/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2018 Red Hat, Inc.
*/
#include "nm-default.h"
#include "nm-time-utils.h"
#include "nm-logging-fwd.h"
/*****************************************************************************/
typedef struct {
/* the offset to the native clock, in seconds. */
gint64 offset_sec;
clockid_t clk_id;
} GlobalState;
static const GlobalState *volatile p_global_state;
static const GlobalState *
_t_init_global_state(void)
{
static GlobalState global_state = {};
static gsize init_once = 0;
const GlobalState *p;
clockid_t clk_id;
struct timespec tp;
gint64 offset_sec;
int r;
clk_id = CLOCK_BOOTTIME;
r = clock_gettime(clk_id, &tp);
if (r == -1 && errno == EINVAL) {
clk_id = CLOCK_MONOTONIC;
r = clock_gettime(clk_id, &tp);
}
/* The only failure we tolerate is that CLOCK_BOOTTIME is not supported.
* Other than that, we rely on kernel to not fail on this. */
g_assert(r == 0);
g_assert(tp.tv_nsec >= 0 && tp.tv_nsec < NM_UTILS_NSEC_PER_SEC);
/* Calculate an offset for the time stamp.
*
* We always want positive values, because then we can initialize
* a timestamp with 0 and be sure, that it will be less then any
* value nm_utils_get_monotonic_timestamp_*() might return.
* For this to be true also for nm_utils_get_monotonic_timestamp_sec() at
* early boot, we have to shift the timestamp to start counting at
* least from 1 second onward.
*
* Another advantage of shifting is, that this way we make use of the whole 31 bit
* range of signed int, before the time stamp for nm_utils_get_monotonic_timestamp_sec()
* wraps (~68 years).
**/
offset_sec = (-((gint64) tp.tv_sec)) + 1;
if (!g_once_init_enter(&init_once)) {
/* there was a race. We expect the pointer to be fully initialized now. */
p = g_atomic_pointer_get(&p_global_state);
g_assert(p);
return p;
}
global_state.offset_sec = offset_sec;
global_state.clk_id = clk_id;
p = &global_state;
g_atomic_pointer_set(&p_global_state, p);
g_once_init_leave(&init_once, 1);
_nm_utils_monotonic_timestamp_initialized(&tp, p->offset_sec, p->clk_id == CLOCK_BOOTTIME);
return p;
}
#define _t_get_global_state() \
({ \
const GlobalState *_p; \
\
_p = g_atomic_pointer_get(&p_global_state); \
(G_LIKELY(_p) ? _p : _t_init_global_state()); \
})
#define _t_clock_gettime_eval(p, tp) \
({ \
struct timespec *const _tp = (tp); \
const GlobalState *const _p2 = (p); \
int _r; \
\
nm_assert(_tp); \
\
_r = clock_gettime(_p2->clk_id, _tp); \
\
nm_assert(_r == 0); \
nm_assert(_tp->tv_nsec >= 0 && _tp->tv_nsec < NM_UTILS_NSEC_PER_SEC); \
\
_p2; \
})
#define _t_clock_gettime(tp) _t_clock_gettime_eval(_t_get_global_state(), tp);
/*****************************************************************************/
/**
* nm_utils_get_monotonic_timestamp_nsec:
*
* Returns: a monotonically increasing time stamp in nanoseconds,
* starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME.
*
* The returned value will start counting at an undefined point
* in the past and will always be positive.
*
* All the nm_utils_get_monotonic_timestamp_*sec functions return the same
* timestamp but in different scales (nsec, usec, msec, sec).
**/
gint64
nm_utils_get_monotonic_timestamp_nsec(void)
{
const GlobalState *p;
struct timespec tp;
p = _t_clock_gettime(&tp);
/* Although the result will always be positive, we return a signed
* integer, which makes it easier to calculate time differences (when
* you want to subtract signed values).
**/
return (((gint64) tp.tv_sec) + p->offset_sec) * NM_UTILS_NSEC_PER_SEC + tp.tv_nsec;
}
/**
* nm_utils_get_monotonic_timestamp_usec:
*
* Returns: a monotonically increasing time stamp in microseconds,
* starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME.
*
* The returned value will start counting at an undefined point
* in the past and will always be positive.
*
* All the nm_utils_get_monotonic_timestamp_*sec functions return the same
* timestamp but in different scales (nsec, usec, msec, sec).
**/
gint64
nm_utils_get_monotonic_timestamp_usec(void)
{
const GlobalState *p;
struct timespec tp;
p = _t_clock_gettime(&tp);
/* Although the result will always be positive, we return a signed
* integer, which makes it easier to calculate time differences (when
* you want to subtract signed values).
**/
return (((gint64) tp.tv_sec) + p->offset_sec) * ((gint64) G_USEC_PER_SEC)
+ (tp.tv_nsec / (NM_UTILS_NSEC_PER_SEC / G_USEC_PER_SEC));
}
/**
* nm_utils_get_monotonic_timestamp_msec:
*
* Returns: a monotonically increasing time stamp in milliseconds,
* starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME.
*
* The returned value will start counting at an undefined point
* in the past and will always be positive.
*
* All the nm_utils_get_monotonic_timestamp_*sec functions return the same
* timestamp but in different scales (nsec, usec, msec, sec).
**/
gint64
nm_utils_get_monotonic_timestamp_msec(void)
{
const GlobalState *p;
struct timespec tp;
p = _t_clock_gettime(&tp);
/* Although the result will always be positive, we return a signed
* integer, which makes it easier to calculate time differences (when
* you want to subtract signed values).
**/
return (((gint64) tp.tv_sec) + p->offset_sec) * ((gint64) 1000)
+ (tp.tv_nsec / (NM_UTILS_NSEC_PER_SEC / 1000));
}
/**
* nm_utils_get_monotonic_timestamp_sec:
*
* Returns: nm_utils_get_monotonic_timestamp_msec() in seconds (throwing
* away sub second parts). The returned value will always be positive.
*
* This value wraps after roughly 68 years which should be fine for any
* practical purpose.
*
* All the nm_utils_get_monotonic_timestamp_*sec functions return the same
* timestamp but in different scales (nsec, usec, msec, sec).
**/
gint32
nm_utils_get_monotonic_timestamp_sec(void)
{
const GlobalState *p;
struct timespec tp;
p = _t_clock_gettime(&tp);
return (((gint64) tp.tv_sec) + p->offset_sec);
}
/**
* nm_utils_monotonic_timestamp_as_boottime:
* @timestamp: the monotonic-timestamp that should be converted into CLOCK_BOOTTIME.
* @timestamp_nsec_per_tick: How many nanoseconds make one unit of @timestamp? E.g. if
* @timestamp is in unit seconds, pass %NM_UTILS_NSEC_PER_SEC; if @timestamp is
* in nanoseconds, pass 1; if @timestamp is in milliseconds, pass %NM_UTILS_NSEC_PER_SEC/1000.
* This must be a multiple of 10, and between 1 and %NM_UTILS_NSEC_PER_SEC.
*
* Returns: the monotonic-timestamp as CLOCK_BOOTTIME, as returned by clock_gettime().
* The unit is the same as the passed in @timestamp based on @timestamp_nsec_per_tick.
* E.g. if you passed @timestamp in as seconds, it will return boottime in seconds.
*
* Note that valid monotonic-timestamps are always positive numbers (counting roughly since
* the application is running). However, it might make sense to calculate a timestamp from
* before the application was running, hence negative @timestamp is allowed. The result
* in that case might also be a negative timestamp (in CLOCK_BOOTTIME), which would indicate
* that the timestamp lies in the past before the machine was booted.
*
* On older kernels that don't support CLOCK_BOOTTIME, the returned time is instead CLOCK_MONOTONIC.
**/
gint64
nm_utils_monotonic_timestamp_as_boottime(gint64 timestamp, gint64 timestamp_nsec_per_tick)
{
const GlobalState *p;
gint64 offset;
/* only support nsec-per-tick being a multiple of 10. */
g_return_val_if_fail(timestamp_nsec_per_tick == 1
|| (timestamp_nsec_per_tick > 0
&& timestamp_nsec_per_tick <= NM_UTILS_NSEC_PER_SEC
&& timestamp_nsec_per_tick % 10 == 0),
-1);
/* if the caller didn't yet ever fetch a monotonic-timestamp, he cannot pass any meaningful
* value (because he has no idea what these timestamps would be). That would be a bug. */
nm_assert(g_atomic_pointer_get(&p_global_state));
p = _t_get_global_state();
nm_assert(p->offset_sec <= 0);
/* calculate the offset of monotonic-timestamp to boottime. offset_s is <= 1. */
offset = p->offset_sec * (NM_UTILS_NSEC_PER_SEC / timestamp_nsec_per_tick);
nm_assert(offset <= 0 && offset > G_MININT64);
/* check for overflow (note that offset is non-positive). */
g_return_val_if_fail(timestamp < G_MAXINT64 + offset, G_MAXINT64);
return timestamp - offset;
}
/**
* nm_utils_monotonic_timestamp_from_boottime:
* @boottime: the timestamp from CLOCK_BOOTTIME (or CLOCK_MONOTONIC, if
* kernel does not support CLOCK_BOOTTIME and monotonic timestamps are based
* on CLOCK_MONOTONIC).
* @timestamp_nsec_per_tick: the scale in which @boottime is. If @boottime is in
* nano seconds, this should be 1. If it is in milli seconds, this should be
* %NM_UTILS_NSEC_PER_SEC/1000, etc.
*
* Returns: the same timestamp in monotonic timestamp scale.
*
* Note that commonly monotonic timestamps are positive. But they may not
* be positive in this case. That's when boottime is taken from a time before
* the monotonic timestamps started counting. So, that means a zero or negative
* value is still a valid timestamp.
*
* This is the inverse of nm_utils_monotonic_timestamp_as_boottime().
*/
gint64
nm_utils_monotonic_timestamp_from_boottime(guint64 boottime, gint64 timestamp_nsec_per_tick)
{
const GlobalState *p;
gint64 offset;
/* only support nsec-per-tick being a multiple of 10. */
g_return_val_if_fail(timestamp_nsec_per_tick == 1
|| (timestamp_nsec_per_tick > 0
&& timestamp_nsec_per_tick <= NM_UTILS_NSEC_PER_SEC
&& timestamp_nsec_per_tick % 10 == 0),
-1);
p = _t_get_global_state();
nm_assert(p->offset_sec <= 0);
/* calculate the offset of monotonic-timestamp to boottime. offset_s is <= 1. */
offset = p->offset_sec * (NM_UTILS_NSEC_PER_SEC / timestamp_nsec_per_tick);
nm_assert(offset <= 0 && offset > G_MININT64);
/* check for overflow (note that offset is non-positive). */
g_return_val_if_fail(boottime < G_MAXINT64, G_MAXINT64);
return (gint64) boottime + offset;
}
gint64
nm_utils_clock_gettime_nsec(clockid_t clockid)
{
struct timespec tp;
if (clock_gettime(clockid, &tp) != 0)
return -NM_ERRNO_NATIVE(errno);
return nm_utils_timespec_to_nsec(&tp);
}
gint64
nm_utils_clock_gettime_msec(clockid_t clockid)
{
struct timespec tp;
if (clock_gettime(clockid, &tp) != 0)
return -NM_ERRNO_NATIVE(errno);
return nm_utils_timespec_to_msec(&tp);
}