mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 12:41:05 +00:00
78274dc8ce
Bug 22639 reports localtime failing to handle time offset transitions
correctly in 2039 and later on platforms with 64-bit time_t.
The problem is the use of SECSPERDAY (constant 86400) in calculations
such as
t = ((year - 1970) * 365
+ /* Compute the number of leapdays between 1970 and YEAR
(exclusive). There is a leapday every 4th year ... */
+ ((year - 1) / 4 - 1970 / 4)
/* ... except every 100th year ... */
- ((year - 1) / 100 - 1970 / 100)
/* ... but still every 400th year. */
+ ((year - 1) / 400 - 1970 / 400)) * SECSPERDAY;
where t is of type time_t and year is of type int. Before my commit
92bd70fb85 (an update from tzcode,
included in 2.26 and later releases), SECSPERDAY was obtained from a
file imported from tzcode, where the value included a cast to
int_fast32_t. On 64-bit platforms, glibc defines int_fast32_t to be
long int, so 64-bit, but my patch resulted in it changing to int.
(The bug would probably have existed even before my patch for x32,
which has 64-bit time_t but 32-bit int_fast32_t, but I haven't
verified that.)
This patch fixes the problem by including a cast to time_t in the
definition of SECSPERDAY. (64-bit time support for 32-bit systems
should move such code that isn't a public interface to using the
internal 64-bit version of time_t throughout.)
Tested for x86_64 and x86.
[BZ #22639]
* time/tzset.c (SECSPERDAY): Cast to time_t.
* time/tst-y2039.c: New file.
* time/Makefile (tests): Add tst-y2039.
47 lines
1.5 KiB
C
47 lines
1.5 KiB
C
/* Test for localtime bug in year 2039 (bug 22639).
|
|
Copyright (C) 2017-2018 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
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
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <time.h>
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <support/check.h>
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
TEST_VERIFY_EXIT (setenv ("TZ", "PST8PDT,M3.2.0,M11.1.0", 1) == 0);
|
|
tzset ();
|
|
if (sizeof (time_t) > 4)
|
|
{
|
|
time_t ouch = (time_t) 2187810000LL;
|
|
char buf[500];
|
|
struct tm *tm = localtime (&ouch);
|
|
TEST_VERIFY_EXIT (tm != NULL);
|
|
TEST_VERIFY_EXIT (strftime (buf, sizeof buf, "%Y-%m-%d %H:%M:%S %Z", tm)
|
|
> 0);
|
|
puts (buf);
|
|
TEST_VERIFY (strcmp (buf, "2039-04-30 14:00:00 PDT") == 0);
|
|
}
|
|
else
|
|
FAIL_UNSUPPORTED ("32-bit time_t");
|
|
return 0;
|
|
}
|
|
|
|
#include <support/test-driver.c>
|