1#!/bin/sh
2
3# This script generates the dummy FAT filesystem used for the EFI boot
4# blocks. It uses newfs_msdos to generate a template filesystem with the
5# relevant interesting files. These are then found by grep, and the offsets
6# written to a Makefile snippet.
7#
8# Because it requires root, and because it is overkill, we do not
9# do this as part of the normal build. If makefs(8) grows workable FAT
10# support, this should be revisited.
11
12# $FreeBSD: stable/11/stand/efi/boot1/generate-fat.sh 332746 2018-04-19 01:10:53Z kevans $
13
14FAT_SIZE=1600 			#Size in 512-byte blocks of the produced image
15
16BOOT1_OFFSET=2d
17BOOT1_SIZE=384k
18
19if [ $(id -u) != 0 ]; then
20	echo "${0##*/}: must run as root" >&2
21	exit 1
22fi
23
24# Record maximum boot1 size in bytes
25case $BOOT1_SIZE in
26*k)
27	BOOT1_MAXSIZE=$(expr ${BOOT1_SIZE%k} '*' 1024)
28	;;
29*)
30	BOOT1_MAXSIZE=$BOOT1_SIZE
31	;;
32esac
33
34echo '# This file autogenerated by generate-fat.sh - DO NOT EDIT' > Makefile.fat
35echo "# \$FreeBSD\$" >> Makefile.fat
36echo "BOOT1_OFFSET=0x$BOOT1_OFFSET" >> Makefile.fat
37echo "BOOT1_MAXSIZE=$BOOT1_MAXSIZE" >> Makefile.fat
38
39while read ARCH FILENAME; do
40	# Generate 800K FAT image
41	OUTPUT_FILE=fat-${ARCH}.tmpl
42
43	dd if=/dev/zero of=$OUTPUT_FILE bs=512 count=$FAT_SIZE
44	DEVICE=`mdconfig -a -f $OUTPUT_FILE`
45	newfs_msdos -F 12 -L EFISYS $DEVICE
46	mkdir stub
47	mount -t msdosfs /dev/$DEVICE stub
48
49	# Create and bless a directory for the boot loader
50	mkdir -p stub/efi/boot
51
52	# Make a dummy file for boot1
53	echo 'Boot1 START' | dd of=stub/efi/boot/$FILENAME cbs=$BOOT1_SIZE count=1 conv=block
54	# Provide a fallback startup.nsh
55	echo $FILENAME > stub/efi/boot/startup.nsh
56
57	umount stub
58	mdconfig -d -u $DEVICE
59	rmdir stub
60
61	# Locate the offset of the fake file
62	OFFSET=$(hd $OUTPUT_FILE | grep 'Boot1 START' | cut -f 1 -d ' ')
63
64	# Convert to number of blocks
65	OFFSET=$(echo 0x$OFFSET | awk '{printf("%x\n",$1/512);}')
66
67	# Validate the offset
68	if [ $OFFSET != $BOOT1_OFFSET ]; then
69		echo "Incorrect offset $OFFSET != $BOOT1_OFFSET" >&2
70		exit 1
71	fi
72
73	xz -f $OUTPUT_FILE
74done <<EOF
75	amd64	BOOTx64.efi
76	arm64	BOOTaa64.efi
77	arm	BOOTarm.efi
78	i386	BOOTia32.efi
79EOF
80