On Thu, 21.05.09 14:29, interim_descriptor (interim.descriptor at gmail.com) wrote: > Hi. > > I'm trying to configure pulseaudio in Ubuntu 9.10, such that it runs as a > system instance with realtime priority, upon boot. > > I've encountered something strange. > > After running... > > chmod a+s /usr/bin/pulseaudio > > ...I would expect invoking pulseaudio would do so with root-level > permissions. And yet, here's what I get when I try that: > > id at kos-mos:~ $ pulseaudio -v > ( 0.000| 0.000) I: main.c: We're in the group 'pulse-rt', allowing > high-priority scheduling. > ( 0.000| 0.000) I: main.c: We're in the group 'pulse-rt', allowing > real-time scheduling. > ( 0.000| 0.000) I: main.c: RLIMIT_RTPRIO is set to 99, allowing > real-time scheduling. > ( 0.000| 0.000) I: main.c: RLIMIT_NICE is set to 40, allowing > high-priority scheduling. > ( 0.000| 0.000) I: core-util.c: Successfully gained nice level -11. > ( 0.000| 0.000) I: main.c: Giving up CAP_NICE > ( 0.000| 0.000) E: main.c: Root privileges required. > > > ...Am I misunderstanding what the SUID bit does, or is pulseaudio > incorrectly reporting that it doesn't have root privleges? After starting up PA will quickly drop all priviliges it gained from being SUID and become a normal user process, with the exception for scheduling related priviliges which it will keep. Please read up about difference between the UID and the EUID of a process on Unix systems. suid only changes the latter, sudo changes both. Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4
