root/include/linux/time.h

INCLUDED FROM

DEFINITIONS

1. timespec_equal
2. timespec_compare
3. timeval_compare
4. timespec_add
5. timespec_sub
6. timespec_valid
7. timespec_valid_strict
8. timeval_valid
9. timespec_to_ns
10. timeval_to_ns
11. timespec_add_ns

#ifndef _LINUX_TIME_H
#define _LINUX_TIME_H

# include <linux/cache.h>
# include <linux/seqlock.h>
# include <linux/math64.h>
# include <linux/time64.h>

extern struct timezone sys_tz;

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

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;
}

static inline int timeval_compare(const struct timeval *lhs, const struct timeval *rhs)
{
        if (lhs->tv_sec < rhs->tv_sec)
                return -1;
        if (lhs->tv_sec > rhs->tv_sec)
                return 1;
        return lhs->tv_usec - rhs->tv_usec;
}

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);

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

/*
 * timespec_add_safe assumes both values are positive and checks
 * for overflow. It will return TIME_T_MAX if the reutrn would be
 * smaller then either of the arguments.
 */
extern struct timespec timespec_add_safe(const struct timespec lhs,
                                         const struct timespec rhs);


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;
}

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 gran);

#define CURRENT_TIME            (current_kernel_time())
#define CURRENT_TIME_SEC        ((struct timespec) { get_seconds(), 0 })

/* Some architectures do not supply their own clocksource.
 * This is mainly the case in architectures that get their
 * inter-tick times by reading the counter on their interval
 * timer. Since these timers wrap every tick, they're not really
 * useful as clocksources. Wrapping them to act like one is possible
 * but not very efficient. So we provide a callout these arches
 * can implement for use with the jiffies clocksource to provide
 * finer then tick granular time.
 */
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
extern u32 (*arch_gettimeoffset)(void);
#endif

struct itimerval;
extern int do_setitimer(int which, struct itimerval *value,
                        struct itimerval *ovalue);
extern int do_getitimer(int which, struct itimerval *value);

extern unsigned int alarm_setitimer(unsigned int seconds);

extern long do_utimes(int dfd, const char __user *filename, struct timespec *times, int flags);

struct tms;
extern void do_sys_times(struct tms *);

/*
 * Similar to the struct tm in userspace <time.h>, but it needs to be here so
 * that the kernel source is self contained.
 */
struct tm {
        /*
         * the number of seconds after the minute, normally in the range
         * 0 to 59, but can be up to 60 to allow for leap seconds
         */
        int tm_sec;
        /* the number of minutes after the hour, in the range 0 to 59*/
        int tm_min;
        /* the number of hours past midnight, in the range 0 to 23 */
        int tm_hour;
        /* the day of the month, in the range 1 to 31 */
        int tm_mday;
        /* the number of months since January, in the range 0 to 11 */
        int tm_mon;
        /* the number of years since 1900 */
        long tm_year;
        /* the number of days since Sunday, in the range 0 to 6 */
        int tm_wday;
        /* the number of days since January 1, in the range 0 to 365 */
        int tm_yday;
};

void time_to_tm(time_t totalsecs, int offset, struct tm *result);

/**
 * 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;
}

/**
 * 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_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);

/**
 * 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);

/**
 * 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