gnuboot/resources/grub/config/grub.cfg

set prefix=(memdisk)/boot/grub

insmod at_keyboard
insmod usb_keyboard
insmod nativedisk
insmod ehci
insmod ohci
insmod uhci
insmod usb
insmod usbms
insmod regexp

terminal_input --append at_keyboard
terminal_input --append usb_keyboard
terminal_output --append cbmemc

gfxpayload=keep
terminal_output --append gfxterm

if [ -f (cbfsdisk)/background.png ]; then
	insmod png
	background_image (cbfsdisk)/background.png
elif [ -f (cbfsdisk)/background.jpg ]; then
	insmod jpeg
	background_image (cbfsdisk)/background.jpg
fi

set default="0"
set timeout=10
set pager=1
set grub_scan_disk="both"

keymap usqwerty
function try_user_config {
	set root="${1}"
	for dir in boot grub grub2 boot/grub boot/grub2; do
		for name in '' osboot_ autoboot_ libreboot_ coreboot_; do
			if [ -f /"${dir}"/"${name}"grub.cfg ]; then
				unset superusers
				configfile /"${dir}"/"${name}"grub.cfg
			fi
		done
	done
}
function search_grub {
	echo -n "Attempting to load grub.cfg from '${1}' devices"
	for i in 0 1 2 3 4 5 6 7 8 9 10 11; do
		for part in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
			try_user_config "(${1}${i},${part})"
		done
		# raw devices e.g. (ahci0) instead of (ahci0,1)
		try_user_config "(${1}${i})"
	done
	echo # Insert newline
}

function try_isolinux_config {
	set root="${1}"
	for dir in '' /boot; do
		if [ -f "${dir}"/isolinux/isolinux.cfg ]; then
			syslinux_configfile -i "${dir}"/isolinux/isolinux.cfg
		elif [ -f "${dir}"/syslinux/syslinux.cfg ]; then
			syslinux_configfile -s "${dir}"/syslinux/syslinux.cfg
		fi
	done
}
function search_isolinux {
	echo "\nAttempting to parse isolinux/syslinux config from '${1}' devices"
	for i in 0 1 2 3 4 5 6 7 8 9 10 11; do
		for part in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
			try_isolinux_config "(${1}${i},${part})"
		done
		# raw devices e.g. (usb0) instead of (usb0,1)
		try_isolinux_config "(${1}${i})"
	done
	echo # Insert newline
}
menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o' {

	if [ "${grub_scan_disk}" != "ata" ]; then
		search_grub ahci
	fi
	if [ "${grub_scan_disk}" != "ahci" ]; then
		search_grub ata
	fi

	# grub device enumeration is very slow, so checks are hardcoded

	# TODO: add more strings, based on what distros set up when
	# the user select auto-partitioning on those installers
	lvmvol="lvm/matrix-bootvol lvm/matrix-rootvol"

	raidvol="md/0 md/1 md/2 md/3 md/4 md/5 md/6 md/7 md/8 md/9"

	# in practise, doing multiple redundant checks is perfectly fast and
	# TODO: optimize grub itself, and use */? here for everything

	for vol in ${lvmvol} ${raidvol} ; do
		try_user_config "${vol}"
	done

	unset ahcidev
	unset atadev
	for i in 11 10 9 8 7 6 5 4 3 2 1 0; do
		for part in 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1; do
			if [ "${grub_scan_disk}" != "ata" ]; then
				ahcidev="(ahci${i},${part}) ${ahcidev}"
			fi
			if [ "${grub_scan_disk}" != "ahci" ]; then
				atadev="(ata${i},${part}) ${atadev}"
			fi
		done
	done

	set pager=0
	echo -n "Attempting to unlock encrypted volumes"
	for dev in ${ahcidev} ${atadev} ${lvmvol} ${raidvol}; do
		if cryptomount "${dev}" ; then break ; fi
	done
	set pager=1
	echo

	# after cryptomount, lvm volumes might be available
	for vol in ${lvmvol}; do
		try_user_config "${vol}"
	done

	search_grub crypto

	if [ "${grub_scan_disk}" != "ata" ]; then
		# Last resort, if all else fails
		set root=ahci0,1
		for p in / /boot/; do
			if [ -f "${p}vmlinuz" ]; then
				linux ${p}vmlinuz root=/dev/sda1 rw
				if [ -f "${p}initrd.img" ]; then
					initrd ${p}initrd.img
				fi
			fi
		done
	fi

	if [ "${grub_scan_disk}" != "ahci" ]; then
		# Last resort (for setups that use IDE instead of SATA)
		set root=ata0,1
		for p in / /boot/; do
			if [ -f "${p}vmlinuz" ]; then
				linux ${p}vmlinuz root=/dev/sda1 rw
				if [ -f "${p}initrd.img" ]; then
					initrd ${p}initrd.img
				fi
			fi
		done
	fi

	true # Prevent pager requiring to accept each line instead of whole screen
}

menuentry 'Search ISOLINUX menu (AHCI)  [a]' --hotkey='a' {
	search_isolinux ahci
}
menuentry 'Search ISOLINUX menu (USB)  [u]' --hotkey='u' {
	search_isolinux usb
}
menuentry 'Search ISOLINUX menu (ATA/IDE)  [d]' --hotkey='d' {
	search_isolinux ata
}
menuentry 'Load test configuration (grubtest.cfg) inside of CBFS  [t]' --hotkey='t' {
	set root='(cbfsdisk)'
	if [ -f /grubtest.cfg ]; then
		configfile /grubtest.cfg
	fi
}
menuentry 'Search for GRUB2 configuration on external media  [s]' --hotkey='s' {
	search_grub usb
}
if [ -f (cbfsdisk)/seabios.elf ]; then
menuentry 'Load SeaBIOS (payload) [b]' --hotkey='b' {
	set root='cbfsdisk'
	chainloader /seabios.elf
}
fi
if [ -f (cbfsdisk)/img/grub2 ]; then
menuentry 'Return to SeaBIOS [b]' --hotkey='b' {
	set root='cbfsdisk'
	chainloader /fallback/payload
}
fi
menuentry 'Poweroff  [p]' --hotkey='p' {
	halt
}
menuentry 'Reboot  [r]' --hotkey='r' {
	reboot
}
if [ -f (cbfsdisk)/img/memtest ]; then
menuentry 'Load MemTest86+  [m]' --hotkey='m' {
	set root='cbfsdisk'
	chainloader /img/memtest
}
fi