Commit 21f7eca5 authored by pang.xunlei's avatar pang.xunlei Committed by John Stultz
Browse files

time: Provide y2038 safe do_settimeofday() replacement 



The kernel uses 32-bit signed value(time_t) for seconds elapsed
1970-01-01:00:00:00, thus it will overflow at 2038-01-19 03:14:08
on 32-bit systems. This is widely known as the y2038 problem.

As part of addressing "y2038 problem" for in-kernel uses, this patch
adds safe do_settimeofday64() using timespec64.

After this patch, do_settimeofday() is deprecated and all its call
sites will be fixed using do_settimeofday64(), 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 659bc17b

include/linux/timekeeping.h

+20 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ extern int timekeeping_suspended; 
 * Get and set timeofday

 */

extern void do_gettimeofday(struct timeval *tv);

extern int do_settimeofday(const struct timespec *tv);

extern int do_settimeofday64(const struct timespec64 *ts);

extern int do_sys_settimeofday(const struct timespec *tv,

			       const struct timezone *tz);
@@ -33,6 +33,14 @@ extern int __getnstimeofday64(struct timespec64 *tv); 
extern void getnstimeofday64(struct timespec64 *tv);



#if BITS_PER_LONG == 64

/**

 * Deprecated. Use do_settimeofday64().

 */

static inline int do_settimeofday(const struct timespec *ts)

{

	return do_settimeofday64(ts);

}



static inline int __getnstimeofday(struct timespec *ts)

{

	return __getnstimeofday64(ts);
@@ -54,6 +62,17 @@ static inline void ktime_get_real_ts(struct timespec *ts) 
}



#else

/**

 * Deprecated. Use do_settimeofday64().

 */

static inline int do_settimeofday(const struct timespec *ts)

{

	struct timespec64 ts64;



	ts64 = timespec_to_timespec64(*ts);

	return do_settimeofday64(&ts64);

}



static inline int __getnstimeofday(struct timespec *ts)

{

	struct timespec64 ts64;

kernel/time/timekeeping.c

+9 −10
Original line number Diff line number Diff line
@@ -703,18 +703,18 @@ void do_gettimeofday(struct timeval *tv) 
EXPORT_SYMBOL(do_gettimeofday);



/**

 * do_settimeofday - Sets the time of day

 * @tv:		pointer to the timespec variable containing the new time

 * do_settimeofday64 - Sets the time of day.

 * @ts:     pointer to the timespec64 variable containing the new time

 *

 * Sets the time of day to the new time and update NTP and notify hrtimers

 */

int do_settimeofday(const struct timespec *tv)

int do_settimeofday64(const struct timespec64 *ts)

{

	struct timekeeper *tk = &tk_core.timekeeper;

	struct timespec64 ts_delta, xt, tmp;

	struct timespec64 ts_delta, xt;

	unsigned long flags;



	if (!timespec_valid_strict(tv))

	if (!timespec64_valid_strict(ts))

		return -EINVAL;



	raw_spin_lock_irqsave(&timekeeper_lock, flags);
@@ -723,13 +723,12 @@ int do_settimeofday(const struct timespec *tv) 
	timekeeping_forward_now(tk);



	xt = tk_xtime(tk);

	ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;

	ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;

	ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;

	ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;



	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));



	tmp = timespec_to_timespec64(*tv);

	tk_set_xtime(tk, &tmp);

	tk_set_xtime(tk, ts);



	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
@@ -741,7 +740,7 @@ int do_settimeofday(const struct timespec *tv) 


	return 0;

}

EXPORT_SYMBOL(do_settimeofday);

EXPORT_SYMBOL(do_settimeofday64);



/**

 * timekeeping_inject_offset - Adds or subtracts from the current time.

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