systemctl status erases PID file after hibernate on WSL2

[MarkUsingGithub]

The boot time of a container is not stable when running a container in WSL.
For example

sh-4.4# date -d @$(awk '/btime/ {print $2}' /proc/stat)
Thu Jul 10 05:42:14 UTC 2025
sh-4.4# w
 09:32:16 up  3:50,  0 users,  load average: 0.25, 0.21, 0.18
... Hibernate....
sh-4.4# date -d @$(awk '/btime/ {print $2}' /proc/stat)
Thu Jul 10 06:22:11 UTC 2025
... Boot time increased with 40minutes...
sh-4.4# w
 11:31:27 up  5:09,  0 users,  load average: 0.19, 0.13, 0.17
... And is stable without hibernate

Problem with this is that a PID file created before the sleep/hibernate may be erased by the truncate_old function:

        logg.warning("NLMSCHE: truncating: %s", filename)
        filetime = self.get_filetime(filename)
        boottime = self.get_boottime()
        if filetime >= boottime:
            if DEBUG_BOOTTIME:
                logg.debug("  file time: %s (%s)", datetime.datetime.fromtimestamp(filetime), o22(filename))
                logg.debug("  boot time: %s (%s)", datetime.datetime.fromtimestamp(boottime), "status modified later")
            return False # OK
        if DEBUG_BOOTTIME:
            logg.info("  file time: %s (%s)", datetime.datetime.fromtimestamp(filetime), o22(filename))
            logg.info("  boot time: %s (%s)", datetime.datetime.fromtimestamp(boottime), "status TRUNCATED NOW")
        try:
            shutil_truncate(filename)

In my opinion the code to determine the boot time can be simplified: simply use mtime from /proc directly:

    def get_boottime_from_proc(self):
        """ detects the latest boot time by looking at the creation time of /proc"""
        return os.path.getmtime(_proc_pid_dir)