[[PATCH RFC 2] 03/63] Y2038: make __tz_convert compatible with 64-bit-time

["Albert ARIBAUD (3ADEV)" <albert.aribaud@3adev.fr>]

__tz_convert is used by six API functions. Making
it compatible with 64-bit time allows reusing it for
implementing 64-bit-time versions of theses six APIs.
---
 include/time.h   | 12 ++++++------
 time/gmtime.c    | 15 +++++++++++++--
 time/localtime.c | 15 +++++++++++++--
 time/offtime.c   |  8 ++++----
 time/tzfile.c    |  4 ++--
 time/tzset.c     | 24 +++++++++---------------
 6 files changed, 47 insertions(+), 31 deletions(-)

diff --git a/include/time.h b/include/time.h
index ba2c67a829..6ffa9b2efc 100644
--- a/include/time.h
+++ b/include/time.h
@@ -40,14 +40,14 @@ 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
@@ -64,11 +64,11 @@ extern struct tm *__gmtime_r (const time_t *__restrict __timer,
 			      struct tm *__restrict __tp);
 libc_hidden_proto (__gmtime_r)
 
-/* Compute the `struct tm' representation of *T,
+/* 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 __time64_t __timer,
 		      long int __offset,
 		      struct tm *__tp) attribute_hidden;
 
@@ -77,8 +77,8 @@ extern char *__asctime_r (const struct tm *__tp, char *__buf)
 extern void __tzset (void) attribute_hidden;
 
 /* 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 __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/gmtime.c b/time/gmtime.c
index dc33b3e68a..e38f0cbcc0 100644
--- a/time/gmtime.c
+++ b/time/gmtime.c
@@ -17,13 +17,19 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <time.h>
+#include <errno.h>
 
 /* Return the `struct tm' representation of *T in UTC,
    using *TP to store the result.  */
 struct tm *
 __gmtime_r (const time_t *t, struct tm *tp)
 {
-  return __tz_convert (t, 0, tp);
+  if (t == NULL)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+  return __tz_convert (*t, 0, tp);
 }
 libc_hidden_def (__gmtime_r)
 weak_alias (__gmtime_r, gmtime_r)
@@ -33,5 +39,10 @@ weak_alias (__gmtime_r, gmtime_r)
 struct tm *
 gmtime (const time_t *t)
 {
-  return __tz_convert (t, 0, &_tmbuf);
+  if (t == NULL)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+  return __tz_convert (*t, 0, &_tmbuf);
 }
diff --git a/time/localtime.c b/time/localtime.c
index 8684a8a971..362fdb3c21 100644
--- a/time/localtime.c
+++ b/time/localtime.c
@@ -17,6 +17,7 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <time.h>
+#include <errno.h>
 
 /* The C Standard says that localtime and gmtime return the same pointer.  */
 struct tm _tmbuf;
@@ -27,7 +28,12 @@ struct tm _tmbuf;
 struct tm *
 __localtime_r (const time_t *t, struct tm *tp)
 {
-  return __tz_convert (t, 1, tp);
+  if (t == NULL)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+  return __tz_convert (*t, 1, tp);
 }
 weak_alias (__localtime_r, localtime_r)
 
@@ -36,6 +42,11 @@ weak_alias (__localtime_r, localtime_r)
 struct tm *
 localtime (const time_t *t)
 {
-  return __tz_convert (t, 1, &_tmbuf);
+  if (t == NULL)
+    {
+      __set_errno (EINVAL);
+      return NULL;
+    }
+  return __tz_convert (*t, 1, &_tmbuf);
 }
 libc_hidden_def (localtime)
diff --git a/time/offtime.c b/time/offtime.c
index 04c48389fc..59ed38f9fa 100644
--- a/time/offtime.c
+++ b/time/offtime.c
@@ -21,18 +21,18 @@
 #define	SECS_PER_HOUR	(60 * 60)
 #define	SECS_PER_DAY	(SECS_PER_HOUR * 24)
 
-/* Compute the `struct tm' representation of *T,
+/* 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.  */
 int
-__offtime (const time_t *t, long int offset, struct tm *tp)
+__offtime (const __time64_t t, long int offset, struct tm *tp)
 {
   time_t days, rem, y;
   const unsigned short int *ip;
 
-  days = *t / SECS_PER_DAY;
-  rem = *t % SECS_PER_DAY;
+  days = t / SECS_PER_DAY;
+  rem = t % SECS_PER_DAY;
   rem += offset;
   while (rem < 0)
     {
diff --git a/time/tzfile.c b/time/tzfile.c
index 3e39723148..9560eda8b4 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -630,7 +630,7 @@ __tzfile_default (const char *std, const char *dst,
 }
 \f
 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 (! __offtime (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..efbb47716f 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -16,7 +16,6 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <ctype.h>
-#include <errno.h>
 #include <libc-lock.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -55,7 +54,7 @@ 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 +415,7 @@ 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 +513,10 @@ 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);
@@ -562,20 +562,14 @@ __tzset (void)
 }
 weak_alias (__tzset, tzset)
 \f
-/* Return the `struct tm' representation of *TIMER in the local timezone.
+/* Return the `struct tm' representation of TIMER in the local timezone.
    Use local time if USE_LOCALTIME is nonzero, UTC otherwise.  */
 struct tm *
-__tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
+__tz_convert (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.
@@ -584,14 +578,14 @@ __tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
   tzset_internal (tp == &_tmbuf && use_localtime);
 
   if (__use_tzfile)
-    __tzfile_compute (*timer, use_localtime, &leap_correction,
+    __tzfile_compute (timer, use_localtime, &leap_correction,
 		      &leap_extra_secs, tp);
   else
     {
       if (! __offtime (timer, 0, tp))
 	tp = NULL;
       else
-	__tz_compute (*timer, tp, use_localtime);
+	__tz_compute (timer, tp, use_localtime);
       leap_correction = 0L;
       leap_extra_secs = 0;
     }
-- 
2.14.1