Re: BUG: Log on Scheduled Task invisible/empty window blocks input

[Ross Patterson <me@rpatterson.net>]

> dash (or bash if required) native path with WD /var/log/ native path e.g.
>
> %CYGWIN_ROOT%\bin\dash /usr/local/bin/....sh WD %CYGWIN_ROOT%\var\log

I'm not understanding the use of `WD` here, can you clarify/elaborate?

At any rate, I forgot to mention that I also tried adding output
redirection to the end of the action's ""Add arguments (optional)" and
did so in various combination with the other variants described in my
OP:

    ... >> C:\...\log\....log 2>&1

And I observed the same or similar mix of different blocking window types.

> For normal scripts and schedules, I use cron job commands or scripts which log
> everything under /var/log/.

In that case, I'd still need `# crond` to run with highest privileges
as those are the privileges I ultimately need what it would run to
have.  But maybe I'll try that if I get time to do more testing.

Have you tested the first, most simple, test case from my OP?  It's a
very elemental test and reproduces the issue reliably for me so it
would be interesting to hear what you (or anyone else) observes from
that test case.

Note that the totally invisible/transparent version of the blocking
window is only observable by an area of the display that doesn't
respond to mouse inputs.  Also note that if your display resolution is
high enough, or scaling settings accomplish the same, you need to be
able to look for blocked mouse input all over your screen.  In my case
where it's a 10-foot UI, the default window size blocks most of the
display which makes finding blocked mouse input easy.  I also find it
easiest to test for the presence of the blocking window with something
that responds to mouse over inputs with a clear visual signal across
the whole display, Kodi in my case.

Ross

On Fri, Jan 27, 2023 at 11:39 AM Brian Inglis via Cygwin
<cygwin@cygwin.com> wrote:
>
> On 2023-01-26 19:43, Ross Patterson via Cygwin wrote:
> > TL;DR: I needed to run a Cygwin process at user log on with highest
> > privileges to perform some operations that are not allowed any other
> > way without requiring a UAC prompt.  This results in a window without
> > any border, close button or any other decoration that is most often
> > invisible/transparent, sometimes opaque white, and most rarely with
> > black unusable left/bottom scroll bars.  The window is always on top,
> > accepts no inputs at all, and blocks input to windows below.  The only
> > way to get rid of the windows is to kill the scheduled task process or
> > trigger a UAC prompt.  More details below.
> >
> > It seems like this probably is a bug, so feel free to consider this a
> > bug report, but I'm mostly writing this up so others can find it and
> > my workarounds and hopefully save them some hassle and I probably
> > won't be doing much followup.  Both the edge cases and observed
> > results are numerous and each test iteration is time consuming, but
> > I've done my best to get as complete coverage as I could and to
> > tightly control conditions for reliable results.
> >
> > There are a few things I want to do through Cygwin that require
> > privileges that cannot be attained through a service or a scheduled
> > task with an "At startup" trigger.  The only way I've found to run the
> > process with the required privileges without a UAC prompt and without
> > disabling UAC completely is a scheduled task with these settings:
> >
> > 1. "General" tab: "Run only when user is logged on" = SELECTED
> > 2. "General" tab: "Run with highest priveleges" = CHECKED
> > 3. "Triggers" tab: Add an "At log on" trigger for a "Specific user"
> >
> > As such I've not tested this behavior with different settings on the
> > "General" tab.
>
> I use scheduled tasks with actions running scripts from /usr/local/bin/ under
> dash (or bash if required) native path with WD /var/log/ native path e.g.
>
> %CYGWIN_ROOT%\bin\dash /usr/local/bin/....sh WD %CYGWIN_ROOT%\var\log
>
> with various options (mainly user SYSTEM, logged in or not, highest privileges),
> and triggers.
>
> I never see any windows appearing as the scripts log everything under /var/log/.
>
> The scripts run as tasks start and stop Cygwin services, init and run smart
> reporting, clean up cron job remnants before smart reporting, terminate all
> processes before running setup.
>
> For normal scripts and schedules, I use cron job commands or scripts which log
> everything under /var/log/.
>
> --
> Take care. Thanks, Brian Inglis                 Calgary, Alberta, Canada
>
> La perfection est atteinte                      Perfection is achieved
> non pas lorsqu'il n'y a plus rien à ajouter     not when there is no more to add
> mais lorsqu'il n'y a plus rien à retirer        but when there is no more to cut
>                         -- Antoine de Saint-Exupéry
>
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