Bugtraq mailing list archives
Re: x11amp playlist bug
From: sailer () IFE EE ETHZ CH (Thomas Sailer)
Date: Thu, 5 Mar 1998 09:13:09 +0100
Ari Heitner wrote:
I installed x11amp w/o making it setuid, it's perms are -rwxr-xr-x 1 root root 623456 Feb 23 13:33 x11amp* it works very nicely. I don't know why the x11amp people would recommend setuiding it to root, except that this may avoid access problems writing to /dev/dsp.
I don't know x11amp (yet), but the soundcard access code I put into amp uses root privs to mlock itself into memory and set itself (sched_setscheduler(SCHED_RR)) to rt prio. That way, I can get away with very low buffer space and I can stuff the decoded samples directly into the DMA buffer of the soundcard. This makes it possible to run AMP on a heavily loaded machine without audible effects. I think there's a fallback to the old code that just uses a rather big audio buffer between the decoder and the sound driver. Obviously, this won't work well on a heavily loaded machine. Tom NB: I thought I have been rather careful in giving up root perms as soon as possible, but maybe I've missed something...
Current thread:
- Re: x11amp playlist bug Ari Heitner (Feb 28)
- <Possible follow-ups>
- Re: x11amp playlist bug root (Mar 02)
- Re: x11amp playlist bug Tim Newsham (Mar 03)
- Re: x11amp playlist bug Thomas Sailer (Mar 05)