1 /* $OpenBSD: strftime.c,v 1.32 2019/06/29 16:12:21 deraadt Exp $ */ 2 /* 3 ** Copyright (c) 1989, 1993 4 ** The Regents of the University of California. All rights reserved. 5 ** 6 ** Redistribution and use in source and binary forms, with or without 7 ** modification, are permitted provided that the following conditions 8 ** are met: 9 ** 1. Redistributions of source code must retain the above copyright 10 ** notice, this list of conditions and the following disclaimer. 11 ** 2. Redistributions in binary form must reproduce the above copyright 12 ** notice, this list of conditions and the following disclaimer in the 13 ** documentation and/or other materials provided with the distribution. 14 ** 3. Neither the name of the University nor the names of its contributors 15 ** may be used to endorse or promote products derived from this software 16 ** without specific prior written permission. 17 ** 18 ** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 ** ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 ** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 ** SUCH DAMAGE. 29 */ 30 31 #include <fcntl.h> 32 #include <locale.h> 33 #include <stdio.h> 34 35 #include "private.h" 36 #include "tzfile.h" 37 38 struct lc_time_T { 39 const char * mon[MONSPERYEAR]; 40 const char * month[MONSPERYEAR]; 41 const char * wday[DAYSPERWEEK]; 42 const char * weekday[DAYSPERWEEK]; 43 const char * X_fmt; 44 const char * x_fmt; 45 const char * c_fmt; 46 const char * am; 47 const char * pm; 48 const char * date_fmt; 49 }; 50 51 #ifdef LOCALE_HOME 52 #include "sys/stat.h" 53 static struct lc_time_T localebuf; 54 static struct lc_time_T * _loc(void); 55 #define Locale _loc() 56 #endif /* defined LOCALE_HOME */ 57 #ifndef LOCALE_HOME 58 #define Locale (&C_time_locale) 59 #endif /* !defined LOCALE_HOME */ 60 61 static const struct lc_time_T C_time_locale = { 62 { 63 "Jan", "Feb", "Mar", "Apr", "May", "Jun", 64 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" 65 }, { 66 "January", "February", "March", "April", "May", "June", 67 "July", "August", "September", "October", "November", "December" 68 }, { 69 "Sun", "Mon", "Tue", "Wed", 70 "Thu", "Fri", "Sat" 71 }, { 72 "Sunday", "Monday", "Tuesday", "Wednesday", 73 "Thursday", "Friday", "Saturday" 74 }, 75 76 /* X_fmt */ 77 "%H:%M:%S", 78 79 /* 80 ** x_fmt 81 ** C99 requires this format. 82 ** Using just numbers (as here) makes Quakers happier; 83 ** it's also compatible with SVR4. 84 */ 85 "%m/%d/%y", 86 87 /* 88 ** c_fmt 89 ** C99 requires this format. 90 ** Previously this code used "%D %X", but we now conform to C99. 91 ** Note that 92 ** "%a %b %d %H:%M:%S %Y" 93 ** is used by Solaris 2.3. 94 */ 95 "%a %b %e %T %Y", 96 97 /* am */ 98 "AM", 99 100 /* pm */ 101 "PM", 102 103 /* date_fmt */ 104 "%a %b %e %H:%M:%S %Z %Y" 105 }; 106 107 static char * _add(const char *, char *, const char *); 108 static char * _conv(int, const char *, char *, const char *); 109 static char * _fmt(const char *, const struct tm *, char *, const char *, 110 int *); 111 static char * _yconv(int, int, int, int, char *, const char *); 112 113 extern char * tzname[]; 114 115 #define IN_NONE 0 116 #define IN_SOME 1 117 #define IN_THIS 2 118 #define IN_ALL 3 119 120 size_t 121 strftime(char *s, size_t maxsize, const char *format, const struct tm *t) 122 { 123 char * p; 124 int warn; 125 126 tzset(); 127 #ifdef LOCALE_HOME 128 localebuf.mon[0] = 0; 129 #endif /* defined LOCALE_HOME */ 130 warn = IN_NONE; 131 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn); 132 if (p == s + maxsize) { 133 if (maxsize > 0) 134 s[maxsize - 1] = '\0'; 135 return 0; 136 } 137 *p = '\0'; 138 return p - s; 139 } 140 DEF_STRONG(strftime); 141 142 static char * 143 _fmt(const char *format, const struct tm *t, char *pt, const char *ptlim, int *warnp) 144 { 145 for ( ; *format; ++format) { 146 if (*format == '%') { 147 label: 148 switch (*++format) { 149 case '\0': 150 --format; 151 break; 152 case 'A': 153 pt = _add((t->tm_wday < 0 || 154 t->tm_wday >= DAYSPERWEEK) ? 155 "?" : Locale->weekday[t->tm_wday], 156 pt, ptlim); 157 continue; 158 case 'a': 159 pt = _add((t->tm_wday < 0 || 160 t->tm_wday >= DAYSPERWEEK) ? 161 "?" : Locale->wday[t->tm_wday], 162 pt, ptlim); 163 continue; 164 case 'B': 165 pt = _add((t->tm_mon < 0 || 166 t->tm_mon >= MONSPERYEAR) ? 167 "?" : Locale->month[t->tm_mon], 168 pt, ptlim); 169 continue; 170 case 'b': 171 case 'h': 172 pt = _add((t->tm_mon < 0 || 173 t->tm_mon >= MONSPERYEAR) ? 174 "?" : Locale->mon[t->tm_mon], 175 pt, ptlim); 176 continue; 177 case 'C': 178 /* 179 ** %C used to do a... 180 ** _fmt("%a %b %e %X %Y", t); 181 ** ...whereas now POSIX 1003.2 calls for 182 ** something completely different. 183 ** (ado, 1993-05-24) 184 */ 185 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0, 186 pt, ptlim); 187 continue; 188 case 'c': 189 { 190 int warn2 = IN_SOME; 191 192 pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2); 193 if (warn2 == IN_ALL) 194 warn2 = IN_THIS; 195 if (warn2 > *warnp) 196 *warnp = warn2; 197 } 198 continue; 199 case 'D': 200 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp); 201 continue; 202 case 'd': 203 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 204 continue; 205 case 'E': 206 case 'O': 207 /* 208 ** C99 locale modifiers. 209 ** The sequences 210 ** %Ec %EC %Ex %EX %Ey %EY 211 ** %Od %oe %OH %OI %Om %OM 212 ** %OS %Ou %OU %OV %Ow %OW %Oy 213 ** are supposed to provide alternate 214 ** representations. 215 */ 216 goto label; 217 case 'e': 218 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 219 continue; 220 case 'F': 221 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp); 222 continue; 223 case 'H': 224 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 225 continue; 226 case 'I': 227 pt = _conv((t->tm_hour % 12) ? 228 (t->tm_hour % 12) : 12, 229 "%02d", pt, ptlim); 230 continue; 231 case 'j': 232 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 233 continue; 234 case 'k': 235 /* 236 ** This used to be... 237 ** _conv(t->tm_hour % 12 ? 238 ** t->tm_hour % 12 : 12, 2, ' '); 239 ** ...and has been changed to the below to 240 ** match SunOS 4.1.1 and Arnold Robbins' 241 ** strftime version 3.0. That is, "%k" and 242 ** "%l" have been swapped. 243 ** (ado, 1993-05-24) 244 */ 245 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 246 continue; 247 #ifdef KITCHEN_SINK 248 case 'K': 249 /* 250 ** After all this time, still unclaimed! 251 */ 252 pt = _add("kitchen sink", pt, ptlim); 253 continue; 254 #endif /* defined KITCHEN_SINK */ 255 case 'l': 256 /* 257 ** This used to be... 258 ** _conv(t->tm_hour, 2, ' '); 259 ** ...and has been changed to the below to 260 ** match SunOS 4.1.1 and Arnold Robbin's 261 ** strftime version 3.0. That is, "%k" and 262 ** "%l" have been swapped. 263 ** (ado, 1993-05-24) 264 */ 265 pt = _conv((t->tm_hour % 12) ? 266 (t->tm_hour % 12) : 12, 267 "%2d", pt, ptlim); 268 continue; 269 case 'M': 270 pt = _conv(t->tm_min, "%02d", pt, ptlim); 271 continue; 272 case 'm': 273 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 274 continue; 275 case 'n': 276 pt = _add("\n", pt, ptlim); 277 continue; 278 case 'p': 279 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 280 Locale->pm : 281 Locale->am, 282 pt, ptlim); 283 continue; 284 case 'R': 285 pt = _fmt("%H:%M", t, pt, ptlim, warnp); 286 continue; 287 case 'r': 288 pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp); 289 continue; 290 case 'S': 291 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 292 continue; 293 case 's': 294 { 295 struct tm tm; 296 char buf[INT_STRLEN_MAXIMUM( 297 time_t) + 1]; 298 time_t mkt; 299 300 tm = *t; 301 mkt = mktime(&tm); 302 (void) snprintf(buf, sizeof buf, 303 "%ld", (long) mkt); 304 pt = _add(buf, pt, ptlim); 305 } 306 continue; 307 case 'T': 308 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 309 continue; 310 case 't': 311 pt = _add("\t", pt, ptlim); 312 continue; 313 case 'U': 314 pt = _conv((t->tm_yday + DAYSPERWEEK - 315 t->tm_wday) / DAYSPERWEEK, 316 "%02d", pt, ptlim); 317 continue; 318 case 'u': 319 /* 320 ** From Arnold Robbins' strftime version 3.0: 321 ** "ISO 8601: Weekday as a decimal number 322 ** [1 (Monday) - 7]" 323 ** (ado, 1993-05-24) 324 */ 325 pt = _conv((t->tm_wday == 0) ? 326 DAYSPERWEEK : t->tm_wday, 327 "%d", pt, ptlim); 328 continue; 329 case 'V': /* ISO 8601 week number */ 330 case 'G': /* ISO 8601 year (four digits) */ 331 case 'g': /* ISO 8601 year (two digits) */ 332 /* 333 ** From Arnold Robbins' strftime version 3.0: "the week number of the 334 ** year (the first Monday as the first day of week 1) as a decimal number 335 ** (01-53)." 336 ** (ado, 1993-05-24) 337 ** 338 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 339 ** "Week 01 of a year is per definition the first week which has the 340 ** Thursday in this year, which is equivalent to the week which contains 341 ** the fourth day of January. In other words, the first week of a new year 342 ** is the week which has the majority of its days in the new year. Week 01 343 ** might also contain days from the previous year and the week before week 344 ** 01 of a year is the last week (52 or 53) of the previous year even if 345 ** it contains days from the new year. A week starts with Monday (day 1) 346 ** and ends with Sunday (day 7). For example, the first week of the year 347 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 348 ** (ado, 1996-01-02) 349 */ 350 { 351 int year; 352 int base; 353 int yday; 354 int wday; 355 int w; 356 357 year = t->tm_year; 358 base = TM_YEAR_BASE; 359 yday = t->tm_yday; 360 wday = t->tm_wday; 361 for ( ; ; ) { 362 int len; 363 int bot; 364 int top; 365 366 len = isleap_sum(year, base) ? 367 DAYSPERLYEAR : 368 DAYSPERNYEAR; 369 /* 370 ** What yday (-3 ... 3) does 371 ** the ISO year begin on? 372 */ 373 bot = ((yday + 11 - wday) % 374 DAYSPERWEEK) - 3; 375 /* 376 ** What yday does the NEXT 377 ** ISO year begin on? 378 */ 379 top = bot - 380 (len % DAYSPERWEEK); 381 if (top < -3) 382 top += DAYSPERWEEK; 383 top += len; 384 if (yday >= top) { 385 ++base; 386 w = 1; 387 break; 388 } 389 if (yday >= bot) { 390 w = 1 + ((yday - bot) / 391 DAYSPERWEEK); 392 break; 393 } 394 --base; 395 yday += isleap_sum(year, base) ? 396 DAYSPERLYEAR : 397 DAYSPERNYEAR; 398 } 399 #ifdef XPG4_1994_04_09 400 if ((w == 52 && 401 t->tm_mon == TM_JANUARY) || 402 (w == 1 && 403 t->tm_mon == TM_DECEMBER)) 404 w = 53; 405 #endif /* defined XPG4_1994_04_09 */ 406 if (*format == 'V') 407 pt = _conv(w, "%02d", 408 pt, ptlim); 409 else if (*format == 'g') { 410 *warnp = IN_ALL; 411 pt = _yconv(year, base, 0, 1, 412 pt, ptlim); 413 } else pt = _yconv(year, base, 1, 1, 414 pt, ptlim); 415 } 416 continue; 417 case 'v': 418 /* 419 ** From Arnold Robbins' strftime version 3.0: 420 ** "date as dd-bbb-YYYY" 421 ** (ado, 1993-05-24) 422 */ 423 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp); 424 continue; 425 case 'W': 426 pt = _conv((t->tm_yday + DAYSPERWEEK - 427 (t->tm_wday ? 428 (t->tm_wday - 1) : 429 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 430 "%02d", pt, ptlim); 431 continue; 432 case 'w': 433 pt = _conv(t->tm_wday, "%d", pt, ptlim); 434 continue; 435 case 'X': 436 pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp); 437 continue; 438 case 'x': 439 { 440 int warn2 = IN_SOME; 441 442 pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2); 443 if (warn2 == IN_ALL) 444 warn2 = IN_THIS; 445 if (warn2 > *warnp) 446 *warnp = warn2; 447 } 448 continue; 449 case 'y': 450 *warnp = IN_ALL; 451 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 452 pt, ptlim); 453 continue; 454 case 'Y': 455 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 456 pt, ptlim); 457 continue; 458 case 'Z': 459 if (t->tm_zone != NULL) 460 pt = _add(t->tm_zone, pt, ptlim); 461 else if (t->tm_isdst >= 0) 462 pt = _add(tzname[t->tm_isdst != 0], 463 pt, ptlim); 464 /* 465 ** C99 says that %Z must be replaced by the 466 ** empty string if the time zone is not 467 ** determinable. 468 */ 469 continue; 470 case 'z': 471 { 472 int diff; 473 char const * sign; 474 475 if (t->tm_isdst < 0) 476 continue; 477 diff = t->tm_gmtoff; 478 if (diff < 0) { 479 sign = "-"; 480 diff = -diff; 481 } else sign = "+"; 482 pt = _add(sign, pt, ptlim); 483 diff /= SECSPERMIN; 484 diff = (diff / MINSPERHOUR) * 100 + 485 (diff % MINSPERHOUR); 486 pt = _conv(diff, "%04d", pt, ptlim); 487 } 488 continue; 489 case '+': 490 pt = _fmt(Locale->date_fmt, t, pt, ptlim, 491 warnp); 492 continue; 493 case '%': 494 /* 495 ** X311J/88-090 (4.12.3.5): if conversion char is 496 ** undefined, behavior is undefined. Print out the 497 ** character itself as printf(3) also does. 498 */ 499 default: 500 break; 501 } 502 } 503 if (pt == ptlim) 504 break; 505 *pt++ = *format; 506 } 507 return pt; 508 } 509 510 static char * 511 _conv(int n, const char *format, char *pt, const char *ptlim) 512 { 513 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 514 515 (void) snprintf(buf, sizeof buf, format, n); 516 return _add(buf, pt, ptlim); 517 } 518 519 static char * 520 _add(const char *str, char *pt, const char *ptlim) 521 { 522 while (pt < ptlim && (*pt = *str++) != '\0') 523 ++pt; 524 return pt; 525 } 526 527 /* 528 ** POSIX and the C Standard are unclear or inconsistent about 529 ** what %C and %y do if the year is negative or exceeds 9999. 530 ** Use the convention that %C concatenated with %y yields the 531 ** same output as %Y, and that %Y contains at least 4 bytes, 532 ** with more only if necessary. 533 */ 534 535 static char * 536 _yconv(int a, int b, int convert_top, int convert_yy, char *pt, const char *ptlim) 537 { 538 int lead; 539 int trail; 540 541 #define DIVISOR 100 542 trail = a % DIVISOR + b % DIVISOR; 543 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 544 trail %= DIVISOR; 545 if (trail < 0 && lead > 0) { 546 trail += DIVISOR; 547 --lead; 548 } else if (lead < 0 && trail > 0) { 549 trail -= DIVISOR; 550 ++lead; 551 } 552 if (convert_top) { 553 if (lead == 0 && trail < 0) 554 pt = _add("-0", pt, ptlim); 555 else pt = _conv(lead, "%02d", pt, ptlim); 556 } 557 if (convert_yy) 558 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 559 return pt; 560 } 561 562 #ifdef LOCALE_HOME 563 static struct lc_time_T * 564 _loc(void) 565 { 566 static const char locale_home[] = LOCALE_HOME; 567 static const char lc_time[] = "LC_TIME"; 568 static char * locale_buf; 569 570 int fd; 571 int oldsun; /* "...ain't got nothin' to do..." */ 572 int len; 573 char * lbuf; 574 char * nlbuf; 575 char * name; 576 char * p; 577 const char ** ap; 578 const char * plim; 579 char filename[PATH_MAX]; 580 struct stat st; 581 size_t namesize; 582 size_t bufsize; 583 584 /* 585 ** Use localebuf.mon[0] to signal whether locale is already set up. 586 */ 587 if (localebuf.mon[0]) 588 return &localebuf; 589 name = setlocale(LC_TIME, (char *) NULL); 590 if (name == NULL || *name == '\0') 591 goto no_locale; 592 /* 593 ** If the locale name is the same as our cache, use the cache. 594 */ 595 lbuf = locale_buf; 596 if (lbuf != NULL && strcmp(name, lbuf) == 0) { 597 p = lbuf; 598 for (ap = (const char **) &localebuf; 599 ap < (const char **) (&localebuf + 1); 600 ++ap) 601 *ap = p += strlen(p) + 1; 602 return &localebuf; 603 } 604 /* 605 ** Slurp the locale file into the cache. 606 */ 607 namesize = strlen(name) + 1; 608 if (sizeof filename < 609 ((sizeof locale_home) + namesize + (sizeof lc_time))) 610 goto no_locale; 611 oldsun = 0; 612 len = snprintf(filename, sizeof filename, "%s/%s/%s", locale_home, 613 name, lc_time); 614 if (len < 0 || len >= sizeof filename) 615 goto no_locale; 616 fd = open(filename, O_RDONLY); 617 if (fd == -1) { 618 /* 619 ** Old Sun systems have a different naming and data convention. 620 */ 621 oldsun = 1; 622 len = snprintf(filename, sizeof filename, "%s/%s/%s", 623 locale_home, lc_time, name); 624 if (len < 0 || len >= sizeof filename) 625 goto no_locale; 626 fd = open(filename, O_RDONLY); 627 if (fd == -1) 628 goto no_locale; 629 } 630 if (fstat(fd, &st) == -1) 631 goto bad_locale; 632 if (st.st_size <= 0) 633 goto bad_locale; 634 bufsize = namesize + st.st_size; 635 locale_buf = NULL; 636 nlbuf = realloc(lbuf, bufsize); 637 if (nlbuf == NULL) { 638 free(lbuf); 639 lbuf = NULL; 640 goto bad_locale; 641 } 642 lbuf = nlbuf; 643 (void) strlcpy(lbuf, name, bufsize); 644 p = lbuf + namesize; 645 plim = p + st.st_size; 646 if (read(fd, p, st.st_size) != st.st_size) 647 goto bad_lbuf; 648 if (close(fd) != 0) 649 goto bad_lbuf; 650 /* 651 ** Parse the locale file into localebuf. 652 */ 653 if (plim[-1] != '\n') 654 goto bad_lbuf; 655 for (ap = (const char **) &localebuf; 656 ap < (const char **) (&localebuf + 1); 657 ++ap) { 658 if (p == plim) 659 goto bad_lbuf; 660 *ap = p; 661 while (*p != '\n') 662 ++p; 663 *p++ = '\0'; 664 } 665 if (oldsun) { 666 /* 667 ** SunOS 4 used an obsolescent format; see localdtconv(3). 668 ** c_fmt had the ``short format for dates and times together'' 669 ** (SunOS 4 date, "%a %b %e %T %Z %Y" in the C locale); 670 ** date_fmt had the ``long format for dates'' 671 ** (SunOS 4 strftime %C, "%A, %B %e, %Y" in the C locale). 672 ** Discard the latter in favor of the former. 673 */ 674 localebuf.date_fmt = localebuf.c_fmt; 675 } 676 /* 677 ** Record the successful parse in the cache. 678 */ 679 locale_buf = lbuf; 680 681 return &localebuf; 682 683 bad_lbuf: 684 free(lbuf); 685 bad_locale: 686 (void) close(fd); 687 no_locale: 688 localebuf = C_time_locale; 689 locale_buf = NULL; 690 return &localebuf; 691 } 692 #endif /* defined LOCALE_HOME */ 693