Function StoreFBClockDataRealtime

fbclock/shmem_notlinux.go:256–266

StoreFBClockDataRealtime writes the realtime anchor section, used on hosts whose primary is MONOTONIC_RAW. Separate call from StoreFBClockDataV2 so the daemon can publish the primary anchor before the slower REALTIME read.

(fd uintptr, d DataV2)

// whose primary is MONOTONIC_RAW. Separate call from StoreFBClockDataV2 so the
// daemon can publish the primary anchor before the slower REALTIME read.
func StoreFBClockDataRealtime(fd uintptr, d DataV2) error {
	data, err := unix.Mmap(int(fd), 0, shmDataV2Size, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED) //nolint:gosec
	if err != nil {
		return fmt.Errorf("mmap failed: %w", err)
	}
	defer func() { _ = unix.Munmap(data) }()

	return storeSeqlockSection(data, shmV2RealtimeSeqOff, func(buf []byte) {
		writeClockDataV2(buf, d)
	})
}

// ReadFBClockDataV2 reads the primary anchor section. Used in tests only.
func ReadFBClockDataV2(shmp unsafe.Pointer) (*DataV2, error) {