Y2038: make __tz_convert compatible with 64-bit-timeaaribaud/tmp

This implies that its callers be 64-bit-time compatible too.
It is done by creating 64-bit-time versions of these and
turning their original 32-bit-time versions into wrappers
(at a slight execution time cost).

The callers affected are:

  * localtime
  * localtime_r
  * ctime
  * ctime_r
  * gmtime
  * gmtime_r

Note that in time/tzfile.c we do not need to check for time_t
overflows anymore as introduced by commit fc79706a323 since we
now use internal_time_t.

1 files changed, 35 insertions, 5 deletions

diff --git a/time/gmtime.c b/time/gmtime.c
index dc33b3e68a..689784d22e 100644
--- a/time/gmtime.c
+++ b/time/gmtime.c
@@ -17,21 +17,51 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <time.h>
+#include <errno.h>
+
+/* 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_convert (*t, 0, tp);
+}
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
 
-/* 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);
+  __time64_t t64 = *t;
+  return __gmtime64_r (&t64, tp);
 }
+
+#endif
+
+/* This always works because either __TIMESIZE != 64 and __gmtime_r exists
+   or __TIMESIZE == 64 and the definition of __gmtime64_r above actually
+   defined __gmtime_r.  */
 libc_hidden_def (__gmtime_r)
 weak_alias (__gmtime_r, gmtime_r)
 
+/* Return the `struct tm' representation of 64-bit-time *T in UTC.	*/
+struct tm *
+__gmtime64 (const __time64_t *t)
+{
+  return __tz_convert (*t, 0, &_tmbuf);
+}
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
 
-/* Return the `struct tm' representation of *T in UTC.	*/
 struct tm *
 gmtime (const time_t *t)
 {
-  return __tz_convert (t, 0, &_tmbuf);
+  __time64_t t64 = *t;
+  return __gmtime64 (&t64);
 }
+
+#endif