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Commit 90b6ce9c authored by pang.xunlei's avatar pang.xunlei Committed by John Stultz
Browse files

time: Provide y2038 safe mktime() replacement 



As part of addressing "y2038 problem" for in-kernel uses, this
patch adds safe mktime64() using time64_t.

After this patch, mktime() is deprecated and all its call sites
will be fixed using mktime64(), after that it can be removed.

Signed-off-by: default avatarpang.xunlei <pang.xunlei@linaro.org>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 04d90890

include/linux/time.h

+14 −3
Original line number Diff line number Diff line
@@ -39,10 +39,21 @@ static inline int timeval_compare(const struct timeval *lhs, const struct timeva 
	return lhs->tv_usec - rhs->tv_usec;

}



extern unsigned long mktime(const unsigned int year, const unsigned int mon,

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);



/**

 * Deprecated. Use mktime64().

 */

static inline 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)

{

	return mktime64(year, mon, day, hour, min, sec);

}



extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);



/*

kernel/time/time.c

+8 −12
Original line number Diff line number Diff line
@@ -304,7 +304,9 @@ 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.

/*

 * mktime64 - Converts date to seconds.

 * 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.

 *
@@ -314,13 +316,8 @@ EXPORT_SYMBOL(timespec_trunc); 
 * -year/100+year/400 terms, and add 10.]

 *

 * This algorithm was first published by Gauss (I think).

 *

 * 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)

 */

unsigned long

mktime(const unsigned int year0, const unsigned int mon0,

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)

{
@@ -332,15 +329,14 @@ mktime(const unsigned int year0, const unsigned int mon0, 
		year -= 1;

	}



	return ((((unsigned long)

	return ((((time64_t)

		  (year/4 - year/100 + year/400 + 367*mon/12 + day) +

		  year*365 - 719499

	    )*24 + hour /* now have hours */

	  )*60 + min /* now have minutes */

	)*60 + sec; /* finally seconds */

}



EXPORT_SYMBOL(mktime);

EXPORT_SYMBOL(mktime64);



/**

 * set_normalized_timespec - set timespec sec and nsec parts and normalize