[Nut-upsuser] NUT command LOGIN is not a login

[Jim Klimov]

Sounds correct to me too, after browsing the code a bit recently when I was
adding the new names for old concepts.

As for login the word, here a client (upsmon) logs into the server (upsd)
to be counted and informed about FSD due to a particular UPS going
critical, if I got that correctly.

Logins to web sites also don't give us a shell ;)


On Thu, Jun 24, 2021, 15:22 Manuel Wolfshant <wolfy at nobugconsulting.ro>
wrote:

> On 6/24/21 3:48 PM, Roger Price wrote:
> > During the ISE review of the proposed RFC, the IETF editor has asked
> > for clarification of the LOGIN command, since he, like most people,
> > assumes that "LOGIN" means something like "login to a shell".
> >
> > The Developer Guide Chapter 9
> > https://networkupstools.org/docs/developer-guide.chunked/ar01s09.html
> > "Network Protocol Information" says
> >
> >  9.9. LOGIN
> >
> >  LOGIN <upsname>    Response: OK (upon success) or various errors
> >
> >  Note This requires "upsmon slave" or "upsmon master" in upsd.users
> >
> >  Use this to log the fact that a system is drawing power from this
> > UPS. The
> >  upsmon master will wait until the count of attached systems reaches 1
> > - itself.
> >  This allows the slaves to shut down first.
> >
> >  Note You probably shouldn’t send this command unless you are upsmon,
> > or a
> >  upsmon replacement.
> >
> >  9.4 GET NUMLOGINS <upsname>
> >  Response: NUMLOGINS <UPSNAME> <VALUE>
> >
> >  where <value> is the number of clients which have done LOGIN for this
> > UPS. This
> >  is used by the master upsmon to determine how many clients are still
> > connected
> >  when starting the shutdown process.
> >
> > I propose saying:
> >
> > Figure 4                                 "The client"
> >            ,--------------------,---------------------,
> >  ,-----,   |     UPS       <-Commands      Primary    |
> >  |     |---|  Attachment        |         Management  |   Primary
> >  |     |===|    Daemon       Responses->    Daemon    |
> >  |     |   '--------------------'---------------------'
> >  | UPS |            ^
> >  |     |            '<-Commands---Responses->,
> >  |     |                                     v
> >  |     |            ,--------------,-----------------,
> >  |     |============|              |     Secondary   |
> >  /-----\            |              |     Management  |   Secondary
> >                     |              |       Daemon    |
> >                     '--------------'-----------------'
> >
> > LOGIN is not the conventional user access to a shell. In a
> > configuration such as Figure 4 in which a UPS protects more than one
> > system, the Primary (2.8) Management Daemon (2.6), upsmon, needs to
> > know how many Secondaries (2.9) are currently "active", i.e. powered
> > by the UPS, either on wall or battery power. The Attachment Daemon
> > (2.1), upsd, supports this by keeping a count of all the "active"
> > systems powered by a UPS. The count is initialised, one secondary at a
> > time by the LOGIN command, which should be understood as "count this
> > secondary as active". LOGIN is one of a trio of commands for Secondary
> > (2.9) counting: command LOGOUT (4.2.7) decrements the count and a
> > Management Daemon (2.6), upsmon, may read the count at any time using
> > command NUMLOGINS (4.2.2.3).
> >
> > The LOGIN command is also sent to the Attachment Daemon (2.1), upsd,
> > for the Primary (2.8) so during normal, fully protected operation, the
> > count is 1 (the Primary (2.8)) + the number of Secondaries (2.9).
> > During a full system shutdown, the count drops as each Secondary (2.9)
> > Management Daemon (2.6), upsmon, executes command LOGOUT (4.2.7)
> > during its own shutdown. When the count drops to 1, only the Primary
> > (2.8) is "active" and it knows that all the Secondaries (2.9) have
> > shut down.
> >
> > Is that correct?
>
> I did not look at the code but based on my experience with the
> application, your proposal sounds very good to me.
>
>
>
>
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