Patchwork [v9,2/2] Y2038: make __tz_convert compatible with 64-bit-time

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Submitter Albert ARIBAUD
Date Oct. 10, 2018, 12:12 p.m.
Message ID <20181010121242.13902-2-albert.aribaud@3adev.fr>
Download mbox | patch
Permalink /patch/29693/
State New
Headers show

Comments

Albert ARIBAUD - Oct. 10, 2018, 12:12 p.m.
Now that __time_64_t exists, we can switch internal function
__tz_convert from 32-bit to 64-bit time. This involves switching
some other internal functions and turning some implementations
which use these into wrappers between public 32-bit and internal
64-bit time.

This patch was tested as follows:
* running 'make check' on branch release/2.28/master
* applying the patch above branch release/2.28/master
* running 'make check' again
* checking that both 'make check' yield identical results.
The test was performed:
* on x86_64-linux-gnu
* on i686-linux-gnu.

* __tz_compute: Pass timer as a __time64_t rather than time_t.
* __offtime: Pass __timer as a __time64_t value rather than
  a const time_t pointer.
* __tz_convert: Likewise.
* localtime: provide a 64-bit time version and make the 32-bit
  time version a wrapper of it.
* localtime_r: Likewise.
* ctime: Likewise.
* ctime_r: Likewise.
* gmtime: Likewise.
* gmtime_r: Likewise.
---
 include/time.h   | 44 +++++++++++++++++++++++++++++++++++++++-----
 time/ctime.c     | 17 +++++++++++++++--
 time/ctime_r.c   | 17 +++++++++++++++--
 time/gmtime.c    | 37 +++++++++++++++++++++++++++++++++----
 time/localtime.c | 37 +++++++++++++++++++++++++++++++++----
 time/offtime.c   | 12 ++++++------
 time/tzfile.c    | 14 ++++----------
 time/tzset.c     | 27 ++++++++++-----------------
 8 files changed, 155 insertions(+), 50 deletions(-)
Joseph Myers - Oct. 10, 2018, 4:24 p.m.
On Wed, 10 Oct 2018, Albert ARIBAUD (3ADEV) wrote:

> * running 'make check' on branch release/2.28/master
> * applying the patch above branch release/2.28/master
> * running 'make check' again
> * checking that both 'make check' yield identical results.

Please don't use release branches for this testing, at all.  You're 
proposing patches for master.  You need to do the testing on master.  
Just ignore release branches completely for this work (unless it turns out 
that a patch in this series introduces a regression that gets into a 
release branch before it's discovered and fixed, in which case release 
branches become relevant for testing cherry-picks of the fix to them, 
after the fix is verified and committed on master).

Patch

diff --git a/include/time.h b/include/time.h
index e99711a556..2710b4521a 100644
--- a/include/time.h
+++ b/include/time.h
@@ -46,7 +46,7 @@  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
@@ -56,18 +56,52 @@  extern time_t __mktime_internal (struct tm *__tp,
 				 struct tm *(*__func) (const time_t *,
 						       struct tm *),
 				 long int *__offset) attribute_hidden;
+
+/* nis/nis_print.c needs ctime, so even if ctime is not declared here,
+   we define __ctime64 as ctime so that nis/nis_print.c can get linked
+   against a function called ctime. */
+#if __TIMESIZE == 64
+# define __ctime64 ctime
+#endif
+
+#if __TIMESIZE == 64
+# define __ctime64_r ctime_r
+#endif
+
+#if __TIMESIZE == 64
+# define __localtime64 localtime
+#else
+extern struct tm *__localtime64 (const __time64_t *__timer);
+libc_hidden_proto (__localtime64)
+#endif
+
 extern struct tm *__localtime_r (const time_t *__timer,
 				 struct tm *__tp) attribute_hidden;
 
+#if __TIMESIZE == 64
+# define __localtime64_r __localtime_r
+#else
+extern struct tm *__localtime64_r (const __time64_t *__timer,
+				   struct tm *__tp) attribute_hidden;
+#endif
+
 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,
+#if __TIMESIZE == 64
+# define __gmtime64 gmtime
+# define __gmtime64_r __gmtime_r
+#else
+extern struct tm *__gmtime64_r (const __time64_t *__restrict __timer,
+			        struct tm *__restrict __tp);
+#endif
+
+/* 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 (__time64_t __timer,
 		      long int __offset,
 		      struct tm *__tp) attribute_hidden;
 
@@ -76,8 +110,8 @@  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 (__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/ctime.c b/time/ctime.c
index 1222614f29..286c6b579c 100644
--- a/time/ctime.c
+++ b/time/ctime.c
@@ -20,9 +20,22 @@ 
 /* Return a string as returned by asctime which
    is the representation of *T in that form.  */
 char *
-ctime (const time_t *t)
+__ctime64 (const __time64_t *t)
 {
   /* The C Standard says ctime (t) is equivalent to asctime (localtime (t)).
      In particular, ctime and asctime must yield the same pointer.  */
-  return asctime (localtime (t));
+  return asctime (__localtime64 (t));
 }
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
+
+char *
+ctime (const time_t *t)
+{
+  __time64_t t64 = *t;
+  return __ctime64 (&t64);
+}
+
+#endif
diff --git a/time/ctime_r.c b/time/ctime_r.c
index c111146d76..84089599a7 100644
--- a/time/ctime_r.c
+++ b/time/ctime_r.c
@@ -22,8 +22,21 @@ 
 /* Return a string as returned by asctime which is the representation
    of *T in that form.  Reentrant version.  */
 char *
-ctime_r (const time_t *t, char *buf)
+__ctime64_r (const __time64_t *t, char *buf)
 {
   struct tm tm;
-  return __asctime_r (__localtime_r (t, &tm), buf);
+  return __asctime_r (__localtime64_r (t, &tm), buf);
 }
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
+
+char *
+ctime_r (const time_t *t, char *buf)
+{
+  __time64_t t64 = *t;
+  return __ctime64_r (&t64, buf);
+}
+
+#endif
diff --git a/time/gmtime.c b/time/gmtime.c
index dc33b3e68a..d485a38c6f 100644
--- a/time/gmtime.c
+++ b/time/gmtime.c
@@ -18,20 +18,49 @@ 
 
 #include <time.h>
 
-/* Return the `struct tm' representation of *T in UTC,
+/* Return the `struct tm' representation of 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
+
 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
diff --git a/time/localtime.c b/time/localtime.c
index 8684a8a971..8e3b76e6cb 100644
--- a/time/localtime.c
+++ b/time/localtime.c
@@ -21,21 +21,50 @@ 
 /* The C Standard says that localtime and gmtime return the same pointer.  */
 struct tm _tmbuf;
 
-
 /* 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_convert (*t, 1, tp);
+}
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
+
 struct tm *
 __localtime_r (const time_t *t, struct tm *tp)
 {
-  return __tz_convert (t, 1, tp);
+  __time64_t t64 = *t;
+  return __localtime64_r (&t64, tp);
 }
-weak_alias (__localtime_r, localtime_r)
 
+#endif
+
+/* This always works because either __TIMESIZE != 64 and __localtime_r
+   exists or __TIMESIZE == 64 and the definition of __localtime64_r above
+   actually defined __localtime_r.  */
+weak_alias (__localtime_r, localtime_r)
 
 /* Return the `struct tm' representation of *T in local time.  */
+struct tm *
+__localtime64 (const __time64_t *t)
+{
+  return __tz_convert (*t, 1, &_tmbuf);
+}
+libc_hidden_def (__localtime64)
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
+
 struct tm *
 localtime (const time_t *t)
 {
-  return __tz_convert (t, 1, &_tmbuf);
+  __time64_t t64 = *t;
+  return __localtime64 (&t64);
 }
 libc_hidden_def (localtime)
+
+#endif
diff --git a/time/offtime.c b/time/offtime.c
index 04c48389fc..3309fcd484 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 (__time64_t t, long int offset, struct tm *tp)
 {
-  time_t days, rem, y;
+  __time64_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)
     {
@@ -60,7 +60,7 @@  __offtime (const time_t *t, long int offset, struct tm *tp)
   while (days < 0 || days >= (__isleap (y) ? 366 : 365))
     {
       /* Guess a corrected year, assuming 365 days per year.  */
-      time_t yg = y + days / 365 - (days % 365 < 0);
+      __time64_t yg = y + days / 365 - (days % 365 < 0);
 
       /* Adjust DAYS and Y to match the guessed year.  */
       days -= ((yg - y) * 365
diff --git a/time/tzfile.c b/time/tzfile.c
index 844a68de8c..3920525bf3 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -633,16 +633,10 @@  __tzfile_compute (__time64_t timer, int use_localtime,
 
 	  /* Convert to broken down structure.  If this fails do not
 	     use the string.  */
-	  {
-	    time_t truncated = timer;
-	    if (__glibc_unlikely (truncated != timer
-				  || ! __offtime (&truncated, 0, tp)))
-	      goto use_last;
-	  }
-
-	  /* Use the rules from the TZ string to compute the change.
-	     timer fits into time_t due to the truncation check
-	     above.  */
+	  if (__glibc_unlikely (! __offtime (timer, 0, tp)))
+	    goto use_last;
+
+	  /* Use the rules from the TZ string to compute the change.  */
 	  __tz_compute (timer, tp, 1);
 
 	  /* If tzspec comes from posixrules loaded by __tzfile_default,
diff --git a/time/tzset.c b/time/tzset.c
index a828b9fb75..834cc3ccec 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>
@@ -27,7 +26,7 @@ 
 
 #include <timezone/tzfile.h>
 
-#define SECSPERDAY ((time_t) 86400)
+#define SECSPERDAY ((__time64_t) 86400)
 
 char *__tzname[2] = { (char *) "GMT", (char *) "GMT" };
 int __daylight = 0;
@@ -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 = -1;
       update_vars ();
       return;
     }
@@ -424,13 +423,13 @@  tzset_internal (int always)
   __tzset_parse_tz (tz);
 }
 
-/* Figure out the exact time (as a time_t) in YEAR
+/* Figure out the exact time (as a __time64_t) in YEAR
    when the change described by RULE will occur and
    put it in RULE->change, saving YEAR in RULE->computed_for.  */
 static void
 compute_change (tz_rule *rule, int year)
 {
-  time_t t;
+  __time64_t t;
 
   if (year != -1 && rule->computed_for == year)
     /* Operations on times in 2 BC will be slower.  Oh well.  */
@@ -516,7 +515,7 @@  compute_change (tz_rule *rule, int year)
 /* Figure out the correct timezone for TM and set `__tzname',
    `__timezone', and `__daylight' accordingly.  */
 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 +561,14 @@  __tzset (void)
 }
 weak_alias (__tzset, tzset)
 
-/* 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 (__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 +577,14 @@  __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;
     }