 *  |[TOMORROW]                          |
431 *  |[DAY OF WEEK]                       |
432 *  |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
433 *  \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
434 */
435static void
436month(struct tm *tm)
437{
438    long year= (-1);
439    long mday, wday, mon;
440    int tlen;
441
442    switch (sc_tokid) {
443    case PLUS:
444	    plus(tm);
445	    break;
446
447    case TOMORROW:
448	    /* do something tomorrow */
449	    tm->tm_mday ++;
450	    tm->tm_wday ++;
451    case TODAY:	/* force ourselves to stay in today - no further processing */
452	    token();
453	    break;
454
455    case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
456    case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
457	    /* do month mday [year]
458	     */
459	    mon = (sc_tokid-JAN);
460	    expect(NUMBER);
461	    mday = atol(sc_token);
462	    if (token() == NUMBER) {
463		year = atol(sc_token);
464		token();
465	    }
466	    assign_date(tm, mday, mon, year);
467	    break;
468
469    case SUN: case MON: case TUE:
470    case WED: case THU: case FRI:
471    case SAT:
472	    /* do a particular day of the week
473	     */
474	    wday = (sc_tokid-SUN);
475
476	    mday = tm->tm_mday;
477
478	    /* if this day is < today, then roll to next week
479	     */
480	    if (wday < tm->tm_wday)
481		mday += 7 - (tm->tm_wday - wday);
482	    else
483		mday += (wday - tm->tm_wday);
484
485	    tm->tm_wday = wday;
486
487	    assign_date(tm, mday, tm->tm_mon, tm->tm_year);
488	    break;
489
490    case NUMBER:
491	    /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
492	     */
493	    tlen = strlen(sc_token);
494	    mon = atol(sc_token);
495	    token();
496
497	    if (sc_tokid == SLASH || sc_tokid == DOT) {
498		int sep;
499
500		sep = sc_tokid;
501		expect(NUMBER);
502		mday = atol(sc_token);
503		if (token() == sep) {
504		    expect(NUMBER);
505		    year = atol(sc_token);
506		    token();
507		}
508
509		/* flip months and days for european timing
510		 */
511		if (sep == DOT) {
512		    int x = mday;
513		    mday = mon;
514		    mon = x;
515		}
516	    }
517	    else if (tlen == 6 || tlen == 8) {
518		if (tlen == 8) {
519		    year = (mon % 10000) - 1900;
520		    mon /= 10000;
521		}
522		else {
523		    year = mon % 100;
524		    mon /= 100;
525		}
526		mday = mon % 100;
527		mon /= 100;
528	    }
529	    else
530		panic("garbled time");
531
532	    mon--;
533	    if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
534		panic("garbled time");
535
536	    assign_date(tm, mday, mon, year);
537	    break;
538    } /* case */
539} /* month */
540
541
542/* Global functions */
543
544time_t
545parsetime(int argc, char **argv)
546{
547/* Do the argument parsing, die if necessary, and return the time the job
548 * should be run.
549 */
550    time_t nowtimer, runtimer;
551    struct tm nowtime, runtime;
552    int hr = 0;
553    /* this MUST be initialized to zero for midnight/noon/teatime */
554
555    nowtimer = time(NULL);
556    nowtime = *localtime(&nowtimer);
557
558    runtime = nowtime;
559    runtime.tm_sec = 0;
560    runtime.tm_isdst = 0;
561
562    if (argc <= optind)
563	usage();
564
565    init_scanner(argc-optind, argv+optind);
566
567    switch (token()) {
568    case NOW:	/* now is optional prefix for PLUS tree */
569	    expect(PLUS);
570    case PLUS:
571	    plus(&runtime);
572	    break;
573
574    case NUMBER:
575	    tod(&runtime);
576	    month(&runtime);
577	    break;
578
579	    /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
580	     * hr to zero up above, then fall into this case in such a
581	     * way so we add +12 +4 hours to it for teatime, +12 hours
582	     * to it for noon, and nothing at all for midnight, then
583	     * set our runtime to that hour before leaping into the
584	     * month scanner
585	     */
586    case TEATIME:
587	    hr += 4;
588    case NOON:
589	    hr += 12;
590    case MIDNIGHT:
591	    if (runtime.tm_hour >= hr) {
592		runtime.tm_mday++;
593		runtime.tm_wday++;
594	    }
595	    runtime.tm_hour = hr;
596	    runtime.tm_min = 0;
597	    token();
598	    /* fall through to month setting */
599    default:
600	    month(&runtime);
601	    break;
602    } /* ugly case statement */
603    expect(EOF);
604
605    /* adjust for daylight savings time
606     */
607    runtime.tm_isdst = -1;
608    runtimer = mktime(&runtime);
609    if (runtime.tm_isdst > 0) {
610	runtimer -= 3600;
611	runtimer = mktime(&runtime);
612    }
613
614    if (runtimer < 0)
615	panic("garbled time");
616
617    if (nowtimer > runtimer)
618	panic("Trying to travel back in time");
619
620    return runtimer;
621} /* parsetime */
622