sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

sys/uuid.h: Include sys/types.h

Change the include of sys/cdefs.h to sys/types.h to pick up all the
types. sys/types.h includes cdefs.h.

Sponsored by: Netflix

validate_uuid: absorb the rest of parse_uuid with a flags arg

This makes the naming annoyance (validate_uuid vs. parse_uuid) less of an
issue and centralizes all of the functionality into the new KPI while still
making the extra validation optional. The end-result is all the same as far
as hostuuid validation-only goes.

kern uuid: break format validation out into a separate KPI

This new KPI, validate_uuid, strictly validates the formatting of the input
UUID and, optionally, populates a given struct uuid.

As noted in the header, the key differences are that the new KPI won't
recognize an empty string as a nil UUID and it won't do any kind of semantic
validation on it. Also key is that populating a struct uuid is optional, so
the caller doesn't necessarily need to allocate a bogus one on the stack
just to validate the string.

This KPI has specifically been broken out in support of D24288, which will
preload /etc/hostid in loader so that early boot hostuuid users (e.g.
anything that calls ether_gen_addr) can have a valid hostuuid to work with
once it's been stashed in /etc/hostid.

sys/sys: further 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.

Add a helper function for comparing struct uuids.

Submitted by: Domagoj Stolfa <domagoj.stolfa@gmail.com>
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11138

Decouple the UUID generator from network interfaces by having MAC
addresses added to the UUID generator using uuid_ether_add(). The
UUID generator keeps an arbitrary number of MAC addresses, under
the assumption that they are rarely removed (= uuid_ether_del()).
This achieves the following:
1. It brings up closer to having the network stack as a loadable
module.
2. It allows the UUID generator to filter MAC addresses for best
results (= highest chance of uniqeness).
3. MAC addresses can come from anywhere, irrespactive of whether
it's used for an interface or not.

A side-effect of the change is that when no MAC addresses have been
added, a random multicast MAC address is created once and re-used if
needed. Previusly, when a random MAC address was needed, it was
created for every call. Thus, a change in behaviour is introduced
for when no MAC addresses exist.

Obtained from: Juniper Networks, Inc.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Add parse_uuid() that creates a binary representation of an UUID from
a string representation.

Move the UUID generator into its own function, called kern_uuidgen(),
so that UUIDs can be generated from within the kernel. The uuidgen(2)
syscall now allocates kernel memory, calls the generator, and does a
copyout() for the whole UUID store. This change is in support of GPT.

/* -> /*- for license, minor formatting changes

Introduce {be,le}_uuid_{enc,dec}() functions for explicitly encoding
and decoding UUID's in big endian and little endian binary format.

Wrap function prototype declarations in __BEGIN_DECLS to do the right thing
with them in non-C cases, outside of the kernel.

Include <sys/cdefs.h> for __BEGIN_DECLS/__END_DECLS as other headers seem
to do in this area.

Requested by: Patrick Hartling <patrick@137.org>

Add uuidgen(2) and uuidgen(1).

The uuidgen command, by means of the uuidgen syscall, generates one
or more Universally Unique Identifiers compatible with OSF/DCE 1.1
version 1 UUIDs.

From the Perforce logs (change 11995):

Round of cleanups:
o Give uuidgen() the correct prototype in syscalls.master
o Define struct uuid according to DCE 1.1 in sys/uuid.h
o Use struct uuid instead of uuid_t. The latter is defined
in sys/uuid.h but should not be used in kernel land.
o Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid()
to kern_uuid.c for use in the kernel (currently geom_gpt.c).
o Rename the non-standard struct uuid in kern/kern_uuid.c
to struct uuid_private and give it a slightly better definition
for better byte-order handling. See below.
o In sys/gpt.h, fix the broken uuid definitions to match the now
compliant struct uuid definition. See below.
o In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change.

A note about byte-order:
The standard failed to provide a non-conflicting and
unambiguous definition for the binary representation. My initial
implementation always wrote the timestamp as a 64-bit little-endian
(2s-complement) integral. The clock sequence was always written
as a 16-bit big-endian (2s-complement) integral. After a good
nights sleep and couple of Pan Galactic Gargle Blasters (not
necessarily in that order :-) I reread the spec and came to the
conclusion that the time fields are always written in the native
by order, provided the the low, mid and hi chopping still occurs.
The spec mentions that you "might need to swap bytes if you talk
to a machine that has a different byte-order". The clock sequence
is always written in big-endian order (as is the IEEE 802 address)
because its division is resulting in bytes, making the ordering
unambiguous.