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 1.6 2005/12/04 23:41:06 swildner 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 <time.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, int max);
 129 static const char *     getsecs(const char * strp, long * secsp);
 130 static const char *     getoffset(const char * strp, long * offsetp);
 131 static const char *     getrule(const char * strp, struct rule * rulep);
 132 static void             gmtload(struct state * sp);
 133 static void             gmtsub(const time_t * timep, long offset,
 134                                 struct tm * tmp);
 135 static void             localsub(const time_t * timep, long offset,
 136                                 struct tm * tmp);
 137 static int              increment_overflow(int * number, int delta);
 138 static int              normalize_overflow(int * tensptr, int * unitsptr,
 139                                 int base);
 140 static void             settzname(void);
 141 static time_t           time1(struct tm * tmp,
 142                                 void(*funcp)(const time_t *, long, struct tm *),
 143                                 long offset);
 144 static time_t           time2(struct tm *tmp,
 145                                 void(*funcp)(const time_t *, long, struct tm *),
 146                                 long offset, int * okayp);
 147 static void             timesub(const time_t * timep, long offset,
 148                                 const struct state * sp, struct tm * tmp);
 149 static int              tmcomp(const struct tm * atmp,
 150                                 const struct tm * btmp);
 151 static time_t           transtime(time_t janfirst, int year,
 152                                 const struct rule * rulep, long offset);
 153 static int              tzload(const char * name, struct state * sp);
 154 static int              tzparse(const char * name, struct state * sp,
 155                                 int lastditch);
 156
 157 #ifdef ALL_STATE
 158 static struct state *   lclptr;
 159 static struct state *   gmtptr;
 160 #endif /* defined ALL_STATE */
 161
 162 #ifndef ALL_STATE
 163 static struct state     lclmem;
 164 static struct state     gmtmem;
 165 #define lclptr          (&lclmem)
 166 #define gmtptr          (&gmtmem)
 167 #endif /* State Farm */
 168
 169 #ifndef TZ_STRLEN_MAX
 170 #define TZ_STRLEN_MAX 255
 171 #endif /* !defined TZ_STRLEN_MAX */
 172
 173 static char             lcl_TZname[TZ_STRLEN_MAX + 1];
 174 static int              lcl_is_set;
 175 static int              gmt_is_set;
 176 static pthread_mutex_t  lcl_mutex = PTHREAD_MUTEX_INITIALIZER;
 177 static pthread_mutex_t  gmt_mutex = PTHREAD_MUTEX_INITIALIZER;
 178
 179 char *                  tzname[2] = {
 180         wildabbr,
 181         wildabbr
 182 };
 183
 184 /*
 185 ** Section 4.12.3 of X3.159-1989 requires that
 186 **      Except for the strftime function, these functions [asctime,
 187 **      ctime, gmtime, localtime] return values in one of two static
 188 **      objects: a broken-down time structure and an array of char.
 189 ** Thanks to Paul Eggert (eggert@twinsun.com) for noting this.
 190 */
 191
 192 static struct tm        tm;
 193
 194 #ifdef USG_COMPAT
 195 time_t                  timezone = 0;
 196 int                     daylight = 0;
 197 #endif /* defined USG_COMPAT */
 198
 199 #ifdef ALTZONE
 200 time_t                  altzone = 0;
 201 #endif /* defined ALTZONE */
 202
 203 static long
 204 detzcode(const char * const codep)
 205 {
 206         long    result;
 207         int     i;
 208
 209         result = (codep[0] & 0x80) ? ~0L : 0L;
 210         for (i = 0; i < 4; ++i)
 211                 result = (result << 8) | (codep[i] & 0xff);
 212         return result;
 213 }
 214
 215 static void
 216 settzname(void)
 217 {
 218         struct state *  sp = lclptr;
 219         int                     i;
 220
 221         tzname[0] = wildabbr;
 222         tzname[1] = wildabbr;
 223 #ifdef USG_COMPAT
 224         daylight = 0;
 225         timezone = 0;
 226 #endif /* defined USG_COMPAT */
 227 #ifdef ALTZONE
 228         altzone = 0;
 229 #endif /* defined ALTZONE */
 230 #ifdef ALL_STATE
 231         if (sp == NULL) {
 232                 tzname[0] = tzname[1] = gmt;
 233                 return;
 234         }
 235 #endif /* defined ALL_STATE */
 236         for (i = 0; i < sp->typecnt; ++i) {
 237                 const struct ttinfo * const     ttisp = &sp->ttis[i];
 238
 239                 tzname[ttisp->tt_isdst] =
 240                         &sp->chars[ttisp->tt_abbrind];
 241 #ifdef USG_COMPAT
 242                 if (ttisp->tt_isdst)
 243                         daylight = 1;
 244                 if (i == 0 || !ttisp->tt_isdst)
 245                         timezone = -(ttisp->tt_gmtoff);
 246 #endif /* defined USG_COMPAT */
 247 #ifdef ALTZONE
 248                 if (i == 0 || ttisp->tt_isdst)
 249                         altzone = -(ttisp->tt_gmtoff);
 250 #endif /* defined ALTZONE */
 251         }
 252         /*
 253         ** And to get the latest zone names into tzname. . .
 254         */
 255         for (i = 0; i < sp->timecnt; ++i) {
 256                 const struct ttinfo * const     ttisp =
 257                                                         &sp->ttis[
 258                                                                 sp->types[i]];
 259
 260                 tzname[ttisp->tt_isdst] =
 261                         &sp->chars[ttisp->tt_abbrind];
 262         }
 263 }
 264
 265 static int
 266 tzload(const char *name, struct state * const sp)
 267 {
 268         const char *    p;
 269         int             i;
 270         int             fid;
 271
 272         /* XXX The following is from OpenBSD, and I'm not sure it is correct */
 273         if (name != NULL && issetugid() != 0)
 274                 if ((name[0] == ':' && name[1] == '/') ||
 275                     name[0] == '/' || strchr(name, '.'))
 276                         name = NULL;
 277         if (name == NULL && (name = TZDEFAULT) == NULL)
 278                 return -1;
 279         {
 280                 int     doaccess;
 281                 struct stat     stab;
 282                 /*
 283                 ** Section 4.9.1 of the C standard says that
 284                 ** "FILENAME_MAX expands to an integral constant expression
 285                 ** that is the size needed for an array of char large enough
 286                 ** to hold the longest file name string that the implementation
 287                 ** guarantees can be opened."
 288                 */
 289                 char            fullname[FILENAME_MAX + 1];
 290
 291                 if (name[0] == ':')
 292                         ++name;
 293                 doaccess = name[0] == '/';
 294                 if (!doaccess) {
 295                         if ((p = TZDIR) == NULL)
 296                                 return -1;
 297                         if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
 298                                 return -1;
 299                         strcpy(fullname, p);
 300                         strcat(fullname, "/");
 301                         strcat(fullname, name);
 302                         /*
 303                         ** Set doaccess if '.' (as in "../") shows up in name.
 304                         */
 305                         if (strchr(name, '.') != NULL)
 306                                 doaccess = TRUE;
 307                         name = fullname;
 308                 }
 309                 if (doaccess && access(name, R_OK) != 0)
 310                         return -1;
 311                 if ((fid = _open(name, OPEN_MODE)) == -1)
 312                         return -1;
 313                 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
 314                         _close(fid);
 315                         return -1;
 316                 }
 317         }
 318         {
 319                 struct tzhead * tzhp;
 320                 char            buf[sizeof *sp + sizeof *tzhp];
 321                 int             ttisstdcnt;
 322                 int             ttisgmtcnt;
 323
 324                 i = _read(fid, buf, sizeof buf);
 325                 if (_close(fid) != 0)
 326                         return -1;
 327                 p = buf;
 328                 p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
 329                 ttisstdcnt = (int) detzcode(p);
 330                 p += 4;
 331                 ttisgmtcnt = (int) detzcode(p);
 332                 p += 4;
 333                 sp->leapcnt = (int) detzcode(p);
 334                 p += 4;
 335                 sp->timecnt = (int) detzcode(p);
 336                 p += 4;
 337                 sp->typecnt = (int) detzcode(p);
 338                 p += 4;
 339                 sp->charcnt = (int) detzcode(p);
 340                 p += 4;
 341                 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
 342                         sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
 343                         sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
 344                         sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
 345                         (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
 346                         (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
 347                                 return -1;
 348                 if (i - (p - buf) < sp->timecnt * 4 +   /* ats */
 349                         sp->timecnt +                   /* types */
 350                         sp->typecnt * (4 + 2) +         /* ttinfos */
 351                         sp->charcnt +                   /* chars */
 352                         sp->leapcnt * (4 + 4) +         /* lsinfos */
 353                         ttisstdcnt +                    /* ttisstds */
 354                         ttisgmtcnt)                     /* ttisgmts */
 355                                 return -1;
 356                 for (i = 0; i < sp->timecnt; ++i) {
 357                         sp->ats[i] = detzcode(p);
 358                         p += 4;
 359                 }
 360                 for (i = 0; i < sp->timecnt; ++i) {
 361                         sp->types[i] = (unsigned char) *p++;
 362                         if (sp->types[i] >= sp->typecnt)
 363                                 return -1;
 364                 }
 365                 for (i = 0; i < sp->typecnt; ++i) {
 366                         struct ttinfo * ttisp;
 367
 368                         ttisp = &sp->ttis[i];
 369                         ttisp->tt_gmtoff = detzcode(p);
 370                         p += 4;
 371                         ttisp->tt_isdst = (unsigned char) *p++;
 372                         if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
 373                                 return -1;
 374                         ttisp->tt_abbrind = (unsigned char) *p++;
 375                         if (ttisp->tt_abbrind < 0 ||
 376                                 ttisp->tt_abbrind > sp->charcnt)
 377                                         return -1;
 378                 }
 379                 for (i = 0; i < sp->charcnt; ++i)
 380                         sp->chars[i] = *p++;
 381                 sp->chars[i] = '\0';    /* ensure '\0' at end */
 382                 for (i = 0; i < sp->leapcnt; ++i) {
 383                         struct lsinfo * lsisp;
 384
 385                         lsisp = &sp->lsis[i];
 386                         lsisp->ls_trans = detzcode(p);
 387                         p += 4;
 388                         lsisp->ls_corr = detzcode(p);
 389                         p += 4;
 390                 }
 391                 for (i = 0; i < sp->typecnt; ++i) {
 392                         struct ttinfo * ttisp;
 393
 394                         ttisp = &sp->ttis[i];
 395                         if (ttisstdcnt == 0)
 396                                 ttisp->tt_ttisstd = FALSE;
 397                         else {
 398                                 ttisp->tt_ttisstd = *p++;
 399                                 if (ttisp->tt_ttisstd != TRUE &&
 400                                         ttisp->tt_ttisstd != FALSE)
 401                                                 return -1;
 402                         }
 403                 }
 404                 for (i = 0; i < sp->typecnt; ++i) {
 405                         struct ttinfo * ttisp;
 406
 407                         ttisp = &sp->ttis[i];
 408                         if (ttisgmtcnt == 0)
 409                                 ttisp->tt_ttisgmt = FALSE;
 410                         else {
 411                                 ttisp->tt_ttisgmt = *p++;
 412                                 if (ttisp->tt_ttisgmt != TRUE &&
 413                                         ttisp->tt_ttisgmt != FALSE)
 414                                                 return -1;
 415                         }
 416                 }
 417         }
 418         return 0;
 419 }
 420
 421 static const int        mon_lengths[2][MONSPERYEAR] = {
 422         { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 423         { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 424 };
 425
 426 static const int        year_lengths[2] = {
 427         DAYSPERNYEAR, DAYSPERLYEAR
 428 };
 429
 430 /*
 431 ** Given a pointer into a time zone string, scan until a character that is not
 432 ** a valid character in a zone name is found.  Return a pointer to that
 433 ** character.
 434 */
 435
 436 static const char *
 437 getzname(const char *strp)
 438 {
 439         char    c;
 440
 441         while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
 442                 c != '+')
 443                         ++strp;
 444         return strp;
 445 }
 446
 447 /*
 448 ** Given a pointer into a time zone string, extract a number from that string.
 449 ** Check that the number is within a specified range; if it is not, return
 450 ** NULL.
 451 ** Otherwise, return a pointer to the first character not part of the number.
 452 */
 453
 454 static const char *
 455 getnum(const char *strp, int * const nump, const int min, const int max)
 456 {
 457         char    c;
 458         int     num;
 459
 460         if (strp == NULL || !is_digit(c = *strp))
 461                 return NULL;
 462         num = 0;
 463         do {
 464                 num = num * 10 + (c - '0');
 465                 if (num > max)
 466                         return NULL;    /* illegal value */
 467                 c = *++strp;
 468         } while (is_digit(c));
 469         if (num < min)
 470                 return NULL;            /* illegal value */
 471         *nump = num;
 472         return strp;
 473 }
 474
 475 /*
 476 ** Given a pointer into a time zone string, extract a number of seconds,
 477 ** in hh[:mm[:ss]] form, from the string.
 478 ** If any error occurs, return NULL.
 479 ** Otherwise, return a pointer to the first character not part of the number
 480 ** of seconds.
 481 */
 482
 483 static const char *
 484 getsecs(const char *strp, long * const secsp)
 485 {
 486         int     num;
 487
 488         /*
 489         ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
 490         ** "M10.4.6/26", which does not conform to Posix,
 491         ** but which specifies the equivalent of
 492         ** ``02:00 on the first Sunday on or after 23 Oct''.
 493         */
 494         strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
 495         if (strp == NULL)
 496                 return NULL;
 497         *secsp = num * (long) SECSPERHOUR;
 498         if (*strp == ':') {
 499                 ++strp;
 500                 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
 501                 if (strp == NULL)
 502                         return NULL;
 503                 *secsp += num * SECSPERMIN;
 504                 if (*strp == ':') {
 505                         ++strp;
 506                         /* `SECSPERMIN' allows for leap seconds.  */
 507                         strp = getnum(strp, &num, 0, SECSPERMIN);
 508                         if (strp == NULL)
 509                                 return NULL;
 510                         *secsp += num;
 511                 }
 512         }
 513         return strp;
 514 }
 515
 516 /*
 517 ** Given a pointer into a time zone string, extract an offset, in
 518 ** [+-]hh[:mm[:ss]] form, from the string.
 519 ** If any error occurs, return NULL.
 520 ** Otherwise, return a pointer to the first character not part of the time.
 521 */
 522
 523 static const char *
 524 getoffset(const char *strp, long * const offsetp)
 525 {
 526         int     neg = 0;
 527
 528         if (*strp == '-') {
 529                 neg = 1;
 530                 ++strp;
 531         } else if (*strp == '+')
 532                 ++strp;
 533         strp = getsecs(strp, offsetp);
 534         if (strp == NULL)
 535                 return NULL;            /* illegal time */
 536         if (neg)
 537                 *offsetp = -*offsetp;
 538         return strp;
 539 }
 540
 541 /*
 542 ** Given a pointer into a time zone string, extract a rule in the form
 543 ** date[/time].  See POSIX section 8 for the format of "date" and "time".
 544 ** If a valid rule is not found, return NULL.
 545 ** Otherwise, return a pointer to the first character not part of the rule.
 546 */
 547
 548 static const char *
 549 getrule(const char *strp, struct rule * const rulep)
 550 {
 551         if (*strp == 'J') {
 552                 /*
 553                 ** Julian day.
 554                 */
 555                 rulep->r_type = JULIAN_DAY;
 556                 ++strp;
 557                 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
 558         } else if (*strp == 'M') {
 559                 /*
 560                 ** Month, week, day.
 561                 */
 562                 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
 563                 ++strp;
 564                 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
 565                 if (strp == NULL)
 566                         return NULL;
 567                 if (*strp++ != '.')
 568                         return NULL;
 569                 strp = getnum(strp, &rulep->r_week, 1, 5);
 570                 if (strp == NULL)
 571                         return NULL;
 572                 if (*strp++ != '.')
 573                         return NULL;
 574                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
 575         } else if (is_digit(*strp)) {
 576                 /*
 577                 ** Day of year.
 578                 */
 579                 rulep->r_type = DAY_OF_YEAR;
 580                 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
 581         } else  return NULL;            /* invalid format */
 582         if (strp == NULL)
 583                 return NULL;
 584         if (*strp == '/') {
 585                 /*
 586                 ** Time specified.
 587                 */
 588                 ++strp;
 589                 strp = getsecs(strp, &rulep->r_time);
 590         } else  rulep->r_time = 2 * SECSPERHOUR;        /* default = 2:00:00 */
 591         return strp;
 592 }
 593
 594 /*
 595 ** Given the Epoch-relative time of January 1, 00:00:00 GMT, in a year, the
 596 ** year, a rule, and the offset from GMT at the time that rule takes effect,
 597 ** calculate the Epoch-relative time that rule takes effect.
 598 */
 599
 600 static time_t
 601 transtime(const time_t janfirst, const int year,
 602           const struct rule * const rulep, const long offset)
 603 {
 604         int     leapyear;
 605         time_t  value;
 606         int     i;
 607         int             d, m1, yy0, yy1, yy2, dow;
 608
 609         INITIALIZE(value);
 610         leapyear = isleap(year);
 611         switch (rulep->r_type) {
 612
 613         case JULIAN_DAY:
 614                 /*
 615                 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
 616                 ** years.
 617                 ** In non-leap years, or if the day number is 59 or less, just
 618                 ** add SECSPERDAY times the day number-1 to the time of
 619                 ** January 1, midnight, to get the day.
 620                 */
 621                 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
 622                 if (leapyear && rulep->r_day >= 60)
 623                         value += SECSPERDAY;
 624                 break;
 625
 626         case DAY_OF_YEAR:
 627                 /*
 628                 ** n - day of year.
 629                 ** Just add SECSPERDAY times the day number to the time of
 630                 ** January 1, midnight, to get the day.
 631                 */
 632                 value = janfirst + rulep->r_day * SECSPERDAY;
 633                 break;
 634
 635         case MONTH_NTH_DAY_OF_WEEK:
 636                 /*
 637                 ** Mm.n.d - nth "dth day" of month m.
 638                 */
 639                 value = janfirst;
 640                 for (i = 0; i < rulep->r_mon - 1; ++i)
 641                         value += mon_lengths[leapyear][i] * SECSPERDAY;
 642
 643                 /*
 644                 ** Use Zeller's Congruence to get day-of-week of first day of
 645                 ** month.
 646                 */
 647                 m1 = (rulep->r_mon + 9) % 12 + 1;
 648                 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
 649                 yy1 = yy0 / 100;
 650                 yy2 = yy0 % 100;
 651                 dow = ((26 * m1 - 2) / 10 +
 652                         1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
 653                 if (dow < 0)
 654                         dow += DAYSPERWEEK;
 655
 656                 /*
 657                 ** "dow" is the day-of-week of the first day of the month.  Get
 658                 ** the day-of-month (zero-origin) of the first "dow" day of the
 659                 ** month.
 660                 */
 661                 d = rulep->r_day - dow;
 662                 if (d < 0)
 663                         d += DAYSPERWEEK;
 664                 for (i = 1; i < rulep->r_week; ++i) {
 665                         if (d + DAYSPERWEEK >=
 666                                 mon_lengths[leapyear][rulep->r_mon - 1])
 667                                         break;
 668                         d += DAYSPERWEEK;
 669                 }
 670
 671                 /*
 672                 ** "d" is the day-of-month (zero-origin) of the day we want.
 673                 */
 674                 value += d * SECSPERDAY;
 675                 break;
 676         }
 677
 678         /*
 679         ** "value" is the Epoch-relative time of 00:00:00 GMT on the day in
 680         ** question.  To get the Epoch-relative time of the specified local
 681         ** time on that day, add the transition time and the current offset
 682         ** from GMT.
 683         */
 684         return value + rulep->r_time + offset;
 685 }
 686
 687 /*
 688 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
 689 ** appropriate.
 690 */
 691
 692 static int
 693 tzparse(const char *name, struct state * const sp, const int lastditch)
 694 {
 695         const char *                    stdname;
 696         const char *                    dstname;
 697         size_t                          stdlen;
 698         size_t                          dstlen;
 699         long                            stdoffset;
 700         long                            dstoffset;
 701         time_t *                atp;
 702         unsigned char * typep;
 703         char *                  cp;
 704         int                     load_result;
 705
 706         INITIALIZE(dstname);
 707         stdname = name;
 708         if (lastditch) {
 709                 stdlen = strlen(name);  /* length of standard zone name */
 710                 name += stdlen;
 711                 if (stdlen >= sizeof sp->chars)
 712                         stdlen = (sizeof sp->chars) - 1;
 713                 stdoffset = 0;
 714         } else {
 715                 name = getzname(name);
 716                 stdlen = name - stdname;
 717                 if (stdlen < 3)
 718                         return -1;
 719                 if (*name == '\0')
 720                         return -1;      /* was "stdoffset = 0;" */
 721                 else {
 722                         name = getoffset(name, &stdoffset);
 723                         if (name == NULL)
 724                                 return -1;
 725                 }
 726         }
 727         load_result = tzload(TZDEFRULES, sp);
 728         if (load_result != 0)
 729                 sp->leapcnt = 0;                /* so, we're off a little */
 730         if (*name != '\0') {
 731                 dstname = name;
 732                 name = getzname(name);
 733                 dstlen = name - dstname;        /* length of DST zone name */
 734                 if (dstlen < 3)
 735                         return -1;
 736                 if (*name != '\0' && *name != ',' && *name != ';') {
 737                         name = getoffset(name, &dstoffset);
 738                         if (name == NULL)
 739                                 return -1;
 740                 } else  dstoffset = stdoffset - SECSPERHOUR;
 741                 if (*name == ',' || *name == ';') {
 742                         struct rule     start;
 743                         struct rule     end;
 744                         int     year;
 745                         time_t  janfirst;
 746                         time_t          starttime;
 747                         time_t          endtime;
 748
 749                         ++name;
 750                         if ((name = getrule(name, &start)) == NULL)
 751                                 return -1;
 752                         if (*name++ != ',')
 753                                 return -1;
 754                         if ((name = getrule(name, &end)) == NULL)
 755                                 return -1;
 756                         if (*name != '\0')
 757                                 return -1;
 758                         sp->typecnt = 2;        /* standard time and DST */
 759                         /*
 760                         ** Two transitions per year, from EPOCH_YEAR to 2037.
 761                         */
 762                         sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
 763                         if (sp->timecnt > TZ_MAX_TIMES)
 764                                 return -1;
 765                         sp->ttis[0].tt_gmtoff = -dstoffset;
 766                         sp->ttis[0].tt_isdst = 1;
 767                         sp->ttis[0].tt_abbrind = stdlen + 1;
 768                         sp->ttis[1].tt_gmtoff = -stdoffset;
 769                         sp->ttis[1].tt_isdst = 0;
 770                         sp->ttis[1].tt_abbrind = 0;
 771                         atp = sp->ats;
 772                         typep = sp->types;
 773                         janfirst = 0;
 774                         for (year = EPOCH_YEAR; year <= 2037; ++year) {
 775                                 starttime = transtime(janfirst, year, &start,
 776                                         stdoffset);
 777                                 endtime = transtime(janfirst, year, &end,
 778                                         dstoffset);
 779                                 if (starttime > endtime) {
 780                                         *atp++ = endtime;
 781                                         *typep++ = 1;   /* DST ends */
 782                                         *atp++ = starttime;
 783                                         *typep++ = 0;   /* DST begins */
 784                                 } else {
 785                                         *atp++ = starttime;
 786                                         *typep++ = 0;   /* DST begins */
 787                                         *atp++ = endtime;
 788                                         *typep++ = 1;   /* DST ends */
 789                                 }
 790                                 janfirst += year_lengths[isleap(year)] *
 791                                         SECSPERDAY;
 792                         }
 793                 } else {
 794                         long    theirstdoffset;
 795                         long    theirdstoffset;
 796                         long    theiroffset;
 797                         int     isdst;
 798                         int     i;
 799                         int     j;
 800
 801                         if (*name != '\0')
 802                                 return -1;
 803                         if (load_result != 0)
 804                                 return -1;
 805                         /*
 806                         ** Initial values of theirstdoffset and theirdstoffset.
 807                         */
 808                         theirstdoffset = 0;
 809                         for (i = 0; i < sp->timecnt; ++i) {
 810                                 j = sp->types[i];
 811                                 if (!sp->ttis[j].tt_isdst) {
 812                                         theirstdoffset =
 813                                                 -sp->ttis[j].tt_gmtoff;
 814                                         break;
 815                                 }
 816                         }
 817                         theirdstoffset = 0;
 818                         for (i = 0; i < sp->timecnt; ++i) {
 819                                 j = sp->types[i];
 820                                 if (sp->ttis[j].tt_isdst) {
 821                                         theirdstoffset =
 822                                                 -sp->ttis[j].tt_gmtoff;
 823                                         break;
 824                                 }
 825                         }
 826                         /*
 827                         ** Initially we're assumed to be in standard time.
 828                         */
 829                         isdst = FALSE;
 830                         theiroffset = theirstdoffset;
 831                         /*
 832                         ** Now juggle transition times and types
 833                         ** tracking offsets as you do.
 834                         */
 835                         for (i = 0; i < sp->timecnt; ++i) {
 836                                 j = sp->types[i];
 837                                 sp->types[i] = sp->ttis[j].tt_isdst;
 838                                 if (sp->ttis[j].tt_ttisgmt) {
 839                                         /* No adjustment to transition time */
 840                                 } else {
 841                                         /*
 842                                         ** If summer time is in effect, and the
 843                                         ** transition time was not specified as
 844                                         ** standard time, add the summer time
 845                                         ** offset to the transition time;
 846                                         ** otherwise, add the standard time
 847                                         ** offset to the transition time.
 848                                         */
 849                                         /*
 850                                         ** Transitions from DST to DDST
 851                                         ** will effectively disappear since
 852                                         ** POSIX provides for only one DST
 853                                         ** offset.
 854                                         */
 855                                         if (isdst && !sp->ttis[j].tt_ttisstd) {
 856                                                 sp->ats[i] += dstoffset -
 857                                                         theirdstoffset;
 858                                         } else {
 859                                                 sp->ats[i] += stdoffset -
 860                                                         theirstdoffset;
 861                                         }
 862                                 }
 863                                 theiroffset = -sp->ttis[j].tt_gmtoff;
 864                                 if (sp->ttis[j].tt_isdst)
 865                                         theirdstoffset = theiroffset;
 866                                 else    theirstdoffset = theiroffset;
 867                         }
 868                         /*
 869                         ** Finally, fill in ttis.
 870                         ** ttisstd and ttisgmt need not be handled.
 871                         */
 872                         sp->ttis[0].tt_gmtoff = -stdoffset;
 873                         sp->ttis[0].tt_isdst = FALSE;
 874                         sp->ttis[0].tt_abbrind = 0;
 875                         sp->ttis[1].tt_gmtoff = -dstoffset;
 876                         sp->ttis[1].tt_isdst = TRUE;
 877                         sp->ttis[1].tt_abbrind = stdlen + 1;
 878                 }
 879         } else {
 880                 dstlen = 0;
 881                 sp->typecnt = 1;                /* only standard time */
 882                 sp->timecnt = 0;
 883                 sp->ttis[0].tt_gmtoff = -stdoffset;
 884                 sp->ttis[0].tt_isdst = 0;
 885                 sp->ttis[0].tt_abbrind = 0;
 886         }
 887         sp->charcnt = stdlen + 1;
 888         if (dstlen != 0)
 889                 sp->charcnt += dstlen + 1;
 890         if (sp->charcnt > sizeof sp->chars)
 891                 return -1;
 892         cp = sp->chars;
 893         strncpy(cp, stdname, stdlen);
 894         cp += stdlen;
 895         *cp++ = '\0';
 896         if (dstlen != 0) {
 897                 strncpy(cp, dstname, dstlen);
 898                 *(cp + dstlen) = '\0';
 899         }
 900         return 0;
 901 }
 902
 903 static void
 904 gmtload(struct state * const sp)
 905 {
 906         if (tzload(gmt, sp) != 0)
 907                 tzparse(gmt, sp, TRUE);
 908 }
 909
 910 static void
 911 tzsetwall_basic(void)
 912 {
 913         if (lcl_is_set < 0)
 914                 return;
 915         lcl_is_set = -1;
 916
 917 #ifdef ALL_STATE
 918         if (lclptr == NULL) {
 919                 lclptr = (struct state *) malloc(sizeof *lclptr);
 920                 if (lclptr == NULL) {
 921                         settzname();    /* all we can do */
 922                         return;
 923                 }
 924         }
 925 #endif /* defined ALL_STATE */
 926         if (tzload((char *) NULL, lclptr) != 0)
 927                 gmtload(lclptr);
 928         settzname();
 929 }
 930
 931 void
 932 tzsetwall(void)
 933 {
 934         _MUTEX_LOCK(&lcl_mutex);
 935         tzsetwall_basic();
 936         _MUTEX_UNLOCK(&lcl_mutex);
 937 }
 938
 939 static void
 940 tzset_basic(void)
 941 {
 942         const char *    name;
 943
 944         name = getenv("TZ");
 945         if (name == NULL) {
 946                 tzsetwall();
 947                 return;
 948         }
 949
 950         if (lcl_is_set > 0  &&  strcmp(lcl_TZname, name) == 0)
 951                 return;
 952         lcl_is_set = (strlen(name) < sizeof(lcl_TZname));
 953         if (lcl_is_set)
 954                 strcpy(lcl_TZname, name);
 955
 956 #ifdef ALL_STATE
 957         if (lclptr == NULL) {
 958                 lclptr = (struct state *) malloc(sizeof *lclptr);
 959                 if (lclptr == NULL) {
 960                         settzname();    /* all we can do */
 961                         return;
 962                 }
 963         }
 964 #endif /* defined ALL_STATE */
 965         if (*name == '\0') {
 966                 /*
 967                 ** User wants it fast rather than right.
 968                 */
 969                 lclptr->leapcnt = 0;            /* so, we're off a little */
 970                 lclptr->timecnt = 0;
 971                 lclptr->ttis[0].tt_gmtoff = 0;
 972                 lclptr->ttis[0].tt_abbrind = 0;
 973                 strcpy(lclptr->chars, gmt);
 974         } else if (tzload(name, lclptr) != 0)
 975                 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
 976                         gmtload(lclptr);
 977         settzname();
 978 }
 979
 980 void
 981 tzset(void)
 982 {
 983         _MUTEX_LOCK(&lcl_mutex);
 984         tzset_basic();
 985         _MUTEX_UNLOCK(&lcl_mutex);
 986 }
 987
 988 /*
 989 ** The easy way to behave "as if no library function calls" localtime
 990 ** is to not call it--so we drop its guts into "localsub", which can be
 991 ** freely called.  (And no, the PANS doesn't require the above behavior--
 992 ** but it *is* desirable.)
 993 **
 994 ** The unused offset argument is for the benefit of mktime variants.
 995 */
 996
 997 /*ARGSUSED*/
 998 static void
 999 localsub(const time_t * const timep, const long offset __unused,
1000          struct tm * const tmp)
1001 {
1002         struct state *          sp;
1003         const struct ttinfo *   ttisp;
1004         int                     i;
1005         const time_t                    t = *timep;
1006
1007         sp = lclptr;
1008 #ifdef ALL_STATE
1009         if (sp == NULL) {
1010                 gmtsub(timep, offset, tmp);
1011                 return;
1012         }
1013 #endif /* defined ALL_STATE */
1014         if (sp->timecnt == 0 || t < sp->ats[0]) {
1015                 i = 0;
1016                 while (sp->ttis[i].tt_isdst)
1017                         if (++i >= sp->typecnt) {
1018                                 i = 0;
1019                                 break;
1020                         }
1021         } else {
1022                 for (i = 1; i < sp->timecnt; ++i)
1023                         if (t < sp->ats[i])
1024                                 break;
1025                 i = sp->types[i - 1];
1026         }
1027         ttisp = &sp->ttis[i];
1028         /*
1029         ** To get (wrong) behavior that's compatible with System V Release 2.0
1030         ** you'd replace the statement below with
1031         **      t += ttisp->tt_gmtoff;
1032         **      timesub(&t, 0L, sp, tmp);
1033         */
1034         timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1035         tmp->tm_isdst = ttisp->tt_isdst;
1036         tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1037 #ifdef TM_ZONE
1038         tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1039 #endif /* defined TM_ZONE */
1040 }
1041
1042 struct tm *
1043 localtime_r(const time_t * const timep, struct tm *p_tm)
1044 {
1045         _MUTEX_LOCK(&lcl_mutex);
1046         tzset();
1047         localsub(timep, 0L, p_tm);
1048         _MUTEX_UNLOCK(&lcl_mutex);
1049         return(p_tm);
1050 }
1051
1052 struct tm *
1053 localtime(const time_t * const timep)
1054 {
1055         static pthread_mutex_t localtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1056         static pthread_key_t localtime_key = -1;
1057         struct tm *p_tm;
1058
1059         if (__isthreaded != 0) {
1060                 _pthread_mutex_lock(&localtime_mutex);
1061                 if (localtime_key < 0) {
1062                         if (_pthread_key_create(&localtime_key, free) < 0) {
1063                                 _pthread_mutex_unlock(&localtime_mutex);
1064                                 return(NULL);
1065                         }
1066                 }
1067                 _pthread_mutex_unlock(&localtime_mutex);
1068                 p_tm = _pthread_getspecific(localtime_key);
1069                 if (p_tm == NULL) {
1070                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1071                             == NULL)
1072                                 return(NULL);
1073                         _pthread_setspecific(localtime_key, p_tm);
1074                 }
1075                 _pthread_mutex_lock(&lcl_mutex);
1076                 tzset();
1077                 localsub(timep, 0L, p_tm);
1078                 _pthread_mutex_unlock(&lcl_mutex);
1079                 return(p_tm);
1080         } else {
1081                 tzset();
1082                 localsub(timep, 0L, &tm);
1083                 return(&tm);
1084         }
1085 }
1086
1087 /*
1088 ** gmtsub is to gmtime as localsub is to localtime.
1089 */
1090
1091 static void
1092 gmtsub(const time_t * const timep, const long offset, struct tm * const tmp)
1093 {
1094         _MUTEX_LOCK(&gmt_mutex);
1095         if (!gmt_is_set) {
1096                 gmt_is_set = TRUE;
1097 #ifdef ALL_STATE
1098                 gmtptr = (struct state *) malloc(sizeof *gmtptr);
1099                 if (gmtptr != NULL)
1100 #endif /* defined ALL_STATE */
1101                         gmtload(gmtptr);
1102         }
1103         _MUTEX_UNLOCK(&gmt_mutex);
1104         timesub(timep, offset, gmtptr, tmp);
1105 #ifdef TM_ZONE
1106         /*
1107         ** Could get fancy here and deliver something such as
1108         ** "GMT+xxxx" or "GMT-xxxx" if offset is non-zero,
1109         ** but this is no time for a treasure hunt.
1110         */
1111         if (offset != 0)
1112                 tmp->TM_ZONE = wildabbr;
1113         else {
1114 #ifdef ALL_STATE
1115                 if (gmtptr == NULL)
1116                         tmp->TM_ZONE = gmt;
1117                 else    tmp->TM_ZONE = gmtptr->chars;
1118 #endif /* defined ALL_STATE */
1119 #ifndef ALL_STATE
1120                 tmp->TM_ZONE = gmtptr->chars;
1121 #endif /* State Farm */
1122         }
1123 #endif /* defined TM_ZONE */
1124 }
1125
1126 struct tm *
1127 gmtime(const time_t * const timep)
1128 {
1129         static pthread_mutex_t gmtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1130         static pthread_key_t gmtime_key = -1;
1131         struct tm *p_tm;
1132
1133         if (__isthreaded != 0) {
1134                 _pthread_mutex_lock(&gmtime_mutex);
1135                 if (gmtime_key < 0) {
1136                         if (_pthread_key_create(&gmtime_key, free) < 0) {
1137                                 _pthread_mutex_unlock(&gmtime_mutex);
1138                                 return(NULL);
1139                 }
1140         }
1141         _pthread_mutex_unlock(&gmtime_mutex);
1142                 /*
1143                  * Changed to follow POSIX.1 threads standard, which
1144                  * is what BSD currently has.
1145                  */
1146                 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1147                         if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1148                             == NULL) {
1149                                 return(NULL);
1150                         }
1151                         _pthread_setspecific(gmtime_key, p_tm);
1152                 }
1153                 gmtsub(timep, 0L, p_tm);
1154                 return(p_tm);
1155         }
1156         else {
1157                 gmtsub(timep, 0L, &tm);
1158                 return(&tm);
1159         }
1160 }
1161
1162 struct tm *
1163 gmtime_r(const time_t * timep, struct tm * tm_p)
1164 {
1165         gmtsub(timep, 0L, tm_p);
1166         return(tm_p);
1167 }
1168
1169 #ifdef STD_INSPIRED
1170
1171 struct tm *
1172 offtime(const time_t * const timep, const long offset)
1173 {
1174         gmtsub(timep, offset, &tm);
1175         return &tm;
1176 }
1177
1178 #endif /* defined STD_INSPIRED */
1179
1180 static void
1181 timesub(const time_t * const timep, const long offset,
1182         const struct state * const sp, struct tm * const tmp)
1183 {
1184         const struct lsinfo *   lp;
1185         long                    days;
1186         long                    rem;
1187         int                     y;
1188         int                     yleap;
1189         const int *             ip;
1190         long                    corr;
1191         int                     hit;
1192         int                     i;
1193
1194         corr = 0;
1195         hit = 0;
1196 #ifdef ALL_STATE
1197         i = (sp == NULL) ? 0 : sp->leapcnt;
1198 #endif /* defined ALL_STATE */
1199 #ifndef ALL_STATE
1200         i = sp->leapcnt;
1201 #endif /* State Farm */
1202         while (--i >= 0) {
1203                 lp = &sp->lsis[i];
1204                 if (*timep >= lp->ls_trans) {
1205                         if (*timep == lp->ls_trans) {
1206                                 hit = ((i == 0 && lp->ls_corr > 0) ||
1207                                         lp->ls_corr > sp->lsis[i - 1].ls_corr);
1208                                 if (hit)
1209                                         while (i > 0 &&
1210                                                 sp->lsis[i].ls_trans ==
1211                                                 sp->lsis[i - 1].ls_trans + 1 &&
1212                                                 sp->lsis[i].ls_corr ==
1213                                                 sp->lsis[i - 1].ls_corr + 1) {
1214                                                         ++hit;
1215                                                         --i;
1216                                         }
1217                         }
1218                         corr = lp->ls_corr;
1219                         break;
1220                 }
1221         }
1222         days = *timep / SECSPERDAY;
1223         rem = *timep % SECSPERDAY;
1224 #ifdef mc68k
1225         if (*timep == 0x80000000) {
1226                 /*
1227                 ** A 3B1 muffs the division on the most negative number.
1228                 */
1229                 days = -24855;
1230                 rem = -11648;
1231         }
1232 #endif /* defined mc68k */
1233         rem += (offset - corr);
1234         while (rem < 0) {
1235                 rem += SECSPERDAY;
1236                 --days;
1237         }
1238         while (rem >= SECSPERDAY) {
1239                 rem -= SECSPERDAY;
1240                 ++days;
1241         }
1242         tmp->tm_hour = (int) (rem / SECSPERHOUR);
1243         rem = rem % SECSPERHOUR;
1244         tmp->tm_min = (int) (rem / SECSPERMIN);
1245         /*
1246         ** A positive leap second requires a special
1247         ** representation.  This uses "... ??:59:60" et seq.
1248         */
1249         tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1250         tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
1251         if (tmp->tm_wday < 0)
1252                 tmp->tm_wday += DAYSPERWEEK;
1253         y = EPOCH_YEAR;
1254 #define LEAPS_THRU_END_OF(y)    ((y) / 4 - (y) / 100 + (y) / 400)
1255         while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
1256                 int     newy;
1257
1258                 newy = y + days / DAYSPERNYEAR;
1259                 if (days < 0)
1260                         --newy;
1261                 days -= (newy - y) * DAYSPERNYEAR +
1262                         LEAPS_THRU_END_OF(newy - 1) -
1263                         LEAPS_THRU_END_OF(y - 1);
1264                 y = newy;
1265         }
1266         tmp->tm_year = y - TM_YEAR_BASE;
1267         tmp->tm_yday = (int) days;
1268         ip = mon_lengths[yleap];
1269         for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
1270                 days = days - (long) ip[tmp->tm_mon];
1271         tmp->tm_mday = (int) (days + 1);
1272         tmp->tm_isdst = 0;
1273 #ifdef TM_GMTOFF
1274         tmp->TM_GMTOFF = offset;
1275 #endif /* defined TM_GMTOFF */
1276 }
1277
1278 char *
1279 ctime(const time_t * const timep)
1280 {
1281 /*
1282 ** Section 4.12.3.2 of X3.159-1989 requires that
1283 **      The ctime funciton converts the calendar time pointed to by timer
1284 **      to local time in the form of a string.  It is equivalent to
1285 **              asctime(localtime(timer))
1286 */
1287         return asctime(localtime(timep));
1288 }
1289
1290 char *
1291 ctime_r(const time_t * const timep, char *buf)
1292 {
1293         struct tm tm1;
1294         return asctime_r(localtime_r(timep, &tm1), buf);
1295 }
1296
1297 /*
1298 ** Adapted from code provided by Robert Elz, who writes:
1299 **      The "best" way to do mktime I think is based on an idea of Bob
1300 **      Kridle's (so its said...) from a long time ago.
1301 **      [kridle@xinet.com as of 1996-01-16.]
1302 **      It does a binary search of the time_t space.  Since time_t's are
1303 **      just 32 bits, its a max of 32 iterations (even at 64 bits it
1304 **      would still be very reasonable).
1305 */
1306
1307 #ifndef WRONG
1308 #define WRONG   (-1)
1309 #endif /* !defined WRONG */
1310
1311 /*
1312 ** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
1313 */
1314
1315 static int
1316 increment_overflow(int *number, int delta)
1317 {
1318         int     number0;
1319
1320         number0 = *number;
1321         *number += delta;
1322         return (*number < number0) != (delta < 0);
1323 }
1324
1325 static int
1326 normalize_overflow(int * const tensptr, int * const unitsptr, const int base)
1327 {
1328         int     tensdelta;
1329
1330         tensdelta = (*unitsptr >= 0) ?
1331                 (*unitsptr / base) :
1332                 (-1 - (-1 - *unitsptr) / base);
1333         *unitsptr -= tensdelta * base;
1334         return increment_overflow(tensptr, tensdelta);
1335 }
1336
1337 static int
1338 tmcomp(const struct tm * const atmp, const struct tm * const btmp)
1339 {
1340         int     result;
1341
1342         if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1343                 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1344                 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1345                 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1346                 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1347                         result = atmp->tm_sec - btmp->tm_sec;
1348         return result;
1349 }
1350
1351 static time_t
1352 time2(struct tm * const tmp,
1353       void (* const funcp)(const time_t *, long, struct tm *),
1354       const long offset, int * const okayp)
1355 {
1356         const struct state *    sp;
1357         int                     dir;
1358         int                     bits;
1359         int                     i, j ;
1360         int                     saved_seconds;
1361         time_t                          newt;
1362         time_t                          t;
1363         struct tm                       yourtm, mytm;
1364
1365         *okayp = FALSE;
1366         yourtm = *tmp;
1367         if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1368                 return WRONG;
1369         if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1370                 return WRONG;
1371         if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
1372                 return WRONG;
1373         /*
1374         ** Turn yourtm.tm_year into an actual year number for now.
1375         ** It is converted back to an offset from TM_YEAR_BASE later.
1376         */
1377         if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
1378                 return WRONG;
1379         while (yourtm.tm_mday <= 0) {
1380                 if (increment_overflow(&yourtm.tm_year, -1))
1381                         return WRONG;
1382                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1383                 yourtm.tm_mday += year_lengths[isleap(i)];
1384         }
1385         while (yourtm.tm_mday > DAYSPERLYEAR) {
1386                 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1387                 yourtm.tm_mday -= year_lengths[isleap(i)];
1388                 if (increment_overflow(&yourtm.tm_year, 1))
1389                         return WRONG;
1390         }
1391         for ( ; ; ) {
1392                 i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
1393                 if (yourtm.tm_mday <= i)
1394                         break;
1395                 yourtm.tm_mday -= i;
1396                 if (++yourtm.tm_mon >= MONSPERYEAR) {
1397                         yourtm.tm_mon = 0;
1398                         if (increment_overflow(&yourtm.tm_year, 1))
1399                                 return WRONG;
1400                 }
1401         }
1402         if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
1403                 return WRONG;
1404         if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
1405                 /*
1406                 ** We can't set tm_sec to 0, because that might push the
1407                 ** time below the minimum representable time.
1408                 ** Set tm_sec to 59 instead.
1409                 ** This assumes that the minimum representable time is
1410                 ** not in the same minute that a leap second was deleted from,
1411                 ** which is a safer assumption than using 58 would be.
1412                 */
1413                 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1414                         return WRONG;
1415                 saved_seconds = yourtm.tm_sec;
1416                 yourtm.tm_sec = SECSPERMIN - 1;
1417         } else {
1418                 saved_seconds = yourtm.tm_sec;
1419                 yourtm.tm_sec = 0;
1420         }
1421         /*
1422         ** Divide the search space in half
1423         ** (this works whether time_t is signed or unsigned).
1424         */
1425         bits = TYPE_BIT(time_t) - 1;
1426         /*
1427         ** If time_t is signed, then 0 is just above the median,
1428         ** assuming two's complement arithmetic.
1429         ** If time_t is unsigned, then (1 << bits) is just above the median.
1430         */
1431         t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
1432         for ( ; ; ) {
1433                 (*funcp)(&t, offset, &mytm);
1434                 dir = tmcomp(&mytm, &yourtm);
1435                 if (dir != 0) {
1436                         if (bits-- < 0)
1437                                 return WRONG;
1438                         if (bits < 0)
1439                                 --t; /* may be needed if new t is minimal */
1440                         else if (dir > 0)
1441                                 t -= ((time_t) 1) << bits;
1442                         else    t += ((time_t) 1) << bits;
1443                         continue;
1444                 }
1445                 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1446                         break;
1447                 /*
1448                 ** Right time, wrong type.
1449                 ** Hunt for right time, right type.
1450                 ** It's okay to guess wrong since the guess
1451                 ** gets checked.
1452                 */
1453                 /*
1454                 ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1455                 */
1456                 sp = (const struct state *)
1457                         (((void *) funcp == (void *) localsub) ?
1458                         lclptr : gmtptr);
1459 #ifdef ALL_STATE
1460                 if (sp == NULL)
1461                         return WRONG;
1462 #endif /* defined ALL_STATE */
1463                 for (i = sp->typecnt - 1; i >= 0; --i) {
1464                         if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1465                                 continue;
1466                         for (j = sp->typecnt - 1; j >= 0; --j) {
1467                                 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1468                                         continue;
1469                                 newt = t + sp->ttis[j].tt_gmtoff -
1470                                         sp->ttis[i].tt_gmtoff;
1471                                 (*funcp)(&newt, offset, &mytm);
1472                                 if (tmcomp(&mytm, &yourtm) != 0)
1473                                         continue;
1474                                 if (mytm.tm_isdst != yourtm.tm_isdst)
1475                                         continue;
1476                                 /*
1477                                 ** We have a match.
1478                                 */
1479                                 t = newt;
1480                                 goto label;
1481                         }
1482                 }
1483                 return WRONG;
1484         }
1485 label:
1486         newt = t + saved_seconds;
1487         if ((newt < t) != (saved_seconds < 0))
1488                 return WRONG;
1489         t = newt;
1490         (*funcp)(&t, offset, tmp);
1491         *okayp = TRUE;
1492         return t;
1493 }
1494
1495 static time_t
1496 time1(struct tm * const tmp,
1497       void (* const funcp)(const time_t *, long, struct tm *),
1498       const long offset)
1499 {
1500         time_t                  t;
1501         const struct state *    sp;
1502         int                     samei, otheri;
1503         int                             okay;
1504
1505         if (tmp->tm_isdst > 1)
1506                 tmp->tm_isdst = 1;
1507         t = time2(tmp, funcp, offset, &okay);
1508 #ifdef PCTS
1509         /*
1510         ** PCTS code courtesy Grant Sullivan (grant@osf.org).
1511         */
1512         if (okay)
1513                 return t;
1514         if (tmp->tm_isdst < 0)
1515                 tmp->tm_isdst = 0;      /* reset to std and try again */
1516 #endif /* defined PCTS */
1517 #ifndef PCTS
1518         if (okay || tmp->tm_isdst < 0)
1519                 return t;
1520 #endif /* !defined PCTS */
1521         /*
1522         ** We're supposed to assume that somebody took a time of one type
1523         ** and did some math on it that yielded a "struct tm" that's bad.
1524         ** We try to divine the type they started from and adjust to the
1525         ** type they need.
1526         */
1527         /*
1528         ** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1529         */
1530         sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
1531                 lclptr : gmtptr);
1532 #ifdef ALL_STATE
1533         if (sp == NULL)
1534                 return WRONG;
1535 #endif /* defined ALL_STATE */
1536         for (samei = sp->typecnt - 1; samei >= 0; --samei) {
1537                 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1538                         continue;
1539                 for (otheri = sp->typecnt - 1; otheri >= 0; --otheri) {
1540                         if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1541                                 continue;
1542                         tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1543                                         sp->ttis[samei].tt_gmtoff;
1544                         tmp->tm_isdst = !tmp->tm_isdst;
1545                         t = time2(tmp, funcp, offset, &okay);
1546                         if (okay)
1547                                 return t;
1548                         tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1549                                         sp->ttis[samei].tt_gmtoff;
1550                         tmp->tm_isdst = !tmp->tm_isdst;
1551                 }
1552         }
1553         return WRONG;
1554 }
1555
1556 time_t
1557 mktime(struct tm * const tmp)
1558 {
1559         time_t mktime_return_value;
1560         _MUTEX_LOCK(&lcl_mutex);
1561         tzset();
1562         mktime_return_value = time1(tmp, localsub, 0L);
1563         _MUTEX_UNLOCK(&lcl_mutex);
1564         return(mktime_return_value);
1565 }
1566
1567 #ifdef STD_INSPIRED
1568
1569 time_t
1570 timelocal(struct tm * const tmp)
1571 {
1572         tmp->tm_isdst = -1;     /* in case it wasn't initialized */
1573         return mktime(tmp);
1574 }
1575
1576 time_t
1577 timegm(struct tm * const tmp)
1578 {
1579         tmp->tm_isdst = 0;
1580         return time1(tmp, gmtsub, 0L);
1581 }
1582
1583 time_t
1584 timeoff(struct tm * const tmp, const long offset)
1585 {
1586         tmp->tm_isdst = 0;
1587         return time1(tmp, gmtsub, offset);
1588 }
1589
1590 #endif /* defined STD_INSPIRED */
1591
1592 #ifdef CMUCS
1593
1594 /*
1595 ** The following is supplied for compatibility with
1596 ** previous versions of the CMUCS runtime library.
1597 */
1598
1599 long
1600 gtime(struct tm * const tmp)
1601 {
1602         const time_t    t = mktime(tmp);
1603
1604         if (t == WRONG)
1605                 return -1;
1606         return t;
1607 }
1608
1609 #endif /* defined CMUCS */
1610
1611 /*
1612 ** XXX--is the below the right way to conditionalize??
1613 */
1614
1615 #ifdef STD_INSPIRED
1616
1617 /*
1618 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1619 ** shall correspond to "Wed Dec 31 23:59:59 GMT 1986", which
1620 ** is not the case if we are accounting for leap seconds.
1621 ** So, we provide the following conversion routines for use
1622 ** when exchanging timestamps with POSIX conforming systems.
1623 */
1624
1625 static long
1626 leapcorr(time_t *timep)
1627 {
1628         struct state *          sp;
1629         struct lsinfo * lp;
1630         int                     i;
1631
1632         sp = lclptr;
1633         i = sp->leapcnt;
1634         while (--i >= 0) {
1635                 lp = &sp->lsis[i];
1636                 if (*timep >= lp->ls_trans)
1637                         return lp->ls_corr;
1638         }
1639         return 0;
1640 }
1641
1642 time_t
1643 time2posix(time_t t)
1644 {
1645         tzset();
1646         return t - leapcorr(&t);
1647 }
1648
1649 time_t
1650 posix2time(time_t t)
1651 {
1652         time_t  x;
1653         time_t  y;
1654
1655         tzset();
1656         /*
1657         ** For a positive leap second hit, the result
1658         ** is not unique.  For a negative leap second
1659         ** hit, the corresponding time doesn't exist,
1660         ** so we return an adjacent second.
1661         */
1662         x = t + leapcorr(&t);
1663         y = x - leapcorr(&x);
1664         if (y < t) {
1665                 do {
1666                         x++;
1667                         y = x - leapcorr(&x);
1668                 } while (y < t);
1669                 if (t != y)
1670                         return x - 1;
1671         } else if (y > t) {
1672                 do {
1673                         --x;
1674                         y = x - leapcorr(&x);
1675                 } while (y > t);
1676                 if (t != y)
1677                         return x + 1;
1678         }
1679         return x;
1680 }
1681
1682 #endif /* defined STD_INSPIRED */