MFC freebsd-update: unconditionally regenerate passwd/login.conf files

The existing logic is nice in theory, but in practice freebsd-update will
not preserve the timestamps on these files. When doing a major upgrade, e.g.
from 12.1-RELEASE -> 12.2-RELEASE, pwd.mkdb et al. appear in the INDEX and
we clobber the timestamp several times in the process of packaging up the
existing system into /var/db/freebsd-update/files and extracting for
comparisons. This leads to these files not getting regenerated when they're
most likely to be needed.

Measures could be taken to preserve timestamps, but it's unclear whether
the complexity and overhead of doing so is really outweighed by the marginal
benefit.

I observed this issue when pkg subsequently failed to install a package that
wanted to add a user, claiming that the user was removed in the process.
bapt@ pointed to this pre-existing bug with freebsd-update as the cause.

PR: 234014, 232921

(cherry picked from commit ebebc41e4cfe44b8e8fd881badf2fa2c4be65aa4)

Git Hash: cd7da1deb581122c94c3735b78fafdd04ce77b67
Git Author: kevans@FreeBSD.org

MFC r364396: Unbreak `freebsd-update updatesready'.

The command would only work if PWD happened to be WORKDIR.
Also, exit 1 in case WORKDIR exists, but isn't accessible
by the current user.

PR: 242709
Reported by: Max Fiedler

MFC r360287: freebsd-update: rehash certs

With the inclusion of caroot bits, we'll need to also rehash on update as we
do in mergemaster/etcupdate.

If certctl's installed on the system, just unconditionally rehash. This
isn't an expensive operation, and we can refine it to compare
INDEX-{OLD,NEW} later if we really want to.

MFC r352513, r352514, r352662:

As suggested by koobs, MFC recent freebsd-update changes to
have a consistent user experience on all supported
versions.

r352513:
freebsd-update.8: appease igor

igor follows American style guides in the belief that abbreviations i.e.
and e.g. are always followed by a comma. Make that change now so that
future updates to freebsd-update.8 do not complain about this.

r352514:
freebsd-update: make usage output consistent

Drop trailing . which appeared only on description of IDS.

r352662:
freebsd-update: Add `updatesready' and `showconfig' commands

`freebsd-update updatesready' can be used to check if there are any pending
fetched updates that can be installed.

`freebsd-update showconfig' writes freebsd-update's configuration to
stdout.

This also changes the exit code of `freebsd-update install' to 2 in case
there are no updates pending to be installed and there wasn't a fetch phase
in the same invocation. This allows scripts to tell apart these error
conditions without breaking existing jail managers.

PR: 240757, 240177, 229346
Reviewed by: manpages (bcr), secteam (emaste), yuripv
Differential Revision: https://reviews.freebsd.org/D21473

MFC r352542: freebsd-update: Fix src component detection

PR: 224048, 238558, 23999
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D21579

MFC r344280: freebsd-update: Clarify help text

Improve help text to include example release numbers for reference
and clarify the -F option.

PR: 231185, 214619
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reviewed by: delphij, rgrimes
Sponsored by: The FreeBSD Foundation

MFC r34505: freebsd-update: restore old exit code when no updates are available
locally

This unbreaks ezjail and iocell, which get into an endless loop trying to
figure out how many times "freebsd-update install" needs to be called.

PR: 229346
Submitted by: Mike Cole <mcole36 at gmail.com>
Approved by: bapt

MFC freebsd-update: Clarify unsupported release upgrade error message

MFC r343122:

freebsd-update: Clarify unsupported release upgrade error message

Notify users that upgrading from -CURRENT or -STABLE is unsupported by
freebsd-update.

Also ensure --currently-running provides a correctly formatted release
(as done by -r).

Reported by: yuri
Reviewed by: bcran

MFC r343268:

frebsd-update: fix --currently-running after r343122

Reported by: Brandon Schneider

MFC r343271:

freebsd-update: Allow upgrade from pre-release builds

Update r343122 to include -ALPHA, -BETA and -RC releases as
upgrade-able via freebsd-update.

Reported by: delphij, des
Reviewed by: delphij

MFC r343410:

freebsd-update: fix style from r343271 change

PR: 234771
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Sponsored by: The FreeBSD Foundation

freebsd-update: Use BASEDIR when checking for src componentfreebsd-update: Use BMFC r343152: freebsd-update: Use BASEDIR when checking for src component

src could potentially be installed under the based dir
and not under the root or vice versa.

PR: 224048
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reviewed by: delphij
Sponsored by: The FreeBSD Foundation

MFC r343270: freebsd-update: Update /etc/passwd after password db changes

Add -p to pwd_mkdb in order to ensure password db changes are also
included in /etc/passwd.

PR: 165954, 232921, 229487
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reviewed by: jilles
Sponsored by: The FreeBSD Foundation

MFC r343411: freebsd-update: Clarify unsupported upgrade message

PR: 204115
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reviewed by: delphij
Sponsored by: The FreeBSD Foundation

MFC r343412: Fix a typo/wordsmith a description modified in [MFC of r343407]

MFC r343407: freebsd-update: open $PAGER only if necessary

PR: 194547, 208497
Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reviewed by: delphij
Sponsored by: The FreeBSD Foundation

MFC r343409: freebsd-update: Stop installing empty component sets

Submitted by: Gerald Aryeetey <aryeeteygerald_rogers.com>
Reported by: rgrimes
Reviewed by: delphij
Sponsored by: The FreeBSD Foundation

MFC r343589: freebsd-update: regenerate man page database after update

These are currently not reproducible because they're built by the
makewhatis on the freebsd-update build host, not the one in the tree.
Regenerate after update, and later we can avoid including it in
freebsd-update data.

PR: 214545, 217389
Reviewed by: delphij
Sponsored by: The FreeBSD Foundation

MFC r324441:

Fix freebsd-update(8) erroneous message and exit status when "fetch install" used.

PR: 190660

MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

MFC r307156:

MFportsnap r264740: Use case insensitive match when parsing host(1) output.

Some DNS caches turn "FreeBSD.org" into "freebsd.org", which was causing
the printed SRV records to not match our regex.

PR: 170503

MFC r326082: freebsd-update: do not duplicate patchlist entries

PR: 221079
Submitted by: Masachika ISHIZUKA
Submitted by: ota@j.email.ne.jp
Reviewed by: cperciva

MFC r302534:

Allow - in distribution names. This is needed for freebsd-update to
work with 11.0+, where the debugging symbols use a new naming scheme
for release distribution files.

Errata candidate.

Approved by: re (gjb)