loader: Move drawer.lua over to gfx table.

Drawer.lua is the only bit of lua code in the base that uses any of the
functons moved from the loader table to the gfx table. Move the main
code to using the gfx dispatch. Add compat code for running on old
loaders that creates the newer-style gfx table with the term_* functions
we call in it populated. This will even work on the super old versions
of the loader that don't have them (we'll still skip using them).

Sponsored by: Netflix
Reviewed by: kevans
Differential Revision: https://reviews.freebsd.org/D43908

Remove $FreeBSD$: two-line lua tag

Remove /^--\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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

lualoader: allow brands to specify a shift

Some brands will want to specify a shift to make sure they're properly
centered; let it happen.

lualoader: remove shadowed local from graphics:drawitem()

for loop vars are local already and distinct from this earlier
declaration; remove it.

loader: do not output empty menu title

As we output spaces around the menu title, we should also check,
if the title is actually empty string.

PR: 255299
Submitted by: Jose Luis Duran
Reported by: Jose Luis Duran
MFC after: 1 week

loader: insert spaces around menu title

Small visual nit, make menu title more clean

MFC after: 3 days

loader: remove BORDER_PIXELS

BORDER_PIXELS is left over from picking up the source from illumos
port. Since FreeBSD VT does not use border in terminal size
calculation, there is no reason why should loader use it.

MFC after: 1 week

lualoader: use floor division to get correct type

This fixes the positioning of the "Welcome to FreeBSD" heading, which was
misplaced after the recent update to Lua 5.4. The issue was previously
masked by a compatibility knob in Lua 5.3 that would cause float-tagged
numbers to render faithfully without the decimal component. Lua 5.4 dropped
that and ensures that it always prints a decimal component, even if it has
to append a ".0" to the value.

Standard division produces a "float", floor division (//) can be used to
guarantee an integer. Floating point operations have been completely ripped
out of the liblua compiled for the bootloader, so this is a nop. This is
decidedly better than trying to hack out the float tag entirely.

Reported-by: mjg, probably others
MFC-after: 3 days

loader: implement framebuffer console

Draw console on efi.
Add vbe framebuffer for BIOS loader (vbe off, vbe on, vbe list,
vbe set xxx).
autoload font (/boot/fonts) based on resolution and font size.
Add command loadfont (set font by file) and
variable screen.font (set font by size). Pass loaded font to kernel.

Export variables:
screen.height
screen.width
screen.depth

Add gfx primitives to draw the screen and put png image on the screen.
Rework menu draw to iterate list of consoles to enamble device specific
output.

Probably something else I forgot...

Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D27420

lualoader: improve the design of the brand-/logo- mechanism

In the previous world order, any brand/logo was forced to pull in the
drawer and call drawer.add{Brand,Logo} with the name their brand/logo is
taking and a table describing it.

In the new world order, these files just need to return a table that maps
out graphics types to a table of the exact same format as what was
previously being passed back into the drawer. The appeal here is not needing
to grab a reference back to the drawer module and having a cleaner
data-driven looking format for these. The format has been renamed to 'gfx-*'
prefixes and each one can provide a logo and a brand.

drawer.addBrand/drawer.addLogo will remain in place until FreeBSD 13, as
there's no overhead to them and it's not yet worth the break in
compatibility with any pre-existing brands and logos.

Reviewed by: freqlabs
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D24966

lualoader: improve drawer error handling

At least one user has landed in a scenario where logo files appear to be
misnamed, and we failed to find them. Our fallback for missing logodefs is
orb/orbbw, based on the color status. In a scenario where we can't locate
the logos, though, this is not ideal. Add in one more layer of fallback
to properly just don't draw any logo if the fan has been jam packed with
foreign material.

PR: 246046
MFC after: 3 days

lualoader: Revert to ASCII menu frame for serial console

The box drawing characters we use aren't necessarily safe with a serial
console; for instance, in the report by npn@, these were causing his xterm
to send back a sequence that lua picked up as input and halted the boot.
This is less than ideal.

Fallback to ASCII frames for console with 'comconsole' in it. This is a
partial revert r338108 by imp@ -- instead of removing the menu entirely and
disabling color/cursor sequences, just reverting the default frame to ASCII
is enough to not break in this setup.

Reported by: npn
Triaged and recommended by: tsoome

loader: use teken teminal emulator for x86 and uefi

Replace mini cons25 emulator with teken, this does enable us proper console
terminal for loader and will make it possible to implement different
back end callbacks to draw to screen.

At this time we still only "draw" in text mode.

lualoader: Add drawer-exported variables for default logodefs

Uncovered while writing the documentation from this, we previously
explicitly fell back to orb or orbbw if an invalid or incompatible logodef
was selected -- in contrast to branddefs, which have an exported variable
that one can whip up a quick local.lua to override in a safe manner that
works regardless of whether or not loader.conf(5) successfully loads.

lualoader: Hide the rest of the private interfaces

These are less controversial than the others, thus done in a separate
commit. These are all used internally and ways to override are provided via
soon-to-be-documented API or loader.conf(5) variables.

lualoader: Hide most of the internal drawing functions

Ideally, all of the functionality to revamp the loader screen has associated
APIs that are flexible enough that third-party scripts wouldn't need to
override these.

lualoader: Stop exporting drawer.draw

drawer.draw is the back-end for drawlogo and drawbrand and should not be
used directly.

lualoader: Allow brand-*.lua for adding new brands

dteske@, I believe, had originally pointed out that lualoader failed to
allow logo-*.lua for new logos to be added. When correcting this mistake, I
failed to do the same for brands.

Correct the sub-mistake: creating new brands is almost identical to creating
new logos, except one must use `drawer.addBrand` and 'graphic' is the only
valid key for a branddef at the moment.

While here, I've added `drawer.default_brand` to be set to name of brand to
be used (e.g. 'fbsd', project default).

Eventually this whole goolash will be documented.

Reported by: kmoore, iXsystems

lualoader: Don't try to lookup a nil logo

lualoader: Split logodefs out into logo-* files

This commit splits all of the logodefs/graphics out into their own own files
and provides a method for these files to register their logodefs with the
drawer. Graphics are now loaded on demand if they don't exist in the current
set of logodefs.

The drawer module becomes a little easier to navigate through without all of
the graphics mixed in. It's also easy to do one-off graphics like the
9.2 Die Hard tribute by dteske@ without adding even more to our memory
requirements.

lualoader: Use printc when we expect ANSI escape sequences

lualoader: logdef -> logodef typo

lualoader: Shift menu+brand even for logo=none with customized pos

lualoader: Tweak positioning and fix an off-by-one

- All of our default positions were offset from forth
- Our menu frame size was smaller than in forth
- Logo/brand drawing had an off-by-one, drawing one column lower on the
screen than they should have been.
- While here, switch a print() to printc() as it's expected that logos may
contain color and other escpae sequences that we'll need to honor.

lualoader: Respect loader_menu_title_align

It may be set to "left" or "right" -- any other value will cause the title
to be centered.

I've chosen to position these things just inside the vertical borders,
rather than overlapping the corners. This is an arbitrary choice and easily
amendable if this looks terrible.

lualoader: Respect loader_menu_title, prepare for align

lualoader: Use global printc instead of loader.printc

r330282 registered loader.printc as printc, so use it instead. This makes
sense for a couple reasons, the major point being that it reads a little bit
easier and pairs nicely with the global 'print'.

Similar cases can not really be made for other loader.* functions as most of
them are either highly specific to our use-case or usually available in
other modules, such as `os`. printc does not have a standard implementation
in the Lua world(*), so we have a little more leeway with it, and it's kind
of a special case of the globally available 'print'.

(*) I've been in the Lua world for all of two weeks, so this could be wrong.

lualoader: Steamroll the box-drawing

- Add drawer.frame_styles to map out the kinds of characters we need for the
different loader_menu_frame values
- Respect loader_menu_frame, default to double[*]
- (imp) Use loader.printc instead of print- print adds a newline to the
output, which is not the right thing we want to be doing.
- (imp) Draw horizontal frames a little more efficiently- setting the cursor
after every line segment is horribly inefficient, especially on serial
consoles. Halve the number of characters written at the expense of an
additional loop to draw the bottom frame, which is likely more efficient
in the long run for some of less ideal scenarios.

[*] menu.4th(8) claims that the default here was single, but unset
loader_menu_frame yielded double and we didn't have any overrides in the
default loader.conf(5), so double it is.

lualoader: Use string literal \xNN instead of string.char()

lualoader: More argument name expansion, part 2

screen also has some instances, but it also has other cleanup to go with it.
Because of this, I will be committing the screen changes separately.

lualoader: Clean up naming conventions a little bit

We mostly use camel case for function names, but some local functions got
mixed in using internal underscores. Doubles down on camel case.

lualoader: Remove unused variable; we now use the effective line number

lualoader: Track effective line number, use it for drawing

Takes into account hidden entries, so that we don't draw blank lines in
place of a hidden item.

lualoader: Use "local function x()" instead of "local x = function()"

The latter is good, but the former is more elegant and clear about what 'x'
is. Adopt it, preferably only using the latter kind of notation where needed
as values for tables.

Add SPDX tags to lua files

lualoader: Attend to some 80-col issues, pointed out by luacheck

Graphics have a tendency to cause 80-col issues, so make an exception to our
standard indentation guidelines for these graphics. This does not hamper
readability too badly.

Two 40-column strings of spaces is trivially replaced with
string.rep(" ", 80)

lualoader: Address some 'luacheck' concerns

luacheck pointed out an assortment of issues, ranging from non-standard
globals being created as well as unused parameters, variables, and redundant
assignments.

Using '_' as a placeholder for values unused (whether it be parameters
unused or return values unused, assuming multiple return values) feels clean
and gets the point across, so I've adopted it. It also helps flag candidates
for cleanup later in some of the lambdas I've created, giving me an easy way
to re-evaluate later if we're still not using some of these features.

lualoader: Replace 8-space indentation with a single tab

lualoader: Allow carousel 'items' to be a table as well as a function

We don't have any in-tree users of this, but for a static set of carousel
options having to define a callback is excessive.

lualoader: Simplify menu definitions a little further

Allow "name" entries to be simple strings, instead of just functions. We
know whether we support colors or not by the time any of this is setup, so
all menu names that are basically static with colors sprinkled in are good
candidates for simplification.

Also simplify "func" in many cases where it's just invoking another function
with no arguments. The downside to this simplification is that the functions
called can no longer be trivially replaced by a local module. The upside is
that it removes another layer of indirection that we likely don't need.

These can be re-evaluated later if a compelling argument is raised, on a
case-by-case basis, for replacement.

lualoader: Drop name requirement for menu separators

lualoader: Drop excessive parenthesizing

This was also a convenience convention (for me) that is not very lua-tic.
Drop it.

I've maintained some parentheses where I'd prefer them, for example,
'if x or y or (z and w) then', but these situations are far and few between.

lualoader: Drop terminating semicolons

This was previously chosen out of convenience, as we had a mixed style and
needed to be consistent. I started learning Lua on Friday, so I switched
everything over. It is not a very lua-nic convention, though, so drop it.

Excessive parenthesizing around conditionals is next on the chopping block.

lualoader: Move carousel storage out into config

Carousel storage doesn't need to happen in the menu module, and indeed
storing it there introduces a circular reference between drawer and menu
that only works because of global pollution in loader.lua.

Carousel choices generally map to config entries anyways, making it as good
of place as any to store these. Move {get,set}CarouselIndex functionality
out into config so that drawer and menu may both use it. If we had more
carousel functionality, it might make sense to create a carousel module, but
this is not the case.

stand/lua: Consistently organize modules

We follow pretty closely the following structure of a module:

1. Copyright notice
2. Module requires
3. Module local declarations
4. Module local definitions
5. Module exports
6. return

Re-organize the one-offs (config/drawer) and denote the start of module
exports with a comment.

stand/lua: Consistently declare local functions at module scope

Declare these adjacent to the local definitions at the top of the module,
and make sure they're actually declared local to pollute global namespace a
little bit less.

stand/lua: Insert helpful comment for drawer.branddefs

stand/lua: Stick a copyright notice on drawer.lua

stand/lua: Use 'graphic' instead of 'logo' for table depicting graphics

This is a more sensible name that offers less redundancy when referring to
it (vs. logodef.logo). Switch to it while the getting is good.

stand/lua: Refactor brands into drawer.branddefs

stand/lua: Refactor logos into drawer.logodefs table

This refactor makes it straightforward to add new logos for drawing and
organizes logo definitions in a logical manner.

The graphic to be drawn for each logo may again be modified outside of
drawer, but it must be done on a case-by-case basis as a modification to the
loader_logo.

stand/lua: Reduce exposure of the drawer module

As part of an effort to slowly reduce our exports overall to a set of stable
properties/functions, go ahead and reduce what drawer exposes to others.

The graphics should generally not be modified on their own, but their
position could be modified if additional grahics also need to be drawn.
Export position/shift information, but leave the actual graphic local to
the module.

The next step will be to create a 'menudef' that gets exported instead, with
each entry in the menudef table describing the graphic to be drawn along
with specific positioning information.

stand/lua: Move drawer.menu_name_handlers further up

As a good candidate for modification, move this table further up in the
module to improve visibility.

stand/lua: Add and use drawer.menu_name_handlers

Pull out specialized naming behavior into drawer.menu_name_handlers. This is
currently only needed for the carousel entry, where naming is based on the
current choice and the menu item purposefully does not store this state.

The setup was designed so that every type can have a special name handler,
and the default action is to simply use the result of entry.name().

stand/lua: Re-order locals after copyright notice; require comes first

stand/lua: Round up some more style.lua(9) concerns

stand/lua: Call menu_entries if it's a function

If we've fetched menu.entries and it turns out it's a function, call it to
get the actual menu entries.

This will be used to swap multi-/single- user boot options if we're booting
single user by default (boot_single="YES" in loader.conf(5)). It can also be
used fairly easily for other non-standard situations.

stand/lua: Store menu entries in an "entries" table

Instead of directly listing them in menu.welcome and menu.boot_options,
store them at menu.welcome.entries and welcome.boot_options.entries.

This will come into play later when we need to re-order the welcome menu if
boot_single is specified.

stand/lua: Addres style.lua(9) concern

stand/lua: Allow menu items to be conditionally (in)visible

This will be used to conditionally show/hide the boot environment menu.

stand/lua: Style pass

These are the style points that I'd like to try and maintain in our lua
scripts:
- Parentheses around conditionals
- Trailing semicolons, except on block terminators
- s:method(...) instead of string.method(s, ...) where applicable

There's likely more, but that'll get hammered out as we continue.

stand/lua: Create/use some MENU_ constants where applicable

stand/lua: Create a "carousel" menu entry type

This is a pre-cursor to boot environment support in lualoader. Create a new
menu item type, "carousel_entry", that generally provides a callback to get
the list of items, a carousel_id for storing the current value, and the
standard name/func functions that an entry has.

The difference between this and a normal menu item, functionally, is that
selecting a carousel item will automatically rotate through available items
and wrap back at the beginning when the list is exhausted.

The 'name' function takes the choice index, current choice, and the list of
choices as parameters so that the menu item can decorate the name freely as
desired.

The 'func' function takes the current choice as a parameter, so it can act
accordingly.

The kernel menu item has been rewritten to use the carousel_entry type as
both an example and initial test of its functionality before it is used for
boot environment options.

stand/lua: Allow menu items to not have explicit aliases

This will generally be used for cases like "Back to main menu" that already
have global aliases installed.

Add the lua scripts from the lua-bootloader SoC

These are the .lua files from from Pedro Souza's 2014 Summer of Code
project. Rui Paulo, Pedro Arthur and Wojciech A. Koszek also
contributed.

Obtained from: https://wiki.freebsd.org/SummerOfCode2014/LuaLoader
Sponsored by: Google Summer of Code

Improve the SoC lua menu code to bring it in line with forth
menu functionality

Submitted by: Zakary Nafziger
Sponsored by: FreeBSD Foundation

Use loader.setenv and loader.unsetenv instead of loader.perform

Convert from include("/boot/foo.lua") to foo = require("foo");
to bring in line with latest lua module conventions.

Enforce a uniform style for the new .lua files:
o hard tab indenation for 8 spaces
o don't have if foo then bar; else bas; end on one line

MFC After: 1 month
Relnotes: yes
Differential Review: https://reviews.freebsd.org/D14295