rc.d: add a service jails config to all base system services

This gives more permissions to services (e.g. network access to
services which require this) when they are started as an automatic
service jail.

The sshd patch is important for the sshd-related functionality as
described in the man-page in the service jails part.

The location of the added env vars is supposed to allow overriding them
in rc.conf, and to hard-disable the use of svcj for some parts where it
doesn't make sense or will not work.

Only a subset of all of the services are fully tested (I'm running this
since more than a year with various services started as service jails).
The untested parts should be most of the time ok, in some edge-cases
more permissions are needed inside the service jail.
Differential Revision: https://reviews.freebsd.org/D40371

rc.d/ldconfig: Compute ldconfig paths in a function

Move logic that computes paths passed to ldconfig(8) to a
ldconfig_paths() function that can be called for multiple ABIs.

Reviewed by: olce, kib
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D44751

rc.d/ldconfig: Remove stray ;;

Stray ";;" causes the ldconfig rc script to fail at boot. Remove it.

Fixes: 73902ed85ab7

ldconfig: only configure compat32 when kernel supports it

and eliminate hard-coded arch list.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D42669

ldconfig: filter out non-existing directories from default path

This is done only for ld-elf32.so.1, where /lib32 is kept in the path
due to the way STANDARD_LIBRARY_PATH is defined in rtld_paths.h.

This change fixes innocent warning appearing after
99132daf6f70cb0cc969c555d3612547fa3cf1db

Reviewed by: dim, emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D42626

rc.d/ldconfig: Prepend rtld stdlib paths to ldconfig(32)_paths

Ensure that ldconfig-managed elf and elf32 hints always include
the standard library paths that are known independently to rtld.

PR: 275031
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: Saltant Solutions LLC
Differential Revision: https://reviews.freebsd.org/D42557

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

ldconfig script: enable 32-bit compat on aarch64

Add aarch64 to set of architectures that support 32-bit compat
libraries.

rc.d/ldconfig: Remove mips64 check for ldconfig32.

Introduce startmsg and use it in rc scripts

startmsg is a new rc.subr(8) function function to be used instead of
echo(1) when for boot messages. It replaces the often forgotten

check_startmsgs && echo ...

with

startmsg ...

No functional change intended.

I adjusted the commit message and did some final clean-ups of the patch
before committing.

PR: 255207
Reported by: Jose Luis Duran <jlduran@gmail.com>
Reviewed by: imp, 0mp
Approved by: imp (src)
Differential Revision: https://reviews.freebsd.org/D34514

libsoft: Remove runtime ldconfig support for libsoft

Remove the runtime support for running ldconfig at boot to cache lists
of libsoft libbraries.

Sponsored by: Netflix

ldconfig: remove i386 aout invocation

aout support in ldconfig hasn't been required since FreeBSD 2.x.

Anyone still using FreeBSD 2 shared libraries can use a FreeBSD 2
ldconfig to generate aout ldconfig hints.

Reviewed by: dim, kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24883

ldconfig: fetch hw.machine_arch only once

This happens to be of significance with poudriere which runs the script a lot
when installing packages.

Move the rc framework out of sbin/init into libexec/rc.

The reasons for this are forward looking to pkgbase:
* /sbin/init is a special binary; try not to replace it with
every package update because an rc script was touched.
(a follow-up commit will make init its own package)
* having rc in its own place will allow more easy replacement
of the rc framework with alternatives, such as openrc.

Discussed with: brd (during BSDCam), kmoore
Requested by: cem, bz
PR: 231522
Approved by: re (gjb)