Bug#509723: Support TFTP preseed fetch method

["Trent W. Buck" <trentbuck@gmail.com>]

Package: debian-installer
Severity: wishlist

(I have a feeling I already reported this and been tagged WONTFIX;
apologies if this is the case and I can't find it in the BTS.)

Currently AFAICT the preseed file must be supplied either within the
initrd, on local media (including the install CD), or via HTTP or FTP.

I would find it useful if the preseed file could be fetched via TFTP.

This is particularly useful when netbooting, as I already have the
netboot files in debian-installer/ -- it would be easy for me to have
a second tree d-i/{etch,lenny}/preseed.cfg.

This is also useful when doing "fake" netboots with qemu, because then
I could do something like

    qemu -tftp d-i/etch/ -bootp preseed.cfg \
    -kernel debian-installer/linux -initrd debian-installer/initrd.gz

without needing to run a separate http process.  (QEMU has built-in
support for providing DHCP and TFTP to the VM, but not HTTP.)

-- System Information:
Debian Release: 5.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 2.6.26-1-686 (SMP w/1 CPU core)
Locale: LANG=en_AU.utf8, LC_CTYPE=en_AU.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash