[mythtv-users] Real time threads and FC3

[Chris Trown]

Jonathan Tidmore wrote:
>  >From what I can tell, setuid to root (chmod u+s /usr/bin/mythfrontend) 
> doesn't work on mythfrontend due to some sort of bug.  The only way I 
> got it to work is to use sudo to start mythfrontend. 
> 
> To use sudo to start mythfrontend and use realtime priority.  I have 
> user mythtv running X and mythtv owns all video/tv files so I need to 
> give sudo rights to user mythtv to start mythfrontend.
> 
> To do so:
> 
>    1. run 'visudo' as root
>    2. Under Cmnd alias specification, enter 'Cmnd_Alias MFE =
>       /usr/bin/mythfrontend'
>    3. Under User privilege specification, enter 'mythtv  ALL=(ALL)
>       NOPASSWD: MFE'
>    4. Exit visudo using the vi save and exit command, :wq
>    5. You're /etc/sudoers file (NEVER edit /etc/sudoers directly, use
>       'visudo') should look something like:
> 
> # Cmnd alias specification
> Cmnd_Alias MFE = /usr/bin/mythfrontend
> 
> # Defaults specification
> 
> # Runas alias specification
> 
> # User privilege specification
> root    ALL=(ALL) ALL
> mythtv  ALL=(ALL) NOPASSWD: MFE
> 
> 
> Start mythfrontend using the command: e.g. '/usr/bin/sudo 
> /usr/bin/mythfrontend &'  The frontend is now running as root.    You 
> should see a log entry that says something like 'Using realtime 
> priority' when you start mythfrontend.  Warning, this may or may not 
> violate your security standards and should only do so if you understand 
> the risks involved running an application as root.
> 

      Thanks for replying.

      I know the risks and that's precisely why I don't want to have the 
thing run as root.  If it can be done without root privs, I'd rather do 
that.

      When I run mythfrontend as root, I do see the message.

      I'd like to know if it is possible, with FC3, to get realtime 
priority threads using PAM.  Everything I've read says it's possible, 
however...

      This is on a system running the latest updates and kernel for FC3, 
btw.

Chris...

> 
> 
> On 11/22/05, *Chris Trown* <ctrown at safe-mail.net 
> <mailto:ctrown at safe-mail.net>> wrote:
> 
> 
>           I've been battling image problems with my install and thought that
>     the problem was lack of priority for the mythfrontend in the kernel.
>     Turns out that's not the problem, but I still would like to know.
> 
>           Has anyone managed to get realtime priority threads working with
>     Fedora Core3?
> 
>           I've read the following thread and tried it all out:
> 
>     http://www.gossamer-threads.com/lists/mythtv/users/159201?search_string=rtprio;#159201
> 
>           But it doesn't work.  I've read some posts out on the 'Net saying
>     that rtprio has been included in the latest PAM for FC3, but the dox
>     I've seen doesn't list that as an option.  I also went as far as to D/L
>     the SRPM for PAM to tkae a look.  I grep'd the entire tree looking for
>     "rtprio".  No joy.
> 
>           So anybody get this working?
> 
>     Chris...
> 

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