Y2038: add functions which have struct tm arguments

This consists in the following implementation additions:

([file] 32-bit implementation -> [file] 64-bit addition)

time/ctime.c ctime() -> __ctime64()
time/ctime_r.c ctime_r() -> __ctime64_r()
time/gmtime.c gmtime() -> __gmtime64()
time/gmtime.c gmtime_r() -> __gmtime64_r()
time/localtime.c localtime() -> __localtime64()
time/localtime.c localtime_r() -> __localtime64_r()

which require the following internal function additions

time/offtime.c __offtime() -> __offtime64()
time/tzset.c __tz_convert() -> __tz64_convert()

and internal function (32-bit-time-compatible) changes

time/tzfile.c __tzfile_compute()
time/tzset.c tzset_internal()
time/tzset.c compute_change()

10 files changed, 209 insertions, 12 deletions

diff --git a/include/sys/time.h b/include/sys/time.h
index 98f6b6b2cc..fa8e33fef8 100644
--- a/include/sys/time.h
+++ b/include/sys/time.h
@@ -39,5 +39,6 @@ extern int __utimes (const char *__file, const struct timeval __tvp[2])
 	attribute_hidden;
 extern int __futimes (int fd, const struct timeval tvp[2]) attribute_hidden;
 
+extern struct tm * __localtime64 (const __time64_t *__timer);
 # endif
 #endif
diff --git a/include/time.h b/include/time.h
index 7eda265a66..894dcdb0b3 100644
--- a/include/time.h
+++ b/include/time.h
@@ -9,6 +9,8 @@ extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
 extern __typeof (strptime_l) __strptime_l;
 
+extern struct tm *__localtime64 (const __time64_t *__timer);
+
 libc_hidden_proto (time)
 libc_hidden_proto (asctime)
 libc_hidden_proto (mktime)
@@ -17,6 +19,8 @@ libc_hidden_proto (localtime)
 libc_hidden_proto (strftime)
 libc_hidden_proto (strptime)
 
+libc_hidden_proto (__localtime64)
+
 extern __typeof (clock_getres) __clock_getres;
 extern __typeof (clock_gettime) __clock_gettime;
 libc_hidden_proto (__clock_gettime)
@@ -40,14 +44,14 @@ extern int __use_tzfile attribute_hidden;
 
 extern void __tzfile_read (const char *file, size_t extra,
 			   char **extrap) attribute_hidden;
-extern void __tzfile_compute (time_t timer, int use_localtime,
+extern void __tzfile_compute (__time64_t timer, int use_localtime,
 			      long int *leap_correct, int *leap_hit,
 			      struct tm *tp) attribute_hidden;
 extern void __tzfile_default (const char *std, const char *dst,
 			      long int stdoff, long int dstoff)
   attribute_hidden;
 extern void __tzset_parse_tz (const char *tz) attribute_hidden;
-extern void __tz_compute (time_t timer, struct tm *tm, int use_localtime)
+extern void __tz_compute (__time64_t timer, struct tm *tm, int use_localtime)
   __THROW attribute_hidden;
 
 /* Subroutine of `mktime'.  Return the `time_t' representation of TP and
@@ -60,15 +64,21 @@ extern time_t __mktime_internal (struct tm *__tp,
 extern struct tm *__localtime_r (const time_t *__timer,
 				 struct tm *__tp) attribute_hidden;
 
-extern struct tm *__gmtime_r (const time_t *__restrict __timer,
+extern struct tm *__localtime64_r (const __time64_t *__timer,
+				   struct tm *__tp) attribute_hidden;
+
+extern struct tm *__gmtime_r (const __time_t *__restrict __timer,
 			      struct tm *__restrict __tp);
 libc_hidden_proto (__gmtime_r)
 
+extern struct tm *__gmtime64_r (const __time64_t *__restrict __timer,
+			        struct tm *__restrict __tp);
+
 /* Compute the `struct tm' representation of *T,
    offset OFFSET seconds east of UTC,
    and store year, yday, mon, mday, wday, hour, min, sec into *TP.
    Return nonzero if successful.  */
-extern int __offtime (const time_t *__timer,
+extern int __offtime (const __time_t *__timer,
 		      long int __offset,
 		      struct tm *__tp) attribute_hidden;
 
@@ -76,9 +86,21 @@ extern char *__asctime_r (const struct tm *__tp, char *__buf)
   attribute_hidden;
 extern void __tzset (void) attribute_hidden;
 
+extern int __offtime64 (const __time64_t *__timer,
+		        long int __offset,
+		        struct tm *__tp)
+  attribute_hidden;
+
+extern char *__asctime_r (const struct tm *__tp, char *__buf);
+extern void __tzset (void);
+
 /* Prototype for the internal function to get information based on TZ.  */
-extern struct tm *__tz_convert (const time_t *timer, int use_localtime,
-				struct tm *tp) attribute_hidden;
+extern struct tm *__tz_convert (const __time_t *timer, int use_localtime,
+			        struct tm *tp) attribute_hidden;
+
+extern struct tm *__tz_convert64 (const __time64_t *timer,
+				  int use_localtime, struct tm *tp)
+  attribute_hidden;
 
 extern int __nanosleep (const struct timespec *__requested_time,
 			struct timespec *__remaining);
diff --git a/time/Versions b/time/Versions
index 57314b98c8..0ad2749f2c 100644
--- a/time/Versions
+++ b/time/Versions
@@ -67,5 +67,8 @@ libc {
   }
   GLIBC_2.27 {
     __difftime64;
+    __ctime64; __ctime64_r;
+    __gmtime64; __gmtime64_r;
+    __localtime64; __localtime64_r;
   }
 }
diff --git a/time/ctime.c b/time/ctime.c
index 1222614f29..fbfb61fcd6 100644
--- a/time/ctime.c
+++ b/time/ctime.c
@@ -26,3 +26,13 @@ ctime (const time_t *t)
      In particular, ctime and asctime must yield the same pointer.  */
   return asctime (localtime (t));
 }
+
+/* Return a string as returned by asctime which
+   is the representation of *T in that form.  */
+char *
+__ctime64 (const __time64_t *t)
+{
+  /* Apply the same rule as ctime:
+     make ctime64 (t) is equivalent to asctime (localtime64 (t)).  */
+  return asctime (__localtime64 (t));
+}
diff --git a/time/ctime_r.c b/time/ctime_r.c
index c111146d76..742a967fdd 100644
--- a/time/ctime_r.c
+++ b/time/ctime_r.c
@@ -27,3 +27,12 @@ ctime_r (const time_t *t, char *buf)
   struct tm tm;
   return __asctime_r (__localtime_r (t, &tm), buf);
 }
+
+/* Return a string as returned by asctime which is the representation
+   of *T in that form.  Reentrant Y2038-proof version.  */
+char *
+__ctime64_r (const __time64_t *t, char *buf)
+{
+  struct tm tm;
+  return __asctime_r (__localtime64_r (t, &tm), buf);
+}
diff --git a/time/gmtime.c b/time/gmtime.c
index dc33b3e68a..6d6878a1ea 100644
--- a/time/gmtime.c
+++ b/time/gmtime.c
@@ -35,3 +35,18 @@ gmtime (const time_t *t)
 {
   return __tz_convert (t, 0, &_tmbuf);
 }
+
+/* Return the `struct tm' representation of 64-bit-time *T
+   in UTC, using *TP to store the result.  */
+struct tm *
+__gmtime64_r (const __time64_t *t, struct tm *tp)
+{
+  return __tz_convert64 (t, 0, tp);
+}
+
+/* Return the `struct tm' representation of 64-bit-time *T in UTC.	*/
+struct tm *
+__gmtime64 (const __time64_t *t)
+{
+  return __tz_convert64 (t, 0, &_tmbuf);
+}
diff --git a/time/localtime.c b/time/localtime.c
index 8684a8a971..63dd125638 100644
--- a/time/localtime.c
+++ b/time/localtime.c
@@ -39,3 +39,20 @@ localtime (const time_t *t)
   return __tz_convert (t, 1, &_tmbuf);
 }
 libc_hidden_def (localtime)
+
+/* 64-bit-time versions */
+
+/* Return the `struct tm' representation of *T in local time,
+   using *TP to store the result.  */
+struct tm *
+__localtime64_r (const __time64_t *t, struct tm *tp)
+{
+  return __tz_convert64 (t, 1, tp);
+}
+
+/* Return the `struct tm' representation of *T in local time.  */
+struct tm *
+__localtime64 (const __time64_t *t)
+{
+  return __tz_convert64 (t, 1, &_tmbuf);
+}
diff --git a/time/offtime.c b/time/offtime.c
index 04c48389fc..650ddcce38 100644
--- a/time/offtime.c
+++ b/time/offtime.c
@@ -84,3 +84,67 @@ __offtime (const time_t *t, long int offset, struct tm *tp)
   tp->tm_mday = days + 1;
   return 1;
 }
+
+/* Compute the `struct tm' representation of 64-bit-time *T,
+   offset OFFSET seconds east of UTC,
+   and store year, yday, mon, mday, wday, hour, min, sec into *TP.
+   Return nonzero if successful.  */
+int
+__offtime64 (const __time64_t *t, long int offset, struct tm *tp)
+{
+  __time64_t days, rem, y;
+  const unsigned short int *ip;
+
+  days = *t / SECS_PER_DAY;
+  rem = *t % SECS_PER_DAY;
+  rem += offset;
+  while (rem < 0)
+    {
+      rem += SECS_PER_DAY;
+      --days;
+    }
+  while (rem >= SECS_PER_DAY)
+    {
+      rem -= SECS_PER_DAY;
+      ++days;
+    }
+  tp->tm_hour = rem / SECS_PER_HOUR;
+  rem %= SECS_PER_HOUR;
+  tp->tm_min = rem / 60;
+  tp->tm_sec = rem % 60;
+  /* January 1, 1970 was a Thursday.  */
+  tp->tm_wday = (4 + days) % 7;
+  if (tp->tm_wday < 0)
+    tp->tm_wday += 7;
+  y = 1970;
+
+#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
+#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
+
+  while (days < 0 || days >= (__isleap (y) ? 366 : 365))
+    {
+      /* Guess a corrected year, assuming 365 days per year.  */
+      __time64_t yg = y + days / 365 - (days % 365 < 0);
+
+      /* Adjust DAYS and Y to match the guessed year.  */
+      days -= ((yg - y) * 365
+	       + LEAPS_THRU_END_OF (yg - 1)
+	       - LEAPS_THRU_END_OF (y - 1));
+      y = yg;
+    }
+  tp->tm_year = y - 1900;
+  if (tp->tm_year != y - 1900)
+    {
+      /* The year cannot be represented due to overflow.  */
+      __set_errno (EOVERFLOW);
+      return 0;
+    }
+  tp->tm_yday = days;
+  ip = __mon_yday[__isleap(y)];
+  for (y = 11; days < (long int) ip[y]; --y)
+    continue;
+  days -= ip[y];
+  tp->tm_mon = y;
+  tp->tm_mday = days + 1;
+  return 1;
+}
diff --git a/time/tzfile.c b/time/tzfile.c
index 1e59fd5abc..8ec9834d28 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -630,7 +630,7 @@ __tzfile_default (const char *std, const char *dst,
 }
 
 void
-__tzfile_compute (time_t timer, int use_localtime,
+__tzfile_compute (__time64_t timer, int use_localtime,
 		  long int *leap_correct, int *leap_hit,
 		  struct tm *tp)
 {
@@ -685,7 +685,7 @@ __tzfile_compute (time_t timer, int use_localtime,
 
 	  /* Convert to broken down structure.  If this fails do not
 	     use the string.  */
-	  if (__glibc_unlikely (! __offtime (&timer, 0, tp)))
+	  if (__glibc_unlikely (! __offtime64 (&timer, 0, tp)))
 	    goto use_last;
 
 	  /* Use the rules from the TZ string to compute the change.  */
diff --git a/time/tzset.c b/time/tzset.c
index b51786704a..106966f4dd 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -55,7 +55,7 @@ typedef struct
 
     /* We cache the computed time of change for a
        given year so we don't have to recompute it.  */
-    time_t change;	/* When to change to this zone.  */
+    __time64_t change;	/* When to change to this zone.  */
     int computed_for;	/* Year above is computed for.  */
   } tz_rule;
 
@@ -416,7 +416,7 @@ tzset_internal (int always)
       tz_rules[0].name = tz_rules[1].name = "UTC";
       if (J0 != 0)
 	tz_rules[0].type = tz_rules[1].type = J0;
-      tz_rules[0].change = tz_rules[1].change = (time_t) -1;
+      tz_rules[0].change = tz_rules[1].change = (__time64_t) -1;
       update_vars ();
       return;
     }
@@ -514,9 +514,10 @@ compute_change (tz_rule *rule, int year)
 
 
 /* Figure out the correct timezone for TM and set `__tzname',
-   `__timezone', and `__daylight' accordingly.  */
+   `__timezone', and `__daylight' accordingly.
+   NOTE: this takes a __time64_t value, so passing a __time_t value is OK. */
 void
-__tz_compute (time_t timer, struct tm *tm, int use_localtime)
+__tz_compute (__time64_t timer, struct tm *tm, int use_localtime)
 {
   compute_change (&tz_rules[0], 1900 + tm->tm_year);
   compute_change (&tz_rules[1], 1900 + tm->tm_year);
@@ -617,6 +618,61 @@ __tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
 }
 
 
+/* Return the `struct tm' representation of *TIMER in the local timezone.
+   Use local time if USE_LOCALTIME is nonzero, UTC otherwise.  */
+struct tm *
+__tz_convert64 (const __time64_t *timer, int use_localtime, struct tm *tp)
+{
+  long int leap_correction;
+  int leap_extra_secs;
+
+  if (timer == NULL)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+
+  __libc_lock_lock (tzset_lock);
+
+  /* Update internal database according to current TZ setting.
+     POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
+     This is a good idea since this allows at least a bit more parallelism.  */
+  tzset_internal (tp == &_tmbuf && use_localtime);
+
+  if (__use_tzfile)
+    __tzfile_compute (*timer, use_localtime, &leap_correction,
+		      &leap_extra_secs, tp);
+  else
+    {
+      if (! __offtime64 (timer, 0, tp))
+	tp = NULL;
+      else
+	__tz_compute (*timer, tp, use_localtime);
+      leap_correction = 0L;
+      leap_extra_secs = 0;
+    }
+
+  __libc_lock_unlock (tzset_lock);
+
+  if (tp)
+    {
+      if (! use_localtime)
+	{
+	  tp->tm_isdst = 0;
+	  tp->tm_zone = "GMT";
+	  tp->tm_gmtoff = 0L;
+	}
+
+      if (__offtime64 (timer, tp->tm_gmtoff - leap_correction, tp))
+        tp->tm_sec += leap_extra_secs;
+      else
+	tp = NULL;
+    }
+
+  return tp;
+}
+
+
 libc_freeres_fn (free_mem)
 {
   while (tzstring_list != NULL)