lib/libc/stdtime/localtime.c

   1 /*
   2 ** This file is in the public domain, so clarified as of
   3 ** June 5, 1996 by Arthur David Olson (arthur_david_olson@nih.gov).
   4 **
   5 ** $FreeBSD: src/lib/libc/stdtime/localtime.c,v 1.25.2.2 2002/08/13 16:08:07 bmilekic Exp $
   6 ** $DragonFly: src/lib/libc/stdtime/localtime.c,v 1.4 2005/01/31 22:29:44 dillon Exp $
   7 */
   8
   9 /*
  10  * @(#)localtime.c      7.57
  11  */
  12 /*
  13 ** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
  14 ** POSIX-style TZ environment variable handling from Guy Harris
  15 ** (guy@auspex.com).
  16 */
  17
  18 /*LINTLIBRARY*/
  19
  20 #include "namespace.h"
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23
  24 #include <fcntl.h>
  25 #include <pthread.h>
  26 #include "private.h"
  27 #include <un-namespace.h>
  28
  29 #include "tzfile.h"
  30
  31 #include "libc_private.h"
  32
  33 #define _MUTEX_LOCK(x)          if (__isthreaded) _pthread_mutex_lock(x)
  34 #define _MUTEX_UNLOCK(x)        if (__isthreaded) _pthread_mutex_unlock(x)
  35
  36 /*
  37 ** SunOS 4.1.1 headers lack O_BINARY.
  38 */
  39
  40 #ifdef O_BINARY
  41 #define OPEN_MODE       (O_RDONLY | O_BINARY)
  42 #endif /* defined O_BINARY */
  43 #ifndef O_BINARY
  44 #define OPEN_MODE       O_RDONLY
  45 #endif /* !defined O_BINARY */
  46
  47 #ifndef WILDABBR
  48 /*
  49 ** Someone might make incorrect use of a time zone abbreviation:
  50 **      1.      They might reference tzname[0] before calling tzset (explicitly
  51 **              or implicitly).
  52 **      2.      They might reference tzname[1] before calling tzset (explicitly
  53 **              or implicitly).
  54 **      3.      They might reference tzname[1] after setting to a time zone
  55 **              in which Daylight Saving Time is never observed.
  56 **      4.      They might reference tzname[0] after setting to a time zone
  57 **              in which Standard Time is never observed.
  58 **      5.      They might reference tm.TM_ZONE after calling offtime.
  59 ** What's best to do in the above cases is open to debate;
  60 ** for now, we just set things up so that in any of the five cases
  61 ** WILDABBR is used.  Another possibility:  initialize tzname[0] to the
  62 ** string "tzname[0] used before set", and similarly for the other cases.
  63 ** And another:  initialize tzname[0] to "ERA", with an explanation in the
  64 ** manual page of what this "time zone abbreviation" means (doing this so
  65 ** that tzname[0] has the "normal" length of three characters).
  66 */
  67 #define WILDABBR        "   "
  68 #endif /* !defined WILDABBR */
  69
  70 static char             wildabbr[] = "WILDABBR";
  71
  72 static const char       gmt[] = "GMT";
  73
  74 struct ttinfo {                         /* time type information */
  75         long            tt_gmtoff;      /* GMT offset in seconds */
  76         int             tt_isdst;       /* used to set tm_isdst */
  77         int             tt_abbrind;     /* abbreviation list index */
  78         int             tt_ttisstd;     /* TRUE if transition is std time */
  79         int             tt_ttisgmt;     /* TRUE if transition is GMT */
  80 };
  81
  82 struct lsinfo {                         /* leap second information */
  83         time_t          ls_trans;       /* transition time */
  84         long            ls_corr;        /* correction to apply */
  85 };
  86
  87 #define BIGGEST(a, b)   (((a) > (b)) ? (a) : (b))
  88
  89 #ifdef TZNAME_MAX
  90 #define MY_TZNAME_MAX   TZNAME_MAX
  91 #endif /* defined TZNAME_MAX */
  92 #ifndef TZNAME_MAX
  93 #define MY_TZNAME_MAX   255
  94 #endif /* !defined TZNAME_MAX */
  95
  96 struct state {
  97         int             leapcnt;
  98         int             timecnt;
  99         int             typecnt;
 100         int             charcnt;
 101         time_t          ats[TZ_MAX_TIMES];
 102         unsigned char   types[TZ_MAX_TIMES];
 103         struct ttinfo   ttis[TZ_MAX_TYPES];
 104         char            chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
 105                                 (2 * (MY_TZNAME_MAX + 1)))];
 106         struct lsinfo   lsis[TZ_MAX_LEAPS];
 107 };
 108
 109 struct rule {
 110         int             r_type;         /* type of rule--see below */
 111         int             r_day;          /* day number of rule */
 112         int             r_week;         /* week number of rule */
 113         int             r_mon;          /* month number of rule */
 114         long            r_time;         /* transition time of rule */
 115 };
 116
 117 #define JULIAN_DAY              0       /* Jn - Julian day */
 118 #define DAY_OF_YEAR             1       /* n - day of year */
 119 #define MONTH_NTH_DAY_OF_WEEK   2       /* Mm.n.d - month, week, day of week */
 120
 121 /*
 122 ** Prototypes for static functions.
 123 */
 124
 125 static long             detzcode P((const char * codep));
 126 static const char *     getzname P((const char * strp));
 127 static const char *     getnum P((const char * strp, int * nump, int min,
 128                                 int max));
 129 static const char *     getsecs P((const char * strp, long * secsp));
 130 static const char *     getoffset P((const char * strp, long * offsetp));
 131 static const char *     getrule P((const char * strp, struct rule * rulep));
 132 static void             gmtload P((struct state * sp));
 133 static void             gmtsub P((const time_t * timep, long offset,
 134                                 struct tm * tmp));
 135 static void             localsub P((const time_t * timep, long offset,
 136                                 struct tm * tmp));
 137 static int              increment_overflow P((int * number, int delta));
 138 static int              normalize_overflow P((int * tensptr, int * unitsptr,
 139                                 int base));
 140 static void             settzname P((void));
 141 static time_t           time1 P((struct tm * tmp,
 142                                 void(*funcp) P((const time_t *,
 143                                 long, struct tm *)),
 144                                 long offset));
 145 static time_t           time2 P((struct tm *tmp,
 146                                 void(*funcp) P((const time_t *,
 147                                 long, struct tm*)),
 148                                 long offset, int * okayp));
 149 static void             timesub P((const time_t * timep, long offset,
 150                                 const struct state * sp, struct tm * tmp));
 151 static int              tmcomp P((const struct tm * atmp,
 152                                 const struct tm * btmp));
 153 static time_t           transtime P((time_t janfirst, int year,
 154                                 const struct rule * rulep, long offset));
 155 static int              tzload P((const char * name, struct state * sp));
 156 static int              tzparse P((const char * name, struct state * sp,
 157                                 int lastditch));
 158
 159 #ifdef ALL_STATE
 160 static struct state *   lclptr;
 161 static struct state *   gmtptr;
 162 #endif /* defined ALL_STATE */
 163
 164 #ifndef ALL_STATE
 165 static struct state     lclmem;
 166 static struct state     gmtmem;
 167 #define lclptr          (&lclmem)
 168 #define gmtptr          (&gmtmem)
 169 #endif /* State Farm */
 170
 171 #ifndef TZ_STRLEN_MAX
 172 #define TZ_STRLEN_MAX 255
 173 #endif /* !defined TZ_STRLEN_MAX */
 174
 175 static char             lcl_TZname[TZ_STRLEN_MAX + 1];
 176 static int              lcl_is_set;
 177 static int              gmt_is_set;
 178 static pthread_mutex_t  lcl_mutex = PTHREAD_MUTEX_INITIALIZER;
 179 static pthread_mutex_t  gmt_mutex = PTHREAD_MUTEX_INITIALIZER;
 180
 181 char *                  tzname[2] = {
 182         wildabbr,
 183         wildabbr
 184 };
 185
 186 /*
 187 ** Section 4.12.3 of X3.159-1989 requires that
 188 **      Except for the strftime function, these functions [asctime,
 189 **      ctime, gmtime, localtime] return values in one of two static
 190 **      objects: a broken-down time structure and an array of char.
 191 ** Thanks to Paul Eggert (eggert@twinsun.com) for noting this.
 192 */
 193
 194 static struct tm        tm;
 195
 196 #ifdef USG_COMPAT
 197 time_t                  timezone = 0;
 198 int                     daylight = 0;
 199 #endif /* defined USG_COMPAT */
 200
 201 #ifdef ALTZONE
 202 time_t                  altzone = 0;
 203 #endif /* defined ALTZONE */
 204
 205 static long
 206 detzcode(codep)
 207 const char * const      codep;
 208 {
 209         long    result;
 210         int     i;
 211
 212         result = (codep[0] & 0x80) ? ~0L : 0L;
 213         for (i = 0; i < 4; ++i)
 214                 result = (result << 8) | (codep[i] & 0xff);
 215         return result;
 216 }
 217
 218 static void
 219 settzname P((void))
 220 {
 221         struct state *  sp = lclptr;
 222         int                     i;
 223
 224         tzname[0] = wildabbr;
 225         tzname[1] = wildabbr;
 226 #ifdef USG_COMPAT
 227         daylight = 0;
 228         timezone = 0;
 229 #endif /* defined USG_COMPAT */
 230 #ifdef ALTZONE
 231         altzone = 0;
 232 #endif /* defined ALTZONE */
 233 #ifdef ALL_STATE
 234         if (sp == NULL) {
 235                 tzname[0] = tzname[1] = gmt;
 236                 return;
 237         }
 238 #endif /* defined ALL_STATE */
 239         for (i = 0; i < sp->typecnt; ++i) {
 240                 const struct ttinfo * const     ttisp = &sp->ttis[i];
 241
 242                 tzname[ttisp->tt_isdst] =
 243                         &sp->chars[ttisp->tt_abbrind];
 244 #ifdef USG_COMPAT
 245                 if (ttisp->tt_isdst)
 246                         daylight = 1;
 247                 if (i == 0 || !ttisp->tt_isdst)
 248                         timezone = -(ttisp->tt_gmtoff);
 249 #endif /* defined USG_COMPAT */
 250 #ifdef ALTZONE
 251                 if (i == 0 || ttisp->tt_isdst)
 252                         altzone = -(ttisp->tt_gmtoff);
 253 #endif /* defined ALTZONE */
 254         }
 255         /*
 256         ** And to get the latest zone names into tzname. . .
 257         */
 258         for (i = 0; i < sp->timecnt; ++i) {
 259                 const struct ttinfo * const     ttisp =
 260                                                         &sp->ttis[
 261                                                                 sp->types[i]];
 262
 263                 tzname[ttisp->tt_isdst] =
 264                         &sp->chars[ttisp->tt_abbrind];
 265         }
 266 }
 267
 268 static int
 269 tzload(name, sp)
 270 const char *            name;
 271 struct state * const    sp;
 272 {
 273         const char *    p;
 274         int             i;
 275         int             fid;
 276
 277         /* XXX The following is from OpenBSD, and I'm not sure it is correct */
 278         if (name != NULL && issetugid() != 0)
 279                 if ((name[0] == ':' && name[1] == '/') ||
 280                     name[0] == '/' || strchr(name, '.'))
 281                         name = NULL;
 282         if (name == NULL && (name = TZDEFAULT) == NULL)
 283                 return -1;
 284         {
 285                 int     doaccess;
 286                 struct stat     stab;
 287                 /*
 288                 ** Section 4.9.1 of the C standard says that
 289                 ** "FILENAME_MAX expands to an integral constant expression
 290                 ** that is the size needed for an array of char large enough
 291                 ** to hold the longest file name string that the implementation
 292                 ** guarantees can be opened."
 293                 */
 294                 char            fullname[FILENAME_MAX + 1];
 295
 296                 if (name[0] == ':')
 297                         ++name;
 298                 doaccess = name[0] == '/';
 299                 if (!doaccess) {
 300                         if ((p = TZDIR) == NULL)
 301                                 return -1;
 302                         if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
 303                                 return -1;
 304                         (void) strcpy(fullname, p);
 305                         (void) strcat(fullname, "/");
 306                         (void) strcat(fullname, name);
 307                         /*
 308                         ** Set doaccess if '.' (as in "../") shows up in name.
 309                         */
 310                         if (strchr(name, '.') != NULL)
 311                                 doaccess = TRUE;
 312                         name = fullname;
 313                 }
 314                 if (doaccess && access(name, R_OK) != 0)
 315                         return -1;
 316                 if ((fid = _open(name, OPEN_MODE)) == -1)
 317                         return -1;
 318                 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
 319                         _close(fid);
 320                         return -1;
 321                 }
 322         }
 323         {
 324                 struct tzhead * tzhp;
 325                 char            buf[sizeof *sp + sizeof *tzhp];
 326                 int             ttisstdcnt;
 327                 int             ttisgmtcnt;
 328
 329                 i = _read(fid, buf, sizeof buf);
 330                 if (_close(fid) != 0)
 331                         return -1;
 332                 p = buf;
 333                 p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
 334                 ttisstdcnt = (int) detzcode(p);
 335                 p += 4;
 336                 ttisgmtcnt = (int) detzcode(p);
 337                 p += 4;
 338                 sp->leapcnt = (int) detzcode(p);
 339                 p += 4;
 340                 sp->timecnt = (int) detzcode(p);
 341                 p += 4;
 342                 sp->typecnt = (int) detzcode(p);
 343                 p += 4;
 344                 sp->charcnt = (int) detzcode(p);
 345                 p += 4;
 346                 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
 347                         sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
 348                         sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
 349                         sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
 350                         (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
 351                         (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
 352                                 return -1;
 353                 if (i - (p - buf) < sp->timecnt * 4 +   /* ats */
 354                         sp->timecnt +                   /* types */
 355                         sp->typecnt * (4 + 2) +         /* ttinfos */
 356                         sp->charcnt +                   /* chars */
 357                         sp->leapcnt * (4 + 4) +         /* lsinfos */
 358                         ttisstdcnt +                    /* ttisstds */
 359                         ttisgmtcnt)                     /* ttisgmts */
 360                                 return -1;
 361                 for (i = 0; i < sp->timecnt; ++i) {
 362                         sp->ats[i] = detzcode(p);
 363                         p += 4;
 364                 }
 365                 for (i = 0; i < sp->timecnt; ++i) {
 366                         sp->types[i] = (unsigned char) *p++;
 367                         if (sp->types[i] >= sp->typecnt)
 368                                 return -1;
 369                 }
 370                 for (i = 0; i < sp->typecnt; ++i) {
 371                         struct ttinfo * ttisp;
 372
 373                         ttisp = &sp->ttis[i];
 374                         ttisp->tt_gmtoff = detzcode(p);
 375                         p += 4;
 376                         ttisp->tt_isdst = (unsigned char) *p++;
 377                         if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
 378                                 return -1;
 379                         ttisp->tt_abbrind = (unsigned char) *p++;
 380                         if (ttisp->tt_abbrind < 0 ||
 381                                 ttisp->tt_abbrind > sp->charcnt)
 382                                         return -1;
 383                 }
 384                 for (i = 0; i < sp->charcnt; ++i)
 385                         sp->chars[i] = *p++;
 386                 sp->chars[i] = '\0';    /* ensure '\0' at end */
 387                 for (i = 0; i < sp->leapcnt; ++i) {
 388                         struct lsinfo * lsisp;
 389
 390                         lsisp = &sp->lsis[i];
 391                         lsisp->ls_trans = detzcode(p);
 392                         p += 4;
 393                         lsisp->ls_corr = detzcode(p);
 394                         p += 4;
 395                 }
 396                 for (i = 0; i < sp->typecnt; ++i) {
 397                         struct ttinfo * ttisp;
 398
 399                         ttisp = &sp->ttis[i];
 400                         if (ttisstdcnt == 0)
 401                                 ttisp->tt_ttisstd = FALSE;
 402                         else {
 403                                 ttisp->tt_ttisstd = *p++;
 404                                 if (ttisp->tt_ttisstd != TRUE &&
 405                                         ttisp->tt_ttisstd != FALSE)
 406                                                 return -1;
 407                         }
 408                 }
 409                 for (i = 0; i < sp->typecnt; ++i) {
 410                         struct ttinfo * ttisp;
 411
 412                         ttisp = &sp->ttis[i];
 413                         if (ttisgmtcnt == 0)
 414                                 ttisp->tt_ttisgmt = FALSE;
 415                         else {
 416                                 ttisp->tt_ttisgmt = *p++;
 417                                 if (ttisp->tt_ttisgmt != TRUE &&
 418                                         ttisp->tt_ttisgmt != FALSE)
 419                                                 return -1;
 420                         }
 421                 }
 422         }
 423         return 0;
 424 }
 425
 426 static const int        mon_lengths[2][MONSPERYEAR] = {
 427         { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 428         { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 429 };
 430
 431 static const int        year_lengths[2] = {
 432         DAYSPERNYEAR, DAYSPERLYEAR
 433 };
 434
 435 /*
 436 ** Given a pointer into a time zone string, scan until a character that is not
 437 ** a valid character in a zone name is found.  Return a pointer to that
 438 ** character.
 439 */
 440
 441 static const char *
 442 getzname(strp)
 443 const char *    strp;
 444 {
 445         char    c;
 446
 447         while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
 448                 c != '+')
 449                         ++strp;
 450         return strp;
 451 }
 452
 453 /*
 454 ** Given a pointer into a time zone string, extract a number from that string.
 455 ** Check that the number is within a specified range; if it is not, return
 456 ** NULL.
 457 ** Otherwise, return a pointer to the first character not part of the number.
 458 */
 459
 460 static const char *
 461 getnum(strp, nump, min, max)
 462 const char *    strp;
 463 int * const             nump;
 464 const int               min;
 465 const int               max;
 466 {
 467         char    c;
 468         int     num;
 469
 470         if (strp == NULL || !is_digit(c = *strp))
 471                 return NULL;
 472         num = 0;
 473         do {
 474                 num = num * 10 + (c - '0');
 475                 if (num > max)
 476                         return NULL;    /* illegal value */
 477                 c = *++strp;
 478         } while (is_digit(c));
 479         if (num < min)
 480                 return NULL;            /* illegal value */
 481         *nump = num;
 482         return strp;
 483 }
 484
 485 /*
 486 ** Given a pointer into a time zone string, extract a number of seconds,
 487 ** in hh[:mm[:ss]] form, from the string.
 488 ** If any error occurs, return NULL.
 489 ** Otherwise, return a pointer to the first character not part of the number
 490 ** of seconds.
 491 */
 492
 493 static const char *
 494 getsecs(strp, secsp)
 495 const char *    strp;
 496 long * const            secsp;
 497 {
 498         int     num;
 499
 500         /*
 501         ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
 502         ** "M10.4.6/26", which does not conform to Posix,
 503         ** but which specifies the equivalent of
 504         ** ``02:00 on the first Sunday on or after 23 Oct''.
 505         */
 506         strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
 507         if (strp == NULL)
 508                 return NULL;
 509         *secsp = num * (long) SECSPERHOUR;
 510         if (*strp == ':') {
 511                 ++strp;
 512                 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
 513                 if (strp == NULL)
 514                         return NULL;
 515                 *secsp += num * SECSPERMIN;
 516                 if (*strp == ':') {
 517                         ++strp;
 518                         /* `SECSPERMIN' allows for leap seconds.  */
 519                         strp = getnum(strp, &num, 0, SECSPERMIN);
 520                         if (strp == NULL)
 521                                 return NULL;
 522                         *secsp += num;
 523                 }
 524         }
 525         return strp;
 526 }
 527
 528 /*
 529 ** Given a pointer into a time zone string, extract an offset, in
 530 ** [+-]hh[:mm[:ss]] form, from the string.
 531 ** If any error occurs, return NULL.
 532 ** Otherwise, return a pointer to the first character not part of the time.
 533 */
 534
 535 static const char *
 536 getoffset(strp, offsetp)
 537 const char *    strp;
 538 long * const            offsetp;
 539 {
 540         int     neg = 0;
 541
 542         if (*strp == '-') {
 543                 neg = 1;
 544                 ++strp;
 545         } else if (*strp == '+')
 546                 ++strp;
 547         strp = getsecs(strp, offsetp);
 548         if (strp == NULL)
 549                 return NULL;            /* illegal time */
 550         if (neg)
 551                 *offsetp = -*offsetp;
 552         return strp;
 553 }
 554
 555 /*
 556 ** Given a pointer into a time zone string, extract a rule in the form
 557 ** date[/time].  See POSIX section 8 for the format of "date" and "time".
 558 ** If a valid rule is not found, return NULL.
 559 ** Otherwise, return a pointer to the first character not part of the rule.
 560 */
 561
 562 static const char *
 563 getrule(strp, rulep)
 564 const char *                    strp;
 565 struct rule * const     rulep;
 566 {
 567         if (*strp == 'J') {
 568                 /*
 569                 ** Julian day.
 570                 */
 571                 rulep->r_type = JULIAN_DAY;
 572                 ++strp;
 573                 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
 574         } else if (*strp == 'M') {
 575                 /*
 576                 ** Month, week, day.
 577                 */
 578                 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
 579                 ++strp;
 580                 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
 581                 if (strp == NULL)
 582                         return NULL;
 583                 if (*strp++ != '.')
 584                         return NULL;
 585                 strp = getnum(strp, &rulep->r_week, 1, 5);
 586                 if (strp == NULL)
 587                         return NULL;
 588                 if (*strp++ != '.')
 589                         return NULL;
 590                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
 591         } else if (is_digit(*strp)) {
 592                 /*
 593                 ** Day of year.
 594                 */
 595                 rulep->r_type = DAY_OF_YEAR;
 596                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
 597         } else  return NULL;            /* invalid format */
 598         if (strp == NULL)
 599                 return NULL;
 600         if (*strp == '/') {
 601                 /*
 602                 ** Time specified.
 603                 */
 604                 ++strp;
 605                 strp = getsecs(strp, &rulep->r_time);
 606         } else  rulep->r_time = 2 * SECSPERHOUR;        /* default = 2:00:00 */
 607         return strp;
 608 }
 609
 610 /*
 611 ** Given the Epoch-relative time of January 1, 00:00:00 GMT, in a year, the
 612 ** year, a rule, and the offset from GMT at the time that rule takes effect,
 613 ** calculate the Epoch-relative time that rule takes effect.
 614 */
 615
 616 static time_t
 617 transtime(janfirst, year, rulep, offset)
 618 const time_t                            janfirst;
 619 const int                               year;
 620 const struct rule * const       rulep;
 621 const long                              offset;
 622 {
 623         int     leapyear;
 624         time_t  value;
 625         int     i;
 626         int             d, m1, yy0, yy1, yy2, dow;
 627
 628         INITIALIZE(value);
 629         leapyear = isleap(year);
 630         switch (rulep->r_type) {
 631
 632         case JULIAN_DAY:
 633                 /*
 634                 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
 635                 ** years.
 636                 ** In non-leap years, or if the day number is 59 or less, just
 637                 ** add SECSPERDAY times the day number-1 to the time of
 638                 ** January 1, midnight, to get the day.
 639                 */
 640                 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
 641                 if (leapyear && rulep->r_day >= 60)
 642                         value += SECSPERDAY;
 643                 break;
 644
 645         case DAY_OF_YEAR:
 646                 /*
 647                 ** n - day of year.
 648                 ** Just add SECSPERDAY times the day number to the time of
 649                 ** January 1, midnight, to get the day.
 650                 */
 651                 value = janfirst + rulep->r_day * SECSPERDAY;
 652                 break;
 653
 654         case MONTH_NTH_DAY_OF_WEEK:
 655                 /*
 656                 ** Mm.n.d - nth "dth day" of month m.
 657                 */
 658                 value = janfirst;
 659                 for (i = 0; i < rulep->r_mon - 1; ++i)
 660                         value += mon_lengths[leapyear][i] * SECSPERDAY;
 661
 662                 /*
 663                 ** Use Zeller's Congruence to get day-of-week of first day of
 664                 ** month.
 665                 */
 666                 m1 = (rulep->r_mon + 9) % 12 + 1;
 667                 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
 668                 yy1 = yy0 / 100;
 669                 yy2 = yy0 % 100;
 670                 dow = ((26 * m1 - 2) / 10 +
 671                         1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
 672                 if (dow < 0)
 673                         dow += DAYSPERWEEK;
 674
 675                 /*
 676                 ** "dow" is the day-of-week of the first day of the month.  Get
 677                 ** the day-of-month (zero-origin) of the first "dow" day of the
 678                 ** month.
 679                 */
 680                 d = rulep->r_day - dow;
 681                 if (d < 0)
 682                         d += DAYSPERWEEK;
 683                 for (i = 1; i < rulep->r_week; ++i) {
 684                         if (d + DAYSPERWEEK >=
 685                                 mon_lengths[leapyear][rulep->r_mon - 1])
 686                                         break;
 687                         d += DAYSPERWEEK;
 688                 }
 689
 690                 /*
 691                 ** "d" is the day-of-month (zero-origin) of the day we want.
 692                 */
 693                 value += d * SECSPERDAY;
 694                 break;
 695         }
 696
 697         /*
 698         ** "value" is the Epoch-relative time of 00:00:00 GMT on the day in
 699         ** question.  To get the Epoch-relative time of the specified local
 700         ** time on that day, add the transition time and the current offset
 701         ** from GMT.
 702         */
 703         return value + rulep->r_time + offset;
 704 }
 705
 706 /*
 707 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
 708 ** appropriate.
 709 */
 710
 711 static int
 712 tzparse(name, sp, lastditch)
 713 const char *                    name;
 714 struct state * const    sp;
 715 const int                       lastditch;
 716 {
 717         const char *                    stdname;
 718         const char *                    dstname;
 719         size_t                          stdlen;
 720         size_t                          dstlen;
 721         long                            stdoffset;
 722         long                            dstoffset;
 723         time_t *                atp;
 724         unsigned char * typep;
 725         char *                  cp;
 726         int                     load_result;
 727
 728         INITIALIZE(dstname);
 729         stdname = name;
 730         if (lastditch) {
 731                 stdlen = strlen(name);  /* length of standard zone name */
 732                 name += stdlen;
 733                 if (stdlen >= sizeof sp->chars)
 734                         stdlen = (sizeof sp->chars) - 1;
 735                 stdoffset = 0;
 736         } else {
 737                 name = getzname(name);
 738                 stdlen = name - stdname;
 739                 if (stdlen < 3)
 740                         return -1;
 741                 if (*name == '\0')
 742                         return -1;      /* was "stdoffset = 0;" */
 743                 else {
 744                         name = getoffset(name, &stdoffset);
 745                         if (name == NULL)
 746                                 return -1;
 747                 }
 748         }
 749         load_result = tzload(TZDEFRULES, sp);
 750         if (load_result != 0)
 751                 sp->leapcnt = 0;                /* so, we're off a little */
 752         if (*name != '\0') {
 753                 dstname = name;
 754                 name = getzname(name);
 755                 dstlen = name - dstname;        /* length of DST zone name */
 756                 if (dstlen < 3)
 757                         return -1;
 758                 if (*name != '\0' && *name != ',' && *name != ';') {
 759                         name = getoffset(name, &dstoffset);
 760                         if (name == NULL)
 761                                 return -1;
 762                 } else  dstoffset = stdoffset - SECSPERHOUR;
 763                 if (*name == ',' || *name == ';') {
 764                         struct rule     start;
 765                         struct rule     end;
 766                         int     year;
 767                         time_t  janfirst;
 768                         time_t          starttime;
 769                         time_t          endtime;
 770
 771                         ++name;
 772                         if ((name = getrule(name, &start)) == NULL)
 773                                 return -1;
 774                         if (*name++ != ',')
 775                                 return -1;
 776                         if ((name = getrule(name, &end)) == NULL)
 777                                 return -1;
 778                         if (*name != '\0')
 779                                 return -1;
 780                         sp->typecnt = 2;        /* standard time and DST */
 781                         /*
 782                         ** Two transitions per year, from EPOCH_YEAR to 2037.
 783                         */
 784                         sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
 785                         if (sp->timecnt > TZ_MAX_TIMES)
 786                                 return -1;
 787                         sp->ttis[0].tt_gmtoff = -dstoffset;
 788                         sp->ttis[0].tt_isdst = 1;
 789                         sp->ttis[0].tt_abbrind = stdlen + 1;
 790                         sp->ttis[1].tt_gmtoff = -stdoffset;
 791                         sp->ttis[1].tt_isdst = 0;
 792                         sp->ttis[1].tt_abbrind = 0;
 793                         atp = sp->ats;
 794                         typep = sp->types;
 795                         janfirst = 0;
 796                         for (year = EPOCH_YEAR; year <= 2037; ++year) {
 797                                 starttime = transtime(janfirst, year, &start,
 798                                         stdoffset);
 799                                 endtime = transtime(janfirst, year, &end,
 800                                         dstoffset);
 801                                 if (starttime > endtime) {
 802                                         *atp++ = endtime;
 803                                         *typep++ = 1;   /* DST ends */
 804                                         *atp++ = starttime;
 805                                         *typep++ = 0;   /* DST begins */
 806                                 } else {
 807                                         *atp++ = starttime;
 808                                         *typep++ = 0;   /* DST begins */
 809                                         *atp++ = endtime;
 810                                         *typep++ = 1;   /* DST ends */
 811                                 }
 812                                 janfirst += year_lengths[isleap(year)] *
 813                                         SECSPERDAY;
 814                         }
 815                 } else {
 816                         long    theirstdoffset;
 817                         long    theirdstoffset;
 818                         long    theiroffset;
 819                         int     isdst;
 820                         int     i;
 821                         int     j;
 822
 823                         if (*name != '\0')
 824                                 return -1;
 825                         if (load_result != 0)
 826                                 return -1;
 827                         /*
 828                         ** Initial values of theirstdoffset and theirdstoffset.
 829                         */
 830                         theirstdoffset = 0;
 831                         for (i = 0; i < sp->timecnt; ++i) {
 832                                 j = sp->types[i];
 833                                 if (!sp->ttis[j].tt_isdst) {
 834                                         theirstdoffset =
 835                                                 -sp->ttis[j].tt_gmtoff;
 836                                         break;
 837                                 }
 838                         }
 839                         theirdstoffset = 0;
 840                         for (i = 0; i < sp->timecnt; ++i) {
 841                                 j = sp->types[i];
 842                                 if (sp->ttis[j].tt_isdst) {
 843                                         theirdstoffset =
 844                                                 -sp->ttis[j].tt_gmtoff;
 845                                         break;
 846                                 }
 847                         }
 848                         /*
 849                         ** Initially we're assumed to be in standard time.
 850                         */
 851                         isdst = FALSE;
 852                         theiroffset = theirstdoffset;
 853                         /*
 854                         ** Now juggle transition times and types
 855                         ** tracking offsets as you do.
 856                         */
 857                         for (i = 0; i < sp->timecnt; ++i) {
 858                                 j = sp->types[i];
 859                                 sp->types[i] = sp->ttis[j].tt_isdst;
 860                                 if (sp->ttis[j].tt_ttisgmt) {
 861                                         /* No adjustment to transition time */
 862                                 } else {
 863                                         /*
 864                                         ** If summer time is in effect, and the
 865                                         ** transition time was not specified as
 866                                         ** standard time, add the summer time
 867                                         ** offset to the transition time;
 868                                         ** otherwise, add the standard time
 869                                         ** offset to the transition time.
 870                                         */
 871                                         /*
 872                                         ** Transitions from DST to DDST
 873                                         ** will effectively disappear since
 874                                         ** POSIX provides for only one DST
 875                                         ** offset.
 876                                         */
 877                                         if (isdst && !sp->ttis[j].tt_ttisstd) {
 878                                                 sp->ats[i] += dstoffset -
 879                                                         theirdstoffset;
 880                                         } else {
 881                                                 sp->ats[i] += stdoffset -
 882                                                         theirstdoffset;
 883                                         }
 884                                 }
 885                                 theiroffset = -sp->ttis[j].tt_gmtoff;
 886                                 if (sp->ttis[j].tt_isdst)
 887                                         theirdstoffset = theiroffset;
 888                                 else    theirstdoffset = theiroffset;
 889                         }
 890                         /*
 891                         ** Finally, fill in ttis.
 892                         ** ttisstd and ttisgmt need not be handled.
 893                         */
 894                         sp->ttis[0].tt_gmtoff = -stdoffset;
 895                         sp->ttis[0].tt_isdst = FALSE;
 896                         sp->ttis[0].tt_abbrind = 0;
 897                         sp->ttis[1].tt_gmtoff = -dstoffset;
 898                         sp->ttis[1].tt_isdst = TRUE;
 899                         sp->ttis[1].tt_abbrind = stdlen + 1;
 900                 }
 901         } else {
 902                 dstlen = 0;
 903                 sp->typecnt = 1;                /* only standard time */
 904                 sp->timecnt = 0;
 905                 sp->ttis[0].tt_gmtoff = -stdoffset;
 906                 sp->ttis[0].tt_isdst = 0;
 907                 sp->ttis[0].tt_abbrind = 0;
 908         }
 909         sp->charcnt = stdlen + 1;
 910         if (dstlen != 0)
 911                 sp->charcnt += dstlen + 1;
 912         if (sp->charcnt > sizeof sp->chars)
 913                 return -1;
 914         cp = sp->chars;
 915         (void) strncpy(cp, stdname, stdlen);
 916         cp += stdlen;
 917         *cp++ = '\0';
 918         if (dstlen != 0) {
 919                 (void) strncpy(cp, dstname, dstlen);
 920                 *(cp + dstlen) = '\0';
 921         }
 922         return 0;
 923 }
 924
 925 static void
 926 gmtload(sp)
 927 struct state * const    sp;
 928 {
 929         if (tzload(gmt, sp) != 0)
 930                 (void) tzparse(gmt, sp, TRUE);
 931 }
 932
 933 static void
 934 tzsetwall_basic(void)
 935 {
 936         if (lcl_is_set < 0)
 937                 return;
 938         lcl_is_set = -1;
 939
 940 #ifdef ALL_STATE
 941         if (lclptr == NULL) {
 942                 lclptr = (struct state *) malloc(sizeof *lclptr);
 943                 if (lclptr == NULL) {
 944                         settzname();    /* all we can do */
 945                         return;
 946                 }
 947         }
 948 #endif /* defined ALL_STATE */
 949         if (tzload((char *) NULL, lclptr) != 0)
 950                 gmtload(lclptr);
 951         settzname();
 952 }
 953
 954 void
 955 tzsetwall P((void))
 956 {
 957         _MUTEX_LOCK(&lcl_mutex);
 958         tzsetwall_basic();
 959         _MUTEX_UNLOCK(&lcl_mutex);
 960 }
 961
 962 static void
 963 tzset_basic (void)
 964 {
 965         const char *    name;
 966
 967         name = getenv("TZ");
 968         if (name == NULL) {
 969                 tzsetwall();
 970                 return;
 971         }
 972
 973         if (lcl_is_set > 0  &&  strcmp(lcl_TZname, name) == 0)
 974                 return;
 975         lcl_is_set = (strlen(name) < sizeof(lcl_TZname));
 976         if (lcl_is_set)
 977                 (void) strcpy(lcl_TZname, name);
 978
 979 #ifdef ALL_STATE
 980         if (lclptr == NULL) {
 981                 lclptr = (struct state *) malloc(sizeof *lclptr);
 982                 if (lclptr == NULL) {
 983                         settzname();    /* all we can do */
 984                         return;
 985                 }
 986         }
 987 #endif /* defined ALL_STATE */
 988         if (*name == '\0') {
 989                 /*
 990                 ** User wants it fast rather than right.
 991                 */
 992                 lclptr->leapcnt = 0;            /* so, we're off a little */
 993                 lclptr->timecnt = 0;
 994                 lclptr->ttis[0].tt_gmtoff = 0;
 995                 lclptr->ttis[0].tt_abbrind = 0;
 996                 (void) strcpy(lclptr->chars, gmt);
 997         } else if (tzload(name, lclptr) != 0)
 998                 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
 999                         (void) gmtload(lclptr);
1000         settzname();
1001 }
1002
1003 void
1004 tzset(void)
1005 {
1006         _MUTEX_LOCK(&lcl_mutex);
1007         tzset_basic();
1008         _MUTEX_UNLOCK(&lcl_mutex);
1009 }
1010
1011 /*
1012 ** The easy way to behave "as if no library function calls" localtime
1013 ** is to not call it--so we drop its guts into "localsub", which can be
1014 ** freely called.  (And no, the PANS doesn't require the above behavior--
1015 ** but it *is* desirable.)
1016 **
1017 ** The unused offset argument is for the benefit of mktime variants.
1018 */
1019
1020 /*ARGSUSED*/
1021 static void
1022 localsub(timep, offset, tmp)
1023 const time_t * const    timep;
1024 const long              offset;
1025 struct tm * const       tmp;
1026 {
1027         struct state *          sp;
1028         const struct ttinfo *   ttisp;
1029         int                     i;
1030         const time_t                    t = *timep;
1031
1032         sp = lclptr;
1033 #ifdef ALL_STATE
1034         if (sp == NULL) {
1035                 gmtsub(timep, offset, tmp);
1036                 return;
1037         }
1038 #endif /* defined ALL_STATE */
1039         if (sp->timecnt == 0 || t < sp->ats[0]) {
1040                 i = 0;
1041                 while (sp->ttis[i].tt_isdst)
1042                         if (++i >= sp->typecnt) {
1043                                 i = 0;
1044                                 break;
1045                         }
1046         } else {
1047                 for (i = 1; i < sp->timecnt; ++i)
1048                         if (t < sp->ats[i])
1049                                 break;
1050                 i = sp->types[i - 1];
1051         }
1052         ttisp = &sp->ttis[i];
1053         /*
1054         ** To get (wrong) behavior that's compatible with System V Release 2.0
1055         ** you'd replace the statement below with
1056         **      t += ttisp->tt_gmtoff;
1057         **      timesub(&t, 0L, sp, tmp);
1058         */
1059         timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1060         tmp->tm_isdst = ttisp->tt_isdst;
1061         tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1062 #ifdef TM_ZONE
1063         tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1064 #endif /* defined TM_ZONE */
1065 }
1066
1067 struct tm *
1068 localtime_r(timep, p_tm)
1069 const time_t * const    timep;
1070 struct tm *p_tm;
1071 {
1072         _MUTEX_LOCK(&lcl_mutex);
1073         tzset();
1074         localsub(timep, 0L, p_tm);
1075         _MUTEX_UNLOCK(&lcl_mutex);
1076         return(p_tm);
1077 }
1078
1079 struct tm *
1080 localtime(timep)
1081 const time_t * const    timep;
1082 {
1083         static pthread_mutex_t localtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1084         static pthread_key_t localtime_key = -1;
1085         struct tm *p_tm;
1086
1087         if (__isthreaded != 0) {
1088                 _pthread_mutex_lock(&localtime_mutex);
1089                 if (localtime_key < 0) {
1090                         if (_pthread_key_create(&localtime_key, free) < 0) {
1091                                 _pthread_mutex_unlock(&localtime_mutex);
1092                                 return(NULL);
1093                         }
1094                 }
1095                 _pthread_mutex_unlock(&localtime_mutex);
1096                 p_tm = _pthread_getspecific(localtime_key);
1097                 if (p_tm == NULL) {
1098                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1099                             == NULL)
1100                                 return(NULL);
1101                         _pthread_setspecific(localtime_key, p_tm);
1102                 }
1103                 _pthread_mutex_lock(&lcl_mutex);
1104                 tzset();
1105                 localsub(timep, 0L, p_tm);
1106                 _pthread_mutex_unlock(&lcl_mutex);
1107                 return(p_tm);
1108         } else {
1109                 tzset();
1110                 localsub(timep, 0L, &tm);
1111                 return(&tm);
1112         }
1113 }
1114
1115 /*
1116 ** gmtsub is to gmtime as localsub is to localtime.
1117 */
1118
1119 static void
1120 gmtsub(timep, offset, tmp)
1121 const time_t * const    timep;
1122 const long              offset;
1123 struct tm * const       tmp;
1124 {
1125         _MUTEX_LOCK(&gmt_mutex);
1126         if (!gmt_is_set) {
1127                 gmt_is_set = TRUE;
1128 #ifdef ALL_STATE
1129                 gmtptr = (struct state *) malloc(sizeof *gmtptr);
1130                 if (gmtptr != NULL)
1131 #endif /* defined ALL_STATE */
1132                         gmtload(gmtptr);
1133         }
1134         _MUTEX_UNLOCK(&gmt_mutex);
1135         timesub(timep, offset, gmtptr, tmp);
1136 #ifdef TM_ZONE
1137         /*
1138         ** Could get fancy here and deliver something such as
1139         ** "GMT+xxxx" or "GMT-xxxx" if offset is non-zero,
1140         ** but this is no time for a treasure hunt.
1141         */
1142         if (offset != 0)
1143                 tmp->TM_ZONE = wildabbr;
1144         else {
1145 #ifdef ALL_STATE
1146                 if (gmtptr == NULL)
1147                         tmp->TM_ZONE = gmt;
1148                 else    tmp->TM_ZONE = gmtptr->chars;
1149 #endif /* defined ALL_STATE */
1150 #ifndef ALL_STATE
1151                 tmp->TM_ZONE = gmtptr->chars;
1152 #endif /* State Farm */
1153         }
1154 #endif /* defined TM_ZONE */
1155 }
1156
1157 struct tm *
1158 gmtime(timep)
1159 const time_t * const    timep;
1160 {
1161         static pthread_mutex_t gmtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1162         static pthread_key_t gmtime_key = -1;
1163         struct tm *p_tm;
1164
1165         if (__isthreaded != 0) {
1166                 _pthread_mutex_lock(&gmtime_mutex);
1167                 if (gmtime_key < 0) {
1168                         if (_pthread_key_create(&gmtime_key, free) < 0) {
1169                                 _pthread_mutex_unlock(&gmtime_mutex);
1170                                 return(NULL);
1171                 }
1172         }
1173         _pthread_mutex_unlock(&gmtime_mutex);
1174                 /*
1175                  * Changed to follow POSIX.1 threads standard, which
1176                  * is what BSD currently has.
1177                  */
1178                 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1179                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1180                             == NULL) {
1181                                 return(NULL);
1182                         }
1183                         _pthread_setspecific(gmtime_key, p_tm);
1184                 }
1185                 gmtsub(timep, 0L, p_tm);
1186                 return(p_tm);
1187         }
1188         else {
1189                 gmtsub(timep, 0L, &tm);
1190                 return(&tm);
1191         }
1192 }
1193
1194 struct tm *
1195 gmtime_r(const time_t * timep, struct tm * tm)
1196 {
1197         gmtsub(timep, 0L, tm);
1198         return(tm);
1199 }
1200
1201 #ifdef STD_INSPIRED
1202
1203 struct tm *
1204 offtime(timep, offset)
1205 const time_t * const    timep;
1206 const long              offset;
1207 {
1208         gmtsub(timep, offset, &tm);
1209         return &tm;
1210 }
1211
1212 #endif /* defined STD_INSPIRED */
1213
1214 static void
1215 timesub(timep, offset, sp, tmp)
1216 const time_t * const                    timep;
1217 const long                              offset;
1218 const struct state * const      sp;
1219 struct tm * const               tmp;
1220 {
1221         const struct lsinfo *   lp;
1222         long                    days;
1223         long                    rem;
1224         int                     y;
1225         int                     yleap;
1226         const int *             ip;
1227         long                    corr;
1228         int                     hit;
1229         int                     i;
1230
1231         corr = 0;
1232         hit = 0;
1233 #ifdef ALL_STATE
1234         i = (sp == NULL) ? 0 : sp->leapcnt;
1235 #endif /* defined ALL_STATE */
1236 #ifndef ALL_STATE
1237         i = sp->leapcnt;
1238 #endif /* State Farm */
1239         while (--i >= 0) {
1240                 lp = &sp->lsis[i];
1241                 if (*timep >= lp->ls_trans) {
1242                         if (*timep == lp->ls_trans) {
1243                                 hit = ((i == 0 && lp->ls_corr > 0) ||
1244                                         lp->ls_corr > sp->lsis[i - 1].ls_corr);
1245                                 if (hit)
1246                                         while (i > 0 &&
1247                                                 sp->lsis[i].ls_trans ==
1248                                                 sp->lsis[i - 1].ls_trans + 1 &&
1249                                                 sp->lsis[i].ls_corr ==
1250                                                 sp->lsis[i - 1].ls_corr + 1) {
1251                                                         ++hit;
1252                                                         --i;
1253                                         }
1254                         }
1255                         corr = lp->ls_corr;
1256                         break;
1257                 }
1258         }
1259         days = *timep / SECSPERDAY;
1260         rem = *timep % SECSPERDAY;
1261 #ifdef mc68k
1262         if (*timep == 0x80000000) {
1263                 /*
1264                 ** A 3B1 muffs the division on the most negative number.
1265                 */
1266                 days = -24855;
1267                 rem = -11648;
1268         }
1269 #endif /* defined mc68k */
1270         rem += (offset - corr);
1271         while (rem < 0) {
1272                 rem += SECSPERDAY;
1273                 --days;
1274         }
1275         while (rem >= SECSPERDAY) {
1276                 rem -= SECSPERDAY;
1277                 ++days;
1278         }
1279         tmp->tm_hour = (int) (rem / SECSPERHOUR);
1280         rem = rem % SECSPERHOUR;
1281         tmp->tm_min = (int) (rem / SECSPERMIN);
1282         /*
1283         ** A positive leap second requires a special
1284         ** representation.  This uses "... ??:59:60" et seq.
1285         */
1286         tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1287         tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
1288         if (tmp->tm_wday < 0)
1289                 tmp->tm_wday += DAYSPERWEEK;
1290         y = EPOCH_YEAR;
1291 #define LEAPS_THRU_END_OF(y)    ((y) / 4 - (y) / 100 + (y) / 400)
1292         while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
1293                 int     newy;
1294
1295                 newy = y + days / DAYSPERNYEAR;
1296                 if (days < 0)
1297                         --newy;
1298                 days -= (newy - y) * DAYSPERNYEAR +
1299                         LEAPS_THRU_END_OF(newy - 1) -
1300                         LEAPS_THRU_END_OF(y - 1);
1301                 y = newy;
1302         }
1303         tmp->tm_year = y - TM_YEAR_BASE;
1304         tmp->tm_yday = (int) days;
1305         ip = mon_lengths[yleap];
1306         for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
1307                 days = days - (long) ip[tmp->tm_mon];
1308         tmp->tm_mday = (int) (days + 1);
1309         tmp->tm_isdst = 0;
1310 #ifdef TM_GMTOFF
1311         tmp->TM_GMTOFF = offset;
1312 #endif /* defined TM_GMTOFF */
1313 }
1314
1315 char *
1316 ctime(timep)
1317 const time_t * const    timep;
1318 {
1319 /*
1320 ** Section 4.12.3.2 of X3.159-1989 requires that
1321 **      The ctime funciton converts the calendar time pointed to by timer
1322 **      to local time in the form of a string.  It is equivalent to
1323 **              asctime(localtime(timer))
1324 */
1325         return asctime(localtime(timep));
1326 }
1327
1328 char *
1329 ctime_r(timep, buf)
1330 const time_t * const    timep;
1331 char *buf;
1332 {
1333         struct tm tm;
1334         return asctime_r(localtime_r(timep, &tm), buf);
1335 }
1336
1337 /*
1338 ** Adapted from code provided by Robert Elz, who writes:
1339 **      The "best" way to do mktime I think is based on an idea of Bob
1340 **      Kridle's (so its said...) from a long time ago.
1341 **      [kridle@xinet.com as of 1996-01-16.]
1342 **      It does a binary search of the time_t space.  Since time_t's are
1343 **      just 32 bits, its a max of 32 iterations (even at 64 bits it
1344 **      would still be very reasonable).
1345 */
1346
1347 #ifndef WRONG
1348 #define WRONG   (-1)
1349 #endif /* !defined WRONG */
1350
1351 /*
1352 ** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
1353 */
1354
1355 static int
1356 increment_overflow(number, delta)
1357 int *   number;
1358 int     delta;
1359 {
1360         int     number0;
1361
1362         number0 = *number;
1363         *number += delta;
1364         return (*number < number0) != (delta < 0);
1365 }
1366
1367 static int
1368 normalize_overflow(tensptr, unitsptr, base)
1369 int * const     tensptr;
1370 int * const     unitsptr;
1371 const int       base;
1372 {
1373         int     tensdelta;
1374
1375         tensdelta = (*unitsptr >= 0) ?
1376                 (*unitsptr / base) :
1377                 (-1 - (-1 - *unitsptr) / base);
1378         *unitsptr -= tensdelta * base;
1379         return increment_overflow(tensptr, tensdelta);
1380 }
1381
1382 static int
1383 tmcomp(atmp, btmp)
1384 const struct tm * const atmp;
1385 const struct tm * const btmp;
1386 {
1387         int     result;
1388
1389         if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1390                 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1391                 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1392                 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1393                 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1394                         result = atmp->tm_sec - btmp->tm_sec;
1395         return result;
1396 }
1397
1398 static time_t
1399 time2(tmp, funcp, offset, okayp)
1400 struct tm * const       tmp;
1401 void (* const           funcp) P((const time_t*, long, struct tm*));
1402 const long              offset;
1403 int * const             okayp;
1404 {
1405         const struct state *    sp;
1406         int                     dir;
1407         int                     bits;
1408         int                     i, j ;
1409         int                     saved_seconds;
1410         time_t                          newt;
1411         time_t                          t;
1412         struct tm                       yourtm, mytm;
1413
1414         *okayp = FALSE;
1415         yourtm = *tmp;
1416         if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1417                 return WRONG;
1418         if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1419                 return WRONG;
1420         if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
1421                 return WRONG;
1422         /*
1423         ** Turn yourtm.tm_year into an actual year number for now.
1424         ** It is converted back to an offset from TM_YEAR_BASE later.
1425         */
1426         if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
1427                 return WRONG;
1428         while (yourtm.tm_mday <= 0) {
1429                 if (increment_overflow(&yourtm.tm_year, -1))
1430                         return WRONG;
1431                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1432                 yourtm.tm_mday += year_lengths[isleap(i)];
1433         }
1434         while (yourtm.tm_mday > DAYSPERLYEAR) {
1435                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1436                 yourtm.tm_mday -= year_lengths[isleap(i)];
1437                 if (increment_overflow(&yourtm.tm_year, 1))
1438                         return WRONG;
1439         }
1440         for ( ; ; ) {
1441                 i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
1442                 if (yourtm.tm_mday <= i)
1443                         break;
1444                 yourtm.tm_mday -= i;
1445                 if (++yourtm.tm_mon >= MONSPERYEAR) {
1446                         yourtm.tm_mon = 0;
1447                         if (increment_overflow(&yourtm.tm_year, 1))
1448                                 return WRONG;
1449                 }
1450         }
1451         if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
1452                 return WRONG;
1453         if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
1454                 /*
1455                 ** We can't set tm_sec to 0, because that might push the
1456                 ** time below the minimum representable time.
1457                 ** Set tm_sec to 59 instead.
1458                 ** This assumes that the minimum representable time is
1459                 ** not in the same minute that a leap second was deleted from,
1460                 ** which is a safer assumption than using 58 would be.
1461                 */
1462                 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1463                         return WRONG;
1464                 saved_seconds = yourtm.tm_sec;
1465                 yourtm.tm_sec = SECSPERMIN - 1;
1466         } else {
1467                 saved_seconds = yourtm.tm_sec;
1468                 yourtm.tm_sec = 0;
1469         }
1470         /*
1471         ** Divide the search space in half
1472         ** (this works whether time_t is signed or unsigned).
1473         */
1474         bits = TYPE_BIT(time_t) - 1;
1475         /*
1476         ** If time_t is signed, then 0 is just above the median,
1477         ** assuming two's complement arithmetic.
1478         ** If time_t is unsigned, then (1 << bits) is just above the median.
1479         */
1480         t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
1481         for ( ; ; ) {
1482                 (*funcp)(&t, offset, &mytm);
1483                 dir = tmcomp(&mytm, &yourtm);
1484                 if (dir != 0) {
1485                         if (bits-- < 0)
1486                                 return WRONG;
1487                         if (bits < 0)
1488                                 --t; /* may be needed if new t is minimal */
1489                         else if (dir > 0)
1490                                 t -= ((time_t) 1) << bits;
1491                         else    t += ((time_t) 1) << bits;
1492                         continue;
1493                 }
1494                 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1495                         break;
1496                 /*
1497                 ** Right time, wrong type.
1498                 ** Hunt for right time, right type.
1499                 ** It's okay to guess wrong since the guess
1500                 ** gets checked.
1501                 */
1502                 /*
1503                 ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1504                 */
1505                 sp = (const struct state *)
1506                         (((void *) funcp == (void *) localsub) ?
1507                         lclptr : gmtptr);
1508 #ifdef ALL_STATE
1509                 if (sp == NULL)
1510                         return WRONG;
1511 #endif /* defined ALL_STATE */
1512                 for (i = sp->typecnt - 1; i >= 0; --i) {
1513                         if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1514                                 continue;
1515                         for (j = sp->typecnt - 1; j >= 0; --j) {
1516                                 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1517                                         continue;
1518                                 newt = t + sp->ttis[j].tt_gmtoff -
1519                                         sp->ttis[i].tt_gmtoff;
1520                                 (*funcp)(&newt, offset, &mytm);
1521                                 if (tmcomp(&mytm, &yourtm) != 0)
1522                                         continue;
1523                                 if (mytm.tm_isdst != yourtm.tm_isdst)
1524                                         continue;
1525                                 /*
1526                                 ** We have a match.
1527                                 */
1528                                 t = newt;
1529                                 goto label;
1530                         }
1531                 }
1532                 return WRONG;
1533         }
1534 label:
1535         newt = t + saved_seconds;
1536         if ((newt < t) != (saved_seconds < 0))
1537                 return WRONG;
1538         t = newt;
1539         (*funcp)(&t, offset, tmp);
1540         *okayp = TRUE;
1541         return t;
1542 }
1543
1544 static time_t
1545 time1(tmp, funcp, offset)
1546 struct tm * const       tmp;
1547 void (* const           funcp) P((const time_t *, long, struct tm *));
1548 const long              offset;
1549 {
1550         time_t                  t;
1551         const struct state *    sp;
1552         int                     samei, otheri;
1553         int                             okay;
1554
1555         if (tmp->tm_isdst > 1)
1556                 tmp->tm_isdst = 1;
1557         t = time2(tmp, funcp, offset, &okay);
1558 #ifdef PCTS
1559         /*
1560         ** PCTS code courtesy Grant Sullivan (grant@osf.org).
1561         */
1562         if (okay)
1563                 return t;
1564         if (tmp->tm_isdst < 0)
1565                 tmp->tm_isdst = 0;      /* reset to std and try again */
1566 #endif /* defined PCTS */
1567 #ifndef PCTS
1568         if (okay || tmp->tm_isdst < 0)
1569                 return t;
1570 #endif /* !defined PCTS */
1571         /*
1572         ** We're supposed to assume that somebody took a time of one type
1573         ** and did some math on it that yielded a "struct tm" that's bad.
1574         ** We try to divine the type they started from and adjust to the
1575         ** type they need.
1576         */
1577         /*
1578         ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1579         */
1580         sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
1581                 lclptr : gmtptr);
1582 #ifdef ALL_STATE
1583         if (sp == NULL)
1584                 return WRONG;
1585 #endif /* defined ALL_STATE */
1586         for (samei = sp->typecnt - 1; samei >= 0; --samei) {
1587                 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1588                         continue;
1589                 for (otheri = sp->typecnt - 1; otheri >= 0; --otheri) {
1590                         if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1591                                 continue;
1592                         tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1593                                         sp->ttis[samei].tt_gmtoff;
1594                         tmp->tm_isdst = !tmp->tm_isdst;
1595                         t = time2(tmp, funcp, offset, &okay);
1596                         if (okay)
1597                                 return t;
1598                         tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1599                                         sp->ttis[samei].tt_gmtoff;
1600                         tmp->tm_isdst = !tmp->tm_isdst;
1601                 }
1602         }
1603         return WRONG;
1604 }
1605
1606 time_t
1607 mktime(tmp)
1608 struct tm * const       tmp;
1609 {
1610         time_t mktime_return_value;
1611         _MUTEX_LOCK(&lcl_mutex);
1612         tzset();
1613         mktime_return_value = time1(tmp, localsub, 0L);
1614         _MUTEX_UNLOCK(&lcl_mutex);
1615         return(mktime_return_value);
1616 }
1617
1618 #ifdef STD_INSPIRED
1619
1620 time_t
1621 timelocal(tmp)
1622 struct tm * const       tmp;
1623 {
1624         tmp->tm_isdst = -1;     /* in case it wasn't initialized */
1625         return mktime(tmp);
1626 }
1627
1628 time_t
1629 timegm(tmp)
1630 struct tm * const       tmp;
1631 {
1632         tmp->tm_isdst = 0;
1633         return time1(tmp, gmtsub, 0L);
1634 }
1635
1636 time_t
1637 timeoff(tmp, offset)
1638 struct tm * const       tmp;
1639 const long              offset;
1640 {
1641         tmp->tm_isdst = 0;
1642         return time1(tmp, gmtsub, offset);
1643 }
1644
1645 #endif /* defined STD_INSPIRED */
1646
1647 #ifdef CMUCS
1648
1649 /*
1650 ** The following is supplied for compatibility with
1651 ** previous versions of the CMUCS runtime library.
1652 */
1653
1654 long
1655 gtime(tmp)
1656 struct tm * const       tmp;
1657 {
1658         const time_t    t = mktime(tmp);
1659
1660         if (t == WRONG)
1661                 return -1;
1662         return t;
1663 }
1664
1665 #endif /* defined CMUCS */
1666
1667 /*
1668 ** XXX--is the below the right way to conditionalize??
1669 */
1670
1671 #ifdef STD_INSPIRED
1672
1673 /*
1674 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1675 ** shall correspond to "Wed Dec 31 23:59:59 GMT 1986", which
1676 ** is not the case if we are accounting for leap seconds.
1677 ** So, we provide the following conversion routines for use
1678 ** when exchanging timestamps with POSIX conforming systems.
1679 */
1680
1681 static long
1682 leapcorr(timep)
1683 time_t *        timep;
1684 {
1685         struct state *          sp;
1686         struct lsinfo * lp;
1687         int                     i;
1688
1689         sp = lclptr;
1690         i = sp->leapcnt;
1691         while (--i >= 0) {
1692                 lp = &sp->lsis[i];
1693                 if (*timep >= lp->ls_trans)
1694                         return lp->ls_corr;
1695         }
1696         return 0;
1697 }
1698
1699 time_t
1700 time2posix(t)
1701 time_t  t;
1702 {
1703         tzset();
1704         return t - leapcorr(&t);
1705 }
1706
1707 time_t
1708 posix2time(t)
1709 time_t  t;
1710 {
1711         time_t  x;
1712         time_t  y;
1713
1714         tzset();
1715         /*
1716         ** For a positive leap second hit, the result
1717         ** is not unique.  For a negative leap second
1718         ** hit, the corresponding time doesn't exist,
1719         ** so we return an adjacent second.
1720         */
1721         x = t + leapcorr(&t);
1722         y = x - leapcorr(&x);
1723         if (y < t) {
1724                 do {
1725                         x++;
1726                         y = x - leapcorr(&x);
1727                 } while (y < t);
1728                 if (t != y)
1729                         return x - 1;
1730         } else if (y > t) {
1731                 do {
1732                         --x;
1733                         y = x - leapcorr(&x);
1734                 } while (y > t);
1735                 if (t != y)
1736                         return x + 1;
1737         }
1738         return x;
1739 }
1740
1741 #endif /* defined STD_INSPIRED */