system_cmds/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, NEXT
  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     { "next", NEXT, 0 },
 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 int 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 int sc_tokid;    /* scanner - token id */
 156 static int sc_tokplur;  /* scanner - is token plural? */
 157
 158 /* Local functions */
 159
 160 /*
 161  * parse a token, checking if it's something special to us
 162  */
 163 static int
 164 parse_token(char *arg)
 165 {
 166     size_t i;
 167
 168     for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
 169         if (strcasecmp(Specials[i].name, arg) == 0) {
 170             sc_tokplur = Specials[i].plural;
 171             return sc_tokid = Specials[i].value;
 172         }
 173
 174     /* not special - must be some random id */
 175     return sc_tokid = ID;
 176 } /* parse_token */
 177
 178
 179 /*
 180  * init_scanner() sets up the scanner to eat arguments
 181  */
 182 static void
 183 init_scanner(int argc, char **argv)
 184 {
 185     scp = argv;
 186     scc = argc;
 187     need = 1;
 188     sc_len = 1;
 189     while (argc-- > 0)
 190         sc_len += strlen(*argv++);
 191
 192     if ((sc_token = malloc(sc_len)) == NULL)
 193         errx(EXIT_FAILURE, "virtual memory exhausted");
 194 } /* init_scanner */
 195
 196 /*
 197  * token() fetches a token from the input stream
 198  */
 199 static int
 200 token(void)
 201 {
 202     int idx;
 203
 204     while (1) {
 205         memset(sc_token, 0, sc_len);
 206         sc_tokid = EOF;
 207         sc_tokplur = 0;
 208         idx = 0;
 209
 210         /* if we need to read another argument, walk along the argument list;
 211          * when we fall off the arglist, we'll just return EOF forever
 212          */
 213         if (need) {
 214             if (scc < 1)
 215                 return sc_tokid;
 216             sct = *scp;
 217             scp++;
 218             scc--;
 219             need = 0;
 220         }
 221         /* eat whitespace now - if we walk off the end of the argument,
 222          * we'll continue, which puts us up at the top of the while loop
 223          * to fetch the next argument in
 224          */
 225         while (isspace(*sct))
 226             ++sct;
 227         if (!*sct) {
 228             need = 1;
 229             continue;
 230         }
 231
 232         /* preserve the first character of the new token
 233          */
 234         sc_token[0] = *sct++;
 235
 236         /* then see what it is
 237          */
 238         if (isdigit(sc_token[0])) {
 239             while (isdigit(*sct))
 240                 sc_token[++idx] = *sct++;
 241             sc_token[++idx] = 0;
 242             return sc_tokid = NUMBER;
 243         }
 244         else if (isalpha(sc_token[0])) {
 245             while (isalpha(*sct))
 246                 sc_token[++idx] = *sct++;
 247             sc_token[++idx] = 0;
 248             return parse_token(sc_token);
 249         }
 250         else if (sc_token[0] == ':' || sc_token[0] == '.')
 251             return sc_tokid = DOT;
 252         else if (sc_token[0] == '+')
 253             return sc_tokid = PLUS;
 254         else if (sc_token[0] == '/')
 255             return sc_tokid = SLASH;
 256         else if (sc_token[0] == ',')
 257             return sc_tokid = COMMA;
 258         else
 259             return sc_tokid = JUNK;
 260     } /* while (1) */
 261 } /* token */
 262
 263
 264 /*
 265  * plonk() gives an appropriate error message if a token is incorrect
 266  */
 267 static void
 268 plonk(int tok)
 269 {
 270     panic((tok == EOF) ? "incomplete time"
 271                        : "garbled time");
 272 } /* plonk */
 273
 274
 275 /*
 276  * expect() gets a token and dies most horribly if it's not the token we want
 277  */
 278 static void
 279 expect(int desired)
 280 {
 281     if (token() != desired)
 282         plonk(sc_tokid);        /* and we die here... */
 283 } /* expect */
 284
 285
 286 /*
 287  * plus() parses a now + time
 288  *
 289  *  at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
 290  *
 291  */
 292
 293 static void
 294 plus(struct tm *tm)
 295 {
 296     int delay;
 297     int expectplur;
 298
 299     expect(NUMBER);
 300
 301     delay = atoi(sc_token);
 302     expectplur = (delay != 1) ? 1 : 0;
 303
 304     switch (token()) {
 305     case YEARS:
 306             tm->tm_year += delay;
 307             break;
 308     case MONTHS:
 309             tm->tm_mon += delay;
 310             break;
 311     case WEEKS:
 312             delay *= 7;
 313     case DAYS:
 314             tm->tm_mday += delay;
 315             break;
 316     case HOURS:
 317             tm->tm_hour += delay;
 318             break;
 319     case MINUTES:
 320             tm->tm_min += delay;
 321             break;
 322     default:
 323             plonk(sc_tokid);
 324             break;
 325     }
 326
 327     if (expectplur != sc_tokplur)
 328         warnx("pluralization is wrong");
 329
 330     tm->tm_isdst = -1;
 331     if (mktime(tm) < 0)
 332         plonk(sc_tokid);
 333
 334 } /* plus */
 335
 336 /*
 337  *  at [NOW] NEXT [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
 338  */
 339 static void
 340 next(struct tm *tm)
 341 {
 342     switch (token()) {
 343         case YEARS:
 344             tm->tm_year++;
 345             break;
 346
 347         case MONTHS:
 348             tm->tm_mon++;
 349             break;
 350
 351         case WEEKS:
 352             tm->tm_mday += 7;
 353             break;
 354
 355         case DAYS:
 356             tm->tm_mday++;
 357             break;
 358
 359         case HOURS:
 360             tm->tm_hour++;
 361             break;
 362
 363         case MINUTES:
 364             tm->tm_min++;
 365             break;
 366
 367         default:
 368             plonk(sc_tokid);
 369             break;
 370     }
 371
 372     if (sc_tokplur) {
 373         warnx("pluralization is wrong");
 374     }
 375     tm->tm_isdst = -1;
 376     if (mktime(tm) < 0) {
 377         plonk(sc_tokid);
 378     }
 379 } /* next */
 380
 381 /*
 382  * tod() computes the time of day
 383  *     [NUMBER [DOT NUMBER] [AM|PM]] [UTC]
 384  */
 385 static void
 386 tod(struct tm *tm)
 387 {
 388     int hour, minute = 0;
 389     size_t tlen;
 390
 391     hour = atoi(sc_token);
 392     tlen = strlen(sc_token);
 393
 394     /* first pick out the time of day - if it's 4 digits, we assume
 395      * a HHMM time, otherwise it's HH DOT MM time
 396      */
 397     if (token() == DOT) {
 398         expect(NUMBER);
 399         minute = atoi(sc_token);
 400         if (minute > 59)
 401             panic("garbled time");
 402         token();
 403     }
 404     else if (tlen == 4) {
 405         minute = hour%100;
 406         if (minute > 59)
 407             panic("garbled time");
 408         hour = hour/100;
 409     }
 410
 411     /* check if an AM or PM specifier was given
 412      */
 413     switch (sc_tokid) {
 414         case AM:
 415         case PM:
 416             if (hour > 12)
 417                 panic("garbled time");
 418
 419             if (sc_tokid == PM) {
 420                 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */
 421                     hour += 12;
 422             } else {
 423                 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */
 424                     hour = 0;
 425             }
 426             if (UTC != token())
 427                 break;          /* else fallthrough */
 428
 429         case UTC:
 430             hour += tm->tm_gmtoff/(60*60);
 431             while (hour < 0)
 432                 hour += 24;
 433             minute += (tm->tm_gmtoff/60);
 434             while (minute < 0)
 435                 minute += 60;
 436             tm->tm_gmtoff = 0;
 437             token();
 438             break;
 439         default:
 440             if (hour > 23)
 441                 panic("garbled time");
 442             break;
 443     }
 444
 445     /* if we specify an absolute time, we don't want to bump the day even
 446      * if we've gone past that time - but if we're specifying a time plus
 447      * a relative offset, it's okay to bump things
 448      * If minutes are the same assume tomorrow was meant
 449      */
 450     if ((sc_tokid == EOF || sc_tokid == PLUS) &&
 451         ((tm->tm_hour > hour) || ((tm->tm_hour == hour) && (tm->tm_min >= minute)))) {
 452         tm->tm_mday++;
 453         tm->tm_wday++;
 454     }
 455
 456     tm->tm_hour = hour;
 457     tm->tm_min = minute;
 458     if (tm->tm_hour == 24) {
 459         tm->tm_hour = 0;
 460         tm->tm_mday++;
 461     }
 462 } /* tod */
 463
 464
 465 /*
 466  * assign_date() assigns a date, wrapping to next year if needed
 467  */
 468 static void
 469 assign_date(struct tm *tm, int mday, int mon, int year)
 470 {
 471    /*
 472     * Convert year into tm_year format (year - 1900).
 473     * We may be given the year in 2 digit, 4 digit, or tm_year format.
 474     */
 475     if (year != -1) {
 476         if (year >= TM_YEAR_BASE)
 477                 year -= TM_YEAR_BASE;   /* convert from 4 digit year */
 478         else if (year < 100) {
 479                 /* convert from 2 digit year */
 480                 struct tm *lt;
 481                 time_t now;
 482
 483                 time(&now);
 484                 lt = localtime(&now);
 485
 486                 /* Convert to tm_year assuming current century */
 487                 year += (lt->tm_year / 100) * 100;
 488
 489                 if (year == lt->tm_year - 1) year++;
 490                 else if (year < lt->tm_year)
 491                         year += 100;    /* must be in next century */
 492         }
 493     }
 494
 495     if (year < 0 &&
 496         (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
 497         year = tm->tm_year + 1;
 498
 499     tm->tm_mday = mday;
 500     tm->tm_mon = mon;
 501
 502     if (year >= 0)
 503         tm->tm_year = year;
 504 } /* assign_date */
 505
 506
 507 /*
 508  * month() picks apart a month specification
 509  *
 510  *  /[<month> NUMBER [NUMBER]]           \
 511  *  |[TOMORROW]                          |
 512  *  |[DAY OF WEEK]                       |
 513  *  |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
 514  *  |NEXT MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS|
 515  *  \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
 516  */
 517 static void
 518 month(struct tm *tm)
 519 {
 520     int year= (-1);
 521     int mday = 0, wday, mon;
 522     int tlen;
 523
 524     switch (sc_tokid) {
 525     case PLUS:
 526             plus(tm);
 527             break;
 528
 529     case NEXT:
 530             next(tm);
 531             break;
 532
 533     case TOMORROW:
 534             /* do something tomorrow */
 535             tm->tm_mday ++;
 536             tm->tm_wday ++;
 537     case TODAY: /* force ourselves to stay in today - no further processing */
 538             token();
 539             break;
 540
 541     case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
 542     case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
 543             /* do month mday [,year]
 544              */
 545             mon = (sc_tokid-JAN);
 546             expect(NUMBER);
 547             mday = atoi(sc_token);
 548             if (token() == COMMA) {
 549                 if (token() == NUMBER) {
 550                     year = atoi(sc_token);
 551                     token();
 552                 }
 553             }
 554             assign_date(tm, mday, mon, year);
 555             if (sc_tokid == PLUS)
 556                     plus(tm);
 557             break;
 558
 559     case SUN: case MON: case TUE:
 560     case WED: case THU: case FRI:
 561     case SAT:
 562             /* do a particular day of the week
 563              */
 564             wday = (sc_tokid-SUN);
 565
 566             mday = tm->tm_mday;
 567
 568             /* if this day is < today, then roll to next week
 569              */
 570             if (wday < tm->tm_wday)
 571                 mday += 7 - (tm->tm_wday - wday);
 572             else
 573                 mday += (wday - tm->tm_wday);
 574
 575             tm->tm_wday = wday;
 576
 577             assign_date(tm, mday, tm->tm_mon, tm->tm_year);
 578             break;
 579
 580     case NUMBER:
 581             /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
 582              */
 583             tlen = (int)strlen(sc_token);
 584             mon = atoi(sc_token);
 585             token();
 586
 587             if (sc_tokid == SLASH || sc_tokid == DOT) {
 588                 int sep;
 589
 590                 sep = sc_tokid;
 591                 expect(NUMBER);
 592                 mday = atoi(sc_token);
 593                 if (token() == sep) {
 594                     expect(NUMBER);
 595                     year = atoi(sc_token);
 596                     token();
 597                 }
 598
 599                 /* flip months and days for European timing
 600                  */
 601                 if (sep == DOT) {
 602                     int x = mday;
 603                     mday = mon;
 604                     mon = x;
 605                 }
 606             }
 607             else if (tlen == 6 || tlen == 8) {
 608                 if (tlen == 8) {
 609                     year = (mon % 10000) - TM_YEAR_BASE;
 610                     mon /= 10000;
 611                 }
 612                 else {
 613                     year = mon % 100;
 614                     mon /= 100;
 615                 }
 616                 mday = mon % 100;
 617                 mon /= 100;
 618             }
 619             else
 620                 panic("garbled time");
 621
 622             mon--;
 623             if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
 624                 panic("garbled time");
 625
 626             assign_date(tm, mday, mon, year);
 627             break;
 628
 629     case EOF:
 630             break;
 631
 632     default:
 633             plonk(sc_tokid);
 634             break;
 635     } /* case */
 636 } /* month */
 637
 638
 639 /* Global functions */
 640
 641 time_t
 642 parsetime(int argc, char **argv)
 643 {
 644     /* Do the argument parsing, die if necessary, and return the time the job
 645      * should be run.
 646      */
 647     time_t nowtimer, runtimer;
 648     struct tm nowtime, runtime;
 649     int hr = 0;
 650     /* this MUST be initialized to zero for midnight/noon/teatime */
 651
 652     nowtimer = time(NULL);
 653     nowtime = *localtime(&nowtimer);
 654
 655     runtime = nowtime;
 656     runtime.tm_sec = 0;
 657     runtime.tm_isdst = 0;
 658
 659     if (argc <= optind)
 660         usage();
 661
 662     init_scanner(argc-optind, argv+optind);
 663
 664     switch (token()) {
 665         case NOW:
 666             if (scc < 1) {
 667                 return nowtimer;
 668             }
 669             /* now is optional prefix for PLUS/NEXT tree */
 670             switch (token()) {
 671                 case PLUS:
 672                     plus(&runtime);
 673                     break;
 674
 675                 case NEXT:
 676                     next(&runtime);
 677                     break;
 678
 679                 default:
 680                     plonk(sc_token);
 681                     break;
 682             }
 683             break;
 684
 685         case PLUS:
 686             plus(&runtime);
 687             break;
 688
 689         case NEXT:
 690             next(&runtime);
 691             break;
 692
 693         case NUMBER:
 694             tod(&runtime);
 695             month(&runtime);
 696             break;
 697
 698             /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
 699              * hr to zero up above, then fall into this case in such a
 700              * way so we add +12 +4 hours to it for teatime, +12 hours
 701              * to it for noon, and nothing at all for midnight, then
 702              * set our runtime to that hour before leaping into the
 703              * month scanner
 704              */
 705         case TEATIME:
 706             hr += 4;
 707         case NOON:
 708             hr += 12;
 709         case MIDNIGHT:
 710             if (runtime.tm_hour >= hr) {
 711                 runtime.tm_mday++;
 712                 runtime.tm_wday++;
 713             }
 714             runtime.tm_hour = hr;
 715             runtime.tm_min = 0;
 716             token();
 717             /* FALLTHROUGH to month setting */
 718         default:
 719             month(&runtime);
 720             break;
 721     } /* ugly case statement */
 722     expect(EOF);
 723
 724     /* convert back to time_t
 725      */
 726     runtime.tm_isdst = -1;
 727     runtimer = mktime(&runtime);
 728
 729     if (runtimer < 0)
 730         panic("garbled time");
 731
 732     if (nowtimer > runtimer)
 733         panic("trying to travel back in time");
 734
 735     return runtimer;
 736 } /* parsetime */