linux_kernel/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)

typedef s32		old_time32_t;

struct old_timespec32 {
	old_time32_t	tv_sec;
	s32		tv_nsec;
};

struct old_timeval32 {
	old_time32_t	tv_sec;
	s32		tv_usec;
};

struct old_itimerspec32 {
	struct old_timespec32 it_interval;
	struct old_timespec32 it_value;
};

extern int get_old_timespec32(struct timespec64 *, const void __user *);
extern int put_old_timespec32(const struct timespec64 *, void __user *);
extern int get_old_itimerspec32(struct itimerspec64 *its,
			const struct old_itimerspec32 __user *uits);
extern int put_old_itimerspec32(const struct itimerspec64 *its,
			struct old_itimerspec32 __user *uits);


#if __BITS_PER_LONG == 64

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

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

#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;
}
#endif

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;
}

/**
 * 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;
}

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;
}

/**
 * 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);

/*
 * Old names for the 32-bit time_t interfaces, these will be removed
 * when everything uses the new names.
 */
#define compat_time_t		old_time32_t
#define compat_timeval		old_timeval32
#define compat_timespec		old_timespec32
#define compat_itimerspec	old_itimerspec32
#define ns_to_compat_timeval	ns_to_old_timeval32
#define get_compat_itimerspec64	get_old_itimerspec32
#define put_compat_itimerspec64	put_old_itimerspec32
#define compat_get_timespec64	get_old_timespec32
#define compat_put_timespec64	put_old_timespec32

#endif