#!/bin/rc
# mkusbboot - make a bootable standalone plan 9 image to copy to a usb disk.
#
# due to name clashes in /srv, will only work on a machine
# without a fossil named `fossil' already running.

rfork en
syscfg=/sys/lib/sysconfig
proto=$syscfg/proto/stand-usb
srcroot=/n/boot
quantum=1000000
# size of image in $quantum-byte units.  1900 is enough for production system
# (fs, /n/boot, ~1.2GB); 900 is ample for our install image
# (sources, /n/sources/plan9, ~370MB).
defsize=1900
size=()

fn usage {
	echo usage: $argv0 '[-b boot] [-p proto] [-r root] [-s 10⁶-bytes]' >[1=2]
	exit usage
}

fn sigint sighup sigterm {
	rm -f /tmp/9load
	exit note
}

# process arguments
done=0
argv0=$0
boot=/386/9loadusb
while (~ $done 0 && ! ~ $#* 0 && ~ $1 -*) {
	switch ($1) {
	case -b;	boot=$2; shift
	case -p;	proto=$2; shift
	case -r;	srcroot=$2; shift
	case -s;	size=$2; shift
	case --;	done=1			# no break in rc, alas
	case -*;	usage
	}
	shift
}
if (! ~ $#* 0)
	usage

# special case sources
if (~ $srcroot /n/*)
	srcfs=`{ echo $srcroot | sed 's;^/n/([^/]+).*;\1;' }
if (~ $srcfs sources)
	defsize=900
if (~ $#size 0)
	size=$defsize

# make empty disk image file of maximum size
echo -n 'image: ' >[1=2]
dd -ibs $quantum -obs $quantum -oseek `{hoc -e $size'-1'} -count 1 -quiet 1 \
	</dev/zero >image

# partition it
disk/partfs image
cd /dev/sdXX

# prep it: lay down mbr, fdisk partitions, 9 partitions
echo -n mbr+fdisk+prep... >[1=2]
disk/mbr -m /386/mbr data
disk/fdisk -baw data
disk/prep -bw -a^(9fat nvram fscfg fossil) plan9 >/dev/null

# populate 9fat, nvram, fsconfig
echo -n 9fat... >[1=2]
switch ($objtype) {
case 386
	# we don't normally keep gzipped kernels around,
	# but usb can be flakey and slow, so we'll make one.
	k=/tmp/9pccpuf.gz
	gzip -9 </$objtype/9pccpuf >$k
case amd64
	k=/$objtype/9k8cpu
case *
	echo $0: 'can''t cope with architecture' $objtype >[1=2]
	exit unknown-arch
}
cp $boot /tmp/9load		# force format to record the name `9load'
disk/format -b /386/pbslba -d -r 2 9fat /tmp/9load $k \
	$syscfg/usb/plan9.ini >[2=1] |
	grep -v '^(add .* at clust |Init|type |Adding file|used )'
if (~ $objtype 386)
	rm -f $k
rm -f /tmp/9load
cp /dev/zero nvram >[2]/dev/null
cp /dev/zero fscfg >[2]/dev/null

# fill the fossil
9fs $srcfs
echo -n load fossil... >[1=2]
exec loadfossil /dev/sdXX/fossil $srcroot $proto $syscfg/usb/fossil.conf