lang: core: embedded: provisioner: Add IPXE support

This lets you boot from ipxe. You can run the ipxe shell from their
stock image or the netboot.xyz one. For the latter, press "m", then type
"dhcp" (machine is now pingable!) then type "route" to check the ip.

To boot type:

chain http://192.168.42.1:4280/menu.ipxe

and you're off!

Thanks to frebib for finding the workaround to the VFS bug. The answer
is you need to run the imgfree command to unblock the initrd.

lang/core/embedded/provisioner/files/ipxe-menu.tmpl

@@ -0,0 +1,38 @@
+#!ipxe
+
+menu iPXE Boot Options
+
+item kickstart Install {{ .distro }} {{ .version }} {{ .arch }} ( kickstart )
+item manual Install {{ .distro }} {{ .version }} {{ .arch }} ( manual )
+item shell iPXE shell
+item exit Exit to BIOS
+
+choose --default kickstart --timeout 10000 option && goto ${option}
+
+:kickstartwip
+imgfree
+set server_root {{ .server_base }}
+kernel ${server_root}{{ .distro }}{{ .version }}-{{ .arch }}/vmlinuz ip=dhcp initrd=initrd.magic inst.repo={{ .inst_repo_base }}releases/{{ .version }}/{{ .flavour }}/{{ .arch }}/os/ inst.text inst.ks={{ .ks }} console=ttyS1,115200n8
+initrd ${server_root}{{ .distro }}{{ .version }}-{{ .arch }}/initrd.img
+boot
+
+# The imgfree command works around some bug, which makes our initrd not be seen
+# properly. We would otherwise get a VFS not syncing error on boot.
+
+:kickstart
+imgfree
+kernel {{ .server_base }}{{ .distro }}{{ .version }}-{{ .arch }}/vmlinuz ip=dhcp initrd=initrd.img inst.repo={{ .inst_repo_base }}releases/{{ .version }}/{{ .flavour }}/{{ .arch }}/os/ inst.ks={{ .ks }}
+initrd {{ .server_base }}{{ .distro }}{{ .version }}-{{ .arch }}/initrd.img
+boot
+
+:manual
+imgfree
+kernel {{ .server_base }}{{ .distro }}{{ .version }}-{{ .arch }}/vmlinuz ip=dhcp inst.repo={{ .inst_repo_base }}releases/{{ .version }}/{{ .flavour }}/{{ .arch }}/os/
+initrd {{ .server_base }}{{ .distro }}{{ .version }}-{{ .arch }}/initrd.img
+boot
+
+:shell
+shell
+
+:exit
+exit

lang/core/embedded/provisioner/main.mcl

@@ -80,6 +80,7 @@ class base($config) {
 
 	# eg: equivalent of: https://download.fedoraproject.org/pub/fedora/linux/
 	$inst_repo_base = "http://${router_ip}:${http_port_str}/fedora/" # private lan online, no https!
+	$server_base = "http://${router_ip}:${http_port_str}/" # private lan online, no https!
 
 	$syslinux_root = "/usr/share/syslinux/"
 
@@ -360,11 +361,17 @@ class base:repo($config) {
 
 	$uefi_root = "${uefi_extract_dir}/boot/efi/EFI/fedora/"
 	$uefi_shim = "${uefi_root}shim.efi"
+	$uefi_shimx64 = "${uefi_root}shimx64.efi"
 	tftp:file "/uefi/shim.efi" { # needs leading slash
 		path => $uefi_shim,		# TODO: add autoedges
 
 		Depend => Exec["uefi-extract-${uid}"],
 	}
+	tftp:file "/uefi/shimx64.efi" { # needs leading slash
+		path => $uefi_shimx64,		# TODO: add autoedges
+
+		Depend => Exec["uefi-extract-${uid}"],
+	}
 	tftp:file "/uefi/grubx64.efi" {	# sometimes used?
 		path => "${uefi_root}grubx64.efi",		# TODO: add autoedges
 
@@ -399,6 +406,11 @@ class base:repo($config) {
 
 		#Depend => Pkg[$pkgs],
 	}
+	http:file "/${uid}/vmlinuz" {		# when using ipxe
+		path => $vmlinuz_file,		# TODO: add autoedges
+
+		#Depend => Pkg[$pkgs],
+	}
 
 	$initrd_file = "${distroarch_tftp_prefix}initrd.img"
 	exec "initrd-${uid}" {
@@ -421,6 +433,11 @@ class base:repo($config) {
 
 		#Depend => Pkg[$pkgs],
 	}
+	http:file "/${uid}/initrd.img" {	# when using ipxe
+		path => $initrd_file,		# TODO: add autoedges
+
+		#Depend => Pkg[$pkgs],
+	}
 
 	# this file resource serves the entire rsync directory over http
 	if $mirror == "" { # and $rsync != ""
@@ -626,7 +643,7 @@ class base:host($name, $config) {
 		}
 	}
 
-	$tftp_menu_template = struct{
+	$menu_template = struct{
 		distro => $distro,
 		version => $version,		# 39 for fedora 39
 		arch => $arch,			# could also be aarch64
@@ -634,6 +651,7 @@ class base:host($name, $config) {
 
 		ks => "http://${router_ip}:${http_port_str}/fedora/kickstart/${hkey}.ks", # usually $mac or `default`
 		inst_repo_base => $inst_repo_base,
+		server_base => $server_base,
 	}
 
 	#
@@ -661,20 +679,30 @@ class base:host($name, $config) {
 		"/uefi/grub.cfg-01-${old_mac}"
 	}
 
+	$ipxe_menu = if $mac == "" {
+		"menu.ipxe"
+	} else {
+		"${old_mac}.ipxe"
+	}
+
 	if $bios {
 		tftp:file "${bios_menu}" {	# for bios
-			data => golang.template(deploy.readfile("/files/bios-menu.tmpl"), $tftp_menu_template),
+			data => golang.template(deploy.readfile("/files/bios-menu.tmpl"), $menu_template),
 		}
 	} else {
 		tftp:file "${uefi_menu}" {	# for uefi
 			# XXX: linuxefi & initrdefi VS. kernel & append ?
-			data => golang.template(deploy.readfile("/files/uefi-menu.tmpl"), $tftp_menu_template),
+			data => golang.template(deploy.readfile("/files/uefi-menu.tmpl"), $menu_template),
 
 			#Depend => Pkg[$pkgs_uefi],
 			#Depend => Exec["uefi-extract"],
 		}
 	}
 
+	http:file "/${ipxe_menu}" {	# for ipxe
+		data => golang.template(deploy.readfile("/files/ipxe-menu.tmpl"), $menu_template),
+	}
+
 	# If it's a dir we don't need a suffix, otherwise return the last chunk.
 	$handoff_code_chunk = if strings.has_suffix($prefix, "/") {
 		""