Set up WSL2 clock sync

setup-wsl-clock-sync.cmd

@echo off
rem this is a programmatic reminder of how to set up wsl clock sync
rem to prevent clock drift after sleep etc
rem see https://stackoverflow.com/a/65086857/120398 and https://github.com/microsoft/WSL/issues/5324

set WSL_UTF8=1
setlocal EnableDelayedExpansion
for /F "tokens=* delims=" %%D in ('wsl --list --quiet') DO (
    set hwclock_count=0
	for /f "tokens=* delims=" %%C in ('wsl -d %%D bash -c "grep -c hwclock /usr/local/sbin/hwclock-sync 2>/dev/null"') DO set hwclock_count=%%C
	if !hwclock_count! neq 1 (
	  echo Creating script to retry syncing
      wsl -d %%D sudo bash -c "{ echo '#!/bin/bash' ; echo 'for try in 1 2 3 4 5; do /usr/sbin/hwclock -s && break || { echo sync failed, retrying >&2 ; sleep 10 ; } done' ; } > /usr/local/sbin/hwclock-sync ; chmod a+x /usr/local/sbin/hwclock-sync"
	)
	set hwclock_count=0
	for /f "tokens=* delims=" %%C in ('wsl -d %%D bash -c "grep -c hwclock /etc/sudoers.d/hwclock 2>/dev/null"') DO set hwclock_count=%%C
	if !hwclock_count! neq 1 (
		echo Setting up sudo permissions for hwclock on distro %%D - will prompt for password...
		wsl -d %%D sudo bash -c "echo -e '\x25adm ALL=(ALL)  NOPASSWD:/usr/local/sbin/hwclock-sync' > /etc/sudoers.d/hwclock"
	) else echo hwclock permissions already set up with !hwclock_count! - not changing...
	echo Testing resetting the clock - shouldn't prompt for password...
    wsl -d %%D sudo /usr/local/sbin/hwclock-sync
	set syncname=WSLClockSync%%D
	echo Creating scheduled task !syncname!...
	schtasks /create /f /tn "!syncname!" /tr "wsl.exe sudo /usr/local/sbin/hwclock-sync" /sc onevent /ec system /mo "*[System[Provider[@Name='Microsoft-Windows-Kernel-General'] and (EventID=1)]]"
	echo Scheduling !syncname! to run even when on batteries...
	powershell -command "& {Set-ScheduledTask !syncname! -Settings (New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries)}"
	echo Done!
)