MFC r309676

Export the whole thread name in kinfo_proc

kinfo_proc::ki_tdname is three characters shorter than
thread::td_name. Add a ki_moretdname field for these three
extra characters. Add the new field to kinfo_proc32, as well.
Update all in-tree consumers to read the new field and assemble
the full name, except for lldb's HostThreadFreeBSD.cpp, which
I will handle separately. Bump __FreeBSD_version.

Sponsored by: Dell EMC

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Use procstat_getkstack(3) for retrieving process kernel stacks
instead of direct sysctl calls.

MFC after: 1 month

Rename ki_ocomm to ki_tdname and OCOMMLEN to TDNAMLEN.
Provide backward compatibility defines under BURN_BRIDGES.

Suggested by: jhb
Reviewed by: emaste
Sponsored by: Sandvine Incorporated
Approved by: re (kib)

- Commit work from libprocstat project. These patches add support for runtime
file and processes information retrieval from the running kernel via sysctl
in the form of new library, libprocstat. The library also supports KVM backend
for analyzing memory crash dumps. Both procstat(1) and fstat(1) utilities have
been modified to take advantage of the library (as the bonus point the fstat(1)
utility no longer need superuser privileges to operate), and the procstat(1)
utility is now able to display information from memory dumps as well.

The newly introduced fuser(1) utility also uses this library and able to operate
via sysctl and kvm backends.

The library is by no means complete (e.g. KVM backend is missing vnode name
resolution routines, and there're no manpages for the library itself) so I
plan to improve it further. I'm commiting it so it will get wider exposure
and review.

We won't be able to MFC this work as it relies on changes in HEAD, which
was introduced some time ago, that break kernel ABI. OTOH we may be able
to merge the library with KVM backend if we really need it there.

Discussed with: rwatson

Include param.h instead of types.h before user.h so that the nested
include of param.h can be removed from audit.h.

MFC after: 3 weeks

WARNS fixes: mainly constness and avoid comparing signed with
unsigned by making array indicies unsigned. Also note one or two
unused parameters.

Display per-thread command line in TDNAME field for -k and -t; if
no per-thread name is available or the name is identical to the
process name, display "-" instead. Very slightly shrink the COMM
entry to make a bit more room, although this doesn't help with
stack traces much.

Suggested by: thompsa

Add procstat(1), a process inspection utility. This provides both some
of the missing functionality from procfs(4) and new functionality for
monitoring and debugging specific processes. procstat(1) operates in
the following modes:

-b Display binary information for the process.
-c Display command line arguments for the process.
-f Display file descriptor information for the process.
-k Display the stacks of kernel threads in the process.
-s Display security credential information for the process.
-t Display thread information for the process.
-v Display virtual memory mappings for the process.

Further revision and modes are expected.

Testing, ideas, etc: cognet, sam, Skip Ford <skip at menantico dot com>
Wesley Shields <wxs at atarininja dot org>