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//! This module contains a newtype `Timex` wrapping an inner `libc::timex`, which allows construction
//! only of valid values for the sake of the types of `adjtimex`/`ntp_adjtime` calls we'll make in ClockBound.
use bon::bon;
#[cfg(not(target_os = "macos"))]
use libc::timeval;
use libc::{
ADJ_SETOFFSET, MOD_NANO, MOD_OFFSET, MOD_STATUS, MOD_TIMECONST, STA_NANO, STA_PLL, timex,
};
use tracing::warn;
use crate::daemon::time::{Duration, Instant, tsc::Skew};
/// Newtype wrapping `libc::timex` to provide valid
/// constructors for each type of `adjtimex`/`ntp_adjtime` operation.
#[derive(Debug, PartialEq, Clone)]
pub struct Timex(timex);
#[bon]
impl Timex {
/// Maximum phase offset that can be submitted to the kernel PLL in a single
/// `adjtimex` call. Offsets larger than this are clamped by the `Timex`
/// constructors. The state machine also uses this value as the threshold above
/// which a step correction is preferred over a smooth slew.
pub const MAX_PHASE_OFFSET: Duration = Duration::from_millis(500);
/// Expose a mutable reference to the inner `libc::timex`.
pub fn expose(&mut self) -> *mut timex {
&raw mut self.0
}
/// Read the given `time` from the underlying `timex`. The kernel
/// generally returns this with the time set to the current `CLOCK_REALTIME`
/// reading.
///
/// Notably, this same field is used in `ADJ_SETOFFSET` mode calls in order to supply an
/// offset value.
///
/// The value may be expressed in microseconds by default, but if the call is made
/// with `status` bit `STA_NANO` set, `tv_usec` represents a nanosecond value.
pub fn time(&self) -> Instant {
let tv = self.0.time;
let fractional_part = if self.0.status & STA_NANO > 0 {
Duration::from_nanos(tv.tv_usec)
} else {
Duration::from_micros(tv.tv_usec)
};
Instant::from_secs(tv.tv_sec) + fractional_part
}
/// Reads the given `freq` from the underlying `timex`.
///
/// In struct timex, freq, ppsfreq, and stabil are ppm (parts per
/// million) with a 16-bit fractional part, which means that a value
/// of 1 in one of those fields actually means 2^-16 ppm, and
/// 2^16=65536 is 1 ppm. This is the case for both input values (in
/// the case of freq) and output values.
/// ref: See NOTES in <https://man7.org/linux/man-pages/man2/adjtimex.2.html>
///
/// This function constructs a `Skew` value from the given `freq` value set on the `timex`.
pub fn freq(&self) -> Skew {
Skew::from_timex_freq(self.0.freq)
}
#[allow(
clippy::cast_possible_truncation,
reason = "offset is clamped then converted so no truncation"
)]
pub fn apply_phase_correction(mut offset: Duration) -> Self {
if offset > Self::MAX_PHASE_OFFSET || offset < -Self::MAX_PHASE_OFFSET {
warn!(
"Offset of {}ns is outside of bounds +/-{}ns. Clamping the value.",
offset.as_nanos(),
Self::MAX_PHASE_OFFSET.as_nanos()
);
offset = offset.clamp(-Self::MAX_PHASE_OFFSET, Self::MAX_PHASE_OFFSET);
}
Self(timex {
modes: MOD_OFFSET | MOD_TIMECONST | MOD_NANO | MOD_STATUS,
offset: offset.as_nanos_trunc(),
freq: 0,
maxerror: 0,
esterror: 0,
status: STA_PLL,
constant: 0,
precision: 0,
tolerance: 0,
#[cfg(not(target_os = "macos"))]
time: timeval {
tv_sec: 0,
tv_usec: 0,
},
#[cfg(not(target_os = "macos"))]
tick: 0,
ppsfreq: 0,
jitter: 0,
shift: 0,
stabil: 0,
jitcnt: 0,
calcnt: 0,
errcnt: 0,
stbcnt: 0,
#[cfg(not(target_os = "macos"))]
tai: 0,
#[cfg(not(target_os = "macos"))]
__unused1: 0,
#[cfg(not(target_os = "macos"))]
__unused2: 0,
#[cfg(not(target_os = "macos"))]
__unused3: 0,
#[cfg(not(target_os = "macos"))]
__unused4: 0,
#[cfg(not(target_os = "macos"))]
__unused5: 0,
#[cfg(not(target_os = "macos"))]
__unused6: 0,
#[cfg(not(target_os = "macos"))]
__unused7: 0,
#[cfg(not(target_os = "macos"))]
__unused8: 0,
#[cfg(not(target_os = "macos"))]
__unused9: 0,
#[cfg(not(target_os = "macos"))]
__unused10: 0,
#[cfg(not(target_os = "macos"))]
__unused11: 0,
})
}
/// Construct a `libc::timex` used for stepping the clock by some phase correction,
/// with a full step (can go forwards or backwards).
/// This is used to set the system clock to the current time, which is useful for
/// initializing the clock after a reboot.
///
/// `ADJ_SETOFFSET` is only supported on Linux `adjtimex`, in the future we should have some implementation
/// for other platforms e.g. FreeBSD
#[cfg(target_os = "linux")]
#[allow(
clippy::field_reassign_with_default,
reason = "false positive, can't use default constructor for inner type fields mutated"
)]
#[builder]
pub fn clock_step(phase_correction: Duration) -> Self {
Self(timex {
// Set `modes` bits for `ADJ_SETOFFSET` to step the clock, and MOD_NANO to use nanosecond units
modes: ADJ_SETOFFSET | MOD_NANO,
offset: 0,
freq: 0,
maxerror: 0,
esterror: 0,
status: 0,
constant: 0,
precision: 0,
tolerance: 0,
// `ADJ_SETOFFSET` uses `time` rather than offset field to indicate how much to step the clock
#[cfg(not(target_os = "macos"))]
time: phase_correction.to_timeval_nanos(),
#[cfg(not(target_os = "macos"))]
tick: 0,
ppsfreq: 0,
jitter: 0,
shift: 0,
stabil: 0,
jitcnt: 0,
calcnt: 0,
errcnt: 0,
stbcnt: 0,
#[cfg(not(target_os = "macos"))]
tai: 0,
#[cfg(not(target_os = "macos"))]
__unused1: 0,
#[cfg(not(target_os = "macos"))]
__unused2: 0,
#[cfg(not(target_os = "macos"))]
__unused3: 0,
#[cfg(not(target_os = "macos"))]
__unused4: 0,
#[cfg(not(target_os = "macos"))]
__unused5: 0,
#[cfg(not(target_os = "macos"))]
__unused6: 0,
#[cfg(not(target_os = "macos"))]
__unused7: 0,
#[cfg(not(target_os = "macos"))]
__unused8: 0,
#[cfg(not(target_os = "macos"))]
__unused9: 0,
#[cfg(not(target_os = "macos"))]
__unused10: 0,
#[cfg(not(target_os = "macos"))]
__unused11: 0,
})
}
/// Completely zeroed, allows for retrieving the current kernel values
pub fn retrieve() -> Self {
Self(timex {
modes: 0,
offset: 0,
freq: 0,
maxerror: 0,
esterror: 0,
status: 0,
constant: 0,
precision: 0,
tolerance: 0,
#[cfg(not(target_os = "macos"))]
time: timeval {
tv_sec: 0,
tv_usec: 0,
},
#[cfg(not(target_os = "macos"))]
tick: 0,
ppsfreq: 0,
jitter: 0,
shift: 0,
stabil: 0,
jitcnt: 0,
calcnt: 0,
errcnt: 0,
stbcnt: 0,
#[cfg(not(target_os = "macos"))]
tai: 0,
#[cfg(not(target_os = "macos"))]
__unused1: 0,
#[cfg(not(target_os = "macos"))]
__unused2: 0,
#[cfg(not(target_os = "macos"))]
__unused3: 0,
#[cfg(not(target_os = "macos"))]
__unused4: 0,
#[cfg(not(target_os = "macos"))]
__unused5: 0,
#[cfg(not(target_os = "macos"))]
__unused6: 0,
#[cfg(not(target_os = "macos"))]
__unused7: 0,
#[cfg(not(target_os = "macos"))]
__unused8: 0,
#[cfg(not(target_os = "macos"))]
__unused9: 0,
#[cfg(not(target_os = "macos"))]
__unused10: 0,
#[cfg(not(target_os = "macos"))]
__unused11: 0,
})
}
// Helper function to create a dummy Timex for `NoopClockAdjuster`.
#[cfg(feature = "test-side-by-side")]
pub fn create_dummy_timex() -> Timex {
Timex(timex {
modes: 0,
offset: 0,
freq: 0,
maxerror: 0,
esterror: 0,
status: 0,
constant: 0,
precision: 0,
tolerance: 0,
#[cfg(not(target_os = "macos"))]
time: timeval {
tv_sec: 0,
tv_usec: 0,
},
#[cfg(not(target_os = "macos"))]
tick: 0,
ppsfreq: 0,
jitter: 0,
shift: 0,
stabil: 0,
jitcnt: 0,
calcnt: 0,
errcnt: 0,
stbcnt: 0,
#[cfg(not(target_os = "macos"))]
tai: 0,
#[cfg(not(target_os = "macos"))]
__unused1: 0,
#[cfg(not(target_os = "macos"))]
__unused2: 0,
#[cfg(not(target_os = "macos"))]
__unused3: 0,
#[cfg(not(target_os = "macos"))]
__unused4: 0,
#[cfg(not(target_os = "macos"))]
__unused5: 0,
#[cfg(not(target_os = "macos"))]
__unused6: 0,
#[cfg(not(target_os = "macos"))]
__unused7: 0,
#[cfg(not(target_os = "macos"))]
__unused8: 0,
#[cfg(not(target_os = "macos"))]
__unused9: 0,
#[cfg(not(target_os = "macos"))]
__unused10: 0,
#[cfg(not(target_os = "macos"))]
__unused11: 0,
})
}
}
impl AsRef<timex> for Timex {
fn as_ref(&self) -> &timex {
&self.0
}
}
#[cfg(test)]
mod test {
use libc::{STA_NANO, timeval};
use rstest::rstest;
use super::*;
#[rstest]
#[case::positive(
Duration::from_millis(100),
timeval {tv_sec: 0, tv_usec: 100_000_000},
)]
#[case::negative(
-Duration::from_millis(100),
timeval {tv_sec: -1, tv_usec: 900_000_000},
)]
#[case::zero(
Duration::from_millis(0),
timeval {tv_sec: 0, tv_usec: 0},
)]
fn test_timex_clock_step(#[case] phase_correction: Duration, #[case] expected_time: timeval) {
let binding = Timex::clock_step()
.phase_correction(phase_correction)
.call();
let tx = binding.as_ref();
assert_eq!(tx.time, expected_time);
// assert modes is set properly for our adjustment
assert_eq!(tx.modes, ADJ_SETOFFSET | MOD_NANO);
}
// Helper function to create a Timex with custom time and status values
fn create_timex_with_time(tv_sec: i64, tv_usec: i64, status: i32) -> Timex {
Timex(timex {
modes: 0,
offset: 0,
freq: 0,
maxerror: 0,
esterror: 0,
status,
constant: 0,
precision: 0,
tolerance: 0,
#[cfg(not(target_os = "macos"))]
time: timeval { tv_sec, tv_usec },
#[cfg(not(target_os = "macos"))]
tick: 0,
ppsfreq: 0,
jitter: 0,
shift: 0,
stabil: 0,
jitcnt: 0,
calcnt: 0,
errcnt: 0,
stbcnt: 0,
#[cfg(not(target_os = "macos"))]
tai: 0,
#[cfg(not(target_os = "macos"))]
__unused1: 0,
#[cfg(not(target_os = "macos"))]
__unused2: 0,
#[cfg(not(target_os = "macos"))]
__unused3: 0,
#[cfg(not(target_os = "macos"))]
__unused4: 0,
#[cfg(not(target_os = "macos"))]
__unused5: 0,
#[cfg(not(target_os = "macos"))]
__unused6: 0,
#[cfg(not(target_os = "macos"))]
__unused7: 0,
#[cfg(not(target_os = "macos"))]
__unused8: 0,
#[cfg(not(target_os = "macos"))]
__unused9: 0,
#[cfg(not(target_os = "macos"))]
__unused10: 0,
#[cfg(not(target_os = "macos"))]
__unused11: 0,
})
}
#[test]
fn test_get_time_microsecond_precision_without_sta_nano() {
// Test that without STA_NANO flag, tv_usec is interpreted as microseconds
let timex = create_timex_with_time(1, 123_456, 0);
let result = timex.time();
let expected = Instant::from_secs(1) + Duration::from_micros(123_456);
assert_eq!(result, expected);
}
#[test]
fn test_get_time_nanosecond_precision_with_sta_nano() {
// Test that with STA_NANO flag, tv_usec is interpreted as nanoseconds
let timex = create_timex_with_time(1, 123_456_789, STA_NANO);
let result = timex.time();
let expected = Instant::from_secs(1) + Duration::from_nanos(123_456_789);
assert_eq!(result, expected);
}
#[test]
fn test_get_time_zero_values() {
// Test epoch time (zero values)
let timex = create_timex_with_time(0, 0, 0);
let result = timex.time();
assert_eq!(result, Instant::UNIX_EPOCH);
}
#[test]
fn test_get_time_negative_seconds() {
// Test negative seconds (before epoch)
let timex = create_timex_with_time(-10, 500_000, 0);
let result = timex.time();
let expected = Instant::from_secs(-10) + Duration::from_micros(500_000);
assert_eq!(result, expected);
}
}