MFC r335939, r336088:
Add setproctitle_fast(3) for frequent callers.

MFC r309006: remove unnecessary vm includes from setproctitle

vm headers were needed only for the PS_STRINGS fallback, which was
removed in r297888.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

libc: do not include <sys/types.h> where <sys/param.h> was already included

According to style(9):
> normally, include <sys/types.h> OR <sys/param.h>, but not both.
(<sys/param.h> already includes <sys/types.h> when LOCORE is not defined).

Remove PS_STRINGS fallback from setproctitle

In r103767 the kern.ps_strings sysctl was added as the preferred way to
locate the ps_strings struct and is available in any FreeBSD release
supported within the last decade.

Reviewed by: kib

Remove code to support the top of the stack layout for FreeBSD 1.x/2.x
kernel, but keep explanation of the old ps_strings structure to make
it clear what sanity check tries to accomplish.

Noted by: Oliver Pinter <oliver.pinter@hardenedbsd.org>
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

Don't segfault if setproctitle(3) is called with NULL initially.
The old buffer was not being initialized and a later str*() op on
it would cause a crash if it wasn't initialized by a previous
call to setproctitle(3) with an actual string.

Noticed by: Ashley Penney <ashp@unloved.org>

Reduce libc's memory footprint by lazily allocating memory used internally
by setproctitle().

Reviewed by: jkh

Do not use __progname directly (except in [gs]etprogname(3)).
Also, make an internal _getprogname() that is used only inside
libc. For libc, getprogname(3) is a weak symbol in case a
function of the same name is defined in userland.

Fix SCM ID's.

When recording the original arguments, stop short if we encounter
a NULL argument. Some programs change the contents of the argv
array, typically to remove some special arguments. They shorten
argv by storing a NULL where an argument pointer used to be. Such
programs core dumped if they called setproctitle(), because it
would try to apply strlen() to a NULL pointer.

When recording the original arguments, don't (ab)use "nargc" for
iterating over the arguments. Doing so wipes out the value which
is about to be stored into the ps_strings structure.

If the format string passed to setproctitle begins with a '-'
character, skip the program name when setting the process title.
Ansified with extreme prejudice.

Reviewed by: peter

Make setproctitle(NULL) restore all of the original arguments
(if it's able).

Introduce commandline caching in the kernel.

This fixes some nasty procfs problems for SMP, makes ps(1) run much faster,
and makes ps(1) even less dependent on /proc which will aid chroot and
jails alike.

To disable this facility and revert to previous behaviour:
sysctl -w kern.ps_arg_cache_limit=0

For full details see the current@FreeBSD.org mail-archives.

$Id$ -> $FreeBSD$

Adjust for kern.ps_strings and PS_STRINGS not being a pointer. This is
an unimprovement here. I thought it would be an improvement, as in libkvm,
but here we can access the strings directly.

Use sysctlbyname() instead of sysctl() and trust it to give a nonzero
address if it succeeds.

Oops, revert part of a diff that wasn't supposed to have been committed.

Cache the results of the ps_strings sysctl so that it doesn't have to be
redone for every call of setproctitle().

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

General -Wall warning cleanup, part I.
Submitted-By: Kent Vander Velden <graphix@iastate.edu>

If the two recently added sysctl variables exist, use those rather than
the statically compiled PS_STRINGS and USRSTACK variables. This prevents
programs using setproctitle from coredumping if the kernel VM is increased,
and stops libkvm users (w, ps, etc) from needing to be recompiled if only
the VM layout changes.

Bring in an initial version of setproctitle().. This is intended to
replace the dozen other various hacks in the code that do all sorts
of crude things including spamming the envrionment strings with the new
argv string.

This version is mainly inspired by the sendmail version, with a couple of
ideas taken from the NetBSD implementation as well.