1 files changed, 17 insertions, 74 deletions

diff --git a/localtime.c b/localtime.c
index 940a04fd09ab..7ae9ce5e519d 100644
--- a/localtime.c
+++ b/localtime.c
@@ -106,7 +106,7 @@ static char const UNSPEC[] = "-00";
    for ttunspecified to work without crashing.  */
 enum { CHARS_EXTRA = max(sizeof UNSPEC, 2) - 1 };
 
-/* Limit to time zone abbreviation length in POSIX.1-2017-style TZ strings.
+/* Limit to time zone abbreviation length in proleptic TZ strings.
    This is distinct from TZ_MAX_CHARS, which limits TZif file contents.  */
 #ifndef TZNAME_MAXIMUM
 # define TZNAME_MAXIMUM 255
@@ -130,11 +130,6 @@ struct state {
 	char chars[max(max(TZ_MAX_CHARS + CHARS_EXTRA, sizeof "UTC"),
 		       2 * (TZNAME_MAXIMUM + 1))];
 	struct lsinfo	lsis[TZ_MAX_LEAPS];
-
-	/* The time type to use for early times or if no transitions.
-	   It is always zero for recent tzdb releases.
-	   It might be nonzero for data from tzdb 2018e or earlier.  */
-	int defaulttype;
 };
 
 enum r_type {
@@ -187,8 +182,9 @@ static int		lcl_is_set;
 **	objects: a broken-down time structure and an array of char.
 ** Thanks to Paul Eggert for noting this.
 **
-** This requirement was removed in C99, so support it only if requested,
-** as support is more likely to lead to bugs in badly written programs.
+** Although this requirement was removed in C99 it is still present in POSIX.
+** Follow the requirement if SUPPORT_C89, even though this is more likely to
+** trigger latent bugs in programs.
 */
 
 #if SUPPORT_C89
@@ -710,58 +706,6 @@ tzloadbody(char const *name, struct state *sp, bool doextend,
 	if (sp->typecnt == 0)
 	  return EINVAL;
 
-	/* Infer sp->defaulttype from the data.  Although this default
-	   type is always zero for data from recent tzdb releases,
-	   things are trickier for data from tzdb 2018e or earlier.
-
-	   The first set of heuristics work around bugs in 32-bit data
-	   generated by tzdb 2013c or earlier.  The workaround is for
-	   zones like Australia/Macquarie where timestamps before the
-	   first transition have a time type that is not the earliest
-	   standard-time type.  See:
-	   https://mm.icann.org/pipermail/tz/2013-May/019368.html */
-	/*
-	** If type 0 does not specify local time, or is unused in transitions,
-	** it's the type to use for early times.
-	*/
-	for (i = 0; i < sp->timecnt; ++i)
-		if (sp->types[i] == 0)
-			break;
-	i = i < sp->timecnt && ! ttunspecified(sp, 0) ? -1 : 0;
-	/*
-	** Absent the above,
-	** if there are transition times
-	** and the first transition is to a daylight time
-	** find the standard type less than and closest to
-	** the type of the first transition.
-	*/
-	if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
-		i = sp->types[0];
-		while (--i >= 0)
-			if (!sp->ttis[i].tt_isdst)
-				break;
-	}
-	/* The next heuristics are for data generated by tzdb 2018e or
-	   earlier, for zones like EST5EDT where the first transition
-	   is to DST.  */
-	/*
-	** If no result yet, find the first standard type.
-	** If there is none, punt to type zero.
-	*/
-	if (i < 0) {
-		i = 0;
-		while (sp->ttis[i].tt_isdst)
-			if (++i >= sp->typecnt) {
-				i = 0;
-				break;
-			}
-	}
-	/* A simple 'sp->defaulttype = 0;' would suffice here if we
-	   didn't have to worry about 2018e-or-earlier data.  Even
-	   simpler would be to remove the defaulttype member and just
-	   use 0 in its place.  */
-	sp->defaulttype = i;
-
 	return 0;
 }
 
@@ -807,7 +751,7 @@ is_digit(char c)
 ** Return a pointer to that character.
 */
 
-ATTRIBUTE_REPRODUCIBLE static const char *
+ATTRIBUTE_PURE_114833 static const char *
 getzname(register const char *strp)
 {
 	register char	c;
@@ -828,7 +772,7 @@ getzname(register const char *strp)
 ** We don't do any checking here; checking is done later in common-case code.
 */
 
-ATTRIBUTE_REPRODUCIBLE static const char *
+ATTRIBUTE_PURE_114833 static const char *
 getqzname(register const char *strp, const int delim)
 {
 	register int	c;
@@ -1080,7 +1024,7 @@ transtime(const int year, register const struct rule *const rulep,
 }
 
 /*
-** Given a POSIX.1-2017-style TZ string, fill in the rule tables as
+** Given a POSIX.1 proleptic TZ string, fill in the rule tables as
 ** appropriate.
 */
 
@@ -1183,11 +1127,13 @@ tzparse(const char *name, struct state *sp, struct state const *basep)
 			do {
 			  int_fast32_t yearsecs
 			    = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
+			  time_t janfirst1 = janfirst;
 			  yearbeg--;
-			  if (increment_overflow_time(&janfirst, -yearsecs)) {
+			  if (increment_overflow_time(&janfirst1, -yearsecs)) {
 			    janoffset = -yearsecs;
 			    break;
 			  }
+			  janfirst = janfirst1;
 			} while (atlo < janfirst
 				 && EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
 
@@ -1313,7 +1259,7 @@ tzparse(const char *name, struct state *sp, struct state const *basep)
 					/*
 					** Transitions from DST to DDST
 					** will effectively disappear since
-					** POSIX.1-2017 provides for only one
+					** proleptic TZ strings have only one
 					** DST offset.
 					*/
 					if (isdst && !sp->ttis[j].tt_ttisstd) {
@@ -1342,7 +1288,6 @@ tzparse(const char *name, struct state *sp, struct state const *basep)
 		sp->timecnt = 0;
 		init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
 	}
-	sp->defaulttype = 0;
 	sp->charcnt = charcnt;
 	cp = sp->chars;
 	memcpy(cp, stdname, stdlen);
@@ -1378,7 +1323,6 @@ zoneinit(struct state *sp, char const *name)
     sp->goback = sp->goahead = false;
     init_ttinfo(&sp->ttis[0], 0, false, 0);
     strcpy(sp->chars, utc);
-    sp->defaulttype = 0;
     return 0;
   } else {
     int err = tzload(name, sp, true);
@@ -1465,8 +1409,8 @@ tzfree(timezone_t sp)
 }
 
 /*
-** NetBSD 6.1.4 has ctime_rz, but omit it because POSIX says ctime and
-** ctime_r are obsolescent and have potential security problems that
+** NetBSD 6.1.4 has ctime_rz, but omit it because C23 deprecates ctime and
+** POSIX.1-2024 removes ctime_r.  Both have potential security problems that
 ** ctime_rz would share.  Callers can instead use localtime_rz + strftime.
 **
 ** NetBSD 6.1.4 has tzgetname, but omit it because it doesn't work
@@ -1484,8 +1428,7 @@ tzfree(timezone_t sp)
 **
 ** If successful and SETNAME is nonzero,
 ** set the applicable parts of tzname, timezone and altzone;
-** however, it's OK to omit this step
-** if the timezone is compatible with POSIX.1-2017
+** however, it's OK to omit this step for proleptic TZ strings
 ** since in that case tzset should have already done this step correctly.
 ** SETNAME's type is int_fast32_t for compatibility with gmtsub,
 ** but it is actually a boolean and its value should be 0 or 1.
@@ -1553,7 +1496,7 @@ localsub(struct state const *sp, time_t const *timep, int_fast32_t setname,
 			return result;
 	}
 	if (sp->timecnt == 0 || t < sp->ats[0]) {
-		i = sp->defaulttype;
+		i = 0;
 	} else {
 		register int	lo = 1;
 		register int	hi = sp->timecnt;
@@ -2285,7 +2228,7 @@ mktime(struct tm *tmp)
 }
 
 #if STD_INSPIRED
-/* This function is obsolescent and may disapper in future releases.
+/* This function is obsolescent and may disappear in future releases.
    Callers can instead use mktime.  */
 time_t
 timelocal(struct tm *tmp)
@@ -2303,7 +2246,7 @@ timelocal(struct tm *tmp)
 # define EXTERN_TIMEOFF static
 #endif
 
-/* This function is obsolescent and may disapper in future releases.
+/* This function is obsolescent and may disappear in future releases.
    Callers can instead use mktime_z with a fixed-offset zone.  */
 EXTERN_TIMEOFF time_t
 timeoff(struct tm *tmp, long offset)