Squashed 'tz/' changes from 6903dde39e..5ad5cfba5b

a8e2fcd87b Release 2025a 4ab8692704 Fix bugs in -Wcast-qual pacification 1ee9daa918 Pacify gcc -Wcast-qual e8920e76fc Rename emalloc to xmalloc. cda7ec0702 Alias asctime, ctime result edbabecc14 Fix ctime conformace bug 7db03d5b98 Add missing zdump.o dependency e8e1a3d25b NetBSD defines STD_INSPIRED functions d89a7468e3 newctime doc improvements da932ff7ec Stop using \*- in man pages b6adb83ce3 Warn about 2-digit years in strftime man page 562a1f1631 Modernize date man page 9ab3f52d34 No leap second on 2025-06-30 e5aaf1c7fe For timestamps compare to HEAD not to index aa8a059d13 State the duplicate guideline more clearly cb537f2001 Suggest -Dssize_t=int, not long 352dcdf9e3 Port S_ISREG to ancient UNIX, recent MS-Windows 3411494cc7 Define _CRT_DECLARE_NONSTDC_NAMES for MS-Windows 7d776e798c Port ‘utc’ to MS-Windows 7c90916644 Define NOMINMAX for MS-Windows 94931e3006 Fix asctime.o, strftime.o dependencies d23b9bf5fd Fix to2050.tzs timestamp in distributed tarball 24a4d97fc0 'zdump -' now reads from stdin 6d77c92872 Bring back zdump on a pipe f5d6c1d7d9 Invalid TZ now abbreviates as "-00" not "UTC" a7ad244f30 Check for TZ naming a device 43cc9b6149 Fix unlikely multithreaded file descriptor leak b208d5841e Etc/Unknown is now reserved 13bc796952 Update USDOT map description de6dab1b23 Fix checknow confusing diagnostics 5e95797d9a * tz-link.html: Mention DoT geodata (thanks to Roozbeh Pournader). 3862447e2d Optimize asctime snprintf calls 161563657b Port recent asctime snprintf changes to NetBSD e6d6bc3e45 Pacify gcc -Wsuggest-attribute=format sans snprintf in zdump 9955786265 TZNAME_MAXIMUM defaults to 254, not 255 fe5be99d8d Be more consistent about macro true/false vs 1/0 3d5e7acb88 Port asctime_r to POSIX.1-2017 and earlier 31f483a149 Remove dependency of asctime on strftime 7ef7ed06b2 Simplify timeoff redefinition 1bd67a4b75 Move MKTIME_MIGHT_OVERFLOW definition 67f7e8ab9c Pacify GCC 15ish -Wzero-as-null-pointer-constant 535a4e8b25 Pacify GCC 15ish -Wleading-whitespace=blanks 59ae22db9b Revert zone.tab changes for Concordia, EBO abb83041a2 Fix mktime/timeoff overflow bug 0706ef0bf8 Move iinntt definition fa004d323c Add two research stations to zone*.tab 38eea0e263 Reorder australia comments 77820eb701 Mention the Eyre Bird Observatory d9e7a42f11 Avoid time_t + int overflow ea814e998d strftime %s no longer is limited to time_t range b2ee68e092 Simplify AmigaOS support 41e5344e6f Fix bug near the year 2**31 - 1 - 1900 4e1de2496e Pacify gcc -Wsuggest-attribute=const ebd2ed9235 Don’t define _FILE_OFFSET_BITS if _TIME_BITS 26a649a19e Improve zdump overflow checking 81bab74a7f * northamerica: Also mention Sandford Fleming and Cleveland Abbe. cfacf5ea70 strftime now outputs unknown conversions as-is 9c8221d79c * private.h: Fix timeoff comment. 705dc023c2 Remove now-dead strftime code d8b6fe65c9 Fix Asia/Manila post-1990 typo 3a83f10003 * NEWS, europe: Belated thanks for Ittoqqortoormiit 2024 fix 17fbd40e5c * NEWS: Belated thanks for Palestine 2072-2075 fix 493df554af Prefer www.rfc-editor.org for RFCs 9db906a00f Switch from RFC 8536 to 9636 for documentation be62d59182 Talk a bit more about tm_isdst's obsolescence 258a3775c0 tzfile man page editorial changes af54a9e896 Port better to glibc when used internally there 486e1e890e Paraguay tm_isdst flag goes to 0 today 636e6f983b Paraguay adopts permanent -03 starting spring 2024 e6258faabc Concordia can use Asia/Singapore 19b35d7db2 More changes for global-tz convenience 07731a9f6a "j" could mean June, too 66183d1e25 Fix "many" typo in NEWS 96fa7b7dd4 Document month, weekday names better 7b6fb155ca Improve style checks for months 926b507fa5 "Apr", not "April", in IN column d4c65d53b9 Improve historical data for the Philippines git-subtree-dir: tz git-subtree-split: 5ad5cfba5b092fe6abdc6870438cc09bcffbdd4b
stub42 · Jan 31, 2025 · 7abdc14 · 7abdc14
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diff --git a/Makefile b/Makefile
@@ -137,7 +137,7 @@ TIME_T_ALTERNATIVES_TAIL = int_least32_t.ck uint_least32_t.ck \
   uint_least64_t.ck
 
 # What kind of TZif data files to generate.  (TZif is the binary time
-# zone data format that zic generates; see Internet RFC 8536.)
+# zone data format that zic generates; see Internet RFC 9636.)
 # If you want only POSIX time, with time values interpreted as
 # seconds since the epoch (not counting leap seconds), use
 #	REDO=		posix_only
@@ -255,14 +255,15 @@ LDLIBS=
 #  -DHAVE_UNISTD_H=0 if <unistd.h> does not work*
 #  -DHAVE_UTMPX_H=0 if <utmpx.h> does not work*
 #  -Dlocale_t=XXX if your system uses XXX instead of locale_t
+#  -DMKTIME_MIGHT_OVERFLOW if mktime might fail due to time_t overflow
 #  -DPORT_TO_C89 if tzcode should also run on mostly-C89 platforms+
 #	Typically it is better to use a later standard.  For example,
 #	with GCC 4.9.4 (2016), prefer '-std=gnu11' to '-DPORT_TO_C89'.
 #	Even with -DPORT_TO_C89, the code needs at least one C99
 #	feature (integers at least 64 bits wide) and maybe more.
 #  -DRESERVE_STD_EXT_IDS if your platform reserves standard identifiers
 #	with external linkage, e.g., applications cannot define 'localtime'.
-#  -Dssize_t=long on hosts like MS-Windows that lack ssize_t
+#  -Dssize_t=int on hosts like MS-Windows that lack ssize_t
 #  -DSUPPORT_C89=0 if the tzcode library should not support C89 callers
 #	Although -DSUPPORT_C89=0 might work around latent bugs in callers,
 #	it does not conform to POSIX.
@@ -285,7 +286,7 @@ LDLIBS=
 #	This mishandles some past timestamps, as US DST rules have changed.
 #	It also mishandles settings like TZ='EET-2EEST' for eastern Europe,
 #	as Europe and US DST rules differ.
-#  -DTZNAME_MAXIMUM=N to limit time zone abbreviations to N bytes (default 255)
+#  -DTZNAME_MAXIMUM=N to limit time zone abbreviations to N bytes (default 254)
 #  -DUNINIT_TRAP if reading uninitialized storage can cause problems
 #	other than simply getting garbage data
 #  -DUSE_LTZ=0 to build zdump with the system time zone library
@@ -319,7 +320,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \
   $(GCC_INSTRUMENT) \
   -Wall -Wextra \
   -Walloc-size-larger-than=100000 -Warray-bounds=2 \
-  -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wdate-time \
+  -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wcast-qual \
+  -Wdate-time \
   -Wdeclaration-after-statement -Wdouble-promotion \
   -Wduplicated-branches -Wduplicated-cond -Wflex-array-member-not-at-end \
   -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
@@ -336,7 +338,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \
   -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
   -Wtrampolines -Wundef -Wunused-macros -Wuse-after-free=3 \
   -Wvariadic-macros -Wvla -Wwrite-strings \
-  -Wno-format-nonliteral -Wno-sign-compare
+  -Wno-format-nonliteral -Wno-sign-compare -Wno-type-limits
 #
 # If your system has a "GMT offset" field in its "struct tm"s
 # (or if you decide to add such a field in your system's "time.h" file),
@@ -614,8 +616,8 @@ TZS_YEAR=	2050
 TZS_CUTOFF_FLAG=	-c $(TZS_YEAR)
 TZS=		to$(TZS_YEAR).tzs
 TZS_NEW=	to$(TZS_YEAR)new.tzs
-TZS_DEPS=	$(YDATA) asctime.c localtime.c \
-			private.h tzfile.h zdump.c zic.c
+TZS_DEPS=	$(YDATA) localtime.c private.h \
+			strftime.c tzfile.h zdump.c zic.c
 TZDATA_DIST = $(COMMON) $(DATA) $(MISC)
 # EIGHT_YARDS is just a yard short of the whole ENCHILADA.
 EIGHT_YARDS = $(TZDATA_DIST) $(DOCS) $(SOURCES) tzdata.zi
@@ -855,10 +857,10 @@ tzselect:	tzselect.ksh version
 		chmod +x $@.out
 		mv $@.out $@
 
-check: check_mild back.ck
+check: check_mild back.ck now.ck
 check_mild: check_web check_zishrink \
   character-set.ck white-space.ck links.ck mainguard.ck \
-  name-lengths.ck now.ck slashed-abbrs.ck sorted.ck \
+  name-lengths.ck slashed-abbrs.ck sorted.ck \
   tables.ck ziguard.ck tzs.ck
 
 # True if UTF8_LOCALE does not work;
@@ -1103,7 +1105,7 @@ set-timestamps.out: $(EIGHT_YARDS)
 		   touch -md @1 test.out; then \
 		  rm -f test.out && \
 		  for file in $$files; do \
-		    if git diff --quiet $$file; then \
+		    if git diff --quiet HEAD $$file; then \
 		      time=$$(TZ=UTC0 git log -1 \
 			--format='tformat:%cd' \
 			--date='format:%Y-%m-%dT%H:%M:%SZ' \
@@ -1354,13 +1356,13 @@ long-long.ck unsigned.ck: $(VERSION_DEPS)
 zonenames:	tzdata.zi
 		@$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi
 
-asctime.o:	private.h tzfile.h
+asctime.o:	private.h
 date.o:		private.h
 difftime.o:	private.h
-localtime.o:	private.h tzfile.h tzdir.h
-strftime.o:	private.h tzfile.h
-zdump.o:	version.h
-zic.o:		private.h tzfile.h tzdir.h version.h
+localtime.o:	private.h tzdir.h tzfile.h
+strftime.o:	localtime.c private.h tzdir.h tzfile.h
+zdump.o:	private.h version.h
+zic.o:		private.h tzdir.h tzfile.h version.h
 
 .PHONY: ALL INSTALL all
 .PHONY: check check_mild check_time_t_alternatives

diff --git a/NEWS b/NEWS
@@ -1,5 +1,83 @@
 News for the tz database
 
+Release 2025a - 2025-01-15 10:47:24 -0800
+
+  Briefly:
+    Paraguay adopts permanent -03 starting spring 2024.
+    Improve pre-1991 data for the Philippines.
+    Etc/Unknown is now reserved.
+
+  Changes to future timestamps
+
+    Paraguay will stop changing its clocks after the spring-forward
+    transition on 2024-10-06, so it is now permanently at -03.
+    (Thanks to Heitor David Pinto and Even Scharning.)
+    This affects timestamps starting 2025-03-22, as well as the
+    obsolescent tm_isdst flags starting 2024-10-15.
+
+  Changes to past timestamps
+
+    Correct timestamps for the Philippines before 1900, and from 1937
+    through 1990.  (Thanks to P Chan for the heads-up and citations.)
+    This includes adjusting local mean time before 1899; fixing
+    transitions in September 1899, January 1937, and June 1954; adding
+    transitions in December 1941, November 1945, March and September
+    1977, and May and July 1990; and removing incorrect transitions in
+    March and September 1978.
+
+  Changes to data
+
+    Add zone1970.tab lines for the Concordia and Eyre Bird Observatory
+    research stations.  (Thanks to Derick Rethans and Jule Dabars.)
+
+  Changes to code
+
+    strftime %s now generates the correct numeric string even when the
+    represented number does not fit into time_t.  This is better than
+    generating the numeric equivalent of (time_t) -1, as strftime did
+    in TZDB releases 96a (when %s was introduced) through 2020a and in
+    releases 2022b through 2024b.  It is also better than failing and
+    returning 0, as strftime did in releases 2020b through 2022a.
+
+    strftime now outputs an invalid conversion specifier as-is,
+    instead of eliding the leading '%', which confused debugging.
+
+    An invalid TZ now generates the time zone abbreviation "-00", not
+    "UTC", to help the user see that an error has occurred.  (Thanks
+    to Arthur David Olson for suggesting a "wrong result".)
+
+    mktime and timeoff no longer incorrectly fail merely because a
+    struct tm component near INT_MIN or INT_MAX overflows when a
+    lower-order component carries into it.
+
+    TZNAME_MAXIMUM, the maximum number of bytes in a proleptic TZ
+    string's time zone abbreviation, now defaults to 254 not 255.
+    This helps reduce the size of internal state from 25480 to 21384
+    on common platforms.  This change should not be a problem, as
+    nobody uses such long "abbreviations" and the longstanding tzcode
+    maximum was 16 until release 2023a.  For those who prefer no
+    arbitrary limits, you can now specify TZNAME_MAXIMUM values up to
+    PTRDIFF_MAX, a limit forced by C anyway; formerly tzcode silently
+    misbehaved unless TZNAME_MAXIMUM was less than INT_MAX.
+
+    tzset and related functions no longer leak a file descriptor if
+    another thread forks or execs at about the same time and if the
+    platform has O_CLOFORK and O_CLOEXEC respectively.  Also, the
+    functions no longer let a TZif file become a controlling terminal.
+
+    'zdump -' now reads TZif data from /dev/stdin.
+    (From a question by Arthur David Olson.)
+
+  Changes to documentation
+
+    The name Etc/Unknown is now reserved: it will not be used by TZDB.
+    This is for compatibility with CLDR, which uses the string
+    "Etc/Unknown" for an unknown or invalid timezone.  (Thanks to
+    Justin Grant, Mark Davis, and Guy Harris.)
+
+    Cite Internet RFC 9636, which obsoletes RFC 8536 for TZif format.
+
+
 Release 2024b - 2024-09-04 12:27:47 -0700
 
   Briefly:
@@ -116,7 +194,7 @@ Release 2024b - 2024-09-04 12:27:47 -0700
   Changes to commentary
 
     Commentary about historical transitions in Portugal and her former
-    colonies has been expanded with links to many relevant legislation.
+    colonies has been expanded with links to relevant legislation.
     (Thanks to Tim Parenti.)
 
 
@@ -204,10 +282,10 @@ Release 2023d - 2023-12-21 20:02:24 -0800
     changing its time zone from -01/+00 to -02/-01 at the same moment
     as the spring-forward transition.  Its clocks will therefore not
     spring forward as previously scheduled.  The time zone change
-    reverts to its common practice before 1981.
+    reverts to its common practice before 1981.  (Thanks to Jule Dabars.)
 
     Fix predictions for DST transitions in Palestine in 2072-2075,
-    correcting a typo introduced in 2023a.
+    correcting a typo introduced in 2023a.  (Thanks to Jule Dabars.)
 
   Changes to past and future timestamps
 

diff --git a/antarctica b/antarctica
@@ -174,6 +174,8 @@ Zone Antarctica/Mawson	0	-	-00	1954 Feb 13
 
 # France & Italy - year-round base
 # Concordia, -750600+1232000, since 2005
+# https://en.wikipedia.org/wiki/Concordia_Station
+# Can use Asia/Singapore, which it has agreed with since inception.
 
 # Germany - year-round base
 # Neumayer III, -704080-0081602, since 2009

diff --git a/asctime.c b/asctime.c
@@ -7,6 +7,7 @@
 
 /*
 ** Avoid the temptation to punt entirely to strftime;
+** strftime can behave badly when tm components are out of range, and
 ** the output of strftime is supposed to be locale specific
 ** whereas the output of asctime is supposed to be constant.
 */
@@ -16,27 +17,6 @@
 #include "private.h"
 #include <stdio.h>
 
-/*
-** All years associated with 32-bit time_t values are exactly four digits long;
-** some years associated with 64-bit time_t values are not.
-** Vintage programs are coded for years that are always four digits long
-** and may assume that the newline always lands in the same place.
-** For years that are less than four digits, we pad the output with
-** leading zeroes to get the newline in the traditional place.
-** The -4 ensures that we get four characters of output even if
-** we call a strftime variant that produces fewer characters for some years.
-** This conforms to recent ISO C and POSIX standards, which say behavior
-** is undefined when the year is less than 1000 or greater than 9999.
-*/
-static char const ASCTIME_FMT[] = "%s %s%3d %.2d:%.2d:%.2d %-4s\n";
-/*
-** For years that are more than four digits we put extra spaces before the year
-** so that code trying to overwrite the newline won't end up overwriting
-** a digit within a year and truncating the year (operating on the assumption
-** that no output is better than wrong output).
-*/
-static char const ASCTIME_FMT_B[] = "%s %s%3d %.2d:%.2d:%.2d     %s\n";
-
 enum { STD_ASCTIME_BUF_SIZE = 26 };
 /*
 ** Big enough for something such as
@@ -50,14 +30,24 @@ enum { STD_ASCTIME_BUF_SIZE = 26 };
 */
 static char buf_asctime[2*3 + 5*INT_STRLEN_MAXIMUM(int) + 7 + 2 + 1 + 1];
 
-/* A similar buffer for ctime.
-   C89 requires that they be the same buffer.
-   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.  */
-#if SUPPORT_C89
-# define buf_ctime buf_asctime
-#else
-static char buf_ctime[sizeof buf_asctime];
+/* On pre-C99 platforms, a snprintf substitute good enough for us.  */
+#if !HAVE_SNPRINTF
+# include <stdarg.h>
+ATTRIBUTE_FORMAT((printf, 3, 4)) static int
+my_snprintf(char *s, size_t size, char const *format, ...)
+{
+  int n;
+  va_list args;
+  char stackbuf[sizeof buf_asctime];
+  va_start(args, format);
+  n = vsprintf(stackbuf, format, args);
+  va_end (args);
+  if (0 <= n && n < size)
+    memcpy (s, stackbuf, n + 1);
+  return n;
+}
+# undef snprintf
+# define snprintf my_snprintf
 #endif
 
 /* Publish asctime_r and ctime_r only when supporting older POSIX.  */
@@ -84,38 +74,59 @@ asctime_r(struct tm const *restrict timeptr, char *restrict buf)
 	};
 	register const char *	wn;
 	register const char *	mn;
-	char			year[INT_STRLEN_MAXIMUM(int) + 2];
-	char result[sizeof buf_asctime];
+	int year, mday, hour, min, sec;
+	long long_TM_YEAR_BASE = TM_YEAR_BASE;
+	size_t bufsize = (buf == buf_asctime
+			  ? sizeof buf_asctime : STD_ASCTIME_BUF_SIZE);
 
 	if (timeptr == NULL) {
+		strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+		/* Set errno now, since strcpy might change it in
+		   POSIX.1-2017 and earlier.  */
 		errno = EINVAL;
-		return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+		return buf;
 	}
 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
 		wn = "???";
 	else	wn = wday_name[timeptr->tm_wday];
 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
 		mn = "???";
 	else	mn = mon_name[timeptr->tm_mon];
-	/*
-	** Use strftime's %Y to generate the year, to avoid overflow problems
-	** when computing timeptr->tm_year + TM_YEAR_BASE.
-	** Assume that strftime is unaffected by other out-of-range members
-	** (e.g., timeptr->tm_mday) when processing "%Y".
-	*/
-	strftime(year, sizeof year, "%Y", timeptr);
-	/*
-	** We avoid using snprintf since it's not available on all systems.
-	*/
-	sprintf(result,
-		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
-		wn, mn,
-		timeptr->tm_mday, timeptr->tm_hour,
-		timeptr->tm_min, timeptr->tm_sec,
-		year);
-	if (strlen(result) < STD_ASCTIME_BUF_SIZE
-	    || buf == buf_ctime || buf == buf_asctime)
-		return strcpy(buf, result);
+
+	year = timeptr->tm_year;
+	mday = timeptr->tm_mday;
+	hour = timeptr->tm_hour;
+	min = timeptr->tm_min;
+	sec = timeptr->tm_sec;
+
+	/* Vintage programs are coded for years that are always four bytes long
+	   and may assume that the newline always lands in the same place.
+	   For years that are less than four bytes, pad the output with
+	   leading zeroes to get the newline in the traditional place.
+	   For years longer than four bytes, put extra spaces before the year
+	   so that vintage code trying to overwrite the newline
+	   won't overwrite a digit within a year and truncate the year,
+	   using the principle that no output is better than wrong output.
+	   This conforms to ISO C and POSIX standards, which say behavior
+	   is undefined when the year is less than 1000 or greater than 9999.
+
+	   Also, avoid overflow when formatting tm_year + TM_YEAR_BASE.  */
+
+	if ((year <= LONG_MAX - TM_YEAR_BASE
+	     ? snprintf (buf, bufsize,
+			 ((-999 - TM_YEAR_BASE <= year
+			   && year <= 9999 - TM_YEAR_BASE)
+			  ? "%s %s%3d %.2d:%.2d:%.2d %04ld\n"
+			  : "%s %s%3d %.2d:%.2d:%.2d     %ld\n"),
+			 wn, mn, mday, hour, min, sec,
+			 year + long_TM_YEAR_BASE)
+	     : snprintf (buf, bufsize,
+			 "%s %s%3d %.2d:%.2d:%.2d     %d%d\n",
+			 wn, mn, mday, hour, min, sec,
+			 year / 10 + TM_YEAR_BASE / 10,
+			 year % 10))
+	    < bufsize)
+		return buf;
 	else {
 		errno = EOVERFLOW;
 		return NULL;
@@ -140,5 +151,8 @@ ctime_r(const time_t *timep, char *buf)
 char *
 ctime(const time_t *timep)
 {
-  return ctime_r(timep, buf_ctime);
+  /* Do not call localtime_r, as C23 requires ctime to initialize the
+     static storage that localtime updates.  */
+  struct tm *tmp = localtime(timep);
+  return tmp ? asctime(tmp) : NULL;
 }