1 /*- 2 * parsetime.c - parse time for at(1) 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (C) 1993, 1994 Thomas Koenig 7 * 8 * modifications for English-language times 9 * Copyright (C) 1993 David Parsons 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. The name of the author(s) may not be used to endorse or promote 17 * products derived from this software without specific prior written 18 * permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 * 31 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS 32 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \ 33 * |NOON | |[TOMORROW] | 34 * |MIDNIGHT | |[DAY OF WEEK] | 35 * \TEATIME / |NUMBER [SLASH NUMBER [SLASH NUMBER]]| 36 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/ 37 */ 38 39 #include <sys/cdefs.h> 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 <unistd.h> 51 #ifndef __FreeBSD__ 52 #include <getopt.h> 53 #endif 54 55 /* Local headers */ 56 57 #include "at.h" 58 #include "panic.h" 59 #include "parsetime.h" 60 61 62 /* Structures and unions */ 63 64 enum { /* symbols */ 65 MIDNIGHT, NOON, TEATIME, 66 PM, AM, TOMORROW, TODAY, NOW, 67 MINUTES, HOURS, DAYS, WEEKS, MONTHS, YEARS, 68 NUMBER, PLUS, MINUS, DOT, SLASH, ID, JUNK, 69 JAN, FEB, MAR, APR, MAY, JUN, 70 JUL, AUG, SEP, OCT, NOV, DEC, 71 SUN, MON, TUE, WED, THU, FRI, SAT 72 }; 73 74 /* parse translation table - table driven parsers can be your FRIEND! 75 */ 76 static const struct { 77 const char *name; /* token name */ 78 int value; /* token id */ 79 int plural; /* is this plural? */ 80 } Specials[] = { 81 { "midnight", MIDNIGHT,0 }, /* 00:00:00 of today or tomorrow */ 82 { "noon", NOON,0 }, /* 12:00:00 of today or tomorrow */ 83 { "teatime", TEATIME,0 }, /* 16:00:00 of today or tomorrow */ 84 { "am", AM,0 }, /* morning times for 0-12 clock */ 85 { "pm", PM,0 }, /* evening times for 0-12 clock */ 86 { "tomorrow", TOMORROW,0 }, /* execute 24 hours from time */ 87 { "today", TODAY, 0 }, /* execute today - don't advance time */ 88 { "now", NOW,0 }, /* opt prefix for PLUS */ 89 90 { "minute", MINUTES,0 }, /* minutes multiplier */ 91 { "minutes", MINUTES,1 }, /* (pluralized) */ 92 { "hour", HOURS,0 }, /* hours ... */ 93 { "hours", HOURS,1 }, /* (pluralized) */ 94 { "day", DAYS,0 }, /* days ... */ 95 { "days", DAYS,1 }, /* (pluralized) */ 96 { "week", WEEKS,0 }, /* week ... */ 97 { "weeks", WEEKS,1 }, /* (pluralized) */ 98 { "month", MONTHS,0 }, /* month ... */ 99 { "months", MONTHS,1 }, /* (pluralized) */ 100 { "year", YEARS,0 }, /* year ... */ 101 { "years", YEARS,1 }, /* (pluralized) */ 102 { "jan", JAN,0 }, 103 { "feb", FEB,0 }, 104 { "mar", MAR,0 }, 105 { "apr", APR,0 }, 106 { "may", MAY,0 }, 107 { "jun", JUN,0 }, 108 { "jul", JUL,0 }, 109 { "aug", AUG,0 }, 110 { "sep", SEP,0 }, 111 { "oct", OCT,0 }, 112 { "nov", NOV,0 }, 113 { "dec", DEC,0 }, 114 { "january", JAN,0 }, 115 { "february", FEB,0 }, 116 { "march", MAR,0 }, 117 { "april", APR,0 }, 118 { "may", MAY,0 }, 119 { "june", JUN,0 }, 120 { "july", JUL,0 }, 121 { "august", AUG,0 }, 122 { "september", SEP,0 }, 123 { "october", OCT,0 }, 124 { "november", NOV,0 }, 125 { "december", DEC,0 }, 126 { "sunday", SUN, 0 }, 127 { "sun", SUN, 0 }, 128 { "monday", MON, 0 }, 129 { "mon", MON, 0 }, 130 { "tuesday", TUE, 0 }, 131 { "tue", TUE, 0 }, 132 { "wednesday", WED, 0 }, 133 { "wed", WED, 0 }, 134 { "thursday", THU, 0 }, 135 { "thu", THU, 0 }, 136 { "friday", FRI, 0 }, 137 { "fri", FRI, 0 }, 138 { "saturday", SAT, 0 }, 139 { "sat", SAT, 0 }, 140 } ; 141 142 /* File scope variables */ 143 144 static char **scp; /* scanner - pointer at arglist */ 145 static char scc; /* scanner - count of remaining arguments */ 146 static char *sct; /* scanner - next char pointer in current argument */ 147 static int need; /* scanner - need to advance to next argument */ 148 149 static char *sc_token; /* scanner - token buffer */ 150 static size_t sc_len; /* scanner - length of token buffer */ 151 static int sc_tokid; /* scanner - token id */ 152 static int sc_tokplur; /* scanner - is token plural? */ 153 154 /* Local functions */ 155 156 /* 157 * parse a token, checking if it's something special to us 158 */ 159 static int 160 parse_token(char *arg) 161 { 162 size_t i; 163 164 for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++) 165 if (strcasecmp(Specials[i].name, arg) == 0) { 166 sc_tokplur = Specials[i].plural; 167 return sc_tokid = Specials[i].value; 168 } 169 170 /* not special - must be some random id */ 171 return ID; 172 } /* parse_token */ 173 174 175 /* 176 * init_scanner() sets up the scanner to eat arguments 177 */ 178 static void 179 init_scanner(int argc, char **argv) 180 { 181 scp = argv; 182 scc = argc; 183 need = 1; 184 sc_len = 1; 185 while (argc-- > 0) 186 sc_len += strlen(*argv++); 187 188 if ((sc_token = malloc(sc_len)) == NULL) 189 errx(EXIT_FAILURE, "virtual memory exhausted"); 190 } /* init_scanner */ 191 192 /* 193 * token() fetches a token from the input stream 194 */ 195 static int 196 token(void) 197 { 198 int idx; 199 200 while (1) { 201 memset(sc_token, 0, sc_len); 202 sc_tokid = EOF; 203 sc_tokplur = 0; 204 idx = 0; 205 206 /* if we need to read another argument, walk along the argument list; 207 * when we fall off the arglist, we'll just return EOF forever 208 */ 209 if (need) { 210 if (scc < 1) 211 return sc_tokid; 212 sct = *scp; 213 scp++; 214 scc--; 215 need = 0; 216 } 217 /* eat whitespace now - if we walk off the end of the argument, 218 * we'll continue, which puts us up at the top of the while loop 219 * to fetch the next argument in 220 */ 221 while (isspace(*sct)) 222 ++sct; 223 if (!*sct) { 224 need = 1; 225 continue; 226 } 227 228 /* preserve the first character of the new token 229 */ 230 sc_token[0] = *sct++; 231 232 /* then see what it is 233 */ 234 if (isdigit(sc_token[0])) { 235 while (isdigit(*sct)) 236 sc_token[++idx] = *sct++; 237 sc_token[++idx] = 0; 238 return sc_tokid = NUMBER; 239 } 240 else if (isalpha(sc_token[0])) { 241 while (isalpha(*sct)) 242 sc_token[++idx] = *sct++; 243 sc_token[++idx] = 0; 244 return parse_token(sc_token); 245 } 246 else if (sc_token[0] == ':' || sc_token[0] == '.') 247 return sc_tokid = DOT; 248 else if (sc_token[0] == '+') 249 return sc_tokid = PLUS; 250 else if (sc_token[0] == '-') 251 return sc_tokid = MINUS; 252 else if (sc_token[0] == '/') 253 return sc_tokid = SLASH; 254 else 255 return sc_tokid = JUNK; 256 } /* while (1) */ 257 } /* token */ 258 259 260 /* 261 * plonk() gives an appropriate error message if a token is incorrect 262 */ 263 static void 264 plonk(int tok) 265 { 266 panic((tok == EOF) ? "incomplete time" 267 : "garbled time"); 268 } /* plonk */ 269 270 271 /* 272 * expect() gets a token and dies most horribly if it's not the token we want 273 */ 274 static void 275 expect(int desired) 276 { 277 if (token() != desired) 278 plonk(sc_tokid); /* and we die here... */ 279 } /* expect */ 280 281 282 /* 283 * plus_or_minus() holds functionality common to plus() and minus() 284 */ 285 static void 286 plus_or_minus(struct tm *tm, int delay) 287 { 288 int expectplur; 289 290 expectplur = (delay != 1 && delay != -1) ? 1 : 0; 291 292 switch (token()) { 293 case YEARS: 294 tm->tm_year += delay; 295 break; 296 case MONTHS: 297 tm->tm_mon += delay; 298 break; 299 case WEEKS: 300 delay *= 7; 301 case DAYS: 302 tm->tm_mday += delay; 303 break; 304 case HOURS: 305 tm->tm_hour += delay; 306 break; 307 case MINUTES: 308 tm->tm_min += delay; 309 break; 310 default: 311 plonk(sc_tokid); 312 break; 313 } 314 315 if (expectplur != sc_tokplur) 316 warnx("pluralization is wrong"); 317 318 tm->tm_isdst = -1; 319 if (mktime(tm) < 0) 320 plonk(sc_tokid); 321 } /* plus_or_minus */ 322 323 324 /* 325 * plus() parses a now + time 326 * 327 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS|MONTHS|YEARS] 328 * 329 */ 330 static void 331 plus(struct tm *tm) 332 { 333 int delay; 334 335 expect(NUMBER); 336 337 delay = atoi(sc_token); 338 plus_or_minus(tm, delay); 339 } /* plus */ 340 341 342 /* 343 * minus() is like plus but can not be used with NOW 344 */ 345 static void 346 minus(struct tm *tm) 347 { 348 int delay; 349 350 expect(NUMBER); 351 352 delay = -atoi(sc_token); 353 plus_or_minus(tm, delay); 354 } /* minus */ 355 356 357 /* 358 * tod() computes the time of day 359 * [NUMBER [DOT NUMBER] [AM|PM]] 360 */ 361 static void 362 tod(struct tm *tm) 363 { 364 int hour, minute = 0; 365 int tlen; 366 367 hour = atoi(sc_token); 368 tlen = strlen(sc_token); 369 370 /* first pick out the time of day - if it's 4 digits, we assume 371 * a HHMM time, otherwise it's HH DOT MM time 372 */ 373 if (token() == DOT) { 374 expect(NUMBER); 375 minute = atoi(sc_token); 376 if (minute > 59) 377 panic("garbled time"); 378 token(); 379 } 380 else if (tlen == 4) { 381 minute = hour%100; 382 if (minute > 59) 383 panic("garbled time"); 384 hour = hour/100; 385 } 386 387 /* check if an AM or PM specifier was given 388 */ 389 if (sc_tokid == AM || sc_tokid == PM) { 390 if (hour > 12) 391 panic("garbled time"); 392 393 if (sc_tokid == PM) { 394 if (hour != 12) /* 12:xx PM is 12:xx, not 24:xx */ 395 hour += 12; 396 } else { 397 if (hour == 12) /* 12:xx AM is 00:xx, not 12:xx */ 398 hour = 0; 399 } 400 token(); 401 } 402 else if (hour > 23) 403 panic("garbled time"); 404 405 /* if we specify an absolute time, we don't want to bump the day even 406 * if we've gone past that time - but if we're specifying a time plus 407 * a relative offset, it's okay to bump things 408 */ 409 if ((sc_tokid == EOF || sc_tokid == PLUS || sc_tokid == MINUS) && 410 tm->tm_hour > hour) { 411 tm->tm_mday++; 412 tm->tm_wday++; 413 } 414 415 tm->tm_hour = hour; 416 tm->tm_min = minute; 417 if (tm->tm_hour == 24) { 418 tm->tm_hour = 0; 419 tm->tm_mday++; 420 } 421 } /* tod */ 422 423 424 /* 425 * assign_date() assigns a date, wrapping to next year if needed 426 */ 427 static void 428 assign_date(struct tm *tm, long mday, long mon, long year) 429 { 430 431 /* 432 * Convert year into tm_year format (year - 1900). 433 * We may be given the year in 2 digit, 4 digit, or tm_year format. 434 */ 435 if (year != -1) { 436 if (year >= 1900) 437 year -= 1900; /* convert from 4 digit year */ 438 else if (year < 100) { 439 /* convert from 2 digit year */ 440 struct tm *lt; 441 time_t now; 442 443 time(&now); 444 lt = localtime(&now); 445 446 /* Convert to tm_year assuming current century */ 447 year += (lt->tm_year / 100) * 100; 448 449 if (year == lt->tm_year - 1) year++; 450 else if (year < lt->tm_year) 451 year += 100; /* must be in next century */ 452 } 453 } 454 455 if (year < 0 && 456 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday))) 457 year = tm->tm_year + 1; 458 459 tm->tm_mday = mday; 460 tm->tm_mon = mon; 461 462 if (year >= 0) 463 tm->tm_year = year; 464 } /* assign_date */ 465 466 467 /* 468 * month() picks apart a month specification 469 * 470 * /[<month> NUMBER [NUMBER]] \ 471 * |[TOMORROW] | 472 * |[DAY OF WEEK] | 473 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]| 474 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/ 475 */ 476 static void 477 month(struct tm *tm) 478 { 479 long year= (-1); 480 long mday = 0, wday, mon; 481 int tlen; 482 483 switch (sc_tokid) { 484 case PLUS: 485 plus(tm); 486 break; 487 case MINUS: 488 minus(tm); 489 break; 490 491 case TOMORROW: 492 /* do something tomorrow */ 493 tm->tm_mday ++; 494 tm->tm_wday ++; 495 case TODAY: /* force ourselves to stay in today - no further processing */ 496 token(); 497 break; 498 499 case JAN: case FEB: case MAR: case APR: case MAY: case JUN: 500 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC: 501 /* do month mday [year] 502 */ 503 mon = (sc_tokid-JAN); 504 expect(NUMBER); 505 mday = atol(sc_token); 506 if (token() == NUMBER) { 507 year = atol(sc_token); 508 token(); 509 } 510 assign_date(tm, mday, mon, year); 511 break; 512 513 case SUN: case MON: case TUE: 514 case WED: case THU: case FRI: 515 case SAT: 516 /* do a particular day of the week 517 */ 518 wday = (sc_tokid-SUN); 519 520 mday = tm->tm_mday; 521 522 /* if this day is < today, then roll to next week 523 */ 524 if (wday < tm->tm_wday) 525 mday += 7 - (tm->tm_wday - wday); 526 else 527 mday += (wday - tm->tm_wday); 528 529 tm->tm_wday = wday; 530 531 assign_date(tm, mday, tm->tm_mon, tm->tm_year); 532 break; 533 534 case NUMBER: 535 /* get numeric MMDDYY, mm/dd/yy, or dd.mm.yy 536 */ 537 tlen = strlen(sc_token); 538 mon = atol(sc_token); 539 token(); 540 541 if (sc_tokid == SLASH || sc_tokid == DOT) { 542 int sep; 543 544 sep = sc_tokid; 545 expect(NUMBER); 546 mday = atol(sc_token); 547 if (token() == sep) { 548 expect(NUMBER); 549 year = atol(sc_token); 550 token(); 551 } 552 553 /* flip months and days for European timing 554 */ 555 if (sep == DOT) { 556 int x = mday; 557 mday = mon; 558 mon = x; 559 } 560 } 561 else if (tlen == 6 || tlen == 8) { 562 if (tlen == 8) { 563 year = (mon % 10000) - 1900; 564 mon /= 10000; 565 } 566 else { 567 year = mon % 100; 568 mon /= 100; 569 } 570 mday = mon % 100; 571 mon /= 100; 572 } 573 else 574 panic("garbled time"); 575 576 mon--; 577 if (mon < 0 || mon > 11 || mday < 1 || mday > 31) 578 panic("garbled time"); 579 580 assign_date(tm, mday, mon, year); 581 break; 582 } /* case */ 583 } /* month */ 584 585 586 /* Global functions */ 587 588 time_t 589 parsetime(int argc, char **argv) 590 { 591 /* Do the argument parsing, die if necessary, and return the time the job 592 * should be run. 593 */ 594 time_t nowtimer, runtimer; 595 struct tm nowtime, runtime; 596 int hr = 0; 597 /* this MUST be initialized to zero for midnight/noon/teatime */ 598 599 nowtimer = time(NULL); 600 nowtime = *localtime(&nowtimer); 601 602 runtime = nowtime; 603 runtime.tm_sec = 0; 604 runtime.tm_isdst = 0; 605 606 if (argc <= optind) 607 usage(); 608 609 init_scanner(argc-optind, argv+optind); 610 611 switch (token()) { 612 case NOW: 613 if (scc < 1) { 614 return nowtimer; 615 } 616 /* now is optional prefix for PLUS tree */ 617 expect(PLUS); 618 /* FALLTHROUGH */ 619 case PLUS: 620 plus(&runtime); 621 break; 622 623 /* MINUS is different from PLUS in that NOW is not 624 * an optional prefix for it 625 */ 626 case MINUS: 627 minus(&runtime); 628 break; 629 case NUMBER: 630 tod(&runtime); 631 month(&runtime); 632 break; 633 634 /* evil coding for TEATIME|NOON|MIDNIGHT - we've initialised 635 * hr to zero up above, then fall into this case in such a 636 * way so we add +12 +4 hours to it for teatime, +12 hours 637 * to it for noon, and nothing at all for midnight, then 638 * set our runtime to that hour before leaping into the 639 * month scanner 640 */ 641 case TEATIME: 642 hr += 4; 643 /* FALLTHROUGH */ 644 case NOON: 645 hr += 12; 646 /* FALLTHROUGH */ 647 case MIDNIGHT: 648 if (runtime.tm_hour >= hr) { 649 runtime.tm_mday++; 650 runtime.tm_wday++; 651 } 652 runtime.tm_hour = hr; 653 runtime.tm_min = 0; 654 token(); 655 /* FALLTHROUGH to month setting */ 656 default: 657 month(&runtime); 658 break; 659 } /* ugly case statement */ 660 expect(EOF); 661 662 /* convert back to time_t 663 */ 664 runtime.tm_isdst = -1; 665 runtimer = mktime(&runtime); 666 667 if (runtimer < 0) 668 panic("garbled time"); 669 670 if (nowtimer > runtimer) 671 panic("trying to travel back in time"); 672 673 return runtimer; 674 } /* parsetime */ 675