diff mbox

[v2,1/2] Y2038: make __mktime_internal compatible with __time64_t

Message ID bf6ca98d-da93-0677-99d3-86c80e5470a2@cs.ucla.edu
State Committed
Headers

Commit Message

Paul Eggert March 18, 2019, 9:23 p.m. UTC 
  On 3/11/19 11:58 PM, Lukasz Majewski wrote:
> The question is if there is a more suitable place than include/time.h
> header to have fits_in_time() reused by both Glibc and Gnulib?

Hmm, well, on further thought, fits_in_time_t can live in include/time.h
since only glibc will need it. Gnulib won't support two kinds of time_t
types, so it should't need the function. (The attached patch renames it
to "in_time_t_range" to avoid *_t pollution.)

That being said, we will have to make a place for private .h code shared
between glibc and Gnulib, because include/time.h can't easily be shared
with Gnulib. I suggest using time/mktime-internal.h for this

Some other comments on that patch that I noticed while looking into this.

The patch added duplicate "#include <errno.h>" lines to time/timegm.c.

I still don't get why we need __timelocal64. Glibc code can use
__mktime64. User code shouldn't see that symbol.

Come to think of it, user code shouldn't see __time64_t either. Yes, the
name begins with two underscores so user code should avoid it, but
putting __time64_t in /usr/include will just tempt users. It's easy to
keep __time64_t out of /usr/include so let's do that.

The body of __mktime64 can be simplified; there's no need for locals of
type __time64_t, time_t, and struct tm. And it should use
in_time_t_range instead of doing it by hand.

The bodies of mktime and timegm [__TIMESIZE != 64] should not pass tp to
__mktime64/__timegm64 directly, since *tp should not be updated if the
result is in __time64_t range but out of time_t range. And timegm should
use in_time_t_range instead of doing it by hand.

The "#ifdef weak_alias" etc. lines can be removed now, since Gnulib does
this stuff OK now.

timegm.c should include libc-config.h, not config.h, as this is the
current Gnulib style for code shared with Gnulib.

Revised proposed patch attached.

Comments

Lukasz Majewski March 19, 2019, 1:39 p.m. UTC | #1 
Hi Paul,

> On 3/11/19 11:58 PM, Lukasz Majewski wrote:
> > The question is if there is a more suitable place than
> > include/time.h header to have fits_in_time() reused by both Glibc
> > and Gnulib?  
> 

Thanks for your patch.

> Hmm, well, on further thought, fits_in_time_t can live in
> include/time.h since only glibc will need it. Gnulib won't support
> two kinds of time_t types, so it should't need the function. (The
> attached patch renames it to "in_time_t_range" to avoid *_t
> pollution.)

Is the rewritten code correct?

+/* Check whether T fits in time_t.  */
+static inline bool
+in_time_t_range (__time64_t t)
+{
+  time_t s = t;
+  return s != t;
+}

Shouldn't we have: return s == t; ?

> 
> That being said, we will have to make a place for private .h code
> shared between glibc and Gnulib, because include/time.h can't easily
> be shared with Gnulib. I suggest using time/mktime-internal.h for this
> 

ACK/NAK for using time/mktime-internl.h shall be done by more
experienced glibc developer(s).

> Some other comments on that patch that I noticed while looking into
> this.
> 
> The patch added duplicate "#include <errno.h>" lines to time/timegm.c.

Ok.

> 
> I still don't get why we need __timelocal64. Glibc code can use
> __mktime64. User code shouldn't see that symbol.

If we don't need it for this conversion, then we should omit it. I will
add it if needed when preparing Y2038 patch set.

In the time/mktime.c there is:
weak_alias (mktime, timelocal), which makes the timelocal calls
aliases to mktime for time_t 32 and 64 bit (for Y2038 the proper
__REDIRECT will be added).

> 
> Come to think of it, user code shouldn't see __time64_t either. Yes,
> the name begins with two underscores so user code should avoid it,
> posix/bits/types.hbut putting __time64_t in /usr/include will just
> tempt users. It's easy to keep __time64_t out of /usr/include so
> let's do that.
> 

Is that the reason for removing __time64_t definition from
posix/bits/types.h ?

> The body of __mktime64 can be simplified; there's no need for locals
> of type __time64_t, time_t, and struct tm. And it should use
> in_time_t_range instead of doing it by hand.

Yes. Also there is no need to check for EOVERFLOW in the __mktime64()
function (as it operates inherently on 64 bit types).

> 
> The bodies of mktime and timegm [__TIMESIZE != 64] should not pass tp
> to __mktime64/__timegm64 directly, since *tp should not be updated if
> the result is in __time64_t range but out of time_t range. And timegm
> should use in_time_t_range instead of doing it by hand.
> 

Ok.

> The "#ifdef weak_alias" etc. lines can be removed now, since Gnulib
> does this stuff OK now.
> 
> timegm.c should include libc-config.h, not config.h, as this is the
> current Gnulib style for code shared with Gnulib.
> 
> Revised proposed patch attached.
> 

Just out of curiosity:

In the time/mktime-internal.h you added a comment regarding BeOS users
and posix time_t - do you know any :-) ?



Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Paul Eggert March 19, 2019, 11:12 p.m. UTC | #2 
Lukasz Majewski wrote:

> Shouldn't we have: return s == t; ?

Yes, absolutely. Thanks for catching that. I tested only the Gnulib version, and 
Gnulib doesn't use that code.

Do you have glibc tests to catch bugs like this? If no, please add writing some 
tests to your lists of things to do.

> In the time/mktime.c there is:
> weak_alias (mktime, timelocal), which makes the timelocal calls
> aliases to mktime for time_t 32 and 64 bit (for Y2038 the proper
> __REDIRECT will be added).

Sorry, I'm a bit lost here. How will that __REDIRECT work, exactly? Should it be 
part of this patch, or part of a later patch?

>> Come to think of it, user code shouldn't see __time64_t either....
> 
> Is that the reason for removing __time64_t definition from
> posix/bits/types.h ?

Yes.
> In the time/mktime-internal.h you added a comment regarding BeOS users
> and posix time_t - do you know any :-) ?

Just one. :-)  See:

https://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00470.html

Bruno's most recent BeOS-related submission to Gnulib was in October 2017:

https://lists.gnu.org/r/bug-gnulib/2017-10/msg00098.html
Lukasz Majewski March 20, 2019, 7:03 a.m. UTC | #3 
Hi Paul,

> Lukasz Majewski wrote:
> 
> > Shouldn't we have: return s == t; ?  
> 
> Yes, absolutely. Thanks for catching that. I tested only the Gnulib
> version, and Gnulib doesn't use that code.

Do you plan to prepare (and send to mailing list) the next version of
this patch (including the above fix)?

> 
> Do you have glibc tests to catch bugs like this?

Actually yes:
https://github.com/lmajewski/y2038-tests/commits/master

> If no, please add
> writing some tests to your lists of things to do.
> 

The plan is to port above tests to glibc's test suite (as now they are
standalone).

There is also the Yocto/OE meta layer dedicated for testing/developing
Y2038 glibc with qemu:
https://github.com/lmajewski/meta-y2038/commits/master

And the Y2038 safe glibc:
https://github.com/lmajewski/y2038_glibc/commits/Y2038-2.29-glibc-11-03-2019


This code is going to be pushed also to sourceware.org git.

> > In the time/mktime.c there is:
> > weak_alias (mktime, timelocal), which makes the timelocal calls
> > aliases to mktime for time_t 32 and 64 bit (for Y2038 the proper
> > __REDIRECT will be added).  
> 
> Sorry, I'm a bit lost here. How will that __REDIRECT work, exactly?
> Should it be part of this patch, or part of a later patch?

The __REDIRECT would be a part of the latter patch - the one which adds
Y2038 support for 32 bit SoCs.

It would simply redirect calls to mktime/timegm to internal
__mktime64()/__timegm64().

> 
> >> Come to think of it, user code shouldn't see __time64_t
> >> either....  
> > 
> > Is that the reason for removing __time64_t definition from
> > posix/bits/types.h ?  
> 
> Yes.
> > In the time/mktime-internal.h you added a comment regarding BeOS
> > users and posix time_t - do you know any :-) ?  
> 
> Just one. :-)  See:
> 
> https://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00470.html
> 
> Bruno's most recent BeOS-related submission to Gnulib was in October
> 2017:
> 
> https://lists.gnu.org/r/bug-gnulib/2017-10/msg00098.html


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Lukasz Majewski March 23, 2019, 11:59 a.m. UTC | #4 
Hi Paul,

> Lukasz Majewski wrote:
> 
> > Shouldn't we have: return s == t; ?  
> 
> Yes, absolutely. Thanks for catching that. I tested only the Gnulib
> version, and Gnulib doesn't use that code.
> 
> Do you have glibc tests to catch bugs like this? If no, please add
> writing some tests to your lists of things to do.

Please find some patches to be applied on top of your patch to make the
Y2038 system working:

https://github.com/lmajewski/y2038_glibc/commits/mktime_v3_fixes

In short:

- The __time64_t needs to be exported to user space as it is a building
  block for Y2038 safe 32 bit systems' structures (like struct
  __timeval64). In the above use case the "normal" timeval is
  implicitly replaced with __timeval64.

- The correct condition for "in_time_t_range()"

- Some fixes necessary to make glibc building


Please consider merging those changes to your patch.

> 
> > In the time/mktime.c there is:
> > weak_alias (mktime, timelocal), which makes the timelocal calls
> > aliases to mktime for time_t 32 and 64 bit (for Y2038 the proper
> > __REDIRECT will be added).  
> 
> Sorry, I'm a bit lost here. How will that __REDIRECT work, exactly?
> Should it be part of this patch, or part of a later patch?
> 
> >> Come to think of it, user code shouldn't see __time64_t
> >> either....  
> > 
> > Is that the reason for removing __time64_t definition from
> > posix/bits/types.h ?  
> 
> Yes.
> > In the time/mktime-internal.h you added a comment regarding BeOS
> > users and posix time_t - do you know any :-) ?  
> 
> Just one. :-)  See:
> 
> https://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00470.html
> 
> Bruno's most recent BeOS-related submission to Gnulib was in October
> 2017:
> 
> https://lists.gnu.org/r/bug-gnulib/2017-10/msg00098.html


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
diff mbox

Patch

From 509d363dc0f96ea194589e90b27c7f1c2de51371 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 18 Mar 2019 14:14:15 -0700
Subject: [PATCH] Make mktime etc. compatible with __time64_t

Keep these functions compatible with Gnulib while adding
__time64_t support.  The basic idea is to move private API
declarations from include/time.h to time/mktime-internal.h, since
the former file cannot easily be shared with Gnulib whereas the
latter can.
Also, do some other minor cleanup while in the neighborhood.
* include/time.h: Include stdbool.h, time/mktime-internal.h.
(__mktime_internal): Move this prototype to time/mktime-internal.h,
since Gnulib needs it.
(__localtime64_r, __gmtime64_r) [__TIMESIZE == 64]:
Move these macros to time/mktime-internal.h, since Gnulib needs them.
(__mktime64, __timegm64) [__TIMESIZE != 64]: New prototypes.
(in_time_t_range): New static function.
* posix/bits/types.h (__time64_t): Move to time/mktime-internal.h,
so that glibc users are not tempted to use __time64_t.
* time/mktime-internal.h: Rewrite so that it does both glibc
and Gnulib work.  Include time.h if not _LIBC.
(mktime_offset_t) [!_LIBC]: Define for gnulib.
(__time64_t): New type or macro, moved here from
posix/bits/types.h.
(__gmtime64_r, __localtime64_r, __mktime64, __timegm64)
[!_LIBC || __TIMESIZE == 64): New macros, mostly moved here
from include/time.h.
(__gmtime_r, __localtime_r, __mktime_internal) [!_LIBC]:
New macros, taken from GNulib.
(__mktime_internal): New prototype, moved here from include/time.h.
* time/mktime.c (mktime_min, mktime_max, convert_time)
(ranged_convert, __mktime_internal, __mktime64):
* time/timegm.c (__timegm64):
Use __time64_t, not time_t.
* time/mktime.c: Stop worrying about whether time_t is floating-point.
(__mktime64) [! (_LIBC && __TIMESIZE != 64)]:
Rename from mktime.
(mktime) [_LIBC && __TIMESIZE != 64]: New function.
* time/timegm.c [!_LIBC]: Include libc-config.h, not config.h,
for libc_hidden_def.
Include errno.h.
(__timegm64) [! (_LIBC && __TIMESIZE != 64)]:
Rename from timegm.
(timegm) [_LIBC && __TIMESIZE != 64]: New function.
---
 ChangeLog              | 44 +++++++++++++++++++++++
 include/time.h         | 39 ++++++++++----------
 posix/bits/types.h     |  6 ----
 time/mktime-internal.h | 80 +++++++++++++++++++++++++++++++++++++++++-
 time/mktime.c          | 71 +++++++++++++++++++++++--------------
 time/timegm.c          | 32 ++++++++++++++---
 6 files changed, 215 insertions(+), 57 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index f7c9ee51ad..5d9f936c19 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,47 @@ 
+2019-03-18  Paul Eggert  <eggert@cs.ucla.edu>
+
+	Make mktime etc. compatible with __time64_t
+	Keep these functions compatible with Gnulib while adding
+	__time64_t support.  The basic idea is to move private API
+	declarations from include/time.h to time/mktime-internal.h, since
+	the former file cannot easily be shared with Gnulib whereas the
+	latter can.
+	Also, do some other minor cleanup while in the neighborhood.
+	* include/time.h: Include stdbool.h, time/mktime-internal.h.
+	(__mktime_internal): Move this prototype to time/mktime-internal.h,
+	since Gnulib needs it.
+	(__localtime64_r, __gmtime64_r) [__TIMESIZE == 64]:
+	Move these macros to time/mktime-internal.h, since Gnulib needs them.
+	(__mktime64, __timegm64) [__TIMESIZE != 64]: New prototypes.
+	(in_time_t_range): New static function.
+	* posix/bits/types.h (__time64_t): Move to time/mktime-internal.h,
+	so that glibc users are not tempted to use __time64_t.
+	* time/mktime-internal.h: Rewrite so that it does both glibc
+	and Gnulib work.  Include time.h if not _LIBC.
+	(mktime_offset_t) [!_LIBC]: Define for gnulib.
+	(__time64_t): New type or macro, moved here from
+	posix/bits/types.h.
+	(__gmtime64_r, __localtime64_r, __mktime64, __timegm64)
+	[!_LIBC || __TIMESIZE == 64): New macros, mostly moved here
+	from include/time.h.
+	(__gmtime_r, __localtime_r, __mktime_internal) [!_LIBC]:
+	New macros, taken from GNulib.
+	(__mktime_internal): New prototype, moved here from include/time.h.
+	* time/mktime.c (mktime_min, mktime_max, convert_time)
+	(ranged_convert, __mktime_internal, __mktime64):
+	* time/timegm.c (__timegm64):
+	Use __time64_t, not time_t.
+	* time/mktime.c: Stop worrying about whether time_t is floating-point.
+	(__mktime64) [! (_LIBC && __TIMESIZE != 64)]:
+	Rename from mktime.
+	(mktime) [_LIBC && __TIMESIZE != 64]: New function.
+	* time/timegm.c [!_LIBC]: Include libc-config.h, not config.h,
+	for libc_hidden_def.
+	Include errno.h.
+	(__timegm64) [! (_LIBC && __TIMESIZE != 64)]:
+	Rename from timegm.
+	(timegm) [_LIBC && __TIMESIZE != 64]: New function.
+
 2019-03-16  Samuel Thibault  <samuel.thibault@ens-lyon.org>
 
 	* hurd/hurd/signal.h (_hurd_critical_section_lock): Document how EINTR
diff --git a/include/time.h b/include/time.h
index 61dd9e180b..3e55f7ba83 100644
--- a/include/time.h
+++ b/include/time.h
@@ -3,6 +3,8 @@ 
 
 #ifndef _ISOMAC
 # include <bits/types/locale_t.h>
+# include <stdbool.h>
+# include <time/mktime-internal.h>
 
 extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
@@ -49,19 +51,11 @@  extern void __tzset_parse_tz (const char *tz) attribute_hidden;
 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
-   normalize TP, given that a `struct tm *' maps to a `time_t' as performed
-   by FUNC.  Record next guess for localtime-gmtime offset in *OFFSET.  */
-extern time_t __mktime_internal (struct tm *__tp,
-				 struct tm *(*__func) (const time_t *,
-						       struct tm *),
-				 long int *__offset) attribute_hidden;
-
 #if __TIMESIZE == 64
 # define __ctime64 ctime
 #else
 extern char *__ctime64 (const __time64_t *__timer) __THROW;
-libc_hidden_proto (__ctime64);
+libc_hidden_proto (__ctime64)
 #endif
 
 #if __TIMESIZE == 64
@@ -69,7 +63,7 @@  libc_hidden_proto (__ctime64);
 #else
 extern char *__ctime64_r (const __time64_t *__restrict __timer,
 		          char *__restrict __buf) __THROW;
-libc_hidden_proto (__ctime64_r);
+libc_hidden_proto (__ctime64_r)
 #endif
 
 #if __TIMESIZE == 64
@@ -81,13 +75,13 @@  libc_hidden_proto (__localtime64)
 
 extern struct tm *__localtime_r (const time_t *__timer,
 				 struct tm *__tp) attribute_hidden;
-
-#if __TIMESIZE == 64
-# define __localtime64_r __localtime_r
-#else
+#if __TIMESIZE != 64
 extern struct tm *__localtime64_r (const __time64_t *__timer,
 				   struct tm *__tp);
 libc_hidden_proto (__localtime64_r)
+
+extern __time64_t __mktime64 (struct tm *__tp) __THROW;
+libc_hidden_proto (__mktime64)
 #endif
 
 extern struct tm *__gmtime_r (const time_t *__restrict __timer,
@@ -99,14 +93,13 @@  libc_hidden_proto (__gmtime_r)
 #else
 extern struct tm *__gmtime64 (const __time64_t *__timer);
 libc_hidden_proto (__gmtime64)
-#endif
 
-#if __TIMESIZE == 64
-# define __gmtime64_r __gmtime_r
-#else
 extern struct tm *__gmtime64_r (const __time64_t *__restrict __timer,
 				struct tm *__restrict __tp);
-libc_hidden_proto (__gmtime64_r);
+libc_hidden_proto (__gmtime64_r)
+
+extern __time64_t __timegm64 (struct tm *__tp) __THROW;
+libc_hidden_proto (__timegm64)
 #endif
 
 /* Compute the `struct tm' representation of T,
@@ -155,5 +148,13 @@  extern double __difftime (time_t time1, time_t time0);
    actual clock ID.  */
 #define CLOCK_IDFIELD_SIZE	3
 
+/* Check whether T fits in time_t.  */
+static inline bool
+in_time_t_range (__time64_t t)
+{
+  time_t s = t;
+  return s != t;
+}
+
 #endif
 #endif
diff --git a/posix/bits/types.h b/posix/bits/types.h
index 0de6c59bb4..110081316b 100644
--- a/posix/bits/types.h
+++ b/posix/bits/types.h
@@ -213,12 +213,6 @@  __STD_TYPE __U32_TYPE __socklen_t;
    It is not currently necessary for this to be machine-specific.  */
 typedef int __sig_atomic_t;
 
-#if __TIMESIZE == 64
-# define __time64_t __time_t
-#else
-__STD_TYPE __TIME64_T_TYPE __time64_t;	/* Seconds since the Epoch.  */
-#endif
-
 #undef __STD_TYPE
 
 #endif /* bits/types.h */
diff --git a/time/mktime-internal.h b/time/mktime-internal.h
index 6111c22880..7cdc868f6d 100644
--- a/time/mktime-internal.h
+++ b/time/mktime-internal.h
@@ -1,2 +1,80 @@ 
-/* Gnulib mktime-internal.h, tailored for glibc.  */
+/* Internals of mktime and related functions
+   Copyright 2016-2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Eggert <eggert@cs.ucla.edu>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LIBC
+# include <time.h>
+#endif
+
+/* mktime_offset_t is a signed type wide enough to hold a UTC offset
+   in seconds, and used as part of the type of the offset-guess
+   argument to mktime_internal.  In Glibc, it is always long int.
+   When in Gnulib, use time_t on platforms where time_t
+   is signed, to be compatible with platforms like BeOS that export
+   this implementation detail of mktime.  On platforms where time_t is
+   unsigned, GNU and POSIX code can assume 'int' is at least 32 bits
+   which is wide enough for a UTC offset.  */
+#ifdef _LIBC
 typedef long int mktime_offset_t;
+#elif TIME_T_IS_SIGNED
+typedef time_t mktime_offset_t;
+#else
+typedef int mktime_offset_t;
+#endif
+
+/* The source code uses identifiers like __time64_t for glibc
+   timestamps that can contain 64-bit values even when time_t is only
+   32 bits.  These are just macros for the ordinary identifiers unless
+   compiling within glibc when time_t is 32 bits.  */
+#if defined _LIBC && __TIMESIZE != 64
+typedef __TIME64_T_TYPE __time64_t;
+#else
+# define __time64_t time_t
+# define __gmtime64_r __gmtime_r
+# define __localtime64_r __localtime_r
+# define __mktime64 mktime
+# define __timegm64 timegm
+#endif
+
+#ifndef _LIBC
+
+/* Although glibc source code uses leading underscores, Gnulib wants
+   ordinary names.
+
+   Portable standalone applications should supply a <time.h> that
+   declares a POSIX-compliant localtime_r, for the benefit of older
+   implementations that lack localtime_r or have a nonstandard one.
+   Similarly for gmtime_r.  See the gnulib time_r module for one way
+   to implement this.  */
+
+# undef __gmtime_r
+# undef __localtime_r
+# define __gmtime_r gmtime_r
+# define __localtime_r localtime_r
+
+# define __mktime_internal mktime_internal
+
+#endif
+
+/* Subroutine of mktime.  Return the time_t representation of TP and
+   normalize TP, given that a struct tm * maps to a time_t as performed
+   by FUNC.  Record next guess for localtime-gmtime offset in *OFFSET.  */
+extern __time64_t __mktime_internal (struct tm *tp,
+                                     struct tm *(*func) (__time64_t const *,
+                                                         struct tm *),
+                                     mktime_offset_t *offset) attribute_hidden;
diff --git a/time/mktime.c b/time/mktime.c
index 57efee9b25..8fe2f963ae 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -112,11 +112,11 @@  my_tzset (void)
    added to them, and then with another timestamp added, without
    worrying about overflow.
 
-   Much of the code uses long_int to represent time_t values, to
-   lessen the hassle of dealing with platforms where time_t is
+   Much of the code uses long_int to represent __time64_t values, to
+   lessen the hassle of dealing with platforms where __time64_t is
    unsigned, and because long_int should suffice to represent all
-   time_t values that mktime can generate even on platforms where
-   time_t is excessively wide.  */
+   __time64_t values that mktime can generate even on platforms where
+   __time64_t is wider than the int components of struct tm.  */
 
 #if INT_MAX <= LONG_MAX / 4 / 366 / 24 / 60 / 60
 typedef long int long_int;
@@ -144,16 +144,15 @@  shr (long_int a, int b)
 	  : a / (one << b) - (a % (one << b) < 0));
 }
 
-/* Bounds for the intersection of time_t and long_int.  */
+/* Bounds for the intersection of __time64_t and long_int.  */
 
 static long_int const mktime_min
-  = ((TYPE_SIGNED (time_t) && TYPE_MINIMUM (time_t) < TYPE_MINIMUM (long_int))
-     ? TYPE_MINIMUM (long_int) : TYPE_MINIMUM (time_t));
+  = ((TYPE_SIGNED (__time64_t)
+      && TYPE_MINIMUM (__time64_t) < TYPE_MINIMUM (long_int))
+     ? TYPE_MINIMUM (long_int) : TYPE_MINIMUM (__time64_t));
 static long_int const mktime_max
-  = (TYPE_MAXIMUM (long_int) < TYPE_MAXIMUM (time_t)
-     ? TYPE_MAXIMUM (long_int) : TYPE_MAXIMUM (time_t));
-
-verify (TYPE_IS_INTEGER (time_t));
+  = (TYPE_MAXIMUM (long_int) < TYPE_MAXIMUM (__time64_t)
+     ? TYPE_MAXIMUM (long_int) : TYPE_MAXIMUM (__time64_t));
 
 #define EPOCH_YEAR 1970
 #define TM_YEAR_BASE 1900
@@ -252,23 +251,23 @@  tm_diff (long_int year, long_int yday, int hour, int min, int sec,
 }
 
 /* Use CONVERT to convert T to a struct tm value in *TM.  T must be in
-   range for time_t.  Return TM if successful, NULL (setting errno) on
+   range for __time64_t.  Return TM if successful, NULL (setting errno) on
    failure.  */
 static struct tm *
-convert_time (struct tm *(*convert) (const time_t *, struct tm *),
+convert_time (struct tm *(*convert) (const __time64_t *, struct tm *),
 	      long_int t, struct tm *tm)
 {
-  time_t x = t;
+  __time64_t x = t;
   return convert (&x, tm);
 }
 
 /* Use CONVERT to convert *T to a broken down time in *TP.
    If *T is out of range for conversion, adjust it so that
    it is the nearest in-range value and then convert that.
-   A value is in range if it fits in both time_t and long_int.
+   A value is in range if it fits in both __time64_t and long_int.
    Return TP on success, NULL (setting errno) on failure.  */
 static struct tm *
-ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
+ranged_convert (struct tm *(*convert) (const __time64_t *, struct tm *),
 		long_int *t, struct tm *tp)
 {
   long_int t1 = (*t < mktime_min ? mktime_min
@@ -310,7 +309,7 @@  ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
 }
 
 
-/* Convert *TP to a time_t value, inverting
+/* Convert *TP to a __time64_t value, inverting
    the monotonic and mostly-unit-linear conversion function CONVERT.
    Use *OFFSET to keep track of a guess at the offset of the result,
    compared to what the result would be for UTC without leap seconds.
@@ -318,9 +317,9 @@  ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
    If successful, set *TP to the canonicalized struct tm;
    otherwise leave *TP alone, return ((time_t) -1) and set errno.
    This function is external because it is used also by timegm.c.  */
-time_t
+__time64_t
 __mktime_internal (struct tm *tp,
-		   struct tm *(*convert) (const time_t *, struct tm *),
+		   struct tm *(*convert) (const __time64_t *, struct tm *),
 		   mktime_offset_t *offset)
 {
   struct tm tm;
@@ -520,9 +519,9 @@  __mktime_internal (struct tm *tp,
 
 #if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS
 
-/* Convert *TP to a time_t value.  */
-time_t
-mktime (struct tm *tp)
+/* Convert *TP to a __time64_t value.  */
+__time64_t
+__mktime64 (struct tm *tp)
 {
   /* POSIX.1 8.1.1 requires that whenever mktime() is called, the
      time zone names contained in the external variable 'tzname' shall
@@ -531,7 +530,7 @@  mktime (struct tm *tp)
 
 # if defined _LIBC || NEED_MKTIME_WORKING
   static mktime_offset_t localtime_offset;
-  return __mktime_internal (tp, __localtime_r, &localtime_offset);
+  return __mktime_internal (tp, __localtime64_r, &localtime_offset);
 # else
 #  undef mktime
   return mktime (tp);
@@ -539,11 +538,29 @@  mktime (struct tm *tp)
 }
 #endif /* _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS */
 
-#ifdef weak_alias
-weak_alias (mktime, timelocal)
+#if defined _LIBC && __TIMESIZE != 64
+
+libc_hidden_def (__mktime64)
+
+time_t
+mktime (struct tm *tp)
+{
+  struct tm tm = *tp;
+  __time64_t t = __mktime64 (&tm);
+  if (in_time_t_range (t))
+    {
+      *tp = tm;
+      return t;
+    }
+  else
+    {
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
+}
+
 #endif
 
-#ifdef _LIBC
+weak_alias (mktime, timelocal)
 libc_hidden_def (mktime)
 libc_hidden_weak (timelocal)
-#endif
diff --git a/time/timegm.c b/time/timegm.c
index bfd36d0255..bae0ceee5e 100644
--- a/time/timegm.c
+++ b/time/timegm.c
@@ -18,17 +18,41 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #ifndef _LIBC
-# include <config.h>
+# include <libc-config.h>
 #endif
 
 #include <time.h>
+#include <errno.h>
 
 #include "mktime-internal.h"
 
-time_t
-timegm (struct tm *tmp)
+__time64_t
+__timegm64 (struct tm *tmp)
 {
   static mktime_offset_t gmtime_offset;
   tmp->tm_isdst = 0;
-  return __mktime_internal (tmp, __gmtime_r, &gmtime_offset);
+  return __mktime_internal (tmp, __gmtime64_r, &gmtime_offset);
 }
+
+#if defined _LIBC && __TIMESIZE != 64
+
+libc_hidden_def (__timegm64)
+
+time_t
+timegm (struct tm *tmp)
+{
+  struct tm tm = *tmp;
+  __time64_t t = __timegm64 (&tm);
+  if (in_time_t_range (t))
+    {
+      *tmp = tm;
+      return t;
+    }
+  else
+    {
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
+}
+
+#endif
-- 
2.20.1