freebsd-dev/sys/boot/efi/boot1/generate-fat.sh
Ed Maste 5e66298138 boot1 generate-fat: generate all templates at once
In advance of other changes to the fat template generation process, have
generate-fat.sh create all template files at the same time so that they
cannot get out of sync.

Also correct a longstanding but where BOOT1_OFFSET was overwritten on
each invocation. A previous version of this patch stored a per-arch
offset (e.g. BOOT1_arm64_OFFSET) but that was deemed unnecessary.
Instead just hardcode the known offset that applies to all archs (0x2d)
and fail if the offset happens to be different.

Ongiong work (using newfs_msdos in bsdinstall and adding msdosfs support
to makefs) will eventually allow us to do away with this fat template
hack altogether, but in the near term we have a few improvements that
will build on this.

Reviewed by:	allanjude, imp, Eric McCorkle
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D10931
2017-09-11 00:37:00 +00:00

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#!/bin/sh
# This script generates the dummy FAT filesystem used for the EFI boot
# blocks. It uses newfs_msdos to generate a template filesystem with the
# relevant interesting files. These are then found by grep, and the offsets
# written to a Makefile snippet.
#
# Because it requires root, and because it is overkill, we do not
# do this as part of the normal build. If makefs(8) grows workable FAT
# support, this should be revisited.
# $FreeBSD$
FAT_SIZE=1600 #Size in 512-byte blocks of the produced image
BOOT1_OFFSET=2d
BOOT1_SIZE=128k
if [ $(id -u) != 0 ]; then
echo "${0##*/}: must run as root" >&2
exit 1
fi
# Record maximum boot1 size in bytes
case $BOOT1_SIZE in
*k)
BOOT1_MAXSIZE=$(expr ${BOOT1_SIZE%k} '*' 1024)
;;
*)
BOOT1_MAXSIZE=$BOOT1_SIZE
;;
esac
echo '# This file autogenerated by generate-fat.sh - DO NOT EDIT' > Makefile.fat
echo "# \$FreeBSD\$" >> Makefile.fat
echo "BOOT1_OFFSET=0x$BOOT1_OFFSET" >> Makefile.fat
echo "BOOT1_MAXSIZE=$BOOT1_MAXSIZE" >> Makefile.fat
while read ARCH FILENAME; do
# Generate 800K FAT image
OUTPUT_FILE=fat-${ARCH}.tmpl
dd if=/dev/zero of=$OUTPUT_FILE bs=512 count=$FAT_SIZE
DEVICE=`mdconfig -a -f $OUTPUT_FILE`
newfs_msdos -F 12 -L EFI $DEVICE
mkdir stub
mount -t msdosfs /dev/$DEVICE stub
# Create and bless a directory for the boot loader
mkdir -p stub/efi/boot
# Make a dummy file for boot1
echo 'Boot1 START' | dd of=stub/efi/boot/$FILENAME cbs=$BOOT1_SIZE count=1 conv=block
# Provide a fallback startup.nsh
echo $FILENAME > stub/efi/boot/startup.nsh
umount stub
mdconfig -d -u $DEVICE
rmdir stub
# Locate the offset of the fake file
OFFSET=$(hd $OUTPUT_FILE | grep 'Boot1 START' | cut -f 1 -d ' ')
# Convert to number of blocks
OFFSET=$(echo 0x$OFFSET | awk '{printf("%x\n",$1/512);}')
# Validate the offset
if [ $OFFSET != $BOOT1_OFFSET ]; then
echo "Incorrect offset $OFFSET != $BOOT1_OFFSET" >&2
exit 1
fi
bzip2 $OUTPUT_FILE
echo 'FAT template boot filesystem created by generate-fat.sh' > $OUTPUT_FILE.bz2.uu
echo 'DO NOT EDIT' >> $OUTPUT_FILE.bz2.uu
echo "\$FreeBSD\$" >> $OUTPUT_FILE.bz2.uu
uuencode $OUTPUT_FILE.bz2 $OUTPUT_FILE.bz2 >> $OUTPUT_FILE.bz2.uu
rm $OUTPUT_FILE.bz2
done <<EOF
amd64 BOOTx64.efi
arm64 BOOTaa64.efi
arm BOOTarm.efi
i386 BOOTia32.efi
EOF