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
   6 #ifndef lint
   7 #ifndef NOID
   8 static char     elsieid[] = "@(#)localtime.c    7.57";
   9 #endif /* !defined NOID */
  10 #endif /* !defined lint */
  11 #include <sys/cdefs.h>
  12 __FBSDID("$FreeBSD$");
  13
  14 /*
  15 ** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
  16 ** POSIX-style TZ environment variable handling from Guy Harris
  17 ** (guy@auspex.com).
  18 */
  19
  20 /*LINTLIBRARY*/
  21
  22 #include "namespace.h"
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <pthread.h>
  27 #include "private.h"
  28 #include "un-namespace.h"
  29
  30 #include "tzfile.h"
  31
  32 #include "libc_private.h"
  33
  34 #define _MUTEX_LOCK(x)          if (__isthreaded) _pthread_mutex_lock(x)
  35 #define _MUTEX_UNLOCK(x)        if (__isthreaded) _pthread_mutex_unlock(x)
  36
  37 /*
  38 ** SunOS 4.1.1 headers lack O_BINARY.
  39 */
  40
  41 #ifdef O_BINARY
  42 #define OPEN_MODE       (O_RDONLY | O_BINARY)
  43 #endif /* defined O_BINARY */
  44 #ifndef O_BINARY
  45 #define OPEN_MODE       O_RDONLY
  46 #endif /* !defined O_BINARY */
  47
  48 #ifndef WILDABBR
  49 /*
  50 ** Someone might make incorrect use of a time zone abbreviation:
  51 **      1.      They might reference tzname[0] before calling tzset (explicitly
  52 **              or implicitly).
  53 **      2.      They might reference tzname[1] before calling tzset (explicitly
  54 **              or implicitly).
  55 **      3.      They might reference tzname[1] after setting to a time zone
  56 **              in which Daylight Saving Time is never observed.
  57 **      4.      They might reference tzname[0] after setting to a time zone
  58 **              in which Standard Time is never observed.
  59 **      5.      They might reference tm.TM_ZONE after calling offtime.
  60 ** What's best to do in the above cases is open to debate;
  61 ** for now, we just set things up so that in any of the five cases
  62 ** WILDABBR is used.  Another possibility:  initialize tzname[0] to the
  63 ** string "tzname[0] used before set", and similarly for the other cases.
  64 ** And another:  initialize tzname[0] to "ERA", with an explanation in the
  65 ** manual page of what this "time zone abbreviation" means (doing this so
  66 ** that tzname[0] has the "normal" length of three characters).
  67 */
  68 #define WILDABBR        "   "
  69 #endif /* !defined WILDABBR */
  70
  71 static char             wildabbr[] = "WILDABBR";
  72
  73 static const char       gmt[] = "GMT";
  74
  75 struct ttinfo {                         /* time type information */
  76         long            tt_gmtoff;      /* GMT offset in seconds */
  77         int             tt_isdst;       /* used to set tm_isdst */
  78         int             tt_abbrind;     /* abbreviation list index */
  79         int             tt_ttisstd;     /* TRUE if transition is std time */
  80         int             tt_ttisgmt;     /* TRUE if transition is GMT */
  81 };
  82
  83 struct lsinfo {                         /* leap second information */
  84         time_t          ls_trans;       /* transition time */
  85         long            ls_corr;        /* correction to apply */
  86 };
  87
  88 #define BIGGEST(a, b)   (((a) > (b)) ? (a) : (b))
  89
  90 #ifdef TZNAME_MAX
  91 #define MY_TZNAME_MAX   TZNAME_MAX
  92 #endif /* defined TZNAME_MAX */
  93 #ifndef TZNAME_MAX
  94 #define MY_TZNAME_MAX   255
  95 #endif /* !defined TZNAME_MAX */
  96
  97 struct state {
  98         int             leapcnt;
  99         int             timecnt;
 100         int             typecnt;
 101         int             charcnt;
 102         time_t          ats[TZ_MAX_TIMES];
 103         unsigned char   types[TZ_MAX_TIMES];
 104         struct ttinfo   ttis[TZ_MAX_TYPES];
 105         char            chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
 106                                 (2 * (MY_TZNAME_MAX + 1)))];
 107         struct lsinfo   lsis[TZ_MAX_LEAPS];
 108 };
 109
 110 struct rule {
 111         int             r_type;         /* type of rule--see below */
 112         int             r_day;          /* day number of rule */
 113         int             r_week;         /* week number of rule */
 114         int             r_mon;          /* month number of rule */
 115         long            r_time;         /* transition time of rule */
 116 };
 117
 118 #define JULIAN_DAY              0       /* Jn - Julian day */
 119 #define DAY_OF_YEAR             1       /* n - day of year */
 120 #define MONTH_NTH_DAY_OF_WEEK   2       /* Mm.n.d - month, week, day of week */
 121
 122 /*
 123 ** Prototypes for static functions.
 124 */
 125
 126 static long             detzcode(const char * codep);
 127 static const char *     getzname(const char * strp);
 128 static const char *     getnum(const char * strp, int * nump, int min,
 129                                 int max);
 130 static const char *     getsecs(const char * strp, long * secsp);
 131 static const char *     getoffset(const char * strp, long * offsetp);
 132 static const char *     getrule(const char * strp, struct rule * rulep);
 133 static void             gmtload(struct state * sp);
 134 static void             gmtsub(const time_t * timep, long offset,
 135                                 struct tm * tmp);
 136 static void             localsub(const time_t * timep, long offset,
 137                                 struct tm * tmp);
 138 static int              increment_overflow(int * number, int delta);
 139 static int              normalize_overflow(int * tensptr, int * unitsptr,
 140                                 int base);
 141 static void             settzname(void);
 142 static time_t           time1(struct tm * tmp,
 143                                 void(*funcp) (const time_t *,
 144                                 long, struct tm *),
 145                                 long offset);
 146 static time_t           time2(struct tm *tmp,
 147                                 void(*funcp) (const time_t *,
 148                                 long, struct tm*),
 149                                 long offset, int * okayp);
 150 static void             timesub(const time_t * timep, long offset,
 151                                 const struct state * sp, struct tm * tmp);
 152 static int              tmcomp(const struct tm * atmp,
 153                                 const struct tm * btmp);
 154 static time_t           transtime(time_t janfirst, int year,
 155                                 const struct rule * rulep, long offset);
 156 static int              tzload(const char * name, struct state * sp);
 157 static int              tzparse(const char * name, struct state * sp,
 158                                 int lastditch);
 159
 160 #ifdef ALL_STATE
 161 static struct state *   lclptr;
 162 static struct state *   gmtptr;
 163 #endif /* defined ALL_STATE */
 164
 165 #ifndef ALL_STATE
 166 static struct state     lclmem;
 167 static struct state     gmtmem;
 168 #define lclptr          (&lclmem)
 169 #define gmtptr          (&gmtmem)
 170 #endif /* State Farm */
 171
 172 #ifndef TZ_STRLEN_MAX
 173 #define TZ_STRLEN_MAX 255
 174 #endif /* !defined TZ_STRLEN_MAX */
 175
 176 static char             lcl_TZname[TZ_STRLEN_MAX + 1];
 177 static int              lcl_is_set;
 178 static int              gmt_is_set;
 179 static pthread_mutex_t  lcl_mutex = PTHREAD_MUTEX_INITIALIZER;
 180 static pthread_mutex_t  gmt_mutex = PTHREAD_MUTEX_INITIALIZER;
 181
 182 char *                  tzname[2] = {
 183         wildabbr,
 184         wildabbr
 185 };
 186
 187 /*
 188 ** Section 4.12.3 of X3.159-1989 requires that
 189 **      Except for the strftime function, these functions [asctime,
 190 **      ctime, gmtime, localtime] return values in one of two static
 191 **      objects: a broken-down time structure and an array of char.
 192 ** Thanks to Paul Eggert (eggert@twinsun.com) for noting this.
 193 */
 194
 195 static struct tm        tm;
 196
 197 #ifdef USG_COMPAT
 198 time_t                  timezone = 0;
 199 int                     daylight = 0;
 200 #endif /* defined USG_COMPAT */
 201
 202 #ifdef ALTZONE
 203 time_t                  altzone = 0;
 204 #endif /* defined ALTZONE */
 205
 206 static long
 207 detzcode(codep)
 208 const char * const      codep;
 209 {
 210         long    result;
 211         int     i;
 212
 213         result = (codep[0] & 0x80) ? ~0L : 0L;
 214         for (i = 0; i < 4; ++i)
 215                 result = (result << 8) | (codep[i] & 0xff);
 216         return result;
 217 }
 218
 219 static void
 220 settzname(void)
 221 {
 222         struct state *  sp = lclptr;
 223         int                     i;
 224
 225         tzname[0] = wildabbr;
 226         tzname[1] = wildabbr;
 227 #ifdef USG_COMPAT
 228         daylight = 0;
 229         timezone = 0;
 230 #endif /* defined USG_COMPAT */
 231 #ifdef ALTZONE
 232         altzone = 0;
 233 #endif /* defined ALTZONE */
 234 #ifdef ALL_STATE
 235         if (sp == NULL) {
 236                 tzname[0] = tzname[1] = gmt;
 237                 return;
 238         }
 239 #endif /* defined ALL_STATE */
 240         for (i = 0; i < sp->typecnt; ++i) {
 241                 const struct ttinfo * const     ttisp = &sp->ttis[i];
 242
 243                 tzname[ttisp->tt_isdst] =
 244                         &sp->chars[ttisp->tt_abbrind];
 245 #ifdef USG_COMPAT
 246                 if (ttisp->tt_isdst)
 247                         daylight = 1;
 248                 if (i == 0 || !ttisp->tt_isdst)
 249                         timezone = -(ttisp->tt_gmtoff);
 250 #endif /* defined USG_COMPAT */
 251 #ifdef ALTZONE
 252                 if (i == 0 || ttisp->tt_isdst)
 253                         altzone = -(ttisp->tt_gmtoff);
 254 #endif /* defined ALTZONE */
 255         }
 256         /*
 257         ** And to get the latest zone names into tzname. . .
 258         */
 259         for (i = 0; i < sp->timecnt; ++i) {
 260                 const struct ttinfo * const     ttisp =
 261                                                         &sp->ttis[
 262                                                                 sp->types[i]];
 263
 264                 tzname[ttisp->tt_isdst] =
 265                         &sp->chars[ttisp->tt_abbrind];
 266         }
 267 }
 268
 269 static int
 270 tzload(name, sp)
 271 const char *            name;
 272 struct state * const    sp;
 273 {
 274         const char *    p;
 275         int             i;
 276         int             fid;
 277
 278         /* XXX The following is from OpenBSD, and I'm not sure it is correct */
 279         if (name != NULL && issetugid() != 0)
 280                 if ((name[0] == ':' && name[1] == '/') ||
 281                     name[0] == '/' || strchr(name, '.'))
 282                         name = NULL;
 283         if (name == NULL && (name = TZDEFAULT) == NULL)
 284                 return -1;
 285         {
 286                 int     doaccess;
 287                 struct stat     stab;
 288                 /*
 289                 ** Section 4.9.1 of the C standard says that
 290                 ** "FILENAME_MAX expands to an integral constant expression
 291                 ** that is the size needed for an array of char large enough
 292                 ** to hold the longest file name string that the implementation
 293                 ** guarantees can be opened."
 294                 */
 295                 char            fullname[FILENAME_MAX + 1];
 296
 297                 if (name[0] == ':')
 298                         ++name;
 299                 doaccess = name[0] == '/';
 300                 if (!doaccess) {
 301                         if ((p = TZDIR) == NULL)
 302                                 return -1;
 303                         if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
 304                                 return -1;
 305                         (void) strcpy(fullname, p);
 306                         (void) strcat(fullname, "/");
 307                         (void) strcat(fullname, name);
 308                         /*
 309                         ** Set doaccess if '.' (as in "../") shows up in name.
 310                         */
 311                         if (strchr(name, '.') != NULL)
 312                                 doaccess = TRUE;
 313                         name = fullname;
 314                 }
 315                 if (doaccess && access(name, R_OK) != 0)
 316                         return -1;
 317                 if ((fid = _open(name, OPEN_MODE)) == -1)
 318                         return -1;
 319                 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
 320                         _close(fid);
 321                         return -1;
 322                 }
 323         }
 324         {
 325                 struct tzhead * tzhp;
 326                 char            buf[sizeof *sp + sizeof *tzhp];
 327                 int             ttisstdcnt;
 328                 int             ttisgmtcnt;
 329
 330                 i = _read(fid, buf, sizeof buf);
 331                 if (_close(fid) != 0)
 332                         return -1;
 333                 p = buf;
 334                 p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
 335                 ttisstdcnt = (int) detzcode(p);
 336                 p += 4;
 337                 ttisgmtcnt = (int) detzcode(p);
 338                 p += 4;
 339                 sp->leapcnt = (int) detzcode(p);
 340                 p += 4;
 341                 sp->timecnt = (int) detzcode(p);
 342                 p += 4;
 343                 sp->typecnt = (int) detzcode(p);
 344                 p += 4;
 345                 sp->charcnt = (int) detzcode(p);
 346                 p += 4;
 347                 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
 348                         sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
 349                         sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
 350                         sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
 351                         (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
 352                         (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
 353                                 return -1;
 354                 if (i - (p - buf) < sp->timecnt * 4 +   /* ats */
 355                         sp->timecnt +                   /* types */
 356                         sp->typecnt * (4 + 2) +         /* ttinfos */
 357                         sp->charcnt +                   /* chars */
 358                         sp->leapcnt * (4 + 4) +         /* lsinfos */
 359                         ttisstdcnt +                    /* ttisstds */
 360                         ttisgmtcnt)                     /* ttisgmts */
 361                                 return -1;
 362                 for (i = 0; i < sp->timecnt; ++i) {
 363                         sp->ats[i] = detzcode(p);
 364                         p += 4;
 365                 }
 366                 for (i = 0; i < sp->timecnt; ++i) {
 367                         sp->types[i] = (unsigned char) *p++;
 368                         if (sp->types[i] >= sp->typecnt)
 369                                 return -1;
 370                 }
 371                 for (i = 0; i < sp->typecnt; ++i) {
 372                         struct ttinfo * ttisp;
 373
 374                         ttisp = &sp->ttis[i];
 375                         ttisp->tt_gmtoff = detzcode(p);
 376                         p += 4;
 377                         ttisp->tt_isdst = (unsigned char) *p++;
 378                         if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
 379                                 return -1;
 380                         ttisp->tt_abbrind = (unsigned char) *p++;
 381                         if (ttisp->tt_abbrind < 0 ||
 382                                 ttisp->tt_abbrind > sp->charcnt)
 383                                         return -1;
 384                 }
 385                 for (i = 0; i < sp->charcnt; ++i)
 386                         sp->chars[i] = *p++;
 387                 sp->chars[i] = '\0';    /* ensure '\0' at end */
 388                 for (i = 0; i < sp->leapcnt; ++i) {
 389                         struct lsinfo * lsisp;
 390
 391                         lsisp = &sp->lsis[i];
 392                         lsisp->ls_trans = detzcode(p);
 393                         p += 4;
 394                         lsisp->ls_corr = detzcode(p);
 395                         p += 4;
 396                 }
 397                 for (i = 0; i < sp->typecnt; ++i) {
 398                         struct ttinfo * ttisp;
 399
 400                         ttisp = &sp->ttis[i];
 401                         if (ttisstdcnt == 0)
 402                                 ttisp->tt_ttisstd = FALSE;
 403                         else {
 404                                 ttisp->tt_ttisstd = *p++;
 405                                 if (ttisp->tt_ttisstd != TRUE &&
 406                                         ttisp->tt_ttisstd != FALSE)
 407                                                 return -1;
 408                         }
 409                 }
 410                 for (i = 0; i < sp->typecnt; ++i) {
 411                         struct ttinfo * ttisp;
 412
 413                         ttisp = &sp->ttis[i];
 414                         if (ttisgmtcnt == 0)
 415                                 ttisp->tt_ttisgmt = FALSE;
 416                         else {
 417                                 ttisp->tt_ttisgmt = *p++;
 418                                 if (ttisp->tt_ttisgmt != TRUE &&
 419                                         ttisp->tt_ttisgmt != FALSE)
 420                                                 return -1;
 421                         }
 422                 }
 423         }
 424         return 0;
 425 }
 426
 427 static const int        mon_lengths[2][MONSPERYEAR] = {
 428         { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 429         { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 430 };
 431
 432 static const int        year_lengths[2] = {
 433         DAYSPERNYEAR, DAYSPERLYEAR
 434 };
 435
 436 /*
 437 ** Given a pointer into a time zone string, scan until a character that is not
 438 ** a valid character in a zone name is found.  Return a pointer to that
 439 ** character.
 440 */
 441
 442 static const char *
 443 getzname(strp)
 444 const char *    strp;
 445 {
 446         char    c;
 447
 448         while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
 449                 c != '+')
 450                         ++strp;
 451         return strp;
 452 }
 453
 454 /*
 455 ** Given a pointer into a time zone string, extract a number from that string.
 456 ** Check that the number is within a specified range; if it is not, return
 457 ** NULL.
 458 ** Otherwise, return a pointer to the first character not part of the number.
 459 */
 460
 461 static const char *
 462 getnum(strp, nump, min, max)
 463 const char *    strp;
 464 int * const             nump;
 465 const int               min;
 466 const int               max;
 467 {
 468         char    c;
 469         int     num;
 470
 471         if (strp == NULL || !is_digit(c = *strp))
 472                 return NULL;
 473         num = 0;
 474         do {
 475                 num = num * 10 + (c - '0');
 476                 if (num > max)
 477                         return NULL;    /* illegal value */
 478                 c = *++strp;
 479         } while (is_digit(c));
 480         if (num < min)
 481                 return NULL;            /* illegal value */
 482         *nump = num;
 483         return strp;
 484 }
 485
 486 /*
 487 ** Given a pointer into a time zone string, extract a number of seconds,
 488 ** in hh[:mm[:ss]] form, from the string.
 489 ** If any error occurs, return NULL.
 490 ** Otherwise, return a pointer to the first character not part of the number
 491 ** of seconds.
 492 */
 493
 494 static const char *
 495 getsecs(strp, secsp)
 496 const char *    strp;
 497 long * const            secsp;
 498 {
 499         int     num;
 500
 501         /*
 502         ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
 503         ** "M10.4.6/26", which does not conform to Posix,
 504         ** but which specifies the equivalent of
 505         ** ``02:00 on the first Sunday on or after 23 Oct''.
 506         */
 507         strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
 508         if (strp == NULL)
 509                 return NULL;
 510         *secsp = num * (long) SECSPERHOUR;
 511         if (*strp == ':') {
 512                 ++strp;
 513                 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
 514                 if (strp == NULL)
 515                         return NULL;
 516                 *secsp += num * SECSPERMIN;
 517                 if (*strp == ':') {
 518                         ++strp;
 519                         /* `SECSPERMIN' allows for leap seconds.  */
 520                         strp = getnum(strp, &num, 0, SECSPERMIN);
 521                         if (strp == NULL)
 522                                 return NULL;
 523                         *secsp += num;
 524                 }
 525         }
 526         return strp;
 527 }
 528
 529 /*
 530 ** Given a pointer into a time zone string, extract an offset, in
 531 ** [+-]hh[:mm[:ss]] form, from the string.
 532 ** If any error occurs, return NULL.
 533 ** Otherwise, return a pointer to the first character not part of the time.
 534 */
 535
 536 static const char *
 537 getoffset(strp, offsetp)
 538 const char *    strp;
 539 long * const            offsetp;
 540 {
 541         int     neg = 0;
 542
 543         if (*strp == '-') {
 544                 neg = 1;
 545                 ++strp;
 546         } else if (*strp == '+')
 547                 ++strp;
 548         strp = getsecs(strp, offsetp);
 549         if (strp == NULL)
 550                 return NULL;            /* illegal time */
 551         if (neg)
 552                 *offsetp = -*offsetp;
 553         return strp;
 554 }
 555
 556 /*
 557 ** Given a pointer into a time zone string, extract a rule in the form
 558 ** date[/time].  See POSIX section 8 for the format of "date" and "time".
 559 ** If a valid rule is not found, return NULL.
 560 ** Otherwise, return a pointer to the first character not part of the rule.
 561 */
 562
 563 static const char *
 564 getrule(strp, rulep)
 565 const char *                    strp;
 566 struct rule * const     rulep;
 567 {
 568         if (*strp == 'J') {
 569                 /*
 570                 ** Julian day.
 571                 */
 572                 rulep->r_type = JULIAN_DAY;
 573                 ++strp;
 574                 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
 575         } else if (*strp == 'M') {
 576                 /*
 577                 ** Month, week, day.
 578                 */
 579                 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
 580                 ++strp;
 581                 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
 582                 if (strp == NULL)
 583                         return NULL;
 584                 if (*strp++ != '.')
 585                         return NULL;
 586                 strp = getnum(strp, &rulep->r_week, 1, 5);
 587                 if (strp == NULL)
 588                         return NULL;
 589                 if (*strp++ != '.')
 590                         return NULL;
 591                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
 592         } else if (is_digit(*strp)) {
 593                 /*
 594                 ** Day of year.
 595                 */
 596                 rulep->r_type = DAY_OF_YEAR;
 597                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
 598         } else  return NULL;            /* invalid format */
 599         if (strp == NULL)
 600                 return NULL;
 601         if (*strp == '/') {
 602                 /*
 603                 ** Time specified.
 604                 */
 605                 ++strp;
 606                 strp = getsecs(strp, &rulep->r_time);
 607         } else  rulep->r_time = 2 * SECSPERHOUR;        /* default = 2:00:00 */
 608         return strp;
 609 }
 610
 611 /*
 612 ** Given the Epoch-relative time of January 1, 00:00:00 GMT, in a year, the
 613 ** year, a rule, and the offset from GMT at the time that rule takes effect,
 614 ** calculate the Epoch-relative time that rule takes effect.
 615 */
 616
 617 static time_t
 618 transtime(janfirst, year, rulep, offset)
 619 const time_t                            janfirst;
 620 const int                               year;
 621 const struct rule * const       rulep;
 622 const long                              offset;
 623 {
 624         int     leapyear;
 625         time_t  value;
 626         int     i;
 627         int             d, m1, yy0, yy1, yy2, dow;
 628
 629         INITIALIZE(value);
 630         leapyear = isleap(year);
 631         switch (rulep->r_type) {
 632
 633         case JULIAN_DAY:
 634                 /*
 635                 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
 636                 ** years.
 637                 ** In non-leap years, or if the day number is 59 or less, just
 638                 ** add SECSPERDAY times the day number-1 to the time of
 639                 ** January 1, midnight, to get the day.
 640                 */
 641                 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
 642                 if (leapyear && rulep->r_day >= 60)
 643                         value += SECSPERDAY;
 644                 break;
 645
 646         case DAY_OF_YEAR:
 647                 /*
 648                 ** n - day of year.
 649                 ** Just add SECSPERDAY times the day number to the time of
 650                 ** January 1, midnight, to get the day.
 651                 */
 652                 value = janfirst + rulep->r_day * SECSPERDAY;
 653                 break;
 654
 655         case MONTH_NTH_DAY_OF_WEEK:
 656                 /*
 657                 ** Mm.n.d - nth "dth day" of month m.
 658                 */
 659                 value = janfirst;
 660                 for (i = 0; i < rulep->r_mon - 1; ++i)
 661                         value += mon_lengths[leapyear][i] * SECSPERDAY;
 662
 663                 /*
 664                 ** Use Zeller's Congruence to get day-of-week of first day of
 665                 ** month.
 666                 */
 667                 m1 = (rulep->r_mon + 9) % 12 + 1;
 668                 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
 669                 yy1 = yy0 / 100;
 670                 yy2 = yy0 % 100;
 671                 dow = ((26 * m1 - 2) / 10 +
 672                         1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
 673                 if (dow < 0)
 674                         dow += DAYSPERWEEK;
 675
 676                 /*
 677                 ** "dow" is the day-of-week of the first day of the month.  Get
 678                 ** the day-of-month (zero-origin) of the first "dow" day of the
 679                 ** month.
 680                 */
 681                 d = rulep->r_day - dow;
 682                 if (d < 0)
 683                         d += DAYSPERWEEK;
 684                 for (i = 1; i < rulep->r_week; ++i) {
 685                         if (d + DAYSPERWEEK >=
 686                                 mon_lengths[leapyear][rulep->r_mon - 1])
 687                                         break;
 688                         d += DAYSPERWEEK;
 689                 }
 690
 691                 /*
 692                 ** "d" is the day-of-month (zero-origin) of the day we want.
 693                 */
 694                 value += d * SECSPERDAY;
 695                 break;
 696         }
 697
 698         /*
 699         ** "value" is the Epoch-relative time of 00:00:00 GMT on the day in
 700         ** question.  To get the Epoch-relative time of the specified local
 701         ** time on that day, add the transition time and the current offset
 702         ** from GMT.
 703         */
 704         return value + rulep->r_time + offset;
 705 }
 706
 707 /*
 708 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
 709 ** appropriate.
 710 */
 711
 712 static int
 713 tzparse(name, sp, lastditch)
 714 const char *                    name;
 715 struct state * const    sp;
 716 const int                       lastditch;
 717 {
 718         const char *                    stdname;
 719         const char *                    dstname;
 720         size_t                          stdlen;
 721         size_t                          dstlen;
 722         long                            stdoffset;
 723         long                            dstoffset;
 724         time_t *                atp;
 725         unsigned char * typep;
 726         char *                  cp;
 727         int                     load_result;
 728
 729         INITIALIZE(dstname);
 730         stdname = name;
 731         if (lastditch) {
 732                 stdlen = strlen(name);  /* length of standard zone name */
 733                 name += stdlen;
 734                 if (stdlen >= sizeof sp->chars)
 735                         stdlen = (sizeof sp->chars) - 1;
 736                 stdoffset = 0;
 737         } else {
 738                 name = getzname(name);
 739                 stdlen = name - stdname;
 740                 if (stdlen < 3)
 741                         return -1;
 742                 if (*name == '\0')
 743                         return -1;      /* was "stdoffset = 0;" */
 744                 else {
 745                         name = getoffset(name, &stdoffset);
 746                         if (name == NULL)
 747                                 return -1;
 748                 }
 749         }
 750         load_result = tzload(TZDEFRULES, sp);
 751         if (load_result != 0)
 752                 sp->leapcnt = 0;                /* so, we're off a little */
 753         if (*name != '\0') {
 754                 dstname = name;
 755                 name = getzname(name);
 756                 dstlen = name - dstname;        /* length of DST zone name */
 757                 if (dstlen < 3)
 758                         return -1;
 759                 if (*name != '\0' && *name != ',' && *name != ';') {
 760                         name = getoffset(name, &dstoffset);
 761                         if (name == NULL)
 762                                 return -1;
 763                 } else  dstoffset = stdoffset - SECSPERHOUR;
 764                 if (*name == ',' || *name == ';') {
 765                         struct rule     start;
 766                         struct rule     end;
 767                         int     year;
 768                         time_t  janfirst;
 769                         time_t          starttime;
 770                         time_t          endtime;
 771
 772                         ++name;
 773                         if ((name = getrule(name, &start)) == NULL)
 774                                 return -1;
 775                         if (*name++ != ',')
 776                                 return -1;
 777                         if ((name = getrule(name, &end)) == NULL)
 778                                 return -1;
 779                         if (*name != '\0')
 780                                 return -1;
 781                         sp->typecnt = 2;        /* standard time and DST */
 782                         /*
 783                         ** Two transitions per year, from EPOCH_YEAR to 2037.
 784                         */
 785                         sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
 786                         if (sp->timecnt > TZ_MAX_TIMES)
 787                                 return -1;
 788                         sp->ttis[0].tt_gmtoff = -dstoffset;
 789                         sp->ttis[0].tt_isdst = 1;
 790                         sp->ttis[0].tt_abbrind = stdlen + 1;
 791                         sp->ttis[1].tt_gmtoff = -stdoffset;
 792                         sp->ttis[1].tt_isdst = 0;
 793                         sp->ttis[1].tt_abbrind = 0;
 794                         atp = sp->ats;
 795                         typep = sp->types;
 796                         janfirst = 0;
 797                         for (year = EPOCH_YEAR; year <= 2037; ++year) {
 798                                 starttime = transtime(janfirst, year, &start,
 799                                         stdoffset);
 800                                 endtime = transtime(janfirst, year, &end,
 801                                         dstoffset);
 802                                 if (starttime > endtime) {
 803                                         *atp++ = endtime;
 804                                         *typep++ = 1;   /* DST ends */
 805                                         *atp++ = starttime;
 806                                         *typep++ = 0;   /* DST begins */
 807                                 } else {
 808                                         *atp++ = starttime;
 809                                         *typep++ = 0;   /* DST begins */
 810                                         *atp++ = endtime;
 811                                         *typep++ = 1;   /* DST ends */
 812                                 }
 813                                 janfirst += year_lengths[isleap(year)] *
 814                                         SECSPERDAY;
 815                         }
 816                 } else {
 817                         long    theirstdoffset;
 818                         long    theirdstoffset;
 819                         long    theiroffset;
 820                         int     isdst;
 821                         int     i;
 822                         int     j;
 823
 824                         if (*name != '\0')
 825                                 return -1;
 826                         if (load_result != 0)
 827                                 return -1;
 828                         /*
 829                         ** Initial values of theirstdoffset and theirdstoffset.
 830                         */
 831                         theirstdoffset = 0;
 832                         for (i = 0; i < sp->timecnt; ++i) {
 833                                 j = sp->types[i];
 834                                 if (!sp->ttis[j].tt_isdst) {
 835                                         theirstdoffset =
 836                                                 -sp->ttis[j].tt_gmtoff;
 837                                         break;
 838                                 }
 839                         }
 840                         theirdstoffset = 0;
 841                         for (i = 0; i < sp->timecnt; ++i) {
 842                                 j = sp->types[i];
 843                                 if (sp->ttis[j].tt_isdst) {
 844                                         theirdstoffset =
 845                                                 -sp->ttis[j].tt_gmtoff;
 846                                         break;
 847                                 }
 848                         }
 849                         /*
 850                         ** Initially we're assumed to be in standard time.
 851                         */
 852                         isdst = FALSE;
 853                         theiroffset = theirstdoffset;
 854                         /*
 855                         ** Now juggle transition times and types
 856                         ** tracking offsets as you do.
 857                         */
 858                         for (i = 0; i < sp->timecnt; ++i) {
 859                                 j = sp->types[i];
 860                                 sp->types[i] = sp->ttis[j].tt_isdst;
 861                                 if (sp->ttis[j].tt_ttisgmt) {
 862                                         /* No adjustment to transition time */
 863                                 } else {
 864                                         /*
 865                                         ** If summer time is in effect, and the
 866                                         ** transition time was not specified as
 867                                         ** standard time, add the summer time
 868                                         ** offset to the transition time;
 869                                         ** otherwise, add the standard time
 870                                         ** offset to the transition time.
 871                                         */
 872                                         /*
 873                                         ** Transitions from DST to DDST
 874                                         ** will effectively disappear since
 875                                         ** POSIX provides for only one DST
 876                                         ** offset.
 877                                         */
 878                                         if (isdst && !sp->ttis[j].tt_ttisstd) {
 879                                                 sp->ats[i] += dstoffset -
 880                                                         theirdstoffset;
 881                                         } else {
 882                                                 sp->ats[i] += stdoffset -
 883                                                         theirstdoffset;
 884                                         }
 885                                 }
 886                                 theiroffset = -sp->ttis[j].tt_gmtoff;
 887                                 if (sp->ttis[j].tt_isdst)
 888                                         theirdstoffset = theiroffset;
 889                                 else    theirstdoffset = theiroffset;
 890                         }
 891                         /*
 892                         ** Finally, fill in ttis.
 893                         ** ttisstd and ttisgmt need not be handled.
 894                         */
 895                         sp->ttis[0].tt_gmtoff = -stdoffset;
 896                         sp->ttis[0].tt_isdst = FALSE;
 897                         sp->ttis[0].tt_abbrind = 0;
 898                         sp->ttis[1].tt_gmtoff = -dstoffset;
 899                         sp->ttis[1].tt_isdst = TRUE;
 900                         sp->ttis[1].tt_abbrind = stdlen + 1;
 901                 }
 902         } else {
 903                 dstlen = 0;
 904                 sp->typecnt = 1;                /* only standard time */
 905                 sp->timecnt = 0;
 906                 sp->ttis[0].tt_gmtoff = -stdoffset;
 907                 sp->ttis[0].tt_isdst = 0;
 908                 sp->ttis[0].tt_abbrind = 0;
 909         }
 910         sp->charcnt = stdlen + 1;
 911         if (dstlen != 0)
 912                 sp->charcnt += dstlen + 1;
 913         if (sp->charcnt > sizeof sp->chars)
 914                 return -1;
 915         cp = sp->chars;
 916         (void) strncpy(cp, stdname, stdlen);
 917         cp += stdlen;
 918         *cp++ = '\0';
 919         if (dstlen != 0) {
 920                 (void) strncpy(cp, dstname, dstlen);
 921                 *(cp + dstlen) = '\0';
 922         }
 923         return 0;
 924 }
 925
 926 static void
 927 gmtload(sp)
 928 struct state * const    sp;
 929 {
 930         if (tzload(gmt, sp) != 0)
 931                 (void) tzparse(gmt, sp, TRUE);
 932 }
 933
 934 static void
 935 tzsetwall_basic(void)
 936 {
 937         if (lcl_is_set < 0)
 938                 return;
 939         lcl_is_set = -1;
 940
 941 #ifdef ALL_STATE
 942         if (lclptr == NULL) {
 943                 lclptr = (struct state *) malloc(sizeof *lclptr);
 944                 if (lclptr == NULL) {
 945                         settzname();    /* all we can do */
 946                         return;
 947                 }
 948         }
 949 #endif /* defined ALL_STATE */
 950         if (tzload((char *) NULL, lclptr) != 0)
 951                 gmtload(lclptr);
 952         settzname();
 953 }
 954
 955 void
 956 tzsetwall(void)
 957 {
 958         _MUTEX_LOCK(&lcl_mutex);
 959         tzsetwall_basic();
 960         _MUTEX_UNLOCK(&lcl_mutex);
 961 }
 962
 963 static void
 964 tzset_basic(void)
 965 {
 966         const char *    name;
 967
 968         name = getenv("TZ");
 969         if (name == NULL) {
 970                 tzsetwall_basic();
 971                 return;
 972         }
 973
 974         if (lcl_is_set > 0  &&  strcmp(lcl_TZname, name) == 0)
 975                 return;
 976         lcl_is_set = (strlen(name) < sizeof(lcl_TZname));
 977         if (lcl_is_set)
 978                 (void) strcpy(lcl_TZname, name);
 979
 980 #ifdef ALL_STATE
 981         if (lclptr == NULL) {
 982                 lclptr = (struct state *) malloc(sizeof *lclptr);
 983                 if (lclptr == NULL) {
 984                         settzname();    /* all we can do */
 985                         return;
 986                 }
 987         }
 988 #endif /* defined ALL_STATE */
 989         if (*name == '\0') {
 990                 /*
 991                 ** User wants it fast rather than right.
 992                 */
 993                 lclptr->leapcnt = 0;            /* so, we're off a little */
 994                 lclptr->timecnt = 0;
 995                 lclptr->ttis[0].tt_gmtoff = 0;
 996                 lclptr->ttis[0].tt_abbrind = 0;
 997                 (void) strcpy(lclptr->chars, gmt);
 998         } else if (tzload(name, lclptr) != 0)
 999                 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1000                         (void) gmtload(lclptr);
1001         settzname();
1002 }
1003
1004 void
1005 tzset(void)
1006 {
1007         _MUTEX_LOCK(&lcl_mutex);
1008         tzset_basic();
1009         _MUTEX_UNLOCK(&lcl_mutex);
1010 }
1011
1012 /*
1013 ** The easy way to behave "as if no library function calls" localtime
1014 ** is to not call it--so we drop its guts into "localsub", which can be
1015 ** freely called.  (And no, the PANS doesn't require the above behavior--
1016 ** but it *is* desirable.)
1017 **
1018 ** The unused offset argument is for the benefit of mktime variants.
1019 */
1020
1021 /*ARGSUSED*/
1022 static void
1023 localsub(timep, offset, tmp)
1024 const time_t * const    timep;
1025 const long              offset;
1026 struct tm * const       tmp;
1027 {
1028         struct state *          sp;
1029         const struct ttinfo *   ttisp;
1030         int                     i;
1031         const time_t                    t = *timep;
1032
1033         sp = lclptr;
1034 #ifdef ALL_STATE
1035         if (sp == NULL) {
1036                 gmtsub(timep, offset, tmp);
1037                 return;
1038         }
1039 #endif /* defined ALL_STATE */
1040         if (sp->timecnt == 0 || t < sp->ats[0]) {
1041                 i = 0;
1042                 while (sp->ttis[i].tt_isdst)
1043                         if (++i >= sp->typecnt) {
1044                                 i = 0;
1045                                 break;
1046                         }
1047         } else {
1048                 for (i = 1; i < sp->timecnt; ++i)
1049                         if (t < sp->ats[i])
1050                                 break;
1051                 i = sp->types[i - 1];
1052         }
1053         ttisp = &sp->ttis[i];
1054         /*
1055         ** To get (wrong) behavior that's compatible with System V Release 2.0
1056         ** you'd replace the statement below with
1057         **      t += ttisp->tt_gmtoff;
1058         **      timesub(&t, 0L, sp, tmp);
1059         */
1060         timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1061         tmp->tm_isdst = ttisp->tt_isdst;
1062         tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1063 #ifdef TM_ZONE
1064         tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1065 #endif /* defined TM_ZONE */
1066 }
1067
1068 struct tm *
1069 localtime_r(timep, p_tm)
1070 const time_t * const    timep;
1071 struct tm *p_tm;
1072 {
1073         _MUTEX_LOCK(&lcl_mutex);
1074         tzset_basic();
1075         localsub(timep, 0L, p_tm);
1076         _MUTEX_UNLOCK(&lcl_mutex);
1077         return(p_tm);
1078 }
1079
1080 struct tm *
1081 localtime(timep)
1082 const time_t * const    timep;
1083 {
1084         static pthread_mutex_t localtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1085         static pthread_key_t localtime_key = -1;
1086         struct tm *p_tm;
1087
1088         if (__isthreaded != 0) {
1089                 _pthread_mutex_lock(&localtime_mutex);
1090                 if (localtime_key < 0) {
1091                         if (_pthread_key_create(&localtime_key, free) < 0) {
1092                                 _pthread_mutex_unlock(&localtime_mutex);
1093                                 return(NULL);
1094                         }
1095                 }
1096                 _pthread_mutex_unlock(&localtime_mutex);
1097                 p_tm = _pthread_getspecific(localtime_key);
1098                 if (p_tm == NULL) {
1099                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1100                             == NULL)
1101                                 return(NULL);
1102                         _pthread_setspecific(localtime_key, p_tm);
1103                 }
1104                 _pthread_mutex_lock(&lcl_mutex);
1105                 tzset_basic();
1106                 localsub(timep, 0L, p_tm);
1107                 _pthread_mutex_unlock(&lcl_mutex);
1108                 return(p_tm);
1109         } else {
1110                 tzset_basic();
1111                 localsub(timep, 0L, &tm);
1112                 return(&tm);
1113         }
1114 }
1115
1116 /*
1117 ** gmtsub is to gmtime as localsub is to localtime.
1118 */
1119
1120 static void
1121 gmtsub(timep, offset, tmp)
1122 const time_t * const    timep;
1123 const long              offset;
1124 struct tm * const       tmp;
1125 {
1126         _MUTEX_LOCK(&gmt_mutex);
1127         if (!gmt_is_set) {
1128                 gmt_is_set = TRUE;
1129 #ifdef ALL_STATE
1130                 gmtptr = (struct state *) malloc(sizeof *gmtptr);
1131                 if (gmtptr != NULL)
1132 #endif /* defined ALL_STATE */
1133                         gmtload(gmtptr);
1134         }
1135         _MUTEX_UNLOCK(&gmt_mutex);
1136         timesub(timep, offset, gmtptr, tmp);
1137 #ifdef TM_ZONE
1138         /*
1139         ** Could get fancy here and deliver something such as
1140         ** "GMT+xxxx" or "GMT-xxxx" if offset is non-zero,
1141         ** but this is no time for a treasure hunt.
1142         */
1143         if (offset != 0)
1144                 tmp->TM_ZONE = wildabbr;
1145         else {
1146 #ifdef ALL_STATE
1147                 if (gmtptr == NULL)
1148                         tmp->TM_ZONE = gmt;
1149                 else    tmp->TM_ZONE = gmtptr->chars;
1150 #endif /* defined ALL_STATE */
1151 #ifndef ALL_STATE
1152                 tmp->TM_ZONE = gmtptr->chars;
1153 #endif /* State Farm */
1154         }
1155 #endif /* defined TM_ZONE */
1156 }
1157
1158 struct tm *
1159 gmtime(timep)
1160 const time_t * const    timep;
1161 {
1162         static pthread_mutex_t gmtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1163         static pthread_key_t gmtime_key = -1;
1164         struct tm *p_tm;
1165
1166         if (__isthreaded != 0) {
1167                 _pthread_mutex_lock(&gmtime_mutex);
1168                 if (gmtime_key < 0) {
1169                         if (_pthread_key_create(&gmtime_key, free) < 0) {
1170                                 _pthread_mutex_unlock(&gmtime_mutex);
1171                                 return(NULL);
1172                         }
1173                 }
1174                 _pthread_mutex_unlock(&gmtime_mutex);
1175                 /*
1176                  * Changed to follow POSIX.1 threads standard, which
1177                  * is what BSD currently has.
1178                  */
1179                 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1180                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1181                             == NULL) {
1182                                 return(NULL);
1183                         }
1184                         _pthread_setspecific(gmtime_key, p_tm);
1185                 }
1186                 gmtsub(timep, 0L, p_tm);
1187                 return(p_tm);
1188         }
1189         else {
1190                 gmtsub(timep, 0L, &tm);
1191                 return(&tm);
1192         }
1193 }
1194
1195 struct tm *
1196 gmtime_r(const time_t * timep, struct tm * tm)
1197 {
1198         gmtsub(timep, 0L, tm);
1199         return(tm);
1200 }
1201
1202 #ifdef STD_INSPIRED
1203
1204 struct tm *
1205 offtime(timep, offset)
1206 const time_t * const    timep;
1207 const long              offset;
1208 {
1209         gmtsub(timep, offset, &tm);
1210         return &tm;
1211 }
1212
1213 #endif /* defined STD_INSPIRED */
1214
1215 static void
1216 timesub(timep, offset, sp, tmp)
1217 const time_t * const                    timep;
1218 const long                              offset;
1219 const struct state * const      sp;
1220 struct tm * const               tmp;
1221 {
1222         const struct lsinfo *   lp;
1223         long                    days;
1224         long                    rem;
1225         int                     y;
1226         int                     yleap;
1227         const int *             ip;
1228         long                    corr;
1229         int                     hit;
1230         int                     i;
1231
1232         corr = 0;
1233         hit = 0;
1234 #ifdef ALL_STATE
1235         i = (sp == NULL) ? 0 : sp->leapcnt;
1236 #endif /* defined ALL_STATE */
1237 #ifndef ALL_STATE
1238         i = sp->leapcnt;
1239 #endif /* State Farm */
1240         while (--i >= 0) {
1241                 lp = &sp->lsis[i];
1242                 if (*timep >= lp->ls_trans) {
1243                         if (*timep == lp->ls_trans) {
1244                                 hit = ((i == 0 && lp->ls_corr > 0) ||
1245                                         lp->ls_corr > sp->lsis[i - 1].ls_corr);
1246                                 if (hit)
1247                                         while (i > 0 &&
1248                                                 sp->lsis[i].ls_trans ==
1249                                                 sp->lsis[i - 1].ls_trans + 1 &&
1250                                                 sp->lsis[i].ls_corr ==
1251                                                 sp->lsis[i - 1].ls_corr + 1) {
1252                                                         ++hit;
1253                                                         --i;
1254                                         }
1255                         }
1256                         corr = lp->ls_corr;
1257                         break;
1258                 }
1259         }
1260         days = *timep / SECSPERDAY;
1261         rem = *timep % SECSPERDAY;
1262 #ifdef mc68k
1263         if (*timep == 0x80000000) {
1264                 /*
1265                 ** A 3B1 muffs the division on the most negative number.
1266                 */
1267                 days = -24855;
1268                 rem = -11648;
1269         }
1270 #endif /* defined mc68k */
1271         rem += (offset - corr);
1272         while (rem < 0) {
1273                 rem += SECSPERDAY;
1274                 --days;
1275         }
1276         while (rem >= SECSPERDAY) {
1277                 rem -= SECSPERDAY;
1278                 ++days;
1279         }
1280         tmp->tm_hour = (int) (rem / SECSPERHOUR);
1281         rem = rem % SECSPERHOUR;
1282         tmp->tm_min = (int) (rem / SECSPERMIN);
1283         /*
1284         ** A positive leap second requires a special
1285         ** representation.  This uses "... ??:59:60" et seq.
1286         */
1287         tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1288         tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
1289         if (tmp->tm_wday < 0)
1290                 tmp->tm_wday += DAYSPERWEEK;
1291         y = EPOCH_YEAR;
1292 #define LEAPS_THRU_END_OF(y)    ((y) / 4 - (y) / 100 + (y) / 400)
1293         while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
1294                 int     newy;
1295
1296                 newy = y + days / DAYSPERNYEAR;
1297                 if (days < 0)
1298                         --newy;
1299                 days -= (newy - y) * DAYSPERNYEAR +
1300                         LEAPS_THRU_END_OF(newy - 1) -
1301                         LEAPS_THRU_END_OF(y - 1);
1302                 y = newy;
1303         }
1304         tmp->tm_year = y - TM_YEAR_BASE;
1305         tmp->tm_yday = (int) days;
1306         ip = mon_lengths[yleap];
1307         for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
1308                 days = days - (long) ip[tmp->tm_mon];
1309         tmp->tm_mday = (int) (days + 1);
1310         tmp->tm_isdst = 0;
1311 #ifdef TM_GMTOFF
1312         tmp->TM_GMTOFF = offset;
1313 #endif /* defined TM_GMTOFF */
1314 }
1315
1316 char *
1317 ctime(timep)
1318 const time_t * const    timep;
1319 {
1320 /*
1321 ** Section 4.12.3.2 of X3.159-1989 requires that
1322 **      The ctime funciton converts the calendar time pointed to by timer
1323 **      to local time in the form of a string.  It is equivalent to
1324 **              asctime(localtime(timer))
1325 */
1326         return asctime(localtime(timep));
1327 }
1328
1329 char *
1330 ctime_r(timep, buf)
1331 const time_t * const    timep;
1332 char *buf;
1333 {
1334         struct tm tm;
1335         return asctime_r(localtime_r(timep, &tm), buf);
1336 }
1337
1338 /*
1339 ** Adapted from code provided by Robert Elz, who writes:
1340 **      The "best" way to do mktime I think is based on an idea of Bob
1341 **      Kridle's (so its said...) from a long time ago.
1342 **      [kridle@xinet.com as of 1996-01-16.]
1343 **      It does a binary search of the time_t space.  Since time_t's are
1344 **      just 32 bits, its a max of 32 iterations (even at 64 bits it
1345 **      would still be very reasonable).
1346 */
1347
1348 #ifndef WRONG
1349 #define WRONG   (-1)
1350 #endif /* !defined WRONG */
1351
1352 /*
1353 ** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
1354 */
1355
1356 static int
1357 increment_overflow(number, delta)
1358 int *   number;
1359 int     delta;
1360 {
1361         int     number0;
1362
1363         number0 = *number;
1364         *number += delta;
1365         return (*number < number0) != (delta < 0);
1366 }
1367
1368 static int
1369 normalize_overflow(tensptr, unitsptr, base)
1370 int * const     tensptr;
1371 int * const     unitsptr;
1372 const int       base;
1373 {
1374         int     tensdelta;
1375
1376         tensdelta = (*unitsptr >= 0) ?
1377                 (*unitsptr / base) :
1378                 (-1 - (-1 - *unitsptr) / base);
1379         *unitsptr -= tensdelta * base;
1380         return increment_overflow(tensptr, tensdelta);
1381 }
1382
1383 static int
1384 tmcomp(atmp, btmp)
1385 const struct tm * const atmp;
1386 const struct tm * const btmp;
1387 {
1388         int     result;
1389
1390         if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1391                 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1392                 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1393                 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1394                 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1395                         result = atmp->tm_sec - btmp->tm_sec;
1396         return result;
1397 }
1398
1399 static time_t
1400 time2(tmp, funcp, offset, okayp)
1401 struct tm * const       tmp;
1402 void (* const           funcp)(const time_t*, long, struct tm*);
1403 const long              offset;
1404 int * const             okayp;
1405 {
1406         const struct state *    sp;
1407         int                     dir;
1408         int                     bits;
1409         int                     i, j ;
1410         int                     saved_seconds;
1411         time_t                          newt;
1412         time_t                          t;
1413         struct tm                       yourtm, mytm;
1414
1415         *okayp = FALSE;
1416         yourtm = *tmp;
1417         if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1418                 return WRONG;
1419         if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1420                 return WRONG;
1421         if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
1422                 return WRONG;
1423         /*
1424         ** Turn yourtm.tm_year into an actual year number for now.
1425         ** It is converted back to an offset from TM_YEAR_BASE later.
1426         */
1427         if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
1428                 return WRONG;
1429         while (yourtm.tm_mday <= 0) {
1430                 if (increment_overflow(&yourtm.tm_year, -1))
1431                         return WRONG;
1432                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1433                 yourtm.tm_mday += year_lengths[isleap(i)];
1434         }
1435         while (yourtm.tm_mday > DAYSPERLYEAR) {
1436                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1437                 yourtm.tm_mday -= year_lengths[isleap(i)];
1438                 if (increment_overflow(&yourtm.tm_year, 1))
1439                         return WRONG;
1440         }
1441         for ( ; ; ) {
1442                 i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
1443                 if (yourtm.tm_mday <= i)
1444                         break;
1445                 yourtm.tm_mday -= i;
1446                 if (++yourtm.tm_mon >= MONSPERYEAR) {
1447                         yourtm.tm_mon = 0;
1448                         if (increment_overflow(&yourtm.tm_year, 1))
1449                                 return WRONG;
1450                 }
1451         }
1452         if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
1453                 return WRONG;
1454         if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1455                 saved_seconds = 0;
1456         else if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
1457                 /*
1458                 ** We can't set tm_sec to 0, because that might push the
1459                 ** time below the minimum representable time.
1460                 ** Set tm_sec to 59 instead.
1461                 ** This assumes that the minimum representable time is
1462                 ** not in the same minute that a leap second was deleted from,
1463                 ** which is a safer assumption than using 58 would be.
1464                 */
1465                 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1466                         return WRONG;
1467                 saved_seconds = yourtm.tm_sec;
1468                 yourtm.tm_sec = SECSPERMIN - 1;
1469         } else {
1470                 saved_seconds = yourtm.tm_sec;
1471                 yourtm.tm_sec = 0;
1472         }
1473         /*
1474         ** Divide the search space in half
1475         ** (this works whether time_t is signed or unsigned).
1476         */
1477         bits = TYPE_BIT(time_t) - 1;
1478         /*
1479         ** If time_t is signed, then 0 is just above the median,
1480         ** assuming two's complement arithmetic.
1481         ** If time_t is unsigned, then (1 << bits) is just above the median.
1482         */
1483         t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
1484         for ( ; ; ) {
1485                 (*funcp)(&t, offset, &mytm);
1486                 dir = tmcomp(&mytm, &yourtm);
1487                 if (dir != 0) {
1488                         if (bits-- < 0)
1489                                 return WRONG;
1490                         if (bits < 0)
1491                                 --t; /* may be needed if new t is minimal */
1492                         else if (dir > 0)
1493                                 t -= ((time_t) 1) << bits;
1494                         else    t += ((time_t) 1) << bits;
1495                         continue;
1496                 }
1497                 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1498                         break;
1499                 /*
1500                 ** Right time, wrong type.
1501                 ** Hunt for right time, right type.
1502                 ** It's okay to guess wrong since the guess
1503                 ** gets checked.
1504                 */
1505                 /*
1506                 ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1507                 */
1508                 sp = (const struct state *)
1509                         (((void *) funcp == (void *) localsub) ?
1510                         lclptr : gmtptr);
1511 #ifdef ALL_STATE
1512                 if (sp == NULL)
1513                         return WRONG;
1514 #endif /* defined ALL_STATE */
1515                 for (i = sp->typecnt - 1; i >= 0; --i) {
1516                         if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1517                                 continue;
1518                         for (j = sp->typecnt - 1; j >= 0; --j) {
1519                                 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1520                                         continue;
1521                                 newt = t + sp->ttis[j].tt_gmtoff -
1522                                         sp->ttis[i].tt_gmtoff;
1523                                 (*funcp)(&newt, offset, &mytm);
1524                                 if (tmcomp(&mytm, &yourtm) != 0)
1525                                         continue;
1526                                 if (mytm.tm_isdst != yourtm.tm_isdst)
1527                                         continue;
1528                                 /*
1529                                 ** We have a match.
1530                                 */
1531                                 t = newt;
1532                                 goto label;
1533                         }
1534                 }
1535                 return WRONG;
1536         }
1537 label:
1538         newt = t + saved_seconds;
1539         if ((newt < t) != (saved_seconds < 0))
1540                 return WRONG;
1541         t = newt;
1542         (*funcp)(&t, offset, tmp);
1543         *okayp = TRUE;
1544         return t;
1545 }
1546
1547 static time_t
1548 time1(tmp, funcp, offset)
1549 struct tm * const       tmp;
1550 void (* const           funcp)(const time_t *, long, struct tm *);
1551 const long              offset;
1552 {
1553         time_t                  t;
1554         const struct state *    sp;
1555         int                     samei, otheri;
1556         int                             okay;
1557
1558         if (tmp->tm_isdst > 1)
1559                 tmp->tm_isdst = 1;
1560         t = time2(tmp, funcp, offset, &okay);
1561 #ifdef PCTS
1562         /*
1563         ** PCTS code courtesy Grant Sullivan (grant@osf.org).
1564         */
1565         if (okay)
1566                 return t;
1567         if (tmp->tm_isdst < 0)
1568                 tmp->tm_isdst = 0;      /* reset to std and try again */
1569 #endif /* defined PCTS */
1570 #ifndef PCTS
1571         if (okay || tmp->tm_isdst < 0)
1572                 return t;
1573 #endif /* !defined PCTS */
1574         /*
1575         ** We're supposed to assume that somebody took a time of one type
1576         ** and did some math on it that yielded a "struct tm" that's bad.
1577         ** We try to divine the type they started from and adjust to the
1578         ** type they need.
1579         */
1580         /*
1581         ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1582         */
1583         sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
1584                 lclptr : gmtptr);
1585 #ifdef ALL_STATE
1586         if (sp == NULL)
1587                 return WRONG;
1588 #endif /* defined ALL_STATE */
1589         for (samei = sp->typecnt - 1; samei >= 0; --samei) {
1590                 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1591                         continue;
1592                 for (otheri = sp->typecnt - 1; otheri >= 0; --otheri) {
1593                         if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1594                                 continue;
1595                         tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1596                                         sp->ttis[samei].tt_gmtoff;
1597                         tmp->tm_isdst = !tmp->tm_isdst;
1598                         t = time2(tmp, funcp, offset, &okay);
1599                         if (okay)
1600                                 return t;
1601                         tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1602                                         sp->ttis[samei].tt_gmtoff;
1603                         tmp->tm_isdst = !tmp->tm_isdst;
1604                 }
1605         }
1606         return WRONG;
1607 }
1608
1609 time_t
1610 mktime(tmp)
1611 struct tm * const       tmp;
1612 {
1613         time_t mktime_return_value;
1614         _MUTEX_LOCK(&lcl_mutex);
1615         tzset_basic();
1616         mktime_return_value = time1(tmp, localsub, 0L);
1617         _MUTEX_UNLOCK(&lcl_mutex);
1618         return(mktime_return_value);
1619 }
1620
1621 #ifdef STD_INSPIRED
1622
1623 time_t
1624 timelocal(tmp)
1625 struct tm * const       tmp;
1626 {
1627         tmp->tm_isdst = -1;     /* in case it wasn't initialized */
1628         return mktime(tmp);
1629 }
1630
1631 time_t
1632 timegm(tmp)
1633 struct tm * const       tmp;
1634 {
1635         tmp->tm_isdst = 0;
1636         return time1(tmp, gmtsub, 0L);
1637 }
1638
1639 time_t
1640 timeoff(tmp, offset)
1641 struct tm * const       tmp;
1642 const long              offset;
1643 {
1644         tmp->tm_isdst = 0;
1645         return time1(tmp, gmtsub, offset);
1646 }
1647
1648 #endif /* defined STD_INSPIRED */
1649
1650 #ifdef CMUCS
1651
1652 /*
1653 ** The following is supplied for compatibility with
1654 ** previous versions of the CMUCS runtime library.
1655 */
1656
1657 long
1658 gtime(tmp)
1659 struct tm * const       tmp;
1660 {
1661         const time_t    t = mktime(tmp);
1662
1663         if (t == WRONG)
1664                 return -1;
1665         return t;
1666 }
1667
1668 #endif /* defined CMUCS */
1669
1670 /*
1671 ** XXX--is the below the right way to conditionalize??
1672 */
1673
1674 #ifdef STD_INSPIRED
1675
1676 /*
1677 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1678 ** shall correspond to "Wed Dec 31 23:59:59 GMT 1986", which
1679 ** is not the case if we are accounting for leap seconds.
1680 ** So, we provide the following conversion routines for use
1681 ** when exchanging timestamps with POSIX conforming systems.
1682 */
1683
1684 static long
1685 leapcorr(timep)
1686 time_t *        timep;
1687 {
1688         struct state *          sp;
1689         struct lsinfo * lp;
1690         int                     i;
1691
1692         sp = lclptr;
1693         i = sp->leapcnt;
1694         while (--i >= 0) {
1695                 lp = &sp->lsis[i];
1696                 if (*timep >= lp->ls_trans)
1697                         return lp->ls_corr;
1698         }
1699         return 0;
1700 }
1701
1702 time_t
1703 time2posix(t)
1704 time_t  t;
1705 {
1706         tzset();
1707         return t - leapcorr(&t);
1708 }
1709
1710 time_t
1711 posix2time(t)
1712 time_t  t;
1713 {
1714         time_t  x;
1715         time_t  y;
1716
1717         tzset();
1718         /*
1719         ** For a positive leap second hit, the result
1720         ** is not unique.  For a negative leap second
1721         ** hit, the corresponding time doesn't exist,
1722         ** so we return an adjacent second.
1723         */
1724         x = t + leapcorr(&t);
1725         y = x - leapcorr(&x);
1726         if (y < t) {
1727                 do {
1728                         x++;
1729                         y = x - leapcorr(&x);
1730                 } while (y < t);
1731                 if (t != y)
1732                         return x - 1;
1733         } else if (y > t) {
1734                 do {
1735                         --x;
1736                         y = x - leapcorr(&x);
1737                 } while (y > t);
1738                 if (t != y)
1739                         return x + 1;
1740         }
1741         return x;
1742 }
1743
1744 #endif /* defined STD_INSPIRED */