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authorJoseph Myers <joseph@codesourcery.com>2018-05-18 11:57:15 +0000
committerJoseph Myers <joseph@codesourcery.com>2018-05-18 11:57:15 +0000
commit78274dc8ceb21bb7efd8baef29e1f00031b9c1c6 (patch)
tree4312ee0c556f5057d52dad74b973a0fafa4098a8 /time/Makefile
parent6f7fdeeb69776d0d2f67fb26f92ad2807445ca5e (diff)
downloadglibc-78274dc8ceb21bb7efd8baef29e1f00031b9c1c6.tar.gz
Fix year 2039 bug for localtime with 64-bit time_t (bug 22639).
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 92bd70fb85bce57ac47ba5d8af008736832c955a (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.
Diffstat (limited to 'time/Makefile')
-rw-r--r--time/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/time/Makefile b/time/Makefile
index 0db1206820..ec3e39dcea 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -43,7 +43,7 @@ tests := test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
tst-getdate tst-mktime tst-mktime2 tst-ftime_l tst-strftime \
tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r bug-mktime1 \
tst-strptime3 bug-getdate1 tst-strptime-whitespace tst-ftime \
- tst-tzname
+ tst-tzname tst-y2039
include ../Rules