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From: Paul Thomas <pthomas8589@gmail.com>
To: kerolasa@gmail.com
Cc: util-linux <util-linux@vger.kernel.org>
Subject: Re: last reboot
Date: Tue, 10 Sep 2019 10:04:52 -0400
Message-ID: <CAD56B7c38z364xNk32cOuAaWKRiq+RwPOLUx3WwMuqT7bSsvDQ@mail.gmail.com> (raw)
In-Reply-To: <CAG27Bk2efpSwz97CHom4Mr0N+LSmFh1qT4rDeb9jF=2VVqfc0g@mail.gmail.com>

Hi Sami,

>
> The last(1) is pretty simple tool.  It can and will display information
> tracked in utmp(5) data.
>
> http://man7.org/linux/man-pages/man5/utmp.5.html
Thanks for the information.

>
> The utmp data is stored over many many reboots, that might stay around for
> years.  Notice that changing utmp(5) is probably not the easiest thing to
Yes, staying around for years with an entry for each boot would be desirable.

> achieve.  That format is part of POSIX.  Assuming standards are changed then
> update to various libc implementations is needed as well.
>
> Alternatively some sort of extented-utmp format could be created to avoid
> standardization work, but getting that to adopted might be hard.  While utmp
> has it's flaws it is not exactly broken.  In short while I'm not strictly
> against better reboot reason tracking I am a somewhat doubtful how feasible
> this work is.
OK, this makes sense. I might do something simple for our use case.

>
> That said what is that memtool?  I have never noticed it before.  By glance
> it looks a little like abandonware.  Maybe it could be get a home in
> util-linux if a tool like that is found to be useful, and old maintainer
> does not mind.
I'm not sure what the current state is, but it's included in the latest debian:
https://packages.debian.org/buster/memtool

It's a very simple (if not dangerous) tool to r/w /dev/mem. But it's very handy
for spying on memory mapped I/O registers like in this case.

I guess adding an interface isn't any worse than /dev/mem directly, but it
still might not be desirable to have it on every system?

-Paul

      reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-09 19:07 Paul Thomas
2019-09-10 13:44 ` Sami Kerola
2019-09-10 14:04   ` Paul Thomas [this message]

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