loader.interpret should not be used for executing loader commands from an
untrusted source (e.g. environment vars) as it will allow execution of
arbitrary Lua. Replace it with a call to the recently introduced
cli_execute_unparsed, which parses it out as a loader command and then
dispatches it as a loader command. This effectively filters out arbitrary
Lua.
- 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.
Rather than before the menu is drawn. The drawer is going to reset the
crusor position as soon as it draws anything anyways, so doing it before
serves no purpose. Setting it after is needed so we don't clobber the menu
when we start booting.
This is motivated by a want to reduce heap usage if the menu is being
skipped. Currently, the menu module must be loaded regardless of whether
it's being skipped or not, which adds a cool ~50-100KB worth of memory
usage.
Move the menu skip logic out to core (and remove a debug print), then check
in loader.lua if we should be skipping the menu and avoid loading the menu
module entirely if so. This keeps our memory usage below ~115KB for a boot
with the menu stripped.
Also worth noting: with this change, we no longer explicitly invoke autoboot
if we're skipping the menu. Instead, we let the standard loader behavior
apply: try to autoboot if we need to, then drop to a loader prompt if not or
if the autoboot sequence is interrupted. The only thing we still handle
before dropping to the loader autoboot sequence is loadelf(), so that we can
still apply any of our kernel loading behavior.
Instead of a single-letter parameter ('m'), use something a little more
descriptive and meaningful: 'menudef' ("menu definition") -- these functions
expect to be passed a menudef, so call it what it is.
While here, throw an assertion in that we have a handler for the selected
menu item. This is more of a debugging aide so that it's more obvious when
one is testing a menudef that they've added an entry item that we don't
handle.
This is an improvement over the past behavior of ignoring the unknown menu
entry.
This cleans up the odd approach to menu drawing. Instead of tracking
validity, we track the menu that was drawn on the screen. Whenever we draw a
menu, we'll set this to that menu.
Anything that invalidates the screen should go ahead and trigger an explicit
redraw, rather than finding a wy to set screen_invalid.
The currently drawn menu is then reset in menu.run as we exit the menu
system, so that dropping to the loader prompt or leaving menu.run() will
just behave as expected without doing redundant work every time we leave a
menu.
In the common case, this will effectively do nothing as the menu will get
redrawn as we leave submenus regardless of whether the screen has been
marked invalid or not
However, upon escape to the loader prompt, one could do either of the
following to re-enter the menu system:
-- Method 1
require('menu').run()
-- Method 2
require('menu').process(menu.default)
With method 1, the menu will get redrawn anyways as we do this before
autoboot checking upon entry. With method 2, however, the menu will not be
redrawn without this invalidation.
Both methods are acceptable for re-entering the menu system, although the
latter method in the local module for processing new and interesting menus
is more expected.
There's no reason for autoboot handling to be mixed in with menu processing.
It is a distinct process that should only be done once when entering the
menu system.
menu.process has been modified to take an initial keypress to process and to
only draw the screen initially if it's been invalidated. The keypress is
kind of a kludge, although it could be argued to be a potentially useful
kludge if there are other processes that may need to feed a keypress into
the menu system.
In general, every menu redraw is going to require a screen clear and cursor
reset. Each redraw also has the potential to invalidate the alias table, so
we move the alias table being used out into a module variable. This allows
third party consumers to also inspect or update the alias table if they need
to.
While here, stop searching the alias table once we've found a match.
This is driven by an urge to separate out the bits that really only need to
happen when the menu system starts up. Key points:
- menu.process now does the bulk of menu handling. It retains autoboot
handling for dubious reasons, and it no longer accepts a 'nil' menu to
process as 'the default'. Its return value is insignificant.
- The MENU_SUBMENU handler now returns nothing. If menu.process has exited,
then we continue processing menu items on the parent menu as expected.
- menu.run is now the entry point of the menu system. It checks whether the
menu should be skipped, processes the default menu, then returns.
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.
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)
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.
Attempt to autoboot when we open the default menu, and only when we open the
default menu. This alleviates the need for checking menu.already_autoboot,
because we're not trying to autoboot every time we open a submenu.
I note that escaping to loader prompt and going back to the menu (by running
require('menu').run() at the loader prompt) will happily work and not
re-initiate the autoboot sequence since "Escape to loader prompt" disables
the autoboot_delay.
This looks a little bit differently than the forth version for the time
being, just to get off the ground- rather than a paging system, it's
implemented as a simple carousel like the kernel selector.
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D14436
This matches forth behavior. Hitting "6" when autobooting at the welcome
menu will now take you directly to the "Boot Options" menu.
We likely have some slight optimizations we should make, like not checking
autoboot every time we open a new menu and things of this nature. Further
work will go towards this end.
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.
The intent here is to abstract away the name of the default menu. The
default menu is still the welcome menu, but this detail doesn't need to
matter to things outside of the menu module. You may change the default
menu, but one would need to modify a specific menu.
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.
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.
This should be functional and roughly equivalent to the Forth version.
Stop doing a loadelf() on menu exit now that we can DTRT with boot
invocations. autoboot interception will follow not long after.
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.
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.
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.
This is a bit cleaner than our former method of an if ... else chain of
handlers. Store handlers in the menu.handlers table so that they may be
added to or removed dynamically.
All handlers take the current menu and selected entry as parameters, and
their return value indicates whether the menu processor should continue or
not. An omitted return value or 'true' will indicate that we should
continue, while returning 'false' will indicate that we should exit the
current menu.
The omitted return value behavior is due to continuing the loop being the
more common situation.
Building the swapped welcome menu (first two items swapped) is kind of a
sluggish, because it requires a full (recrusive) shallow copy of the welcome
menu. Cache the result of that and re-use it later, instead of building it
everytime.
While here, don't create temporary locals just for swapping. The following
is just as good:
x, y = y, x;
Reported by: Alexander Nasonov <alnsn@yandex.ru> (swapping)
[Enter] should be moved to the single user menu item when we swap them.
Define a non-standard menu entry function "alternate_name" to use for this
purpose for ultimate flexibility if we change our minds later. When we're
booting single user, make a shallow copy of the menu that we'd normally
display and swap the items and their name functions to use alternate_name
instead. Toggling single user in the options menu and going back to the main
menu will now correctly reflect the current boot setting with the first two
menu options and "[Enter]" will always be on the right one.
This shallow copy technique has the chance of being quite slow since it's
done on every redraw, but in my testing it does not seem to make any obvious
difference.
shallowCopyTable could likely belong better in a general-purpose utility
module, but this (and the key constnats) are the only candidates we have at
the moment so we'll drop it into our core stuff for the moment and consider
re-organization at a later date.
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.
Menus are actually defined as entries in the 'menu' table. These local
declarations have not been used in the history of our in-tree lua scripts,
so give them the boot.
