include/linux/time32.h

#ifndef _LINUX_TIME32_H
#define _LINUX_TIME32_H
/*
 * These are all interfaces based on the old time_t definition
 * that overflows in 2038 on 32-bit architectures. New code
 * should use the replacements based on time64_t and timespec64.
 *
 * Any interfaces in here that become unused as we migrate
 * code to time64_t should get removed.
 */

#include <linux/time64.h>

#define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)

#if __BITS_PER_LONG == 64

/* timespec64 is defined as timespec here */
static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
{
	return ts64;
}

static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
{
	return ts;
}

# define timespec_equal			timespec64_equal
# define timespec_compare		timespec64_compare
# define set_normalized_timespec	set_normalized_timespec64
# define timespec_add			timespec64_add
# define timespec_sub			timespec64_sub
# define timespec_valid			timespec64_valid
# define timespec_valid_strict		timespec64_valid_strict
# define timespec_to_ns			timespec64_to_ns
# define ns_to_timespec			ns_to_timespec64
# define timespec_add_ns		timespec64_add_ns

#else
static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
{
	struct timespec ret;

	ret.tv_sec = (time_t)ts64.tv_sec;
	ret.tv_nsec = ts64.tv_nsec;
	return ret;
}

static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
{
	struct timespec64 ret;

	ret.tv_sec = ts.tv_sec;
	ret.tv_nsec = ts.tv_nsec;
	return ret;
}

static inline int timespec_equal(const struct timespec *a,
				 const struct timespec *b)
{
	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
}

/*
 * lhs < rhs:  return <0
 * lhs == rhs: return 0
 * lhs > rhs:  return >0
 */
static inline int timespec_compare(const struct timespec *lhs, const struct timespec *rhs)
{
	if (lhs->tv_sec < rhs->tv_sec)
		return -1;
	if (lhs->tv_sec > rhs->tv_sec)
		return 1;
	return lhs->tv_nsec - rhs->tv_nsec;
}

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

static inline struct timespec timespec_add(struct timespec lhs,
						struct timespec rhs)
{
	struct timespec ts_delta;

	set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,
				lhs.tv_nsec + rhs.tv_nsec);
	return ts_delta;
}

/*
 * sub = lhs - rhs, in normalized form
 */
static inline struct timespec timespec_sub(struct timespec lhs,
						struct timespec rhs)
{
	struct timespec ts_delta;

	set_normalized_timespec(&ts_delta, lhs.tv_sec - rhs.tv_sec,
				lhs.tv_nsec - rhs.tv_nsec);
	return ts_delta;
}

/*
 * Returns true if the timespec is norm, false if denorm:
 */
static inline bool timespec_valid(const struct timespec *ts)
{
	/* Dates before 1970 are bogus */
	if (ts->tv_sec < 0)
		return false;
	/* Can't have more nanoseconds then a second */
	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
		return false;
	return true;
}

static inline bool timespec_valid_strict(const struct timespec *ts)
{
	if (!timespec_valid(ts))
		return false;
	/* Disallow values that could overflow ktime_t */
	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
		return false;
	return true;
}

/**
 * timespec_to_ns - Convert timespec to nanoseconds
 * @ts:		pointer to the timespec variable to be converted
 *
 * Returns the scalar nanosecond representation of the timespec
 * parameter.
 */
static inline s64 timespec_to_ns(const struct timespec *ts)
{
	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}

/**
 * ns_to_timespec - Convert nanoseconds to timespec
 * @nsec:	the nanoseconds value to be converted
 *
 * Returns the timespec representation of the nsec parameter.
 */
extern struct timespec ns_to_timespec(const s64 nsec);

/**
 * timespec_add_ns - Adds nanoseconds to a timespec
 * @a:		pointer to timespec to be incremented
 * @ns:		unsigned nanoseconds value to be added
 *
 * This must always be inlined because its used from the x86-64 vdso,
 * which cannot call other kernel functions.
 */
static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
{
	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
	a->tv_nsec = ns;
}

#endif

/**
 * time_to_tm - converts the calendar time to local broken-down time
 *
 * @totalsecs	the number of seconds elapsed since 00:00:00 on January 1, 1970,
 *		Coordinated Universal Time (UTC).
 * @offset	offset seconds adding to totalsecs.
 * @result	pointer to struct tm variable to receive broken-down time
 */
static inline void time_to_tm(time_t totalsecs, int offset, struct tm *result)
{
	time64_to_tm(totalsecs, offset, result);
}

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);
}

static inline bool timeval_valid(const struct timeval *tv)
{
	/* Dates before 1970 are bogus */
	if (tv->tv_sec < 0)
		return false;

	/* Can't have more microseconds then a second */
	if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
		return false;

	return true;
}

extern struct timespec timespec_trunc(struct timespec t, unsigned int gran);

/**
 * timeval_to_ns - Convert timeval to nanoseconds
 * @ts:		pointer to the timeval variable to be converted
 *
 * Returns the scalar nanosecond representation of the timeval
 * parameter.
 */
static inline s64 timeval_to_ns(const struct timeval *tv)
{
	return ((s64) tv->tv_sec * NSEC_PER_SEC) +
		tv->tv_usec * NSEC_PER_USEC;
}

/**
 * ns_to_timeval - Convert nanoseconds to timeval
 * @nsec:	the nanoseconds value to be converted
 *
 * Returns the timeval representation of the nsec parameter.
 */
extern struct timeval ns_to_timeval(const s64 nsec);
extern struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec);

#endif