parsetime.c revision 1.1
1 /* 2 * parsetime.c - parse time for at(1) 3 * Copyright (C) 1993 Thomas Koenig 4 * 5 * modifications for english-language times 6 * Copyright (C) 1993 David Parsons 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. The name of the author(s) may not be used to endorse or promote 15 * products derived from this software without specific prior written 16 * permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * at [NOW] PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS 30 * /NUMBER [DOT NUMBER] [AM|PM]\ /[MONTH NUMBER [NUMBER]] \ 31 * |NOON | |[TOMORROW] | 32 * |MIDNIGHT | |NUMBER [SLASH NUMBER [SLASH NUMBER]]| 33 * \TEATIME / \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/ 34 */ 35 36 /* System Headers */ 37 38 #include <sys/types.h> 39 #include <errno.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <time.h> 44 #include <unistd.h> 45 #include <ctype.h> 46 47 /* Local headers */ 48 49 #include "at.h" 50 #include "panic.h" 51 52 53 /* Structures and unions */ 54 55 enum { /* symbols */ 56 MIDNIGHT, NOON, TEATIME, 57 PM, AM, TOMORROW, TODAY, NOW, 58 MINUTES, HOURS, DAYS, WEEKS, 59 NUMBER, PLUS, DOT, SLASH, ID, JUNK, 60 JAN, FEB, MAR, APR, MAY, JUN, 61 JUL, AUG, SEP, OCT, NOV, DEC 62 }; 63 64 /* 65 * parse translation table - table driven parsers can be your FRIEND! 66 */ 67 struct { 68 char *name; /* token name */ 69 int value; /* token id */ 70 } Specials[] = { 71 { "midnight", MIDNIGHT }, /* 00:00:00 of today or tomorrow */ 72 { "noon", NOON }, /* 12:00:00 of today or tomorrow */ 73 { "teatime", TEATIME }, /* 16:00:00 of today or tomorrow */ 74 { "am", AM }, /* morning times for 0-12 clock */ 75 { "pm", PM }, /* evening times for 0-12 clock */ 76 { "tomorrow", TOMORROW }, /* execute 24 hours from time */ 77 { "today", TODAY }, /* execute today - don't advance time */ 78 { "now", NOW }, /* opt prefix for PLUS */ 79 80 { "minute", MINUTES }, /* minutes multiplier */ 81 { "min", MINUTES }, 82 { "m", MINUTES }, 83 { "minutes", MINUTES }, /* (pluralized) */ 84 { "hour", HOURS }, /* hours ... */ 85 { "hr", HOURS }, /* abbreviated */ 86 { "h", HOURS }, 87 { "hours", HOURS }, /* (pluralized) */ 88 { "day", DAYS }, /* days ... */ 89 { "d", DAYS }, 90 { "days", DAYS }, /* (pluralized) */ 91 { "week", WEEKS }, /* week ... */ 92 { "w", WEEKS }, 93 { "weeks", WEEKS }, /* (pluralized) */ 94 { "jan", JAN }, 95 { "feb", FEB }, 96 { "mar", MAR }, 97 { "apr", APR }, 98 { "may", MAY }, 99 { "jun", JUN }, 100 { "jul", JUL }, 101 { "aug", AUG }, 102 { "sep", SEP }, 103 { "oct", OCT }, 104 { "nov", NOV }, 105 { "dec", DEC } 106 } ; 107 108 /* File scope variables */ 109 110 static char **scp; /* scanner - pointer at arglist */ 111 static char scc; /* scanner - count of remaining arguments */ 112 static char *sct; /* scanner - next char pointer in current argument */ 113 static int need; /* scanner - need to advance to next argument */ 114 115 static char *sc_token; /* scanner - token buffer */ 116 static size_t sc_len; /* scanner - lenght of token buffer */ 117 static int sc_tokid; /* scanner - token id */ 118 119 static char rcsid[] = "$Id: parsetime.c,v 1.1 1993/12/05 11:37:05 cgd Exp $"; 120 121 /* Local functions */ 122 123 /* 124 * parse a token, checking if it's something special to us 125 */ 126 static int 127 parse_token(arg) 128 char *arg; 129 { 130 int i; 131 132 for (i=0; i<(sizeof Specials/sizeof Specials[0]); i++) 133 if (strcasecmp(Specials[i].name, arg) == 0) { 134 return sc_tokid = Specials[i].value; 135 } 136 137 /* not special - must be some random id */ 138 return ID; 139 } /* parse_token */ 140 141 142 /* 143 * init_scanner() sets up the scanner to eat arguments 144 */ 145 static void 146 init_scanner(argc, argv) 147 int argc; 148 char **argv; 149 { 150 scp = argv; 151 scc = argc; 152 need = 1; 153 sc_len = 1; 154 while (--argc > 0) 155 sc_len += strlen(*++argv); 156 157 sc_token = (char *) malloc(sc_len); 158 if (sc_token == NULL) 159 panic("Insufficient virtual memory"); 160 } /* init_scanner */ 161 162 /* 163 * token() fetches a token from the input stream 164 */ 165 static int 166 token() 167 { 168 int idx; 169 170 while (1) { 171 memset(sc_token, 0, sc_len); 172 sc_tokid = EOF; 173 idx = 0; 174 175 /* 176 * if we need to read another argument, walk along the argument list; 177 * when we fall off the arglist, we'll just return EOF forever 178 */ 179 if (need) { 180 if (scc < 1) 181 return sc_tokid; 182 sct = *scp; 183 scp++; 184 scc--; 185 need = 0; 186 } 187 /* 188 * eat whitespace now - if we walk off the end of the argument, 189 * we'll continue, which puts us up at the top of the while loop 190 * to fetch the next argument in 191 */ 192 while (isspace(*sct)) 193 ++sct; 194 if (!*sct) { 195 need = 1; 196 continue; 197 } 198 199 /* 200 * preserve the first character of the new token 201 */ 202 sc_token[0] = *sct++; 203 204 /* 205 * then see what it is 206 */ 207 if (isdigit(sc_token[0])) { 208 while (isdigit(*sct)) 209 sc_token[++idx] = *sct++; 210 sc_token[++idx] = 0; 211 return sc_tokid = NUMBER; 212 } else if (isalpha(sc_token[0])) { 213 while (isalpha(*sct)) 214 sc_token[++idx] = *sct++; 215 sc_token[++idx] = 0; 216 return parse_token(sc_token); 217 } 218 else if (sc_token[0] == ':' || sc_token[0] == '.') 219 return sc_tokid = DOT; 220 else if (sc_token[0] == '+') 221 return sc_tokid = PLUS; 222 else if (*sct == '/') 223 return sc_tokid = SLASH; 224 else 225 return sc_tokid = JUNK; 226 } /* while (1) */ 227 } /* token */ 228 229 230 /* 231 * plonk() gives an appropriate error message if a token is incorrect 232 */ 233 static void 234 plonk(tok) 235 int tok; 236 { 237 panic((tok == EOF) ? "incomplete time" 238 : "garbled time"); 239 } /* plonk */ 240 241 242 /* 243 * expect() gets a token and dies most horribly if it's not the token we want 244 */ 245 static void 246 expect(desired) 247 int desired; 248 { 249 if (token() != desired) 250 plonk(sc_tokid); /* and we die here... */ 251 } /* expect */ 252 253 254 /* 255 * dateadd() adds a number of minutes to a date. It is extraordinarily 256 * stupid regarding day-of-month overflow, and will most likely not 257 * work properly 258 */ 259 static void 260 dateadd(minutes, tm) 261 int minutes; 262 struct tm *tm; 263 { 264 /* increment days */ 265 266 while (minutes > 24*60) { 267 minutes -= 24*60; 268 tm->tm_mday++; 269 } 270 271 /* increment hours */ 272 while (minutes > 60) { 273 minutes -= 60; 274 tm->tm_hour++; 275 if (tm->tm_hour > 23) { 276 tm->tm_mday++; 277 tm->tm_hour = 0; 278 } 279 } 280 281 /* increment minutes */ 282 tm->tm_min += minutes; 283 284 if (tm->tm_min > 59) { 285 tm->tm_hour++; 286 tm->tm_min -= 60; 287 288 if (tm->tm_hour > 23) { 289 tm->tm_mday++; 290 tm->tm_hour = 0; 291 } 292 } 293 } /* dateadd */ 294 295 296 /* 297 * plus() parses a now + time 298 * 299 * at [NOW] PLUS NUMBER [MINUTES|HOURS|DAYS|WEEKS] 300 * 301 */ 302 static void 303 plus(tm) 304 struct tm *tm; 305 { 306 int delay; 307 308 expect(NUMBER); 309 310 delay = atoi(sc_token); 311 312 switch (token()) { 313 case WEEKS: 314 delay *= 7; 315 case DAYS: 316 delay *= 24; 317 case HOURS: 318 delay *= 60; 319 case MINUTES: 320 dateadd(delay, tm); 321 return; 322 } 323 plonk(sc_tokid); 324 } /* plus */ 325 326 327 /* 328 * tod() computes the time of day 329 * [NUMBER [DOT NUMBER] [AM|PM]] 330 */ 331 static void 332 tod(tm) 333 struct tm *tm; 334 { 335 int hour, minute = 0; 336 int tlen; 337 338 hour = atoi(sc_token); 339 tlen = strlen(sc_token); 340 341 /* 342 * first pick out the time of day - if it's 4 digits, we assume 343 * a HHMM time, otherwise it's HH DOT MM time 344 */ 345 if (token() == DOT) { 346 expect(NUMBER); 347 minute = atoi(sc_token); 348 if (minute > 59) 349 panic("garbled time"); 350 token(); 351 } else if (tlen == 4) { 352 minute = hour%100; 353 if (minute > 59) 354 panic("garbeld time"); 355 hour = hour/100; 356 } 357 358 /* 359 * check if an AM or PM specifier was given 360 */ 361 if (sc_tokid == AM || sc_tokid == PM) { 362 if (hour > 12) 363 panic("garbled time"); 364 365 if (sc_tokid == PM) 366 hour += 12; 367 token(); 368 } else if (hour > 23) 369 panic("garbled time"); 370 371 /* 372 * if we specify an absolute time, we don't want to bump the day even 373 * if we've gone past that time - but if we're specifying a time plus 374 * a relative offset, it's okay to bump things 375 */ 376 if ((sc_tokid == EOF || sc_tokid == PLUS) && tm->tm_hour > hour) 377 tm->tm_mday++; 378 379 tm->tm_hour = hour; 380 tm->tm_min = minute; 381 if (tm->tm_hour == 24) { 382 tm->tm_hour = 0; 383 tm->tm_mday++; 384 } 385 } /* tod */ 386 387 388 /* 389 * assign_date() assigns a date, wrapping to next year if needed 390 */ 391 static void 392 assign_date(tm, mday, mon, year) 393 struct tm *tm; 394 long mday, mon, year; 395 { 396 if (year > 99) { 397 if (year > 1899) 398 year -= 1900; 399 else 400 panic("garbled time"); 401 } 402 403 if (year < 0 && 404 (tm->tm_mon > mon ||(tm->tm_mon == mon && tm->tm_mday > mday))) 405 year = tm->tm_year + 1; 406 407 tm->tm_mday = mday; 408 tm->tm_mon = mon; 409 410 if (year >= 0) 411 tm->tm_year = year; 412 } /* assign_date */ 413 414 415 /* 416 * month() picks apart a month specification 417 * 418 * /[<month> NUMBER [NUMBER]] \ 419 * |[TOMORROW] | 420 * |NUMBER [SLASH NUMBER [SLASH NUMBER]]| 421 * \PLUS NUMBER MINUTES|HOURS|DAYS|WEEKS/ 422 */ 423 static void 424 month(tm) 425 struct tm *tm; 426 { 427 long year= (-1); 428 long mday, mon; 429 int tlen; 430 431 switch (sc_tokid) { 432 case PLUS: 433 plus(tm); 434 break; 435 436 case TOMORROW: 437 /* do something tomorrow */ 438 tm->tm_mday ++; 439 case TODAY: /* force ourselves to stay in today - no further processing */ 440 token(); 441 break; 442 443 case JAN: case FEB: case MAR: case APR: case MAY: case JUN: 444 case JUL: case AUG: case SEP: case OCT: case NOV: case DEC: 445 /* 446 * do month mday [year] 447 */ 448 mon = (sc_tokid-JAN); 449 expect(NUMBER); 450 mday = atol(sc_token)-1; 451 if (token() == NUMBER) { 452 year = atol(sc_token); 453 token(); 454 } 455 assign_date(tm, mday, mon, year); 456 break; 457 458 case NUMBER: 459 /* 460 * get numeric MMDDYY, mm/dd/yy, or dd.mm.yy 461 */ 462 tlen = strlen(sc_token); 463 mon = atol(sc_token); 464 token(); 465 466 if (sc_tokid == SLASH || sc_tokid == DOT) { 467 int sep; 468 469 sep = sc_tokid; 470 expect(NUMBER); 471 mday = atol(sc_token); 472 if (token() == sep) { 473 expect(NUMBER); 474 year = atol(sc_token); 475 token(); 476 } 477 478 /* 479 * flip months and days for european timing 480 */ 481 if (sep == DOT) { 482 int x = mday; 483 mday = mon; 484 mon = x; 485 } 486 } else if (tlen == 6 || tlen == 8) { 487 if (tlen == 8) { 488 year = (mon % 10000) - 1900; 489 mon /= 10000; 490 } else { 491 year = mon % 100; 492 mon /= 100; 493 } 494 mday = mon % 100; 495 mon /= 100; 496 } else 497 panic("garbled time"); 498 499 mon--; 500 if (mon < 0 || mon > 11 || mday < 1 || mday > 31) 501 panic("garbled time"); 502 503 assign_date(tm, mday, mon, year); 504 break; 505 } /* case */ 506 } /* month */ 507 508 509 /* Global functions */ 510 511 time_t 512 parsetime(argc, argv) 513 int argc; 514 char **argv; 515 { 516 /* 517 * Do the argument parsing, die if necessary, and return the time the job 518 * should be run. 519 */ 520 time_t nowtimer, runtimer; 521 struct tm nowtime, runtime; 522 int hr = 0; 523 /* this MUST be initialized to zero for midnight/noon/teatime */ 524 525 nowtimer = time(NULL); 526 nowtime = *localtime(&nowtimer); 527 528 runtime = nowtime; 529 runtime.tm_sec = 0; 530 runtime.tm_isdst = 0; 531 532 if (argc <= optind) 533 usage(); 534 535 init_scanner(argc-optind, argv+optind); 536 537 switch (token()) { 538 case NOW: /* now is optional prefix for PLUS tree */ 539 expect(PLUS); 540 case PLUS: 541 plus(&runtime); 542 break; 543 544 case NUMBER: 545 tod(&runtime); 546 month(&runtime); 547 break; 548 549 /* 550 * evil coding for TEATIME|NOON|MIDNIGHT - we've initialised 551 * hr to zero up above, then fall into this case in such a 552 * way so we add +12 +4 hours to it for teatime, +12 hours 553 * to it for noon, and nothing at all for midnight, then 554 * set our runtime to that hour before leaping into the 555 * month scanner 556 */ 557 case TEATIME: 558 hr += 4; 559 case NOON: 560 hr += 12; 561 case MIDNIGHT: 562 if (runtime.tm_hour >= hr) 563 runtime.tm_mday++; 564 runtime.tm_hour = hr; 565 runtime.tm_min = 0; 566 token(); 567 /* fall through to month setting */ 568 default: 569 month(&runtime); 570 break; 571 } /* ugly case statement */ 572 expect(EOF); 573 574 /* 575 * adjust for daylight savings time 576 */ 577 runtime.tm_isdst = -1; 578 runtimer = mktime(&runtime); 579 if (runtime.tm_isdst > 0) { 580 runtimer -= 3600; 581 runtimer = mktime(&runtime); 582 } 583 584 if (runtimer < 0) 585 panic("garbled time"); 586 587 if (nowtimer > runtimer) 588 panic("Trying to travel back in time"); 589 590 return runtimer; 591 } /* parsetime */ 592
Indexes created Tue Oct 21 19:09:51 GMT 2025