Autoload drivers dropped into `\\sprout\\drivers`

[Conan-Kudo]

Description

Sprout already supports auto-discovering and configuring itself for operating system menu entries (with BLS enabled systems), I think it would also make sense for it to auto-discover drivers installed into /boot/efi/EFI/sprout/drivers like how systemd-boot and other boot managers do so that a simple static configuration file can be used. Obviously it would skip EFI binaries that don't match its own architecture.

This would also make it simple to deal with multi-arch EFI setups like x64 + ia32 on a single x86_64 image (which is how Fedora ships for x86_64).

Code of Conduct

• I agree to follow the Sprout Code of Conduct.

[Conan-Kudo]

To clarify, I'm looking for behavior similar to systemd-boot (documented here):

During initialization, sd-boot automatically loads all driver files placed in the /EFI/systemd/drivers/ directory of the ESP. The files placed there must have an extension of the EFI architecture ID followed by .efi (e.g. for x86-64 this means a suffix of x64.efi). This may be used to automatically load file system drivers and similar, to extend the native firmware support.

[Conan-Kudo]

And if possible, these drivers should be able to be verified with the distribution signing key rather than requiring the Microsoft one.

[azenla]

We should be able to make this work, I will look into this in the coming weeks. I believe that the drivers already support being signed by the distribution key as we ask the shim to verify it, you can take a look at:

sprout/crates/boot/src/drivers.rs

Lines 28 to 30 in fafabe2

	// Load the driver image using the image loader support module.
	// It will determine if the image needs to be loaded via the shim or can be loaded directly.
	let image = ImageLoader::load(request)?;