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.
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.
Loading the kernel and modules can be really slow. Loading before the menu
draws and every time one changes kernel/boot environment is even more
painful.
Defer loading until we either boot, auto-boot, or escape to loader prompt.
We still need to deal with configuration changes as the boot environment
changes, but this is generally much quicker.
This commit strips all ELF loading out of config.load/config.reload so that
these are purely for configuration. config.loadelf has been created to deal
with kernel/module loads. Unloading logic has been ripped out, as we won't
need to deal with it in the menu anymore.
Discussed in part with: allanjude
r329550 introduced config.kernel_loaded. config.load() doesn't provide a
means of overriding the kernel to load, but that likely isn't necessary as
it will not be a common case. When loading the kernel, just attempt to load
the kernel previously loaded and specified in config.kernel_loaded.
If we haven't loaded a kernel yet, config.kernel_loaded will be unset/nil
and the "default"/first kernel found will be loaded. If we've loaded a
kernel, we'll try to load that same kernel again and fallback to the default
kernel if we need to.
This in also in support of upcoming boot environment support.
'nil' means the 'first kernel found in module_path', which is the same
interpretation as passing 'nil' to loadkernel.
Otherwise, it denotes the name of a kernel that we've successfully loaded.
When reloaded later, we will still need to do the full search again to
locate the actual kernel in case things have changed, so just the name is
good enough.
This is in support of upcoming boot environment support. vfs.root.mountfrom
and currdev will be changed, then we will reload configuration and attempt
to reload the currently chosen kernel unless we shouldn't.
Some other points I think we need to be consistent on:
- Spacing around string concatenation (always)
- Test against 'nil' explicitly rather than relying on 'not' for things that
reasonably won't be returning a boolean. e.g. loader.getenv
Eventually this will all get formalized somewhere.
Once we've successfully loaded a kernel, we add its directory to
module_path. If we switch kernels with the kernel selector, we again prepend
the kernel directory to the current module_path and end up with multiple
kernel paths, potentially with mismatched kernel/modules, added to
module_path.
Fix it by caching module_path at load() time and using the cached version
whenever we load a new kernel.
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.
This is the procedure that config.loadkernel tries to go through, but
reloading kernel config didn't use this function. Amend config.loadkernel to
take an optional other_kernel.
While here, be a little more verbose ("Trying to load kernel") so that it's
easy to follow where we've gone wrong.
1.) Instead of string.function(s, ...), use s:function(...)
2.) Don't try to concatenate `res`, it was just tested to be nil
3.) Note that "Loading configuration" is configured modules, and be a little
more precise in mentioning what failed ("loading of one or more modules")
An empty module_path to start with isn't ideal, but if all modules are
contained within a kernel directory (which is what we just tested) then it
isn't strictly an error. Don't assume that module_path has a value already.
When we fail to load the kernel, printing the result (which is guaranteed to
be nil) is not intended; print the name of the kernel.
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
