libprocstat(3): retrieve process command line args and environment

[Mikolaj Golub]

On Wed, Feb 20, 2013 at 09:58:02PM +0200, Mikolaj Golub wrote:
> On Wed, Feb 20, 2013 at 09:04:14AM -0500, John Baldwin wrote:
> 
> > The process should be stopped by the time we dump a core, so running it
> > multiple times should be ok in that the sizes should not change.  I would
> > say that you should try to implement a "determine sizes" pass that doesn't
> > allocate anything, but others should comment on that.
> 
> I had a little talk with kib about this recently. Kib's main concern
> looked to be that a process with many threads/open files might require
> considerable amount of kernel memory if the procstat notes are
> prepared in memory before writing. So currently I am working on
> another approach, when on the first pass the sizes are found, and on
> the second pass procstat notes are written to coredump without
> preliminarily storing all notes in memory buffer. Hope, the code won't
> look very ugly...

Here is an updated patch:

http://people.freebsd.org/~trociny/procstat_core.2.patch

- The coredump routines are modified to be able to write notes
directly to a core file, via sbuf interface, without preliminary
preparing them all in a memory buffer.

- To write NT_PROCSTAT_* notes, the corresponding sysctl routines are
changed to provide kern_proc_filedesc_out(), kern_proc_kstack_out(),
kern_proc_out(), and kern_proc_vmmap_out() functions.

- libprocstat(3) is extended to extract procstat notes from a process
core file. Also new functions (procstat_getvmmap, procstat_kstack) are
added.

- procstat(1) is changed to use libprocstat(3) where it is possible
and to treat non-numeric command line arguments as core files.

-- 
Mikolaj Golub