rainbow and pam

[Albert Cahalan]

Jim Gettys writes:

> Victor needs some way to be able to set the real time features
> of Linux; this is certainly desirable in various audio, voip
> and similar applications.

Quick fix: eliminate the restriction in the kernel

While this causes obvious problems for shared multi-user
machines, it doesn't really cause problems for the laptop.
Activities that abuse the ability, and thus force the user
to reboot via power loss, will naturally be unpopular.

Proper fix: make the kernel have a per-task inheritable upper
limit on the real-time priority. Perhaps the existing limit
(used for niceness) can even do the job. It's this thing:

current->signal->rlim[RLIMIT_NICE]