at.tproj/parsetime.c

   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  * DOT ::= ':'|'.'
  30  *     /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]]             \
  31  *     |NOON                       | |[TOMORROW]                          |
  32  *     |MIDNIGHT                   | |[DAY OF WEEK]                       |
  33  *     \TEATIME                    / |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
  34  *                                   \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/usr.bin/at/parsetime.c,v 1.28 2011/11/06 17:32:29 ed Exp $");
  39
  40 /* System Headers */
  41
  42 #include <sys/types.h>
  43 #include <ctype.h>
  44 #include <err.h>
  45 #include <errno.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <time.h>
  50 #include <tzfile.h>
  51 #include <unistd.h>
  52 #ifndef __FreeBSD__
  53 #include <getopt.h>
  54 #endif
  55
  56 /* Local headers */
  57
  58 #include "at.h"
  59 #include "panic.h"
  60 #include "parsetime.h"
  61
  62
  63 /* Structures and unions */
  64
  65 enum {  /* symbols */
  66     MIDNIGHT, NOON, TEATIME,
  67     PM, AM, TOMORROW, TODAY, NOW,
  68     MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
  69     NUMBER, PLUS, DOT, COMMA, SLASH, ID, JUNK,
  70     JAN, FEB, MAR, APR, MAY, JUN,
  71     JUL, AUG, SEP, OCT, NOV, DEC,
  72     SUN, MON, TUE, WED, THU, FRI, SAT,
  73     UTC
  74     };
  75
  76 /* parse translation table - table driven parsers can be your FRIEND!
  77  */
  78 static const struct {
  79     const char *name;   /* token name */
  80     int value;  /* token id */
  81     int plural; /* is this plural? */
  82 } Specials[] = {
  83     { "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */
  84     { "noon", NOON,0 },         /* 12:00:00 of today or tomorrow */
  85     { "teatime", TEATIME,0 },   /* 16:00:00 of today or tomorrow */
  86     { "am", AM,0 },             /* morning times for 0-12 clock */
  87     { "pm", PM,0 },             /* evening times for 0-12 clock */
  88     { "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */
  89     { "today", TODAY, 0 },      /* execute today - don't advance time */
  90     { "now", NOW,0 },           /* opt prefix for PLUS */
  91
  92     { "minute", MINUTES,0 },    /* minutes multiplier */
  93     { "minutes", MINUTES,1 },   /* (pluralized) */
  94     { "hour", HOURS,0 },        /* hours ... */
  95     { "hours", HOURS,1 },       /* (pluralized) */
  96     { "day", DAYS,0 },          /* days ... */
  97     { "days", DAYS,1 },         /* (pluralized) */
  98     { "week", WEEKS,0 },        /* week ... */
  99     { "weeks", WEEKS,1 },       /* (pluralized) */
 100     { "month", MONTHS,0 },      /* month ... */
 101     { "months", MONTHS,1 },     /* (pluralized) */
 102     { "year", YEARS,0 },        /* year ... */
 103     { "years", YEARS,1 },       /* (pluralized) */
 104     { "jan", JAN,0 },
 105     { "feb", FEB,0 },
 106     { "mar", MAR,0 },
 107     { "apr", APR,0 },
 108     { "may", MAY,0 },
 109     { "jun", JUN,0 },
 110     { "jul", JUL,0 },
 111     { "aug", AUG,0 },
 112     { "sep", SEP,0 },
 113     { "oct", OCT,0 },
 114     { "nov", NOV,0 },
 115     { "dec", DEC,0 },
 116     { "january", JAN,0 },
 117     { "february", FEB,0 },
 118     { "march", MAR,0 },
 119     { "april", APR,0 },
 120     { "may", MAY,0 },
 121     { "june", JUN,0 },
 122     { "july", JUL,0 },
 123     { "august", AUG,0 },
 124     { "september", SEP,0 },
 125     { "october", OCT,0 },
 126     { "november", NOV,0 },
 127     { "december", DEC,0 },
 128     { "sunday", SUN, 0 },
 129     { "sun", SUN, 0 },
 130     { "monday", MON, 0 },
 131     { "mon", MON, 0 },
 132     { "tuesday", TUE, 0 },
 133     { "tue", TUE, 0 },
 134     { "wednesday", WED, 0 },
 135     { "wed", WED, 0 },
 136     { "thursday", THU, 0 },
 137     { "thu", THU, 0 },
 138     { "friday", FRI, 0 },
 139     { "fri", FRI, 0 },
 140     { "saturday", SAT, 0 },
 141     { "sat", SAT, 0 },
 142     { "utc", UTC, 0 },
 143 } ;
 144
 145 /* File scope variables */
 146
 147 static char **scp;      /* scanner - pointer at arglist */
 148 static char scc;        /* scanner - count of remaining arguments */
 149 static char *sct;       /* scanner - next char pointer in current argument */
 150 static int need;        /* scanner - need to advance to next argument */
 151
 152 static char *sc_token;  /* scanner - token buffer */
 153 static size_t sc_len;   /* scanner - length of token buffer */
 154 static int sc_tokid;    /* scanner - token id */
 155 static int sc_tokplur;  /* scanner - is token plural? */
 156
 157 /* Local functions */
 158
 159 /*
 160  * parse a token, checking if it's something special to us
 161  */
 162 static int
 163 parse_token(char *arg)
 164 {
 165     size_t i;
 166
 167     for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
 168         if (strcasecmp(Specials[i].name, arg) == 0) {
 169             sc_tokplur = Specials[i].plural;
 170             return sc_tokid = Specials[i].value;
 171         }
 172
 173     /* not special - must be some random id */
 174     return ID;
 175 } /* parse_token */
 176
 177
 178 /*
 179  * init_scanner() sets up the scanner to eat arguments
 180  */
 181 static void
 182 init_scanner(int argc, char **argv)
 183 {
 184     scp = argv;
 185     scc = argc;
 186     need = 1;
 187     sc_len = 1;
 188     while (argc-- > 0)
 189         sc_len += strlen(*argv++);
 190
 191     if ((sc_token = malloc(sc_len)) == NULL)
 192         errx(EXIT_FAILURE, "virtual memory exhausted");
 193 } /* init_scanner */
 194
 195 /*
 196  * token() fetches a token from the input stream
 197  */
 198 static int
 199 token(void)
 200 {
 201     int idx;
 202
 203     while (1) {
 204         memset(sc_token, 0, sc_len);
 205         sc_tokid = EOF;
 206         sc_tokplur = 0;
 207         idx = 0;
 208
 209         /* if we need to read another argument, walk along the argument list;
 210          * when we fall off the arglist, we'll just return EOF forever
 211          */
 212         if (need) {
 213             if (scc < 1)
 214                 return sc_tokid;
 215             sct = *scp;
 216             scp++;
 217             scc--;
 218             need = 0;
 219         }
 220         /* eat whitespace now - if we walk off the end of the argument,
 221          * we'll continue, which puts us up at the top of the while loop
 222          * to fetch the next argument in
 223          */
 224         while (isspace(*sct))
 225             ++sct;
 226         if (!*sct) {
 227             need = 1;
 228             continue;
 229         }
 230
 231         /* preserve the first character of the new token
 232          */
 233         sc_token[0] = *sct++;
 234
 235         /* then see what it is
 236          */
 237         if (isdigit(sc_token[0])) {
 238             while (isdigit(*sct))
 239                 sc_token[++idx] = *sct++;
 240             sc_token[++idx] = 0;
 241             return sc_tokid = NUMBER;
 242         }
 243         else if (isalpha(sc_token[0])) {
 244             while (isalpha(*sct))
 245                 sc_token[++idx] = *sct++;
 246             sc_token[++idx] = 0;
 247             return parse_token(sc_token);
 248         }
 249         else if (sc_token[0] == ':' || sc_token[0] == '.')
 250             return sc_tokid = DOT;
 251         else if (sc_token[0] == '+')
 252             return sc_tokid = PLUS;
 253         else if (sc_token[0] == '/')
 254             return sc_tokid = SLASH;
 255         else if (sc_token[0] == ',')
 256             return sc_tokid = COMMA;
 257         else
 258             return sc_tokid = JUNK;
 259     } /* while (1) */
 260 } /* token */
 261
 262
 263 /*
 264  * plonk() gives an appropriate error message if a token is incorrect
 265  */
 266 static void
 267 plonk(int tok)
 268 {
 269     panic((tok == EOF) ? "incomplete time"
 270                        : "garbled time");
 271 } /* plonk */
 272
 273
 274 /*
 275  * expect() gets a token and dies most horribly if it's not the token we want
 276  */
 277 static void
 278 expect(int desired)
 279 {
 280     if (token() != desired)
 281         plonk(sc_tokid);        /* and we die here... */
 282 } /* expect */
 283
 284
 285 /*
 286  * plus() parses a now + time
 287  *
 288  *  at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
 289  *
 290  */
 291
 292 static void
 293 plus(struct tm *tm)
 294 {
 295     int delay;
 296     int expectplur;
 297
 298     expect(NUMBER);
 299
 300     delay = atoi(sc_token);
 301     expectplur = (delay != 1) ? 1 : 0;
 302
 303     switch (token()) {
 304     case YEARS:
 305             tm->tm_year += delay;
 306             break;
 307     case MONTHS:
 308             tm->tm_mon += delay;
 309             break;
 310     case WEEKS:
 311             delay *= 7;
 312     case DAYS:
 313             tm->tm_mday += delay;
 314             break;
 315     case HOURS:
 316             tm->tm_hour += delay;
 317             break;
 318     case MINUTES:
 319             tm->tm_min += delay;
 320             break;
 321     default:
 322             plonk(sc_tokid);
 323             break;
 324     }
 325
 326     if (expectplur != sc_tokplur)
 327         warnx("pluralization is wrong");
 328
 329     tm->tm_isdst = -1;
 330     if (mktime(tm) < 0)
 331         plonk(sc_tokid);
 332
 333 } /* plus */
 334
 335
 336 /*
 337  * tod() computes the time of day
 338  *     [NUMBER [DOT NUMBER] [AM|PM]] [UTC]
 339  */
 340 static void
 341 tod(struct tm *tm)
 342 {
 343     int hour, minute = 0;
 344     size_t tlen;
 345
 346     hour = atoi(sc_token);
 347     tlen = strlen(sc_token);
 348
 349     /* first pick out the time of day - if it's 4 digits, we assume
 350      * a HHMM time, otherwise it's HH DOT MM time
 351      */
 352     if (token() == DOT) {
 353         expect(NUMBER);
 354         minute = atoi(sc_token);
 355         if (minute > 59)
 356             panic("garbled time");
 357         token();
 358     }
 359     else if (tlen == 4) {
 360         minute = hour%100;
 361         if (minute > 59)
 362             panic("garbled time");
 363         hour = hour/100;
 364     }
 365
 366     /* check if an AM or PM specifier was given
 367      */
 368     switch (sc_tokid) {
 369     case AM:
 370     case PM:
 371         if (hour > 12)
 372             panic("garbled time");
 373
 374         if (sc_tokid == PM) {
 375             if (hour != 12)     /* 12:xx PM is 12:xx, not 24:xx */
 376                 hour += 12;
 377         } else {
 378             if (hour == 12)     /* 12:xx AM is 00:xx, not 12:xx */
 379                 hour = 0;
 380         }
 381         if (UTC != token())
 382              break;             /* else fallthrough */
 383
 384     case UTC:
 385          hour += tm->tm_gmtoff/(60*60);
 386          while (hour < 0)
 387              hour += 24;
 388          minute += (tm->tm_gmtoff/60);
 389          while (minute < 0)
 390              minute += 60;
 391          tm->tm_gmtoff = 0;
 392          token();
 393          break;
 394     default:
 395         if (hour > 23)
 396             panic("garbled time");
 397         break;
 398     }
 399
 400     /* if we specify an absolute time, we don't want to bump the day even
 401      * if we've gone past that time - but if we're specifying a time plus
 402      * a relative offset, it's okay to bump things
 403      * If minutes are the same assume tomorrow was meant
 404      */
 405     if ((sc_tokid == EOF || sc_tokid == PLUS) &&
 406         ((tm->tm_hour > hour) || ((tm->tm_hour == hour) && (tm->tm_min >= minute)))) {
 407         tm->tm_mday++;
 408         tm->tm_wday++;
 409     }
 410
 411     tm->tm_hour = hour;
 412     tm->tm_min = minute;
 413     if (tm->tm_hour == 24) {
 414         tm->tm_hour = 0;
 415         tm->tm_mday++;
 416     }
 417 } /* tod */
 418
 419
 420 /*
 421  * assign_date() assigns a date, wrapping to next year if needed
 422  */
 423 static void
 424 assign_date(struct tm *tm, long mday, long mon, long year)
 425 {
 426    /*
 427     * Convert year into tm_year format (year - 1900).
 428     * We may be given the year in 2 digit, 4 digit, or tm_year format.
 429     */
 430     if (year != -1) {
 431         if (year >= TM_YEAR_BASE)
 432                 year -= TM_YEAR_BASE;   /* convert from 4 digit year */
 433         else if (year < 100) {
 434                 /* convert from 2 digit year */
 435                 struct tm *lt;
 436                 time_t now;
 437
 438                 time(&now);
 439                 lt = localtime(&now);
 440
 441                 /* Convert to tm_year assuming current century */
 442                 year += (lt->tm_year / 100) * 100;
 443
 444                 if (year == lt->tm_year - 1) year++;
 445                 else if (year < lt->tm_year)
 446                         year += 100;    /* must be in next century */
 447         }
 448     }
 449
 450     if (year < 0 &&
 451         (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
 452         year = tm->tm_year + 1;
 453
 454     tm->tm_mday = mday;
 455     tm->tm_mon = mon;
 456
 457     if (year >= 0)
 458         tm->tm_year = year;
 459 } /* assign_date */
 460
 461
 462 /*
 463  * month() picks apart a month specification
 464  *
 465  *  /[<month> NUMBER [NUMBER]]           \
 466  *  |[TOMORROW]                          |
 467  *  |[DAY OF WEEK]                       |
 468  *  |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
 469  *  \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
 470  */
 471 static void
 472 month(struct tm *tm)
 473 {
 474     long year= (-1);
 475     long mday = 0, wday, mon;
 476     int tlen;
 477
 478     switch (sc_tokid) {
 479     case PLUS:
 480             plus(tm);
 481             break;
 482
 483     case TOMORROW:
 484             /* do something tomorrow */
 485             tm->tm_mday ++;
 486             tm->tm_wday ++;
 487     case TODAY: /* force ourselves to stay in today - no further processing */
 488             token();
 489             break;
 490
 491     case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
 492     case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
 493             /* do month mday [,year]
 494              */
 495             mon = (sc_tokid-JAN);
 496             expect(NUMBER);
 497             mday = atol(sc_token);
 498             if (token() == COMMA) {
 499                 if (token() == NUMBER) {
 500                     year = atol(sc_token);
 501                     token();
 502                 }
 503             }
 504             assign_date(tm, mday, mon, year);
 505             if (sc_tokid == PLUS)
 506                     plus(tm);
 507             break;
 508
 509     case SUN: case MON: case TUE:
 510     case WED: case THU: case FRI:
 511     case SAT:
 512             /* do a particular day of the week
 513              */
 514             wday = (sc_tokid-SUN);
 515
 516             mday = tm->tm_mday;
 517
 518             /* if this day is < today, then roll to next week
 519              */
 520             if (wday < tm->tm_wday)
 521                 mday += 7 - (tm->tm_wday - wday);
 522             else
 523                 mday += (wday - tm->tm_wday);
 524
 525             tm->tm_wday = wday;
 526
 527             assign_date(tm, mday, tm->tm_mon, tm->tm_year);
 528             break;
 529
 530     case NUMBER:
 531             /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
 532              */
 533             tlen = strlen(sc_token);
 534             mon = atol(sc_token);
 535             token();
 536
 537             if (sc_tokid == SLASH || sc_tokid == DOT) {
 538                 int sep;
 539
 540                 sep = sc_tokid;
 541                 expect(NUMBER);
 542                 mday = atol(sc_token);
 543                 if (token() == sep) {
 544                     expect(NUMBER);
 545                     year = atol(sc_token);
 546                     token();
 547                 }
 548
 549                 /* flip months and days for European timing
 550                  */
 551                 if (sep == DOT) {
 552                     int x = mday;
 553                     mday = mon;
 554                     mon = x;
 555                 }
 556             }
 557             else if (tlen == 6 || tlen == 8) {
 558                 if (tlen == 8) {
 559                     year = (mon % 10000) - TM_YEAR_BASE;
 560                     mon /= 10000;
 561                 }
 562                 else {
 563                     year = mon % 100;
 564                     mon /= 100;
 565                 }
 566                 mday = mon % 100;
 567                 mon /= 100;
 568             }
 569             else
 570                 panic("garbled time");
 571
 572             mon--;
 573             if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
 574                 panic("garbled time");
 575
 576             assign_date(tm, mday, mon, year);
 577             break;
 578     } /* case */
 579 } /* month */
 580
 581
 582 /* Global functions */
 583
 584 time_t
 585 parsetime(int argc, char **argv)
 586 {
 587 /* Do the argument parsing, die if necessary, and return the time the job
 588  * should be run.
 589  */
 590     time_t nowtimer, runtimer;
 591     struct tm nowtime, runtime;
 592     int hr = 0;
 593     /* this MUST be initialized to zero for midnight/noon/teatime */
 594
 595     nowtimer = time(NULL);
 596     nowtime = *localtime(&nowtimer);
 597
 598     runtime = nowtime;
 599     runtime.tm_sec = 0;
 600     runtime.tm_isdst = 0;
 601
 602     if (argc <= optind)
 603         usage();
 604
 605     init_scanner(argc-optind, argv+optind);
 606
 607     switch (token()) {
 608     case NOW:
 609             if (scc < 1) {
 610                 return nowtimer;
 611             }
 612             /* now is optional prefix for PLUS tree */
 613             expect(PLUS);
 614     case PLUS:
 615             plus(&runtime);
 616             break;
 617
 618     case NUMBER:
 619             tod(&runtime);
 620             month(&runtime);
 621             break;
 622
 623             /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
 624              * hr to zero up above, then fall into this case in such a
 625              * way so we add +12 +4 hours to it for teatime, +12 hours
 626              * to it for noon, and nothing at all for midnight, then
 627              * set our runtime to that hour before leaping into the
 628              * month scanner
 629              */
 630     case TEATIME:
 631             hr += 4;
 632     case NOON:
 633             hr += 12;
 634     case MIDNIGHT:
 635             if (runtime.tm_hour >= hr) {
 636                 runtime.tm_mday++;
 637                 runtime.tm_wday++;
 638             }
 639             runtime.tm_hour = hr;
 640             runtime.tm_min = 0;
 641             token();
 642             /* FALLTHROUGH to month setting */
 643     default:
 644             month(&runtime);
 645             break;
 646     } /* ugly case statement */
 647     expect(EOF);
 648
 649     /* convert back to time_t
 650      */
 651     runtime.tm_isdst = -1;
 652     runtimer = mktime(&runtime);
 653
 654     if (runtimer < 0)
 655         panic("garbled time");
 656
 657     if (nowtimer > runtimer)
 658         panic("trying to travel back in time");
 659
 660     return runtimer;
 661 } /* parsetime */