PERFORCE change 133090 for review

[John Birrell]

On Sat, Jan 12, 2008 at 12:35:33PM +0000, Robert Watson wrote:
> On Sat, 12 Jan 2008, John Birrell wrote:
> 
> >http://perforce.freebsd.org/chv.cgi?CH=133090
> >
> >Change 133090 by jb at jb_freebsd1 on 2008/01/12 05:00:46
> >
> >	Add a simple libproc for use by libdtrace. This is based on
> >	ptrace, kevent and kvm instead of procfs like the one in Solaris.
> 
> Does it actually depend on kvm (/dev/kmem) or just on libkvm interfaces? 
> We've been trying to eliminate dependence on /dev/kmem for tools that 
> otherwise don't require privilege over the last few years, in the interests 
> of eliminating setgid kmem.  Generally, we've done this by adding sysctls 
> that explicitly export the required information, and in some cases, those 
> sysctls have been wrapped by existing libkvm interfaces.  I guess this is 
> most easily answered by knowing if things using libdtrace->libproc require 
> setgid to operate :-).

I started using the process status via kvm, but found that it was better
obtained as a kevent, so the code at the moment doesn't do anything via
kvm. I can probably complete the functionality via the ptrace() call and
remove the libkvm stuff altogether.

--
John Birrell