This is not about boot strapping. This is rather on how to fully boot and run NetBSD over ext2fs. So what ever method you used to load the kernel is fine. We are taking the XEN/PV route here, for convenience.
This is PoC, just for fun. And there are mainly three ways to do this:
d as root-device – that is MUCH EASIER but not possible on bare-metalThis guide is about the second way. In short:
a partition offset and let it fixup the incompatible SunOS BSD labelmkdir /root/guests/netbsdextfs/ cd /root/guests/netbsdextfs/ rm -f netbsdextfs.sparse netbsdextfs.data.sparse dd if=/dev/zero of=netbsdextfs.sparse bs=1000k count=0 seek=4000 dd if=/dev/zero of=netbsdextfs.data.sparse bs=1000k count=0 seek=4000 cat > netbsdextfs <<EOF #kernel = "/data/kernels/netbsd/netbsd-INSTALL_XEN3_DOMU.gz" kernel = "/data/kernels/netbsd/netbsd-XEN3_DOMU.gz" root = "xbd0a" extra = "-v -s" memory = 512 name = "netbsdextfs" vcpus = 4 disk = ['tap:tapdisk:aio:/data/guests/netbsdextfs/netbsdextfs.sparse,xvda,w', 'tap:tapdisk:aio:/data/guests/netbsdextfs/netbsdextfs.data.sparse,xvdb,w'] vif = [ 'bridge=xenbr0,vifname=netbsdextfs.0' ] EOF
start clean
losetup --list | grep netbsd
prepare the DOS partitions
fdisk -v #fdisk from util-linux 2.31.1 fdisk netbsdextfs.sparse n p 1 2048 ALL t a9 a/BOOTABLE p w
now create some (Solaris?) BSD labels from gnu/linux. We will not use it as-is on NetBSD. We just use it temporarily, first to find and locate a place for the ext2fs, then for netbsd to actually find its root-device at sector 4096.
fdisk netbsdextfs.sparse b Do you want to create a BSD disklabel? [Y]es/[N]o: y d d n a 4096 ALL t a a/unknown otherwise unable to mount 0/unused p w q #losetup --all losetup --list losetup --detach /dev/loop1 losetup --find --partscan --show netbsdextfs.sparse ls -lkF /dev/loop1* mkfs.ext2 -O^dir_index,^ext_attr /dev/loop1p5 tune2fs -l /dev/loop1p5 | grep features
should match what we support
resize_inode filetype sparse_super large_file
and proceed
mount /dev/loop1p5 /mnt
ls -alkF /mnt/
#warning you may get all kernels extracted over there, last one being DOMU
for set in /data/kernels/netbsd/sets/*.tar.xz; do
echo -n $set...
tar xJph --numeric-owner -f $set -C /mnt && echo done
done; unset set
cp -v /data/kernels/netbsd/*.gz /mnt/
ls -alkF /mnt/ /mnt/dev/
cd /mnt/dev/
cp -pi MAKEDEV MAKEDEV.linux
vi MAKEDEV.linux
…get rid of -F -R -r -g -u
./MAKEDEV.linux all ls -alkF cd /root/guests/netbsdextfs/ ls -lkF /mnt/etc/passwd* mv /mnt/etc/passwd /mnt/etc/passwd.dist sed '1s@/bin/sh@/bin/ksh@' /mnt/etc/passwd.dist > /mnt/etc/passwd diff -u /mnt/etc/passwd.dist /mnt/etc/passwd cat > /mnt/etc/fstab <<EOF # no dump /dev/xbd0a / ext2fs rw 0 1 #force EOF cat /mnt/etc/fstab mv -i /mnt/etc/rc.conf /mnt/etc/rc.conf.dist cat > /mnt/etc/rc.conf <<EOF . /etc/defaults/rc.conf rc_configured=yes rc_silent=no # /var/run/rc.log no_swap=yes savecore=no wscons=no EOF cat /mnt/etc/rc.conf
If you want to skip the learning curve of this guide, now is a good moment to have a look at the EMBED THE TWEAK section.
umount /mnt fsck.ext2 /dev/loop1p5 fsck.ext2 -f /dev/loop1p5 losetup --detach /dev/loop1 ls -lkF /dev/loop1* #dos and bsd partitions are gone
reaching the single user mode as requested with extra =
cd /data/guests/netbsdextfs/ xl create netbsdextfs -c /bin/ksh alias ll='ls -alkF'
Let us test the features that NetBSD 8.99.36 implements
newfs_ext2fs -I -O1 /dev/rxbd1d
then from the gnu/linux host
file netbsdextfs.data.sparse tune2fs -l netbsdextfs.data.sparse dumpe2fs netbsdextfs.data.sparse > netbsdextfs.data.sparse.dumpe2fs.dist dumpe2fs netbsdextfs.data.sparse | grep ^Group | wc -l #31 dumpe2fs netbsdextfs.data.sparse | grep 'Backup superblock' | wc -l #7
gives
Linux rev 1.0 ext2 filesystem data, UUID=29a111d1-03f8-9048-9b95-30446b526f74 (large files) tune2fs 1.44.1 (24-Mar-2018) Filesystem volume name: <none> Last mounted on: <not available> Filesystem UUID: 29a111d1-03f8-9048-9b95-30446b526f74 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: resize_inode filetype sparse_super large_file Default mount options: (none) Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 500960 Block count: 1000000 Reserved block count: 50000 Free blocks: 982309 Free inodes: 500949 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 244 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 16160 Inode blocks per group: 505 Last mount time: n/a Last write time: Sat Mar 30 16:12:01 2019 Mount count: 0 Maximum mount count: 20 Last checked: Sat Mar 30 16:12:01 2019 Check interval: 15552000 (6 months) Next check after: Thu Sep 26 16:12:01 2019 Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 128
check that NO tmpfs /dev is there
mount mount -vv ls -alkF /dev/xbd0* ls -alkF /dev/rxbd0*
notice difference on what the kernel vs disk says
disklabel xbd0 disklabel -r xbd0
we not only need this for -e/-R to work on /tmp
#mount -t tmpfs none /tmp mount -u -o rw /dev/xbd0a /
but also for fixing device files ownerships
cd /dev/ ./MAKEDEV all cd /
craft your own (total sectors / 2048 = cylinders)
cat > xbd0c.label <<EOF99 # /dev/rxbd0: type: ESDI disk: xbd0 label: crafted flags: bytes/sector: 512 sectors/track: 2048 tracks/cylinder: 1 sectors/cylinder: 2048 cylinders: 3906 total sectors: 8000000 rpm: 3600 interleave: 1 trackskew: 0 cylinderskew: 0 headswitch: 0 # microseconds track-to-track seek: 0 # microseconds drivedata: 0 4 partitions: # size offset fstype [fsize bsize cpg/sgs] a: 7995904 4096 Linux Ext2 4096 0 c: 7997952 2048 unused 0 0 d: 8000000 0 unused 0 0 EOF99 disklabel -R xbd0 xbd0c.label disklabel -R -r xbd0 xbd0c.label disklabel xbd0 disklabel -r xbd0
then exit single user mode and the system boots
^D
cp -pi /mnt/etc/rc /mnt/etc/rc.dist vi /mnt/etc/rc ... umask 022 #CWD is / echo -n RE-GENERATING DEVICE FILES WITH PROPER OWNERSHIPS... cd /dev/ ./MAKEDEV all && echo DONE cd / echo CURRENT MOUNT SITUATION IS mount echo -n MOUNTING /tmp AS TMPFS... mount -t tmpfs none /tmp && echo DONE echo MOUNT SITUATION IS NOW mount echo -n WRITING /tmp/xbd0c.label... cat > /tmp/xbd0c.label <<EOF99 && echo DONE # /dev/rxbd0: type: ESDI disk: xbd0 label: crafted flags: bytes/sector: 512 sectors/track: 2048 tracks/cylinder: 1 sectors/cylinder: 2048 cylinders: 3906 total sectors: 8000000 rpm: 3600 interleave: 1 trackskew: 0 cylinderskew: 0 headswitch: 0 # microseconds track-to-track seek: 0 # microseconds drivedata: 0 4 partitions: # size offset fstype [fsize bsize cpg/sgs] a: 7995904 4096 Linux Ext2 4096 0 c: 7997952 2048 unused 0 0 d: 8000000 0 unused 0 0 EOF99 echo -n APPLYING DISKLABEL FIXUP... disklabel -R xbd0 /tmp/xbd0c.label && echo DONE echo -n YET AGAIN ON THE DISK... disklabel -R -r xbd0 /tmp/xbd0c.label && echo DONE echo -n GETTING RID OF TMPFS... umount -aft tmpfs && echo DONE echo MOUNT SITUATION IS BACK TO mount
DO NOT FORGET TO GET RID OF THOSE TWEAKS ONCE THE SYSTEM HAS BOOTED PROPERLY. YOU DO NOT WANT TO RE-WRITE THE LABELS AND RE-GENERATE DEVICE FILES AT EVERY SYSTEM STARTUP.
disk label it is on sector 1 (not 0 which is reserved for mbr, even on a DOS partition) of the a9/netbsd DOS partition
dd if=/dev/xbd0d bs=512 skip=2049 count=1 | hexdump -vC
modstat | grep ext2fs # fsck_ext2fs /dev/xbd0a ** /dev/rxbd0a BAD SUPER BLOCK: VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE LOOK FOR ALTERNATE SUPERBLOCKS? [yn] y CANNOT READ: BLK 8388608 CONTINUE? [yn] ^C
reproduce with
#mkfs.ext2 -r0 netbsdextfs.data.sparse mkfs.ext2 -O^dir_index,^ext_attr netbsdextfs.data.sparse disklabel -e xbd1 d: 8000000 0 Linux Ext2 4096 0 # (Cyl. 0 - 3906*)
fixed by mlelstv – sbin/fsck_ext2fs/setup.c 1.36
DOS partitions
Disk /dev/loop1: 3.8 GiB, 4096000000 bytes, 8000000 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x7e91a4e9 Device Boot Start End Sectors Size Id Type /dev/loop1p1 * 2048 7999999 7997952 3.8G a9 NetBSD
BSD labels
Disk /dev/loop1p1: 3.8 GiB, 4096000000 bytes, 8000000 sectors Geometry: 1 heads, 2048 sectors/track, 3906 cylinders Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: bsd Slice Start End Sectors Size Type Fsize Bsize Cpg a 4096 7999999 7995904 3.8G unknown 0 0 0 c 2048 7999999 7997952 3.8G unused 0 0 0 d 0 7999999 8000000 3.8G unused 0 0 0 Partition table entries are not in disk order.
check if -u can be used with MAKEDEV to just update ownerships