mount vdi

[Joe Sciulli]

Is it possible to mount virtualbox vdi file on the FreeBSD host?  This appears to be doable on windows and linux hosts, which basically is done in two steps: 1. find offset in the image. 2. mount the image with that offset.

I'm trying to do the same thing on FreeBSD, and found the undocumented and deprecated command still works:

VBoxManage internalcommands dumphdinfo freebsd_home.vdi

I got the following for the virtual disk image holding the /home (no root hence no MBR) disk for a FreeBSD guest:

Header: offBlocks=4096 offData=28672

But since the mount command in FreeBSD doesn't support "offset", I have to dd the image into another file.  I believe the default "block" size in dd is 512 bytes, so the offset 28672 (bytes?) is 56 blocks.  So I used the command:

dd skip=56 if=freebsd_home.vdi of=freebsd_home_56.vdi

Then attempt to mount it:

mdconfig -a -t vnode -f /tmp/freebsd_home_56.vdi -u 0
mount /dev/md0 /tmp/aaa/
mount -t cd9660 /dev/md0 /tmp/aaa/

unfortunately both the above two mount commands failed with "Invalid argument".  I tried skip=28672 to no avail as well.  Anything did I do wrong?

Or is there any other solution in FreeBSD host to mount virtualbox vdi file?  There appears to be a "vdfuse" but is not ported yet, and the attempt to port appears to be not for VirtualBox 4.