[gPXE-devel] [PATCH][lkrn] add cmdline and ramdisk support

[Shao Miller]

Wu Fengguang wrote:
>
> Hmm, autoboot defaults to the TFTP download protocol given the
> filename option. This drops a big strength of gPXE.. And you'll need
> another option for kernel parameters (and need to handle spaces in
> between).
>

' filename=http://webserver/foo ' would do the trick.  If such 
command-line processing simply sets the corresponding DHCP options, gPXE 
already looks at the protocol in this DHCP option and uses it.

> You mean the x_cmd:// URI?  That's pretty clean for implementation,
> however sounds ugly as a user interface.
>

Absolutely agreed.  Just a possibility.  It could even be compiled as an 
optional feature and should not require any changes to current gPXE 
files, as far as I can tell.

>
> How about this cmdline syntax:
>
>         APPEND  #!gpxe; dhcp net0; kernel URL root=...; boot;
>
> - the '#!gpxe' declares the start of a gPXE script (this will exclude
>   the BOOT_IMAGE=... added by GRUB)
>
> - the followed ';' declares that the semicolon will be treated as
>   the DELIMITER (think about the '/' in :s/a/b/ for vim)
>
> - each gPXE must end with the DELIMITER, ie. the last ';' is not
>   optional (this will exclude the BOOT_IMAGE=... appended by PXELinux)
>
> > I'd really enjoy reading what the gPXE core developer usual suspects
> > have to offer. :)
>

The February 12th, 2009 incarnation[1] (not the original January 
incarnation) used ';' as command delimiter, so I don't disagree with 
you, there.  Since the boot-loader-appended ' BOOT_IMAGE= ' should fall 
after the last command (which should do some booting), it would 
favourably be ignored...  Unless the booting command should fail, of course.

To be honest, concerns around decisions regarding command syntax have 
been blocks against my submissions for initrd+cmdline and gPXE 
CLI/scripting enhancements, historically, as Stefan has just confirmed.

Stefan Hajnoczi wrote:
>
> How bad is it if only initrd is supported, no lkrn commandline?
>
> Then we don't need to worry about new syntax and code for parsing 
> command lines.
>

Wu Fengguang wrote:
>
> At least I can do with initrd.
>
> I would appreciate if the initrd feature can merged ASAP.
>
> Please don't let the unresolved command line UI stand in the way :)
>

It seems reasonable to be able to split them apart.

[1] 
http://sourceforge.net/mailarchive/message.php?msg_name=F0E5F8699DE1364584CDB894E99713551187F589%40YRDSB5.YRDSB.YRDSB.NET
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