Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759326AbaJ3LRA (ORCPT ); Thu, 30 Oct 2014 07:17:00 -0400 Received: from mail-pd0-f175.google.com ([209.85.192.175]:55742 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759304AbaJ3LQ6 (ORCPT ); Thu, 30 Oct 2014 07:16:58 -0400 From: "pang.xunlei" To: linux-kernel@vger.kernel.org Cc: rtc-linux@googlegroups.com, xen-devel@lists.xenproject.org, John Stultz , Thomas Gleixner , Alessandro Zummo , Stefano Stabellini , "pang.xunlei" Subject: [RFC PATCH v2 02/11] time: Add mktime64() safe version(using time64_t) Date: Thu, 30 Oct 2014 19:15:36 +0800 Message-Id: <1414667745-7703-3-git-send-email-pang.xunlei@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1414667745-7703-1-git-send-email-pang.xunlei@linaro.org> References: <1414667745-7703-1-git-send-email-pang.xunlei@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As part of addressing 2038 saftey for in-kernel uses, this patch adds safe mktime64() using time64_t. After this patch, mktime() should be replaced by mktime64() one by one. Eventually, mktime() will be removed from the kernel when it has no users. Signed-off-by: pang.xunlei --- include/linux/time.h | 4 ++++ kernel/time/time.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/include/linux/time.h b/include/linux/time.h index 8c42cf8..5c2c077 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -39,6 +39,10 @@ static inline int timeval_compare(const struct timeval *lhs, const struct timeva return lhs->tv_usec - rhs->tv_usec; } +extern time64_t mktime64(const unsigned int year, const unsigned int mon, + const unsigned int day, const unsigned int hour, + const unsigned int min, const unsigned int sec); + extern unsigned long mktime(const unsigned int year, const unsigned int mon, const unsigned int day, const unsigned int hour, const unsigned int min, const unsigned int sec); diff --git a/kernel/time/time.c b/kernel/time/time.c index a9ae20f..f44efdb 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -304,6 +304,44 @@ struct timespec timespec_trunc(struct timespec t, unsigned gran) } EXPORT_SYMBOL(timespec_trunc); +/* + * Converts Gregorian date to seconds since 1970-01-01 00:00:00. + * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 + * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. + * + * [For the Julian calendar (which was used in Russia before 1917, + * Britain & colonies before 1752, anywhere else before 1582, + * and is still in use by some communities) leave out the + * -year/100+year/400 terms, and add 10.] + * + * This algorithm was first published by Gauss (I think). + * + * Safe version 2038 safety on 32-bit systems. + */ +time64_t +mktime64(const unsigned int year0, const unsigned int mon0, + const unsigned int day, const unsigned int hour, + const unsigned int min, const unsigned int sec) +{ + time64_t ret; + unsigned int mon = mon0, year = year0; + + /* 1..12 -> 11,12,1..10 */ + if (0 >= (int) (mon -= 2)) { + mon += 12; /* Puts Feb last since it has leap day */ + year -= 1; + } + + ret = (year/4 - year/100 + year/400 + 367*mon/12 + day) + year*365 - 719499; + ret = ret*24 + hour; /* now have hours */ + ret = ret*60 + min; /* now have minutes */ + ret = ret*60 + sec; /* finally seconds */ + + return ret; +} + +EXPORT_SYMBOL(mktime64); + /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. @@ -318,6 +356,7 @@ EXPORT_SYMBOL(timespec_trunc); * WARNING: this function will overflow on 2106-02-07 06:28:16 on * machines where long is 32-bit! (However, as time_t is signed, we * will already get problems at other places on 2038-01-19 03:14:08) + * TODO: [2038 safety] should be replaced by mktime64(). */ unsigned long mktime(const unsigned int year0, const unsigned int mon0, -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/