1 files changed, 87 insertions, 39 deletions

diff --git a/src/timezone/localtime.c b/src/timezone/localtime.c
index e3029d841d7..96e62aff3b4 100644
--- a/src/timezone/localtime.c
+++ b/src/timezone/localtime.c
@@ -1,3 +1,5 @@
+/* Convert timestamp from pg_time_t to struct pg_tm.  */
+
 /*
  * This file is in the public domain, so clarified as of
  * 1996-06-05 by Arthur David Olson.
@@ -117,7 +119,7 @@ init_ttinfo(struct ttinfo *s, int32 gmtoff, bool isdst, int abbrind)
 }
 
 static int32
-detzcode(const char *codep)
+detzcode(const char *const codep)
 {
 	int32		result;
 	int			i;
@@ -143,7 +145,7 @@ detzcode(const char *codep)
 }
 
 static int64
-detzcode64(const char *codep)
+detzcode64(const char *const codep)
 {
 	uint64		result;
 	int			i;
@@ -258,8 +260,13 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 		int32		charcnt = detzcode(up->tzhead.tzh_charcnt);
 		char const *p = up->buf + tzheadsize;
 
+		/*
+		 * Although tzfile(5) currently requires typecnt to be nonzero,
+		 * support future formats that may allow zero typecnt in files that
+		 * have a TZ string and no transitions.
+		 */
 		if (!(0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
-			  && 0 < typecnt && typecnt < TZ_MAX_TYPES
+			  && 0 <= typecnt && typecnt < TZ_MAX_TYPES
 			  && 0 <= timecnt && timecnt < TZ_MAX_TIMES
 			  && 0 <= charcnt && charcnt < TZ_MAX_CHARS
 			  && (ttisstdcnt == typecnt || ttisstdcnt == 0)
@@ -416,8 +423,7 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 		struct state *ts = &lsp->u.st;
 
 		up->buf[nread - 1] = '\0';
-		if (tzparse(&up->buf[1], ts, false)
-			&& ts->typecnt == 2)
+		if (tzparse(&up->buf[1], ts, false))
 		{
 			/*
 			 * Attempt to reuse existing abbreviations. Without this,
@@ -430,7 +436,7 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 			int			gotabbr = 0;
 			int			charcnt = sp->charcnt;
 
-			for (i = 0; i < 2; i++)
+			for (i = 0; i < ts->typecnt; i++)
 			{
 				char	   *tsabbr = ts->chars + ts->ttis[i].tt_abbrind;
 				int			j;
@@ -455,7 +461,7 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 					}
 				}
 			}
-			if (gotabbr == 2)
+			if (gotabbr == ts->typecnt)
 			{
 				sp->charcnt = charcnt;
 
@@ -470,7 +476,8 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 					sp->timecnt--;
 
 				for (i = 0; i < ts->timecnt; i++)
-					if (sp->ats[sp->timecnt - 1] < ts->ats[i])
+					if (sp->timecnt == 0
+						|| sp->ats[sp->timecnt - 1] < ts->ats[i])
 						break;
 				while (i < ts->timecnt
 					   && sp->timecnt < TZ_MAX_TIMES)
@@ -481,11 +488,13 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 					sp->timecnt++;
 					i++;
 				}
-				sp->ttis[sp->typecnt++] = ts->ttis[0];
-				sp->ttis[sp->typecnt++] = ts->ttis[1];
+				for (i = 0; i < ts->typecnt; i++)
+					sp->ttis[sp->typecnt++] = ts->ttis[i];
 			}
 		}
 	}
+	if (sp->typecnt == 0)
+		return EINVAL;
 	if (sp->timecnt > 1)
 	{
 		for (i = 1; i < sp->timecnt; ++i)
@@ -507,6 +516,18 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 	}
 
 	/*
+	 * 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 is unused in transitions, it's the type to use for early
 	 * times.
 	 */
@@ -529,6 +550,11 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 	}
 
 	/*
+	 * 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.
 	 */
@@ -542,7 +568,14 @@ tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
 				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;
 }
 
@@ -601,10 +634,11 @@ static const int year_lengths[2] = {
 };
 
 /*
- * Given a pointer into a time zone string, scan until a character that is not
- * a valid character in a zone name is found. Return a pointer to that
- * character.
+ * Given a pointer into a timezone string, scan until a character that is not
+ * a valid character in a time zone abbreviation is found.
+ * Return a pointer to that character.
  */
+
 static const char *
 getzname(const char *strp)
 {
@@ -617,15 +651,17 @@ getzname(const char *strp)
 }
 
 /*
- * Given a pointer into an extended time zone string, scan until the ending
- * delimiter of the zone name is located. Return a pointer to the delimiter.
+ * Given a pointer into an extended timezone string, scan until the ending
+ * delimiter of the time zone abbreviation is located.
+ * Return a pointer to the delimiter.
  *
  * As with getzname above, the legal character set is actually quite
  * restricted, with other characters producing undefined results.
  * We don't do any checking here; checking is done later in common-case code.
  */
+
 static const char *
-getqzname(const char *strp, int delim)
+getqzname(const char *strp, const int delim)
 {
 	int			c;
 
@@ -635,13 +671,14 @@ getqzname(const char *strp, int delim)
 }
 
 /*
- * Given a pointer into a time zone string, extract a number from that string.
+ * Given a pointer into a timezone string, extract a number from that string.
  * Check that the number is within a specified range; if it is not, return
  * NULL.
  * Otherwise, return a pointer to the first character not part of the number.
  */
+
 static const char *
-getnum(const char *strp, int *nump, int min, int max)
+getnum(const char *strp, int *const nump, const int min, const int max)
 {
 	char		c;
 	int			num;
@@ -663,14 +700,15 @@ getnum(const char *strp, int *nump, int min, int max)
 }
 
 /*
- * Given a pointer into a time zone string, extract a number of seconds,
+ * Given a pointer into a timezone string, extract a number of seconds,
  * in hh[:mm[:ss]] form, from the string.
  * If any error occurs, return NULL.
  * Otherwise, return a pointer to the first character not part of the number
  * of seconds.
  */
+
 static const char *
-getsecs(const char *strp, int32 *secsp)
+getsecs(const char *strp, int32 *const secsp)
 {
 	int			num;
 
@@ -704,13 +742,14 @@ getsecs(const char *strp, int32 *secsp)
 }
 
 /*
- * Given a pointer into a time zone string, extract an offset, in
+ * Given a pointer into a timezone string, extract an offset, in
  * [+-]hh[:mm[:ss]] form, from the string.
  * If any error occurs, return NULL.
  * Otherwise, return a pointer to the first character not part of the time.
  */
+
 static const char *
-getoffset(const char *strp, int32 *offsetp)
+getoffset(const char *strp, int32 *const offsetp)
 {
 	bool		neg = false;
 
@@ -730,13 +769,14 @@ getoffset(const char *strp, int32 *offsetp)
 }
 
 /*
- * Given a pointer into a time zone string, extract a rule in the form
+ * Given a pointer into a timezone string, extract a rule in the form
  * date[/time]. See POSIX section 8 for the format of "date" and "time".
  * If a valid rule is not found, return NULL.
  * Otherwise, return a pointer to the first character not part of the rule.
  */
+
 static const char *
-getrule(const char *strp, struct rule *rulep)
+getrule(const char *strp, struct rule *const rulep)
 {
 	if (*strp == 'J')
 	{
@@ -795,9 +835,10 @@ getrule(const char *strp, struct rule *rulep)
  * Given a year, a rule, and the offset from UT at the time that rule takes
  * effect, calculate the year-relative time that rule takes effect.
  */
+
 static int32
-transtime(int year, const struct rule *rulep,
-		  int32 offset)
+transtime(const int year, const struct rule *const rulep,
+		  const int32 offset)
 {
 	bool		leapyear;
 	int32		value;
@@ -967,7 +1008,7 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 		{
 			dstname = name;
 			name = getzname(name);
-			dstlen = name - dstname;	/* length of DST zone name */
+			dstlen = name - dstname;	/* length of DST abbr. */
 		}
 		if (!dstlen)
 			return false;
@@ -1039,8 +1080,8 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 			/*
 			 * Two transitions per year, from EPOCH_YEAR forward.
 			 */
-			init_ttinfo(&sp->ttis[0], -dstoffset, true, stdlen + 1);
-			init_ttinfo(&sp->ttis[1], -stdoffset, false, 0);
+			init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+			init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
 			sp->defaulttype = 0;
 			timecnt = 0;
 			janfirst = 0;
@@ -1089,19 +1130,15 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 					if (!increment_overflow_time
 						(&sp->ats[timecnt],
 						 janoffset + starttime))
-						sp->types[timecnt++] = reversed;
-					else if (janoffset)
-						sp->defaulttype = reversed;
+						sp->types[timecnt++] = !reversed;
 					sp->ats[timecnt] = janfirst;
 					if (!increment_overflow_time
 						(&sp->ats[timecnt],
 						 janoffset + endtime))
 					{
-						sp->types[timecnt++] = !reversed;
+						sp->types[timecnt++] = reversed;
 						yearlim = year + YEARSPERREPEAT + 1;
 					}
-					else if (janoffset)
-						sp->defaulttype = !reversed;
 				}
 				if (increment_overflow_time
 					(&janfirst, janoffset + yearsecs))
@@ -1110,7 +1147,10 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 			}
 			sp->timecnt = timecnt;
 			if (!timecnt)
+			{
+				sp->ttis[0] = sp->ttis[1];
 				sp->typecnt = 1;	/* Perpetual DST.  */
+			}
 			else if (YEARSPERREPEAT < year - yearbeg)
 				sp->goback = sp->goahead = true;
 		}
@@ -1179,7 +1219,6 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 					 * otherwise, add the standard time offset to the
 					 * transition time.
 					 */
-
 					/*
 					 * Transitions from DST to DDST will effectively disappear
 					 * since POSIX provides for only one DST offset.
@@ -1233,7 +1272,7 @@ tzparse(const char *name, struct state *sp, bool lastditch)
 }
 
 static void
-gmtload(struct state *sp)
+gmtload(struct state *const sp)
 {
 	if (tzload(gmt, NULL, sp, true) != 0)
 		tzparse(gmt, sp, true);
@@ -1248,7 +1287,7 @@ gmtload(struct state *sp)
  */
 static struct pg_tm *
 localsub(struct state const *sp, pg_time_t const *timep,
-		 struct pg_tm *tmp)
+		 struct pg_tm *const tmp)
 {
 	const struct ttinfo *ttisp;
 	int			i;
@@ -1316,6 +1355,11 @@ localsub(struct state const *sp, pg_time_t const *timep,
 	}
 	ttisp = &sp->ttis[i];
 
+	/*
+	 * To get (wrong) behavior that's compatible with System V Release 2.0
+	 * you'd replace the statement below with t += ttisp->tt_gmtoff;
+	 * timesub(&t, 0L, sp, tmp);
+	 */
 	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
 	if (result)
 	{
@@ -1338,8 +1382,10 @@ pg_localtime(const pg_time_t *timep, const pg_tz *tz)
  *
  * Except we have a private "struct state" for GMT, so no sp is passed in.
  */
+
 static struct pg_tm *
-gmtsub(pg_time_t const *timep, int32 offset, struct pg_tm *tmp)
+gmtsub(pg_time_t const *timep, int32 offset,
+	   struct pg_tm *tmp)
 {
 	struct pg_tm *result;
 
@@ -1354,6 +1400,7 @@ gmtsub(pg_time_t const *timep, int32 offset, struct pg_tm *tmp)
 			return NULL;		/* errno should be set by malloc */
 		gmtload(gmtptr);
 	}
+
 	result = timesub(timep, offset, gmtptr, tmp);
 
 	/*
@@ -1378,6 +1425,7 @@ pg_gmtime(const pg_time_t *timep)
  * Return the number of leap years through the end of the given year
  * where, to make the math easy, the answer for year zero is defined as zero.
  */
+
 static int
 leaps_thru_end_of_nonneg(int y)
 {