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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.
77 lines
2.6 KiB
Makefile
77 lines
2.6 KiB
Makefile
# Copyright (C) 1991-2018 Free Software Foundation, Inc.
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# This file is part of the GNU C Library.
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# The GNU C Library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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# The GNU C Library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public
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# License along with the GNU C Library; if not, see
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# <http://www.gnu.org/licenses/>.
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#
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# Makefile for time routines
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#
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subdir := time
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include ../Makeconfig
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headers := time.h sys/time.h sys/timeb.h bits/time.h \
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bits/types/clockid_t.h bits/types/clock_t.h \
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bits/types/struct_itimerspec.h \
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bits/types/struct_timespec.h bits/types/struct_timeval.h \
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bits/types/struct_tm.h bits/types/timer_t.h \
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bits/types/time_t.h
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routines := offtime asctime clock ctime ctime_r difftime \
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gmtime localtime mktime time \
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gettimeofday settimeofday adjtime tzset \
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tzfile getitimer setitimer \
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stime dysize timegm ftime \
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getdate strptime strptime_l \
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strftime wcsftime strftime_l wcsftime_l \
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timespec_get
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aux := era alt_digit lc-time-cleanup
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tests := test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
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tst-getdate tst-mktime tst-mktime2 tst-ftime_l tst-strftime \
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tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r bug-mktime1 \
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tst-strptime3 bug-getdate1 tst-strptime-whitespace tst-ftime \
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tst-tzname tst-y2039
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include ../Rules
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ifeq ($(run-built-tests),yes)
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LOCALES := de_DE.ISO-8859-1 en_US.ISO-8859-1 ja_JP.EUC-JP fr_FR.UTF-8 \
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es_ES.UTF-8 pl_PL.UTF-8 ru_RU.UTF-8
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include ../gen-locales.mk
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$(objpfx)tst-ftime_l.out: $(gen-locales)
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$(objpfx)tst-strptime.out: $(gen-locales)
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endif
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tz-cflags = -DTZDIR='"$(zonedir)"' \
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-DTZDEFAULT='"$(localtime-file)"' \
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-DTZDEFRULES='"$(posixrules-file)"'
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CFLAGS-tzfile.c += $(tz-cflags)
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CFLAGS-tzset.c += $(tz-cflags)
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CFLAGS-getdate.c += -fexceptions
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# Don't warn about Y2k problem in strftime format string.
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CFLAGS-test_time.c += -Wno-format
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tst-getdate-ENV= DATEMSK=datemsk TZDIR=${common-objpfx}timezone/testdata
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test_time-ARGS= EST5EDT CST
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tst-tzname-ENV = TZDIR=${common-objpfx}timezone/testdata
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CPPFLAGS-tst-tzname.c += -DTZDEFRULES='"$(posixrules-file)"'
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bug-getdate1-ARGS = ${objpfx}bug-getdate1-fmt
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