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Realtime priority http://forum.linhes.org/viewtopic.php?f=3&t=8085 |
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Author: | bobmyth [ Tue Jan 24, 2006 9:48 pm ] |
Post subject: | Realtime priority |
My current myth system is a bit under powered to play back HDTV. To address this, I've started using the "Realtime priority" feature in the front end. I found a good posting about this: http://mythtv.org/pipermail/mythtv-users/2005-June/090868.html I tried to set my frontend as SUID root, but I wasn't able to get the realtime priority to work. So, I had to add the frontend to sudo: 1. Edit (as root) /etc/sudoers 2. Add /usr/bin/mythfrontend to the last line in the file Be warned: there are security implications to doing this. I have also noticed that some files are created and are owned by root instead of mythtv. To get your frontend to start using sudo: 1. Edit (as root) /usr/local/bin/KnoppMyth-run 2. Change line 15 from this: Code: exec mythfrontend to this: Code: exec sudo mythfrontend
Anyone else have better ideas? |
Author: | cesman [ Tue Jan 24, 2006 11:44 pm ] |
Post subject: | |
Wait for the next release which does this via PAM... How is that for an idea? |
Author: | bobmyth [ Wed Jan 25, 2006 9:11 pm ] |
Post subject: | |
Looks like the next release will do it using PAM, can't wait. |
Author: | sammo2828 [ Mon Feb 20, 2006 10:51 pm ] |
Post subject: | |
Is there any reason why setuid doesn't work? |
Author: | tjc [ Mon Feb 20, 2006 10:56 pm ] |
Post subject: | |
Because then it runs as root and a lot of stuff ends up either ends up owned by root or in odd places... |
Author: | sammo2828 [ Tue Feb 21, 2006 12:04 am ] |
Post subject: | |
Yah, I understand that running mythfrontend as root means that some files end up being owned by root or in odd places. My question is, why does setuid root (chmod ug+s /usr/bin/mythfrontend) not work? Why do you have to use sudo? Thanks |
Author: | sammo2828 [ Tue Feb 21, 2006 6:11 pm ] |
Post subject: | |
cesman wrote: Wait for the next release which does this via PAM... How is that for an idea?
The mythtv docs say you need Linux 2.6.12 or newer and PAM 0.79 or newer. I am running Linux 2.6.13, and just upgraded PAM with: apt-get update apt-get install libpam-modules libpam-runtime libpam0g dpkg -l |grep libpam ii libpam-modules 0.79-3.1 Pluggable Authentication Modules for PAM ii libpam-runtime 0.79-3.1 Runtime support for the PAM library ii libpam0g 0.79-3.1 Pluggable Authentication Modules library Added the following lines to /etc/security/limits.conf @mythtv - rtprio 50 @mythtv - nice 0 Rebooted Still getting "Realtime priority would require SUID as root." in mythfrontend log Any tips on what I'm missing out on? |
Author: | cesman [ Tue Feb 21, 2006 6:29 pm ] |
Post subject: | |
Per the docs, you need Quote: * - rtprio 0 Do you have the first two lines?
* - nice 0 @audio - rtprio 50 @audio - nice 0 |
Author: | sammo2828 [ Tue Feb 21, 2006 6:45 pm ] |
Post subject: | |
yah, sorry, i have the first two lines too ... and @mythtv instead of @audio Do I need to try this patch:?? http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=313588 http://ubuntustudio.com/wiki/index.php/ ... -Aware_PAM |
Author: | cesman [ Tue Feb 21, 2006 6:54 pm ] |
Post subject: | |
Perhaps. Please do try it and let me know as I too followed the directions in the MythTV docs. |
Author: | sammo2828 [ Tue Feb 21, 2006 7:00 pm ] |
Post subject: | |
okay, followed the instructions to download pam source, patch, rebuild and install ... rebooted and success! Using realtime priority. |
Author: | cecil [ Wed Feb 22, 2006 5:44 am ] |
Post subject: | |
Perhaps providing greater details, steps, etc. |
Author: | sammo2828 [ Wed Feb 22, 2006 6:18 am ] |
Post subject: | |
yo... just followed the instructions to patch PAM at http://ubuntustudio.com/wiki/index.php/ ... -Aware_PAM here's exactly what i did: started with R5A12, mythtv 0.19, kernel 2.6.13 Code: apt-get update apt-get install libpam-modules libpam-runtime libpam0g (above step probably doesn't make a difference because i ended up patching the package and reinstalling in a later step) add the following lines to /etc/security/limits.conf: Code: * - rtprio 0 * - nice 0 @mythtv - rtprio 50 @mythtv - nice 0 (now this is the hardest part) Code: su (enter password) Code: apt-get install pbuilder vi /etc/pbuilderrc (change mirror to closest site MIRRORSITE=http://ftp.au.debian.org/debian) Code: pbuilder create (wait for about an hour, cos it took ages downloading some stuff) Code: exit (get out of root) Code: mkdir /tmp/pam cd /tmp/pam apt-get source pam wget http://librarian.launchpad.net/1510182/pam-rtlimits.patch mv pam-rtlimits.patch pam-0.79/debian/patches-applied/070_pam_rlimit_rtprio.patch cat > pam-0.79/debian/patches-applied/071_pam_rlimit_rtprio_defines.patch << "EOF" --- Linux-PAM-0.79/modules/pam_limits/pam_limits.c-orig +++ Linux-PAM-0.79/modules/pam_limits/pam_limits.c @@ -34,6 +34,11 @@ #include <sys/types.h> #include <sys/stat.h> #include <sys/resource.h> +/* hack: glibc-2.3.6 doesn't yet know about these yet */ +#define RLIMIT_NICE 13 +#define RLIMIT_RTPRIO 14 +#undef RLIM_NLIMITS +#define RLIM_NLIMITS 15 #include <utmp.h> #ifndef UT_USER /* some systems have ut_name instead of ut_user */ EOF cd pam-0.79/Linux-PAM/ patch -p2 < ../debian/patches-applied/070_pam_rlimit_rtprio.patch patch -p1 < ../debian/patches-applied/071_pam_rlimit_rtprio_defines.patch cd ../.. (edit pam-0.79/debian/changelog and add a changelog entry at top): Code: pam (0.79-3ubuntu7rtprio1) dapper; urgency=low * Linux-PAM/modules/pam_limits/pam_limits.c: add support for rtprio (RLIMIT_RTPRIO) and nice (RLIMIT_NICE). Closes: debian #326555, ubuntu #17348. -- Wolfgang Hoffmann <woho@woho.de> Sat, 4 Feb 2006 20:01:00 +0100 Code: dpkg-source -b pam-0.79/ pam_0.79.orig.tar.gz su (enter root password again) Code: pbuilder build pam_0.79-3ubuntu7rtprio1.dsc (takes a while, half an hour or more???) Code: dpkg -i /var/cache/pbuilder/result/libpam*3ubuntu7rtprio1*.deb (this installs the new package) Code: reboot ******************** exit out of mythfrontend start xterm (alt-x) Code: mythfrontend -l blah.txt -v playback (goto recorded playback or watchtv and play something) (go back to xterm with alt-tab) Code: less blah.txt
/realtime (search for realtime and you will see it is working sucessfully .. yippeeeeeee!) |
Author: | cesman [ Thu Feb 23, 2006 3:52 am ] |
Post subject: | |
Cool! Thanks for contributing. |
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