undionly.kpxe doesn't work if you chainload from a native iPXE, but it's
required for physical machines with NICs that iPXE doesn't natively
support.
In my previous attempt to handle Virtualbox's crippled iPXE, I switched
all BIOS-based boots to use ipxe.pxe. This was a bad idea, so now instead
we specifically recognize third-party iPXE builds, and only chainload
*those* with ipxe.pxe, and stick with undionly.kpxe for the rest.
This guarantees that we load the real OS from an iPXE with a known
featureset, rather than rely on the firmware iPXEs to be correct.
Also switch to ipxe.pxe for BIOS boots instead of undionly.kpxe.
ipxe.pxe works when you chainload from one iPXE to another, whereas
undionly.kpxe encounters some kind of poorly explained bug where
it loses the ability to configure networking.
Tested against the following configurations:
- VirtualBox + BIOS w/ iPXE
- VirtualBox + BIOS w/ Intel UNDI
- VirtualBox + EFI
- KVM + SeaBIOS w/ iPXE
- KVM + OVMF (EFI)
- Dell R610 + Dell BIOS/PXE
Fixes#51, fixes#52.
The cli package is meant for single-shot execution anyway, so
instead of plumbing everything through reentrantly, let's just
have a global you can seed before calling CLI().
The two binaries (Apache2 and GPL) both invoke the cli package to do
the work, the only difference between them is that the GPL binary passes
it embedded ipxe binaries.
In practice, most people will want the standalone binary that Just
Works, the variant that doesn't embed ipxe is going to be for niche
applications only.
This version is still *extremely* barebones, and the unstable tag
in the README applies triple for it, but the code in its current
state is capable of booting x86 and UEFI clients correctly, and
that was hard enough to merit a snapshot checkpoint.
