[ipxe-devel] [gPXE] Debugging over UDP

[Michael Brown]

On Wednesday 08 Dec 2010 18:58:11 Vinay Venkataraghavan wrote:
> I just recently started to play with gPXE and would like to step through
>  the process using the debugging options. But I have not been sucessful.
>  Any help would be appreciated.
> 
> The steps I followed are as show below:
> 
> 1. Built an iso image and burned it to a dvd.
> 2. Booted the client machine and broke into the gPXE prompt.
> 3. Executed: ifopen net0
>                    set net0/ip 10.44.4.3
>                       bdgstub udp net0
> 
> 4. On the debugger machine.
> 
>                 gdb
>                 set debug remote 1
>                 file bin/gpxe.lkrn.tmp
>                 target remote udp:10.44.4.3:43770
> 
> Questions:
> 
> 1) What is the name of the corresponding .tmp file to use when I am using
>  an gpxe.iso image. This is not specified in the gPXE documentation.

You want the ".lkrn.tmp" file.  (An .iso image is built using the .lkrn 
binary.)

> 2) I get the following output:
>
> <snip>

Are you able to ping 10.44.4.3 from the machine running gdb?

Also, since you say that you just recently started to play: are you aware that 
there is a substantial amount of built-in debug code that can be enabled 
without having to go to the effort of using gdb?  For example, if you are 
having problems with DHCP, then

  make bin/ipxe.iso DEBUG=dhcp

will show you debugging messages related to DHCP.  You can find some 
description of debug builds at

  http://ipxe.org/download#debug_builds

HTH,

Michael