Add UEFI netboot support

If grub's been netbooted, pull the uuid and serial number out of smbios and
hit the API server to get the appropriate configuration.

build_library/grub.cfg

@@ -30,6 +30,25 @@ if [ "$grub_platform" = "efi" ]; then
    fi
 fi
 
+if [ "$net_default_server" != "" ]; then
+   smbios --type 1 --get-uuid 8 --set uuid
+   smbios --type 1 --get-string 7 --set serial
+   set mac=$net_default_mac
+   # Re-DHCP as grub to get the API endpoint
+   net_bootp $net_default_interface
+   # This is awful, but grub doesn't support a nice way to do this
+   for i in "$net_efinet0_dhcp_boot_file" "$net_efinet1_dhcp_boot_file" "$net_efinet2_dhcp_boot_file" "$net_efinet3_dhcp_boot_file" "$net_efinet4_dhcp_boot_file" "$net_efinet5_dhcp_boot_file" "$net_efinet6_dhcp_boot_file" "$net_efinet7_dhcp_boot_file" "$net_efinet8_dhcp_boot_file" "$net_efinet9_dhcp_boot_file"; do
+      if [ "$i" != "" ]; then
+          set endpoint="$i"
+          break
+      fi
+   done
+   if [ "$endpoint" != "" ]; then
+      set url="${endpoint}?uuid=$uuid&serial=$serial&mac=$mac"
+      configfile $url
+   fi
+fi
+
 # Search for the OEM partition, load additional configuration if found.
 if [ "$secure_boot" = "0" ]; then
    search --no-floppy --set oem --part-label OEM --hint "$root"

build_library/grub_install.sh

@@ -43,7 +43,7 @@ case "${FLAGS_target}" in
         CORE_NAME="core.img"
         ;;
     x86_64-efi)
-	CORE_MODULES+=( serial linuxefi efi_gop getenv )
+	CORE_MODULES+=( serial linuxefi efi_gop getenv smbios efinet http )
         CORE_NAME="core.efi"
         ;;
     x86_64-xen)