Re: xsane requests username and password after saned has exited

From: Oliver Rauch (
Date: Mon Jun 04 2001 - 05:51:10 PDT

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    Henning Meier-Geinitz wrote:
    > Hi,
    > On Mon, Jun 04, 2001 at 09:16:53AM +0100, Nick Lamb wrote:
    > > In that case, wouldn't it be a good idea to remove all the special case
    > > code from saned which makes it commit suicide if left idle for more
    > > than a few moments?
    > >
    > > By default TCP does exactly what you want, but it seems someone has
    > > dedicated their time to undoing this facility. Perhaps they are on
    > > the list and can explain why?

    Hi Nick,

    I think the reason is if the frontend dies and does not inform saned to exit
    then saned never will exit at all.

    > If someone can write a patch and explain what it does exactly, we can
    > include it. However please don't forget other platforms, e.g. OS/2. I
    > don't want to introduce new problems before the next release.
    > As a workaround for 1.0.5: Does it help to just increase the watchdog
    > time to e.g. 30 or 60 minutes?

    Hi Henning,
    we have to decide what we have to do.
    When saned never exits when the frontend dies without calling sane_exit or sane_close
    then we need the watchdog. In this case I see two possibilities:
    1) sane-net does fork() and starts a process that sends a keep-alive package e.g. ever 60 seconds.
    2) the frontend has to initiate the keep alive package.

    A keep alive packge e.g. could be to read the option numbers (option number 0).

    The fork() in sane-net has the advantage that the network protocol works
    invisiblie for the fronten, no frontend has to care about.

    The advantage of the frontend initiated keep alive package is that we
    donīt need to create a separate keep-alive process.

    May be we could define a well_known_option "create_keepalives" that can be
    set by GUI-frontends, so for command-line-frontends the fork() is not called.



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