include/linux/time64.h

Source file repositories/reference/linux-study-clean/include/linux/time64.h

File Facts

System
Linux kernel
Corpus path
include/linux/time64.h
Extension
.h
Size
4793 bytes
Lines
177
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct timespec64 {
	time64_t	tv_sec;			/* seconds */
	long		tv_nsec;		/* nanoseconds */
};

struct itimerspec64 {
	struct timespec64 it_interval;
	struct timespec64 it_value;
};

/* Parameters used to convert the timespec values: */
#define PSEC_PER_NSEC			1000L

/* Located here for timespec[64]_valid_strict */
#define TIME64_MAX			((s64)~((u64)1 << 63))
#define TIME64_MIN			(-TIME64_MAX - 1)

#define KTIME_MAX			((s64)~((u64)1 << 63))
#define KTIME_MIN			(-KTIME_MAX - 1)
#define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
#define KTIME_SEC_MIN			(KTIME_MIN / NSEC_PER_SEC)

/*
 * Limits for settimeofday():
 *
 * To prevent setting the time close to the wraparound point time setting
 * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
 * should be really sufficient, which means the cutoff is 2232. At that
 * point the cutoff is just a small part of the larger problem.
 */
#define TIME_UPTIME_SEC_MAX		(30LL * 365 * 24 *3600)
#define TIME_SETTOD_SEC_MAX		(KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)

static inline int timespec64_equal(const struct timespec64 *a,
				   const struct timespec64 *b)
{
	return (a->tv_sec == b->tv_sec) && (a->tv_nsec == b->tv_nsec);
}

static inline bool timespec64_is_epoch(const struct timespec64 *ts)
{
	return ts->tv_sec == 0 && ts->tv_nsec == 0;
}

/*
 * lhs < rhs:  return <0
 * lhs == rhs: return 0
 * lhs > rhs:  return >0
 */
static inline int timespec64_compare(const struct timespec64 *lhs, const struct timespec64 *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_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec);

static inline struct timespec64 timespec64_add(struct timespec64 lhs,
						struct timespec64 rhs)
{
	struct timespec64 ts_delta;
	set_normalized_timespec64(&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 timespec64 timespec64_sub(struct timespec64 lhs,
						struct timespec64 rhs)
{
	struct timespec64 ts_delta;
	set_normalized_timespec64(&ts_delta, lhs.tv_sec - rhs.tv_sec,
				lhs.tv_nsec - rhs.tv_nsec);
	return ts_delta;
}

/*
 * Returns true if the timespec64 is norm, false if denorm:
 */
static inline bool timespec64_valid(const struct timespec64 *ts)
{
	/* Dates before 1970 are bogus */
	if (ts->tv_sec < 0)
		return false;
	/* Can't have more nanoseconds then a second */

Annotation

Implementation Notes