1 /* $NetBSD: tm.c,v 1.4 2020/05/24 19:46:26 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * This Source Code Form is subject to the terms of the Mozilla Public 7 * License, v. 2.0. If a copy of the MPL was not distributed with this 8 * file, You can obtain one at http://mozilla.org/MPL/2.0/. 9 * 10 * See the COPYRIGHT file distributed with this work for additional 11 * information regarding copyright ownership. 12 */ 13 14 /*- 15 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc. 16 * All rights reserved. 17 * 18 * This code was contributed to The NetBSD Foundation by Klaus Klein. 19 * 20 * Redistribution and use in source and binary forms, with or without 21 * modification, are permitted provided that the following conditions 22 * are met: 23 * 1. Redistributions of source code must retain the above copyright 24 * notice, this list of conditions and the following disclaimer. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 39 * POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <ctype.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <time.h> 47 48 #include <isc/tm.h> 49 #include <isc/util.h> 50 51 /* 52 * Portable conversion routines for struct tm, replacing 53 * timegm() and strptime(), which are not available on all 54 * platforms and don't always behave the same way when they 55 * are. 56 */ 57 58 /* 59 * We do not implement alternate representations. However, we always 60 * check whether a given modifier is allowed for a certain conversion. 61 */ 62 #define ALT_E 0x01 63 #define ALT_O 0x02 64 #define LEGAL_ALT(x) \ 65 { \ 66 if ((alt_format & ~(x)) != 0) \ 67 return ((0)); \ 68 } 69 70 #ifndef TM_YEAR_BASE 71 #define TM_YEAR_BASE 1900 72 #endif /* ifndef TM_YEAR_BASE */ 73 74 static const char *day[7] = { "Sunday", "Monday", "Tuesday", "Wednesday", 75 "Thursday", "Friday", "Saturday" }; 76 static const char *abday[7] = { 77 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" 78 }; 79 static const char *mon[12] = { 80 "January", "February", "March", "April", "May", "June", 81 "July", "August", "September", "October", "November", "December" 82 }; 83 static const char *abmon[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", 84 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; 85 static const char *am_pm[2] = { "AM", "PM" }; 86 87 static int 88 conv_num(const char **buf, int *dest, int llim, int ulim) { 89 int result = 0; 90 91 /* The limit also determines the number of valid digits. */ 92 int rulim = ulim; 93 94 if (**buf < '0' || **buf > '9') { 95 return (0); 96 } 97 98 do { 99 result *= 10; 100 result += *(*buf)++ - '0'; 101 rulim /= 10; 102 } while ((result * 10 <= ulim) && rulim && **buf >= '0' && 103 **buf <= '9'); 104 105 if (result < llim || result > ulim) { 106 return (0); 107 } 108 109 *dest = result; 110 return (1); 111 } 112 113 time_t 114 isc_tm_timegm(struct tm *tm) { 115 time_t ret; 116 int i, yday = 0, leapday; 117 int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30 }; 118 119 leapday = ((((tm->tm_year + 1900) % 4) == 0 && 120 ((tm->tm_year + 1900) % 100) != 0) || 121 ((tm->tm_year + 1900) % 400) == 0) 122 ? 1 123 : 0; 124 mdays[1] += leapday; 125 126 yday = tm->tm_mday - 1; 127 for (i = 1; i <= tm->tm_mon; i++) { 128 yday += mdays[i - 1]; 129 } 130 ret = tm->tm_sec + (60 * tm->tm_min) + (3600 * tm->tm_hour) + 131 (86400 * 132 (yday + ((tm->tm_year - 70) * 365) + ((tm->tm_year - 69) / 4) - 133 ((tm->tm_year - 1) / 100) + ((tm->tm_year + 299) / 400))); 134 return (ret); 135 } 136 137 char * 138 isc_tm_strptime(const char *buf, const char *fmt, struct tm *tm) { 139 char c, *ret; 140 const char *bp; 141 size_t len = 0; 142 int alt_format, i, split_year = 0; 143 144 REQUIRE(buf != NULL); 145 REQUIRE(fmt != NULL); 146 REQUIRE(tm != NULL); 147 148 memset(tm, 0, sizeof(struct tm)); 149 150 bp = buf; 151 152 while ((c = *fmt) != '\0') { 153 /* Clear `alternate' modifier prior to new conversion. */ 154 alt_format = 0; 155 156 /* Eat up white-space. */ 157 if (isspace((unsigned char)c)) { 158 while (isspace((unsigned char)*bp)) { 159 bp++; 160 } 161 162 fmt++; 163 continue; 164 } 165 166 if ((c = *fmt++) != '%') { 167 goto literal; 168 } 169 170 again: 171 switch (c = *fmt++) { 172 case '%': /* "%%" is converted to "%". */ 173 literal: 174 if (c != *bp++) { 175 return (0); 176 } 177 break; 178 179 /* 180 * "Alternative" modifiers. Just set the appropriate flag 181 * and start over again. 182 */ 183 case 'E': /* "%E?" alternative conversion modifier. */ 184 LEGAL_ALT(0); 185 alt_format |= ALT_E; 186 goto again; 187 188 case 'O': /* "%O?" alternative conversion modifier. */ 189 LEGAL_ALT(0); 190 alt_format |= ALT_O; 191 goto again; 192 193 /* 194 * "Complex" conversion rules, implemented through recursion. 195 */ 196 case 'c': /* Date and time, using the locale's format. */ 197 LEGAL_ALT(ALT_E); 198 if (!(bp = isc_tm_strptime(bp, "%x %X", tm))) { 199 return (0); 200 } 201 break; 202 203 case 'D': /* The date as "%m/%d/%y". */ 204 LEGAL_ALT(0); 205 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) { 206 return (0); 207 } 208 break; 209 210 case 'R': /* The time as "%H:%M". */ 211 LEGAL_ALT(0); 212 if (!(bp = isc_tm_strptime(bp, "%H:%M", tm))) { 213 return (0); 214 } 215 break; 216 217 case 'r': /* The time in 12-hour clock representation. */ 218 LEGAL_ALT(0); 219 if (!(bp = isc_tm_strptime(bp, "%I:%M:%S %p", tm))) { 220 return (0); 221 } 222 break; 223 224 case 'T': /* The time as "%H:%M:%S". */ 225 LEGAL_ALT(0); 226 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) { 227 return (0); 228 } 229 break; 230 231 case 'X': /* The time, using the locale's format. */ 232 LEGAL_ALT(ALT_E); 233 if (!(bp = isc_tm_strptime(bp, "%H:%M:%S", tm))) { 234 return (0); 235 } 236 break; 237 238 case 'x': /* The date, using the locale's format. */ 239 LEGAL_ALT(ALT_E); 240 if (!(bp = isc_tm_strptime(bp, "%m/%d/%y", tm))) { 241 return (0); 242 } 243 break; 244 245 /* 246 * "Elementary" conversion rules. 247 */ 248 case 'A': /* The day of week, using the locale's form. */ 249 case 'a': 250 LEGAL_ALT(0); 251 for (i = 0; i < 7; i++) { 252 /* Full name. */ 253 len = strlen(day[i]); 254 if (strncasecmp(day[i], bp, len) == 0) { 255 break; 256 } 257 258 /* Abbreviated name. */ 259 len = strlen(abday[i]); 260 if (strncasecmp(abday[i], bp, len) == 0) { 261 break; 262 } 263 } 264 265 /* Nothing matched. */ 266 if (i == 7) { 267 return (0); 268 } 269 270 tm->tm_wday = i; 271 bp += len; 272 break; 273 274 case 'B': /* The month, using the locale's form. */ 275 case 'b': 276 case 'h': 277 LEGAL_ALT(0); 278 for (i = 0; i < 12; i++) { 279 /* Full name. */ 280 len = strlen(mon[i]); 281 if (strncasecmp(mon[i], bp, len) == 0) { 282 break; 283 } 284 285 /* Abbreviated name. */ 286 len = strlen(abmon[i]); 287 if (strncasecmp(abmon[i], bp, len) == 0) { 288 break; 289 } 290 } 291 292 /* Nothing matched. */ 293 if (i == 12) { 294 return (0); 295 } 296 297 tm->tm_mon = i; 298 bp += len; 299 break; 300 301 case 'C': /* The century number. */ 302 LEGAL_ALT(ALT_E); 303 if (!(conv_num(&bp, &i, 0, 99))) { 304 return (0); 305 } 306 307 if (split_year) { 308 tm->tm_year = (tm->tm_year % 100) + (i * 100); 309 } else { 310 tm->tm_year = i * 100; 311 split_year = 1; 312 } 313 break; 314 315 case 'd': /* The day of month. */ 316 case 'e': 317 LEGAL_ALT(ALT_O); 318 if (!(conv_num(&bp, &tm->tm_mday, 1, 31))) { 319 return (0); 320 } 321 break; 322 323 case 'k': /* The hour (24-hour clock representation). */ 324 LEGAL_ALT(0); 325 /* FALLTHROUGH */ 326 case 'H': 327 LEGAL_ALT(ALT_O); 328 if (!(conv_num(&bp, &tm->tm_hour, 0, 23))) { 329 return (0); 330 } 331 break; 332 333 case 'l': /* The hour (12-hour clock representation). */ 334 LEGAL_ALT(0); 335 /* FALLTHROUGH */ 336 case 'I': 337 LEGAL_ALT(ALT_O); 338 if (!(conv_num(&bp, &tm->tm_hour, 1, 12))) { 339 return (0); 340 } 341 if (tm->tm_hour == 12) { 342 tm->tm_hour = 0; 343 } 344 break; 345 346 case 'j': /* The day of year. */ 347 LEGAL_ALT(0); 348 if (!(conv_num(&bp, &i, 1, 366))) { 349 return (0); 350 } 351 tm->tm_yday = i - 1; 352 break; 353 354 case 'M': /* The minute. */ 355 LEGAL_ALT(ALT_O); 356 if (!(conv_num(&bp, &tm->tm_min, 0, 59))) { 357 return (0); 358 } 359 break; 360 361 case 'm': /* The month. */ 362 LEGAL_ALT(ALT_O); 363 if (!(conv_num(&bp, &i, 1, 12))) { 364 return (0); 365 } 366 tm->tm_mon = i - 1; 367 break; 368 369 case 'p': /* The locale's equivalent of AM/PM. */ 370 LEGAL_ALT(0); 371 /* AM? */ 372 if (strcasecmp(am_pm[0], bp) == 0) { 373 if (tm->tm_hour > 11) { 374 return (0); 375 } 376 377 bp += strlen(am_pm[0]); 378 break; 379 } 380 /* PM? */ 381 else if (strcasecmp(am_pm[1], bp) == 0) 382 { 383 if (tm->tm_hour > 11) { 384 return (0); 385 } 386 387 tm->tm_hour += 12; 388 bp += strlen(am_pm[1]); 389 break; 390 } 391 392 /* Nothing matched. */ 393 return (0); 394 395 case 'S': /* The seconds. */ 396 LEGAL_ALT(ALT_O); 397 if (!(conv_num(&bp, &tm->tm_sec, 0, 61))) { 398 return (0); 399 } 400 break; 401 402 case 'U': /* The week of year, beginning on sunday. */ 403 case 'W': /* The week of year, beginning on monday. */ 404 LEGAL_ALT(ALT_O); 405 /* 406 * XXX This is bogus, as we can not assume any valid 407 * information present in the tm structure at this 408 * point to calculate a real value, so just check the 409 * range for now. 410 */ 411 if (!(conv_num(&bp, &i, 0, 53))) { 412 return (0); 413 } 414 break; 415 416 case 'w': /* The day of week, beginning on sunday. */ 417 LEGAL_ALT(ALT_O); 418 if (!(conv_num(&bp, &tm->tm_wday, 0, 6))) { 419 return (0); 420 } 421 break; 422 423 case 'Y': /* The year. */ 424 LEGAL_ALT(ALT_E); 425 if (!(conv_num(&bp, &i, 0, 9999))) { 426 return (0); 427 } 428 429 tm->tm_year = i - TM_YEAR_BASE; 430 break; 431 432 case 'y': /* The year within 100 years of the epoch. */ 433 LEGAL_ALT(ALT_E | ALT_O); 434 if (!(conv_num(&bp, &i, 0, 99))) { 435 return (0); 436 } 437 438 if (split_year) { 439 tm->tm_year = ((tm->tm_year / 100) * 100) + i; 440 break; 441 } 442 split_year = 1; 443 if (i <= 68) { 444 tm->tm_year = i + 2000 - TM_YEAR_BASE; 445 } else { 446 tm->tm_year = i + 1900 - TM_YEAR_BASE; 447 } 448 break; 449 450 /* 451 * Miscellaneous conversions. 452 */ 453 case 'n': /* Any kind of white-space. */ 454 case 't': 455 LEGAL_ALT(0); 456 while (isspace((unsigned char)*bp)) { 457 bp++; 458 } 459 break; 460 461 default: /* Unknown/unsupported conversion. */ 462 return (0); 463 } 464 } 465 466 /* LINTED functional specification */ 467 DE_CONST(bp, ret); 468 return (ret); 469 } 470