This allows lua to pass back a command string to be executed as if it were
typed at the loader prompt- loader tries to execute the string first as pure
lua, then parses it and gives lua a chance to intercept before it tries to
execute it itself.
This will be used to implement menu_timeout_command, among other things,
which *should* be used to execute basic loader commands independent of the
chosen interpreter.
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.
printc does not need the features or the overhead of printf. It does not
take formatting strings, and it pipes the single string argument through an
"%s" format.
Instead, use putc directly. This pipes the string through in its entirety as
a series of 'unsigned char's, generally straight to the console emulator.
Discussed with: tsoome
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.
- 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.
Distribution will be done after all of the lualoader manpages are created.
Reviewed by: rpokala
Differential Revision: https://reviews.freebsd.org/D14480
Distribution will be done after all of the lualoader manpages are created.
Reviewed by: rpokala
Differential Revision: https://reviews.freebsd.org/D14479
to fix the memory leak that I introduced in r328426. Instead of
trying to clear up the possible memory leak in all the clients, I
ensure that it gets cleaned up in the source (e.g., ffs_sbget ensures
that memory is always freed if it returns an error).
The original change in r328426 was a bit sparse in its description.
So I am expanding on its description here (thanks cem@ and rgrimes@
for your encouragement for my longer commit messages).
In preparation for adding check hashing to superblocks, r328426 is
a refactoring of the code to get the reading/writing of the superblock
into one place. Unlike the cylinder group reading/writing which
ends up in two places (ffs_getcg/ffs_geom_strategy in the kernel
and cgget/cgput in libufs), I have the core superblock functions
just in the kernel (ffs_sbfetch/ffs_sbput in ffs_subr.c which is
already imported into utilities like fsck_ffs as well as libufs to
implement sbget/sbput). The ffs_sbfetch and ffs_sbput functions
take a function pointer to do the actual I/O for which there are
four variants:
ffs_use_bread / ffs_use_bwrite for the in-kernel filesystem
g_use_g_read_data / g_use_g_write_data for kernel geom clients
ufs_use_sa_read for the standalone code (stand/libsa/ufs.c
but not stand/libsa/ufsread.c which is size constrained)
use_pread / use_pwrite for libufs
Uses of these interfaces are in the UFS filesystem, geoms journal &
label, libsa changes, and libufs. They also permeate out into the
filesystem utilities fsck_ffs, newfs, growfs, clri, dump, quotacheck,
fsirand, fstyp, and quot. Some of these utilities should probably be
converted to directly use libufs (like dumpfs was for example), but
there does not seem to be much win in doing so.
Tested by: Peter Holm (pho@)
One does not simply convert to SUBDIR.yes in stand without making everything
else in the affected files SUBDIR.yes -- there are better ways to do this.
Use SUBDIR.${MK_*} where appropriate. r330248 eliminated most of the
offenders, sweep the rest under the rug.
Differential Revision: https://reviews.freebsd.org/D14545
Makefile.${MACHINE_ARCH} and remove the now-empty files. Generate the
*32 directories on the necessary architectures (well, currently only
amd64) on the fly. Remove LOADER_EFI variable and co-locate it with
EFI.
Differential Review: https://reviews.freebsd.org/D14546
Rather than hardcoding these things. This could lead to some form of loader
localization later, but the main goal at the moment is to get a clear view
of the strings we're outputting and strive to use more string.format() and
less wild concatenation all over the place.
We've included an extra '0' in there (which might get removed later, but
it's maintained for the moment for legacy purposes) which oftentimes
indicate that the following number should be treated as octal. This is not
the case, so note that to prevent future confusion (of myself and others).
Our module bits ended up more stable than I anticipated, so this turns out
to be no longer useful.
If things like this need to come back, we should do it in a separate 'debug'
module to serve as a collection of debugging aides. As a rule, this 'debug'
module would *not* be allowed as a requirement of any other modules in-tree.
- Add screen.default_x and screen.default_y to determine where
screen.defcursor resets the cursor to.
- Use screen.setcursor in screen.defcursor instead of rewriting the escape
sequence.
- Use screen.default_y when resetting the cursor after writing the new
twiddle character, add a comment verbally describing the position just in
case.
It worked on my test setup, but is clearly non-functional on others.
Further examination of check-password.4th showed that it actually reset the
cursor to 0,25 every time and overwrote the previous password prompt. Do
that, and also clear the "Incorrect Password" text if the correct password
gets entered.
twiddle_pos didn't need to be a module-scope local, since it's going to get
reset with every read anyways- it was left-over from other things.
screen.movecursor with a y=-1 setting was from a test of movecursor,
resulting in the twiddle characters being drawn going up the console and
looking quite funky.
This gives some form of feedback while typing, and matches-(ish*) Forth
behavior. The cursor generally rests two column after the password prompt,
then the twiddle is drawn three columns later and the cursor reset to
resting position after being drawn.
I've removed the note about re-evaluating it for security considerations and
instead set it up as a module-local variable that we can set later depending
on environment or something. It's set to false with no chance of changing at
the moment.
*As close as I can tell from reading check-password.4th, because I don't
have an easy test (or deployed) setup for forth loader to check how close
it is. Please do mention if it's not close enough.
There are some _write callbacks left only returning EROFS, replace them
by null_write. return EROFS from null_write().
Reviewed by: cem, imp, kan
Differential Revision: https://reviews.freebsd.org/D14523
Current timeout behavior is to progress in timeout values from MINTMO to
MAXTMO in MINTMO steps before finally timing out. This results in a fairly
long time before operations finally timeout, which may not be ideal for some
use-cases.
Add MAXWAIT that may be configured along with MINTMO/MAXTMO. If we attempt
to start our send/recv cycle over again but MAXWAIT > 0 and MAXWAIT seconds
have already passed, then go ahead and timeout.
This is intended for those that just want to say "timeout after 180 seconds"
rather than calculate and tweak MINTMO/MAXTMO to get their desired timeout.
The default is 0, or "progress from MINTMO to MAXTMO with no exception."
This has been modified since review to allow for it to be defined via CFLAGS
and doing appropriate error checking. Future work may add some Makefile foo
to respect LOADER_NET_MAXWAIT if it's specified in the environment and pass
it in as MAXWAIT accordingly.
Reviewed by: imp, sbruno, tsoome (all previous version)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D14389
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.
screen was also guilty of not-so-great argument names, but it was also
guilty of handling color sequences on its own. Change those bits to using
the color module instead.
As a side note, between color and screen, I'm not 100% sure that returning
the color_value is the right thing to do if we won't generate the escape
sequences. This should be re-evaluated at a later time, and they should
likely return nil instead.
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.
Remove almost all of the _load=XXX options (kept only those relevant
to splash screens, since there were other settings).
Remove the excessively cutesy comment blocks.
Remove excessive comments and replace with similar content
Remove gratuitous blank lines (while leaving some)
We have too many modules to list them all here. There's no purpose in
doing so and it's a giant hassle to maintain. In addition the extra
~500 lines slow this down on small platforms. It slowed it down
so much small platforms forked, which caused other issues...
This is a compromise between those two extremes.
We really only need one loader.conf. The other loader.conf was created
because the current one took forever to parse in FORTH. That will be
fixed in the next commit.
For directories that don't many anything, add NO_OBJ=t just before we
include bsd.init.mk. This prevents them from creating an OBJ
directory. In addition, prevent defs.mk from creating the machine
related links in these cases. They aren't needed and break, at least
on stable, the read-only src tree build.
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.
cli_execute is likely the only exception that we should make, due to it
being a global. We don't really need other globals, so this won't really end
up an epidemic.
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.
These indices were assigned the same values as they would've been implicitly
assigned anyways.
While here, throw terminating commas after the last value of tables.
It should use the common parser, but it should not be processed like a
standard file. Rewite check_nextboot to read the file in, check whether it
should continue, then parse as needed.
This allows us to throw the recently introduced check_and_halt callback
swiftly out the window.
config.parse is now purely a parser, rather than a whole proccessor. The
standard process for loading a config file has been split out into
config.processFile.
This clears the way for having nextboot read its own config file and decide
there whether it should parse the rest of the file.
This is step 1 towards revoking config.parse of it I/O privileges. Ideally,
all reading would be done before config.parse and config.parse would just
take text and parse it rather than being charged with the entire process.
Functionally, the latter error wouldn't necessarily hurt anything. io.write
will just error out as it's not passed a valid file handle. Still, we can do
better than that.
The functionality was correct, but our style guidelines tend to request that
we shy away from using boolean operations in place of explicit comparisons
to nil.
config.parse now takes an extra callback that is invoked on the full text of
the config file. This callback dictates where we should actually try to
parse this file or not.
For nextboot, we use this to halt parsing if we see 'nextboot_enable="NO"'.
If we don't, parse it and write 'nextboot_enable="NO" ' to it. The same
caveat as with forth still applies- writing is only supported by UFS.
Write support (even if it only works on UFS) will be needed for nextboot
functionality.
Reviewed by: cem, imp
Differential Revision: https://reviews.freebsd.org/D14478
We don't support float in the boot loaders, so don't include
interfaces for float or double in systems headers. In addition, take
the unusual step of spiking double and float to prevent any more
accidental seepage.
We need to ensure that we defined Numbers as int64_t everywhere we
build for lua. Previously, we were compiling part of the code with
Numbers as int64_t and part as double. Move lua number definition to a
more-central location
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.
I've also made some not-insignificant changes/additions to this file, to
include the added constants, ACPI changes, boot environment listing, and
some utility functions.
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)
r329725 cleaned up ZFS commands duplicated in multiple places, but userboot
was not setting HAVE_ZFS when MK_ZFS != "no". This resulted in a failure to
boot (as seen in PR 226118) in bhyve, with the following message:
/boot/userboot.so: Undefined symbol "ldi_get_size"
PR: 226118
Glanced at by: imp
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.
Instead of the global namespace, let's attach these to the cli module. Other
users, including the "local" module, can attach functions to the cli module
at will to add other cli commands and things will still Just Work.
This distills down the candidates for functions that may be invoked via the
cli to a minimal set (boot, autoboot, arguments), rather than any function
that happens to live in the global lua namespace.
This will be the translation layer for varargs -> cmd_name, argv for cli
commands. We reserve the right to break exactly what the varargs inclulde,
but this gives us a stable way to pull the arguments out of varargs.
This module will, in the not-so-distant future, grow functionality for
reducing boilerplate in functions that implement cli commands. It will
likely also house most in-tree cli commands.
This seems to have been arbitrary; bootlock_password and password don't seem
to have any documented length restrictions, and loader(8) probably shouldn't
care about whatever GELI passphrase length restrictions might exist.
Reported by: Kalle Carlbark <kalle.carlbark+freebsd@kcbark.net>
As noted in D14267 load_elf.c has a variety of indentation styles. Move
to standard 8 column hard tab indents, 4 space second level indents.
Also includes some whitespace cleanups found by clang-format.
Curiously, changing whitespace seems to cause the md5 of the .o files to differ
these days hence the following testing strategy:
Tested by: objdump -d | md5 (both in-tree clang and lang/gcc6)
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.
Instead of based it off of whether 'kernels' was specified, base it off of a
new variable: kernels_autodetect. If set to yes, we'll run the autodetection
bits and add any detected kernels to the already existing list *after* both
'kernel' and 'kernels'.
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
For the benefit of lualoader, add all bootenvs to environment when
init_zfs_bootenv is invoked. All of the boot environment logic can then be
implemented in pure lua, rather than going back and forth with C to
implement paging.
This stores all boot environments in bootenvs[idx] and the final count of
bootenvs in bootenvs_count.
While here, make a copy of currdev for init_zfs_bootenv since it will be
modifying it and the caller may not necessarily want that. Some of the logic
was shifted around so that the 'currdev' pointer remains at the beginning of
the string and 'beroot' is moved around as needed to modify it or ultimately
store it in zfs_be_root.
The original zfs_bootenv that this was copied from will be able to go away
only if/when forth eventually goes away.
Tested with: lualoader (and local changes to add boot env. support)
Tested with: forth
Reviewed by: cem (earlier version), imp
Differential Revision: https://reviews.freebsd.org/D14435
The Makefile gives the impression that ext2fs and msdos were excluded
(they weren't) and that you could exclude cd9660 and ufs support (you
couldn't). Allow those to be excluded.
We need to look, in the future, at trimming the number of supported
filesystems, and this will make that easier.
There's no reason to have multiple copies of lszfs and
reloadbe. Consolidate them into one location. Also ldi_get_size is the
same everywhere (except sparc64). Make it the same everywhere as the
common definition is more general and will work on spar64.
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.
Provide a way for out-of-tree users of lualoader to patch into the loader
system without having to modify our distributed scripts.
Do note that we can't really offer any API compatibility guarantees at this
time due to the evolving nature of lualoader right now.
This still has some utility as local modules may add commands at the loader
prompt without relying heavily on lualoader features- this specific
functionality is less likely to change without more careful consideration.
Reviewed by: cem (earlier version)
Differential Revision: https://reviews.freebsd.org/D14439
I can't find any good reason these aren't enabled, so enable them.
The silent runs will only return false on actual parse errors, so it's ok to
be loud about those failures.
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.
Track the latest value we've set an environment variable to, and only
restore those that are unchanged from that.
This gives us some leeway to make sure we're not clobbering variables
overwritten by menu changes.
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.
core.boot and core.autoboot may both take arguments; add a helper to cleanly
append an argstring to the given loader command.
Also provide a popFrontTable() that we'll use pop the command name off of an
argv table. We don't have the table library included, and including it is
non-trivial, so we'll implement this one function that we need in lua for
the time being.
If the user's selected a kernel, we really should be trying to load that one
instead of falling back to some default kernel.
This should generally be a no-op and most desirable, unless you really
enjoyed surprises.
Provisioned from MACHINE/MACHINE_ARCH on the system, expose loader.machine
and loader.machine_arch respectively.
These may be used to hide ACPI option on non-applicable archs.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D14446
In the remaining error case, return a 3-tuple consistent with the other
error return case.
Document how to invoke lfs.attributes() and detect/decode error return in
example comments.
Reviewed by: kevans
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14451
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.
If we failed to execute the input line as pure lua, run the command through
parse for consistent argument parsing. Pass the parsed arguments through to
a global "cli_execute" written in Lua, which is expected to either handle it
or pass it back through to interp_builtin_cmd (via loader.command).
lua-handled cli commands will then exist as globals in whatever module they
most belong in, and invocations at the loader prompt will magically dispatch
to them if they exist.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D14450
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 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.
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.
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().
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.
lualoader does a pretty good job of reverting any environment changes now.
It will even wipe out boot_verbose if it's set explicitly in loader.conf(5)
and overwritten in the boot options menu.
Future work will likely change this, as explicit choices made in the menu
should probably override the new loader.conf(5). I don't suspect this will
cause much grief, though, so it is not a high priority until boot
environment support actually lands.
This will be used when boot environment support lands to make a good-faith
effort to apply any new loader.conf(5) environment settings atop the default
configuration that we started with.
