pxe success + iscsi `size` feature for devices

[Pierre-Philipp Braun <pbraun%nethence.com@localhost>]

Good day.  I am glad I have the chance to play with NetBSD again.  Yesterday I put pxeboot_ia32.bin inside pxelinux.cfg/default, so I could PXE while I PXE:-)  Seriously, it went fine, and the the vendor-class-identifier trick helped the dhcp server differentiate normal BOOTP requests from those initiated by pxeboot -- this is only optional, one can also provide 'netbsd.gz' at the root of the tftp share to avoid interacting with the boot prompt.  I was just in the mood to talk.

Today's topic is rather iSCSI.  I am pleased to read in the NetBSD 7.1 TARGETS(5) manual that,

     It is possible to use the word ``size'' to use the full size of the pre-
     existing regular file given in the extent name.

However I then realized that it goes for _file_ extends only, not bsd partitions.  In fact, when setting up an extend as a partition,

	# extent        file or device          start           length
	extent0         /dev/rwd0e               0               size

	# target        flags   storage         netmask
	target0         rw      extent0         0.0.0.0/0

I get this error when trying to start iscsi target daemon (identified size is **zero**),

	Starting iscsi_target.
	Reading configuration from `/etc/iscsi/targets'
	target0:rw:0.0.0.0/0
	        extent0:/dev/rwd0e:0:0
	DISK: 1 logical unit (0 blocks, 512 bytes/block), type iscsi fs
	DISK: LUN 0: pid 423:/usr/src/external/bsd/iscsi/lib/../dist/src/lib/disk.c:720: ***ERROR*** error reading "target0"
	pid 423:/usr/src/external/bsd/iscsi/lib/../dist/src/lib/disk.c:886: ***ERROR*** error allocating space for "target0"
	pid 423:/usr/src/external/bsd/iscsi/lib/../dist/src/lib/target.c:1990: ***ERROR*** device_init() failed
	iscsi_target_start() failed

So I guess all I could wish for is the 'size' feature to be able to handle devices sizes automatically.

Best regards and thank you for the good code
-- 
Pierre-Philipp