Opened 14 years ago

Closed 14 years ago

#711 closed defect (fixed)

SUID will not create a privileged thread for realtime video timing.

Reported by: bjm Owned by: danielk
Priority: minor Milestone: 0.19
Component: mythtv Version: head
Severity: medium Keywords:
Cc: Ticket locked: no

Description

With current Linux/glibc/etc. SUID processes are not longer allowed to create a thread with the effective userid (euid) privileges. [804X] adds VB_PLAYBACK output for mythfrontend to show the real and effective UIDs before and after the thread creation and the privileges of the thread.

2005-11-25 11:09:52.751 user: 2271 effective user: 0 before privileged thread
2005-11-25 11:09:52.752 user: 2271 effective user: 0 after privileged thread
2005-11-25 11:09:52.753 user: 2271 effective user: 2271 run_priv_thread

Change History (2)

comment:1 Changed 14 years ago by danielk

Owner: changed from Isaac Richards to danielk
Status: newassigned

I'll look at making this work with the new realtime-lsm.

comment:2 Changed 14 years ago by danielk

Resolution: fixed
Status: assignedclosed

(In [8215]) Closes #711.

Doug pointed me in the right direction on this. Linux systems that do not allow us to keep a privledged thread, allow for regular users to set the scheduler priority using either rlimits or the realtime module. I've updated the HOWTO sgml to reflect this; rlimits is the preferred way since that module made it into the Linux in 2.6.12, but some distributions supported the other contender, the realtime module. I've added a short blurb on both, plus a small paragraph on SUID for systems that don't support either of the new options.

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