[mythtv-users] CTRL-ALT-BACKSPACE

[Allen Edwards]

On Sat, Mar 9, 2019 at 6:39 PM Stephen Worthington <stephen_agent at jsw.gen.nz>
wrote:

> On Sat, 9 Mar 2019 14:17:50 -0800, you wrote:
>
> >On Sat, Mar 9, 2019 at 1:20 PM Allen Edwards <allen.p.edwards at gmail.com>
> >wrote:
> >
> >>
> >>
> >> On Fri, Mar 8, 2019 at 6:57 PM Stephen Worthington <
> >> stephen_agent at jsw.gen.nz> wrote:
> >>
> >>> One alternative is to use lirc to assign a button on your remote to
> >>> kill mythfrontend.real.  Lirc can be set up to run scripts using
> >>> irexec.  The script would do a ps -e and find any running copies of
> >>> mythbackend.real and kill them.  Then the mythfrontend script would
> >>> see that mythfrontend.real had died and would restart it.
> >>>
> >>
> >>
> >Stephen
> >I have tried this without success.  Here is what I did.
> >1) I modified a key config action to escape
> >2) I verified that the key was now the escape key
> >3) I  modified the same key definition to run irexec and changed the
> config
> >action to "killall mythfrontend.real"
> >4) The key did nothing. Myth did not close and the pid did not change
> >5) I copied the config action to a terminal and it killed mythfrontend
> >
> >By the way, myth does not restart when I kill it.
> >
> >This is not exactly what you told me to do but it seemed like it should
> >work.
>
> >Correction: What I did was verify that I could change a key and test it,
> >then put an action that I verified would kill mythfrontend in and set the
> >key to irexec. Didn't do anything.
>
> Lirc runs irexec, not a key setting in MythTV.  In /home/<mythfrontend
> user>, you should find a file .lircrc that looks something like this:
>
> root at mypvr:/home/stephen# cat .lircrc
> #Custom lircrc generated via mythbuntu-lirc-generator
> #All application specific lircrc files are within ~/.lirc
> include ~/.lirc/mythtv
> include ~/.lirc/mplayer
> include ~/.lirc/xine
> include ~/.lirc/vlc
> include ~/.lirc/xmame
> include ~/.lirc/xmess
> include ~/.lirc/totem
> include ~/.lirc/elisa
> include ~/.lirc/irexec
>
> That is the file that lirc loads by default to set up all its
> keystrokes.  By convention, a separate file is used for the setup for
> each program that uses lirc, but the actual specification of the
> programs is done on the "prog =" lines inside those files, so you can
> mix setting for different programs in one lirc config file if you
> like.  My remote is using the devinput driver, so for a lirc key
> config to do anything, it needs a "remote = devinput" line.  Here are
> the first three key configs in my /home/stephen/.lirc/mythtv file:
>
> begin
>     remote = devinput
>     prog = mythtv
>              # Guide key
>     button = KEY_EPG
> #    config = S
>     config = Ctrl+Alt+G
>     repeat = 0
>     delay = 0
> end
>
> begin
>     remote = devinput
>     prog = mythtv
>     button = KEY_EXIT
>     config = Escape
>     repeat = 0
>     delay = 0
> end
>
> begin
>     remote = devinput
>     prog = mythtv
>     button = KEY_OK
>     config = Return
>     repeat = 0
>     delay = 0
> end
>
> begin
>     remote = devinput
>     prog = mythtv
>     button = KEY_RIGHT
>     config = Right
>     repeat = 1
>     delay = 1
> end
>
> So what the first one of those does is to say that when lirc receives
> a KEY_EPG input from the devinput driver, then if the program with the
> lirc name "mythtv" is attached to lirc at the time, it should send a
> Ctrl-Alt-G keystroke to that program.  Then inside mythfrontend (which
> is running with the lirc name "mythtv"), it will receive the
> Ctrl-Alt-G keystroke, look up its keystroke configs from the database
> and see that (in my setup) it should jump directly to the Programme
> Guide:
>
> MariaDB [mythconverg]> select * from jumppoints where keylist like
> '%alt+g%';
> +---------------+-------------+------------+----------+
> | destination   | description | keylist    | hostname |
> +---------------+-------------+------------+----------+
> | Program Guide | NULL        | Ctrl+Alt+G | mypvr    |
> +---------------+-------------+------------+----------+
> 1 row in set (0.00 sec)
>
>
> Here is an example with irexec:
>
> begin
>     remote = devinput
>     prog = irexec
>     button = KEY_YELLOW
>     config = echo "This is the Yellow key"
>     repeat = 0
>     delay = 0
> end
>
> What that does is when a KEY_YELLOW (teletext key) keystroke is
> received from the devinput driver, then if irexec is running and
> attached to lirc, then send irexec the keys in the "config =" line. So
> irexec will receive a line of text containing the echo command, which
> it will then execute.  For this to do anything, you need to be running
> irexec in the background as the same user that mythfrontend runs from.
> I think you said you are running Ubuntu 16.04, so the best way to run
> irexxec there is from systemd.  But the lirc package in 16.04 does not
> set that up for you.  In 18.04 the package installs a
> /lib/systemd/system/irexec.service file for you to modify to make this
> work:
>
> root at mypvr:/lib/systemd/system# cat irexec.service
> [Unit]
> Documentation=man:irexec(1)
> Documentation=http://lirc.org/html/configure.html
> Documentation=http://lirc.org/html/configure.html#lircrc_format
> Description=Handle events from IR remotes decoded by lircd(8)
>
> [Service]
> ; user=lirc
> ; group=lirc
>
> ; Hardening opts, see systemd.exec(5).  Doesn't add much unless
> ; not running as root. If these are applicable or not depends on
> ; what commands irexec.lircrc invokes.
> ;
> ; NoNewPrivileges=true
> ; MemoryDenyWriteExecute=true
> ; PrivateTmp=true
> ; ProtectHome=true
> ; ProtectSystem=full
>
>
> Type=simple
> ExecStart=/usr/bin/irexec /etc/lirc/irexec.lircrc
>
> [Install]
> WantedBy=multi-user.target
>
> So what you need to do is to install an irexec.service file for your
> system.  The easy way to do that now (as long as the 16.04 systemd
> version is late enough, which I think it is), is to run this command:
>
> sudo systemctl --full edit irexec.service
>
> I have never used the --full option before, so I do not know what it
> will do if the original irexec.service file is not present, so if you
> get an error with that command, remove the --full option.  The command
> should open your default system editor with the correct irexec.service
> file open, which should be empty in your case.  Paste in this text
> with the name of your mythfrontend user subsituted in two places:
>
> [Unit]
> Documentation=man:irexec(1)
> Documentation=http://lirc.org/html/configure.html
> Documentation=http://lirc.org/html/configure.html#lircrc_format
> Description=Handle events from IR remotes decoded by lircd(8)
>
> [Service]
> user=<your mythfronted user>
> group=mythtv
>
> ; Hardening opts, see systemd.exec(5).  Doesn't add much unless
> ; not running as root. If these are applicable or not depends on
> ; what commands irexec.lircrc invokes.
> ;
> ; NoNewPrivileges=true
> ; MemoryDenyWriteExecute=true
> ; PrivateTmp=true
> ; ProtectHome=true
> ; ProtectSystem=full
>
>
> Type=simple
> ExecStart=/usr/bin/irexec /home/<your mythfrontend user>/.lirc/irexec
>
> [Install]
> WantedBy=multi-user.target
>
> Save that and exit from the editor.  Then run these commands:
>
> sudo systemctl enable irexec.service
> sudo systemctl start irexec.service
> sudo systemctl status irexec.service
>
> The status command should show irexec has started and is running.  If
> that has not worked, then you will need to fix whatever errors the log
> output shows.
>
> Then you can edit the /home/<your mythfrontend user>/.lirc/irexec file
> to put in the commands you want to be able to run from remote buttons.
> Each time you change that file, you need to do this command to restart
> irexec so it re-reads the config file:
>
> sudo systemctl restart irexec.service
>
> If you want to save a little typing, ".service" is what systemctl
> defaults to if the unit type is left off, so you can shorten the
> systemctl commands like this:
>
> sudo systemctl restart irexec
>
> To test if irexec is working properly, set it up with a echo command
> like my example, then open a terminal on X and press the remote button
> to execute the irexec echo command.  You should see the echo text
> appear in the terminal window.  Once that is working, you can try the
> "killall mythfrontend.real" command.
>
> The last time I have actually used irexec like this was in 14.04, so I
> have never actually tested the above setup via systemd.  So there
> could be a bug or two.
> _______________________________________________
>

Thanks Stemphen for the detailed explanation.  I see now that the edit I
did is not working because the users are different. I also see I would need
to make quite a few modifications. Seeing all that and your last sentence I
think I will focus on getting Myth to startup without adding instances of
itself every time there is a restart. I spent most of today trying to
figure that out. I have a lead from Ian but don't know what starts myth so
can't go further.  I found a shell script that looks like it would start it
but it is from 2007 so I am dubious.

This thread has forked and I guess that is my fault. The fork has a
different subject line so it should be pretty clear.  Did you see that if I
do CTRL-ALT-BS 10 times I got 9 instances of mythfrontend running? Whatever
is starting myth is not noticing that it is already running.

Allen
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