Formal support for PXELINUX boot / install

A small part of Step 1 is now complete, in as much as the buildimage.pl script recognizes "pxelinux" as a build image type.

• cc taspts added

We could provide a leaf version as an application for use in Qemu or virtualbox that can act as an PXE server with script for installing on target.

The same application could also install itself locally.

This would bypass the problem with using disk.img that lacks ioctl and different media having different metrics.

There exist some old stuff a pxe.lrp
http://leaf.sourceforge.net/doc/bupxebooting.html

While it is essential to use TFTP for the very first step - downloading pxelinux.0 (or gpxelinux.0) and its configuration file - it is not essential to use TFTP for all of the subsequent downloads.
By using gpxelinux.0 either HTTP or FTP can be used to download the kernel and initrd.
Then, for downloading leaf.cfg and the Package .lrp files, any sensible file transfer mechanism can be used:

• FTP
• HTTP(S)
• SSH (or rather scp / sftp)
• NFS
• CIFS ?

Basically all that we need is to establish network connectivity when running "init" and to provide the relevant file transfer client software for the chosen protocol.

We should try to support as many of these file transfer protocol options as is practical, with some simple means of specifying which one should be used. Other distributions (e.g. http://www.minimyth.org/) do this by using a "URL" format for the path. For example we might choose to support:

• tftp://server/directory/
• http://server/directory/
• ssh://user@server:directory/
• dev:///dev/sda1:vfat (the current LEAFCFG and PKGPATH standard with "dev://" prepended)

• milestone changed from Bering-uClibc 4.0.1 to Bering-uClibc 4.1

Provisionally allocated to Milestone 4.1

Seems that "curl" might be a good option for the file download (and upload) rather than using multiple different file transfer protocol clients. It supports lots of good protocols:

• TFTP
• HTTP(S)
• FTP(S)
• SSH (actually SCP and SFTP) when linked against "libssh2"
• FILE (i.e. <file: dir1="" dir2="" file=""> for a local file) </file:>

and several more email-related protocols (e.g. SMTP, IMAP, POP3)

I have a "curl" package in development (for "asterisk" as it happens). Sounds like it might be a useful utility to have available anyway.

• owner set to davidmbrooke
• status changed from new to assigned

I am making some progress on this and now have PXE boot working on a development system.
The basic requirements are:

• Add files to a special PXE initrd.lrp: network card driver .ko's, DHCP client. "ip" command, file transfer client etc.
• Change /init (root.linuxrc) to bring up the network if requested (it looks for a kernel command-line parameter) and to accept an alternative style of LEAFCFG and PKGPATH (e.g. http://1.2.3.4/path/leaf.cfg) in addition to the existing /dev/sda1:vfat format.
  • I want to retain a single /init script, so that we don't have to maintain two copies. The downside is that we need to change the existing /init script, which carries some risk of breaking current operations.
  • Not sure whether this is too risky to try to include in 4.0-beta3 and hence 4.0. I will review the changes and make a judgement.
• Some minor changes to buildimage.pl and the creation of buildimage.cfg files for PXELINUX images.

Automatically saving back changes over the network is more complicated so I propose to leave that for later.

There are some more design decisions to make:

• Which file transfer client to use. "curl" is working OK for me in development, and it is very flexible, but it is quite large. Maybe OK to ship that by default - users can always edit initrd.lrp and replace curl with something else.
• What set of network card drivers to include by default.

• milestone changed from Bering-uClibc 4.1 to Bering-uClibc 4.2