usr.bin/at/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  *     /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  * $FreeBSD: src/usr.bin/at/parsetime.c,v 1.27 2005/08/18 08:18:02 stefanf Exp $
  36  * $DragonFly: src/usr.bin/at/parsetime.c,v 1.6 2007/08/26 16:12:27 pavalos Exp $
  37  */
  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
  51 /* Local headers */
  52
  53 #include "at.h"
  54 #include "panic.h"
  55 #include "parsetime.h"
  56
  57
  58 /* Structures and unions */
  59
  60 enum {  /* symbols */
  61     MIDNIGHT, NOON, TEATIME,
  62     PM, AM, TOMORROW, TODAY, NOW,
  63     MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS,
  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  */
  72 struct {
  73     const 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     { "month", MONTHS,0 },      /* month ... */
  95     { "months", MONTHS,1 },     /* (pluralized) */
  96     { "year", YEARS,0 },        /* year ... */
  97     { "years", YEARS,1 },       /* (pluralized) */
  98     { "jan", JAN,0 },
  99     { "feb", FEB,0 },
 100     { "mar", MAR,0 },
 101     { "apr", APR,0 },
 102     { "may", MAY,0 },
 103     { "jun", JUN,0 },
 104     { "jul", JUL,0 },
 105     { "aug", AUG,0 },
 106     { "sep", SEP,0 },
 107     { "oct", OCT,0 },
 108     { "nov", NOV,0 },
 109     { "dec", DEC,0 },
 110     { "january", JAN,0 },
 111     { "february", FEB,0 },
 112     { "march", MAR,0 },
 113     { "april", APR,0 },
 114     { "may", MAY,0 },
 115     { "june", JUN,0 },
 116     { "july", JUL,0 },
 117     { "august", AUG,0 },
 118     { "september", SEP,0 },
 119     { "october", OCT,0 },
 120     { "november", NOV,0 },
 121     { "december", DEC,0 },
 122     { "sunday", SUN, 0 },
 123     { "sun", SUN, 0 },
 124     { "monday", MON, 0 },
 125     { "mon", MON, 0 },
 126     { "tuesday", TUE, 0 },
 127     { "tue", TUE, 0 },
 128     { "wednesday", WED, 0 },
 129     { "wed", WED, 0 },
 130     { "thursday", THU, 0 },
 131     { "thu", THU, 0 },
 132     { "friday", FRI, 0 },
 133     { "fri", FRI, 0 },
 134     { "saturday", SAT, 0 },
 135     { "sat", SAT, 0 },
 136 } ;
 137
 138 /* File scope variables */
 139
 140 static char **scp;      /* scanner - pointer at arglist */
 141 static char scc;        /* scanner - count of remaining arguments */
 142 static char *sct;       /* scanner - next char pointer in current argument */
 143 static int need;        /* scanner - need to advance to next argument */
 144
 145 static char *sc_token;  /* scanner - token buffer */
 146 static size_t sc_len;   /* scanner - length of token buffer */
 147 static int sc_tokid;    /* scanner - token id */
 148 static int sc_tokplur;  /* scanner - is token plural? */
 149
 150 /* Local functions */
 151
 152 /*
 153  * parse a token, checking if it's something special to us
 154  */
 155 static int
 156 parse_token(char *arg)
 157 {
 158     size_t i;
 159
 160     for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++)
 161         if (strcasecmp(Specials[i].name, arg) == 0) {
 162             sc_tokplur = Specials[i].plural;
 163             return sc_tokid = Specials[i].value;
 164         }
 165
 166     /* not special - must be some random id */
 167     return ID;
 168 } /* parse_token */
 169
 170
 171 /*
 172  * init_scanner() sets up the scanner to eat arguments
 173  */
 174 static void
 175 init_scanner(int argc, char **argv)
 176 {
 177     scp = argv;
 178     scc = argc;
 179     need = 1;
 180     sc_len = 1;
 181     while (argc-- > 0)
 182         sc_len += strlen(*argv++);
 183
 184     if ((sc_token = malloc(sc_len)) == NULL)
 185         errx(EXIT_FAILURE, "virtual memory exhausted");
 186 } /* init_scanner */
 187
 188 /*
 189  * token() fetches a token from the input stream
 190  */
 191 static int
 192 token(void)
 193 {
 194     int idx;
 195
 196     while (1) {
 197         memset(sc_token, 0, sc_len);
 198         sc_tokid = EOF;
 199         sc_tokplur = 0;
 200         idx = 0;
 201
 202         /* if we need to read another argument, walk along the argument list;
 203          * when we fall off the arglist, we'll just return EOF forever
 204          */
 205         if (need) {
 206             if (scc < 1)
 207                 return sc_tokid;
 208             sct = *scp;
 209             scp++;
 210             scc--;
 211             need = 0;
 212         }
 213         /* eat whitespace now - if we walk off the end of the argument,
 214          * we'll continue, which puts us up at the top of the while loop
 215          * to fetch the next argument in
 216          */
 217         while (isspace(*sct))
 218             ++sct;
 219         if (!*sct) {
 220             need = 1;
 221             continue;
 222         }
 223
 224         /* preserve the first character of the new token
 225          */
 226         sc_token[0] = *sct++;
 227
 228         /* then see what it is
 229          */
 230         if (isdigit(sc_token[0])) {
 231             while (isdigit(*sct))
 232                 sc_token[++idx] = *sct++;
 233             sc_token[++idx] = 0;
 234             return sc_tokid = NUMBER;
 235         }
 236         else if (isalpha(sc_token[0])) {
 237             while (isalpha(*sct))
 238                 sc_token[++idx] = *sct++;
 239             sc_token[++idx] = 0;
 240             return parse_token(sc_token);
 241         }
 242         else if (sc_token[0] == ':' || sc_token[0] == '.')
 243             return sc_tokid = DOT;
 244         else if (sc_token[0] == '+')
 245             return sc_tokid = PLUS;
 246         else if (sc_token[0] == '/')
 247             return sc_tokid = SLASH;
 248         else
 249             return sc_tokid = JUNK;
 250     } /* while (1) */
 251 } /* token */
 252
 253
 254 /*
 255  * plonk() gives an appropriate error message if a token is incorrect
 256  */
 257 static void
 258 plonk(int tok)
 259 {
 260     panic((tok == EOF) ? "incomplete time"
 261                        : "garbled time");
 262 } /* plonk */
 263
 264
 265 /*
 266  * expect() gets a token and dies most horribly if it's not the token we want
 267  */
 268 static void
 269 expect(int desired)
 270 {
 271     if (token() != desired)
 272         plonk(sc_tokid);        /* and we die here... */
 273 } /* expect */
 274
 275
 276 /*
 277  * plus() parses a now + time
 278  *
 279  *  at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS]
 280  *
 281  */
 282
 283 static void
 284 plus(struct tm *tm)
 285 {
 286     int delay;
 287     int expectplur;
 288
 289     expect(NUMBER);
 290
 291     delay = atoi(sc_token);
 292     expectplur = (delay != 1) ? 1 : 0;
 293
 294     switch (token()) {
 295     case YEARS:
 296             tm->tm_year += delay;
 297             break;
 298     case MONTHS:
 299             tm->tm_mon += delay;
 300             break;
 301     case WEEKS:
 302             delay *= 7;
 303     case DAYS:
 304             tm->tm_mday += delay;
 305             break;
 306     case HOURS:
 307             tm->tm_hour += delay;
 308             break;
 309     case MINUTES:
 310             tm->tm_min += delay;
 311             break;
 312     default:
 313             plonk(sc_tokid);
 314             break;
 315     }
 316
 317     if (expectplur != sc_tokplur)
 318         warnx("pluralization is wrong");
 319
 320     tm->tm_isdst = -1;
 321     if (mktime(tm) < 0)
 322         plonk(sc_tokid);
 323
 324 } /* plus */
 325
 326
 327 /*
 328  * tod() computes the time of day
 329  *     [NUMBER [DOT NUMBER] [AM|PM]]
 330  */
 331 static void
 332 tod(struct tm *tm)
 333 {
 334     int hour, minute = 0;
 335     int tlen;
 336
 337     hour = atoi(sc_token);
 338     tlen = strlen(sc_token);
 339
 340     /* first pick out the time of day - if it's 4 digits, we assume
 341      * a HHMM time, otherwise it's HH DOT MM time
 342      */
 343     if (token() == DOT) {
 344         expect(NUMBER);
 345         minute = atoi(sc_token);
 346         if (minute > 59)
 347             panic("garbled time");
 348         token();
 349     }
 350     else if (tlen == 4) {
 351         minute = hour%100;
 352         if (minute > 59)
 353             panic("garbled time");
 354         hour = hour/100;
 355     }
 356
 357     /* check if an AM or PM specifier was given
 358      */
 359     if (sc_tokid == AM || sc_tokid == PM) {
 360         if (hour > 12)
 361             panic("garbled time");
 362
 363         if (sc_tokid == PM) {
 364             if (hour != 12)     /* 12:xx PM is 12:xx, not 24:xx */
 365                         hour += 12;
 366         } else {
 367             if (hour == 12)     /* 12:xx AM is 00:xx, not 12:xx */
 368                         hour = 0;
 369         }
 370         token();
 371     }
 372     else if (hour > 23)
 373         panic("garbled time");
 374
 375     /* if we specify an absolute time, we don't want to bump the day even
 376      * if we've gone past that time - but if we're specifying a time plus
 377      * a relative offset, it's okay to bump things
 378      */
 379     if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) {
 380         tm->tm_mday++;
 381         tm->tm_wday++;
 382     }
 383
 384     tm->tm_hour = hour;
 385     tm->tm_min = minute;
 386     if (tm->tm_hour == 24) {
 387         tm->tm_hour = 0;
 388         tm->tm_mday++;
 389     }
 390 } /* tod */
 391
 392
 393 /*
 394  * assign_date() assigns a date, wrapping to next year if needed
 395  */
 396 static void
 397 assign_date(struct tm *tm, long mday, long mon, long year)
 398 {
 399
 400    /*
 401     * Convert year into tm_year format (year - 1900).
 402     * We may be given the year in 2 digit, 4 digit, or tm_year format.
 403     */
 404     if (year != -1) {
 405         if (year >= 1900)
 406                 year -= 1900;   /* convert from 4 digit year */
 407         else if (year < 100) {
 408                 /* convert from 2 digit year */
 409                 struct tm *lt;
 410                 time_t now;
 411
 412                 time(&now);
 413                 lt = localtime(&now);
 414
 415                 /* Convert to tm_year assuming current century */
 416                 year += (lt->tm_year / 100) * 100;
 417
 418                 if (year == lt->tm_year - 1) year++;
 419                 else if (year < lt->tm_year)
 420                         year += 100;    /* must be in next century */
 421         }
 422     }
 423
 424     if (year < 0 &&
 425         (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday)))
 426         year = tm->tm_year + 1;
 427
 428     tm->tm_mday = mday;
 429     tm->tm_mon = mon;
 430
 431     if (year >= 0)
 432         tm->tm_year = year;
 433 } /* assign_date */
 434
 435
 436 /*
 437  * month() picks apart a month specification
 438  *
 439  *  /[<month> NUMBER [NUMBER]]           \
 440  *  |[TOMORROW]                          |
 441  *  |[DAY OF WEEK]                       |
 442  *  |NUMBER [SLASH NUMBER [SLASH NUMBER]]|
 443  *  \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/
 444  */
 445 static void
 446 month(struct tm *tm)
 447 {
 448     long year= (-1);
 449     long mday = 0, wday, mon;
 450     int tlen;
 451
 452     switch (sc_tokid) {
 453     case PLUS:
 454             plus(tm);
 455             break;
 456
 457     case TOMORROW:
 458             /* do something tomorrow */
 459             tm->tm_mday ++;
 460             tm->tm_wday ++;
 461     case TODAY: /* force ourselves to stay in today - no further processing */
 462             token();
 463             break;
 464
 465     case JAN: case FEB: case MAR: case APR: case MAY: case JUN:
 466     case JUL: case AUG: case SEP: case OCT: case NOV: case DEC:
 467             /* do month mday [year]
 468              */
 469             mon = (sc_tokid-JAN);
 470             expect(NUMBER);
 471             mday = atol(sc_token);
 472             if (token() == NUMBER) {
 473                 year = atol(sc_token);
 474                 token();
 475             }
 476             assign_date(tm, mday, mon, year);
 477             break;
 478
 479     case SUN: case MON: case TUE:
 480     case WED: case THU: case FRI:
 481     case SAT:
 482             /* do a particular day of the week
 483              */
 484             wday = (sc_tokid-SUN);
 485
 486             mday = tm->tm_mday;
 487
 488             /* if this day is < today, then roll to next week
 489              */
 490             if (wday < tm->tm_wday)
 491                 mday += 7 - (tm->tm_wday - wday);
 492             else
 493                 mday += (wday - tm->tm_wday);
 494
 495             tm->tm_wday = wday;
 496
 497             assign_date(tm, mday, tm->tm_mon, tm->tm_year);
 498             break;
 499
 500     case NUMBER:
 501             /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy
 502              */
 503             tlen = strlen(sc_token);
 504             mon = atol(sc_token);
 505             token();
 506
 507             if (sc_tokid == SLASH || sc_tokid == DOT) {
 508                 int sep;
 509
 510                 sep = sc_tokid;
 511                 expect(NUMBER);
 512                 mday = atol(sc_token);
 513                 if (token() == sep) {
 514                     expect(NUMBER);
 515                     year = atol(sc_token);
 516                     token();
 517                 }
 518
 519                 /* flip months and days for European timing
 520                  */
 521                 if (sep == DOT) {
 522                     int x = mday;
 523                     mday = mon;
 524                     mon = x;
 525                 }
 526             }
 527             else if (tlen == 6 || tlen == 8) {
 528                 if (tlen == 8) {
 529                     year = (mon % 10000) - 1900;
 530                     mon /= 10000;
 531                 }
 532                 else {
 533                     year = mon % 100;
 534                     mon /= 100;
 535                 }
 536                 mday = mon % 100;
 537                 mon /= 100;
 538             }
 539             else
 540                 panic("garbled time");
 541
 542             mon--;
 543             if (mon < 0 || mon > 11 || mday < 1 || mday > 31)
 544                 panic("garbled time");
 545
 546             assign_date(tm, mday, mon, year);
 547             break;
 548     } /* case */
 549 } /* month */
 550
 551
 552 /* Global functions */
 553
 554 time_t
 555 parsetime(int argc, char **argv)
 556 {
 557 /* Do the argument parsing, die if necessary, and return the time the job
 558  * should be run.
 559  */
 560     time_t nowtimer, runtimer;
 561     struct tm nowtime, runtime;
 562     int hr = 0;
 563     /* this MUST be initialized to zero for midnight/noon/teatime */
 564
 565     nowtimer = time(NULL);
 566     nowtime = *localtime(&nowtimer);
 567
 568     runtime = nowtime;
 569     runtime.tm_sec = 0;
 570     runtime.tm_isdst = 0;
 571
 572     if (argc <= optind)
 573         usage();
 574
 575     init_scanner(argc-optind, argv+optind);
 576
 577     switch (token()) {
 578     case NOW:
 579             if (scc < 1) {
 580                 return nowtimer;
 581             }
 582             /* now is optional prefix for PLUS tree */
 583             expect(PLUS);
 584     case PLUS:
 585             plus(&runtime);
 586             break;
 587
 588     case NUMBER:
 589             tod(&runtime);
 590             month(&runtime);
 591             break;
 592
 593             /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised
 594              * hr to zero up above, then fall into this case in such a
 595              * way so we add +12 +4 hours to it for teatime, +12 hours
 596              * to it for noon, and nothing at all for midnight, then
 597              * set our runtime to that hour before leaping into the
 598              * month scanner
 599              */
 600     case TEATIME:
 601             hr += 4;
 602     case NOON:
 603             hr += 12;
 604     case MIDNIGHT:
 605             if (runtime.tm_hour >= hr) {
 606                 runtime.tm_mday++;
 607                 runtime.tm_wday++;
 608             }
 609             runtime.tm_hour = hr;
 610             runtime.tm_min = 0;
 611             token();
 612             /* FALLTHROUGH to month setting */
 613     default:
 614             month(&runtime);
 615             break;
 616     } /* ugly case statement */
 617     expect(EOF);
 618
 619     /* convert back to time_t
 620      */
 621     runtime.tm_isdst = -1;
 622     runtimer = mktime(&runtime);
 623
 624     if (runtimer < 0)
 625         panic("garbled time");
 626
 627     if (nowtimer > runtimer)
 628         panic("trying to travel back in time");
 629
 630     return runtimer;
 631 } /* parsetime */